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height="12.23267716535433in"}

Priority Science Questions

-   **How are ocean ecosystems and the biodiversity they support
    influenced by climate and environmental variability and change, and
    how will these changes occur over time?**

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-   **How do carbon and other elements transition between ocean pools
    and pass through the Earth System, and how do biogeochemical fluxes
    impact the ocean and Earth\'s climate over time?**

-   **How (and why) is the diversity and geographical distribution of
    coastal marine habitats changing, and what are the implications for
    the well-being of human society?**

-   **How do hazards and pollutants impact the hydrography and biology
    of the coastal zone? How do they affect us, and can we mitigate
    their effects?**

Dear Reader,

The advent of satellite oceanography in the late 1970\'s has given rise
to a profound realization that our planet\'s ocean, covering 71% of the
Earth\'s surface, plays a critical role in modifying weather and
climate, and in sustaining life on Earth. Recent views of nearby planets
lacking an ocean expose a stark contrast to our Earth\'s habitability.
Satellite sensors have revolutionized our perceptions of the ocean
environment and our understanding of the linkages among the ocean and
other components of the Earth system, and they have revealed a diversity
and complexity in ocean ecosystems that had not been appreciated through
traditional oceanographic approaches. Further, the explosive growth of
human populations along coastal margins now places increasing pressure
on these dynamic ecosystems, modifying natural processes and, in many
cases, putting life, health, and property at risk from hazards inherent
to the ocean.

Despite this profound realization, the oceans remain largely unexplored,
with many discoveries waiting to be made. The past three decades have
given us only a brief glimpse of a constantly changing Earth system, in
which natural and human factors interplay. We have learned that
scientific observations from the vantage point of space help solve
important problems. Advanced technologies and frequent, repeated
satellite observations, as well as robust field and laboratory
measurements of the ocean are essential to our ability to observe and
predict changes.

NASA is leading national and international efforts to define future
space technologies and missions. Satellite-based observations help
connect ground-based observations, and serve to integrate regional and
global Earth observing systems that are being designed and implemented.
In turn, these ground observatories are critical to ensure the highest
quality data can be derived from satellite sensors. In this spirit,
NASA\'s Ocean Biology and Biogeochemistry (OBB) program scientist
engaged the research community in an effort to develop advanced
scenarios and strategies to address the important science questions yet
to be answered by the program within the context of the vision of NASA's
Science Mission Directorate. A working group of experts summarized the
state of the science and collected research community comments both
electronically and during presentations at a series of national and
international meetings.

This report is the product of these efforts. It outlines a strategy for
NASA to lead in the scientific application of remote sensing
technologies for the exploration and understanding of biological and
biogeochemical processes of our oceans. The report addresses the
interplay between chemistry and biology at the scale of the planet, the
diversity and resilience of our coastal habitats, hazards that pose
risks to the environment and to human communities, and how these
processes feed back to global climate. This is a living document that
will evolve as improvements in our understanding of ocean processes
unfold and lead to an optimal strategy for supporting further science
advances. The vision is to fully discover the mechanisms and
interactions that sustain life on our ocean planet, as only NASA can.

Sincerely,

Paula Bontempi

Chair, Ocean Biology and Biogeochemistry Working Group (OBBWG)

**Executive Summary**

The Earth system is a delicate balance among the exchanges of energy,
water, and materials from land, ocean, atmosphere, and ice. The oceans
play a critical role in Earth's climate, containing the most unexplored
environment. Understanding the ecosystems, biogeochemistry, habitats,
and hazards of our oceans in a varying and changing climate is critical
for sustained life on Earth. NASA's oceanographic research from space
has revealed decadal-scale changes in the ocean biosphere. These
discoveries raise new science questions that help define the course of
the NASA Ocean Biology and Biogeochemistry (OBB) research program for
the coming decades. The objectives of the next phase of research are to
explore and seek understanding of the structure and variability of ocean
ecosystems, biogeochemical cycling of carbon and other important
elements, fragile habitats of our coastal zones, and the role of natural
and anthropogenic hazards. This new phase includes research on the
relationship between these topics and ecosystem health and services,
human health, welfare, recreation, and commerce. Discoveries over the
next quarter century of NASA's research into the biological and
biogeochemical functioning of the ocean will enable the formulation of
effective strategies for assessing, adapting to, and managing climate
change. NASA brings the unique vantage point of space-based observations
and improved Earth System modeling capabilities to a national and
international network of ground-based observations. From this scientific
foundation, NASA, along with its national and international partners,
must carefully formulate plans for space-based missions in support of
these research objectives. The technologies and observational strategies
proposed here promise to advance our understanding of our home planet in
the coming decades. This understanding will help us protect the
environment that surrounds us and our own health, and ultimately help
ensure our survival on the only planet where we know life exists.

Over the past year and a half, a working group representing the ocean
biology and biogeochemistry research community carefully developed the
next set of science questions to guide NASA's Ocean Biology and
Biogeochemistry research program, and posed advanced observational
scenarios and strategies to address these questions. The result includes
a prioritized list of satellite missions required to implement these
strategies over the next 25 years of NASA observations of the ocean
biosphere. Comments from the broader research community were solicited
widely, and responses were incorporated into this draft plan.

Four basic science questions were posed, covering different aspects of
the NASA Ocean Biology and Biogeochemistry program. These four
overarching questions address 1) marine ecosystems, 2) ocean
biogeochemistry, 3) coastal habitats, and 4) hazards. Each topic
addresses feedbacks related to humankind. These questions define the
suite of geophysical observations needed to conduct the research, and
the critical set and sequence of future sensors and missions required to
implement a robust, yet viable integrated ocean observing strategy. The
answer to these questions, with consideration of science and societal
urgency, technology readiness, and supporting value for subsequent
measurement components, leads to four recommended integrated mission
themes:

-   Separation of in-water constituents (e.g., organic and inorganic
    substances) in global waters, which advanced corrections for
    atmospheric effects on satellite ocean measurements

-   High temporal and spatial resolution measurements of coastal
    phenomena and habitats

-   Active assessments of plant physiology and the function of different
    groups of plants in aquatic ecosystems

-   Environmental variability of the surface ocean, including the depth
    of the mixed layer

Specific strategies are recommended for each component over a 25 year
time-frame, with immediate (1 -- 5 years), near-term (5 -- 10 years),
and long-term (10 -- 25 years) goals. Some of the mission themes require
new technical milestones, while others are nearly ready to go. The
following are proposed as the top NASA Ocean Biology and Biogeochemistry
mission priorities:

1.  global hyperspectral imaging radiometer in sun synchronous orbit,
    focused on the accurate separation of in-water constituents and
    correction of the contribution of aerosols,

2.  global hyperspectral imaging radiometers in geostationary orbit,
    which will enable global and regional observations of dynamic and
    complex coastal and shelf processes and discrimination of in-water
    constituents on sub-daily time scales and at high spatial resolution
    (200 m or better) at nadir,

3.  multi-spectral, high spatial resolution imager to observe coastal
    habitats and ecosystems at unprecedented scales and accuracies,

4.  deployment of active approaches for probing plant physiology and
    functional composition from polar satellite orbit using laser
    technologies

5.  implementation of portable sensors on suborbital platforms

6.  development of new technologies for the assessment of ocean mixed
    layer depth from satellite orbit, and

7.  development of new technologies to obtain ocean particle profiles
    and aerosol column distributions.

This recommended set of missions requires that NASA continue the
systematic, decadal scale sampling of ocean processes, the *in situ*
validation of the satellite data products, full radiometric
characterization of satellite sensors, and continual development of
technologies for new satellite measurements, in situ sensors for
vicarious calibration and data product validation, algorithm
development, data processing, archive, and distribution. The long-term
expectation is that a satellite and suborbital based observation network
to assess biological stocks and rates is integrated with ground-based
observatories and observing systems being developed by national and
international entities, thus enabling the detailed assessment of
processes that affect life on Earth on a wide variety of time and space
scales.

The next step to enable visionary Earth System Science requires that
NASA address the interplay between chemistry, biology, physics, and
geology at the scale of the planet, in tight partnership with the
national and international science, resource management, and other
operational communities. It requires that we examine the diversity and
resilience of our coastal habitats, that we study hazards that threaten
the environment and our communities, and understand the feedbacks that
affect global climate. This can only happen by a shared vision of
support and focused collaboration on the research topics presented here.
The goal is to fully discover the mechanisms and interactions that
sustain life on our ocean planet for future generations, while inspiring
the next generation of explorers as only NASA can.

**Table of Contents**

[Earth's Undiscovered World 7](#earths-undiscovered-world)

[Top Issues 8](#top-issues)

[Top-Order 'State of the Science' 10](#top-order-state-of-the-science)

[Scientific Imperatives 12](#scientific-imperatives)

[How are Ocean Ecosystems and the Biodiversity they Support Influenced
by Climate or Environmental Variability and Change, and How Will These
Changes Occur over Time?
14](#how-are-ocean-ecosystems-and-the-biodiversity-they-support-influenced-by-climate-or-environmental-variability-and-change-and-how-will-these-changes-occur-over-time)

[How do Carbon and Other Elements Transition between Ocean Pools and
Pass through the Earth System, and How do These Biogeochemical Fluxes
Impact the Ocean and Earth\'s Climate over Time?
18](#how-do-carbon-and-other-elements-transition-between-ocean-pools-and-pass-through-the-earth-system-and-how-do-these-biogeochemical-fluxes-impact-the-ocean-and-earths-climate-over-time)

[How (and Why) is the Diversity and Geographical Distribution of Coastal
Marine Habitats Changing, and What are the Implications for the
Well-Being of Human Society? 23](#refheading___toc136168901)

[How do Hazards and Pollutants Impact the Hydrography and Biology of the
Coastal Zone? How do they affect us, and can we Mitigate their Effects?
28](#how-do-hazards-and-pollutants-impact-the-hydrography-and-biology-of-the-coastal-zone-how-do-they-affect-us-and-can-we-mitigate-their-effects)

[Recommendations for an Integrated Living Ocean Program
32](#recommendations-for-an-integrated-living-ocean-program)

[Observational Strategies 36](#observational-strategies)

[Supporting In Situ & Space-Based Measurements
56](#supporting-in-situ-space-based-measurements)

[Systematic Observations 58](#systematic-observations)

[Research, Analysis and Modeling 59](#research-analysis-and-modeling)

[Education 60](#educationpublic-outreach)

[Essential Partnerships 61](#essential-partnerships)

[Summary 64](#summary)

[Figure Credits 70](#figure-credits)

Table of Acronyms

[Biological Oceanography and Biogeochemistry Working Group
72](#ocean-biology-and-biogeochemistry-working-group)

#  

# Earth's Undiscovered World

> Earth is the living blue planet. Its functioning is only partially
> understood, but it remains the only planet we know that supports life.
> The vast oceans are critical to the habitability of Earth, covering
> 71% of its surface and creating 96% of its living environment. The
> oceans (and thus Earth) are profoundly affected by human and natural
> environmental changes. Daily human activities, especially along our
> coasts, interact in complex ways with the natural environment to
> change our surroundings. Many of these changes are accelerating, and
> their implications for the health of the planet, humans, and all other
> organisms extend far into the future. The enormous size and remoteness
> of the oceans has long hindered a thorough understanding of how and
> why our planet changes. This obstacle is being overcome through NASA's
> pioneering programs that utilize the unique vantage point of space to
> routinely explore and study the Earth system. With these tools we can
> now discover the many secrets of our planet as never before.
> Understanding Earth's oceans will ultimately allow us to better
> describe and predict Earth system mechanisms that are affected by
> natural and anthropogenic climate changes, and how these processes
> feed back on the overall Earth system over time. While the journey
> through space inspires exploration, the world beneath the ocean's
> shimmering surface is even less familiar than the heavens above, and
> awaits our inquisition and imagination to yield unanticipated new
> insights on the functioning of our home planet.
>
> The Earth system is a delicate balance among ocean, land, ice, and
> atmosphere. NASA's oceanographic research from space over the past
> three decades has revealed synoptic, decadal-scale changes in the
> ocean biosphere. These discoveries raise new questions that now define
> the course of research for the coming three decades. From this
> scientific foundation, NASA must carefully formulate plans for
> requisite space-based missions. The resultant next phase of research
> will extend our understanding of how ocean ecosystems, elemental
> cycles, coastal habitats, and hazards influence Earth's ecosystem
> health and services, human health, welfare, recreation, and commerce.
> NASA's Ocean Biology and Biogeochemistry Research Program will also
> enable the formulation of effective strategies for assessing, adapting
> to, and managing climate change through space-based observations and
> improved Earth System modeling capabilities. ***This document is a
> blueprint for NASA's space-based research of the Earth's living ocean
> for the next 25 years.***

## Top Issues

### Evolving Ecosystems

> ![](media/image2.png){width="0.8862204724409449in"
> height="0.4125984251968504in"}![](media/image3.png){width="0.9216535433070866in"
> height="0.7125984251968503in"}![](media/image4.jpeg){width="0.6736220472440945in"
> height="0.6771653543307087in"}![](media/image5.jpeg){width="0.5826771653543307in"
> height="0.610236220472441in"}![](media/image6.jpeg){width="0.8153543307086614in"
> height="0.5255905511811023in"}![](media/image7.jpeg){width="0.7783464566929134in"
> height="0.9015748031496063in"}![](media/image8.jpeg){width="0.7318897637795275in"
> height="0.7881889763779527in"}![](media/image9.jpeg){width="0.7090551181102362in"
> height="0.59251968503937in"}![](media/image10.jpeg){width="0.5007874015748032in"
> height="0.41338582677165353in"}![](media/image11.jpeg){width="1.0637795275590551in"
> height="0.6547244094488189in"}The oceans are teeming with life of
> various types and forms. From fish, birds, turtles, and whales to
> bacteria, phytoplankton, and zooplankton, the oceans support a wide
> diversity of living organisms. Size is one measure of diversity, and
> in the oceans organisms range over nearly eight orders of magnitude in
> size, from tiny marine viruses of \~0.1 micron in length, to the
> largest animal to have ever lived on Earth, the blue whale, at nearly
> 30 meters in length. The variety of ecological interactions among
> organisms is another measure of diversity. Ocean life is
> interconnected by complex food webs. These ecosystems are highly
> productive and resilient, and provide a wide assortment of services to
> humankind. We have grown to depend on these services to advance
> commerce and transportation, to derive food, and to recreate and
> sustain our culture. ***In an ever-changing world, how can we best
> understand and protect the trophic structure, productivity, and
> resilience of very large marine ecosystems of our planet?***

Diverse life forms contribute to marine ecosystems.

### Carbon Cycle and Biogeochemistry

> ![](media/image12.png){width="1.9902777777777778in"
> height="2.077777777777778in"}Life as we know it began in the ocean.
> More than four billion years later, ocean plants and animals continue
> to play a vital role in the sustenance of the biosphere and regulation
> of our climate. The transfer of carbon dioxide (CO~2~) into organic
> material in the oceans by tiny, single-celled plants known as
> phytoplankton, the processing of other life-essential elements, and
> respiration, are keyed to environmental conditions and highly
> sensitive to climate variability. Through our actions, these elemental
> cycles are being profoundly altered. ***How can we quantify ocean
> biogeochemical cycles and predict their effects on the Earth System in
> the future?***

### Fragile Habitats

> The world's coastal habitats constitute areas of intense human growth
> and commercial relevance. The resilience of these habitats is finite
> and coastal habitats are currently threatened by environmental change
> and direct human impacts. Recent changes include catastrophic
> degradation of global coral reef environments through ocean
> acidification and other environmental events, chronic beach
> contamination events, hypoxia in estuaries and the coastal ocean, and
> water quality degradation due to industrial, agricultural, and
> residential pollution. Human pressures include energy and agricultural
> influences that extend throughout Earth's watersheds and feed into
> coastal zones. ***In the face of projected human population increases
> and associated consumption of natural resources, how can we best
> manage our precious coastal habitats for future generations?***

### ![](media/image13.jpeg){width="2.908333333333333in" height="1.9388888888888889in"}

### Hazards and Health

> Recent events have illustrated the devastation and loss of human life,
> property, and commerce from environmental hazards that have impacted
> coastal zones. Supporting over one quarter of the globe's population
> and nearly half of the U.S. population, coastal regions are
> increasingly vulnerable to both chronic and acute hazards. Coastal
> zone hazards include sea level rise, coastline erosion, flooding of
> low-lying areas, and plumes of noxious algae, toxins, pollutants,
> pathogens, and suspended matter. ***How can we best forecast, assess,
> and respond to the environmental hazards that shape our coasts and
> sustain the marine and human life dependent upon coastal resources?***

![](media/image14.jpeg){width="1.7098425196850393in"
height="1.8590551181102362in"}![](media/image15.png){width="1.9437007874015748in"
height="1.3929133858267717in"}![](media/image16.jpeg){width="2.2299212598425195in"
height="1.4507874015748032in"}

## Top-Order 'State of the Science'

> **E**arth's ocean is changing, whether one looks to the climate,
> fisheries, or coastal habitats for evidence. Prior to the 1970's,
> ocean researchers' basic understanding of the ocean was largely
> founded on ship-based studies, which yielded a coarse and incomplete
> picture of a dynamic, complex, and evolving ocean. With the launch of
> the Coastal Zone Color Scanner (CZCS) in 1978, NASA began providing a
> space-based view of the Earth's ocean biosphere. Subsequent
> space-based NASA sensors made it possible to visualize global patterns
> in phytoplankton pigment (or chlorophyll) concentrations in space and
> time, and relate these observations to ocean surface temperature,
> wind, and circulation patterns. Finally, scientists had an
> unprecedented tool by which the Earth's ocean biosphere could be
> comprehensively studied and monitored.
>
> After the demise of the CZCS mission in 1985, a decade went by with no
> satellite observations of the ocean biosphere until the launch of the
> Ocean Color and Temperature Scanner (OCTS) in 1996 by the Japanese
> Aerospace Exploration Agency (JAXA, formerly the National Space
> Development Agency of Japan, NASDA). After the short life of the OCTS
> mission, NASA and Orbital Sciences Corporation's SeaWiFS (Sea-viewing
> Wide Field-of-view Sensor) launched in 1997, while two MODIS (Moderate
> Resolution Imaging Spectroradiometer) sensors were launched in 1999
> and 2002. These sensors have supported many significant scientific
> contributions. However, these missions are long beyond their planned
> prime lives, and have only a limited measurement capability.
>
> Two important lessons have been learned from the history of ocean
> biology and biogeochemical measurements from space: a) gaps in
> observational time series such as occurred between the demise of CZCS
> and the launch of OCTS, severely impact our understanding of and
> ability to model ocean systems (ecology, biology, carbon cycling) and
> their role in the Earth System (as well as any impact for humans), and
> b) we now know the specific measurement requirements needed in future
> space-based measurements to overcome current limitations in our
> scientific knowledge of ocean processes.
>
> Passive ocean color sensors, like CZCS, only observe the upper sun-lit
> surface layer of the ocean. However, when coupled with *in situ*
> observations and numerical models, these space-based observations
> provide a three-dimensional understanding of ocean processes, their
> complexity, and their interactions with other parts of the Earth
> system. Ocean remote sensing allows scientists to effectively 'take
> the pulse' of our living Earth. Combining different NASA satellite
> technologies has afforded new scientific insights on how ocean physics
> and biology are coupled. This laid the groundwork for comprehensive
> assessments of global ocean primary productivity, the process by which
> phytoplankton grow and fix carbon and thereby support nearly all ocean
> ecosystems. NASA's technology has enabled the observation of changes
> in ocean plant biomass and productivity seasonally, annually, and even
> from day to day. This has led to the discovery of large-scale
> biological patterns associated with the dispersal of river water, the
> impacts of El Nino-Southern Oscillation events on changes in
> fisheries, and the influence of ocean biology on air-sea exchange of
> carbon dioxide.
>
> Interdisciplinary research involving observations from various
> space-based and ground-based sensors continues to focus on linking
> data from terrestrial, aquatic, and atmospheric environments of the
> Earth to study biogeochemical cycling, ecology, climate variability
> and change, the solid Earth, and the water and energy cycle. NASA's
> modeling, analysis, and prediction program (MAP) is focused on
> integrating interdisciplinary and multi-disciplinary NASA research
> efforts by supporting pioneering work on climate and ecological model
> development, as well as their linkage, to improve the nation's ability
> to manage ecosystems. Continued exploration and research based on new
> measurements of Earth's living ocean are essential to the goal of
> working with our international partners to manage global ocean
> ecosystems while better understanding and enabling adaptation to
> climate change.

# 

# 

# 

# 

# 

# Scientific Imperatives

### Studying Ocean Biology and Biogeochemistry from Space 

> **T**he oceans have a key role in the Earth System, particularly
> pertaining to climatic and environmental change. It cannot be
> overstated that the Earth is the "Ocean Planet" of our solar system.
> We now recognize that changes in the Earth System do not occur in an
> isolated fashion, but are largely coupled through relationships
> between land, ocean, and atmosphere. Satellite remote sensing has been
> instrumental in revealing this insight. The coastal margins, home to
> the majority of the human population, are subject to anthropogenic
> alterations that impact marine habitats and ecosystems, as well as the
> goods and services they provide. It is only through space-based
> observations, combined with complementary *in situ* and numerical
> modeling studies, that we can advance the understanding of ocean
> biology and biogeochemistry from local to global scales. While there
> remains considerable uncertainty about what specific changes will
> occur, continued population growth and human impacts together with
> natural cycles will lead to significant changes in our Earth System. A
> comprehensive space-based Earth observation program is necessary to
> assess and predict these changes and to responsibly manage our fragile
> resources and ecosystems. Biological and biogeochemical regimes in the
> upper ocean can respond to and therein be indicators of changes in
> Earth's climate and local environmental processes. Ocean biology and
> biogeochemistry research is a critical link to physical oceanographic,
> land, and atmospheric observations, and must be intensively studied if
> NASA is to understand the comprehensive Earth System. Integration
> among research programs and science Focus Areas
> (http://science.hq.nasa.gov/earth-sun/science/) within Earth Science
> is essential to future discovery and research.

### NASA's Role

> NASA\'s mission includes improving understanding of the oceans through
> cutting-edge research by implementing technological advances,
> space-borne global observing capabilities, and integrating new
> knowledge of the Earth system into predictive models. NASA's ocean
> research programs encompass the sub-disciplines of Physical
> Oceanography and Ocean Biology and Biogeochemistry. NASA\'s ocean
> research and modeling activities span from global and coastal ocean
> scales, to the Great Lakes, and down to smaller lakes and rivers.
> Aspects of ocean modeling (e.g., global circulation, air/sea gas
> exchange, carbon cycle, ecology) are supported in partnership with the
> Modeling, Analysis, and Prediction Program. The Cryospheric Sciences
> Program supports research and modeling activities for the
> high-latitude ice-covered oceans. Ocean-relevant research is
> integrated with other aspects of the Earth system through NASA's
> Interdisciplinary Science Program. All NASA research data are
> available to researchers worldwide.
>
> Satellites provide the basic observations upon which most of NASA's
> ocean research is based. However, there are synergies with local and
> global *in situ* observatories supported by other U.S. agencies,
> including the National Oceanic and Atmospheric Administration (NOAA),
> the National Science Foundation (NSF), the U. S. Navy, other U.S.
> agencies and international partners. Earth observing missions within
> NASA's Science Mission Directorate fall into two general areas:
> systematic and exploratory. Calibration and validation activities
> based on *in situ* and laboratory observations, as well as focused
> oceanographic field studies ensure the quality, utility, and best use
> of climate and Earth System data records required for scientific
> research at NASA and science-based resource management efforts within
> other U.S. agencies.
>
> NASA's strength in oceanography has traditionally been in providing
> the global "blue water" view of the planet from space. However, there
> is a growing realization that remote sensing can also help us
> understand processes along the coast. These areas present growing
> societal and practical challenges, and they are connected to inland
> processes through rivers and the atmosphere. Understanding coastal
> processes requires the synoptic views possible only from high
> altitudes such as from aircraft and satellites. NASA seeks to
> aggressively address coastal ocean science questions by designing and
> implementing new missions for coastal seas and developing
> high-resolution coastal models that are nested within global-scale
> numerical models.
>
> Understanding the ice-covered polar regions, which are highly
> vulnerable to changes in climate, is a high priority of NASA's
> research activities. NASA has led the way in using satellite sensors
> to derive ice concentration, extent, temperature, and motion to
> understand high-latitude oceanographic processes, particularly in the
> context of climate changes in the Arctic and Antarctic areas. Our
> proposed new missions will further elucidate the relationships between
> ocean biogeochemistry and climate in the sensitive polar regions.
>
> What is the optimal complement of missions our society requires to
> address critical gaps in knowledge? What new tools can NASA develop to
> support science-based ecosystem approaches to management? ***These and
> other questions can be traced to four fundamental underlying science
> questions. These questions are posed in the following sections, as are
> the strategies to address them. The questions are used to guide NASA
> in developing an ocean biology and biogeochemistry observing strategy
> for the next three decades***. The four science questions are
> seamlessly linked with each other and support other national science
> plans, including NASA\'s interdisciplinary Earth Science Research
> Strategy.

##  

## How are Ocean Ecosystems and the Biodiversity they Support Influenced by Climate or Environmental Variability and Change, and How Will These Changes Occur over Time? {#how-are-ocean-ecosystems-and-the-biodiversity-they-support-influenced-by-climate-or-environmental-variability-and-change-and-how-will-these-changes-occur-over-time .Style-Heading-2-+-Light-Blue}

### The Challenge

> Ocean ecosystems are the living communities of plants, animals, and
> other biological components like bacteria embedded in the physical
> environment of the ocean. They function collectively as a unit. Ocean
> ecosystems provide important goods and services to society, such as
> fisheries, pharmaceuticals, and waste processing, as well as the
> biogeochemical cycling of important elements and gases critical for
> life on Earth. The health and productivity of ocean ecosystems is
> intricately linked to the overall health of the Earth. But, ocean
> ecosystems are not static in time and can be perturbed by natural and
> anthropogenic factors. We need to understand the impacts and feedbacks
> influencing our changing marine ecosystems, from small coastal reefs
> and beaches to the vast pelagic sea.
>
> Overwhelmingly, the most important source of energy for oceanic food
> webs is that derived from the sun through the process of
> photosynthesis. Marine food webs use this energy from primary
> production to drive the cycle of life in the sea from which humankind
> benefits in what we call \"ecosystem goods and services\". Quantifying
> primary production (the net result of plant photosynthesis) and its
> variability is critical for understanding and observing ocean
> ecosystems.
>
> The diverse community of plants and animals that comprise ocean
> ecosystems control the functioning of an ecosystem. Highly productive
> ocean ecosystems, such as coastal upwelling environments, tend to have
> food webs with fewer links between energy stored by primary producers
> and higher trophic levels, like fish and humans. Less productive, open
> ocean food webs are comparatively much more complex, with a wide
> diversity of plants and animals playing important roles in the cycling
> and recycling of energy and nutrients. Understanding this diversity -
> details of what types of animals and plants - is critical for devising
> effective strategies to manage marine resources and services, such as
> fisheries or carbon sequestration.
>
> ![](media/image17.jpeg){width="1.6283464566929133in"
> height="2.572834645669291in"}Ocean ecosystems can also be thought of
> as organic entities that interact with a dynamic physical environment.
> Changes in ocean currents, temperature, salinity, light, and chemical
> environments of the upper ocean often have critical roles on the
> structure, function, persistence and resilience of an ecosystem.
> Disturbances play a central role in ecosystem behavior and vary from
> episodic events, such as storms, to gradual changes, such as shifts in
> global ocean temperature or acidity (pH). Linking disturbance
> phenomenon to ecosystem changes represents a significant challenge for
> current and future generations of scientists.

### What We Know and Need to Learn About Ocean Ecosystems

> ![](media/image18.jpeg){width="3.0in"
> height="1.5043307086614173in"}Satellite-based global distributions of
> ocean chlorophyll concentration and initial assessments of how they
> change in time have now been realized through three highly successful
> NASA missions: CZCS, SeaWiFS, and MODIS. These missions are all based
> on the concept that by accurately measuring small variations in the
> visible radiance reflected from the Earth, changes in ocean
> phytoplankton pigment concentrations or chlorophyll can be detected.
> Chlorophyll is found in all plants and is literally at the core of
> photosynthesis. Regions of the ocean with high chlorophyll
> concentrations are, to a first approximation, more productive than
> those with low concentrations. NASA\'s Ocean Biology and
> Biogeochemistry science community has developed the first-ever,
> space-based biogeographical analyses of ocean ecosystems, and is
> deeply engaged in studying their relation to the physical processes of
> the sea and their links to other parts of the Earth\'s system.
>
> Using these missions to observe temporal changes in the chlorophyll
> distribution, we have learned how ocean ecosystems respond to
> environmental change. These changes can be rapid, driven by eddies and
> wind-driven upwelling, or they can happen at seasonal time scales in
> response to changes in the ocean\'s surface mixed layer or other
> seasonal phenomena. In the North Atlantic (Figure below), the
> northward progression of calm weather in the spring leads to a bloom
> of phytoplankton across the entire basin. Yet the process is not the
> same every year. Understanding and predicting why this process changes
> requires knowledge of the physical environment (see Mixed Layer Depth
> requirement below). From only a few years of such observations, it is
> already clear that oceanic ecosystems vary from year to year and from
> region to region. Studying long-term changes in the planet requires
> careful assessment of these year-to-year regional changes, to ensure
> recognition and interpretation of long-term trends.

![](media/image19.jpeg){width="2.267361111111111in"
height="0.9715277777777778in"}![](media/image20.jpeg){width="2.3069444444444445in"
height="0.96875in"}![](media/image21.jpeg){width="2.2583333333333333in"
height="0.9986111111111111in"}![](media/image22.jpeg){width="2.31875in"
height="1.0104166666666667in"}

*The progression of the North Atlantic Bloom during the months of spring
and early summer of 1999 as seen in monthly SeaWiFS ocean color imagery.
Note the northward progression of the bloom as seen in the elevated
chlorophyll concentrations from March to June of 1999.*

> Assessing decadal-scale changes in the ocean\'s biosphere using the
> global CZCS, SeaWiFS, and MODIS chlorophyll concentrations has been
> hindered by significant differences in instrument characteristics and
> observations that necessitate incongruent processing strategies. The
> lesson learned from these experiences is that engineering is not
> enough to satisfy decadal-scale Earth system science questions. Along
> with technological developments, it is imperative to have a robust and
> consistent strategy for interrelating observations between missions.
>
> Importantly, chlorophyll concentration is only one measure of one
> property of ocean ecosystems. It simply is not enough. To understand
> and predict change, we need to remotely assess the diversity of
> ecosystems, as well as their physiological status and productivity and
> how they function to provide goods and services to humankind. There
> will be limitations of what can be observed from space, but there is
> more to ocean ecosystems than simply a measure of \"greenness".
> Observing this will require new technologies and will present new
> challenges to overcome.

Next Steps

> To develop a predictive understanding of global ocean ecosystem
> health, productivity, biodiversity, and trophic dynamics, we first
> need to observe these factors and processes, and develop conceptual
> models of how the system works. Remote techniques are the only viable
> tools we have to do this on global scales, because field observations
> from the ground are simply too costly and not synoptic. Making these
> measurements using remote technologies will require continued
> technical and scientific advances that build upon the knowledge
> accumulated since the 1970\'s.
>
> First, we need to determine ecosystem biomass over ocean scales. The
> chlorophyll content of phytoplankton cells can change in response to
> light, temperature, and nutrient stresses. Non-living compounds like
> dissolved organic materials can also mask the signals of chlorophyll
> and effectively alter the color of the ocean. Accurate scientific
> assessments of phytoplankton biomass require understanding and routine
> observation of competing optical signals. All these observations must
> be accurate enough to enable the assessment of changes over timescales
> of decades.
>
> Second, the biodiversity of ocean ecosystems must be quantified and
> monitored over time. To first order, this can be done by quantifying
> concentrations of important phytoplankton functional groups (e.g.,
> diatoms, coccolithophorids, cyanobacteria (*Trichodesmium sp.)*,
> etc.). Other relevant measures of community diversity are
> determinations of particle size spectra, abundances of different
> phytoplankton size classes and the relative contribution that
> non-living materials make to the absorption and scattering of light.
> We also need to develop the capability to predict the impact of these
> changes on higher trophic levels through ecosystem models.
>
> Third, to understand how elements cycle within the oceans and how much
> food and energy can be provided by ocean ecosystems, we need to
> accurately assess marine primary production and monitor indices of
> ecosystem health. Models for assessing rates of productivity are
> available, but they have large uncertainties and lack reasonable
> predictive skill. A strategy is needed to implement the merging of
> satellite data into *in situ* observing systems, research
> observatories, and numerical models. In particular, novel space-based
> approaches that include lidar technologies are required to measure the
> physiological status and health of marine ecosystems.
>
> Ecosystems are dynamic entities in an ever-changing ocean. To
> understand them, we must fully understand the physical environment in
> which they live and with which they interact. Satellite measurements
> of incident solar radiation and its spectral components, mixed layer
> depth, sea surface height, vector winds, sea surface temperature, and
> surface currents are all important complements to biologically-focused
> missions in a comprehensive ocean program aimed at understanding
> complex global marine ecosystems.

"The biodiversity is one of the bigger wealths of the planet, and
nevertheless the least recognized as such." - E. O. Wilson, 1992

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## How do Carbon and Other Elements Transition between Ocean Pools and Pass through the Earth System, and How do These Biogeochemical Fluxes Impact the Ocean and Earth\'s Climate over Time? {#how-do-carbon-and-other-elements-transition-between-ocean-pools-and-pass-through-the-earth-system-and-how-do-these-biogeochemical-fluxes-impact-the-ocean-and-earths-climate-over-time .Style-Heading-2-+-Light-Blue}

The Challenge

> ![](media/image23.png){width="2.1805555555555554in"
> height="1.5208333333333333in"}
>
> ![](media/image24.png){width="2.0in" height="1.3751968503937009in"}
>
> Key biogeochemical elements include carbon, oxygen, nitrogen,
> phosphorous, silicon, sulfur, and iron. Their cycling involves complex
> exchanges between multiple ocean reservoirs and between the ocean,
> atmosphere and land. While quantifying elemental standing stocks is
> essential, it is not enough. In all cases, information is also needed
> on transformation *rates*. These 'rate' terms may take the form of a
> physical process, such as the airborne deposition and upwelling of
> iron, or they may be a biological process such as photosynthesis.
> Fortunately, knowledge of a few rates and multiple stocks allows many
> of the missing pieces in elemental cycles to be worked out.
>
> The carbon cycle is the most thoroughly studied of the ocean elemental
> cycles. Many components of the ocean carbon cycle have properties that
> allow their estimation from space, such as: total particulate organic
> carbon (POC), particulate inorganic carbon (PIC), dissolved inorganic
> carbon (DIC) \[i.e., various groups use SST and Chlorophyll *a* to
> estimate pCO~2~\] and net primary production (NPP). Whereas others,
> including dissolved organic carbon (DOC) and phytoplankton carbon
> biomass, are not yet adequately constrained and await new missions
> with advanced satellite technologies. Still some carbon cycle
> attributes cannot be directly detected from space (e.g., export flux)
> and must be deduced from surface properties, field measurements, and
> models.
>
> ![](media/image25.png){width="2.5in"
> height="2.4755905511811025in"}Each key ocean biogeochemical cycle is
> influenced by humans. In all cases, material transport from land to
> the oceans via rivers and estuarine input is important, but it is
> particularly critical for phosphorous and nitrogen cycles (roughly
> half of the 'new' nitrogen entering the oceans each year is now
> traceable to human sources). Atmosphere-ocean feedbacks are also
> prominent in elemental cycles, such as the carbon cycle through
> air-sea CO~2~ exchange and the iron cycle through Aeolian dust
> deposition. Elemental cycles in the ocean are also tightly coupled to
> climate. An effective observational strategy for ocean biogeochemistry
> thus requires the integration of ocean-focused missions with
> supporting atmospheric and

terrestrial components.

### What We Know and Need to Learn About Ocean Elemental Cycles

> Following the launch of CZCS, phytoplankton chlorophyll concentration
> has been the primary property targeted by NASA's ocean color missions.
> Technologies have largely focused on supporting 'wavelength ratio'
> algorithms derived empirically from field measurements and wholly
> reliant on the so-called 'bio-optical assumption', which assumes that
> all optically active constituents covary with chlorophyll in a
> globally consistent manner. From these measurements, our understanding
> of global phytoplankton dynamics, distributions, and responses to
> climate forcings has taken a quantum leap forward. In many respects,
> NASA's ocean color missions provided the single greatest advance in
> biological oceanography during the 20^th^ century. By viewing the
> oceans from space, we now estimate ocean productivity as roughly equal
> to terrestrial net production, although uncertainties around both
> estimates remain large (\> 30% at a minimum). Ocean color data also
> improved our understanding of carbon cycling in coastal zones and over
> continental margins, allowed the first global quantification of
> colored dissolved organic matter (CDOM), and documented global ocean
> responses to El Niño-Southern Oscillation (ENSO) cycles. Time-series
> analyses have established that ocean biogeochemical cycles are not at
> steady state, contrary to assumptions held as truth for nearly 100
> years. Some ocean features exhibit distinct trends linked to changes
> in sea surface temperature (SST) and ocean circulation.
>
> ![](media/image26.jpeg){width="3.1515748031496065in"
> height="4.218897637795275in"}Along with the many great discoveries
> provided from satellite observations, we have also learned how very
> little we really did (and still do!) understand about the oceans. One
> thing that is clear is that the 'bio-optical assumption' is not
> universally valid. Consequently, we now know that an evolution in
> observational capabilities is necessary. Fortunately, paths for
> utilizing such new information are well underway, including the
> simultaneous separation of multiple in-water constituents through
> 'spectral matching' approaches, the derivation of particulate carbon
> pools through retrievals of light scattering coefficients, the
> detection of physiological variability through satellite-derived
> chlorophyll:carbon ratios, and the distinction of iron-limited
> populations through unique fluorescence characteristics.
>
> The past few decades have also witnessed significant advances in
> coupled ocean circulation-ecosystem models. These models provide a
> platform for implementing new functional relationships between
> physical and biological processes both on local and global scales.
> They also provide prognostic capabilities to forecast changes in ocean
> processes well into the future. Remote sensing data can contribute
> critical information for advancing coupled model performance, but in
> many cases the geophysical parameters derived from space are not
> directly matched to key model components. Through the expansion of
> ocean products enabled by new satellite observations, remote sensing
> can assume a more prominent role in future model development.

### Next Steps

> Quantifying, monitoring, and predicting changes in ocean elemental
> cycles and their interactions with atmospheric and terrestrial systems
> requires information on stock sizes and key transformation rates.
> Advanced ocean remote sensing missions must address atmospheric
> correction issues associated with absorbing aerosols, improve the
> separation of optically active in-water constituents, enable a
> broad-scale characterization of unique ecosystem conditions (e.g.,
> separating iron- and nitrogen-limited waters), and provide appropriate
> space and time scale observations for interdisciplinary approaches to
> quantify elemental fluxes at the land-ocean interface.
>
> As ocean remote sensing science evolves from simple empirical
> algorithms to higher-order spectral models, measurements must be made
> with higher accuracy and precision. Consequently, future observations
> must include extensive pre-launch sensor characterizations and
> post-launch calibration capabilities. Improved approaches for
> atmospheric correction of imagery will require information on
> absorbing aerosol type, thickness, and vertical distribution. New
> strategies are needed to improve corrections over coastal 'bright
> waters' as well, where water leaving radiance contributions can be
> significant in near-infrared atmospheric correction bands. In some
> cases, dedicated sensors for atmospheric measurements and integrated
> efforts between the ocean and atmospheric science communities will be
> necessary to realize ocean research goals.
>
> While unparalleled water leaving radiance accuracies are fundamental
> to future remote sensing observations, they are not enough. Classic
> 'ocean color' bands were not optimized nor calibrated, for
> semi-analytic spectral algorithms and are not adequate for fully
> resolving the complexities of ocean water and optical properties.
> Enhanced measurement capabilities are necessary, both in spectral
> range and spectral resolution. Active approaches (i.e., lidar) can
> provide independent measures of critical elemental stocks. For
> example, lidar sub-surface light scattering profiles can yield
> important information on particle biomass abundance. Focused studies
> on the land-ocean interface and adjacent coastal waters will also
> require increased spatial resolution (\<250 m).
>
> ![](media/image27.png){width="3.3715277777777777in"
> height="0.7298611111111111in"}
>
> *LIDAR track from offshore to onshore, near Wallops Island, VA. Note
> the entrainment of sediment in the current from the shoal. Courtesy of
> F. Hoge, http://aol.wff.nasa.gov/*
>
> ![](media/image28.jpeg){width="2.443700787401575in"
> height="3.1838582677165355in"}
>
> Global, and more detailed regional, descriptions of key
> transformational rates is perhaps the greatest challenge in resolving
> elemental cycles. Observations of central physical forcings (e.g.,
> dust deposition, incident light, mixed layer depth, SST, etc.) can
> function as a basis for mechanistic models of rate terms or simply may
> provide important supporting information. For the carbon cycle, the
> most accessible transformation rate is net primary production, but it
> requires the description of physiological variability. Passive remote
> sensing retrievals of phytoplankton chlorophyll:carbon ratios provide
> one approach to assessing physiological variability. Effectively
> implementing such an index requires additional information on regional
> differences in the nature of nutrient stress (e.g., iron vs.
> nitrogen).
>
> Quantifying ocean elemental cycles, however, will require more
> information than can be gleaned from remote sensing data alone.
> Accordingly, all national and many international science agencies are
> developing programs to contribute uniquely to the problem. Integrating
> NASA's effort with these concurrent efforts and field programs (e.g.,
> the North American Carbon Program (NACP), the Ocean Research
> Interactive Observatory Networks (ORION), the National Ecological
> Observatory Network (NEON), and the Global Ocean Observing System
> (GOOS)) is essential to the success of the Ocean Biology and
> Biogeochemistry program. This interaction must entail not only shared
> observational capabilities and data sets, but also synergistic
> contributions to the development of Earth system models.

[]{#refheading___toc136168901 .anchor}***How (and Why) is the Diversity
and Geographical Distribution of Coastal Marine Habitats Changing, and
What are the Implications for the Well-Being of Human Society?***

### The Challenge

> Coastal habitats are among the most complex and diverse environments
> on Earth, providing substantial socio-economic benefits. They extend
> from above the spring high tide-limit to shallow regions of the
> continental shelves, and include coastal watersheds, dunes and wooded
> coastal areas, beaches and cliffs, wetlands, estuaries, barrier
> islands, and shallow submerged lands like seagrass beds, kelp beds,
> and coral reefs. More than \$1 trillion of the U.S.'s annual gross
> domestic product (GDP) is generated within the relatively narrow strip
> of land immediately adjacent to the coast. Services provided by
> coastal ecosystems include purification of water through nutrient
> recycling, sediment storage, shoreline protection, and supplying
> habitat and food for migratory and resident animals, as well as
> humans. Coastal habitats provide important biological and mineral
> resources for the pharmaceutical, oil, gas, and sand and gravel
> industries, and support key fisheries and maritime operations,
> including housing our ports. Every year, hundreds of millions of
> visitors flock to the Earth's coasts to enjoy the many pleasures the
> ocean affords. Yet we still know little about the variety of coastal
> habitats and resources in them.
>
> Human pressures, combined with changes in climate, threaten the
> sustainability of our coastal resources. Pollution, subsidence, sea
> level rise, development, and the building of structures that alter
> sediment flow all contribute to the threat. Land is being developed
> for housing at more than twice the rate of population growth, and
> poorly planned growth reduces and fragments fish and wildlife habitats
> and can alter sedimentation rates and flows. With the loss of the
> nation's wetlands, shorelines are becoming more vulnerable to erosion,
> saltwater is intruding into freshwater environments, flooding is on
> the rise, water quality is being degraded, and wildlife habitat is
> being fragmented or lost. Fishing also exerts pressures on coastal
> habitats.
>
> ![](media/image29.jpeg){width="3.9722222222222223in"
> height="1.6513888888888888in"}
>
> *This image collected with the airborne NASA AVIRIS sensor shows a
> wide diversity in coastal habitats off southwestern Puerto Rico (image
> courtesy of James Goodman, University of Puerto Rico)*
>
> We can improve our way of life by managing our growth and by
> mitigating impacts of climate change. This requires understanding
> coastal habitats and how they are interconnected and linked to inland
> activities. The ecosystem-based management of coastal habitats is
> necessary and requires interdisciplinary scientific understanding and
> forward-looking technologies. NASA is the only agency capable of
> leading an accelerated research and advanced engineering program on
> coastal habitats, which require space-based technologies because of
> their extension along the edges of all continents and their important
> contribution to developing global coastal ocean observing systems.

### What We Know and Need to Learn About Coastal Habitats

![](media/image30.wmf){width="3.8043307086614173in"
height="3.511023622047244in"}

> Coastal zones are exposed to storms, waves and currents, and inputs of
> sediment, nutrients and organic matter through rivers. Rivers
> integrate the effects of land use change across watersheds. Coastal
> lands may be submerged and exposed by the action of tides and
> wind-driven surges. These forces vary continuously leading to rapid
> changes in ocean temperature, salinity, nutrient load, light,
> bathymetry, bottom types and land run-off. This, in turn, leads to
> great variety in biological diversity and productivity of coastal
> habitats. These habitats harbor interconnected ecosystems where
>
> ocean and air currents transfer energy, biogenic material (larvae,
> pathogens), sediments and other materials between components. While we
> are beginning to understand the complexity of coastal habitats, we
> have only just begun to predict rates of connectivity among habitats
> and their impacts.
>
> ![](media/image31.wmf){width="3.1244094488188976in"
> height="2.764566929133858in"}
>
> Traditional methods are inadequate to study the great variety of
> coastal habitats and their large geographic extent. Water depth is a
> defining habitat factor of these complex three dimensional
> environments, yet we have accurate bathymetric charts for only a small
> fraction of our nation\'s coastal waters. New potential exists for
> developing detailed bathymetric and benthic substrate maps for clear
> coastal waters from space-based and suborbital platforms using a
> combination of multispectral and lidar imaging technologies.
>
> ![](media/image32.wmf){width="3.25in"
> height="2.6515748031496065in"}The very high productivity of many
> coastal waters reflects contributions from phytoplankton as well as
> macroalgae (e.g., kelp) and sea grasses, and is supported by frequent
> enrichments of nutrients and organic carbon from rivers and
> resuspension. Indeed the extent and character of freshwater inputs
> often defines coastal habitat type. The composition of organic
> materials, shallow and variably reflective benthic substrates,
> resuspended materials, and highly diverse aerosol distributions
> characteristic of coastal zones make retrievals of ocean properties
> from passive ocean color measurements difficult at best. *The limited
> spectral measurements from the current suite of ocean color sensors
> are clearly inadequate for coastal zone remote sensing research*.
> Fluorescence bands on the NASA MODIS sensors now provide some
> advantage for discriminating phytoplankton blooms from other colored
> phenomena, such as river plumes, and in combination with measurements
> in the near-ultraviolet (360 -- 400 nm) may provide better
> descriptions of in-water constituents than currently available through
> traditional blue-green visible bands. These new developments further
> emphasize the importance of expanding observations in spectral range
> and resolution for applications in optically complex coastal waters.
>
> The riverine flux of water, sediment, nutrients and other materials to
> continental margins depends largely on the climatology of each
> watershed. These materials significantly impact coastal habitats, yet
> we still don\'t understand their timing, extent or the frequency of
> runoff events. Ultimately, it is critical that we understand the range
> of processes through which rivers, land and coastal habitats are
> coupled. To date, no comprehensive studies have examined the effects
> of watershed processes and oceanography on coastal habitats over
> continental or basin scales. Such efforts would require repeated
> synoptic assessments that allow discrimination between habitat
> elements.

### Next Steps

> A range of space-based observations, suborbital systems, and models
> need to be developed over the next 25 years to advance our
> understanding of coastal habitats. Foremost is the requirement to
> obtain frequent and synoptic observations of small-scale phenomena in
> both aquatic and adjacent land environments. Developing a workforce
> capable of processing and using these advanced observing technologies
> and products is also critical. Significant progress can be made by
> establishing effective links between research and decision-support
> tools for coastal managers and policy makers.
>
> Coastal remote sensing presents significant technological challenges.
> A key issue is effective discrimination of biogeochemical constituents
> of the water and seafloor (e.g., colored dissolved organic matter,
> phytoplankton concentration and composition, suspended sediments,
> bottom type) and physical properties (e.g., temperature, salinity,
> wind, circulation, bathymetry, light attenuation). Changes in these
> properties must be resolved over long-term and short-term (daily to
> weekly) periods, at medium spatial resolution (10 to 100 m), and
> within the topographic and bathymetric regime of coastal habitats
> (watershed to about 20 m depth). Model development must proceed in
> parallel and at equivalent scales to the new observations. Together
> these advanced capabilities will lead to new understandings on
> linkages between lower and higher trophic levels, including living
> marine resources used commercially, for recreation, or cultural
> purposes. NASA\'s research on coastal habitats will contribute
> significantly to, and benefit from, efforts conducted through the
> National Science Foundation\'s ORION program and the coastal
> components of the Integrated Ocean Observing System (IOOS), the
> Climate Change Science Program (CCSP) and the Global Earth
> Observations System of Systems (GEOSS).
>
> Historical oceanographic satellite sensors have limited utility in
> studying or monitoring coastal zones, in part because of their coarse
> ground resolution and limited spectral resolution and range. Refining
> ground resolution, expanding the spectral resolution and range, and
> addressing significant absorbing aerosol contamination issues together
> create an enormous challenge for accurately distinguish coastal ocean
> components and characteristics from remote sensing imagery.
> Landsat-class sensors (NASA's Landsat, France's SPOT, Space Imaging,
> Inc.'s Ikonos, GEOEye's Quikbird, etc.) provide higher spatial
> resolution, but have limited sensitivity and are unable to detect the
> subtle changes in reflectance linked to the geophysical properties of
> interest.
>
> While the problem is tractable, scientific advances in coastal aquatic
> environments will require innovative techniques and diverse
> approaches. An effective strategy must incorporate active and
> multispectral passive observations, and both global and local
> measurement capabilities. Advanced sensors require expanded
> capabilities beyond the NPOESS Preparatory Project (NPP) and National
> Polar-orbiting Operational Environmental Satellite System (NPOESS)
> missions, with an aim toward Landsat- or Advanced Spaceborne Thermal
> Emission and reflection Radiometer (ASTER)-class observation frequency
> and spatial resolution. Coastal observing capabilities include sensors
> that can dwell on dark targets or illuminate them with advanced lidar.
> Observations need to be consistent and calibrated, accessible, and
> well-documented.

***When it comes to managing our oceans, we\'re in shallow water.***

> \- *Admiral James D. Watkins, Chair, U.S. Commission on Ocean Policy,
> and career submarine officer*

## How do Hazards and Pollutants Impact the Hydrography and Biology of the Coastal Zone? How do they affect us, and can we Mitigate their Effects?  {#how-do-hazards-and-pollutants-impact-the-hydrography-and-biology-of-the-coastal-zone-how-do-they-affect-us-and-can-we-mitigate-their-effects .Style-Heading-2-+-Light-Blue}

### The Challenge

> To date, environmental hazard monitoring has primarily focused on
> land-based hazards, such as volcanoes, droughts, floods, landslides,
> and fires, and their impacts on land surfaces. Environmental hazards,
> however, have tremendous impacts on the world's oceans, the
> communities residing along coastlines and the economies they support.
> ![](media/image33.jpeg){width="2.1798611111111112in"
> height="1.8423611111111111in"}Recent years have witnessed
> record-breaking natural hazards impacting coastal zones. Worldwide,
> the number of intense Category 4 and 5 hurricanes has nearly doubled
> since the 1970s. The year 2005 marked a new record for the number of
> tropical cyclones forming in the Atlantic during a single year.
> Hurricane Wilma, which struck the Yucatan Peninsula in October 2005,
> was the most powerful storm ever observed with winds of 280 km/hr (175
> mph). Hurricane Rita (Figure, left) had strengthened into the third
> most powerful hurricane on record before it weakened and struck the
> Texas/Louisiana border in September 2005. The tsunami that devastated
> over a dozen Asian nations in December 2004 resulted from one of the
> largest earthquake in recorded history. Large and infrequent or
> *acute* events alter the landscape of coastline, impact water quality,
> devastate coastal habitats, and greatly impact organisms within the
> coastal zone as well as communities residing along the coasts.
>
> ![](media/image34.jpeg){width="3.65625in"
> height="2.7423611111111112in"}
>
> *Hurricane Katrina resulted in the worst natural disaster in U.S.
> history (Photo: S. Lohrenz)*
>
> Although less dramatic, long-term changes to ocean properties are also
> hazardous to marine ecosystems. *Chronic* hazards include sea level
> rise and incremental changes to ocean sea surface temperature, pH,
> salinity, and nutrient composition. All of these long term hazards
> alter marine habitats and food webs in ways that can be measured.
> Changes in sea surface temperature (a remotely detected variable), for
> example, can impact upwelling processes that bring nutrients necessary
> for photosynthesis from depth to the sea surface.
> ![](media/image35.jpeg){width="1.9270833333333333in"
> height="2.90625in"} Uptake of anthropogenic CO~2~ by the ocean changes
> seawater chemistry and projections indicate that the corresponding
> drop in surface ocean pH will be lower than it has been for more than
> five million years. Increased acidity will cause mortality in marine
> organisms that calcify, including coccolithophores, foraminiferans,
> reef-building corals and planktonic pteropod molluscs. Eutrophication
> of coastal waters by high nutrient loads in runoff already causes low
> oxygen zones that kill fish and other marine life and may be related
> to blooms of harmful algae. *Chronic* changes such as these result in
> permanent and potentially catastrophic changes to marine life.

### What We Know and Need to Learn about Hazards and the Coastal Zone

> Many of the acute impacts of natural and anthropogenic hazards on
> coastal water quality and marine life occur from plumes of material
> either being re-suspended from the bottom or carried to the coast
> through runoff from land. The consequence of these transport processes
> is often a ![](media/image36.jpeg){width="2.6251968503937007in"
> height="1.1783464566929134in"}![](media/image37.png){width="2.6251968503937007in"
> height="1.183464566929134in"}decline in the growth or diversity of
> marine life. Re-suspension of sediments in coastal harbors, for
> example, can release toxic matter that has adsorbed to the sediment,
> thereby increasing the load of toxic chemicals in the water column.
> Re-suspended material influences light penetration in the water column
> and can inhibit growth of photosynthetic algae and seaweeds.
> Redistributed sediments can interfere with shipping channels. Runoff
> from land also introduces a variety of toxins, including oil, into
> nearshore waters. Glacial meltwater plumes in polar regions can alter
> productivity and the phytoplankton composition of surface water,
> subsequently impacting entire food webs. Plumes of harmful algae and
> "red tides" (which may or may not be harmful) are increasing along the
> coasts in response to a variety of environmental stressors.
>
> Satellite data are currently being used to track the course of
> tropical storms and hurricanes and document resulting coastal erosion
> and sediment re-suspension events in coastal zones. However, these
> methods are qualitative and only show impacts that can be observed
> visually from a true color image, such as the apparent extent and
> duration of a sediment plume. Better methods are required to
> accurately estimate the composition and/or concentration of materials
> within plumes and their dispersion over time. Quantitative models are
> also needed to characterize impacts of hazardous plumes on coastal
> processes. Most approaches for estimating sediment concentrations are
> highly empirical and site-specific, cannot differentiate different
> sediment constituents, and are not reliable under extreme conditions.
> Research is needed to integrate the various relevant measurements
> needed to understand intense algal bloom development and the
> propensity of these blooms to produce toxins. As storm surges erode
> coastlines, we also need rapid-assessment methods to identify the
> amount of eroded material and depth of flooded inland areas. Modeling
> flood water properties will require an understanding of the water's
> optical properties. Assessment of chronic hazards requires continuous
> observations that elucidate incremental changes in coastal conditions.
>
> Chronic shifts in basin-scale productivity have been observed from
> satellite ocean color measurements. For example, warming of the
> Eurasian landmass has been linked to enhanced upwelling and
> satellite-derived phytoplankton biomass in the Arabian Sea. Nutrients
> concentrations (e.g., inorganic nitrate) and air-sea carbon fluxes
> have been monitored at the sea surface through satellite-derived
> climatologies of ocean basins. These studies typically use empirical
> relationships between satellite-derived products, such as sea surface
> temperature, chlorophyll, and wind speed, and other biogeochemical
> parameters of interest. However, both acute and chronic changes to the
> world's oceans may significantly modify the relationships between
> these parameters. Large-scale changes in the oceans due to increased
> runoff of meltwater or increased warming, for example, may also cause
> the standard ocean color algorithms to become inaccurate.

**Next Steps**

> Quantifying sea level rise, coastal erosion, and plumes of suspended
> material, dense algae, or toxins requires higher temporal, spatial,
> and spectral resolution imagery than currently available. New
> satellite retrieval algorithms are needed that are not merely
> site-specific empirical regressions, but instead can accurately
> determine the quantity and composition of suspended materials, as well
> as be used to make inferences about relevant indicators that cannot be
> measured remotely. Improved atmospheric correction approaches must be
> developed to deal with significant amounts of near-infrared
> reflectance and absorbing aerosols common over coastal regions.
> Integrated modeling and data assimilation efforts will be required to
> tie together *in situ* measurements and diverse remote sensing data,
> such as sea surface temperature, vector winds, bathymetry, and
> delineation of coastal fronts and other surface phenomena (e.g., using
> Synthetic Aperture Radar). Rapid-assessment methods are needed in
> order to monitor and respond to episodic events and hazards along our
> coasts. Sensors that can potentially monitor beneath cloud cover
> (e.g., suborbital surveys from unmanned aerial vehicles) will provide
> a critical link to hazard assessment and development of response and
> mitigation strategies.
>
> Evaluating the impact of chronic hazards on marine ecosystems requires
> extensive and precise monitoring coupled with modeling efforts aimed
> at understanding how surface processes monitored from space can
> provide information on ocean chemistry, biology, and geology, both
> within the surface layer and at depth. Initial efforts have been
> undertaken to assess changes in ocean parameters due to alterations in
> the land, atmospheric, and oceanic environments from available
> satellite-derived products. However, the robustness of the empirical
> relationships used to estimate biogeochemical parameters has not been
> evaluated under different climate scenarios. A shift towards
> analytical approaches may allow us to infer changes in ocean biology
> and biogeochemistry better than empirical approaches. New satellite
> missions with enhanced spectral capabilities will be critical for
> advancing these efforts. Coupling in situ monitoring and ocean
> modeling with new satellite measurements will be necessary to address
> the chronic changes facing the ocean ecosystems. Collaborations with
> the National Science Foundation\'s ORION program and the coastal
> components of the IOOS and GEOSS may provide additional support for
> these efforts.

#  

# Recommendations for an Integrated Living Ocean Program 

> **T**he four core ***Science Questions*** encompass the foremost
> issues in ocean biology and biogeochemistry research. Within each, we
> have identified specific ***Next Steps*** that together constitute a
> broadly conceived program of measurements and supporting activities
> that will provide answers to the four science questions. The preceding
> section identified ***Observational Requirements*** for each question,
> many of which overlap multiple questions. For example, substantial
> progress can be made toward answering all four science questions by
> expanding the spectral range and wavelength resolution of global water
> leaving radiance measurements. These new data will allow separation of
> ecosystem components key to addressing all four science questions.
> Similarly, enhanced spatial (10 to 100 m ?) and temporal (sub-daily)
> resolution will contribute important information to answering these
> four science questions. Such overlaps allow the diversity of new
> measurement requirements to be consolidated into a tractable suite of
> seven specific ***Observational Strategies***:

1.  Global Sun-synchronous Hyperspectral Imaging Radiometer

2.  Global Geostationary Hyperspectral Imaging Radiometers

3.  Multi-Spectral High Spatial Resolution Imager

4.  Portable Sensors from Suborbital Platforms

5.  Variable Fluorescence Lidar

6.  Mixed Layer Depth and Illumination Sensor

7.  Ocean Particle Profiler and Aerosol Column Distributions

> Details on each of these observational strategies are provided in the
> following subsections, including recommended development activities
> for the immediate (1 -- 5 years), near-term (5 -- 10 years) and
> long-term (10 -- 25 years) time frames.
>
> Further, interdependencies exist among specific measurements. For
> example, the global and regional passive measurements of ocean
> radiances addressing all four science questions depend on coincident
> descriptions of atmospheric contributions to top-of-atmosphere
> radiances (including effects of aerosol type, thickness, and vertical
> distributions). Likewise, lidar-based surveys of subsurface particle
> scattering contribute little to the four science questions without
> coincident global ocean color data. Thus, the seven measurement
> capabilities listed above can be further packaged into a set of four
> overarching ***Mission Themes***:

**Recommended Mission Themes**

+-----------------------------------+-----------------------------------+
| 1.  *Global Separation of         | 3.  *Active Assessment of Plant   |
|     Optically Active and          |     Physiology and Composition*   |
|     Ecosystem Components          |                                   |
|     (advanced radiometry &        | 4.  *Mixed Layer Depth*           |
|     aerosol characterization)*    |                                   |
|                                   |                                   |
| 2.  *High Spatial and Temporal    |                                   |
|     Resolution Coastal*           |                                   |
+-----------------------------------+-----------------------------------+

> Each of these four **Mission Themes** represents a technology
> development line with a cohesive science focus and immediate,
> near-term, and long-term goals. A given **Mission Theme** can entail
> one or more sensors focused on the observational strategies listed
> above. Complementary aspects of the **Mission Themes** lead to a
> natural sequence in their execution, unfolding logically toward a
> complete observational capability. Thus, **Science Questions**
> identify **Observational Requirements*,*** which define
> **Observational Strategies**, which lead to **Mission Themes**, which
> define a recommended 25-year horizon of distinct **Satellite
> Missions**. This science-driven cascade from questions to missions is
> described in detail in the "Summary" section below.
>
> To support the recommended 25-year plan, NASA must build on its
> existing infrastructure and expand its capabilities in a systematic
> manner that matches the progression of science goals of NASA's
> mission. Given the multidisciplinary scope of this research, these
> activities will need to proceed in collaboration with other NASA Earth
> Science research programs, e.g., physical oceanography, terrestrial
> ecology and land cover, radiation sciences, and atmospheric
> composition, as well as other U.S. and international programs. In many
> cases, these other disciplines provide critical information for OBB
> satellite data processing, e.g., aerosol properties and spatial
> distributions. Indeed, more integrated measurement strategies are
> needed than what was realized in previous missions such as SeaWiFS and
> MODIS, as better integration will foster interdisciplinary science and
> information exchange. This was and still is a major goal of NASA Earth
> Observing System science (EOS), and new strategies for continuing this
> pursuit in an era of smaller missions must be conceived.
>
> The elements of this broader program are detailed in this section and
> include:

-   Observational Strategies (*the seven listed above*)

-   Supporting Measurements, Research and Modeling

-   Systematic Observations

-   Education/Public Outreach

> A successful program requires a balanced approach in each of these
> areas with mechanisms in place that allow developments to be
> integrated in a timely manner. For instance, future hyperspectral
> observations can only realize their scientific potential if the
> information systems, calibration, and validation capabilities (e.g., a
> comprehensive *in situ* program) are sufficiently robust and deployed.
> Furthermore, the observational systems envisioned, both satellite and
> *in situ*, often require technology developments that must be
> identified well in advance of when the on-orbit support systems are
> needed. The Mission Theme framework for future research in ocean
> biology and biogeochemistry must provide mechanisms for cross-talk
> between the four Themes, as well as the prioritization and sharing of
> resources, such as computational and field data systems. Similarly,
> activities of other NASA disciplines should be leveraged where
> appropriate and augmented if necessary to maximize the return on
> research investments (e.g., AERONET).
>
> NASA's Ocean Biology and Biogeochemistry Program has made great
> progress in Earth Science research over the past decade. Projects such
> as SeaWiFS, MODIS, and SIMBIOS have provided critical data sets and
> calibration and validation infrastructure. These missions and projects
> have also demonstrated how the international science communities can
> more effectively collaborate and use data from sensors in more
> interdisciplinary ways than previously envisioned (e.g., SeaWiFS data
> for terrestrial (NDVI) products). However, intersensor and
> interdisciplinary data fusion studies are rapidly having their full
> potential realized. At the same time, these projects are either
> completed (i.e., SIMBIOS) or beyond their prime mission lifetimes.
> Activities, approaches, and technologies developed to support these
> projects need to be revisited and revised if we are to further explore
> and understand the unseen world beneath the ocean's surface.
> Scientists have learned much about the ocean's role in the Earth
> System from previous and current on-orbit global missions, and seek to
> answer the next critical series of science questions using innovative
> technologies that will inspire the next generation of researchers.
>
> NASA seeks to build upon lessons learned from past missions. For
> instance, SeaWiFS and MODIS were designed to focus on the global ocean
> and the sensors were indeed found to function best within open ocean
> environments. These missions also produced a limited set of validated
> products, particularly chlorophyll-a. A major obstacle for ocean
> science developments is that available on-orbit and *in situ*
> instruments are obsolete, representing technology designs that are now
> older than 15 years. In the time since the launch of these missions,
> requirements to make high quality observations in coastal and global
> regions have been articulated by the science community and paralleled
> by technology developments for both active and passive sensors. We can
> make such improvements possible. While systems for quasi-operational
> sensors such as the Visible Infrared Imager/Radiometer Suite (VIIRS)
> on NPP and NPOESS may maintain the existing chlorophyll-a time series,
> VIIRS is not designed to address many of the science questions now
> being posed by researchers. New measurements from both Low Earth Orbit
> (LEO) and Geostationary Earth Orbit (GEO) are necessary, and the time
> to begin mission planning is now, otherwise we face a gap in the
> climate data record due to poor planning. Science discipline
> partnering on missions (e.g., ocean biology and biogeochemistry and
> radiation sciences) is possible and advantageous, but care must be
> taken not to substantially compromise science requirements and sensor
> performance in the processing.
>
> Advances in ocean remote sensing over the past two decades have been
> paralleled by advances in computational technologies and coupled
> models of atmospheric circulation, ocean biogeochemistry, and ocean
> dynamics. The supporting framework must enable partnering of the
> observational and modeling communities. Certainly, regional and global
> data can be used for model validation and data assimilation, and this
> is being pursued by the Global Modeling and Assimilation Office (GMAO)
> at NASA/GSFC, for instance. Additionally, the remote sensing science
> requirements and related field validation programs must be linked to
> requirements of the modeling community and can be augmented to provide
> additional data for model parameterizations. This is particularly
> important because of the difficulty in getting field data from many
> areas in the ocean, and requires the optimization of cruise planning
> and sampling for specific purposes.
>
> Finally, the missions recommended here are the result of questions
> posed based upon decades of scientific research. Many critical
> components of the ocean system remain unexplored, and will remain so
> beyond what can be accomplished from space-based observations. This
> does not mean that the accumulation of this knowledge is any less
> important to the NASA Ocean Biology and Biogeochemistry program.
> Instead, it requires that robust field and laboratory research efforts
> (beyond the previously stated requirements of a calibration /
> validation program) be an integral part of the NASA OBB program.
> Emerging science questions will come from a thorough understanding of
> the ocean biosphere. In some cases, this is most expediently achieved
> from *direct* observations and experimentation in the field and
> laboratory, rather than from the *remote* views achieved from space.
>
> In the following sections, the seven **Observational Strategies** are
> introduced along with timelines to address the measurement
> requirements for each of the four **Mission Themes**.
>
> Together these provide a prioritized view of science-driven
> observational capabilities, and the future of our program. Of foremost
> importance is the immediate development and launch of an advanced
> global ocean mission with high spectral resolution capabilities from
> the ultraviolet to near-infrared and (a) dedicated instrument(s) for
> characterizing absorbing aerosols (composition, thickness, height).
> This highest priority mission supports advances under all four science
> questions in a global manner, should be succeeded by similar but
> advanced missions throughout the 25 year horizon of this mission plan,
> and defines the first **Mission Theme** identified above (*Global
> Separation of Optically Active and Ecosystem Components*). The second
> mission priority for OBB science is (are) sensor(s) enabling high
> spatial and temporal coverage of global coastal regions. Instrument
> development and launch for this **Mission Theme** should occur within
> the near-term (5 -- 10 years) at the latest, if launches and platforms
> of opportunity are available or international coordination of sensors
> can occur. This global coastal-focused mission theme likewise entails
> sequence missions throughout the 25-year horizon and has a synergistic
> dependence on the global mission theme for information on absorbing
> aerosol distributions. The two remaining **Mission Themes** (*Active
> Assessment of Plant Physiology and Composition* and *Mixed Layer
> Depth*) are less well defined in technological approaches and
> requirements, and thus involve dedicated missions only in the
> long-term time frame (10 -- 25 years). These mission themes are
> focused on key observations augmenting the two top priority themes to
> enable the most comprehensive answers to the four science questions.
> Their contributions are thus dependent on at least a simultaneous
> advanced global mission, and as stand-alone missions offer little
> toward addressing the OBB science questions.

## Observational Strategies

### Global Hyperspectral Imaging Radiometer

> Quantification of phytoplankton biomass and primary production has
> always been a central objective of satellite ocean color missions like
> SeaWiFS and MODIS. The essential derived biological product of these
> missions has been chlorophyll (water-leaving radiances are the basis
> for higher order products like chlorophyll). In the late 1970's and
> early 1980's, the CZCS mission demonstrated basic approaches for
> atmospheric correction and pigment quantification. However, the CZCS
> sensor did not have a band(s) below 443 nm, which would make it
> possible to separate colored dissolved organic matter (CDOM) and
> chlorophyll, nor did it have the NIR bands required for accurate
> atmospheric corrections. SeaWiFS and MODIS incorporated a 412 nm band
> to facilitate this separation, as well as additional bands in the NIR.
> Reasons for not including other bands further into the UV included
> difficulties in calibrating the bands (in the laboratory and on orbit)
> and in the atmospheric correction (an extrapolation of the aerosol
> correction from the NIR). In the intervening 15+ years, detector
> technology and data processing methodologies have matured to a point
> that these are no longer such major limitations. By moving further
> into the UV, the divergence of the CDOM and chlorophyll absorption
> spectra becomes greater, making accurate separation of these
> substances more reliable.
>
> Molecular (Rayleigh radiance) and aerosol (particulate) scattering
> cause the atmosphere to contribute at least 90% of top of the
> atmosphere radiance over the ocean. This atmospheric contribution is
> also affected by absorption by gases (e.g., ozone and NO~2~) and
> aerosols (e.g., dust, smoke, and urban pollution). SeaWiFS and MODIS
> have used measurements in the NIR (765/748 and 865) to estimate
> aerosol radiance in the visible bands (after modeling for the Rayleigh
> radiances). This technique assumes that there is zero subsurface ocean
> reflectance in the NIR. This assumption is invalid in turbid or
> optically shallow water (coastal regimes), requiring the reflectance
> to be modeled. Studies using MODIS bands at longer NIR wavelengths
> where the absorption by water is much greater (roughly ten times) have
> demonstrated that atmospheric corrections over turbid coastal waters
> are feasible in the 1200-1700 nm range.
>
> As for the identification and correction of absorbing aerosols, no
> reliable method using the SeaWiFS and MODIS band sets has been
> developed to make accurate corrections without assuming a particular
> absorbing aerosol type and vertical distribution. Additional bands in
> the UV would be useful for at least flagging certain absorbing
> aerosols over the open ocean and a specific UV band at 317.5 nm would
> provide simultaneous ozone corrections. At present, high
> concentrations of dust and smoke are identified as clouds in the cloud
> masking, but low concentrations of dust, smoke, and pollution are not
> detected. Consequently, these conditions lead to erroneously low
> water-leaving radiances that are interpreted as high chlorophyll
> concentrations. Accurate atmospheric corrections are possible if
> aerosol properties are simultaneously measured with ocean color,
> including aerosol altitude and type. Advanced ocean missions must
> therefore include additional measurements beyond those of a
> radiometer, such as a profiling lidar, advanced polarimeter, or both.
>
> Just as sensor technology has progressed, developments in marine
> optics and reflectance inversion algorithms have opened the door for a
> much broader suite of derived products. These new products map
> directly to requirements outlined above for our four ***Science
> Questions***. Additional spectral information in the UV and visible
> (particularly between 555 and 665) not only allow for better
> separation of pigments, but also separation of phytoplankton
> functional groups such as carbon exporters (diatoms), nitrogen fixers
> (*Trichodesmium sp.*), calcium carbonate producers (coccolithophores),
> and the microbial loop organisms (*Prochlorococcus sp.*). The more
> spectral information provided to the inversion algorithms, the more
> accurate and diverse the retrievals of absorption and backscattering
> coefficients. Recent instrument design studies have shown that the
> SeaWiFS and MODIS multi-band designs cannot be easily expanded to meet
> both the new spectral requirements (especially between 300 and 800 nm)
> and the necessary design criteria specified in the box below. These
> broader mission criteria enable greater flexibility in implementing
> new retrieval algorithms and data processing methodologies
> post-launch, unlike the more restrictive fixed-band designs of SeaWiFS
> and MODIS. Spectral resolution of an advanced radiometer should be
> around 5 nm to allow flexibility in aggregation of data into 10-20 nm
> band widths from the UV through the visible. These broader bandwidth
> aggregations allow accurate characterization of key ocean constituents
> in global open ocean regions where absorption spectra have relatively
> broad features, while the higher-resolution capability enables
> detection of unique functional group properties and improved
> separation of constituents in optically complex global coastal
> regions. The enhanced spectral capabilities also enable derivation and
> optimization of fluorescence retrievals, which are particularly
> beneficial in quantifying phytoplankton chlorophyll biomass during
> phytoplankton blooms and in coastal waters. NIR aggregate bands of an
> advanced radiometer can be broader (20-50 nm), depending on the
> proximity of atmospheric absorption features, which improves SNRs.
>
> The data collection strategy for an advanced global mission should
> allow downlink of the full spatial and spectral resolution data,
> rather than performing band aggregation or spatial sub-sampling on the
> spacecraft. Accordingly, high bandwidth downlinks and efficient
> lossless data compression will be necessary. High latitude ground
> station(s) can ameliorate data rate issues by providing several
> contacts per day. Temporal sampling requirements for missions like
> SeaWiFS and MODIS included "2-day" global coverage, meaning that all
> areas in the global ocean would be observed at least every other day
> (in the absence of cloud cover).
>
> One other consideration for future sensors is the continuation of long
> time series, i.e., SeaWiFS, MODIS, VIIRS, etc., of key data products,
> e.g., water-leaving radiances and chlorophyll-a, which are consistent
> from mission to mission. While improvements in the chlorophyll-a
> product will continue, some future improvements may not be achievable
> using the SeaWiFS and MODIS bands, yet a "continuity" chlorophyll
> product is desirable for decadal change studies. In fact, the band
> differences between SeaWiFS and MODIS have resulted in some
> differences in the chlorophyll-a products. For example, MODIS does not
> have the 510 nm band that SeaWiFS has, resulting in different
> chlorophyll-a values at high concentrations where the SeaWiFS
> algorithm uses a 510/555 nm band ratio. A hyperspectral sensor would
> avoid this problem by allowing the multispectral sensor bands to be
> reconstructed, thus allowing the replication of historical products.

Proposed Implementation Timeline:

### Geostationary Hyperspectral Imaging Radiometers 

Coastal oceans play an important role in mediating exchange and
transformation of materials between land and ocean ecosystems. Rates of
primary production in coastal waters are often an order of magnitude
higher than for open ocean waters and consequently can play an important
role in global biogeochemical cycles of carbon and other elements.
Recent work has shown that continental margins are responsible for
greater than 40% of the carbon sequestration in the ocean. While the
advanced global mission described above will provide much valuable
information on coastal margin processes worldwide, critical deficiencies
will still exist in our understanding of these processes due to
inadequate observing capabilities, particularly at the interface of the
oceanic, terrestrial and atmospheric domains. These deficiencies will be
addressed by the following observational strategies

![](media/image38.png){width="2.940944881889764in"
height="2.5866141732283463in"}Coastal zones are difficult to observe as
they exhibit extreme environmental heterogeneity in both space and time.
Coastal processes and phenomena (e.g., tides, eddies, phytoplankton
blooms) are dynamic and ephemeral, often exhibiting considerable
variability on sub-diurnal time scales. Episodic forcing associated with
wind, freshwater run-off, and interactions with mesoscale circulation
features can exert profound impacts on coastal ecosystems on relatively
short time scales. Temporal evolution of sporadic phenomena such as
sediment resuspension and transport cannot be resolved with existing
satellite capabilities. Multiple sensor-looks per day are required to
capture these changes and, can additionally remove tidal aliasing and
mitigate cloud cover issues.

The optical complexity of coastal waters necessitates innovative
approaches to improve the ability to characterize biogeochemical
distributions and processes in coastal regimes. Our ability to
characterize change in the coastal oceans is limited by our capacity to
distinguish the complex mixture of in-water optical constituents
(including phytoplankton pigments, particulate and dissolved organic
carbon, and total suspended matter (TSM)) and by difficulties associated
with atmospheric correction issues that can be severe over coastal
waters. River runoff, suspended sediments, colored dissolved organic
matter (CDOM), phytoplankton blooms and shallow water bottom reflectance
all add to the complexity of the optical signal in coastal waters.
Detailed radiometric inversions are required to discriminate among these
water column constituents in the face of the competing signals from
atmospheric constituents (e.g., complex aerosols of continental origin).
As detailed above for the advanced global mission, current ocean color
sensors provide inadequate spectral range and resolution. Continuous
spectral coverage from at least 350nm to 1050nm is required, providing
crucial UV, SWIR and fluorescence bands, with a spectral sample of at
least 5 nm.

> In coastal environments, phytoplankton composition and food web
> structure can vary dramatically. Understanding for these ecosystems
> requires rigorous classification and quantification techniques for
> different phytoplankton functional groups, such a, diatoms,
> coccolithophorids, and cyanobacteria (e.g., *Trichodesmium)*.
> Algorithms have been successfully used to retrieve unique
> phytoplankton absorption spectra from hyperspectral reflectance
> spectra and these methods have shown promise for discriminating and
> quantifying harmful algal blooms in coastal waters. Information about
> phytoplankton size structure can also be derived from absorption
> spectra.

Coastal ecosystems are also spatially complex. Coastal phenomena occur
on scales of many tens of meters to many kilometers in horizontal
extent. Such spatial scales cannot be adequately resolved with the
current generation of ocean color satellite sensors, which generally
have a ground resolution on the order of 1 km.

As such, in order to better assess, understand and predict natural and
anthropogenic-driven variability in coastal zones, there is a need for
dedicated regional/coastal missions with high temporal coverage
(sub-diurnal), spectral resolution (\>20 bands with narrow bandwidth)
and spatial resolution (\< 1km). An effective approach for remote
observation of complex, rapidly evolving, coastal ocean biological and
biogeochemical properties will necessarily involve a hierarchical
approach involving multiple platforms and sensors, improved algorithms,
data fusion, and integration of observations with data assimilation and
numerical modeling.

With regard to the identified need for multiple platforms and sensors, a
constellation of ocean imagers with complementary capabilities and
specifications is required to adequately address the diverse
requirements of the global coastal research and applied user
communities; the temporal component may not be fully addressed by
implementation of a global hyperspectral imaging radiometer, as above,
simply due to revisit issues. In this context, an international
constellation of geostationary (GEO) hyperspectral imaging radiometers
is a crucial need to provide global coastal coverage with the necessary
high temporal revisits. NASA envisions contributing a sensor/platform
(alone or as part of a mission of opportunity partnership with another
U.S. federal agency) to this international effort to provide coverage of
the global coastal oceans, joining other regional efforts such as the
planned Geostationary Ocean Colour Imager (GOCI) on the COMS-1 platform
from South Korea. If it is not possible to work with the international
research community and space agencies to entice the international space
agencies planning GEO missions to coordinate the locations, orbits, and
data distribution, then a key alternative would be a single
geostationary sensor and mission with a precessing orbit would provide
researchers the ability to study short duration (\<1-5 day) processes in
low and mid-latitude global waters.

The constellation of regional GEO ocean imagers in turn needs to be part
of a broader constellation with LEO ocean imagers as also called for by
this plan, with broad, lower resolution global ocean coverage provided
by a LEO hyperspectral imaging radiometer as described above, and a very
high spatial resolution coastal zone imager as described below .
Leveraging the inherent capabilities of both LEO and GEO orbits, a
constellation of this type would provide nested global, regional, and
local coastal and open ocean coverage with both high spatial and
temporal resolution. This crucial nested ocean observing capability
needs to be quickly built out and then sustained over time (ensuring
smooth transition from R&D to operational agencies), with different
international partners contributing individual elements, coordinating
standards and cal/val strategies, sharing data, and avoiding
gaps/redundancies under the auspices of a Global Earth Observing System
of Systems (GEOSS).

Proposed Implementation Timeline:

###   {#section-13 .unnumbered}

### 3. Multi-Spectral High Spatial Resolution Imager 

Nearshore ecosystems and habitats are at the boundary between land and
ocean and are continuously subject to both natural and anthropogenic
sources of change. Change in these nearshore environments can be caused
by land-ocean interaction processes such as river runoff and coastal
erosion and easily altered by human activities. Runoff from land can
include a variety of toxins, including oil, into the nearshore waters.
Re-suspension of sediments in coastal harbors, for example, can release
toxic materials increasing the load of toxic chemicals in the water
column. These materials can also influence light penetration in the
water column inhibiting the growth of photosynthetic algae and seaweeds.
Nearshore ecosystems are also unique as organisms can act to structure
the environment and provide habitat for diverse communities. Examples of
habitat forming species include coral reefs, kelp beds, mangrove swamps,
algal mats and sea grass beds. Many of the same considerations presented
here pertain to upland riparian habitats which are hydrologically
connected to the coastal ocean.

![](media/image39.jpeg){width="5.058333333333334in"
height="1.6861111111111111in"}

The remote assessment of nearshore environments is inherently difficult
as the spatial scales over which these ecological communities and
habitats are organized range from a couple of meters to many kilometers.
To examine these processes, one must employ new tools made to deal with
the difficulties involved with the passive measurements of ocean color,
but now at spatial scales several hundred times smaller. One way to
achieve these requirements is to implement a high spatial resolution,
multi-spectral imager capable of achieving typical ocean color SNR
levels. This high spectral resolution ocean color imagery would have
many distinct wavebands from the UV through the NIR (including natural
fluorescence bands), provide accurate atmospheric correction, high
spatial resolution (to less than 10 m), allow rapid repeat coverage of a
given site and the capability to follow a coastline (or river), stare at
a given location and adjust its mission in response to clouds. These
requirements provide a trade space from which future high spatial
resolution ocean color missions will be developed.

Proposed Implementation Timeline:

### 4.Portable Sensors from Suborbital Platforms {#portable-sensors-from-suborbital-platforms .unnumbered}

> Imagery with spatial resolution of meters or less is critical for
> mapping and tracking fine-scale features along coastal margins,
> including river plumes, flooded land regions, and seafloor features.
> Hazardous and episodic events require repeat sampling on the order of
> hours and not days or weeks, and require an imaging platform that can
> be used under cloud cover. Inland lakes, rivers, and coastal estuaries
> are also difficult to monitor at spatial scales available from
> space-based sensors. Sometimes, the most effective approach is **not**
> to sample from space orbiting platforms but from suborbital
> elevations.
>
> Portable sensors flown on aircraft or unmanned aerial vehicles (UAV's)
> provide a critical sampling niche distinct from satellite-borne
> sensors that is particularly well suited for coastal applications and
> ice research. NASA has long been the leader in developing and
> deploying sub-orbital remote sensing platforms. Airborne sensors can
> sample at fine spatial scales (meters), have minimal atmospheric
> correction issues due to low altitude flights, can operate under
> clouds and with nearly unlimited repeat coverage, and are effective
> platforms for high-resolution active sensors (e.g., lidar). UAV flight
> lines and scanning geometries can also be oriented to optimize
> retrievals (e.g., avoid sun glint) and their range can be greatly
> expanded by launching from ships. .
>
> UAVs can be used to support weather forecasting, hazard and coastal
> water quality assessment, inland flooding, coastline topography
> mapping, and harbor and shipping lane management. Two different
> prototype sensors with demonstrated utility are coastal lidars and
> imaging spectroscopy. Portable coastal lidars are an important tool
> for mapping vertical and horizontal topographic features along the
> coastal zone at spatial resolutions far surpassing
> satellite-measurements. These lidars can also differentiate seafloor
> properties in shallow water based on bottom brightness and spatial
> roughness. Measurements made by NASA's Experimental Advanced Airborne
> Research Lidar (EAARL) have an elevation accuracy of \<10 cm and
> horizontal accuracy of 40 cm and have been successfully used to map
> bathymetric features, beach erosion, coral reefs, and coastal
> vegetation. EAARL is a prototype for portable lidar sensors that could
> be deployed along coastlines to monitor temporal events, such as beach
> erosion or breaching.
>
> ![](media/image40.jpeg){width="3.1798611111111112in"
> height="2.342361111111111in"}
>
> Portable imaging spectrometers, such as NASA's Airborne
> Visible/Infrared Imaging Spectrometer (AVIRIS) and the Portable
> Hyperspectral Imager for Low Light Spectroscopy (PHILLS), provide the
> ability to monitor dense algal blooms or red tides, bathymetry, and
> seafloor features. Imaging spectroscopy has powerful applications for
> both habitat and hazard monitoring in coastal regions. PHILLS-type
> sensors allow operation under low-light conditions and provide high
> signal-to-noise data over a wide dynamic range. PHILLS has been used
> to map shallow water bathymetry and bottom seagrass habitats in the
> Bahamas Banks both before and after Hurricane Floyd. The AVIRIS sensor
> was designed for land targets, but has also been successfully deployed
> in a variety of coastal regimes. For example, AVIRIS imagery has been
> successfully employed to study dense algal blooms or red tides in
> Monterey Bay.

![](media/image41.jpeg){width="1.3464566929133859in"
height="1.4515748031496063in"}![](media/image42.jpeg){width="1.2834645669291338in"
height="1.4429133858267718in"}

![](media/image43.png){width="1.4381889763779527in"
height="1.8681102362204725in"}![](media/image44.jpeg){width="1.3291338582677166in"
height="1.8751968503937009in"}

> Measurements from portable sensors flown from suborbital platforms
> will greatly enhance our ability to monitor and respond to changes in
> the dynamic and heavily populated coastal zone. Moreover, the
> fine-scale resolution will be critical for studying inland waterways
> and assessing the extent and depth of inland flooding. Repeat surveys
> on hourly or shorter time scales can aid in mitigating hazards or be
> useful for adaptive sampling of ship-based ocean or limnological
> research. The UAV platform will be portable and allow for aerial
> surveys with a variety of different detectors and sensors. This will
> facilitate development and testing of new sensor technology that could
> be considered for future satellite missions and algorithm development.

Proposed Implementation Timeline:

###   {#section-14 .unnumbered}

### 5.Fluorescence Lidar

![](media/image45.jpeg){width="3.0in" height="4.0in"}

> Quantifying phytoplankton growth rates is an essential aspect of ocean
> productivity modeling. Unfortunately, phytoplankton growth rates are
> not directly detectable from space. However, changes in phytoplankton
> growth rate are associated with altered levels of 'cell greenness'.
> This 'greenness' response appears to behave in a consistent manner
> under a variety of environmental conditions, although a few stresses
> create unique behaviors . One of these conditions is iron-limited
> growth in the presence of high macronutrient concentrations \[e.g.,
> High Nutrient, Low Chlorophyll (HNLC) environments\]. In HNLC regions,
> phytoplankton respond to iron stress by over-expressing pigment
> synthesis and then binding these pigments into non-functional protein
> complexes that can later be used to rapidly create active
> photosynthetic units in the event that new available iron is
> encountered.
>
> One consequence of the low-iron, high-macronutrient physiological
> response is that the enhanced pigment levels give phytoplankton a
> false appearance of high growth rates. This condition must therefore
> be accounted for in any remote sensing assessment of growth rate based
> on 'greenness' indices. A second consequence of this unique
> acclimation strategy is that the phytoplankton exhibit exceptionally
> high fluorescence yields (due to the photochemically incompetent
> nature of the special pigment-protein complexes). As a result, HNLC
> regions characteristically exhibit persistently low variable
> fluorescence values (F~v~/F~m~) and large nocturnal decreases in
> F~v~/F~m~.[^1] Remote sensing assessments of F~v~/F~m~ can thereby
> provide a means for globally defining HNLC conditions, monitoring
> temporal shifts in physiological province boundaries, and establishing
> functional links between new iron inputs (e.g., dust deposition
> events) and ecosystem responses.
>
> Variable fluorescence has been measured in the field for \> 20 years
> and recently, through NASA support, has been successfully demonstrated
> from aircraft. For space-based applications, the 'pump and probe'
> technique employed for these airborne tests will need to be modified
> to reduce lidar energy demands and to meet eye safety requirements.
> Technological approaches for solving these issues are already under
> development.
>
> Globally defining and monitoring physiological provinces through
> satellite variable fluorescence measurements will require
> distinguishing F~v~/F~m~ values between 0.10 and 0.65 to \~0.05 units.
> Product spatial resolution requirements are coarse (10 to 30 km),
> allowing aggregation of multiple lidar returns to improve signal to
> noise ratios. Measurements should be conducted both at midnight and at
> dawn to determine maximal F~v~/F~m~ and the relative nocturnal percent
> decrease in F~v~/F~m~ (both critical diagnostics). This approach would
> require two satellites and would also provide information on the
> degree of midday light inhibition of photosynthetic electron
> transport. The excitation laser wavelength must penetrate a wide range
> of ocean waters (e.g., 532 nm from a Nd:Yg laser) and be effectively
> absorbed by chlorophyll. Simultaneous Raman measurements at 651 nm are
> also required for baseline signal calibration. Additional capabilities
> for detected fluorescence at high spectral resolution (1-2 nm) would
> expand the utility of the lidar measurements by allowing detection of
> specific phytoplankton groups through taxon-specific fluorescence
> features.

Proposed Implementation Timeline:

###   {#section-15 .unnumbered}

### 6.Mixed Layer Depth and Illumination Sensor

> For almost all of the open sea, the upper layer of the ocean is well
> mixed due to air-sea exchanges of buoyancy and momentum. Within this
> well mixed zone, the vertical distribution of all physical, chemical
> and biological variables are homogenized. Oceanographers refer to this
> zone as the mixed layer and its depth is called the mixed layer depth
> (MLD). Knowledge of the MLD is essential for many branches of
> oceanography as it controls the depth range over which air-sea
> exchanges of heat and momentum are averaged over and it controls the
> depth range over which organisms and chemical constituents are mixed.
> Values of MLD can range from practically nothing to more than 500 m
> and it can vary on time scales from hours to seasons. Of particular
> importance are the large changes in MLD associated with the seasonal
> cycle of heating and cooling. From mid-latitudes to high latitudes,
> mixed layer depths can vary from several meters to many hundreds of
> meters over the seasonal cycle. This alters the depth range over which
> biological and biogeochemical constituents are found in the upper
> ocean -- and are sampled using satellite remote sensed technologies.
> Hence, knowledge of mixed layer depth and its temporal changes over
> all relevant space and time scales is critical for the NASA OBB
> program.

![](media/image46.jpeg){width="6.5in" height="2.2708333333333335in"}

Monthly mean mixed layer depth climatology from hydrographic profile
observations for January (left panel) and July (right panel). Analysis
from de Boyer Montégut et al. \[2004\] (JGR-Oceans). Note that monthly
mean MLD values range from 10 to more than 500 m.

> Primary production cannot occur without light and there exist a host
> of other biological and biogeochemical processes that are similarly
> regulated by the flux and spectral quality of available light. The
> depth of the mixed layer -- along with the optical clarity of the
> mixed layer and the light flux at the sea surface -- are the first
> order determinants of the amount of light available to drive marine
> photoprocesses. Thus, the goal of assessment of mixed layer depth
> should be integrated with that for determining available light (both
> magnitude and spectral quality) that drives ocean biological and
> biogeochemical processes.
>
> Primary production in the surface mixed layer is not simply a function
> of light level, but also light quality. This spectral dependence of a
> biogeochemical flux is even more important for photochemical reactions
> such as the production of many radiatively important trace gases (CO,
> DMS, CO~2~, COS, etc.). For primary productivity, the spectral
> component is most important in the visible wavebands (PAR), while
> photochemical reactions are generally regulated by the flux of
> ultraviolet radiation. Energy budgets or 'solar heating' studies
> require knowledge of the entire solar spectrum and its diminishment
> within depth, including near infrared wavebands. Hence, the assessment
> of available radiation with the upper ocean mixed layer must consider
> the spectral quality of light.
>
> Success in many of NASA's Earth science objectives is dependent on the
> characterization of ocean mixed layer depths and their variability.
> This observational strategy aims to develop capabilities to assess
> mixed layer depth values and its variation over time and to determine
> mean light levels for this layer from the UV to NIR. The goal is to
> resolve MLD values and mixed layer light levels on horizontal scales
> of \<10 km and temporal scales from daily to decadal. Achieving these
> objectives globally requires accurate knowledge of three data
> quantities: MLD, incident irradiance, and spectral light attenuation.
> The various approaches outlined below evolve from a synthesis of
> current remote sensing and field observations in a numerical modeling
> framework to the development of potentially new remote sensing
> technology.
>
> Fortunately, two of the necessary pieces are already largely in place;
> global maps of incident light fluxes in the PAR and UV bands and
> models relating remote sensing products to the spectral transmission
> of solar radiation through the water column. Assimilation of field
> observations into data assimilation models of the physical ocean
> environment can provide a first order treatment of the third piece:
> MLD. Climatological assessments of mixed layer depth can be derived
> from hydrographic data and a capacity for determining MLD is well
> underway in development of operational oceanographic data systems.
> Another path involves the application of remotely sensed geophysical
> parameters (e.g., winds, heat fluxes, E-P, currents, SSH, SSS, etc) in
> the 1-D modeling of MLD. Here, 1-D mixed layer models are driven using
> appropriate air-sea exchange factors to obtain the time evolution of
> MLD driven only by remote sensing data sets. A difficulty remains that
> these data sources are not routinely synthesized to produce data
> products on the proper space and time scales. The synthesis of
> available data and forecast products is the first step in this
> observational strategy.
>
> Alternatives for remotely assessing MLD have not been well
> investigated yet. Evaluating empirical relationships between MLD and
> biological (e.g., phytoplankton Chl:C ratios) or chemical (CDOM or
> other remote sensible photochemical products) stocks may be one way to
> get at MLD from space-based observations. Here, regional assessments
> of the dynamic relationships among particular ocean optical properties
> and mixed layer light levels are used to solve for the required mixed
> layer depth. New research is required to determine the validity and
> general applicability of this approach. This approach may involve
> active techniques for directly measuring MLD from space. For example,
> laser emission/excitation spectroscopy could be developed to determine
> upper ocean concentrations of rapidly evolving photochemical species.
> By knowing the light driven kinetics of this chemical species and
> examining differences in its concentrations at different times of day,
> estimates of MLD may be derived. Clearly, this is an area where
> technical advancements are needed.

Proposed Implementation Timeline:

###   {#section-16 .unnumbered}

### 7.Ocean Particle Profiler and Aerosol Column Distributions 

> Vertical changes in light scattering properties measured through the
> atmosphere and into the ocean from a space-based lidar can provide
> important new information for solving major ocean carbon and
> biogeochemistry science questions. Future missions targeting retrieval
> of geophysical parameters related to ocean elemental cycles through
> measurements of water-leaving radiances are critically dependent on
> accurate atmospheric corrections. Accounting for the contribution of
> absorbing aerosols to top-of-atmosphere radiances is particularly
> important and requires information on their vertical distributions as
> well as total optical thickness. Lidar measurements, both ground-based
> (e.g., Micropulse) and space-based (e.g., GLAS), have been shown to
> provide information on vertical aerosol structure at a resolution well
> beyond that necessary for ocean applications (\<0.5 km). Lidar aerosol
> profiling measurements simultaneous with passive radiometric data will
> enable unsurpassed atmospheric corrections and consequently vastly
> improved ocean geophysical parameters.
>
> In addition to aerosol assessments, lidar measurements can provide an
> independent, active measure of subsurface light scattering properties
> that can be utilized to constrain parameters in spectral matching
> models applied to passive radiometer data. Subsurface light scattering
> can be measured at 532 nm and 355 nm, the second and third doublings
> of a Nd:Yg laser. Demonstrations of the technique have been repeatedly
> conducted from airborne platforms and have also been accomplished from
> space during the 1994 LITE experiments on the Space Shuttle. For
> retrieval of light scattering coefficients (m^-1^), subsurface
> profiles with a minimum of two distinct depths are necessary
> (additional depths preferable). Radiative transfer modeling and
> observational data indicate that with an 100 mJ eye-safe Nd:Yg laser
> at an altitude of 600 km, sufficient subsurface scattering values can
> be retrieved to \>15 m in clear ocean waters and to 5 meters in turbid
> coastal waters. To cover this full range of optical conditions,
> therefore, space-based measurements will require 1 -- 2 m vertical
> resolution and a lidar angle of incidence of 15^o^ relative to nadir
> (to avoid detector saturation at the surface).

Proposed Implementation Timeline:

## 

## 

## 

## 

## 

## 

## 

## 

## 

## 

## 

## 

## 

## 

## 

## 

## 

## 

## Supporting In Situ & Space-Based Measurements 

> Simply stated, the determination of ocean biological and
> biogeochemical quantities from low earth orbit has proven to be a
> difficult task. More than 90% of the passive optical signal measured
> on-orbit is derived from atmospheric scattering and is not the light
> emitted from the ocean. Hence, satellite ocean color observations need
> to accurately determine a very small ocean signal from a nearly
> overwhelming atmospheric one. Moreover, the signals associated with
> long-term trends can be very, very small making the accurate detection
> of long term changes especially difficult. Most of the proposed
> observational strategies, with the exception of suborbital surveys,
> involve delicate optical instruments that are launched into orbit by
> massive rockets and subjected to huge accelerations and vibrations and
> a hostile space environment. These factors compromise the validity of
> pre-launch calibrations for processing the resulting data streams.
>
> Clearly, the proposed measurement strategies require an in situ
> observation program aimed at providing vicarious calibration of the
> orbiting instrumentation, validating the quality of the on-going
> observations and providing a path of improving the quality and utility
> of the space-based measurements. This requires an in situ
> observational program linked to the satellite-based science program
> and a calibration/validation (or cal/val) program similar to the
> SIMBIOS program conducted by NASA and its international partners. To
> contribute to this kind of cal/val activity, one must:

-   accurately sample relevant observables,

-   make these observations across a wide range of biological and
    biogeochemical provinces,

-   relate the in situ observations to known community measurement
    standards,

-   provide these in situ data to a centralized data center where the
    data sets are synthesized into global data sets and compared with
    satellite observations,

-   compare vicarious instrument calibration results with on-orbit
    methods (such as lunar or solar viewing) and

-   push the envelope of what can be measured and how well these
    observations can be made.

> This requires continued investment in coordinated field observations,
> new instrumentation aimed to support present and future satellite
> observables, the production and dissemination of calibration standards
> for all investigators, and the free, open, and easy access of all data
> collected in support of the cal/val program.
>
> The ocean biology and biogeochemistry program must insure that the
> proper context is available for assessing change. For example,
> ecosystems respond to ecological disturbances over scales ranging from
> hours to decades. We need to characterize and understand sources of
> disturbance simultaneously with our direct OBB measurements. This
> requires a host of supporting measurements that are traditionally used
> in other fields. Supporting space-based, physical oceanographic
> measurements include sea surface temperature, sea level, vector winds,
> surface waves and salinity. Similarly for NASA OBB investigators
> working in polar regions, knowledge of the extent, thickness and
> duration of sea ice and terrestrial ice sheets are extremely important
> for interpreting their data sets. In coastal environments, knowledge
> of nearshore bathymetry and land/ocean interactions are important.
> Some of these observations can be made from space or sub-orbital
> platforms (UAVs) using passive radiometry, Synthetic Aperture Radar
> (SAR) or lidar techniques. Other useful non-oceanographic, space-borne
> observations include aerosol distributions and composition, mineral
> dust deposition and greenhouse gas concentrations, such as carbon
> dioxide. Continuity of these important supporting measurements (as
> well as others not mentioned here in the interest of space) is
> extremely important to the NASA OBB program. A broad suite of in situ
> measurements are also needed to complement and extend the utility of
> these space-based measurements, particularly to characterize important
> ecological parameters which can not be measured directly from space,
> or else measures at depth. These are anticipated to be collected at
> least in part through ongoing GOOS/IOOS efforts as well as the
> developing ORION Program.
>
> **Table: Examples of Supporting Space-Based Measurements**

+-----------------------+-----------------------+-----------------------+
| Supporting            | OBB Program Use       | Existing & Planned    |
| Measurement           |                       | Missions              |
+-----------------------+-----------------------+-----------------------+
| Sea surface           | Oceanographic context | AVHRR, VIIRS, TMI     |
| temperature           |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Sea surface height    | Oceanographic context | JASON-1, GFO, ERS-2   |
+-----------------------+-----------------------+-----------------------+
| Sea ice cover &       | Oceanographic context | AMSR-E, RadarSat, ERS |
| thickness             | in polar regions      |                       |
+-----------------------+-----------------------+-----------------------+
| Sea surface salinity  | Oceanographic context | Aquarius              |
+-----------------------+-----------------------+-----------------------+
| Vector winds          | Wind forcing          | QuikScat              |
+-----------------------+-----------------------+-----------------------+
| River discharge and   | Land-ocean            | SAR, Radar Altimetry  |
| plume extent          | interactions          |                       |
+-----------------------+-----------------------+-----------------------+
| Atmospheric column    | Air-sea CO~2~ fluxes  | OCO                   |
| CO~2~ concentration   |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Aerosol type &        | Mineral dust          | MODIS, CALIPSO, GLORY |
| abundance             | abundances &          |                       |
| distributions         | deposition            |                       |
+-----------------------+-----------------------+-----------------------+
| UV radiation          | Ecosystem forcing,    | TOMS                  |
|                       |                       |                       |
|                       | Atmospheric           |                       |
|                       | correction            |                       |
+-----------------------+-----------------------+-----------------------+

## 

## 

## Systematic Observations

> Analyses of continuous, high quality time series of Earth observations
> are critical to detail natural or anthropogenic climate variability
> and change taking place within the Earth System. However, for these
> analyses to take place, careful mission planning is essential that
> embraces continuity of remotely-sensed observations for climate
> research, as well as sensor data inter-comparison and data product
> merging to produce and maintain continuous key product time series.
> Critical climate data products vary depending on the science questions
> being addressed, but stringent on-board and in situ calibration
> requirements (e.g., measurement errors) must be addressed for any
> remotely sensed property to be sufficient for climate research.
> Several space-based sensors currently meet these requirements for
> ocean biology and biogeochemical research, including SeaWiFS and MODIS
> on Aqua.
>
> Both SeaWiFS and MODIS produce a phytoplankton chlorophyll data
> product, which has enabled improved understanding and prediction of
> phenomena such as the El Nino / Southern Oscillation events, which
> impacts fisheries throughout the Pacific. Other higher level data
> products, such as phytoplankton primary production, are also critical
> for understanding the long-term role of ocean biology in the global
> biogeochemical cycling of carbon and other elements within the earth
> system. Critical questions include:

-   Which satellite-based data products must be maintained as systematic
    observations to create time-series records of essential ocean
    biology and biogeochemical variables?

-   How do we ensure that a continued and overlapping sequence of
    space-based sensors are launched and operational such that an
    uninterrupted global data time-series is maintained beyond prime
    mission lifetime of the SeaWiFS and MODIS sensors?

-   How will continuity of the new science-critical measurements
    proposed within this plan be achieved?

> ![](media/image47.png){width="3.140277777777778in"
> height="1.9784722222222222in"}NASA has a responsibility to provide
> continuity of space-based research. This continuity is critical for
> oceanographers (and Earth scientists) if we are to continue our
> mission to understand and protect the home planet. Opportunities may
> be available with other U.S. Federal agencies, international space
> agency partners, and the commercial sector, but this budget and
> science planning must be carried out long in advance to prevent data
> gaps, something the ocean biology and biogeochemical research
> community now face. While VIIRS may provide continuity of the
> SeaWiFS-type biological observations beginning in the 2009 timeframe,
> the VIIRS data will not provide the next generation of space-based
> observations to address the science questions outlined in this plan.
>
> A strategic plan must be in place to consider the continuity of
> space-based ocean biology and biogeochemical observations in parallel
> with other key property measurements of the Earth Science disciplines,
> including physical oceanography (sea surface temperature, sea surface
> height), atmospheric composition and radiation sciences (atmospheric
> temperature profiles), land cover/land use change (land surface
> temperature and terrestrial primary productivity), and others. While
> these measurements are critical to understanding processes in the open
> ocean and coastal areas, they are also primary observations for
> understanding atmospheric and terrestrial processes and must be
> maintained. Without them, our capability to understand and predict
> both natural and man-made events and impacts on a changing Earth will
> cease.

## Research, Analysis and Modeling 

> The proposed future exploration of Earth's oceans can lead to
> discoveries that enable basic research to address practical issues
> facing society today. Past decades of research based on measurements
> from historical missions have defined a path for the next generation
> of ocean biology and biogeochemical studies from space. Current
> sensors continue to contribute toward Earth System research questions,
> but they have limitations. It is NASA's mission to facilitate research
> and planning to properly usher in the next generation of satellite
> sensors and inspire the next generation of researchers and explorers.
> Basic research in ocean biology and biogeochemistry at NASA, as well
> as interdisciplinary studies among other Earth Science fields has
> supported and led to the ideas contained in this plan.
>
> Prior to a satellite being launched, funds are typically needed to
> characterize a sensor in the laboratory and ensure the behavior of the
> sensor on orbit will be understood by the mission operations team.
> While mission operations and data analysis funding is critical to make
> the raw sensor data usable by stakeholders, funds must be available to
> use the data in basic research by the broad science community.
> Analyses of space-based and in situ data must follow the launch of any
> satellite or sensor. Scientists should have the opportunity to
> diversify their research pursuits in order to enhance understanding
> and protection of the Earth. Funds should be available for sensor
> concept development and assessment prior to and during mission
> development. As data from an on orbit sensor are collected, quality
> controlled, and archived for analysis (including data product
> algorithm validation), an interface with the modeling community must
> exist to facilitate assimilation and modeling. This is particularly
> important within the Earth System Modeling Framework.
>
> As NASA's Modeling, Analysis, and Prediction program grows in scope,
> it is critical to ensure that the ecological, biogeochemical, climate
> and other modeling communities are aware of the ongoing efforts and
> have access to facilities to properly enable effective collaborations.
> Earth System Scientists must have a vision to develop both coastal and
> global ocean ecological and biogeochemical models, and link them to
> the a common framework to better understand the Earth System as a
> whole. At the same time, we must recognize the shortcomings in
> modeling parameters and address these knowledge gaps with new sensors
> and measurements, as proposed here. Only through carefully planned
> collaboration and funding profiles can the modeling community succeed
> in effectively using the future science measurements proposed in this
> plan.
>
> Lastly, emphasizing measurements without a tightly coupled modeling
> component is a serious deficiency for any observational strategy. Many
> of the observables suggested in the previous sections (e.g., mixed
> layer depth, phytoplankton physiology) have direct counterparts in
> numerical models. These model estimates may be the result of a simple
> empirical relationship or one of many interacting components in a
> coupled ecosystem model, but they provide an important validation data
> set for testing observational data fields. In the very near future,
> data assimilation models will incorporate available satellite and
> other data to produce complete fields without time or space gaps for a
> wide variety of model variables. This will enable a wide array of
> science questions to be addressed using available satellite data.
> Further, data assimilation models may provide information better
> suited for resource managers and policy makers. This future requires a
> systematic and coordinated interdisciplinary approach to modeling
> ocean biological and biogeochemical processes.

## Education/Public Outreach 

The study of Ocean Biology and Biogeochemistry from space has yielded
important and vital scientific evidence for coupling between biological
and physical processes, between ocean and land, and between Earth
systems and human societies. The Space Act that established NASA charged
the agency with the responsibility to convey these discoveries to all
public audiences. NASA's goals for education across the agency are to:

-   Contribute to the development of the science, technology,
    engineering and mathematics (STEM) workforce in disciplines needed
    to achieve NASA's strategic goals through a portfolio of programs,

-   Attract and retain students in STEM disciplines through a
    progression of educational opportunities for students, teachers, and
    faculty, and

-   Build strategic partnerships and linkages between STEM formal and
    informal education providers that promote STEM literacy and
    awareness of NASA's mission.

The complexity of the Earth as a System presents unique opportunities
for STEM education that in many cases transcends the traditional
approach of teaching disciplinary science, i.e., Chemistry, Biology,
Physics, Geology, etc. Research in Earth System Science at NASA has
become increasingly multidisciplinary as well as increasingly focused on
the societal benefits of research results, demanding collaboration of
experts not only in traditional sciences, but also in social sciences,
computational sciences, informational technology, policy, etc. NASA must
continue efforts to encourage teaching of Earth System Science at all
levels of formal education, ensuring that students learn the nature and
importance of interactions between ocean and atmosphere and between
ocean and land margins, as well as how humans interact with and shape
the Earth's systems. Earth System Science provides many engaging
examples of broader science concepts recommended in the National Science
Education Standards, such a Constancy, Change, and Measurement, and
Systems, Order and Organization. NASA must play a key role in converting
Ocean Biology and Biogeochemistry knowledge into formal and informal
education settings.

The space observation program outlined in this document calls for a
comprehensive plan of hardware, observations, and models to provide the
tools necessary for prediction of change and responsible management of
ecosystems and resources. A qualified STEM workforce will be required
for success of this plan. NASA must continue to engage students and all
levels to the extent that many choose careers in STEM, while at the same
time promoting opportunities for students in underserved populations to
ensure that the diversity of the future workforce reflects national
demographics.

# Essential Partnerships 

NASA will continue to engage the international ocean science community
in developing and advancing priority science questions, articulating
observing requirements, pursuing partnerships in space-based sensor
development and measurement capabilities, and in *in situ* program
planning and development, particularly vicarious calibration and data
product validation activities. These efforts are facilitated through
such mechanisms as the NASA science and measurement team meetings, as
well through involvement with international planning and coordination
efforts, such as the Coastal and Ocean Themes of the Integrated Global
Observing Strategy (IGOS), as well as the International Ocean Color
Coordinating Group (IOCCG).

NASA participates in and contributes to various U.S. programs and
activities (e.g., Climate Change Science Program, U.S. Ocean Action Plan
committees, U.S. Integrated Earth Observation System), which
implementation of this plan will support. The National Oceanographic
Partnership Program (NOPP) helps to ensure that these contributions are
shared across other federal agencies as appropriate. Additionally, NASA
likewise partners with other U.S. agencies to promote operational
implementation of research and development capabilities and results as
deemed beneficial in support of user needs (as discussed further below).

In this manner this plan does not represent a stand-alone vision.
Implementation of this strategic plan will represent a significant
contribution in both research and technology development by NASA to an
overarching global ocean observing system, and furthermore as part of
the emerging Global Earth Observing System of Systems (GEOSS).
Fundamental scientific discoveries will result, as well as significant
benefits to society. In this broader observing system context this plan
will both complement and leverage other space and *in situ*-based
components of these systems, and as such broad partnership opportunities
abound as briefly highlighted below.

Ocean observing systems (including the Ocean Observatories Initiative
(OOI) and the Integrated Ocean Observing System (IOOS)), will be part of
the U.S. contribution to the Global Ocean Observing System (GOOS) and
part of the GEOSS, by definition will need to consist of *integrated*
observations from both *in situ* and remote assets. This OBB plan
contains a vision for novel, science-driven biological and
biogeochemical measurements of the open and coastal ocean from space
that will support fundamental research as well as enable new and
improved user-driven applications. As such, partnerships that help
bridge the space-based research and operational domains and facilitate
the transition of knowledge and capabilities between these communities
are envisioned; likewise cross-cutting community partnerships that
foster linkage of remote sensing and *in situ* observations.

In particular, these proposed OBB measurements will complement and help
significantly extend, enhance, and refine planned global operational
ocean color measurements from space (e.g., VIIRS on NPOESS), as well as
provide a way forward for the next generation of operational sensors
that will build on knowledge and insights gained from pathfinder
research sensors. A transfer of capabilities from NASA to respective
operational agencies could take place as part of a serial, phased
progression (e.g., similar to the "JASON" model for ocean surface
topography measurements). Similar needs, challenges and opportunities
exist for both continuity and ongoing improvement of supporting
calibration and validation capabilities. For example, operational
entities could potentially play the primary role in maintaining proven,
robust vicarious calibration systems to ensure calibration measurement
continuity, while research partners could in turn pursue development of
the next-generation systems that provide enhanced functionality and
performance to the extent that planned calibration measurements are of
interest to NASA's research efforts -- with these systems transitioned
over time as they become mature technologies, supporting corresponding
space-based measurements.

All of the space-based observational strategies put forward in this plan
need to be considered as part of a collaborative international
constellation of sensors/platforms that will improve our understanding
of ocean biology and biogeochemistry. This is particularly true with the
global hyperspectral imaging radiometer, coordination of which with
international space agencies respective global radiometric efforts may
provide higher spatial coverage of the global oceans, and therefore
improve predictive models. With regard to the geostationary,
hyperspectral imaging radiometer observing strategy, an international
constellation of regionally-focused imagers is a crucial need in order
to provide *global* coastal coverage with the necessary high temporal
revisits (IGOS, 2006). NASA could contribute one or more
sensors/platforms (alone or as part of a mission of opportunity
partnership with another U.S. federal or international space agency) to
an international global effort that will join other regional efforts
such as the planned Geostationary Ocean Colour Imager (GOCI) on the
COMS-1 platform from South Korea.

Crucial, nested ocean observing capabilities in partnership with the
international space research community and space agencies needs to be
quickly built out and then sustained over time (while ensuring smooth
transition from research to operational agencies), with different
national and international partners contributing individual elements,
coordinating standards and calibration/validation strategies, sharing
data, and avoiding measurement gaps/redundancies under the auspices of
the GEOSS.

Moving beyond a strictly disciplinary focus, there are opportunities to
partner with other Earth observing programs, particularly within NASA.
For example, there are significant benefits (and cost savings) to be
gained by working with NASA's Terrestrial Ecology Program scientists
toward implementation of a high resolution coastal imager that can also
be used to provide accurate vegetation cover assessments or resolve
functional type mixtures. Likewise, accurate measurement of aerosol
properties is a crucial element in support of ocean biological and
biogeochemical observations, affording partnering opportunities with the
atmospheric science community. Finally, Synthetic Aperture Radar (SAR)
can provide important geophysical and ecologically-relevant information
for ocean studies, and as such these needs should be considered in
conjunction with those of the solid Earth and cryospheric science
communities toward development of a mission that can satisfy these
multiple requirements.

Space-based measurements of the type identified in this plan will also
complement, extend (i.e., provide synoptic overview), and benefit (e.g.,
through validation, sub-surface measures) from ocean *in situ* point
observations acquired as part of the IOOS/GOOS and through the NSF
research-driven Ocean Research Interactive Observatory Networks (ORION)
program, particularly in complex, dynamic (e.g., coastal) regions.
Coordinated integration and assimilation of the remote and *in situ*
measurements will enable accurate, synoptic three-dimensional
characterizations of the ocean, contributing to an improved
understanding of global and coastal marine ecosystem dynamics and better
assessments and predictions of climate variability and change.

# Summary

Standing on the shore of our terrestrial home to gaze at a horizon
across the sea, we can begin to comprehend the shear vastness of the
global oceans and understand how they play such a pivotal role in the
functioning of our biosphere, the Earth. Under the shimmering or wavy
surface we see to the blackened depths of the abyss, there exists
another world teaming with life that remains largely undiscovered, but
upon which we utterly depend. From the large to the microscopic, the
plants and animals of our contemporary oceans each represent a pinnacle
in a four billion year old evolutionary competition, but our
understanding of their unique characteristics and roles in complex
marine ecosystems remains rudimentary at best. We nevertheless rely on
this diversity of organisms for producing oxygen that we breathe,
processing our wastes, cleaning the air, providing food and recreation,
and regulating climate. Yet the collapse of ecosystems under increasing
human pressures has made it abundantly clear that our marine resources
have a very finite resilience. These changes and those occurring from
natural environmental variability can have severe consequences on our
economy and quality of life. Understanding functional relationships
within the living ocean, along with ocean-land-atmosphere feedbacks,
represents a major challenge to the science community and one to which
NASA is particularly well poised to contribute greatly.

A primary goal of ocean biological science is the mechanistic
understanding and prediction of change in marine ecosystems, thereby
advancing descriptions of ocean biogeochemical cycles and enabling
informed national policy, improving resource management practices, and
decreasing threats to our economy, health, safety, and national
security. The global ocean is chronically under-sampled by field-based
measurements due to its enormous size, making space-based measurements
acquired by NASA and other national and international agencies
particularly vital. Since the launch of the first NASA ocean-color
sensor, CZCS, satellite-derived ocean biology products have truly led to
a 'Number range CHAPTERrenaissance' in our understanding of the global
ocean. However, our scientific and technological capabilities and
discoveries have greatly outpaced the evolution of satellite ocean
sensors. We now find ourselves in the unfortunate position where
achieving our national goals for ocean sciences is limited by obsolete
observational capabilities. The 25-year vision of the Ocean Biology and
Biogeochemistry Working Group is to address this issue head-on and to
head toward a capacity to functionally relate environmental change to
ecological variability through a new generation of ocean remote sensing
missions such that the consequences of a prolonged alteration or a new
environmental threat can be predicted.

Important events in ocean ecosystems occur on spatial scales ranging
from a few meters to thousands of kilometers and on time scales of hours
to decades. Accordingly, a comprehensive understanding of ecosystem
dynamics and their consequences requires an integration of observations
over a wide range of scales and from a diversity of platforms. Global
and regional satellite-based observations are absolutely essential to
successful ocean biology and biogeochemistry research program, as well
as local scale observations made in the laboratory and field. These
ground-based studies provide the functional relationships that form the
foundation of mechanistic ecosystem models. Already, our understanding
at this more fundamental process-oriented level challenges our remote
sensing capabilities and calls for a new generation of satellites and
sensors with greatly superior spectral range and resolution, a diversity
of spatial and temporal capabilities, and integration of active and
passive approaches that have cross-disciplinary applications with the
terrestrial and atmospheric science communities.

In this document, we identify four central scientific questions as top
priorities for NASA's Ocean Biology and Biogeochemistry Program for the
next 25 years. These four questions encompass outstanding research
issues that are of fundamental scientific importance, relevant to the
health, economy, and security of the nation, and are linked to ocean
properties that can be detected from space, and thus amenable to
advances through developments in new remote sensing tools.

The **four priority science questions for the NASA OBB program**
**are**:

-   **How are ocean ecosystems and the biodiversity they support
    influenced by climate or environmental variability and change, and
    how will these changes occur over time?**

-   **How do carbon and other elements transition between ocean pools
    and pass through the Earth System, and how do these biogeochemical
    fluxes impact the ocean and Earth\'s climate over time?**

-   **How (and why) is the diversity and geographical distribution of
    coastal marine habitats changing, and what are the implications for
    the well-being of human society?**

-   **How do hazards and pollutants impact the hydrography and biology
    of the coastal zone? How do they affect us, and can we mitigate
    their effects?**

These top priority questions should guide basic research and
observational objectives for ocean biology and biogeochemistry over the
coming decades. Specific expected accomplishments and benefits to the
Nation are outlined in this document for each top question and will be
realized as new measurements yield new understanding.

While cutting edge satellite missions are clearly the centerpiece and
unique contribution of NASA to Earth system science, it would be
difficult to overstress the importance of developing a broad
comprehensive research program that integrates remote sensing with
multi-level ground-based observations and modeling. Here, we outline an
ambitious plan of ocean science objectives and measurements that in a
variety of cases challenge our technological capabilities and in all
cases demand exceptional instrument characterization and calibration,
along with algorithm development and ground based validation of derived
geophysical parameters. Requisite to this program, therefore, is a
network of supporting field and laboratory studies involving
NASA-specific components and partnerships with other programs and
agencies. The new generation of ocean remote sensing missions will
deliver a suite of ecosystem and biogeochemical parameters carefully
aligned with key variables of ocean biogeochemical and ecosystem models.
Co-evolution of next generation models that fully utilize these new
observations is thus an integral aspect of the 25-year plan, and
includes significant investment in computational capabilities for
testing modeled geophysical fields and predictions.

The grand success of the first ocean color sensors (CZCS, SeaWiFS,
MODIS) is something NASA can be proud of, but it has had an important
negative consequence: *it has obfuscated the vision of the ocean science
community and science agencies*. 'Ocean color' has become synonymous
with the limited set of measurement wavebands observed with these 'first
generation' sensors and many are ready to 'close the book' on ocean
remote sensing and transition the science to 'operational' status.
Although we may have tapped the potential of this generation of sensors,
we have just begun to scratch the surface of the rich information still
waiting to be mined from ocean remote sensing measurements. The plan
recommended here for new space-based ocean observations represents a
maturation of ocean remote sensing science that learns from- and builds
upon the capabilities of 'first generation' sensors and allows NASA to
meet the emerging scientific challenges of coming decades.

The recommended plan involves a range of new measurements that build
toward a complementary measurement capability and map to four
observational components, each of which addresses one or more of the
four top priority questions listed above. The **four recommended mission
themes** are:

-   **Global separation of in-water constituents and advanced
    atmospheric corrections**

-   **High resolution coastal measurements**

-   **Plant physiology and functional composition**

-   **Mixed layer depth**

Specific strategies for each component over a 25 year time-frame are
divided into immediate (1 -- 5 years), near-term (5 -- 10 years), and
long-term (10 -- 25 years) goals. These recommendations are based on
science urgency, technology readiness, and supporting value for
subsequent measurement components. Thus, the four overarching science
questions of top priority define the suite of geophysical parameters
needed, which in turn dictates a succinct set and sequence of future
sensors and ocean missions outlined as observational measurement
strategies. The resultant time-resolved matrix of recommended missions
and their relation to science questions and societal benefits is
illustrated in the table on page 66 and the figure on page 64.

Over the next five years, the ***highest priority next generation ocean
science observing need is the development of a 2-instrument global
mission focused on the accurate separation of in-water constituents and
correction for aerosol contributions to top-of-atmosphere radiances***.
Such a mission addresses most of the urgent problems with current remote
sensing technologies and will make a significant contribution toward
addressing important aspects of all four top priority science questions
(table, p. 69). The mission also has strong synergistic potential for
contributing to science objectives within the terrestrial and
atmospheric disciplines. (To address urgent issues for ocean remote
sensing, the immediate launch of a single instrument satellite with an
advanced global-coverage radiometer may be an effective strategy if
budgeting does not currently permit a multi-sensor mission, with
addition of an aerosols platform following at a later date). Follow-on
global ocean-aerosol missions with advanced measurement capabilities
over the 5 to 25 year time-frame will further address outstanding issues
regarding monitoring and modeling of ecosystems and elemental cycles and
will contribute supporting observations for more focused, parallel ocean
missions.

![](media/image48.wmf){width="6.495833333333334in"
height="4.897916666666666in"}

A constellation of at least three geostationary platforms and sensors on
orbit are needed to survey biological and biogeochemical properties of
global coastal waters, or, alternatively, a single geostationary sensor
and mission with a precessing orbit would provide researchers the
ability to study short duration (\<1-5 day) processes in low and
mid-latitude global waters. All geostationary sensors would require high
temporal frequency, hyperspectral observations. In a constellation or
precessing orbit, a ***hyperspectral imaging radiometer*** would resolve
processes and phenomena and discriminate constituents on sub-daily time
scales and at 200 m resolution (or better) at nadir, utilizing parallel
Low-Earth-Orbit (LEO) aerosol distribution measurements for enhanced
atmospheric correction. Significant progress toward this goal can be
cost-effectively achieved in the next five to ten years either through
NASA (1) developing a mission and observing strategy that would satisfy
science requirements through the precessing orbit concept, (2)
contributing a dedicated mission to an international constellation, or
(3) leveraging a potential mission/platform of opportunity to an
international constellation.

Third, there is a need for a ***multi-spectral high spatial resolution
imager*** to observe coastal habitats and ecosystems on unprecedented
scales and accuracies. This mission may occur either on a dedicated
platform, via mission of opportunity or through a partnership within
NASA or other U.S. agencies. A good opportunity is the NASA/USGS Landsat
Data Continuity Mission (see the table on page 69). The ***deployment of
newly developed portable sensors on UAV's***, to provide detailed
information on nearshore coastal environments. In the 10 to 25 year
timeframe, there is a need to develop a constellation of imaging
spectrometers that will provide high spatial, temporal and spectral
resolution visible spectral radiance observations of coastal zones from
LEO, GEO, and/or MEO as well as sub-orbital platforms. These will
leverage complementary aerosol distribution measurements as above for
enhanced atmospheric corrections.

Also in the 10 to 25 year time frame, the recommended mission plan
includes continued development and deployment of suborbital sensors and
platforms, a sensor for measuring surface mixed layer depths and
illumination, and a lidar mission focused on characterizing provincial
distributions of specific growth limiting factors for phytoplankton. In
both cases, substantial technological developments and prototype testing
are required.

Ocean ecosystems, the habitats they occupy and create, and their
biogeochemical cycles are extremely complex. Remote sensing alone will
not unravel their secrets, dependencies, and feedbacks. A rigorous
program of basic field and laboratory research operating in parallel
with the new generation of ocean missions is essential. Synthesis of
observational data and applications toward biospheric monitoring and
prediction also requires substantial investments into advanced computing
capabilities. Development of new measurement technologies are likewise
accompanied by new requirements for computing, data storage, and
distribution capabilities. Thus, each of the four observational
components for ocean biology and biogeochemistry is accompanied by
requirements for augmented ground-based observational,
calibration-validation, and computing and modeling programs, along with
educational activities.

Today we find ourselves standing on the threshold of profound
breakthroughs in ocean biological sciences. Ushered in by the first
generation ocean satellite missions, we have within the past decade
realized major advances in our ability to resolve multiple in-water
constituents from remote sensing data, related these to key components
and rates within ocean ecosystems, and integrated this new information
into advanced prognostic models. Over this same period, we have also
seen tremendous technological developments that can enable the new
measurements necessary to address the remaining top priority ocean
science questions. Now we need to act. In the next 25 years, NASA can
take the lead in creating new observational capabilities for ocean
sciences that support our informed and careful stewardship of this blue
planet. In doing so, we will make great strides toward lifting the veil
on the 'Unseen World' and discover new knowledge of its functioning and
how to better manage and protect this resource for future generations.

![](media/image49.wmf){width="5.999305555555556in"
height="8.096527777777778in"}

[]{.mark}

# Figure Credits {#figure-credits .Style-Heading-1-+-Left:--0\"-First-line:--0\"}

\*Figures within this draft volume are reproduced or utilized with
permission of the author as specified below, or with permission pending
from the author. Author's refusal to grant permission for figure use or
reproduction will result in the figure being immediately removed from
this volume.

Pg 5 (top): Permission pending

Pg 5 (bottom): SCIENTIFIC AMERICAN, 08/2002. Permission pending

Pg 6 (top): <http://shiftingbaselines.org/blog/archives/2004_11.html>

Pg 6 (bottom): Permission pending

Pg 11: <http://www.noc.soton.ac.uk/JRD/SCHOOL/mt/mt001b.html>.

Pg 12:
<http://oceancolor.gsfc.nasa.gov/SeaWiFS/Gallery_Images/S19972442000244.L3m_CLI_CHLO.S19981821998212.L3m_MO_NDVI.moll.70W.jpg>

Pg 13:
<http://disc.gsfc.nasa.gov/oceancolor/scifocus/oceanColor/nab.shtml>

Pg 16 (top): Permission pending

Pg 16 (bottom): [http://www.aosltd.com/](http://www.aosltd.com/ )

pg 17: <http://www1.whoi.edu/general_info/gallery_modeling/index.html>

pg 18: Behrenfeld: Unpublished Data

pg 19 (middle): Unpublished Data

pg 19 (bottom): Number range CHAPTERM.J. Behrenfeld, E. Boss, D. A.
Siegel & D. M. Shea 2005. Carbon-based ocean productivity and
phytoplankton physiology from space. ***Global Biogeochem. Cycles***,
19, GB1006, doi:10.1029/2004GB002299

pg 22: image courtesy of James Goodman, University of Puerto Rico

pg 23 (top): Results were validated with field measurements collected by
University of South Florida and Florida International University
researchers.

pg 23 (bottom): Results were validated with field measurements collected
by University of South Florida and Florida International University
researchers.

pg 24: Permission pending

Pg 27 (top): Permission pending

Pg 27 (bottom): Permission pending

Pg 28 (top):
<http://www.aims.gov.au/pages/about/communications/backgrounders/20020130-coral-bleaching.html>

Pg 28 (bottom): (M. Kahru)
<http://spg.ucsd.edu/Satellite_Projects/MODIS_250m_data/MODIS_250m_data.htm>)

(adapted from EDOCC, 2001)

Pg 39: Permission pending

Pg 42: \"SPOT 5 10 m multispectral image of kelp cover produced by Kyle\
Cavanaugh and David Siegel (UC Santa Barbara).  SPOT data are
copyrighted by\
CNES 2005 and are distributed by Terra Image USA, LLC and SPOT IMAGE.\"

Pg 44: Images courtesy Asbury Sallenger and Amar Nayegandhi, [[USGS
Center for Coastal and Watershed
Studies]{.underline}](http://coastal.er.usgs.gov/), and Wayne Wright,
NASA Wallops Flight Facility
(<http://www.nasa.gov/audience/foreducators/9-12/features/f_lidar.html>)

Pg 45 (panel A,B): Dierssen, H.M., R.C. Zimmerman, R.A. Leathers, T.V.
Downes, and C.O. Davis, Ocean color remote sensing of seagrass and
bathymetry in the Bahamas Banks by high resolution airborne imagery,
*Limnol. Oceanogr.*, *48* (1, part 2), 444-455, 2003.

Pg 45 (panel C,D) Ryan, J., H.M. Dierssen, R.M. Kudela, C.A. Scholin,
K.S. Johnson, J. Sullivan, A.M. Fischer, E. Rienecker, P. McEnaney, and
F.P. Chavez, Coastal ocean physics and red tides: An example from
Monterey Bay, California, *Oceanography*, *18* (2), 246-255, 2005.

Pg 47: Permission Pending

Pg 49: Number range CHAPTERM.J. Behrenfeld, K. Worthington, Z. Kolber,
R.M. Sherrell, F. Chavez, P. Strutton, M. McPhaden, D. Shea. 2006.
Nutrient regulation of tropical Pacific Ocean productivity. Submitted.

Pg 54: Reproduced with permission from Dr. Watson Gregg, NASA Goddard
Space Flight Center.

# Table of Abbreviations & Acronyms 

AERONET -- Aerosol Robotic Network

ASTER - Advanced Spaceborne Thermal Emission and reflection Radiometer

AVIRIS - Airborne Visible/Infrared Imaging Spectrometer

CALIPSO - Cloud-Aerosol Lidar and Infrared Pathfinder Satellite
Observation

CDOM -- Colored dissolved organic material

CONUS -- Continental Shelf f of the United States

CZCS - Coastal Zone Color Scanner

DOC - Dissolved Organic Carbon

EAARL - Experimental Advanced Airborne Research Lidar

ENSO - El Nino-Southern Oscillation

EOS - Earth Observing System

FOV -- Field Of View

GDP -- Gross Domestic Product

GEO - Geostationary Earth Orbit

GEOSS - Group on Earth Observations System of Systems

GLAS -- Geoscience Laser Altimeter System

GMAO - Global Modeling and Assimilation Office

GOOS - Global Ocean Observing System

HNLC - High Nutrient, Low Chlorophyll

IOOS - Integrated Ocean Observing System

JAXA - Japanese Aerospace Exploration Agency

LEO - Low Earth Orbit

MEO -- Medium Earth Orbit

MLD -- Mixed Layer Depth

MAP - Modeling, Analysis and Prediction program

MODIS - Moderate Resolution Imaging Spectroradiometer

NACP - North American Carbon

NASA -- National Aeronautics and Space Administration

NASDA - National Space Development Agency of Japan

NEON - National Ecological Observatory Network

NIR -- Near Infrared

NOAA - National Oceanic and Atmospheric Administration

NOPP -- National Oceanographic Partnership Program

NPOESS - National Polar-orbiting Operational Environmental Satellite
System

NPP - NPOESS Preparatory Project

NPP - Net Primary Production

NSF - National Science Foundation

OBB -- Ocean Biology and Biogeochemistry program

OCTS - Ocean Color and Temperature Scanner

ORION -- Ocean Research Interactive Observatory Networks

PALACE - Profiling Autonomous LAgrangian Circulation Explorer

PAR -- Photosynthetically Available Radiation

PHILLS - Portable Hyperspectral Imager for Low Light Spectroscopy

PIC - Particulate Inorganic Carbon

PIC - Particulate Organic Carbon

SAR - Synthetic Aperture Radar

SeaWiFS - Sea-viewing Wide Field-of-view Sensor

SIMBIOS - Sensor Intercomparison and Merger for Biological and
Interdisciplinary Oceanic Studies

SNR -- Signal to Noise Ratio

SPOT -- Satellite Probatoire d'Observation de la Terre

SSH -- Sea Surface Height

SSS - Sea Surface Salinity

SST - Sea Surface Temperature

STEM - Science, Technology, Engineering and Mathematics

SWIR -- Short Wave Infrared Radiation

TIR -- Thermal Infrared Radiation

TOMS -- Total Ozone Mapping Sensor

TSM - Total Suspended Matter

UAV - Unmanned Aerial Vehicles

UV -- Ultraviolet

VIIRS - Visible Infrared Imager/Radiometer Suite

# Ocean Biology and Biogeochemistry Working Group

Michael Behrenfeld, Oregon State University

Paula Bontempi, NASA Headquarters

Heidi Dierssen, University of Connecticut -- Avery Point

Paul DiGiacomo, NASA Jet Propulsion Laboratory\*

Steven Lohrenz, University of Southern Mississippi

Charles McClain, NASA Goddard Space Flight Center

Frank Muller-Karger, University of South Florida

David Siegel, University of California -- Santa Barbara

Thanks to:

Paula Coble, University of South Florida

Anthony Freeman, NASA Jet Propulsion Laboratory

Norman Nelson, University of California -- Santa Barbara

Kari Risher, NASA Jet Propulsion Laboratory

James Yoder, Woods Hole Oceanographic Institution

\*Currently at NOAA-NESDIS

[^1]: Variable fluorescence is calculated as the change in fluorescence
    yield from an initial, dark adapted level (F~o~) to a light
    saturated value (F~m~), normalized to F~m~ (i.e., F~v~/F~m~ =
    (F~m~-F~o~)/F~m~). Changes in F~v~/F~m~ reflect changes in the
    efficiency of light utilization for photochemistry (i.e.,
    photosynthesis). Nocturnal decrease in F~v~/F~m~ result from
    respiratory electron transport in photosynthetic membranes and are
    exacerbated under iron limiting conditions due to insufficient
    concentrations of iron-dependent electron transport components.