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MARCH 2008

WRI POLICY NOTE

WATER QUALITY: EUTROPHICATION AND HYPOXIA No. 1

EUTROPHICATION AND

HYPOXIA IN COASTAL AREAS: 

A GLOBAL ASSESSMENT OF

THE STATE OF KNOWLEDGE

MINDY SELMAN, SUZIE GREENHALGH, ROBERT DIAZ AND ZACHARY SUGG

Within the past 50 years, eutrophication—the overenrichment of water by nutrients such as nitrogen and 

phosphorus—has emerged as one of the leading causes of water 

quality impairment. Our research identifi es over 415 areas 

worldwide that are experiencing symptoms of eutrophication, 

highlighting the global scale of the problem. 

Recent coastal surveys of the United States and Europe found 

that a staggering 78 percent of the assessed continental U.S. 

coastal area and approximately 65 percent of Europe’s Atlantic 

coast exhibit symptoms of eutrophication.1,2 In other regions, 

the lack of reliable data hinders the assessment of coastal 

eutrophication. Nevertheless, trends in agricultural practices, 

energy use, and population growth indicate that coastal eutrophication will be an ever-growing problem.

This policy note focuses on what is currently known about the 

extent of eutrophication globally, and how to improve the state 

of our knowledge to more accurately inform and drive policy 

decisions for mitigating eutrophication. Complementary policy 

notes will discuss in more detail the sources of nutrients and 

actions that can be implemented to mitigate eutrophication.

Key Messages

Eutrophication—the overenrichment of waters by nutrients—threatens and degrades many coastal ecosystems around the world. The two 

most acute symptoms of eutrophication are hypoxia (or oxygen depletion) and harmful algal blooms, which among other things can destroy 

aquatic life in affected areas. 

Of the 415 areas around the world identifi ed as experiencing some 

form of eutrophication, 169 are hypoxic and only 13 systems are classifi ed as “systems in recovery.” 

Mapping and research into the extent of eutrophication and its threats 

to human health and ecosystem services are improving, but there is 

still insuffi cient information in many regions of the world to establish 

the actual extent of eutrophication or identify the sources of nutrients. To develop effective policies to mitigate eutrophication, more 

information is required on the extent of eutrophication, the sources of 

nutrients, and the impact of eutrophication on ecosystems.

Recommendations

To improve knowledge of where eutrophication is occurring and its 

impacts, environmental agencies or coastal authorities worldwide 

need to proactively assess and monitor water quality, specifi cally those 

variables commonly linked to eutrophication such as nutrient levels 

and dissolved oxygen. In addition, internationally accepted methods 

and defi nitions for assessing and classifying eutrophic coastal waters—including proxies for eutrophication—need to be developed.

In Asia, Africa, and Latin America, environmental agencies or coastal 

authorities should:

1. Undertake systematic and routine assessments of coastal areas, 

particularly those exhibiting symptoms of eutrophication.

2. Develop transparent and public reporting procedures for tracking 

the occurrence of eutrophication and hypoxia, as well as monitoring 

their impact on ecosystem health.

3. Develop and adopt decision-support tools—such as nutrient budgets and water quality models—that can facilitate the development 

of appropriate local and regional responses to eutrophication.

In the United States, Europe, and Australia, environmental agencies 

or coastal authorities should:

1. Continue coastal zone assessments.

2. Ensure that eutrophication assessment methodologies are being 

consistently applied.

3. Enhance existing decision-support tools and develop tools for those 

areas where none currently exist.

Red algal bloom at Leigh, near Cape Rodney, NZ.

PHOTO BY MIRIAM GODFREY. USED BY PERMISSION OF NIWA SCIENCE. 
POLICY NOTE: Eutrophication and Hypoxia in Coastal Areas

March 2008 2 WORLD RESOURCES INSTITUTE

WHY IS EUTROPHICATION A PROBLEM?

The rise in eutrophic and hypoxic events has been primarily attributed to the rapid increase in intensive agricultural 

practices, industrial activities, and population growth, which 

together have increased nitrogen and phosphorus fl ows in 

the environment. Human activities have resulted in the near 

doubling of nitrogen and tripling of phosphorus fl ows to the environment when compared to natural values.3 By comparison, 

human activities have increased atmospheric concentrations 

of carbon dioxide, the gas primarily responsible for global 

warming, by approximately 32 percent since the onset of the 

industrial age.4

Before nutrients—nitrogen in particular—are delivered to 

coastal ecosystems, they pass through a variety of terrestrial and 

freshwater ecosystems, causing other environmental problems 

such as freshwater quality impairments, acid rain, the formation of greenhouse gases, shifts in community food webs, and 

a loss of biodiversity.5

Once nutrients reach coastal systems, they can trigger a number 

of responses within the ecosystem. The initial impacts of nutrient increases are the excessive growth of phytoplankton, microalgae (e.g., epiphytes and microphytes), and macroalgae (i.e., 

seaweed). These, in turn, can lead to other impacts such as:

• Loss of subaquatic vegetation as excessive phytoplankton, 

microalgae, and macroalgae growth reduce light penetration.

• Change in species composition and biomass of the benthic (bottom-dwelling) aquatic community, eventually 

leading to reduced species diversity and the dominance 

of gelatinous organisms such as jellyfi sh. 

• Coral reef damage as increased nutrient levels favor 

algae growth over coral larvae. Coral growth is inhibited 

because the algae outcompetes coral larvae for available 

surfaces to grow. 

• A shift in phytoplankton species composition, creating 

favorable conditions for the development of nuisance, 

toxic, or otherwise harmful algal blooms. 

• Low dissolved oxygen and formation of hypoxic or “dead” 

zones (oxygen-depleted waters), which in turn can lead to 

ecosystem collapse. 6

The scientifi c community is increasing its knowledge of how 

eutrophication affects coastal ecosystems, yet the long-term 

implications of increased nutrient fl uxes in our coastal waters 

are currently not entirely known or understood. We do know 

that eutrophication diminishes the ability of coastal ecosystems 

to provide valuable ecosystem services such as tourism, recreation, the provision of fi sh and shellfi sh for local communities, 

sportfi shing, and commercial fi sheries. In addition, eutrophication can lead to reductions in local and regional biodiversity. 

Today nearly half of the world’s population lives within 60 kilometers of the coast, with many communities relying directly 

on coastal ecosystems for their livelihoods.7 This means that a 

signifi cant portion of the world’s population is vulnerable to the 

effects of eutrophication in their local coastal ecosystems.

Harmful Algal Blooms and Hypoxia. Two of the most acute and 

commonly recognized symptoms of eutrophication are harmful 

algal blooms and hypoxia. 

Harmful algal blooms can cause fish kills, human illness 

through shellfi sh poisoning, and death of marine mammals 

and shore birds.8 Harmful algal blooms are often referred to 

as “red tides” or “brown tides” because of the appearance of 

the water when these blooms occur. One red tide event, which 

occurred near Hong Kong in 1998, wiped out 90 percent of 

the entire stock of Hong Kong’s fi sh farms and resulted in an 

estimated economic loss of $40 million USD.9,10

Hypoxia, considered to be the most severe symptom of eutrophication, has escalated dramatically over the past 50 years, 

increasing from about 10 documented cases in 1960 to at least 

169 in 2007.11,12 Hypoxia occurs when algae and other organisms die, sink to the bottom, and are decomposed by bacteria, 

using the available dissolved oxygen. Salinity and temperature 

differences between surface and subsurface waters lead to 

stratifi cation, limiting oxygen replenishment from surface 

waters and creating conditions that can lead to the formation 

of a hypoxic or “dead” zone.13

Two of the most well-known hypoxic areas are the Gulf of 

Mexico and the Black Sea. The Gulf of Mexico has a seasonal 

hypoxic zone that forms every year in late summer. Its size 

varies; in 2000, it was less than 5,000 km2, while in 2002 it 

was approximately 22,000 km2 (or the size of the U.S. state of 

Massachusetts). While the economic consequences of the Gulf 

of Mexico dead zone are still unclear, concern over its increasing size led to the formation of the Mississippi River/Gulf of 

Mexico Watershed Nutrient Task Force in 1997 to develop a 

strategy to reduce the fi ve-year running average areal extent of 

the Gulf of Mexico hypoxic zone to less than 5,000 km2. 

The Black Sea, which was once the largest dead zone in the 

world, had 26 commercially viable fi sh species in the 1960s but 
POLICY NOTE: Eutrophication and Hypoxia in Coastal Areas

March 2008 3 WORLD RESOURCES INSTITUTE

only fi ve species by the 1980s.14 The growth of the Black Sea 

hypoxic zone was attributed to the intensifi cation of agriculture 

in the former Soviet Union. It has been “in recovery” since 

the economic collapse of Eastern Europe in the 1990s, which 

resulted in signifi cant reductions in fertilizer use.

WHAT ARE THE SOURCES OF NUTRIENTS?

Agriculture, human sewage, urban runoff, industrial effl uent, 

and fossil fuel combustion are the most common sources of 

nutrients delivered to coastal systems. Among regions, there 

are signifi cant variations in the relative importance of each 

nutrient source. For example, in the United States and the 

European Union, agricultural sources (particularly animal 

manure and commercial fertilizers) are generally the primary 

contributors to eutrophication, while sewage and industrial 

discharges, which usually receive some treatment prior to 

discharge, are a secondary source. However, in Latin America, 

Asia, and Africa, wastewater from sewage and industry are 

often untreated and may often be the primary contributors to 

eutrophication. It is currently estimated that only 35 percent 

of wastewater in Asia is treated, 14 percent in Latin America 

and the Caribbean, and less than 1 percent in Africa.15

Atmospheric sources of nitrogen are also recognized as a signifi cant contributor of nutrients in coastal areas.16 Nitrogen 

from fossil fuel combustion and volatilization from fertilizers 

and manure is released into the atmosphere and redeposited on 

land and in water by wind, snow, and rain. In the Chesapeake 

Bay in the mid-Atlantic region of the eastern United States, 

atmospheric sources of nitrogen account for a third of all controllable nitrogen that enters the Bay; similarly, in the Baltic 

Sea in Europe, atmospheric nitrogen accounts for a fourth of 

all controllable nitrogen.

WHERE ARE THE GLOBAL EUTROPHIC AND HYPOXIC

AREAS?

Our research identifi ed 415 eutrophic and hypoxic coastal 

systems worldwide (Figure 1).17 Of these, 169 are documented 

hypoxic areas, 233 are areas of concern, and 13 are systems 

in recovery.

The coastal areas reported as experiencing eutrophication are 

steadily growing. This is because of the increasing prevalence 

of eutrophication and advances in identifying and reporting 

eutrophic conditions.
POLICY NOTE: Eutrophication and Hypoxia in Coastal Areas

March 2008 4 WORLD RESOURCES INSTITUTE

The fi rst comprehensive list of hypoxic zones was compiled by 

Diaz and Rosenberg in 1995 and identifi ed 44 documented 

hypoxic areas.18 Twelve years later, there are 169 documented 

hypoxic areas, a nearly four-fold increase. The list of hypoxic 

areas assembled by Diaz was compiled from scientifi c literature and identifi ed the majority of documented hypoxic areas. 

However, the list did not include areas with suspected—but 

not documented—hypoxic events or systems that suffer from 

other impacts of eutrophication such as nuisance or harmful 

algal blooms, loss of subaquatic vegetation, and changes in 

the structure of the benthic aquatic community (for example, 

decline in biomass, changes in species composition, and loss 

of diversity). 

To supplement this list of hypoxic zones, the authors undertook 

an extensive literature review to catalog systems experiencing 

any symptoms of eutrophication, including—but not limited 

to—hypoxia.19 The eutrophic areas identifi ed were categorized 

as:

• Documented hypoxic areas. Areas with scientifi c evidence 

that hypoxia was caused, at least in part, by nutrient 

overenrichment. This category includes the most recent 

list of hypoxic areas compiled by Diaz (excluding hypoxia 

caused by natural upwelling of nutrients), as well as some 

additional systems identifi ed by our research.20

• Areas of concern. Systems that exhibit effects of eutrophication, such as elevated nutrient levels, elevated chlorophyll a levels, harmful algal blooms, changes in the benthic 

community, damage to coral reefs, and fi sh kills. These 

systems are impaired by nutrients and are possibly at risk 

of developing hypoxia. Some of the systems classifi ed as 

areas of concern may already be experiencing hypoxia, but 

lack conclusive scientifi c evidence of the condition.

• Systems in recovery. Areas that once exhibited low dissolved oxygen levels and hypoxia, but are now improving. 

For example, the Black Sea once experienced annual 

hypoxic events, but is now in a state of recovery. Others, 

like Boston Harbor in the United States and the Mersey 

Estuary in the United Kingdom, also have improved 

water quality resulting from better industrial and wastewater controls.

WHERE ARE THE DATA INCONSISTENCIES AND GAPS?

The actual extent and prevalence of eutrophication in many 

regions is only beginning to be studied. As a consequence, data 

do not exist or are not publicly available for many areas that 

may be suffering from the effects of eutrophication. In addition, the data that do exist are often inconsistent in terms of 

parameters measured, indicators used, and the scale at which 

data are reported. 

Given the state of global data, the number of eutrophic and 

hypoxic areas around the world is expected to be greater than 

the 415 listed here. The most underrepresented region is Asia. 

Asia has relatively few documented eutrophic and hypoxic 

areas despite large increases in intensive farming methods, 

industrial development, and population growth over the past 

20 years. Africa, Latin America, and the Caribbean also have 

few reliable sources of coastal water quality data, making it 

diffi cult to assess the true level of eutrophication. 

The scale at which data for eutrophic areas are reported varies greatly. For example, red tides and other eutrophic events 

are frequently recorded in the South China Sea, Yellow Sea, 

and Bohai Sea. However, the actual extent of eutrophication 

or hypoxia in specifi c bays and estuaries within these systems 

is unknown. Therefore, these areas are coarsely recorded in 

Figure 1 and most likely represent several affected bays and 

estuaries along the Chinese coast. Conversely, within the 

well-studied Chesapeake Bay system, there are 12 distinct and 

documented eutrophic and hypoxic zones. 

The United States, European Union, and Australia—all of which 

have each undertaken comprehensive coastal surveys in the past 

fi ve years—have the most comprehensive coastal data on eutrophication. However, even within the United States and Europe, 

the quality, consistency, and availability of water quality data 

varies. For example, in Europe, the coastal survey coordinated 

through the Commission for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) highlighted the 

variability in quality and availability of monitoring data among 

the various European countries.21 Several coastal areas lacked 

dissolved oxygen measures and many of the secondary effects 

of eutrophication, such as fi sh kills and changes in the benthic 

community, were not extensively monitored. The U.S. National 

Oceanic and Atmospheric Agency’s (NOAA) National Estuarine 

Eutrophication Assessment program, which conducted national 

eutrophication surveys in 1999 and 2007, experienced data 

issues similar to those encountered in the OSPAR survey. Of 

the 141 U.S. estuaries evaluated in 2007, 30 percent lacked 

adequate data for assessing their eutrophication status.

Most systems identifi ed as hypoxic or eutrophic also lack 

detailed data on the sources of nutrient impairments and the 

relative contribution of each source. Some systems that have 

developed detailed nutrient budgets include the Chesapeake 
POLICY NOTE: Eutrophication and Hypoxia in Coastal Areas

March 2008 5 WORLD RESOURCES INSTITUTE

Bay, Baltic Sea, Black Sea, Gulf of Mexico (Mississippi-Atchafalaya plume), and Tampa Bay. The absence of detailed nutrient budgets for the majority of eutrophic and hypoxic systems 

around the world highlights the lack of concerted research 

efforts in these areas, compromising the ability to effectively 

address and manage nutrient overenrichment.

HOW DO WE IMPROVE THE STATE OF KNOWLEDGE?

To better assess the global, regional, and local extent of eutrophication, we need more and better data. Improving our knowledge 

of where eutrophication is occurring, the sources contributing 

to the problem, and the effects of eutrophication on marine 

ecosystems and human communities ultimately infl uences the 

ability of policy-makers to decide where and how resources can 

be used most effectively to address eutrophication.

Closing the knowledge gap requires increased and improved 

water quality monitoring and assessment of estuarine and 

coastal waters. Without this information, communities cannot 

effectively manage coastal ecosystems and address land-based 

sources of pollution. Specifically, time series monitoring 

data—on nutrient levels, chlorophyll a (as an indicator of the 

presence of phytoplankton), and dissolved oxygen—as well 

as eutrophication response parameters—such as loss of subaquatic vegetation, fi sh kills, and algal blooms—are needed to 

evaluate the extent and degree of eutrophication. Moreover, 

widespread use and adoption of methods to classify and defi ne 

eutrophic waters (such as the ones developed by NOAA and 

OSPAR) are needed to increase the transparency, consistency, 

and comparability of water quality information. For example, 

currently no common defi nition of “hypoxia” exists and the 

interpretation of what is hypoxic can vary widely from place 

to place. 

In countries or regions where robust and systematic monitoring programs are unlikely to be implemented due to limited 

resources, it would be benefi cial to develop credible and consistent proxies for water quality (such as turbidity or sulfi de 

smell) that could be used to identify likely eutrophic areas. 

Finally, decision support tools that enable researchers and 

policy-makers to formulate appropriate responses to eutrophication need to be continually developed and more widely 

adopted by local and regional entities. Such tools include:

• Watershed models to assess nutrient delivery and ecosystem impacts;

• Nutrient balance assessments to determine the sources of 

nutrients and relative contribution of each source;

• Regional and international online information portals 

for compiling and sharing water quality information and 

research;

• Nutrient loss estimation tools; and

• Tools to help assess the effectiveness of alternative scenarios for reducing nutrient inputs. 

Implementation of these tools is especially needed to estimate 

coastal impacts and target appropriate policy responses in countries and regions where actual monitoring data are scarce.

Eutrophication is an issue that requires greater attention by governments and society in general. Left untouched, it may have 

dire consequences for many ecosystems, the food webs that they 

support, and the livelihoods of the populations that depend on 

them. To get a better grasp on the immediate and long-term 

consequences of eutrophication, we need more resources and 

better information. Improving our knowledge and information 

on eutrophication is the fi rst step in developing robust policy 

measures to begin reversing or halting its impacts.

ABOUT THE AUTHORS

Mindy Selman is a senior associate in the People and 

Ecosystems Program of the World Resources Institute. 

Ph: +1-202-729 7644. Email: mselman@wri.org

Suzie Greenhalgh is a senior economist at Landcare 

Research New Zealand Ltd. Ph: +64-9-574 4132. 

Email: greenhalghs@landcareresearch.co.nz

Robert Diaz is a professor of marine science at the College 

of William and Mary, Virginia Institute of Marine Science. 

Ph: +1-804-684 7364. Email: diaz@vims.edu

Zachary Sugg is a research analyst with the People and 

Ecosystems Program of the World Resources Institute. 

Ph: +1-202-729 7605. Email: zsugg@wri.org

ACKNOWLEDGMENTS

The authors are grateful for the contributions provided by 

Donald Anderson, James Galloway, Paul Harrison, Laurence 

Mee, Qian Yi, and Nancy Rabalais, who served on a WRI 

eutrophication advisory panel. The authors would also like to 

acknowledge Kersey Sturdivant for his research assistance in 

identifying areas of eutrophication. In addition, the authors 

thank Craig Hanson, Lauretta Burke, Amy Cassara, Dan 

Tunstall, Laurence Mee, and James Galloway for reviewing 

earlier drafts of this paper. Finally, we extend our thanks to 

the Linden Trust for Conservation and the David and Lucile 

Packard Foundation for their support of this research.
POLICY NOTE: Eutrophication and Hypoxia in Coastal Areas

March 2008 6 WORLD RESOURCES INSTITUTE

NOTES

 1. See Bricker, S. B., Longstaff, W. Dennison, A. Jones, K. Boicourt, C. 

Wicks, and J. Woerner. 2007. Effects of Nutrient Enrichment in the 

Nation’s Estuaries: A Decade of Change. NOAA Coastal Ocean Program 

Decision Analysis Series No. 26. Silver Spring, MD: National Centers 

for Coastal Ocean Science. Online at: http://ccma.nos.noaa.gov/publications/eutroupdate/

 2. See OSPAR Commission. 2003. OSPAR integrated report 2003 on the 

eutrophication status. London, U.K.: OSPAR. 

 3. See Howarth, R. and K. Ramakrrshna. 2005. “Nutrient Management.” 

In K. Chopra, R. Leemans, P. Kumar, and H. Simons, eds. Ecosystems 

and Human Wellbeing: Policy Responses. Volume 3 of the Millennium 

Ecosystem Assessment (MA). Washington, DC: Island Press. 

 4. See National Oceanic and Atmospheric Administration (NOAA). “Global 

Warming: Frequently asked questions.” Available at: http://lwf.ncdc.

noaa.gov/oa/climate/globalwarming.html. (accessed January 15, 2008)

 5. See Galloway, J.N, J.D. Aber,, J.W. Erisman, S.P. Seitzinger, R.W. 

Howarth, E.B. Cowling, and B.J. Cosby. 2003. “The Nitrogen Cascade.” 

Bioscience 53( 4): 341–356

 6. For a discussion on the impacts of eutrophication on coastal ecosystems, 

see Mee, L. 2006. “Reviving Dead Zones.” Scientifi c American 295 (5): 

79–85.

 7. See: UN Chronicle Online Edition. “Risks, Untreated Sewage Threatens Seas, Coastal Population.” http://www.un.org/Pubs/chronicle/2003/

issue1/0103p39.html. (accessed January 15, 2008)

 8. Harmful algal blooms refer to several species of algae that produce toxins that are harmful to aquatic life. See Anderson, D. M., P. M. Gilbert, 

and J. M. Burkholder. 2002. “Harmful Algal Blooms and Eutrophication: Nutrient Sources, Composition, and Consequences.” Estuaries 25 

(4b): 704–726.

 9. See: Terra Daily Online Edition. “Hong Kong red tide spreads,” (June 

10, 2007). http://www.terradaily.com/reports/Hong_Kong_Red_Tide_

Spreads_999.html (accessed February 8, 2008).

 10. See Lu, S., and I. J. Hodgkiss. 2004. “Harmful algal bloom causative 

collected from Hong Kong waters.” Hydrobiologia.512(1-3): 231-238

 11. Hypoxia is generally defi ned as having a dissolved oxygen concentration 

of 2.0 milligrams per liter or less.

 12. See Diaz, R. J., J. Nestlerode, and M. L. Diaz. 2004. “A global perspective on the effects of eutrophication and hypoxia on aquatic biota.” In 

G. L. Rupp and M. D. White, eds. Proceedings of the 7th International 

Symposium on Fish Physiology, Toxicology, and Water Quality, Tallinn, 

Estonia, May 12-15, 2003. Athens, Georgia: U.S. Environmental Protection Agency, Ecosystems Research Division (EPA 600/R-04/049).

 13. See Rabalais, N. N., and R. E. Turner. 2001. Coastal hypoxia consequences for living resources and ecosystems. Washington, DC: American 

Geophysical Union.

 14. See Europe Now|Next. “Is the Black Sea recovering?” http://www.europe.culturebase.net/contribution.php?media=307 (accessed December 

30, 2008)

15. See Howarth, R. and K. Ramakrrshna. 2005. “Nutrient Management.” 

In K. Chopra, R. Leemans, P. Kumar, and H. Simons, eds. Ecosystems 

and Human Wellbeing: Policy Responses. Volume 3 of the Millennium 

Ecosystem Assessment (MA). Washington, DC: Island Press. 

 16. See Spokes, L. J., and T. D. Jickells. 2005. “Is the atmosphere really an 

important source of reactive nitrogen to coastal waters?” Continental 

Shelf Research 25: 2022–2035.

 17. Region-specifi c maps as well as the data used to create these maps is 

made available on WRI’s website, www.wri.org/project/water-quality.

 18. See Diaz, R. and R. Rosenburg. 1995. “Marine benthic hypoxia: a 

review of its ecological effects and the behavioural responses of benthic 

macrofauna.” Oceanography and Marine Biology: an Annual Review 33: 

245–303.

 19. The primary data sources include:

• Diaz, R. J., J. Nestlerode, and M. L. Diaz. 2004. “A global perspective 

on the effects of eutrophication and hypoxia on aquatic biota.” In G. L. 

Rupp and M. D. White, eds. Proceedings of the 7th International Symposium on Fish Physiology, Toxicology, and Water Quality, Tallinn, Estonia, 

May 12-15, 2003. Athens, Georgia: U.S. Environmental Protection 

Agency, Ecosystems Research Division (EPA 600/R-04/049). 

• Bricker, S. B., Longstaff, W. Dennison, A. Jones, K. Boicourt, C. Wicks, 

and J. Woerner. 2007. Effects of Nutrient Enrichment in the Nation’s 

Estuaries: A Decade of Change. NOAA Coastal Ocean Program Decision 

Analysis Series No. 26. Silver Spring, MD: National Centers for Coastal 

Ocean Science. Online at: http://ccma.nos.noaa.gov/publications/eutroupdate/.

• OSPAR Commission. 2003. OSPAR integrated report 2003 on the eutrophication status. London, UK: OSPAR. 

• OzEstuaries. 2005. “Anoxic and Hypoxic Events.” Online at: http://www.

ozestuaries. org/indicators/anoxic_hypoxic_events.jsp (August, 2005).

• United Nations Environment Program (UNEP). 2006. Challenges to 

International Waters – Regional Assessments in a Global Perspective. 

Nairobi, Kenya: United Nations.

 20. See Diaz, R. J., J. Nestlerode, and M. L. Diaz. 2004. “A global perspective on the effects of eutrophication and hypoxia on aquatic biota.” In 

G. L. Rupp and M. D. White, eds. Proceedings of the 7th International 

Symposium on Fish Physiology, Toxicology, and Water Quality, Tallinn, 

Estonia, May 12-15, 2003. Athens, Georgia: U.S. Environmental Protection Agency, Ecosystems Research Division (EPA 600/R-04/049).

 21. OSPAR called for the uniform assessment of coastal waters by signatory 

countries. Signatory countries to the 1992 Oslo-Paris Convention for 

the Protection of the Marine Environment of the North-East Atlantic 

(OSPAR Convention) include Belgium, Denmark, France, Germany, 

Ireland, The Netherlands, Norway, Portugal, Spain, Sweden, and the 

United Kingdom. 

ABOUT WRI

The World Resources Institute is an environmental think tank that goes beyond research 

to fi nd practical ways to protect the Earth and 

improve people’s lives. Our mission is to move 

human society to live in ways that protect the 

Earth’s environment and its capacity to provide for the needs and aspirations of current 

and future generations.

Forthcoming publications in this series include:

• Eutrophication: Sources and Drivers of Nutrient Pollution

• Eutrophication: A Policy Framework for Addressing 

Nutrient Pollution

Please visit www.wri.org/publications for links to available 

publications.