STAR

REPORT

Vol. 1 Issue 2 Dec. 1997 A product of the National Center for Environmental Research and Quality Assurance

Most microscopic algae are not harmful, but a few species produce potent toxins

that can be transferred through the food chain, affecting and sometimes killing

zooplankton, shellfish, fish, birds, marine mammals and even humans.

HARMFUL ALGAL BLOOMS

U.S. EPA Office of Research

and Development’s Science

To Achieve Results (STAR)

Research in Progress

Harmful algal blooms occur when some

species of algae, the universally present, microscopic plants that form the base of aquatic

food chains, multiply quickly and aggregate in

a given coastal area. Most microscopic algae

are not harmful, but a few species produce

potent toxins that can be transferred through

the food chain, affecting and sometimes killing zooplankton, shellfish, fish, birds, marine

mammals and even humans. Sometimes the

algae become so abundant that they form

dense, visible patches

near the water’s surface.

"Red tide" or “brown

tide” are common

names for such phenomena, because some

algae contain pigments

that make the water appear colored. However,

these terms are misnomers because the blooms

are not associated with tides, and some algae

never reach densities that discolor the water

but nevertheless have devastating effects on fish

and other living things. Scientists now prefer

the term “harmful algal blooms” (HAB) to encompass all blooms with negative impacts.

HABs that do not involve visible discoloration of the water include outbreaks of the dinoflagellate Pfiesteria and related species. This

microorganism’s attacks on fish tissues create

open sores, and can ultimately lead to massive

fish kills. Pfiesteria and related species release toxins

believed to cause human

sores and nervous system

damage due to exposure to

affected waters. The term

HAB also includes blooms of

another type of algae, the

large seaweeds and other

soft-tissued aquatic plants

called “macroalgae”, which

are stimulated by excess nutrients or other ecological

imbalances. Macroalgae

do not create toxic hazards.

But they create noxious conditions and ecosystem imbalances if stimulation by nutrients

leads to excess growth, decay and oxygen

depletion, overgrowth of habitats, or local extinctions of other plants and animals.

Electron micrograph of Pfiesteria (cyst form)
2

General Information: The Environmental Protection Agency’s STAR Research Program

Grants described in this report are part of EPA’s Science to Achieve Results (STAR) program, a major research

initiative designed to improve the quality of scientific information available to support environmental decision

making. The STAR program is managed by EPA’s National Center for Environmental Research and Quality Assurance in the Office of Research and Development (ORD). The program funds approximately 200 new grants every

year, with the typical grant lasting three years. Funding levels vary from $50,000 to over $500,000 per year, with

FY 1997 funding level at about $80 million for grants to individual principal investigators or groups of investigators.

Additional STAR funds are provided for a number of Research Centers specializing in scientific areas of particular

concern to EPA, and for a fellowship program supporting graduate students conducting environmental research.

HAB Impacts on

Public Health and

Ecosystems

Common impacts of

HABs are fish kills, mass mortalities of wild and farmed

fish and shellfish in bays, estuaries or marine coastal

waters. Human illness and

even deaths can result from

eating seafood contaminated by some of the alge

that create blooms, and

deaths of marine mammals,

seabirds and other animals

high in aquatic food chains

are common in some regions. In addition, the

blooms cause alterations of

marine habitats and food

webs, so that plants and animals normally present become rare, and unusual,

sometimes less valuable or

noxious species can replace

them.

A Coordinated Response:

The ECOHAB National Research Plan

Over the last several decades, the frequency of HABs in the

United States has markedly increased. The causes of this expansion

are still a matter of debate, with possible explanations ranging from

natural changes in species dispersals to a host of human-related

phenomena such as nutrient enrichment, climatic shifts or transport of algal species via ship ballast water. Whatever the reasons,

virtually all coastal regions of the U.S. are now subject to an unprecedented variety and frequency of HAB events. The U.S. is not alone

in this respect, as nations throughout the world are faced with increasing incidences of HABs caused by an array of harmful species.

HABs result from physical, chemical, and biological mechanisms and interactions that are for the most part poorly understood.

Focused research into these mechanisms is urgently needed. In the

United States, a coordinated research program called ECOHAB (Ecology and Oceanography of Harmful Algal Blooms) has been developed to meet these research needs. A group of federal agencies,

led by the National Oceanic and Atmospheric Administration

(NOAA), has developed a national ECOHAB research agenda to guide

• ENV RI ONMENTAL PROTECTION AGE N CY

U

•

NITED STATES

NAT OI NAL OCEANIC AND ATMOSPHERIC ADMINISTRAT OI N

U.S. DEPARTMENT OF COMMERCE
3

academic and government research. The objective of the

ECOHAB research program is to

investigate fundamental physical, biological and chemical

oceanographic questions critical

to management of fisheries resources and public and ecosystem health in areas threatened

by toxic and harmful algae. The

Environmental Protection

Agency (EPA) is a partner in the

ECOHAB research effort. This

report highlights ECOHAB research funded through EPA’s

extramural research program,

the Science to Achieve Results

(STAR) program. Additional information about ECOHAB research is available from the

ECOHAB Internet website referenced in the section, “Find Out

More”.

RESEARCH SUPPORTED

BY EPA AND OTHER

AGENCIES

Pfiesteria Research

In 1997, an EPA STAR research grant was awarded to

North Carolina State University

to fill critical

gaps in our understanding of

the causes of

blooms of the

toxic dinoflagellate, Pfiesteria

piscicida, as well

as to improve

upon available

techniques for detecting this organism in the natural environment. This is the species believed

responsible for recent fish kills in

coastal waters of North Carolina

and the eastern shore of the

Chesapeake Bay, in which some

researchers, fish and wildlife

agency employees and fishermen

experienced skin lesions and nervous system damage, such as

memory loss, that may have been

due to contact with the contaminated water.

Specific objectives of the

North Carolina study include the

following: 1) to examine the effects on Pfiesteria of different types

of nutrients, including nitrogen

and phosphorus-containing compounds from natural and human

sources; 2) to develop speciesspecific fluorescent-labeled molecular probes to allow rapid, routine detection of Pfiesteria’s major life stages at sites where fish

lesions or fish kills occur; and 3)

to assess lethal and sublethal effects of Pfiesteria on commercially

and ecologically valuable shellfish

species. These results will support

more rapid and accurate field testing to determine when a Pfiesteria

problem exists in an area. And

results of the nutrient

testing may provide insights to improve strategies for preventing or reducing Pfiesteria blooms

through pollution prevention approaches for

nutrient sources in

coastal watersheds.

Other Toxic

Dinoflagellates

Toxic chemicals released

by the common dinoflagellate

algae Gymnodinium breve can

kill planktonic animals that feed

on them, or can be retained in

the plankton and passed along

to fish and other organisms

higher in the food chain. An EPA

STAR grant has been awarded

to the Florida State Department of Environmental Protection for research into

G. breve’s toxicity and growth

and reproductive impacts on a

key planktonic animal, the copepod Acartia tonsa. This study

will also refine a method for detecting G. breve toxins in water, air and sediments. Results

will help establish how long G.

breve toxins remain active in the

environment, and help scientists

The causes of HABs

expansion are still a

matter of debate,

with possible explanations ranging

from natural

changes in species

dispersal and aggregation to a host of

human-related phenomena such as

nutrient enrichment,

climatic shifts and

transport of algae in

ship ballast water.
4

To predict conditions under

which toxic

blooms may

occur, scientists

need to understand how the

algae interact

with all parts of

the food web.

better predict effects of G. breve

blooms on animal abundances

and the contamination of critical

food chain organisms such as

Acartia.

To predict conditions under

which toxic dinoflagellate blooms

may occur, scientists need to understand how the algae interact

with all parts of the food web.

Blooms may result from reduced

consumption of the algae by animals that normally eat

them, planktonic animals and filter-feeding shellfish such as

oysters, mussels and

clams. For example,

perhaps initially modest changes in abundance of toxic algae

could lead to some

consumer animals being killed by the toxins, setting up a cycle

in which increasingly

fewer consumers and

more harmful algae

survive, with a toxic bloom the

result. A joint study by the National Marine Fisheries Service

(NMFS) laboratory in Milford,

Connecticut, the Bigelow Laboratory for Ocean Sciences in

Maine, the University of Connecticut and the University of

Pennsylvania is taking advantage

of the NMFS lab’s dinoflagellate

cultures to assess grazing and toxicity rates of animals exposed to

toxic algae. This will help scientists predict ecological conditions,

such as balances of species

present, that can predispose

coastal ecosystems to HAB incidents.

Four dinoflagellate ECOHAB

studies are being funded by other

agencies. NOAA is supporting a

study of the ecology in the Gulf

of Maine of the toxic dinoflagellate Alexandrium, comprehensively assessing chemical, physical oceanographic and biological

factors affecting bloom development. The National Science

Foundation (NSF) is

supporting a University of Rhode Island

study of the control

of Alexandrium

blooms and food

chain transfers of toxins due to zooplankton grazing. Another

NSF study, by the

Medical University

of South Carolina, is

investigating how

bacteria that can kill

algae may affect

Gymnodinium blooms

in the Gulf of Mexico. This alga

frequently causes fish kills, and

can result in neurotoxic shellfish

poisoning in humans.

Another NSF-supported

project involves research by the

California State University at

Monterey Bay into effects of paralytic shellfish poisoning (PSP) on

higher level marine predators.

PSP, caused by Gonyaulax

catenella, can cause serious illness

or death in humans consuming

mussels or other contaminated

shellfish. Researchers will investigate whether certain birds and

sea otters can detect and avoid

PSP contaminated shellfish, the

extent to which they are harmed

if they consume contaminated

shellfish, and whether there are

significant effects on bird and otter populations due to PSP.

Toxic Diatoms

While HABs in the United

States usually involve microscopic

algae called dinoflagellates, sometimes diatoms, the other most

common microalgae, are at fault.

Most diatom species are not toxic,

but some are. On the west coast,

diatoms in the Pseudo-nitzschia

group have caused human poisonings from eating clams and

crabs in Oregon and Washington.

They have also caused wildlife

deaths, such as seabird kills in

California. The University of

California at Santa Cruz has received a STAR grant to investigate

causes of toxic diatom blooms.

Hypotheses they are testing include the following: 1) changing

concentrations of the major diatom nutrients, nitrogen and silicate, may trigger a bloom if the

nutrient that limits growth in an

area becomes increasingly available; 2) increasing concentrations

of iron, a “micronutrient” needed

in trace amounts, might stimulate

the blooms; or 3) not only are

the diatoms’ growth and reproduction affected by iron, nitrogen

and/or silicate concentrations, but

the amount of toxins produced

and released by each diatom may

be enhanced by specific nutrient

or micronutrient conditions. ReTo predict conditions under

which toxic

blooms may

occur, scientists

need to understand how the

algae interact

with all parts of

the food web.

EPA STAR RESEARCH: Building a Foundation for Sound Environmental Science
5

Find Out More About the STAR Research Program

search results are expected to

make a significant contribution to

management strategies for predicting, monitoring and implementing public health responses

to toxic diatom blooms in the

Pacific and elsewhere.

Other Toxic Algae

Tiny bacteria-like plants

called cyanobacteria, with the

common name “blue-green algae”, are a frequent cause of HABs

in stressed tropical waters. They

release a toxin that can be deadly

to coral reef animals, or to humans that eat fish or invertebrates

from an affected area. The

growth of blue-green algae, like

all algae, may be stimulated by

the nutrients and micronutrients,

principally nitrogen, phosphorus

and iron. However, an additional

mechanism may be involved in

blue-green algae blooms, similar

to that discussed in relation to

toxic dinoflagellates. This is that,

once they are stimulated to increase in abundance, the toxins

they emit, called “secondary metabolites”, may kill or keep away

fish and other animals that graze

on algae, resulting in a sudden

HAB as the toxic algae are released from grazing pressure. The

University of Guam has received

an EPA STAR grant to study each

of these possible causes of bluegreen algae blooms. They will

document bloom patterns in

space and time, and assess the

roles played by various sources of

coastal nutrient pollution as compared to impacts of overfishing of

grazing species, and the impacts

Further information on the STAR program is available from the following sources:

Internet Website, managed by the ORD National Center for Environmental Research and Quality Assurance (NCERQA):

URL: http://www.epa.gov/ncerqa

Mailing Address:

Office of Research and Development

National Center for Environmental Research and Quality Assurance

Office of the Director (8701 R)

401 M Street, SW

Washington, DC 20460

Or, use the Telephone Hotline, 1-800-490-9194, to leave messages and

receive auto faxes of announcements.

Other HAB research information is available at the ECOHAB Website:

<http://habserver1.whoi.edu/hab>

of secondary metabolites in reducing grazing.

During the past decade, the

brown tide organism Aureococcus

anophagefferens has devastated

the ecology of several bays on

New York’s Long Island, destroying commercial shellfisheries. Another, related organism causes

persistent brown tides in some

Texas bays. These microalgae are

very recently discovered, and are

considered an entirely new major grouping (an order) of plants.

Many of their basic characteristics

have yet to be determined. NSF

is supporting research by the New

York University Medical Center

into the population genetics of

these algae, which may help in

developing strategies for reducing or controlling the blooms.
 STAR Research Projects Described in this Report and other Partner Awards

5) “Algicidal bacteria and the

regulation of Gymnodinium

breve blooms in the Gulf of

Mexico.”; lead PI institution:

Medical University of South

Carolina

6) “Ecophysiology studies of

Pseudo-nitzschia species.”; lead

PI institution: University of California, Santa Cruz

1) “ECOHAB-Gulf of Maine:

The ecology and oceanography

of toxic Alexandrium blooms in

the Gulf of Maine.”; lead PI institution: Woods Hole

Oceanographic Institution, RI

2) “ECOHAB: Florida.”; lead PI

institution: Flordia Dept. of Environmental Protection

3) “Trophic effects of two dinoflagellates.” lead PI institution: University of Connecticut (also NMFS Laboratory,

Milford, CT)

4) “Population genetics of

brown tide blooms.”; lead PI institution: NY University Medical Center, NY

United States

Environmental Protection Agency

Mail Code 8701R

Washington, D.C. 20460

Offical Business

Penalty for Private Use

$300

EPA/600/F-97/025

7) “Chemical ecology of

cyanobacterial blooms on the

tropical reefs of Guam.”; lead PI

instition: University of Guam

8) “Zooplankton grazing of

toxic Alexandrium spp. as a

mechanism in the control of

bloom formation and toxin transfer.”; lead PI institution: University of Rhode Island

9) “Influence of harmful algal

blooms on the distribution and

ecology of high level marine

predators.”; lead PI institution:

California State University,

Monterey Bay

10) “Toxic Ambush-Predator Dinoflagellates - Potential Biosenors

of Estuarine Stress”, Lead PI Institution: North Carolina State

University, North Carolina EPA Funded NOAA Funded NSF Funded