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• Can algae just be helpful in the ecosystem, just be harmful, or can it be both? Explain your answer.

A Bloom of a A Bloom of a ““DifferentDifferent”” Color ColorUsing satellite imagery to

monitor coastal algae

Algal BloomsAlgal Blooms• Marine algae form

the base of the ocean food chain

• Coastal nutrient rich waters support a range of algal species

• Population growth is influenced by many factors

Marine Phytoplankton

Zooplankton

Shrimp

FishFish

What is our What is our interest in the interest in the marine algae?marine algae?

How do they How do they affect us?affect us?

National interest• Some species add

DMS (dimethyl sulfide) to the atmosphere

• Satellite algorithms track pockets of high cell counts

• Do the algal cells alter the biogeochemical nature of the area over time?

CoccolithophoreEmiliania huxleyi

National interest• Important Nitrogen

fixer in the oceans• Produces a

neurotoxin that can be involved in fish kills and human illness

• Detection by Wide Field-of-view Sensor (SeaWiFS)

cyanobacteria Trichodesmium

Harmful Algal BloomsHarmful Algal Blooms• The population of

algal cells can increase rapidly

• Some algae produce toxins that can endanger marine animals and humans

• > 5000 species • < 5% are toxic

Many Many different different

algal species algal species are are

responsible responsible for HABfor HAB’’ss

National interest• The water appears

“red” in color – known as the red tide

• Neurotoxin concentrates in shellfish, but can be released from algae through wave action

• Fish kills, marine mammals may die, human concerns

DinoflagellateDinoflagellateKarenia brevis

May 25-Jun 1, 2003

National interest• Formation of

ECOHAB agency for focused research on Harmful Algal Blooms

• Provides greater understanding of algal cell transport, conditions for blooms, and toxicity differences between the speciesCells caught in Gulf Stream fingersCells caught in Gulf Stream fingers

Local Interest• State agencies in

coastal zones monitor the cell counts, notify public of health concerns

• Shellfish and fin fishing may be restricted

• Citizen awareness is increased; action groups are formed

Worldwide Effects of HABWorldwide Effects of HAB’’ss

• Light penetration levels in water decrease altering photosynthesis rate

• Algal blooms may be harmful to seagrass and coral reef ecosystems and the connected food webs

• Shellfish may accumulate algal toxins by feeding on the toxic phytoplankton resulting in fish kills, marine mammal distress, human illness and possible death

Toxins and their EffectsToxins and their Effects

• Compounds will bioconcentrate when ingested at lower trophic levels (algal toxins or phycotoxins are relatively chemically stable to heat and cold)

• Can cause “lesions” on dermis of fish thus providing a path for infection

• Produce symptoms that affect the nervous system and/or intestinal distress; some cardiovascular effects in marine animals and humans

Types of HAB’s/Toxicity

• Brown/red tide

• Amnesic Shellfish Poisoning

• Diarrhetic Shellfish Poisoning

• Neurotoxic Shellfish Poisoning

• Paralytic Shellfish Poisoning

• Ciguatera Fish Poisoning

• Harmful Cyanobacterial Blooms

What do you notice about the incidents

of reported toxic outbreaks?

How can the public become more aware

of this problem?

Frequency of HAB events

Reasons for Increase in HABReasons for Increase in HAB’’ss

• Global climate change producing wider ranges for some species

• Human contributions of increased nutrients and pollution in coastal waters

• Subtle changes in local ecosystems that may allow exotic species to thrive if introduced

• A more comprehensive monitoring and reporting system

Types of Toxicity

Ciquatera Fish Poisoning • Pantropical distribution• Toxins accumulate in reef

fish that may remain toxic for as long as two years

• 50,000 plus victims annually – many unreported incidents

• Gastrointestinal and neurological distress, rarely fatal

• Gambierdiscus taxicus

Neurotoxic Shellfish Poison• Less severe than CFP,

but similar toxic affects• Often blooms discolor the

water and kill fish• Causes respiratory

discomfort like allergies when cells rupture

• Economic impact huge when fisheries are closed

• Karenia brevis or G.breve

Types of Toxicity Types of Toxicity

Paralytic Fish Poisoning • Concentrate in mackerel

on the food chain• PSP is caused by a

saxitoxin• Can cause death in

marine mammals and in humans

• World wide distribution – species below is tropical

• Pyrodinium bahamense

Diarrhetic Shellfish Poison• Symptoms similar to

bacterial gastroenteritis• Not fatal, recovery in

three days• Algal cells found in all

coastal temperate waters • Okadaic acid from

species below caused problems in Japan

• Dinophysis sp.

Types of Toxicity Types of Toxicity

Amnesic Shellfish Poison• First recognized in 1987

on Prince Edward Island• Caused 4 deaths and 100

acute cases from ingestion of blue mussels

• Neurotoxic domoic acid is produced by the diatom below

• Careful monitoring during bloom cycles – wide distribution of this species

• Nitzchia sp.

Can we predict when or where the next algal bloom will occur?

Study proximity of shellfish beds and coastal rivers to high algal cell counts

Watch for the HABWatch for the HAB’’ss

Interactive mapping on-line to examine satellite imagery for SST, winds and chlorophyll-a

http://http://www.csc.noaa.gov/crs/www.csc.noaa.gov/crs/habf/habmaps.htmlhabf/habmaps.html

Predict bloom or not?Predict bloom or not?• Scientists agree that a combination of

factors seem to cause algae to “bloom” in an area

• Satellite technology helps to focus on global and local HAB problem spots

• Prediction capabilities have increased, so the public can be informed earlier about fishing restrictions and health concerns