Biological Productivity

GAUTAM SANKA

Phaeophyta (Brown Algae)• Largest members of the marine plant community that

are attached to the bottom in the littoral and inner sublittoral zones.

• Dominant pigment is fucoxanthin• Occurs primarily in temperate and cold water areas• Examples include Ralfsia and Pelagophycus(bull kelp)• Sargasum is a genus of brown algae which may be at

the bottom of shore waters or floating freely. – Commonly found in the Sargasso Sea

• Fucales, an order in phaeophyta, is found near rocky shores

Chlorophyta

• Division of green algae that is mostly found in freshwater and not much in the oceans

• They are mostly intertidal and grow in shallow waters of bays

Rhodophyta (Red Algae)

• Red algae are very abundant but rarely found in freshwater

• Pigment is phycoerythrin• In warm water, algae tends to be relatively

small in comparison to algae in cold water• color of red algae varies on the depth in the

intertidal or inner sublittoral zones

Spermatophyta (seed-bearing plants)

• Two that exist in the marine environment are Zostera (eelgrass) and Phyllospadix (surf grass)

• Eelgrass– Grass with true roots and is found primarily in quiet

waters of estuaries and bays• Surf Grass– Prefers the high energy environment of an exposed

rocky coast• Both of these plants are considered to be

important sources of detritus food for the marine animals

Pyrrophyta (Dinoflagellate Algae)• Using their flagella, these organisms tend to move into

favorable areas for plant productivity• Most don’t have protective covering and if they do, it is

made of cellulose. Many are luminescent• Red tides result from conditions where up to 2 million

dinoflagellates may be found in one liter of water– Mainly responsible for this red tide phenomenon are the

following which create toxins – Gymnodinium toxin kills fish and shellfish.

• Contributor to Gulf of Mexico red tides– Gonyaulax toxin is not poisonous to shellfish but will

concentrate in their tissue and is poinsonous to humans who eat the shell fish• Contributor of cooler waters of the New England and West Coast Area

Chrysophyta (Golden Algae)• Containing pigment carotin and store food in

form of leucosin (a carb)• Diatoms are plants that are in a shell, fristule,

composed of SiO2– These silica housings accumulate on the ocean

bottom and produce a siliceous sediment, diatomite– The top and bottom are called valves; larger valve is

epitheca and the smaller valve is hypotheca– Reproduction is simple cell division except an

auxospore is formed to grow into a full sized diatom when the original can’t split anymore

Chrysophyta Contn.

• Coccolithophores are flagellated organisms covered with small calcareous plates, coccoliths made up of CaCO3– Are included as nanoplankton– Contribute significantly to calcareous deposits in

all of the temperate and warmer oceans