Marine Biology Plankton

General Info: Plankton comes from the Greek word “planktos” which means drifter. Plankton comes from the Greek word “planktos” which means drifter.

Movement Most organisms move with the current. Some have the ability to move on their own. For example, copepods are the fastest animal for their size- they move more than 500 body lengths per second. Most organisms move with the current. Some have the ability to move on their own. For example, copepods are the fastest animal for their size- they move more than 500 body lengths per second.

Two Types of Plankton Phytoplankton- which are autotrophs (plank- like) Phytoplankton- which are autotrophs (plank- like) Zooplankton- which are heterotrohs (animal-like) Zooplankton- which are heterotrohs (animal-like)

Location- Epipelagic region of the ocean: This location is near the surface where the water is warmer and lighter. This location is near the surface where the water is warmer and lighter. The depth is from the surface to 200m or 650 ft. The depth is from the surface to 200m or 650 ft. It often corresponds with the photic zone, the is the region where light penetrates. It often corresponds with the photic zone, the is the region where light penetrates.

Location: Epipelagic region of the ocean (con’t) Shallowest part of the pelagic realm Shallowest part of the pelagic realm The pelagic realm is the vast open ocean away from the bottom and the shore The pelagic realm is the vast open ocean away from the bottom and the shore

Location: Epipelagic region of the ocean (con’t) Coastal/neritic: are waters that lie over the continental shelf (small portion of the epipelagic) Coastal/neritic: are waters that lie over the continental shelf (small portion of the epipelagic) Oceanic: are surface waters beyond the continental shelf. Oceanic: are surface waters beyond the continental shelf.

Location: Epipelagic region of the ocean (con’t) This area lacks deposit feeders since there is NO bottom This area lacks deposit feeders since there is NO bottom Suspended feeders are therefore ABUNDANT Suspended feeders are therefore ABUNDANT None of these deposit feeders! None of these deposit feeders!

All energy comes from the sun: Nearly all primary producers (photosynthesis) from the ocean occurs in the epipelagic zone Nearly all primary producers (photosynthesis) from the ocean occurs in the epipelagic zone Food produced sinks or is carried by the currents to other parts of the ocean. Food produced sinks or is carried by the currents to other parts of the ocean. Autotrophs carry out photosynthesis by taking in carbon dioxide and converting it to organic food (glucose) Autotrophs carry out photosynthesis by taking in carbon dioxide and converting it to organic food (glucose)

Plankton have trouble remaining afloat: Organisms and their shells are more dense than water and therefore should sink Organisms and their shells are more dense than water and therefore should sink Coping strategies: Coping strategies: –Increase water resistance- the greater the surface area the more resistance –Being small is helpful –Flat shape also increases surface area, as do projections and spines

Plankton have trouble remaining afloat (con’t): Coping strategies (con’t) Coping strategies (con’t) –Increase buoyancy Some store lipids as vacuoles of oil (less dense than water) Some store lipids as vacuoles of oil (less dense than water) Some use pockets of gas which is less dense than water Some use pockets of gas which is less dense than water –Regulating the amount of gas can move the organism up and down the water column Exchange heavy ions for lighter ones Exchange heavy ions for lighter ones

Vertical Migration Predators abound the epipelagic. Therefore, some zooplankton sink where there is little light during the day and rise to feed at night Predators abound the epipelagic. Therefore, some zooplankton sink where there is little light during the day and rise to feed at night

Recent Research New methods to count and identify phytoplankton biodiversity New methods to count and identify phytoplankton biodiversity –Flow cytometry is optical technique that can process hundreds of thousands per minute MIT researchers discovered tiny but abundant new species called prophlorophytes MIT researchers discovered tiny but abundant new species called prophlorophytes DNA research to understand evolution and relationships among plankton DNA research to understand evolution and relationships among plankton

Phytoplankton Photosynthetic Autotrophs Photosynthetic Autotrophs –Greater than 95% of photosynthesis in the ocean –Produce nearly 50% of the oxygen in our atmosphere –Primary producer in the epipelagic- WHY? Gouped by size Gouped by size –Picoplankton- too small to be caught in nets –Net plankton- (micro, meso, macro, nano), large enough to be caught in nets

Phytoplankton (con’t) 2 Main Types 2 Main Types –Diatoms Kingdom Protista Kingdom Protista Have characteristics of both plants and animals Have characteristics of both plants and animals Prefer temperate, polar, and nutrient-rich water Prefer temperate, polar, and nutrient-rich water They are unicellular, although some gather in chains or clusters They are unicellular, although some gather in chains or clusters Enclosed in a cell wall that is made out of silicon dioxide Enclosed in a cell wall that is made out of silicon dioxide

Phytoplankton (con’t) –Diatoms (con’t) They have a glasslike frustules which is a shell with tight- fitting halves. There is a wide variety of beautiful frustules! They have a glasslike frustules which is a shell with tight- fitting halves. There is a wide variety of beautiful frustules! –Some frustules have perforations and spines that allow light to pass through and gasses and nutrients to enter and leave –Frustules from dead diatoms accumulate on the ocean bottom and are called diatomaceous ooze –Fossilized sediments of the ooze found inland are mined as diatomaceous earth which is used for polishing (toothpaste), insulating, and filtering (swimming pools)

Phytoplankton (con’t) –Diatoms (con’t) Reproduce rapidly when conditions are good. Other species are depend on this and it influences the success of some fish species. Reproduce rapidly when conditions are good. Other species are depend on this and it influences the success of some fish species.

Phytoplankton (con’t) Second type Second type –Dinoflagellates Kingdom Protista Kingdom Protista Most abundant phytoplankton in warm, tropical waters Most abundant phytoplankton in warm, tropical waters Unicellular with a cell wall made of cellulose plates Unicellular with a cell wall made of cellulose plates Most outstanding characteristic: 2 unequal flagella Most outstanding characteristic: 2 unequal flagella –One wraps around the groove in the middle of the cell –One trails free –They both direct movement in practically any direction

Phytoplankton (con’t) –Dinoflagellates (con’t) Unique DNA remains coiled in chromosomes throughout life Unique DNA remains coiled in chromosomes throughout life Although autotrophic they also feed on other food particles Although autotrophic they also feed on other food particles Reproduce by cell division Reproduce by cell division –Huge surges of reproduction are called blooms –They produced the Red Tides which actually turned the water red to red-brown

Phytoplankton (con’t) –Dinoflagellates (con’t) –2 Problems with Red Tides  Produce toxins which may cause fish to die or accumulate in the tissues of resistant organisms which can result in paralytic shellfish poisoning which can be fatal to humans  As the bloom dies and decomposes, the bacteria deplete the dissolved oxygen form the water causing fish to die

Phytoplankton (con’t) –Dinoflagellates (con’t) Some species produce light by Bioluminescence which can be seen at night in the open ocean Some species produce light by Bioluminescence which can be seen at night in the open ocean Some species celled zooanthellae live in symbiotic relationships with other marine organisms such as coral. They release organic matter used by the coral and help in the formation of the coral skeleton. Some species celled zooanthellae live in symbiotic relationships with other marine organisms such as coral. They release organic matter used by the coral and help in the formation of the coral skeleton.

Phytoplankton (con’t) Nanoplankton Nanoplankton –Very small and hard to catch –Still important in ocean primary production –Two types Cyanobacteria Cyanobacteria Coccolithophorids Coccolithophorids

Phytoplankton (con’t) Nanoplankton (con’t) Nanoplankton (con’t) Cyanobacteria Cyanobacteria –Kingdom Monera, therefore prokaryotic –Contain chlorophyll (green pigment) and phycocyanin (blue pigment) –Most are microscopic, but can form long visible strands or mats –Likely the first photosynthetic organisms on Earth and contributed to the accumulation of oxygen in the atmosphere –Can also carry out nitrogen fixation- converting atmospheric nitrogen gas to usable from alike ammonia

Phytoplankton (con’t) Nanoplankton (con’t) Nanoplankton (con’t) Coccolithophorids Coccolithophorids –Covered with rounds calcium carbonate paltes

Zooplankton Tiny planktonic animals Tiny planktonic animals A few species are a critical link in the food web- they are herbivores, meaning they eat autotrophs A few species are a critical link in the food web- they are herbivores, meaning they eat autotrophs Most are carnivorous and feed on the herbivorous zooplankton Most are carnivorous and feed on the herbivorous zooplankton

Zooplankton (con’t) They are divided into two groups: Holoplankton and Meroplankton They are divided into two groups: Holoplankton and Meroplankton –Holoplankton: spend their entire lives a plankton Copepods Copepods –Most abundant zooplankton (70% or more) and may be the most abundant animal on Earth –The are crustaceans –Most eat phytoplankton and zooplankton (use bristled antennae) –Move fast to escape predators

Zooplankton (con’t) –Holoplankton (con’t) Krill Krill –Shrimp-like crustaceans –Prefer colder waters –Filter feeders, eat diatoms, detritus, and zooplankton

Zooplankton (con’t) –Holoplankton (con’t) Other holoplankton Other holoplankton –Salps- related to sea squirts –Larvaceans- also related to sea squirts and secrete a house of mucus –Pteropods- small snail-like creatures with modified foot to make wing-like projections –Arrow worms (chaetognaths)- feed on copepods

Zooplankton (con’t) –Meroplankton: Only a portion of the lives are spent as plankton (larva of fish and invertebrates) Veligers- mollusks Veligers- mollusks Ophiopluterus- brittle stars Ophiopluterus- brittle stars Bipinnaria- sea stars Bipinnaria- sea stars Trpchophore- polychaete worms and some mollusks Trpchophore- polychaete worms and some mollusks Nauplius- crustaceans Nauplius- crustaceans