Holoplankton Meroplankton Holoplankton are always plankton – they live and die in the water column Meroplankton are only plankton for part of their lives many marine organisms begin their lives as small planktonic organisms, but gain the ability to swim or metamorphose into a benthic organism Most are planktonic, but others form symbiotic relationships with coral (zooxanthellae) and giant clams Flagella for movement Responsible for red tides (harmful algal blooms)Ĭaused by dinoflagellates and other small flagellatesĢ3 Zooplankton Zooplankton are the most numerous primary consumers in the ocean The most important source of protein in the oceans! Zooplankton eat bacteria, phytoplankton, and other zooplankton! Nearly every major animal group is represented in the zooplanktonĢ4 Zooplankton Zooplankton are classified as either: Important source of nutrition for zooplankton √Ģ0 Dinoflagellates Can be autotrophic or heterotrophic! Localized primary productivity occurs seasonally, accompanied by physical changes to the water column In temperate regions, primary productivity is limited by light (winter) and by nutrients (summer) Peak productivity occurs during spring, in an abundance of phytoplankton known as a “spring bloom”ġ4 Primary Productivity in Temperate Regionsĭuring winter, nutrients are at their highest, but light is at its lowest In spring, solar energy reaching the photic zone increases and nutrients are still abundant In summer, strong warming of the water creates a seasonal thermocline which restricts nutrients from reaching the photic zone In fall, storms enhance mixing, and a second seasonal bloom resultsġ6 Compensation Depth Net primary productivity is the amount of carbon dioxide removed via photosynthesis minus the amount of carbon dioxide released by respiration Compensation depth refers to the depth in the water column at which the rate of photosynthesis equals the rate of respiration Above this depth, phytoplankton survive Below this depth, phytoplankton dieġ8 Phytoplankton Phytoplankton are mostly single-celled algae (Kingdom Protista) There are 8 major types of phytoplankton, 2 of which are most prominent: Diatoms Dinoflagellatesġ9 Diatoms √ Dominant (>5,600 species) Composed of silica shells In tropical regions, there is plenty of sunlight but productivity is limited by nutrients trapped beneath the thermocline In polar regions, there are plenty of nutrients, but sunlight (and sinking out of the photic zone via mixing) limits productivity In temperate regions, the combination of sunlight and nutrients is just right, but only seasonally!ġ2 Primary Productivity in Temperate Regions Gelatinous zooplankton, for example)Ħ Phytoplankton Phytoplankton are responsible for 40% of all the world’s photosynthetic food on Earth (and 95% of all the ocean’s!) Provide ~one half of all the oxygen we breathe! Collectively, the production of organic compounds from CO2 is referred to as primary productivityħ Phytoplankton Phytoplankton require nutrients, especially nitrogen and phosphorus (macronutrients) but also iron (micronutrients) For this reason, phytoplankton appear in abundance (“blooms”) in regions of upwelling, where cold, nutrient-rich water reaches the photic zone holoplankton) By Taxonomy (Crustaceous vs. heterotrophic) By Life History (meroplankton vs. 1 Plankton Marine life is classified into three groups: Plankton, Nekton, and Benthos Plankton Nekton BenthosĢ Plankton Plankton refers to the drifting organisms within the pelagic zone Phytoplankton are autotrophic, photosynthetic algae, which form the base of the marine food web Zooplankton are heterotrophic the primary (and in some cases secondary and tertiary) consumers of the marine food webģ Plankton form the base of the marine food webīy Metabolism (autotrophic vs.
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