bio155_lecture_8_Phytoplankton&Zooplankton

bio155_lecture_8_Phytoplankton&Zooplankton - BIOE...

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Phytoplankton and Zooplankton (AKA; Small freshwater organisms) (read pp 65-78; 85-106 in Dodson) “There is probably no almost complete list of species of animals and plants available for any lake, but it would seem likely from the several hundred species of diatoms and insects known from certain lakes that a species list of the order of a thousand entries may be not unusual.” G.E. Hutchinson 1965. Background Plankton —organisms that live up in the water column, and are subjected to the control of the movement of water. There are several key consequences of being small: Movement is dominated by viscous forces (Reynolds number) Surface to volume ratio is a function of size. o Smaller size Æ increased surface:volume ratio o Therefore, smaller cells can do better in low nutrient conditions Feeding type: Autotrophic— organisms that get their energy from the sun using photosynthesis (for example, plants, phytoplankton). Heterotrophic— organisms that extract their energy from organic substances (for example; fish, zooplankton, fungi). “BACTERIA” Smallest (<2 micron) Prokaryotes Energy consumption: This group includes organisms that photosynthesize (such as Cyanobacteria (blue-green bacteria/algae)), as well as other bacteria that utilize organic molecules and are heterotrophs. Heterotrophs— consume organic matter Photoheterotrophs —use light energy to help uptake/metabolize dissolved organic matter. Chemoheterotrophs —metabolize organic matter without the help of light. Photoautotrophs (e.g., cyanobacteria such as Aphanizomenon)—can photosynthesize. Prokaryotes are: Single-celled organisms Lack intracellular organelles (such as a nucleus) Are often heterotrophic (break down energy-rich compounds). Found as:
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bio155_lecture_8_Phytoplankton&amp;amp;Zooplankton - BIOE...

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