Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
37 Cards in this Set
- Front
- Back
|
Well- lit surface water often lacks nutrients in the ocean |
- light dissapates rapidly as you go deeper (BEERE'S LAW) - Exponential decay - nutrients are not at the top, decomp takes pace in deeper water (oceans are stratified) |
|
|
Sinking and density stratification combine to sequester nutrients in deep waters |
- warm surface ocean- primary producers take in No3 and PO4 -Cold deep waters have bacterial deposition of these ions - Nutrients return to the photic zone by convective mixing and upwelling and by a variety of mixing processes in the costal ocean |
|
|
Each place in the ocean produces the same amount of organic matter |
-upwelling- ekman transport: high productivity rates -costal- receive nutrients from land and also bottom is closer to water, easier to mix- higher productivity -Open ocean- low productivity but lots of area! |
|
|
Global primary production on land and in the ocean is similar |
-land is higher productivity than ocean, but they are ALMOST EQUAL! |
|
|
Marine Photosynthesis -many organisms photosynthesize |
- Pelagic phytoplankton - pelagic cyanobacteria - benthic microalgae - benthic macroalgae (kelp and seaweed) - Seed plants (sea grasses, mangroves, salt mash plants) - Symbiotic dinoflagellates in corals |
|
|
Few groups account for perhaps 95% of all marine primary productivity |
- pelagic plankton - pelagic cyanobacteria - other presently undescibed aerobic photoheterotrophs |
|
|
Unlike on land, the dominant primary producers in the ocean are small |
- most are green because that is the wavelength that is not used! |
|
|
Phytoplankton in the ocean are diverse, comprising all 3 domains of life: -archaea -bacteria -eukarya |
- Phyto light harvesters - Plankton float, but no not swim - Archaea, bacteria, and Euka have all figured out how to harvest light independently. |
|
|
Archaea are found in extreme conditions, BUT ALSO everywhere else |
-lack cell structures, found in extreme envionments (like hot springs and hydrothermal vents) -left over organisms from the dawn of life -are found in the upper ocean and capable of primative photosynthesis -abundant but poorly understood |
|
|
Bacteria's Role in the Ocean |
- Cyanobacteria are also known as blue green algae (biggest marine bacteria group) - are important primary producers, responsible for oxygenating the atmosphere 3.5 billion years ago! - nitrogen fixers - Stromatolites- calcium carbonate structure that are produced by cyanobacterria secretion needed in nutrient poor areas because they can fix nitrogen into a usable form! |
|
|
Cyanobacteria are found in many environments: |
- sea water - fresha water - terrestrial soils - are rock - FOUND EVERYWHERE, slimy film on rocks |
|
|
Trichodesmium is common in nutrient poor waters |
- makes water look red (over vast differences) - this could be why the red sea is called the red sea |
|
|
Cyanobacteria "Synechoccus" - are one of the most abundant phytoplankton taxa in the ocean |
- Tiny: 1 um
- account for sign. faction of glabal primary production - about 50% of global production - conventional "phytoplankton" has been filtered out, but they were still found in the water. |
|
|
Prochlorococcus- even smaller and more abundant |
-smallest known synthetic organism, with idameter of 0.3 um -most abundant phytoplankton yet discovered -may account for more than half of marine primary production -discovered in the 1980's -responsible for >50% photosyntheis production -medical technologies- illuminates them |
|
|
Tiny Critters |
-cyanobacteria (yellow) -heterotrophic and phototrophic bacteria -viruses (too tiny to see)- waiting to bump into cell |
|
|
Eukaryotic phytoplankton are important to marine food webs |
-larger -better described -nucleus!!!! -organelles -important in fresh water even more than salt waters! -are green algae in marine waters! |
|
|
The large range in size of phytoplankton has lead to a classification scheme based on size!!! |
-large range! Nanoplankton can be caught in nets Femtoplankton(0.02-0.2 mm);Picoplankton(0.2-2 mm);Nanoplankton(2-20 mm);Microplankton(20-200 mm);Mesoplankton(0.2-2 mm);Macroplankton(2-20 mm);Megaplankton(20-200 mm). |
|
|
Nanoflagellates |
-name is from size and taxa - very diverse group (2-20 um) -have flagella, some are heterotrophs and others are autotrophs -as heteroptrophs, allow for nutrients to get out of nutrient look. |
|
|
Classification based on taxonomy is more common |
-silicoflagellates} -coccolithophores -diatoms} THESE ARE CRYSOPHYTES -dinoflagellates |
|
|
Silicoflagellates are enigmatic |
-unicellular -common and beautiful -source of silicous oozes (30% of weight make up -havent been studied because they dont contribute much |
|
|
Coccolithophores are enigmatic |
-unicellular -common -bloom over large expanses, casting off coccoliths, which reflect light and make lighter sections of the ocean! -key source of calcareous oozes (by england) |
|
|
Diatoms |
-can be big -have radial symmetry -penidiatoms (bilateral symmetry) -silica is denser than water -makes clunky shells, but do not sink because of oil drops inside of them (uplifting zones) -some swim, some are motile |
|
|
Frustules are denser than water! |
-diatoms have mechanisms to stay in the surface water! -internal oil droplets -entrainment in upwelling water -swimming -structures that increase drap |
|
|
Silica Frustules evolved? |
-defensive against grazers and viruses -focuses light on chloroplasts (all 3 are needed) |
|
|
Diatoms reproduce rapidly via asexual reproduction |
-good at reproducing asexually -sexual reproduction also occurs |
|
|
Limitations of Asexual reproductions |
- diminution of cell size -no exchange of genetic information -sexual reproduction does occur but not at every generation |
|
|
Asexual reproduction |
-when conditions are right, can lead to exponential growth |
|
|
Dinoflagellates are the last major group of phytoplankton |
-two flagellum allow for weak swimming -large like dinoflagellates are armoured with cellulose plates -Athecate dinoflagellates are unarmoured and naked |
|
|
Dinoflagellates cannot be classified as phytoplankton |
-some are autotrophs -some are heterotrophs -some are mixotrophs |
|
|
Some general trends in phytoplankton ecology exist |
-diatoms bloom in nutrient-rich waters in the spring -dinoflagellates follow, thriving in lower nutrient conditions -large cells are more common in nutrient rich waters |
|
|
Phytoplanton require nutrients and light |
-challenges of light and nutrients, need to be under P-max, too much light burns the cells, but also at an area where there is alot of nutrients for biomass |
|
|
Challenges for photosynthetic autotrophs differ on land and water |
- nutrients must be obtained from the surrounding water, avoid shading |
|
|
Small size is key to aquiring light and nutrients in the surface ocean |
-smaller size leads to large surface area to volume ratio -large surface area leads to a slower rate of sinking -enhaces nutrient uptake, rate per unit of body volume |
|
|
Stokes LAW |
-appropriate for slowly sinking spheres, small size and density should be nnear to that of the water to favour flow sinking |
|
|
Fine mesh can be used to study phytoplankton |
-fine mesh on them, funnels into a cup |
|
|
Estimating biomass- often the primary goal |
- chlorophyll fluoresces -chlorophyll concentration is directly related to biomass -can be extracted into a solution -fluoroscence of the solution can be measured in a fluorometer |
|
|
SUMMARY SLIDES |
SUMMARY SLIDES OF PHYTOPLANKTON |
