Nanophytoplankton
Nanophytoplankton are particularly small
Ecosystem role
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Phytoplankton form the beginning of the food chain for aquatic animals. Zooplankton and krill feed on nanophytoplankton, and are then eaten by whales, seals, birds, fish, squid, and other organisms.[2]
Life cycle
Populations are low in the winter, when nutrients are high, and then the populations increase as the nanophytoplankton consume nearly all of the nutrients, reach their carrying capacity, and decline in number at the end of the summer, beginning the cycle again in the winter. However, nanophytoplankton have different seasonal cycles depending on which oceanic biome of the world they live in.[2][3]
Nutrient uptake
Phytoplanktons' density (1.02 g/cm3) is higher than that of sea water (1.00 g/cm3). Therefore, they sink in the ocean, unless there is an upward movement of water. However, nanophytoplankton, with as small as a 1 µm radius, can swim in the ocean, but at a very slow rate, like "a human swimming in molasses". In either case, movement of water past the organism is created, allowing it to grab nutrients passing by. To supply nutrients through their boundary layer, nanophytoplankton employ diffusion more effectively than swimming, however.[2][3][4]
In Antarctic
In the Southern Ocean in the Antarctic zone, nanophytoplankton are the most abundant type of plankton in terms of number, but not volume. Antarctic marine flora consists almost entirely of algae, with phytoplankton (and, therefore, nanophytoplankton as the most numerous type) having great importance. Nanophytoplankton growth has been seen in pack-ice, covering nearly 73% of the Southern Ocean by the end of the winter. They even grow on icebergs. Nanophytoplankton production is affected by light intensity and duration, ice, surface water stability, and currents. Also, availability of silicates, a nutrient for the organism, can affect photosynthetic efficiency and cell composition.[5] Nanophytoplankton also require vitamins. They thrive in areas of shallow water where there is upwelling and mixing. Although optimal growth for the species occurs in water 5–7 °C (41–45 °F), growth still occurs in Antarctic waters, which can reach as low as −2 °C (28 °F). Limitation of light intensity and duration is another factor for survival. In Antarctica, the sun's lower position above the horizon reduces light due to increased reflection, and the stormy seas reduce transmission of light due to bubble formation. However, some Antarctic nanophytoplankton seem to be adapted to low light levels. Most phytoplankton exist in warmer, equatorial waters. For example, in the northwestern Philippine Sea, the average number of nanophytoplankton was 1x104/l. Nanophytoplankton in particular seem to survive better under the conditions provided by the oceans of the Antarctic. A physiological change in the cells must have occurred to allow this phenomenon. Low salinity is desirable for survival, as well.[6]
Effect on global warming
Continued
See also
References
- ^ phytoplankton Dictionary.com
- ^ a b c "News in Science - Phytoplankton implicated in global warming - 27/11/2002". www.abc.net.au. Retrieved 21 September 2018.
- ^ a b Stonehouse, B. Polar Ecology. New York: Chapman and Hall, 1989.
- ^ Mann, K. H. and Lazier, J.R.N. Dynamics of Marine Ecosystems III. Australia: Blackwell Publishing, 1991.
- ^ Laws, R. M. Antarctic Ecology. Orlando: Academic Press Inc., 1984
- ^ Schmitt, Waldo and Llano, George. Biology of the Antarctic Seas XI. Washington D.C.: American Geophysical Union, 1971.
- ^ "Global Warming and Ozone Depletion". ess-home.com. Archived from the original on 16 March 2010. Retrieved 21 September 2018.
External links
- http://sherpaguides.com/georgia/barrier_islands/images/Phytoplankton.gif
- http://www.visindavefur.hi.is/myndir/phytoplankton_070305.jpg