News Update on Phytoplankton Research: Dec – 2019

Phytoplankton Size

In reviewing this subject, it became clear to me that plankton ecologists fall out into two groups: those that enjoyment of finding the patterns in nature which will be explained by size, and people who enjoyment of finding exceptions to the established size-dependent rules. I came to understand the degree to which the satisfaction of both groups is equally justified. The mechanisms underlying the size-dependent patterns have undoubtedly steered the overall course of phytoplankton evolution, but the organisms that don’t abide by the principles reveal the wonderful diversity of the way during which cells have managed to disobey the “laws” scripted for them. [1]

The Evolution of Modern Eukaryotic Phytoplankton

The community structure and ecological function of up to date marine ecosystems are critically hooked in to eukaryotic phytoplankton. Although numerically inferior to cyanobacteria, these organisms are liable for the bulk of the flux of organic interest higher trophic levels and therefore the ocean interior. Photosynthetic eukaryotes evolved quite 1.5 billion years ago within the Proterozoic oceans. However, it had been not until the Mesozoic (251 to 65 million years ago) that the three principal phytoplankton clades that might come to dominate the fashionable seas rose to ecological prominence. In contrast to their pioneering predecessors, the dinoflagellates, coccolithophores, and diatoms all contain plastids derived from an ancestral red alga by secondary symbiosis. [2]

Hydrocarbons of marine phytoplankton

The hydrocarbon contents of 23 species of algae (22 marine planktonic), belonging to 9 algal classes, were analyzed. The highly unsaturated 3,6,9,12,15,18-heneicosalhexaene predominates within the Bacillariophyceae, Dinophyceae, Cryptophyceae, Haptophyceae and Euglenophyceae. Rhizosolenia setigera contains n-heneicosane, presumably derived from the hexaolefin by hydrogenation. Two isomeric heptadecenes are isolated: the covalent bond is found in 5-position within the bluegreen alga Synechococcus bacillaris and in 7-position in 2 chlorophyte. Our complete analyses are discussed within the context of earlier data; some generalizations appear not valid. Hydrocarbon analysis of marine algae should provide a tool for the investigation of the dynamics of the marine organic phenomenon. [3]

Nitrogen enrichment leads to changing fatty acid composition of phytoplankton and negatively affects zooplankton in a natural lake community

Secondary production in freshwater zooplankton is usually limited by the food quality of phytoplankton. One important parameter of phytoplankton food quality are essential polyunsaturated fatty acids (PUFAs). Since the carboxylic acid composition of phytoplankton is variable and depends on the algae’s nutrient supply status, inorganic nutrient supply may affect the algal PUFA composition. Therefore, an indirect transfer of the consequences of nutrient availability on zooplankton by changes in algal PUFA composition is conceivable. While the phosphorus (P) supply in lakes is essentially decreasing, nitrogen (N) inputs still increase. [4]

Determination of PSP Toxins in Moroccan Shellfish by MBA, HPLC and RBA Methods: Links to Causative Phytoplankton Alexandrium minutum

Paralytic shellfish poisoning (PSP) toxins are secondary metabolites of the toxic species of phytoplankton. The consumption of shellfish accumulating these toxins can cause neurological symptoms and even death. Within the framework of the surveillance program of seafood safety along the Moroccan littoral environment established by National Institute of Fisheries Research (INRH), a study of PST was conducted from 2004 to 2016 in south Moroccan’s shellfish, mussels from south Agadir region and Razor Shell from Dakhla bay. The surveillance was administered bi-monthly or weekly using the AOAC official method of study (AOAC 959.08) mouse bioassay (MBA). In parallel, monitoring of toxic phytoplankton in water was conducted. [5]

Reference

[1] Chisholm, S.W., 1992. Phytoplankton size. In Primary productivity and biogeochemical cycles in the sea (pp. 213-237). Springer, Boston, MA. (Web Link)

[2] Falkowski, P.G., Katz, M.E., Knoll, A.H., Quigg, A., Raven, J.A., Schofield, O. and Taylor, F.J.R., 2004. The evolution of modern eukaryotic phytoplankton. science, 305(5682), (Web Link)

[3] Blumer, M., Guillard, R.R.L. and Chase, T., 1971. Hydrocarbons of marine phytoplankton. Marine Biology, 8(3), (Web Link)

[4] Nitrogen enrichment leads to changing fatty acid composition of phytoplankton and negatively affects zooplankton in a natural lake community
Gabriele Trommer, Patrick Lorenz, Ameli Lentz, Patrick Fink & Herwig Stibor
Scientific Reports volume 9, (Web Link)

[5] Abouabdellah, R., Bennouna, A., Y. Dechraoui-Bottein, M.-, El Attar, J., Dellal, M., Mbarki, A., Alahyane, M. and Benbrahim, S. (2018) “Determination of PSP Toxins in Moroccan Shellfish by MBA, HPLC and RBA Methods: Links to Causative Phytoplankton Alexandrium minutum”, International Journal of Biochemistry Research & Review, 21(2), (Web Link)

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