Eukaryotes phytoplankton

Falkowski PG, Katz ME, Knoll AH, Quigg A, Raven JA, Schofield O, Taylor FJR (2004) The evolution of modem eukaryotic phytoplankton. Science 305 354-360 Flynn KJ (2005) Castles built on sand dysfunctionality in plankton models and the inadequacy of dialogue between biologists and modellers. J Plankton Res 27 205-210 Fontana A (2007) Chemistry of oxylipin pathways in marine diatoms. Pure Appl Chem 79 481 490... 

The most abundant compound class found in phytoplankton and bacteria are the proteins. As shown in Table 23.3, proteins make up about half of their dry weight. In comparison to eukaryotic phytoplankton, bacteria are enriched in RNA and DNA. Because proteins and nucleic acids are relatively enriched in nitrogen as compared to carbohydrates and lipids (Table 23.4), bacterial biomass is enriched in nitrogen relative to eukaryotic phytoplankton. 

In the case of eukaryotic phytoplankton, specific prokaryotic inhibitors may be used to block bacterial uptake. The application of this technique in... 

The differences between prokaryotic and eukaryotic phytoplanktonic uptake of iron must affect competition and hence the composition of primary producer communities (Hutchins et al. 1999). The rate of transport of iron into cells depends upon the number of receptors on the membrane surface, so low iron concentrations favour growth of the pi-coplankton, which have a large surface area to volume ratio. 

In particular, it has been suggested that chlorophyll concentrations in the euphotic zone at stations Climax and ALOHA document the impact of PDO, and specifically the climate shift of 1976-77 on oligotrophic gyre productivity (Karl, 1999 Karl etal., 2001b). The current hypothesis suggests a shift from a eukaryotic phytoplankton community to one dominated by nitrogen-fixing prokaryotes. The shift to prokaryotic dominance is caused by physical conditions... 

Eukaryotic phytoplankton do not appear to produce siderophores and there is little evidence for direct cellular uptake of ferric siderophore chelates. Instead there is mounting evidence for the utilization of a high-affinity transport system that accesses ferric complexes via their reduction at the cell surface and subsequent dissociation of the resulting ferrous-ligand complexes. The released ferrous ions bind to iron(ii) receptors on iron transport proteins located on the outer cell membrane, which transport the iron into the cell. This intracellular transport involves the reoxidation of bound iron(ii) to iron(iii) by a copper protein, and thus copper is required for cellular iron uptake. The availability of iron to this transport... 

Zinc chelators also serve a beneficial function, not only by minimizing abiotic scavenging of zinc in surface waters, but also by preventing the extremely efficient uptake systems of eukaryotic phytoplankton from completely depleting this essential micronutrient element from surface ocean waters. 

Phytoplankton - eukaryotic phytoplankton. Zooplankton - including protozoans and metazoans. Abbreviations NH4, ammonium NO2, nitrite NOs particulate organic N organic N, DON and PON. 

The first evidence that cadmium had a beneficial biological function came from growth data in laboratory cultures of the diatom Thalassiosira weissflogii [43,45]. As shown in Fig. 10, cultures of this coastal diatom grow slowly when the unchelated Zn concentration in the medium is reduced to about Zn = 3 pM. pM. These same cultures grow much faster when Cd is added to the medium at unchelated concentrations >5 pM [46]. This effect, which is particularly obvious at low Co concentrations, has now been observed in other families of marine phytoplankton. For example, Cd enhances the growth rate of the cosmopolitan coccolithophore Emiliana huxleyi when the unchelated Zn and Co concentrations in the medium are below 1 pM (Fig. 10) [42]. From similar laboratory studies, it appears that Zn, Cd, and Co can substitute for each other in many marine eukaryotic phytoplankton [47-51]. 

Cuvelier ML, Allen AE, Monier A, McCrow JP, Messie M, Tringe SG, Woyke T, Welsh RM, Ishoey T, Lee J-H. Targeted metagenomics and ecology of globally important uncultured eukaryotic phytoplankton. Proc Natl Acad Sci USA 2010 107(33) 14679-14684. 

Dyhrman, S. X Ruttenberg, K. C. Presence and regulation of alkaline phosphatase activity in eukaryotic phytoplankton from the coastal ocean implications for dissolved organic phosphorus... 

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