Marine food web

White GF, NJ Russell, EC Tidswell (1996) Bacterial scission of ether bonds. Microbiol Rev 60 216-232. Yoch D (2002) Dimethylsulfoniopropionate its sources, role in the marine food web, and biological degradation to dimethylsulfide. Appl Environ Microbiol 68 5804-5815. 

Atwell L, Hobson KA, Welch HE. 1998. Biomagnilication and bioaccumulation of mercury in an arctic marine food web insights from stable nitrogen isotope analysis. Can J Fish Aquat Sci 55 1114-1121. 

The above findings would challenge the classical view of marine food web energy flow from diatoms to fish by means of copepods if this defense would be an universal feature of diatoms. In field experiments monitoring diatom abundance (but not food uptake) and hatching success of copepods, only a few... 

Figure 14.3 Isotopic map of terrestrial and marine food webs (adapted from O Connell 1996)...

Entering into the Caspian Sea, as an undischarged water body, the toxicants will migrate for a long time, owing to prevalence of water circulation, and bioconcentrate in marine food webs, the final link of which is a human. 

How fevored is this reaction How much H2S should be present at equilibrium These are important questions because H2S appears to be a major source of chemical energy supporting the hydrothermal marine food web. 

Although phototrophs are restricted to the surface ocean, photosynthesis is the ultimate source of almost all the organic matter that supports heterotrophic activity in the sea. As shown in Figure 8.1, this organic matter is transferred through the marine food web by the feeding activities of heterotrophs including bacteria, protozoans, and animals. 

Halogenated bipyrroles bioaccumulated in the marine food web. Source From Teuton, E. L., et al. 

Some is released into seawater as an extracellular exudate or as a result of viral lysis and from sloppy feeding by the grazers. Consumption by grazers entrains the organic matter in the marine food web as shown in Figure 23.2. Cells that are not consumed or lysed by a virus can sink or be otherwise carried out of the euphotic zone by currents. 

The inefficiency of microbial heterotrophy does have a side benefit as it enhances nutrient remineralization rates. This serves to increase the availability of inorganic nitrogen and phosphorus for the photoautotrophs. The multiple roles of bacteria in the marine food web were shown in Figure 23.2, with the component of the food web controlled by the algal herbivores depicted on the left side and the microbial loop on the right. The viral shunt acts on both pathways. 

Nutrient pollution has contributed to other notable disturbances in the structure of marine food webs. These include (1) bioinvasions of macroalgae and microbial mats... 

MMHg is UpophiUc, causing it to bioaccumulate and biomagnify through the marine food web. About 85 to 95% of the total mercury in fish is MMHg, most of which is the result of biomagnification. Marine fish consumption accoimts far most of the mercury burden in... 

Borga, K., Fisk, A.T., Hoekstra, P.F. and Muir, D.C.G. (2004) Biological and chemical factors of importance in the bioaccumulation and trophic transfer of persistent organochlorine contaminants in Arctic marine food webs. Environ Toxicol Chem, 23, 2367-2385. 

H., Solomon, K.R. and Muir, D.C.G. (2003) Enantiomer-specific biomagnification of alpha-hexachlorocyclohexane and selected chiral chlordane-related compounds within an Arctic marine food web. Environ Toxicol Chem, 22, 2482-2491. 

Tittlemier SA, Fisk AT, Hobson KA, Norstrom RJ (2002) Examination of the Bioaccumulation of Halogenated Dimethyl Bipyrroles in an Arctic Marine Food Web Using Stable Nitrogen Isotope Analysis. Environ Pollut 116 85... 

Corsolini, S., Kannan, K., Imagawa, T., Focardi, S., Giesy, J.P., 2002. Polychloronaph-thalenes and other dioxin-like compounds in Arctic and Antarctic marine food webs. Environ. Sci. Technol. 36, 3490-3496. 

Concentrations of Chlordanes (sum of a- and y-) are higher than reported values for other marine food webs in the Baltic Sea (Falandysz et al., 2001). Chlordane concentrations in mangrove fish correspond to the upper range of what has been recorded in various species of fish elsewhere in the Asia-Pacific region (UNEP, 2002). The Chlordane profile was dominated by a- and y-Chlordane in all samples except for crabs and gobies. Falandysz et al. (2001) also noted differences in Chlordane levels between crabs and other marine organisms which were attributed to the potency of crabs to metabolize Chlordane into Oxychlordane. 

Fry, B., and Wainwright, S.C. (1991) Diatom sources of 13C-rich carbon in marine food webs. Mar. Ecol. Prog. Ser. 76, 149-157. 

The haptophyte Phaeocystis is a dominant phytoplankton genus in tropical to polar seas (Baumann et al. 1994). They are key species in marine food webs and biogeochemical cycles, e.g., as major producers of carbon and climatically important sulfide compounds (Liss et al. 1994 Alderkamp et al. this volume Stefels et al. this volume). Three major species P. globosa Scherffel, P. pouchetii (Hariot) Lag-erheim and P. antarctica Karsten (Medlin and Zingone this volume) exist in two main morphotypes small single cells and mucilaginous colonies (see Rousseau et al. this volume for details on the different cell and morphotypes). 

---