Trophic chains

It has been recognized for some time that fluids in motion, such as the atmosphere or the ocean, disperse added materials. This properly has been exploited by engineers in a variety of ways, such as the use of smoke stacks for boiler furnaces and ocean ontfalls for the release of treated wastewaters. It is now known that dilution is seldom the solution to an enviromnental problem the dispersed pollutants may accumulate to undesirable levels in certain niches in an ecosystem, be transformed by biological and photochemical processes to other pollntants, or have nnanticipated health or ecological effects even at highly dilute concentrations. It is therefore necessary to rmderstand the transport and transformation of chemicals in the natural environment and through the trophic chain ctrlminating in man. 

Fig. 6. Deuterium enrichment through a conceptual trophic chain.

Correa-Reyes G, Viana MT, Marquez-Rocha FJ, Licea AF, Ponce E, Vazquez-Duhalt R (2007) Nonylphenol algal bioaccumulation and its effect through the trophic chain. Chemosphere 68 662-670... 

The fact that HBCD is found in fish indicates that it is also bioavailable. However, the low fish to sediment ratio (below 1) does not agree with the high ratios reported by Sellstrom et al. [29] for pikes from a Swedish River. Pike is a predator at the top of the food chain and the higher fish to sediment ratio in this specie could indicate the biomagnification of this compound through the aquatic trophic chain. 

Mercury (Hg) can occur in a large number of physical and chemical forms with a variety of properties, thus determining complex distribution, bioavailability, and toxicity patterns [1]. The most important chemical forms are elemental Hg (Hg°), ionic Hg (Hg2+ and Hg22+), and alkylmercury compounds. Because of their capability to permeate through biological membranes and to bioaccumulate and to biomagnificate through the trophic chain, alkylmercury compounds are the most toxic mercury species found in the aquatic environment [2]. 

Vighi134 set up a laboratory continuous-flow system to breed a simple trophic chain... 

Vighi, M. 1981. Lead uptake and release in an experimental trophic chain. Ecotoxicol. Environ. Safety 5 177-193. 

The health of the population is closely related to the environmental situation in industrial areas. Heavy metals were the priority contaminators in large industrial centers of Ukraine for a long period of time [1]. They penetrated into the environment inside industrial wastes, and then circulate in trophic chains and reside in tissues of plants, animals, and humans. Our previous analyses showed that soil Zn deficiencies... 

Phytoplankton as test organisms in toxicity bioassays with surfactants Microalgae are the basis of the aquatic trophic chain and at least 30% of the organic carbon planetary primary production is attributed to... 

The relatively modest importance of fish in trophic dynamics is greatly exceeded by their economic importance, and so by the research effort put in by workers from many countries. Further knowledge of the biology of fish is still required. Fish are also suitable subjects for the study of adaptation and evolution. Being a top link in the trophic chain, they can also serve as an indicator of the condition of the whole ecosystem. 

This disproportion between the role of land and ocean ecosystems in food production is explained, primarily, by the fact that agriculture has been intensively developed, whereas in the seas and oceans development has been poor by comparison. Possible ways of increasing ocean bioproductivity have not been considered beyond catching animals at the end of the trophic chains of natural communities of the World Ocean (i.e., fish and whales). Each successive trophic level gains about 0.1% of the share of energy accumulated at a previous level. On land, two levels of organisms (vegetation and herbivores) are used, but in the ocean and in the seas there are up to five levels. The direct use of non-fish species will make it possible to sharply increase the amount of protein obtained from the ocean. 

MBB Marine Biota Block, containing the set of models of energy flows in the trophic chains of the Arctic Basin ecosystem (Krapivin, 1995 Legendre and Legendre, 1998 Legendre and Krapivin, 1992). 

With respect to metal ions, ecological stoichiometry is mnch in its beginnings still (one reason to extend this volnme to that topic as snggestedby one referee), giving jnst sketches of what happens to metals in a trophic chain (ibid, for limnetic systems). Thus, there is no... 

Table 2.11 Biomagnification of elements in simplified trophic chains in freshwater (Franzle and Markert 2002)...

Fig. 2.11 Stoichiometric ratios (C/N vs N/P) in a limnetic trophic chain of four members (alga, water flea, planktivo-rous white fish, perch). The composition of algae (unlike animals, higher plants or bacteria) does thoroughly depend...

Essential elements may even become depleted upward a trophic chain, eventually limiting its length, moreover. 

Thns after the Cambrian explosion in novel trophic chains with now >2 trophic levels the issnes of nntrient transfer and cycling, inclnding that of trace metals, became prominent even now, there are no essential metals which nndergo consistent, step-by-step enrichment within limnetic trophic chains (Franzle and Markert 2002), the only metal to do so from phytoplankton via zooplankton eventnally to piscivorons fishes being niobinm. In addition, the shift from nni- to multicellular top-level consumers implied cell-type... 

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