Modelling benthic nitrogen cycling in temperate coastal ecosystems
This chapter describes the ecological processes of the inshore regions of the continental shelf in temperate latitudes. Inmany of these areas, particularly those of the North Atlantic shelf, the high turbulence due to tides and winds ensures good vertical homogeneity of a rather shallow water column...
| Main Authors: | , |
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| Format: | Conference Object |
| Language: | English |
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1988
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| Subjects: | |
| Online Access: | http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/58197 https://dipot.ulb.ac.be/dspace/bitstream/2013/58197/4/c6992836-b2a6-49b8-8451-cd9ccfec72a6.txt |
| Summary: | This chapter describes the ecological processes of the inshore regions of the continental shelf in temperate latitudes. Inmany of these areas, particularly those of the North Atlantic shelf, the high turbulence due to tides and winds ensures good vertical homogeneity of a rather shallow water column. Under such circumstances, sediments playa prominent part in the overall working of the ecosystems, and are in close interaction with the planktonic phase (Paasche; Blackburn, this volume). Besides being the starting point of the benthic trophic chain, of considerable economical importance in coastal regions, sediments play two key roles with respect to the plankton system: 1. They act as regenerators of mineral nutrients for the water column. Direct comparison between benthic nitrogen release and planktonic primary production shows that sediments often supply 30-70% of nitrogen requirements by phytoplankton (Table 14.1). 2. Sediments are often the only site in coastal marine ecosystems where anaerobic conditions exist. They are therefore the site of denitrification, a process which can result in the elimination of up to 25% of nitrogen mineralized in the benthos (Table 14.1). In shallow systems, sediments constitute by far the most important reservoir of nitrogen. Owing to the buffering effect of this large stock, benthic nutrient regeneration is more steady than most water column remineralization processes, and is also more constant than exchange through thermoclines, which are often of intermittent nature. We will see that the seasonal variations of planktonic processesin temperate coastal ecosystemsare largely dependent on the behaviour of the large pools of organic material deposited in the sediments. For understanding the role of benthos in nutrient cycling at the ecosystem level, and for relating this role to the basic microbiological and physicochemical processes occurring in the sedimentary environment, mathematical modelling can be a very powerful tool. A model can be defined as a simplified representation ... |
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