12R
5 Spatial and Temporal DistributIOn Patterns
microbial degradation and mineralization of the biomass caused an additional
oxygen consumption.
5.2.4
Conclusions
The investigations at the transect on the Swinnplate aimed at bringing more light
into interactions between biogeochemical parameters and the distribution patterns
of macrobenthos, especially in relation to enrichments with organic matter (here in
the form of biodeposits). Similar distributions were found as those already described by Pearson & Rosenberg (1978), Rhoads et al. (1978) and were also reported by Hertweck (1992), Dittmann (1987) and Kroncke (1996) for the Wadden
Sea. The different succession models, giving more weight to either organic matter
or sediment properties, do not really exclude or contradict, but can even support
each other. As the results of the transect study show, mud- and POCconcentrations of the sediment were correlated and can both influence or regulate
the distribution of macrofauna. Furthermore, parameters, which change simultaneously with variations of POC- and mud-contents (and partly being dependent on
them), like oxygen- and sulphide-concentrations, redox-potentials and pH-values,
cannot be ignored. In ecological systems, under natural conditions, the interaction
of several environmental factors is usually decisive for the development of patterns
and processes (Snelgrove & Butman 1994). The investigations on the Swinnplate
had the difficulty that the location and density of the mussel bed changed from
year to year. Thus, no continuous gradient of biodeposits was present on the studied transect. Future studies should check the interactions between POC, grain size
and benthos under controlled laboratory conditions or in mesocosm experiments.
Sulphide-and oxygen-profiles should be measured in these experiments as well.
The specific investigation of the quality of organic matter should also be in the
centre of attention, since the results showed, that quantitative determinations of
bulk POC are not sufficient to explain its role as an environmental factor.
Acknowledgements
This chapter is based on the work and the data provided by several sub-projects of
ELA WAT carried out by B. Albers, A. Bartholoma, B. Behrends, C. Bergfeld, M.
E. Bottcher, E. Boysen-Ennen, P. Brocks, H.-J. Brumsack, M. T. Delafontaine, B.
W. Flemming, G. Hertweck, A. Hild, T. Hopner, K. Knauth-Kohler, I. Kroncke,
W. E. Krumbein, 1. Langner, T. Leu, G. Liebezeit, B. Oelschlager, D. Rohjans, 1.
Rullkotter, T. Stoeck, M. Tiirkay, M. ViII brandt and F. Wolf. Their studies have
been published as cited in the text and further unpublished data were kindly provided. We wish to thank two reviewers for their valuable and helpful comments on
the manuscript. The project was funded by the German Bundesministerium fUr
Bildung, Wissenschaft, Forschung und Technologie (BMBF) under grant number
03FO 112 A and B. The responsibility for the contents of the publication rests with
the authors.
5 Spatial and Temporal DistributIOn Patterns
microbial degradation and mineralization of the biomass caused an additional
oxygen consumption.
5.2.4
Conclusions
The investigations at the transect on the Swinnplate aimed at bringing more light
into interactions between biogeochemical parameters and the distribution patterns
of macrobenthos, especially in relation to enrichments with organic matter (here in
the form of biodeposits). Similar distributions were found as those already described by Pearson & Rosenberg (1978), Rhoads et al. (1978) and were also reported by Hertweck (1992), Dittmann (1987) and Kroncke (1996) for the Wadden
Sea. The different succession models, giving more weight to either organic matter
or sediment properties, do not really exclude or contradict, but can even support
each other. As the results of the transect study show, mud- and POCconcentrations of the sediment were correlated and can both influence or regulate
the distribution of macrofauna. Furthermore, parameters, which change simultaneously with variations of POC- and mud-contents (and partly being dependent on
them), like oxygen- and sulphide-concentrations, redox-potentials and pH-values,
cannot be ignored. In ecological systems, under natural conditions, the interaction
of several environmental factors is usually decisive for the development of patterns
and processes (Snelgrove & Butman 1994). The investigations on the Swinnplate
had the difficulty that the location and density of the mussel bed changed from
year to year. Thus, no continuous gradient of biodeposits was present on the studied transect. Future studies should check the interactions between POC, grain size
and benthos under controlled laboratory conditions or in mesocosm experiments.
Sulphide-and oxygen-profiles should be measured in these experiments as well.
The specific investigation of the quality of organic matter should also be in the
centre of attention, since the results showed, that quantitative determinations of
bulk POC are not sufficient to explain its role as an environmental factor.
Acknowledgements
This chapter is based on the work and the data provided by several sub-projects of
ELA WAT carried out by B. Albers, A. Bartholoma, B. Behrends, C. Bergfeld, M.
E. Bottcher, E. Boysen-Ennen, P. Brocks, H.-J. Brumsack, M. T. Delafontaine, B.
W. Flemming, G. Hertweck, A. Hild, T. Hopner, K. Knauth-Kohler, I. Kroncke,
W. E. Krumbein, 1. Langner, T. Leu, G. Liebezeit, B. Oelschlager, D. Rohjans, 1.
Rullkotter, T. Stoeck, M. Tiirkay, M. ViII brandt and F. Wolf. Their studies have
been published as cited in the text and further unpublished data were kindly provided. We wish to thank two reviewers for their valuable and helpful comments on
the manuscript. The project was funded by the German Bundesministerium fUr
Bildung, Wissenschaft, Forschung und Technologie (BMBF) under grant number
03FO 112 A and B. The responsibility for the contents of the publication rests with
the authors.