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Primary productivity and microbially activated transport of elements (C, P, Fe) in tide-influenced deposits

Objective

The objectives of PRO-MAT are :

1. To examine the microstructure, bio-diversity and seasonality of mat and biofilm communities from cohesive, non-cohesive and mixed sediment substrata.

2. To assess primary production by these assemblages, examine the reliability of existing models and determine the generic significance of extracellular polymeric substances (EPS) as a component of the carbon cycle within sediments and in relation to sediment stability.

3. To study the biogeochemical cycles of carbon, iron and phosphorus with natural and laboratory model systems and examine the interaction between primary productivity and inorganic carbon, iron and phosphorus.


Natural sediment deposits are colonised by assemblages of microbial organisms forming biofilms or mats at the sediment surface. These assemblages mediate transport processes between the sediment and the overlying air/water and also occupy the transition zone between land and sea. They are the first communities to be influenced by changes in global sea level and have a fundamental role in ecosystem dynamics. Moreover, phototrophic microbial assemblages serve as a biogeochemical engine providing a site for carbon and nitrogen fixation. Primary productivity can be intense in the mats or biofilms easily equating to terrestrial ecosystems. The functioning of these marginal systems is therefore central to the biogeochemistry and ecology of shallow coastal waters. This interdisciplinary study considers aspects of the biogeochemistry of these assemblages, centering on the cycling of elements, ecophysiology, diversity, structure, physical influence and their importance for the carbon budget of coastal systems.
Comparisons will be made between three intertidal sites around Europe which differ in sediment composition, tidal influence and assemblage diversity and microstructure. Transient biofilms (Tay Estuary & East Sands, Scotland), seasonal cyanobacterial/diatom mats (cocksdorp, Texel, Netherlands) and perennial mats (mellum, Germany) will be considered. Assemblage structure and diversity will be investigated using various techniques including light and electron microscopy. Carbon fixation will be examined by analysis of primary productivity using non-destructive in situ microsensors. The links between the transport of Fe and P,the form in which these elements occur and interactions with primary productivity will be examined.
The project will help characterise the diversity and structure of the microbial assemblages that form an important global site for biogeochemical cycling and provide data toward the interpretation of global change and factors such as increasing marine eutrophication (P, Fe), tidal level elevation and temperature increase and the implication of these variables for carbon turnover.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

University of St Andrews
Address
Gatty Marine Laboratory
St Andrews
United Kingdom

Participants (2)

UNIVERSITY OF OLDENBURG
Germany
Address
Ammerlaender Heerstrasse 114-118
26111 Oldenburg
Universiteit van Amsterdam
Netherlands
Address
127,Nieuwe Achtergracht
1018 WS Amsterdam