Sundback, K. Marine Botany, Goteborg University,
Brotas, V. Inst. Oceanografia, Universade de Lisboa,
Dalsgaard, T. National Environmental Research Institute,
Nielsen, L. P.. University of Aarhus, Microbial Ecology,
Underwood, . Biological and Chemical Sciences; John Tabor Laboratories,
Viaroli, . Institute of Ecology,

Shallow-water sediments may play a significant role for the retention and removal of the anthropogenically increased nitrogen load in coastal areas. One aim of the EU-project Nitrogen Cycling in Estuaries is to study the role of benthic primary producers in nitrogen turnover in some European estuaries representing different regimes of temperature, nutrient status and tidal amplitude. Results from areas dominated by microphytobenthos are presented. To describe the variation of N flux over an annual cycle, sediment-water oxygen and nutrient exchange, primary production, denitrification, as well as algal biomass were measured using intercalibrated methods on 18 sites (24 stations) representing shallow coastal areas along the coasts of Italy, Portugal, United Kingdom, Denmark and Sweden. Despite large variations in environmental factors, the mean annual chlorophyll a content of the sediment varied only by a factor of 2. However, oxygen flux measurements showed large differences between the sites in the degree of benthic autotrophy. Although the magnitude of fluxes varied regionally by orders of magnitude, a significant influence of microphytobenthic activity on nutrient fluxes was observed at all study sites. The balance between microalgal N-retention and N-removal by denitrification is compared and discussed.
Day: Friday, Feb. 5
Time: 08:30 - 08:45am
Location: Eldorado Hotel
Code: SS46FR0830E