2009/11/04 by Ulrike Braeckman, Pieter Provoost, Britta Gribsholt +5 · 1 citation
Earth and Planetary Sciences · Environmental Science · #Marine Biology and Ecology Research #Marine Bivalve and Aquaculture Studies #Marine and fisheries research #Bioturbation #Benthic zone #Microcosm #Biogeochemical cycle #Ecology #Oceanography #Ecosystem #Environmental science #Spring bloom #Polychaete #Biogeochemistry #Fauna #Phytoplankton #Sediment #Biology #Nutrient #Geology
paper · pdf · doi:10.3354/meps08336
openalex publication_date 2009/11/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
The importance of different functional traits of macrobenthos in benthic processes of the Southern Bight of the North Sea was investigated to estimate the effects of density declines and species loss on benthic ecosystem functioning. Two laboratory experiments were performed: before (winter, temperature = 10°C) and after (summer, temperature = 18°C) sedimentation of the spring phytoplankton bloom. Single species treatments of key species (<i>Abra alba</i>, <i>Lanice conchilega</i> and <i>Nephtys</i> sp.) with different functional traits were added to microcosms at 3 density levels (natural, lower, lowest) to account for possible density declines. Sediment–water exchanges of oxygen and nutrients, denitrification and bioturbation were measured. In absence of fauna, benthic mineralisation in the summer experiment was 2.0 times higher than in winter. Fauna stimulated microbial respiration more in summer (up to 100% in <i>L. conchilega</i> treatments) than in winter (negligible fauna effect). As chlorophyll <i>a</i> concentrations were similar in both seasons, the stronger fluxes in summer must be explained by a higher macrobenthic activity owing to the elevated temperature and better condition of the animals. Stimulation of mineralisation by the 3 species in the microcosms was different, and behaviour-related. Owing to its irrigation activity, the tube dweller <i>L. conchilega</i> had more pronounced influences on benthic respiration, nutrient release and denitrification than did the biodiffusers, <i>A. alba</i> and <i>Nephtys</i> sp. <i>A. alba</i> appeared to be a more effective bioturbator than <i>Nephtys</i> sp. Processes such as benthic respiration, nutrient fluxes, denitrification and bioturbation seem to be related to animal densities and therefore decreases in densities can possibly have implications for ecosystem functioning.