|Effects of spring phytoplankton bloom deposition on seasonal dynamics and vertical distribution of microbial eukaryotes in a silty, metal-contaminated sediment in the Southern North Sea|
Pede, A.; Gillan, D.C.; Billon, G.; Lesven, L.; Leermakers, M.; Baeyens, W.; Verstraete, T.; Vyverman, W.; Sabbe, K. (2012). Effects of spring phytoplankton bloom deposition on seasonal dynamics and vertical distribution of microbial eukaryotes in a silty, metal-contaminated sediment in the Southern North Sea, in: Pede, A. Diversity and dynamics of protist communities in subtidal North Sea sediments in relation to metal pollution and algal bloom deposition. pp. 51-77
In: Pede, A. (2012). Diversity and dynamics of protist communities in subtidal North Sea sediments in relation to metal pollution and algal bloom deposition. PhD Thesis. Universiteit Gent; Vakgroep Biologie, Onderzoeksgroep Protistologie en Aquatische Ecologie: Gent. 200 pp., more
|Authors|| || Top |
- Pede, A., more
- Gillan, D.C., more
- Billon, G.
- Lesven, L., editor
- Leermakers, M., more
Microbial communities from a subtidal, silty, metal-contaminated sediment in the Belgian Coastal Zone, sampled between February and July 2008, were studied using denaturant gradient gel electrophoresis (DGGE). Seasonal and vertical dynamics in the structure of the microeukaryotic community, and Protozoa in particular, were studied in relation to the sedimentation of the spring phytoplankton bloom and linked to variation in the biogeochemical environment, including trace metal dynamics, as previous research had demonstrated that accumulated metals in sediments are released upon bloom sedimentation and degradation (Gao, et al., 2009). Stramenopila (mainly diatoms) were the dominant group in the sediments, followed by Alveolata (ciliates and dinophytes) and Rhizaria (cercozoans, acanthareans and foraminiferans). Sedimentation of the bloom was reflected in increased levels of chlorophyll a and higher abundances of diatoms in the upper sediment layers, and resulted in higher bacterial biomass. Microeukaryote and protozoan community composition changed from February to July, with especially May and July being distinct. Increased microbial mineralization caused pronounced changes in the redox environment and the bioavailable metal concentrations in the sediment, which correlated with the observed seasonal and vertical variation patterns in community structure. Eh and pH were the dominant factors structuring the communities, but trace metals as well had a significant, independent impact on microbial community structure. While no negative effect could be found between the metals and microeukaryotic and protozoan diversity, some taxa, such as a dinoflagellate, appeared to be strongly affected by metal concentrations, while other groups (e.g. ciliates) appeared to be unaffected by higher metal concentrations.