Dimethylsulfoniopropionate in a salt marsh estuary: correlation to tidal cycle and phytoplankton assemblage composition

• Published in: Marine ecology. Progress series (Halstenbek) 2005-03, Vol.289, p.13-25
• Main Authors: Kulkarni, Nitin R., White, David L., Lewitus, Alan J., Tymowski, Raphael G., Yoch, Duane C.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Biomass; Brackish; Coastal water; Creeks; Diatoms; Estuaries; Freshwater; Fundamental and applied biological sciences. Psychology; Inlets; Marine; Ocean tides; Phytoplankton; Pigments; Salt marshes; Sea water ecosystems; Synecology
• ISSN: 0171-8630; 1616-1599
• DOI: 10.3354/meps289013

Salt marsh estuaries emit high levels of dimethylsulfide (DMS), yet little is known about the contribution of tidal creeks, which are rich in phytoplankton that can potentially produce dimethylsulfoniopropionate (DMSP). Quantitative data is presented on the relationship between phytoplankton assemblage structure during tidal cycles in North Inlet, a high-salinity salt marsh estuary near Georgetown, South Carolina. While there was little or no correlation between chlorophylla(chla) and phytoplankton DMSP (DMSPp) in tidal-creek waters, the DMSPp:chlaratio showed a strong correlation with tidal stage, being highest at high slack tide and lowest at low slack tide. Phytoplankton assemblage structure determined from HPLC pigment profiles and CHEMTAX analysis (a matrix factorization program to derive taxonomic composition from photopigment ratios) showed that DMSP-rich taxa were highly correlated with the high DMSP:chlavalues which occurred at high tide. These were haptophytes, dinoflagellates, cyanobacteria and cryptophytes. Diatoms had a lower correlation coefficient but, because they represented almost 40% of the algal biomass during the tidal cycle, this group could be a significant contributor of DMSPp at high tide. Chlorophytes, prasinophytes, and some chrysophytes showed a strong negative correlation coefficient (r) with the DMSPp:chlapeak. We conclude that the increase in the DMSPp:chlaratio at high tide is due to an increased contribution of DMSP-rich phytoplankton taxa that enter the creeks from coastal waters during flood tide, and low values resulted from low DMSP-containing resuspended benthic microalgae, advected from the adjacent salt marsh into the tidal creeks during ebb tide. The data indicate a strong tidal effect on DMSP concentration that is a function of change in phytoplankton assemblage structure.