MEPS 579:19-36 (2017)  -  DOI: https://doi.org/10.3354/meps12236

ABSTRACT: Ongoing climate change is causing rapid changes in biodiversity and has ecological impacts on coastal marine systems. Predicting scenarios of how these pressures will affect bioturbation, a process vital to marine communities and human well-being, has become an important task. A first step is a better understanding of the interaction between macrofauna and the surrounding environment. Here, bioturbation (local and non-local sediment mixing) was surveyed using a high-resolution depth distribution of macrobenthos in the southwestern Baltic Sea, which is characterized by different sediment types and faunal communities. The distribution of local and non-local mixing with increasing non-local transports from west to east was explained by comparing vertical chlorophyll profiles and organisms’ depth distributions. The main bioturbators were identified based on chlorophyll profiles and community bioturbation potential (BP_c) and by categorizing the main species into functional groups. Diastylis rathkei is most important for local sediment mixing, and bivalves, e.g. Arctica islandica and Limecola balthica, together with polychaetes, e.g. Nephtys hombergii and Scoloplos armiger, are most important for non-local transports. Significant correlations between modeled local and non-local mixing intensities and calculated BP_c (105-1298 m^-2) indicate that BP_c is a suitable bioturbation indicator; however, it does not provide information on the different modes of mixing. Some species categorized as biodiffusors in the literature were found to cause non-local mixing according to their feeding behavior (e.g. L. balthica), size (e.g. Abra alba) or biomass (e.g. A. islandica).

KEY WORDS:Bioturbation · Macrozoobenthos · Local and non-local transport · Bioturbation potential · Main bioturbator · Functional groups