SP5 Effects of environmental dynamics and disturbances on macrozoobenthos

• Applicants: Professorin Dr. Gabriele Gerlach; Dr. Sven Rohde
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 379417748

Progressive environmental changes have a significant impact on global biodiversity. The adaptive capacity of organisms through endogenous mutations cannot keep pace with the speed of change. However, recent studies suggest that shifts in dietary patterns and variability in the microbiome can strongly influence the resistance of organisms. The main goal of this project is to assess the existing resistance of marine invertebrates populations to variable environmental parameters and to understand the mechanisms that contribute to potential resilience. This is accordance with Dynacom's overarching objective O2 which aims to extend trait-based characterization of spatial communities to dynamic landscapes that are subject to strong stochastic disturbances. We will compare naturally more disturbed macrozoobenthos (MZB) communities in the eulittoral, which are regularly exposed to strong tidal fluctuations (desiccation, salinity and temperature stress), with those in the sublittoral which lack such extreme conditions. We assume that -depending on mobility- organisms in the eulittoral being exposed to a wider range of environmental conditions exhibit greater resilience to these variations than conspecifics from the deeper sublittoral habitat, where conditions are more stable. The project consists of several work packages: 1) To evaluate how mobility and prey composition affect MZB communities, we will monitor MZB composition in relation to the present algal/bacterial communities in spring and summer at different depths. To understand the influence of different mobility of species, we will further focus on two polychaetes, the sand mason worm Lanice conchilega, which is not mobile as an adult, and the mobile ragworm Hediste diversicolor. 2) To study the effect of a stochastic disturbance, we will expose representatives of these species from different depths in mesocosm experiments to a temperature pulse (heat wave) and monitor their response such as survival, but also their food intake (isotope analysis, fatty acids) and physiological stress parameters (oxygen consumption, antioxidative stress) and expression of stress related genes. 3) To investigate the influence of the microbiome on resistance and resilience, the digestive tract microbiome community of the two polychaete species from eulittoral and sublittoral habitats will be analyzed by sequencing the 16s RNA gene locus and compared with that of the algae/bacteria (SP4) to assess seasonal differences in the diet on the consumer microbiome. 4) L. conchilega specimens from the sublittoral will be inoculated with microbiomes from eulittoral specimens to determine whether resistance to temperature stress will increase in inoculated specimens.

• DFG Programme: Research Units
• Subproject of: FOR 2716: Spatial community ecology in highly dynamic landscapes: from island biogeography to metaecosystems [DynaCom]
• Co-Investigators: Professorin Dr. Ingrid Kröncke, Ph.D.; Professor Dr. Peter Schupp