Abundance, biomass and species richness of macrozoobenthos along an intertidal elevation gradient

Ecology aims to comprehend species distribution and its interaction with environmental factors, from global to local scales. While global environmental changes affect marine biodiversity, understanding the drivers at smaller scales remains crucial. Tidal flats can be found on most of the world’s coastlines and are particularly vulnerable to anthropogenic disturbances. They are important transient ecosystems between terrestrial and marine ecosystems and their biodiversity provides important ecosystem services. Owing to this unique position at the terrestrial-marine transition, strong environmental gradients of elevation, sediment composition and food availability prevail. 

The data set contains information on macrozoobenthos abundance, biomass and community composition and abiotic and biotic environmental factors at a regional and local level at back barrier tidal flats of three East-Frisian islands in Germany. As environmental data elevation, mud content in the sediment, total organic carbon (TOC), porewater nutrients and Chl a are included.

Methods
We sampled a total of 9 transects with 27 sampling stations, i.e., three transects perpendicular to the island coast at each island comprised of three sampling stations each. Each sampling station was marked with a DGPS to estimate the elevation of the study plot. To cover the spatial and the temporal changes in the macrozoobenthos community, sampling took place once in spring and once in summer of 2019. At each of the sampling stations, we took three subsamples for macrozoobenthos with hand corers that had a diameter of 10 cm (0.0078 m2) and a height of 20 cm, which were driven into the sediment at low tide. Samples were washed over a 500 µm sieve and fixated using 4%- buffered-formaldehyde solution.

In the lab, samples were stained with rose bengal and identified to species level (or the lowest possible taxonomic unit). After taxonomic identification, abundances of each species and wet biomass were determined.

Additionally, sediment composition, Chl a, TOC, pore water nutrients (DIN, RDP) and elevation were measured at the same date and sampling sites.