Trait modeling to predict benthic functions and vulnerabilities across black sea seascapes.

Benthic biodiversity is of global significance for the provision of ecosystem services and the mediation of global biogeochemical cycles. The lack of detailed spatial distributions of the functions and vulnerabilities of the benthos critically prevents us from protecting benthic biodiversity and its functioning in the context of increasing human perturbations and climate change. Here, we propose a multidisciplinary approach to bridging in situ benthic data to the maps of macrobenthic functions and vulnerabilities at the scale of the northwestern shelf of the Black Sea. Our findings show that oxygen availability is a key driver of the functional trait composition of macrozoobenthic communities. Shallower well-oxygenated areas support high biomixing and bioirrigation on muddier-sandier substrata and high biodeposition on coarser substrata associated with mussel reef communities. In contrast, at depleted oxygen areas at the edge of the shelf, macrobenthic communities are functionally impoverished with only a combination of a few typical opportunistic traits, and those communities have a negligible impact on ecosystem functions. Mapping of vulnerabilities and functions of benthic communities can support marine management strategies aligned with the United Nations Sustainable Development Goal 14: Life Below Water.