Data from: Marine latitudinal diversity gradients, niche conservatism, and out of the tropics and Arctic: climatic sensitivity of small organisms

Aim The latitudinal diversity gradient (LDG) is a consequence of
evolutionary and ecological mechanisms acting over long history, and thus
is best investigated with organisms that have rich fossil records.
However, combined neontological-paleontological investigations are mostly
limited to large, shelled invertebrates, which keeps our mechanistic
understanding of LDGs in its infancy. This paper aims to describe the
modern meiobenthic ostracod LDG and to explore the possible controlling
factors and the evolutionary mechanisms of this large-scale biodiversity
pattern. Location Present-day Western North Atlantic Taxon Ostracoda
Methods We compiled census data from ostracods living in shallow marine
environments of the western North Atlantic Ocean. Using these data, we
documented the marine LDG with multiple metrics of alpha, beta (nestedness
and turnover), and gamma diversity, and we tested whether macroecological
patterns could be governed by different environmental factors, including
temperature, salinity, dissolved oxygen, pH and primary productivity. We
also explored the geologic age distribution of ostracod genera to
investigate the evolutionary mechanisms underpinning the LDG. Results Our
results show that temperature and climatic niche conservatism are
important in setting LDGs of these small, poorly-dispersing organisms. We
also found evidence for some dispersal-driven spatial dynamics in the
ostracod LDG. Compared to patterns observed in marine bivalves, however,
dispersal dynamics were weaker and they were bi-directional, rather than
following the “out-of-the-tropics” model. Main Conclusions Our detailed
analyses revealed that meiobenthic organisms, which comprise two-thirds of
marine diversity, do not always follow the same rules as larger,
better-studied organisms. Our findings suggest that the under-studied
majority of biodiversity may be more sensitive to climate than are
well-studied, large organisms. This implies that the impacts of ongoing
Anthropocene climatic change on marine ecosystems may be much more serious
than presently thought.