Cryptic foraminiferal diversity and its role in colonization of new substrates

Lead Author Dmitrii, Mikhailov
Institution Contact Saint Petersburg State University, Russian Federation
Co-Authors Sergei Korsun, Saint Petersburg State University, Russian Federation
Theme Theme 1: Vulnerability of Arctic Environments
Session Name 1.1 Climate Change and Environmental Management in the Arctic
Presentation Type Poster
Abstract text Climate changes affect biotic assemblages. The response of assemblage to induced environmental stress includes a shift in the community structure, provided by transport of recruits from other populations. Less obvious but also important way of such shift is the in situ growth of dormant individuals, activated when the new environmental conditions suite them.
Foraminifera are meiobenthic protists, diverse and abundant all over the world ocean, including Arctic. They are well known for their intricate shell. Due to high fossilization potential of this shell, Foraminifera are the traditional tool for paleoecological reconstructions, affording, for example, extrapolation of past climate change events into the modern communities, and vice versa. To improve our attempts in paleoreconstractions, we still need a deeper insight in biology and ecology of modern foraminiferal species.
In our study we investigate foraminiferal community response to environmental changes – transport, recruiting (i.e. colonization process) and dormancy. In the present state of knowledge, these processes are tightly connected in the foraminiferal life history. Dormant juveniles theoretically may be transported by water currents, and then deposited in sediment, where they stay inactive for years. They begin to grow, if environmental conditions become suitable for them. Thus, the dormant foraminiferal juveniles (“propagules”) form the pool in bottom sediments, that ensures a rapid response of the foraminiferal community to the environmental stress.
We deployed sediment traps, which accumulated from plankton not only adult benthic foraminifera (as was expected), but also precipitating “propagules” of benthic foraminifera. Simultaneously we found the bank of “propagules” of the same species, in the adjacent bottom sediment. So our experiments have proved the pelagic dispersal of benthic foraminiferal propagules. These results demonstrate how foraminiferal communities may response to future environment changes.