Members of C-CAN Listserv discuss microbial impacts relative to OA

A C-CAN listserv discussion on relationship between OA and microbial impacts, HABs

 C-CAN steering committee member Ian Jefferds began the discussion, noting the importance of considering microbial impacts to marine carbonate chemistry in the discussion of OA.  He introduced the group to  microbiologist Linda Rhodes, NOAA, who serves on the Whidbey Island Marine Resources Committee.

Linda chimed in:  Our recent work in Puget Sound indicates a link between changes in microbial abundances and pH, & this is probably a result of seasonal fluctuations in primary & heterotrophic production. This could mean that microbes play a larger role in pH changes in Puget Sound than open coastal areas.  (A caveat: our work is not directly connected to OA because OA has a definition limited to pH changes asociated with increased CO2 uptake by oceans.)  While there has been plenty of attention paid to the effects of OA on microbial communities (& downstream effects on food webs), less attention has been paid to the potential effect of microbes on OA, either potentiating or ameliorating OA’s impacts.  Most of the latter work seems to focus on engineering CO2 sinks, e.g., fertilizing phytoplankton blooms, rather than determining the ecosystem role of microbes in OA.

We are in the throes of putting together the final report for the multi-trophic level assessment of Puget Sound (Bellingham to Olympia plus Hood Canal) we conducted last year, & it seems that a suite of measurements (water chemistry & physical features; bacterial, jellyfish & forage fish abundance) may be useful for evaluating & monitoring ecosystem status.  While this doesn’t feed directly into OA research, we think the multi-level approach encompassing both abiotic & biotic factors, would be a useful conceptual framework.
Dave Hutchins added:  C-CAN folks — Here is another paper we published a couple of years ago on microbial responses to acidification, it has a somewhat different perspective from the Joint et al. paper Scott sent around.  I think it is a good idea to open some discussion about microbes and OA as part of C-CAN, as I showed in the last meeting, effects of OA on harmful algal bloom toxins could have significant impacts on shellfish production, aside from any more indirect effects of changes in planktonic food quality or bacterially-mediated biogeochemical processes.

David Hutchins
Professor of Marine Environmental Biology
Department of Biological Sciences
University of Southern California

Dave’s paper:  Nutrient Cycles and Marine Microbes in a CO2 Enriched Ocean