We have a new open access paper published in Scientific Reports that discusses differences in estimates of community-level productivity (photosynthesis vs. respiration) in tide pools. We carried out this work in southeastern Alaska on an intertidal rocky shore, where individual tide pools that become isolated from the ocean at low tide can serve as little contained communities. We estimated net production by measuring dissolved oxygen change within the pools under normal daylight conditions, during night time conditions, and under artificial dark conditions during the day. To create artificial dark conditions, we covered the tidepool with an opaque black tarp for at least 30 minutes, and then made oxygen measurements after that dark incubation.
We found that our estimates of net productivity in the community are very much affected by the dark incubation method used (plastic tarp during the day versus middle of the night), and that this affect appears to be tied to initial oxygen levels and water temperature, both of which change quite a bit during the course of the day. As a result, methods used to estimate community productivity should be approached with caution to make sure that you’re getting a reasonable measurement.
The paper can be accessed for free here: https://doi.org/10.1038/s41598-021-04685-8
Bracken, M.E.S., L.P. Miller, S.E. Mastroni, S.M. Lira and C.J.B. Sorte (2022) Accounting for variation in temperature and oxygen availability when quantifying marine ecosystem metabolism. Scientific Reports 12, 825