Physicochemical and photosynthetic characteristics of water samples obtained during a CCGS Amundsen cruise in 2008, supplement to: Palmer, Molly A; Arrigo, Kevin R; Mundy, Christopher John; Ehn, Jens K; Gosselin, Michel; Barber, David G; Martin, Johannie; Alou, Eva; Roy, Suzanne; Tremblay, Jean-Éric (2011): Spatial and temporal variation of photosynthetic parameters in natural phytoplankton assemblages in the Beaufort Sea, Canadian Arctic. Polar Biology, 34(12), 1915-1928
During summer 2008, as part of the Circumpolar Flaw Lead system study, we measured phytoplankton photosynthetic parameters to understand regional patterns in primary productivity, including the degree and timescale of photoacclimation and how variability in environmental conditions influences this r...
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
PANGAEA - Data Publisher for Earth & Environmental Science
2011
|
| Subjects: | |
| Online Access: | https://dx.doi.org/10.1594/pangaea.817840 https://doi.pangaea.de/10.1594/PANGAEA.817840 |
| Summary: | During summer 2008, as part of the Circumpolar Flaw Lead system study, we measured phytoplankton photosynthetic parameters to understand regional patterns in primary productivity, including the degree and timescale of photoacclimation and how variability in environmental conditions influences this response. Photosynthesis-irradiance measurements were taken at 15 sites primarily from the depth of the subsurface chlorophyll a (Chl a) maximum (SCM) within the Beaufort Sea flaw lead polynya. The physiological response of phytoplankton to a range of light levels was used to assess maximum rates of carbon (C) fixation (P*m), photosynthetic efficiency (alpha*), photoacclimation (Ek), and photoinhibition (beta*). SCM samples taken along a transect from under ice into open water exhibited a >3-fold increase in alpha* and P*m, showing these parameters can vary substantially over relatively small spatial scales, primarily in response to changes in the ambient light field. Algae were able to maintain relatively high rates of C fixation despite low light at the SCM, particularly in the large (>5 µm) size fraction at open water sites. This may substantially impact biogenic C drawdown if species composition shifts in response to future climate change. Our results suggest that phytoplankton in this region are well acclimated to existing environmental conditions, including sea ice cover, low light, and nutrient pulses. Furthermore, this photoacclimatory response can be rapid and keep pace with a developing SCM, as phytoplankton maintain photosynthetic rates and efficiencies in a narrow ''shade-acclimated'' range. : Data extracted in the frame of a joint ICSTI/PANGAEA IPY effort, see http://doi.pangaea.de/10.1594/PANGAEA.150150 |
|---|