Document Type

Article

Department/Program

Virginia Institute of Marine Science

Publication Date

2015

Journal

BIOGEOSCIENCES

Volume

12

Issue

11

First Page

3567

Last Page

3577

Abstract

A meta-analysis of photosynthesis-irradiance measurements was completed using data from the Ross Sea, Antarctica, using a total of 417 independent measurements. P-m(B), the maximum, chlorophyll-specific, irradiancesaturated rate of photosynthesis, averaged 1.1 +/- 0.06 mu gC (mu g Chl)(-1) h(-1). Light-limited, chlorophyll-specific photosynthetic rates (alpha(B)) averaged 0.030 +/- 0.023 mu gC (mu g Chl)(-1) h(-1) (mu mol quanta m(-2) s(-1))(-1). Significant variations in P-m(B) and alpha(B) were found as a function of season, with spring maximum photosynthetic rates being 60% greater than those in summer. Similarly, alpha values were 48% greater in spring. There was no detectable effect of sampling location on the photosynthetic parameters, and temperature and macronutrient (NO3) concentrations also did not have an influence. However, irradiance and carbon dioxide concentrations, when altered under controlled conditions, exerted significant influences on photosynthetic parameters. Specifically, reduced irradiance resulted in significantly decreased P-m(B) and increased alpha(B) values, and increased CO2 concentrations resulted in significantly increased P-m(B) and alpha(B) values. Comparison of photosynthetic parameters derived at stations where iron concentrations were above and below 0.1nM indicated that reduced iron levels were associated with significantly increased P-m(B) values, confirming the importance of iron within the photosynthetic process. No significant difference was detected between stations dominated by diatoms and those dominated by the haptophyte Phaeocystis antarctica. The meta-analysis confirms the photosynthetic rates predicted from global analyses that are based solely on temperature and irradiance availability, but suggests that, for more accurate predictions of productivity in polar systems, a more detailed model that includes temporal effects of photosynthetic parameters will be required.

DOI

10.5194/bg-12-3567-2015

Keywords

SOUTHERN-OCEAN PHYTOPLANKTON; MARINE-PHYTOPLANKTON; FRAGILARIOPSIS-CYLINDRUS; PHAEOCYSTIS-ANTARCTICA; COMMUNITY STRUCTURE; IRON; OCEANOGRAPHY; TEMPERATURE; GROWTH; LIGHT

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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