Primary productivity measurements in the Ross Sea, Antarctica: a regional synthesis
<p>Polar systems are undersampled due to the difficulty of sampling remote and challenging environments; however, these systems are critical components of global biogeochemical cycles. Measurements on primary productivity in specific areas can quantify the input of organic matter to food webs...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-06-01
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| Series: | Earth System Science Data |
| Online Access: | https://essd.copernicus.org/articles/14/2737/2022/essd-14-2737-2022.pdf |
| Summary: | <p>Polar systems are undersampled due to the difficulty of
sampling remote and challenging environments; however, these systems are
critical components of global biogeochemical cycles. Measurements on primary
productivity in specific areas can quantify the input of organic matter to
food webs and so are of critical ecological importance as well. However,
long-term measurements using the same methodology are available only for a
few polar systems. Primary productivity measurements using <span class="inline-formula"><sup>14</sup></span>C-uptake
incubations from the Ross Sea, Antarctica, are synthesized, along with
chlorophyll concentrations at the same depths and locations. A total of 19 independent cruises were completed and 449 stations occupied where
measurements of primary productivity (each with seven depths) were completed.
The incubations used the same basic simulated in situ methodology for all.
Integrated water column productivity for all stations averaged 1.10<span class="inline-formula"> ±</span> 1.20 g C m<span class="inline-formula"><sup>−2</sup></span> d<span class="inline-formula"><sup>−1</sup></span>, and the maximum was 13.1 g C m<span class="inline-formula"><sup>−2</sup></span> d<span class="inline-formula"><sup>−1</sup></span>.
Annual productivity calculated from the means throughout the growing season
equalled 146 g C m<span class="inline-formula"><sup>−2</sup></span> yr<span class="inline-formula"><sup>−1</sup></span>. The mean chlorophyll concentration in
the euphotic zone (the 1 % irradiance level) was 2.85<span class="inline-formula"> ±</span> 2.68 mg m<span class="inline-formula"><sup>−3</sup></span> (maximum observed concentration was 19.1 mg m<span class="inline-formula"><sup>−3</sup></span>). Maximum
photosynthetic rates above the 30 % isolume (normalized to chlorophyll)
averaged 0.98<span class="inline-formula"> ±</span> 0.71 mg C (mg chl)<span class="inline-formula"><sup>−1</sup></span> h<span class="inline-formula"><sup>−1</sup></span>, similar to the
maximum rate found in photosynthesis–irradiance measurements. Productivity
measurements are consistent with the temporal patterns of biomass found
previously, with biomass and productivity peaking in late December; mixed
layers were at a minimum at this time as well. Estimates of plankton
composition also suggest that pre-January productivity was largely driven by
the haptophyte <i>Phaeocystis antarctica</i> and summer productivity by diatoms. The data set (<a href="https://doi.org/10.26008/1912/bco-dmo.863815.2">https://doi.org/10.26008/1912/bco-dmo.863815.2</a>, Smith, 2021) will be
useful for a comparison to other Antarctic regions and provide a basis for
refined bio-optical models of regional primary productivity and
biogeochemical models for the Southern Ocean.</p> |
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| ISSN: | 1866-3508 1866-3516 |