Seasonal changes in seawater calcium and alkalinity in the Sargasso Sea and across the Bermuda carbonate platform
Ocean acidification may shift coral reefs from a state of net ecosystem calcification (+NEC) to net ecosystem dissolution (–NEC). Changes in NEC are typically inferred from either measured or calculated total alkalinity (TA) or the dissolved calcium (Ca) to salinity ratio relative to a reference val...
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2022
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ftsouthampton:oai:eprints.soton.ac.uk:453071 2023-07-30T04:06:06+02:00 Seasonal changes in seawater calcium and alkalinity in the Sargasso Sea and across the Bermuda carbonate platform Griffin, Alyssa J. Anderson, Zachary Ballard, John Bates, Nicholas R. Garley, Rebecca Johnson, Rod Martz, Todd Pacheco, Fernando Takeshita, Yuichiro Andersson, Andreas J. 2022-01-20 https://eprints.soton.ac.uk/453071/ English eng Griffin, Alyssa J., Anderson, Zachary, Ballard, John, Bates, Nicholas R., Garley, Rebecca, Johnson, Rod, Martz, Todd, Pacheco, Fernando, Takeshita, Yuichiro and Andersson, Andreas J. (2022) Seasonal changes in seawater calcium and alkalinity in the Sargasso Sea and across the Bermuda carbonate platform. Marine Chemistry, 238, 104064, [104064]. (doi:10.1016/j.marchem.2021.104064 <http://dx.doi.org/10.1016/j.marchem.2021.104064>). Article PeerReviewed 2022 ftsouthampton https://doi.org/10.1016/j.marchem.2021.104064 2023-07-09T22:45:04Z Ocean acidification may shift coral reefs from a state of net ecosystem calcification (+NEC) to net ecosystem dissolution (–NEC). Changes in NEC are typically inferred from either measured or calculated total alkalinity (TA) or the dissolved calcium (Ca) to salinity ratio relative to a reference value. The alkalinity anomaly technique has historically been the primary method to estimate NEC due to the greater analytical challenges and uncertainty associated with dissolved Ca measurements in seawater. However, this method assumes that changes in salinity-normalized TA are exclusively the result of calcification and dissolution processes. In many cases, this assumption is valid, but in some environments additional processes can significantly influence seawater TA (e.g., nutrient fluxes and redox processes). Seawater Ca is unaffected or less sensitive to these processes, and therefore, Ca and TA anomalies can be used to estimate absolute or relative changes in NEC with greater confidence. Here, we present a two-year time series of monthly seawater Ca and TA measurements across the Bermuda carbonate platform and the nearby Bermuda Atlantic Time-series Study (BATS) location offshore. High precision Ca measurements (±6 μmol kg −1 ) were conducted using an improved spectrophotometric titration system and showed mostly good agreement with changes in TA over the same spatial and temporal scales. Ca and TA measurements across the Bermuda platform showed seasonal fluctuations relative to offshore waters, with +NEC during summer months and near-zero or possible –NEC (net dissolution) during winter months. These seasonal patterns were most pronounced at the inshore locations with the longest residence times (10+ days), which allow stronger biogeochemical signals to develop relative to the offshore source water. Although obtaining high accuracy and precision Ca measurements remains challenging, parallel measurements of Ca and TA from both inshore and offshore waters over a multi-annual timescale could strengthen the validity ... Article in Journal/Newspaper Ocean acidification University of Southampton: e-Prints Soton Marine Chemistry 238 104064 |
institution |
Open Polar |
collection |
University of Southampton: e-Prints Soton |
op_collection_id |
ftsouthampton |
language |
English |
description |
Ocean acidification may shift coral reefs from a state of net ecosystem calcification (+NEC) to net ecosystem dissolution (–NEC). Changes in NEC are typically inferred from either measured or calculated total alkalinity (TA) or the dissolved calcium (Ca) to salinity ratio relative to a reference value. The alkalinity anomaly technique has historically been the primary method to estimate NEC due to the greater analytical challenges and uncertainty associated with dissolved Ca measurements in seawater. However, this method assumes that changes in salinity-normalized TA are exclusively the result of calcification and dissolution processes. In many cases, this assumption is valid, but in some environments additional processes can significantly influence seawater TA (e.g., nutrient fluxes and redox processes). Seawater Ca is unaffected or less sensitive to these processes, and therefore, Ca and TA anomalies can be used to estimate absolute or relative changes in NEC with greater confidence. Here, we present a two-year time series of monthly seawater Ca and TA measurements across the Bermuda carbonate platform and the nearby Bermuda Atlantic Time-series Study (BATS) location offshore. High precision Ca measurements (±6 μmol kg −1 ) were conducted using an improved spectrophotometric titration system and showed mostly good agreement with changes in TA over the same spatial and temporal scales. Ca and TA measurements across the Bermuda platform showed seasonal fluctuations relative to offshore waters, with +NEC during summer months and near-zero or possible –NEC (net dissolution) during winter months. These seasonal patterns were most pronounced at the inshore locations with the longest residence times (10+ days), which allow stronger biogeochemical signals to develop relative to the offshore source water. Although obtaining high accuracy and precision Ca measurements remains challenging, parallel measurements of Ca and TA from both inshore and offshore waters over a multi-annual timescale could strengthen the validity ... |
format |
Article in Journal/Newspaper |
author |
Griffin, Alyssa J. Anderson, Zachary Ballard, John Bates, Nicholas R. Garley, Rebecca Johnson, Rod Martz, Todd Pacheco, Fernando Takeshita, Yuichiro Andersson, Andreas J. |
spellingShingle |
Griffin, Alyssa J. Anderson, Zachary Ballard, John Bates, Nicholas R. Garley, Rebecca Johnson, Rod Martz, Todd Pacheco, Fernando Takeshita, Yuichiro Andersson, Andreas J. Seasonal changes in seawater calcium and alkalinity in the Sargasso Sea and across the Bermuda carbonate platform |
author_facet |
Griffin, Alyssa J. Anderson, Zachary Ballard, John Bates, Nicholas R. Garley, Rebecca Johnson, Rod Martz, Todd Pacheco, Fernando Takeshita, Yuichiro Andersson, Andreas J. |
author_sort |
Griffin, Alyssa J. |
title |
Seasonal changes in seawater calcium and alkalinity in the Sargasso Sea and across the Bermuda carbonate platform |
title_short |
Seasonal changes in seawater calcium and alkalinity in the Sargasso Sea and across the Bermuda carbonate platform |
title_full |
Seasonal changes in seawater calcium and alkalinity in the Sargasso Sea and across the Bermuda carbonate platform |
title_fullStr |
Seasonal changes in seawater calcium and alkalinity in the Sargasso Sea and across the Bermuda carbonate platform |
title_full_unstemmed |
Seasonal changes in seawater calcium and alkalinity in the Sargasso Sea and across the Bermuda carbonate platform |
title_sort |
seasonal changes in seawater calcium and alkalinity in the sargasso sea and across the bermuda carbonate platform |
publishDate |
2022 |
url |
https://eprints.soton.ac.uk/453071/ |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_relation |
Griffin, Alyssa J., Anderson, Zachary, Ballard, John, Bates, Nicholas R., Garley, Rebecca, Johnson, Rod, Martz, Todd, Pacheco, Fernando, Takeshita, Yuichiro and Andersson, Andreas J. (2022) Seasonal changes in seawater calcium and alkalinity in the Sargasso Sea and across the Bermuda carbonate platform. Marine Chemistry, 238, 104064, [104064]. (doi:10.1016/j.marchem.2021.104064 <http://dx.doi.org/10.1016/j.marchem.2021.104064>). |
op_doi |
https://doi.org/10.1016/j.marchem.2021.104064 |
container_title |
Marine Chemistry |
container_volume |
238 |
container_start_page |
104064 |
_version_ |
1772818519848648704 |