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Abstract This study investigates the biogeochemical drivers of aragonite saturation state (ΩAr) in Baffin Bay, with a focus on the relatively undersampled west Greenland shelf. Our findings reveal two main depth‐dependant processes controlling the spatial distribution of ΩArin Baffin Bay; within the upper 200 m, lower ΩArcoincides with increasing fractions of Arctic‐outflow waters, while below 200 m organic matter respiration decreases ΩAr. A temporal analysis comparing historical measurements from 1997 and 2004 with our 2019 data set reveals a significant decrease in the ΩArof Arctic‐outflow waters, coinciding with reduced total alkalinity (TA). However, no discernible anthropogenic ocean acidification signal is identified. Significant Arctic water fractions (20%–40%) are found to be present on the west Greenland shelf, associated with reduced TA and ΩAr. A numerical modeling simulation incorporating a passive tracer demonstrates that periodic changes in wind direction lead to a switch from onshore to offshore Ekman transport along the Baffin Island current, transporting Arctic waters toward the west Greenland shelf. This challenges the conventional understanding of Baffin Bay's circulation and underscores the need for further research on the region's physical oceanography. Based on salinity‐TA relationships, surface waters on the west Greenland shelf have a significantly lower meteoric TA end‐member compared to waters of the Baffin Island Current in western Baffin Bay. The low eastern TA freshwater end‐member agrees well with recent glacial meltwater TA measurements, suggesting that glacial meltwater is the main freshwater source to surface waters on the west Greenland shelf.
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Carbonate Chemistry and the Potential for Acidification in Georgia Coastal Marshes and the South Atlantic Bight, USA
Abstract In coastal regions and marginal bodies of water, the increase in partial pressure of carbon dioxide (pCO2) in many instances is greater than that of the open ocean due to terrestrial (river, estuarine, and wetland) influences, decreasing buffering capacity and/or increasing water temperatures. Coastal oceans receive freshwater from rivers and groundwater as well as terrestrial-derived organic matter, both of which have a direct influence on coastal carbonate chemistry. The objective of this research is to determine if coastal marshes in Georgia, USA, may be “hot-spots” for acidification due to enhanced inorganic carbon sources and if there is terrestrial influence on offshore acidification in the South Atlantic Bight (SAB). The results of this study show that dissolved inorganic carbon (DIC) and total alkalinity (TA) are elevated in the marshes compared to predictions from conservative mixing of the freshwater and oceanic end-members, with accompanying pH around 7.2 to 7.6 within the marshes and aragonite saturation states (ΩAr) <1. In the marshes, there is a strong relationship between the terrestrial/estuarine-derived organic and inorganic carbon and acidification. Comparisons of pH, TA, and DIC to terrestrial organic material markers, however, show that there is little influence of terrestrial-derived organic matter on shelf acidification during this period in 2014. In addition, ΩArincreases rapidly offshore, especially in drier months (July). River stream flow during 2014 was anomalously low compared to climatological means; therefore, offshore influences from terrestrial carbon could also be decreased. The SAB shelf may not be strongly influenced by terrestrial inputs to acidification during drier than normal periods; conversely, shelf waters that are well-buffered against acidification may not play a significant role in mitigating acidification within the Georgia marshes.
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- Award ID(s):
- 1832178
- PAR ID:
- 10462001
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Estuaries and Coasts
- Volume:
- 47
- Issue:
- 1
- ISSN:
- 1559-2723
- Format(s):
- Medium: X Size: p. 76-90
- Size(s):
- p. 76-90
- Sponsoring Org:
- National Science Foundation
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