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Abstract Multiple aquatic ecosystems (pond, lake, river, lagoon, and ocean) on the Arctic Coastal Plain near Utqiaġvik, Alaska, USA, were visited to determine their relative atmospheric CO2flux and how this may have changed over time. The nearshore coastal waters and large freshwater lakes were small sources of atmospheric CO2, whereas smaller waterbodies were substantial sources.pCO2was linked to dissolved organic carbon concentrations across broad spatial and temporal scales, with greater concentrations found in smaller freshwater systems (i.e., ponds and rivers). On a day‐to‐day basis, water temperatures appeared to be the strongest driver ofpCO2levels in tundra ponds, where warmer temperatures likely stimulated microbial mineralization of carbon in both aquatic and hydrologically linked terrestrial environments. Large rainfall events, which may lead to inflow of carbon‐rich groundwater into these ponds, also were associated with increased daily averagepCO2. Based on comparison to historical data, we estimate that CO2concentrations in tundra ponds have increased more than 1.8 times over the past 40 years. Quantifying CO2flux from these abundant aquatic ecosystems on the Arctic Coastal Plain and elsewhere in the high northern latitudes will likely have important implications for furthering understanding of landscape‐level and nearshore carbon dynamics in the Arctic.
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This content will become publicly available on June 21, 2026
Carbon dioxide fluxes of Arctic coastal ecosystems controlled by seasonal patterns of land‐to‐ocean connectivity
Abstract The strength of coastal Arctic Ocean CO2uptake is vulnerable to landscape‐scale changes such as hydrological intensification, changing climate, and alterations to terrestrial and aquatic biogeochemistry. Across a period of 4 yr (2019–2023) and three distinct sampling periods, we visited five coastal ecosystems of the Beaufort Sea with varying barrier island coverage to understand drivers of Arctic coastal CO2flux. The ice cover sampling period was characterized by the highest pCO2saturation and dissolved O2undersaturation. We observed a > 100μatm difference in pCO2over shallow depths (up to 2 m) at 73% of ice‐cover site visits. Notably, the geomorphology of barrier islands and channels controlled the flushing of colder Beaufort Sea waters across the systems and influenced the strength and appearance of both vertical thermohaline and pCO2stratification. The ice breakup period reflected spring freshet and was a net CO2sink during sampling, likely related to freshwater riverine dilution, CaCO3dissolution from sea ice melt, and water column algal activity. During the open water sampling period, the interaction of marine and terrestrial contributions predicted the strength of the CO2efflux, with freshwater inputs introducing higher temperatures and organic material, which increased remineralization. The capacity of these systems to act as CO2sources or sinks varies throughout the year and is largely driven by geomorphic conditions. Any spatially integrative studies of CO2flux or coastal productivity should consider the physical and biogeochemical heterogeneity of Arctic coastal ecosystems.
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- Award ID(s):
- 2322664
- PAR ID:
- 10629789
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Limnology and Oceanography
- Volume:
- 70
- Issue:
- 8
- ISSN:
- 0024-3590
- Format(s):
- Medium: X Size: p. 2175-2191
- Size(s):
- p. 2175-2191
- Sponsoring Org:
- National Science Foundation
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