reference : The importance of freshwater to spatial variability of aragonite saturation state in the Gulf of Alaska

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/report/nca4/reference/480b9fbf-ed78-4f41-be7e-c6023a317e6b
Bibliographic fields
reftype Journal Article
Abstract High-latitude and subpolar regions like the Gulf of Alaska (GOA) are more vulnerable than equatorial regions to rising carbon dioxide (CO2) levels, in part due to local processes that amplify the global signal. Recent field observations have shown that the shelf of the GOA is currently experiencing seasonal corrosive events (carbonate mineral saturation states Ω, Ω < 1), including suppressed Ω in response to ocean acidification as well as local processes like increased low-alkalinity glacial meltwater discharge. While the glacial discharge mainly influences the inner shelf, on the outer shelf, upwelling brings corrosive waters from the deep GOA. In this work, we develop a high-resolution model for carbon dynamics in the GOA, identify regions of high variability of Ω, and test the sensitivity of those regions to changes in the chemistry of glacial meltwater discharge. Results indicate the importance of this climatically sensitive and relatively unconstrained regional freshwater forcing for Ω variability in the nearshore. The increase was nearly linear at 0.002 Ω per 100 µmol/kg increase in alkalinity in the freshwater runoff. We find that the local winds, biological processes, and freshwater forcing all contribute to the spatial distribution of Ω and identify which of these three is highly correlated to the variability in Ω. Given that the timing and magnitude of these processes will likely change during the next few decades, it is critical to elucidate the effect of local processes on the background ocean acidification signal using robust models, such as the one described here.
Author Siedlecki, Samantha A.; Pilcher, Darren J.; Hermann, Albert J.; Coyle, Ken; Mathis, Jeremy
DOI 10.1002/2017JC012791
Issue 11
Journal Journal of Geophysical Research: Oceans
Pages 8482-8502
Title The importance of freshwater to spatial variability of aragonite saturation state in the Gulf of Alaska
Volume 122
Year 2017
Bibliographic identifiers
_record_number 26070
_uuid 480b9fbf-ed78-4f41-be7e-c6023a317e6b