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Salish Sea Response to Global Climate Change, Sea Level Rise, and Future Nutrient Loads
Author(s) -
Khangaonkar Tarang,
Nugraha Adi,
Xu Wenwei,
Balaguru Karthik
Publication year - 2019
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2018jc014670
Subject(s) - environmental science , climate change , oceanography , representative concentration pathways , hypoxia (environmental) , estuary , ocean acidification , algal bloom , global warming , nutrient , climatology , phytoplankton , climate model , ecology , geology , biology , oxygen , chemistry , organic chemistry
Abstract Given annual occurrences of hypoxia, harmful algal blooms, and evidence of coastal acidification, the potential impacts of climate change on water quality are of increasing concern in the U.S. Pacific Northwest estuaries such as the Salish Sea. While large‐scale global climate projections are well documented, our understanding of the nearshore estuarine‐scale response is not as well developed. In this study, the future response within the Salish Sea fjord‐like environment was examined using the Salish Sea Model driven by downscaled outputs from the National Center for Atmospheric Research climate model Community Earth System Model. We simulated a single projection of 95‐year change under the representative concentration pathway 8.5 greenhouse gas emissions scenario. Results indicate that higher temperatures, lower pH, and decreased dissolved oxygen levels in the upwelled shelf waters in the future would propagate into the Salish Sea. Results point to potential changes in average Salish Sea temperature (≈+1.51 °C), dissolved oxygen (≈−0.77 mg/L), and pH (acidification −0.18 units) in the Y2095 relative to historical Y2000. The algal biomass in the Salish Sea could increase by ≈23% with a potential species shift from diatoms toward dinoflagellates. The region of annually recurring hypoxia could increase from <1% today to ≈16% in the future. The results suggest that the future response in the Salish Sea is less severe relative to the change predicted near the continental shelf boundary. This resilience of the Salish Sea may be attributed to the existence of strong vertical circulation cells that provide mitigation and serve as a physical buffer, thus keeping waters cooler, more oxygenated, and less acidic.