Amplified bottom water acidification rates on the Bering Sea shelf from 1970–2022

Details

• Journal Title:
  Biogeosciences
• Personal Author:
  Pilcher, Darren J. ; Cross, Jessica N. ; Monacci, Natalie ; Mu, Linquan ; Kearney, Kelly A. ; Hermann, Albert J. ; Cheng, Wei
• NOAA Program & Office:
  OAR (Oceanic and Atmospheric Research) ; CICOES (Cooperative Institute for Climate, Ocean and Ecosystem Studies) ; PMEL (Pacific Marine Environmental Laboratory) ; NMFS (National Marine Fisheries Service) ; AFSC (Alaska Fisheries Science Center)
• Description:
  The Bering Sea shelf supports a highly productive marine ecosystem that is vulnerable to ocean acidification (OA) due to the cold, carbon-rich waters. Previous observational evidence suggests that bottom waters on the shelf are already seasonally undersaturated with respect to aragonite (i.e. Ωarag<1) and that OA will continue to increase the spatial extent, duration, and intensity of these conditions. Here, we use a regional ocean biogeochemical model to simulate changes in ocean carbon chemistry for the Bering Sea shelf from 1970–2022. Over this timeframe, model results suggest that surface Ωarag decreases by −0.043 per decade and surface pH by −0.014 per decade, comparable to observed global rates of OA. However, bottom water pH decreases at twice the rate of surface pH, while bottom [H+] decreases at nearly 3 times the rate of surface [H+]. This amplified bottom water acidification has emerged over the past 25 years and is likely driven by a combination of anthropogenic carbon accumulation and increasing primary productivity and subsurface respiration and remineralization. Due to this enhanced bottom water acidification, the spatial extent of bottom waters with Ωarag<1 has greatly expanded over the past 2 decades, along with pH conditions harmful to red king crab. Interannual variability in surface and bottom Ωarag, pH, and [H+] has also increased over the past 2 decades, resulting in part from the increased physical climate variability. We also find that the Bering Sea shelf is a net annual carbon sink of 1.1–7.9 Tg C yr−1, with the range resulting from the difference in the two different atmospheric forcing reanalysis products used. Seasonally, the shelf is a significant carbon sink from April–October but a somewhat weaker carbon source from November–March.
• Source:
  Biogeosciences, 22(12), 3103-3125
• Series:
  PMEL contribution   no. 5619
• DOI:
  https://doi.org/10.5194/bg-22-3103-2025
• ISSN:
  1726-4189
• Format:
  pdf
• Publisher:
  Copernicus GmbH
• Document Type:
  Journal Article
• Funding:
  Grant no. NA20OAR4320271
• License:
  https://creativecommons.org/licenses/by/4.0/
• Rights Information:
  CC BY
• Compliance:
  Submitted
• Main Document Checksum:
  urn:sha-512:b03910225e8e3bceb8762a109fdbc49c17c161913ce4a0c4257e1c4968198b7fc7b74850e98921170b0132ea6f811e4515393bf3c57d1afb8b8bce3772da32dd
• Download URL:
  https://repository.library.noaa.gov/view/noaa/71255/noaa_71255_DS1.pdf
• File Type:
  [PDF - 8.55 MB ]