Marine regime shifts in ocean biogeochemical models: a case study in the Gulf of Alaska

Beaulieu, C.; Cole, H.; Henson, S. ORCID: https://orcid.org/0000-0002-3875-6802; Yool, A. ORCID: https://orcid.org/0000-0002-9879-2776; Anderson, T.R. ORCID: https://orcid.org/0000-0002-7408-1566; de Mora, L.; Buitenhuis, E.T.; Butenschön, M.; Totterdell, I.J.; Allen, J.I.. 2016 Marine regime shifts in ocean biogeochemical models: a case study in the Gulf of Alaska. Biogeosciences, 13. 4533-4553. 10.5194/bg-13-4533-2016

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Abstract/Summary

Regime shifts have been reported in many marine ecosystems, and are often expressed as an abrupt change occurring in multiple physical and biological components of the system. In the Gulf of Alaska, a regime shift in the late 1970s was observed, indicated by an abrupt increase in sea surface temperature and major shifts in the catch of many fish species. A thorough understanding of the extent and mechanisms leading to such regime shifts is challenged by data paucity in time and space. We investigate the ability of a suite of ocean biogeochemistry models of varying complexity to simulate regime shifts in the Gulf of Alaska by examining the presence of abrupt changes in time series of physical variables (sea surface temperature and mixed-layer depth), nutrients and biological variables (chlorophyll, primary productivity and plankton biomass) using change-point analysis. Our results show that some ocean biogeochemical models are capable of simulating the late 1970s shift, manifested as an abrupt increase in sea surface temperature followed by an abrupt decrease in nutrients and biological productivity. Models from low to intermediate complexity simulate an abrupt transition in the late 1970s (i.e. a significant shift from one year to the next) while the transition is smoother in higher complexity models. Our study demonstrates that ocean biogeochemical models can successfully simulate regime shifts in the Gulf of Alaska region. These models can therefore be considered useful tools to enhance our understanding of how changes in physical conditions are propagated from lower to upper trophic levels.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.5194/bg-13-4533-2016
ISSN:	17264170
Date made live:	28 Jun 2016 16:00 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/513893

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.5194/bg-13-4533-2016

ISSN:

17264170

Date made live:

28 Jun 2016 16:00 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/513893