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Data from five sites of the International Long Term Ecological Research (ILTER) network in the North-Eastern Pacific, Western Arctic Ocean, Northern Baltic Sea, South-Eastern North Sea and in the Western Mediterranean Sea were analyzed by dynamic factor analysis (DFA) to trace common multi-year trends in abundance and composition of phytoplankton, benthic fauna and temperate reef fish. Multiannual trends were related to climate and environmental variables to study interactions. Two common trends in biological responses were detected, with temperature and climate indices as explanatory variables in four of the five LTER sites considered. Only one trend was observed at the fifth site, the Northern Baltic Sea, where no explanatory variables were identified. Our findings revealed quasi-synchronous biological shifts in the different marine ecosystems coincident with the 2000 climatic regime shift and provided evidence on a possible further biological shift around 2010. The observed biological modifications were coupled with abrupt or continuous increase in sea water and air temperature confirming the key-role of temperature in structuring marine communities.
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Multidecadal Regime Shifts in North Pacific Subtropical Mode Water Formation in a Coupled Atmosphere‐Ocean‐Sea Ice Model
Abstract A regime shift in the formation mechanisms of the North Pacific subtropical mode water (NPSTMW) and its causes were investigated using a 2,000‐year‐long pre‐industrial control simulation of a fully coupled atmosphere‐ocean‐sea ice model. The volume budget analysis revealed that the air‐sea flux and ocean dynamics (OD) were the two primary driving mechanisms for NPSTMW formation, but their relative importance has periodically alternated in multidecadal timescales of approximately 50–70 years. The regime shift of the NPSTMW formation was closely related to the meridional (50 years) and zonal (70 years) movements of the Aleutian Low (AL). When AL shifted to the south or east, it induces the sea surface height anomalies propagating westward from the central North Pacific and preconditions the NPSTMW formation, thus the OD become relatively more important.
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- Award ID(s):
- 2040073
- PAR ID:
- 10443992
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 49
- Issue:
- 19
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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