Moving ecological and biogeochemical transitions across the North Pacific

In the North Pacific Ocean, nutrient rich surface waters flow south from the subpolar gyre through a transitional region and into the subtropics. Along the way, nutrients are used, recycled, and exported, leading to lower biomass and a commensurate change in ecosystem structure moving southward. We...

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Main Authors: Follett, Christopher L, Dutkiewicz, Stephanie, Forget, Gael, Cael, BB, Follows, Michael J
Other Authors: Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Format: Article
Language:English
Published: Wiley 2021
Online Access:https://hdl.handle.net/1721.1/135628
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author Follett, Christopher L
Dutkiewicz, Stephanie
Forget, Gael
Cael, BB
Follows, Michael J
author2 Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
author_facet Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Follett, Christopher L
Dutkiewicz, Stephanie
Forget, Gael
Cael, BB
Follows, Michael J
author_sort Follett, Christopher L
collection MIT
description In the North Pacific Ocean, nutrient rich surface waters flow south from the subpolar gyre through a transitional region and into the subtropics. Along the way, nutrients are used, recycled, and exported, leading to lower biomass and a commensurate change in ecosystem structure moving southward. We focus on the region between the two gyres (the Transition Zone) using a coupled biophysical ocean model, remote sensing, floats, and cruise data to explore the nature of the physical, biogeochemical, and ecological fields in this region. Nonlinear interactions between biological processes and the meridional gradient in nutrient supply lead to sharp shifts across this zone. These transitions between a southern region with more uniform biological and biogeochemical properties and steep meridional gradients to the north are diagnosed from extrema in the first derivative of the properties with latitude. Some transitions like that for chlorophyll a (the transition zone chlorophyll front [TZCF]) experience large seasonal excursions while the location of the transitions in other properties moves very little. The seasonal shifts are not caused by changes in the horizontal flow field, but rather by the interaction of seasonal, depth related, forcing with the mean latitudinal gradients. Focusing on the TZCF as a case study, we express its phase velocity in terms of vertical nutrient flux and internal ecosystem processes, demonstrating their nearly equal influence on its motion. This framework of propagating biogeochemical transitions can be systematically expanded to better understand the processes that structure ecosystems and biogeochemistry in the North Pacific and beyond.
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spelling mit-1721.1/1356282023-03-01T20:33:32Z Moving ecological and biogeochemical transitions across the North Pacific Follett, Christopher L Dutkiewicz, Stephanie Forget, Gael Cael, BB Follows, Michael J Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences In the North Pacific Ocean, nutrient rich surface waters flow south from the subpolar gyre through a transitional region and into the subtropics. Along the way, nutrients are used, recycled, and exported, leading to lower biomass and a commensurate change in ecosystem structure moving southward. We focus on the region between the two gyres (the Transition Zone) using a coupled biophysical ocean model, remote sensing, floats, and cruise data to explore the nature of the physical, biogeochemical, and ecological fields in this region. Nonlinear interactions between biological processes and the meridional gradient in nutrient supply lead to sharp shifts across this zone. These transitions between a southern region with more uniform biological and biogeochemical properties and steep meridional gradients to the north are diagnosed from extrema in the first derivative of the properties with latitude. Some transitions like that for chlorophyll a (the transition zone chlorophyll front [TZCF]) experience large seasonal excursions while the location of the transitions in other properties moves very little. The seasonal shifts are not caused by changes in the horizontal flow field, but rather by the interaction of seasonal, depth related, forcing with the mean latitudinal gradients. Focusing on the TZCF as a case study, we express its phase velocity in terms of vertical nutrient flux and internal ecosystem processes, demonstrating their nearly equal influence on its motion. This framework of propagating biogeochemical transitions can be systematically expanded to better understand the processes that structure ecosystems and biogeochemistry in the North Pacific and beyond. 2021-10-27T20:24:20Z 2021-10-27T20:24:20Z 2021 2021-09-16T16:11:36Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/135628 en 10.1002/lno.11763 Limnology and Oceanography Creative Commons Attribution 4.0 International license https://creativecommons.org/licenses/by/4.0/ application/pdf Wiley Wiley
spellingShingle Follett, Christopher L
Dutkiewicz, Stephanie
Forget, Gael
Cael, BB
Follows, Michael J
Moving ecological and biogeochemical transitions across the North Pacific
title Moving ecological and biogeochemical transitions across the North Pacific
title_full Moving ecological and biogeochemical transitions across the North Pacific
title_fullStr Moving ecological and biogeochemical transitions across the North Pacific
title_full_unstemmed Moving ecological and biogeochemical transitions across the North Pacific
title_short Moving ecological and biogeochemical transitions across the North Pacific
title_sort moving ecological and biogeochemical transitions across the north pacific
url https://hdl.handle.net/1721.1/135628
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