Computational analysis of the biophysical controls on Southern Ocean phytoplankton ecosystem dynamics
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Applied Ocean Science & Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2019. Southern Ocean net community productivity plays an out sized...
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/23631 2023-05-15T18:24:42+02:00 Computational analysis of the biophysical controls on Southern Ocean phytoplankton ecosystem dynamics Rohr, Tyler 2019-02 https://hdl.handle.net/1912/23631 en_US eng Massachusetts Institute of Technology and Woods Hole Oceanographic Institution WHOI Theses https://hdl.handle.net/1912/23631 doi:10.1575/1912/23631 doi:10.1575/1912/23631 Thesis 2019 ftwhoas https://doi.org/10.1575/1912/23631 2022-05-28T23:02:54Z Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Applied Ocean Science & Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2019. Southern Ocean net community productivity plays an out sized role in regulating global biogeochemical cycling and climate dynamics. The structure of spatial-temporal variability in phytoplankton ecosystem dynamics is largely governed by physical processes but a variety of competing pathways complicate our understanding of how exactly they drive net population growth. Here, I leverage two coupled, 3-dimensional, global, numerical simulations in conjunction with remote sensing data and past observations, to improve our mechanistic understanding of how physical processes drive biology in the Southern Ocean. In Chapter 2, I show how different mechanistic pathways can control population dynamics from the bottom-up (via light, nutrients), as well as the top-down (via grazing pressure). In Chapters 3 and 4, I employ a higher resolution, eddy resolving, integration to explicitly track and examine closed eddy structures and address how they modify biomass at the mesoscale. Chapter 3 considers how simulated eddies drive bottom-up controls on phytoplankton growth and finds that division rates are, on average, amplified in anticyclones and suppressed in cyclones. Anomalous division rates are predominately fueled by an anomalous vertical iron flux driven by eddy-induced Ekman Pumping. Chapter 4 goes on to describe how anomalous division rates combine with anomalous loss rates to drive anomalous net population growth. Biological rate-based mechanisms are then compared to the potential for anomalies to evolve strictly via physical transport (i.e. dilution, stirring, advection). All together, I identify and describe dramatic regional and seasonal variability in when, where, and how different mechanisms drive phytoplankton growth throughout the Southern Ocean. Better understanding this ... Thesis Southern Ocean Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Southern Ocean |
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Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
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English |
description |
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Applied Ocean Science & Engineering at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2019. Southern Ocean net community productivity plays an out sized role in regulating global biogeochemical cycling and climate dynamics. The structure of spatial-temporal variability in phytoplankton ecosystem dynamics is largely governed by physical processes but a variety of competing pathways complicate our understanding of how exactly they drive net population growth. Here, I leverage two coupled, 3-dimensional, global, numerical simulations in conjunction with remote sensing data and past observations, to improve our mechanistic understanding of how physical processes drive biology in the Southern Ocean. In Chapter 2, I show how different mechanistic pathways can control population dynamics from the bottom-up (via light, nutrients), as well as the top-down (via grazing pressure). In Chapters 3 and 4, I employ a higher resolution, eddy resolving, integration to explicitly track and examine closed eddy structures and address how they modify biomass at the mesoscale. Chapter 3 considers how simulated eddies drive bottom-up controls on phytoplankton growth and finds that division rates are, on average, amplified in anticyclones and suppressed in cyclones. Anomalous division rates are predominately fueled by an anomalous vertical iron flux driven by eddy-induced Ekman Pumping. Chapter 4 goes on to describe how anomalous division rates combine with anomalous loss rates to drive anomalous net population growth. Biological rate-based mechanisms are then compared to the potential for anomalies to evolve strictly via physical transport (i.e. dilution, stirring, advection). All together, I identify and describe dramatic regional and seasonal variability in when, where, and how different mechanisms drive phytoplankton growth throughout the Southern Ocean. Better understanding this ... |
format |
Thesis |
author |
Rohr, Tyler |
spellingShingle |
Rohr, Tyler Computational analysis of the biophysical controls on Southern Ocean phytoplankton ecosystem dynamics |
author_facet |
Rohr, Tyler |
author_sort |
Rohr, Tyler |
title |
Computational analysis of the biophysical controls on Southern Ocean phytoplankton ecosystem dynamics |
title_short |
Computational analysis of the biophysical controls on Southern Ocean phytoplankton ecosystem dynamics |
title_full |
Computational analysis of the biophysical controls on Southern Ocean phytoplankton ecosystem dynamics |
title_fullStr |
Computational analysis of the biophysical controls on Southern Ocean phytoplankton ecosystem dynamics |
title_full_unstemmed |
Computational analysis of the biophysical controls on Southern Ocean phytoplankton ecosystem dynamics |
title_sort |
computational analysis of the biophysical controls on southern ocean phytoplankton ecosystem dynamics |
publisher |
Massachusetts Institute of Technology and Woods Hole Oceanographic Institution |
publishDate |
2019 |
url |
https://hdl.handle.net/1912/23631 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
doi:10.1575/1912/23631 |
op_relation |
WHOI Theses https://hdl.handle.net/1912/23631 doi:10.1575/1912/23631 |
op_doi |
https://doi.org/10.1575/1912/23631 |
_version_ |
1766205518938898432 |