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Full-Text Articles in Physical Sciences and Mathematics
In The Margins: Reconsidering The Range And Contribution Of Diazotrophs In Nearshore Environments, Corday R. Selden
In The Margins: Reconsidering The Range And Contribution Of Diazotrophs In Nearshore Environments, Corday R. Selden
OES Theses and Dissertations
Dinitrogen (N2) fixation enables primary production and, consequently, carbon dioxide drawdown in nitrogen (N) limited marine systems, exerting a powerful influence over the coupled carbon and N cycles. Our understanding of the environmental factors regulating its distribution and magnitude are largely based on the range and sensitivity of one genus, Trichodesmium. However, recent work suggests that the niche preferences of distinct diazotrophic (N2 fixing) clades differ due to their metabolic and ecological diversity, hampering efforts to close the N budget and model N2 fixation accurately. Here, I explore the range of N2 fixation …
Sodium-Calcium Ratios In The Planktic Foraminifera Trilobatus Sacculifer As A Proxy For Sea Surface Salinity, Colton Steele Watkins
Sodium-Calcium Ratios In The Planktic Foraminifera Trilobatus Sacculifer As A Proxy For Sea Surface Salinity, Colton Steele Watkins
OES Theses and Dissertations
Recent culture and field studies have found a significant positive correlation between seawater salinity and the incorporation of sodium into foraminiferal calcite, suggesting a potential new proxy for reconstructing past changes in sea surface salinity (SSS) (Mezger et al., 2016 and Bertlich et al., 2018). In order to test the applicability of this new proxy in an open-ocean setting, Na/Ca ratios in the planktic foraminifera Trilobatus sacculifer (T. sacculifer Na/Ca) were measured from a suite of sediment core tops spanning a natural salinity gradient from the North Atlantic subtropical gyre to the South Atlantic subtropical gyre. Initial results from …
Diatom Community Composition Shifts Driven By Coherent Cyclonic Mesoscale Eddies In The California Current System, Zuzanna Maria Abdala
Diatom Community Composition Shifts Driven By Coherent Cyclonic Mesoscale Eddies In The California Current System, Zuzanna Maria Abdala
OES Theses and Dissertations
The California Current System (CCS) is characterized by an equatorward flowing eastern boundary current, as well as seasonal wind-driven coastal upwelling which supplies nutrient-rich waters to the surface and drives high coastal productivity. Cyclonic mesoscale eddies form off the coast in the CCS where they trap the highly productive upwelled coastal waters, along with their resident planktonic communities, and transport them offshore into the more oligotrophic California Current waters. The interaction between waters within and outside of the eddies is limited, and so the eddies act as natural mesocosms, where the resident phytoplankton population undergo ecological succession as the eddy …