Insight into chemical, biological, and physical processes in coastal waters from dissolved oxygen and inert gas tracers
type: CreativeWork
description: In this thesis, I use coastal measurements of dissolved O2 and inert gases to provide insight into the chemical, biological, and physical processes that impact the oceanic cycles of carbon and dissolved gases. Dissolved O2 concentration and triple isotopic composition trace net and gross biological productivity. The saturation states of inert gases trace physical processes, such as air-water gas exchange, temperature change, and mixing, that affect all gases. First, I developed a field-deployable system that measures Ne, Ar, Kr, and Xe gas ratios in water. It has precision and accuracy of 1 % or better, enables near-continuous measurements, and has much lower cost compared to existing laboratory-based methods. The system will increase the scientific community’s access to use dissolved noble gases as environmental tracers. Second, I measured O2 and five noble gases during a cruise in Monterey Bay, California. I developed a vertical model and found that accurately parameterizing bubble-mediated gas exchange was necessary to accurately simulate the He and Ne measurements. I present the first comparison of multiple gas tracer, incubation, and sediment trap-based productivity estimates in the coastal ocean. Net community production estimated from 15NO –3 uptake and O2/Ar gave equivalent results at steady state. Underway O2/Ar measurements revealed submesoscale variability that was not apparent from daily incubations. Third, I quantified productivity by O2 mass balance and air-water gas exchange by dual tracer (3He/SF6) release during ice melt in the Bras d’Or Lakes, a Canadian estuary. The gas transfer velocity at >90% ice cover was 6% of the rate for nearly ice-free conditions. Rates of volumetric gross primary production were similar when the estuary was completely ice-covered and ice-free, and the ecosystem was on average net autotrophic during ice melt and net heterotrophic following ice melt. I present a method for incorporating the isotopic composition of H2O into …
abstract: In this thesis, I use coastal measurements of dissolved O2 and inert gases to provide insight into the chemical, biological, and physical processes that impact the oceanic cycles of carbon and dissolved gases. Dissolved O2 concentration and triple isotopic composition trace net and gross biological productivity. The saturation states of inert gases trace physical processes, such as air-water gas exchange, temperature change, and mixing, that affect all gases. First, I developed a field-deployable system that measures Ne, Ar, Kr, and Xe gas ratios in water. It has precision and accuracy of 1 % or better, enables near-continuous measurements, and has much lower cost compared to existing laboratory-based methods. The system will increase the scientific community’s access to use dissolved noble gases as environmental tracers. Second, I measured O2 and five noble gases during a cruise in Monterey Bay, California. I developed a vertical model and found that accurately parameterizing bubble-mediated gas exchange was necessary to accurately simulate the He and Ne measurements. I present the first comparison of multiple gas tracer, incubation, and sediment trap-based productivity estimates in the coastal ocean. Net community production estimated from 15NO –3 uptake and O2/Ar gave equivalent results at steady state. Underway O2/Ar measurements revealed submesoscale variability that was not apparent from daily incubations. Third, I quantified productivity by O2 mass balance and air-water gas exchange by dual tracer (3He/SF6) release during ice melt in the Bras d’Or Lakes, a Canadian estuary. The gas transfer velocity at >90% ice cover was 6% of the rate for nearly ice-free conditions. Rates of volumetric gross primary production were similar when the estuary was completely ice-covered and ice-free, and the ecosystem was on average net autotrophic during ice melt and net heterotrophic following ice melt. I present a method for incorporating the isotopic composition of H2O into …
author: Manning, Cara C.
language: en_US
keywords: Gases, Chemical oceanography
date published: 2017-02
date modified: 2026-07-27T22:05:10Z
provider: Woods Hole Oceanographic Institute
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Massachusetts Institute of Technology and Woods Hole Oceanographic Institution

PropertyValue
property ID: Handle
value: https://hdl.handle.net/1912/8589

PropertyValue
property ID: DOI
value: 10.1575/1912/8589