Developing in situ instrumentation to monitor anthropogenic change
type: CreativeWork
description: To predict and mitigate anthropogenic impacts on the ocean, we must understand the underlying systems that govern the ocean’s response to inputs (e.g. carbon dioxide, pollutants). Analytical models can be used to generate predictions and simulate intervention strategies, but they must be grounded with empirical observations. Unfortunately, there exists a technological gap: in situ instrumentation is often lacking or nonexistent for key parameters influenced by anthropogenic inputs. While discrete bottle samples can be collected and analyzed for these parameters, their limited spatiotemporal resolution constrains scientific inquiry. To help fill the technological gap, this dissertation presents the development of instrumentation for the ocean inorganic carbon system and microplastics. The first few chapters present the development process of CSPEC, a deep-sea laser spectrometer designed to measure the ocean carbon system through alternating measurements of the partial pressure of carbon dioxide (pCO2) and dissolved inorganic carbon (DIC). CSPEC uses tunable diode laser absorption spectroscopy (TDLAS) to measure the CO2 content of dissolved gas extracted via a membrane inlet. Chapter 2 derives membrane equilibration dynamics from first principles, thus enabling informed design decisions. The analytical results showed that cross-sensitivity to other dissolved gases can be introduced by the equilibration method, regardless of the specificity of the gas-side instrumentation. A new method, hybrid equilibration, leverages the membrane equilibration dynamics to improve time response without incurring cross-sensitivity. Chapter 3 presents POCO, a surface pCO2 instrument that employs TDLAS and a depth-compatible membrane inlet. Through laboratory and field-testing, POCO demonstrated that hybrid equilibration overcame the gas flux limitation of deep-sea membrane inlets. Chapter 4 presents CSPEC, which successfully mapped the carbon system near different hydrothermal features a…
abstract: To predict and mitigate anthropogenic impacts on the ocean, we must understand the underlying systems that govern the ocean’s response to inputs (e.g. carbon dioxide, pollutants). Analytical models can be used to generate predictions and simulate intervention strategies, but they must be grounded with empirical observations. Unfortunately, there exists a technological gap: in situ instrumentation is often lacking or nonexistent for key parameters influenced by anthropogenic inputs. While discrete bottle samples can be collected and analyzed for these parameters, their limited spatiotemporal resolution constrains scientific inquiry. To help fill the technological gap, this dissertation presents the development of instrumentation for the ocean inorganic carbon system and microplastics. The first few chapters present the development process of CSPEC, a deep-sea laser spectrometer designed to measure the ocean carbon system through alternating measurements of the partial pressure of carbon dioxide (pCO2) and dissolved inorganic carbon (DIC). CSPEC uses tunable diode laser absorption spectroscopy (TDLAS) to measure the CO2 content of dissolved gas extracted via a membrane inlet. Chapter 2 derives membrane equilibration dynamics from first principles, thus enabling informed design decisions. The analytical results showed that cross-sensitivity to other dissolved gases can be introduced by the equilibration method, regardless of the specificity of the gas-side instrumentation. A new method, hybrid equilibration, leverages the membrane equilibration dynamics to improve time response without incurring cross-sensitivity. Chapter 3 presents POCO, a surface pCO2 instrument that employs TDLAS and a depth-compatible membrane inlet. Through laboratory and field-testing, POCO demonstrated that hybrid equilibration overcame the gas flux limitation of deep-sea membrane inlets. Chapter 4 presents CSPEC, which successfully mapped the carbon system near different hydrothermal features a…
author: Colson, Beckett C.
language: en_US
keywords: In situ, Disssolved inorganic carbon, Microplastics
date published: 2023-02
date modified: 2026-07-27T22:05:06Z
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/1912/29461

PropertyValue
property ID: DOI
value: 10.1575/1912/29461