Distributional models of ocean carbon export
type: CreativeWork
description: Each year, surface ocean ecosystems export sinking particles containing gigatons of carbon into the ocean’s interior. This particle flux connects the entire ocean microbiome and constitutes a fundamental aspect of marine microbial ecology and biogeochemical cycles. Particle flux is also variable and intricately complex, impeding its mechanistic or quantitative description. In this thesis we pair compilations of available data with novel mathematical models to explore the relationships between particle flux and other key variables – temperature, net primary production, and depth. Particular use is made of (probability) distributional descriptions of quantities that are known to vary appreciably. First, using established thermodynamic dependencies for primary production and respiration, a simple mechanistic model is developed relating export efficiency (i.e. the fraction of primary production that is exported out of the surface ocean via particle flux) to temperature. The model accounts for the observed variability in export efficiency due to temperature without idealizing out the remaining variability that evinces particle flux’s complexity. This model is then used to estimate the metabolically-driven change in average export efficiency over the era of long-term global sea surface temperature records, and it is shown that the underlying mechanism may help explain glacial-interglacial atmospheric carbon dioxide drawdown. The relationship between particle flux and net primary production is then explored. Given that these are inextricable but highly variable and measured on different effective scales, it is hypothesized that a quantitative relationship emerges between collections of the two measurements – i.e. that they can be related not measurement-by-measurement but rather via their probability distributions. It is shown that on large spatial or temporal scales both are consistent with lognormal distributions, as expected if each is considered as the collective resul…
abstract: Each year, surface ocean ecosystems export sinking particles containing gigatons of carbon into the ocean’s interior. This particle flux connects the entire ocean microbiome and constitutes a fundamental aspect of marine microbial ecology and biogeochemical cycles. Particle flux is also variable and intricately complex, impeding its mechanistic or quantitative description. In this thesis we pair compilations of available data with novel mathematical models to explore the relationships between particle flux and other key variables – temperature, net primary production, and depth. Particular use is made of (probability) distributional descriptions of quantities that are known to vary appreciably. First, using established thermodynamic dependencies for primary production and respiration, a simple mechanistic model is developed relating export efficiency (i.e. the fraction of primary production that is exported out of the surface ocean via particle flux) to temperature. The model accounts for the observed variability in export efficiency due to temperature without idealizing out the remaining variability that evinces particle flux’s complexity. This model is then used to estimate the metabolically-driven change in average export efficiency over the era of long-term global sea surface temperature records, and it is shown that the underlying mechanism may help explain glacial-interglacial atmospheric carbon dioxide drawdown. The relationship between particle flux and net primary production is then explored. Given that these are inextricable but highly variable and measured on different effective scales, it is hypothesized that a quantitative relationship emerges between collections of the two measurements – i.e. that they can be related not measurement-by-measurement but rather via their probability distributions. It is shown that on large spatial or temporal scales both are consistent with lognormal distributions, as expected if each is considered as the collective resul…
author: Barry, Brendan
language: en_US
keywords: Signal processing, Reynolds stress, Ocean currents, Oceanographic instruments
date published: 2019-02
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/1912/10825

PropertyValue
property ID: DOI
value: 10.1575/1912/10825