Date of Completion

8-10-2020

Embargo Period

8-9-2020

Keywords

dissolved gases, sea spray, climate change, air-sea exchange, time series

Major Advisor

Penny Vlahos

Associate Advisor

Edward C. Monahan

Associate Advisor

James Edson

Field of Study

Oceanography

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Changing climate scenarios predict a variety of effects across land, ocean, and atmosphere. In this dissertation the effect of several climate change related phenomena on dissolved gases in the coastal ocean and across the ocean-atmosphere interface is examined. Warming temperature, as predicted by the IPCC (2014), has direct impacts on the capacity of water to act as a reservoir for dissolved gases through its effect on their solubility (Chang, 2010). The first portion of this dissertation addresses dissolved gases in a coastal estuary, where warming is expected to be accelerated relative to the open ocean. A representative gas, oxygen, is examined in the context of temperature and salinity. A 25 year data set in Long Island Sound (UConn_2016_DEEP_LIS_Data) was used in order to assess these trends. Temperature was found to be increasing at an average rate of 0.08 ± 0.03 °C yr-1 while dissolved oxygen decreased at a rate of 0.03 ±0.01 mg L-1 yr-1. Correlating the solubility of dissolved oxygen and temperature trends found that the temperature increase was potentially responsible for 33-100% of the observed decrease in oxygen over the time period sampled. This has implications for both the management and the understanding of reservoirs of dissolved gases. Climate change scenarios also predict an increase in both the number and severity of extreme weather events (IPCC, 2014). This is likely to increase the occurrence of sea spray and any gas exchange associated with those droplets. Due to sampling difficulties, current parameterizations of sea spray generation and any associated exchange are not well constrained. Building on the microphysical framework provided by the Andreas (2013) model, a model of the gas transfer associated with an individual droplet, with the intention of scaling to global relevance, is the secondary focus of this dissertation. It was found that, at wind speeds >20 m·s-1, sea spray has the capacity to contribute to gas flux and at 30 m·s-1 may be on the same order of magnitude as the general interfacial flux for certain gases. This contribution appears to have particular significance for regions of the Southern Ocean and storm events.

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