Subseafloor Porewater Paleosalinity and Nitrogen Isotopes
Sedimentary porewater chemical and isotopic profiles contain complex records of past bottom water composition which are overprinted by in situ biotic and abiotic reactions. We developed a density-based method to determined relic deep water salinities and applied it to map global-scale water mass pro...
Main Author: | |
---|---|
Format: | Text |
Language: | English |
Published: |
DigitalCommons@URI
2020
|
Subjects: | |
Online Access: | https://digitalcommons.uri.edu/dissertations/AAI27668290 |
id |
ftunivrhodeislan:oai:digitalcommons.uri.edu:dissertations-4548 |
---|---|
record_format |
openpolar |
spelling |
ftunivrhodeislan:oai:digitalcommons.uri.edu:dissertations-4548 2023-05-15T17:45:37+02:00 Subseafloor Porewater Paleosalinity and Nitrogen Isotopes Homola, Kira Louise 2020-01-01T08:00:00Z https://digitalcommons.uri.edu/dissertations/AAI27668290 ENG eng DigitalCommons@URI https://digitalcommons.uri.edu/dissertations/AAI27668290 Dissertations and Master's Theses (Campus Access) Biogeochemistry|Climate Change text 2020 ftunivrhodeislan 2021-06-29T19:30:38Z Sedimentary porewater chemical and isotopic profiles contain complex records of past bottom water composition which are overprinted by in situ biotic and abiotic reactions. We developed a density-based method to determined relic deep water salinities and applied it to map global-scale water mass properties and distributions in the deep northwest Atlantic at four previously unsampled sites. Paleosalinities determined by density have higher precision and accuracy than previously published results and confirm the northward expansion of southern deep water and a reversal in the Atlantic’s bottom water meridional salinity gradient during the Last Glacial Maximum (Chapters 1 & 2). Nitrogen isotopic composition profiles of deeply buried porewaters are a unique dataset used to distinguish between biotic and abiotic nitrogen reactions under conditions that approach the canonical temperature and pressure limits of life. We attribute observed variations in nitrogen concentrations and isotopic compositions of porewater and sediment to a variety of microbially mediated processes including assimilation, ammonification, sulfate reducing ammonia oxidation, accretion, dissolution, and illitization (Chapter 3). Text Northwest Atlantic University of Rhode Island: DigitalCommons@URI |
institution |
Open Polar |
collection |
University of Rhode Island: DigitalCommons@URI |
op_collection_id |
ftunivrhodeislan |
language |
English |
topic |
Biogeochemistry|Climate Change |
spellingShingle |
Biogeochemistry|Climate Change Homola, Kira Louise Subseafloor Porewater Paleosalinity and Nitrogen Isotopes |
topic_facet |
Biogeochemistry|Climate Change |
description |
Sedimentary porewater chemical and isotopic profiles contain complex records of past bottom water composition which are overprinted by in situ biotic and abiotic reactions. We developed a density-based method to determined relic deep water salinities and applied it to map global-scale water mass properties and distributions in the deep northwest Atlantic at four previously unsampled sites. Paleosalinities determined by density have higher precision and accuracy than previously published results and confirm the northward expansion of southern deep water and a reversal in the Atlantic’s bottom water meridional salinity gradient during the Last Glacial Maximum (Chapters 1 & 2). Nitrogen isotopic composition profiles of deeply buried porewaters are a unique dataset used to distinguish between biotic and abiotic nitrogen reactions under conditions that approach the canonical temperature and pressure limits of life. We attribute observed variations in nitrogen concentrations and isotopic compositions of porewater and sediment to a variety of microbially mediated processes including assimilation, ammonification, sulfate reducing ammonia oxidation, accretion, dissolution, and illitization (Chapter 3). |
format |
Text |
author |
Homola, Kira Louise |
author_facet |
Homola, Kira Louise |
author_sort |
Homola, Kira Louise |
title |
Subseafloor Porewater Paleosalinity and Nitrogen Isotopes |
title_short |
Subseafloor Porewater Paleosalinity and Nitrogen Isotopes |
title_full |
Subseafloor Porewater Paleosalinity and Nitrogen Isotopes |
title_fullStr |
Subseafloor Porewater Paleosalinity and Nitrogen Isotopes |
title_full_unstemmed |
Subseafloor Porewater Paleosalinity and Nitrogen Isotopes |
title_sort |
subseafloor porewater paleosalinity and nitrogen isotopes |
publisher |
DigitalCommons@URI |
publishDate |
2020 |
url |
https://digitalcommons.uri.edu/dissertations/AAI27668290 |
genre |
Northwest Atlantic |
genre_facet |
Northwest Atlantic |
op_source |
Dissertations and Master's Theses (Campus Access) |
op_relation |
https://digitalcommons.uri.edu/dissertations/AAI27668290 |
_version_ |
1766148772017995776 |