A high-resolution geochemical proxy record of ∆14C and d18O in the Gulf of Maine using Arctica islandica shell carbonate
Coastal regions play a critical role in nutrient cycling, waste treatment and flood control and prevention, yet these productive ecosystems are among the most sensitive environments to climate change. Climate changes predicted for coming centuries pose a threat to marine ecosystems for degradation....
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ftiowastateuniv:oai:lib.dr.iastate.edu:etd-3573 2023-05-15T15:22:29+02:00 A high-resolution geochemical proxy record of ∆14C and d18O in the Gulf of Maine using Arctica islandica shell carbonate Lower, Erin Elizabeth 2012-01-01T08:00:00Z application/pdf https://lib.dr.iastate.edu/etd/12566 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=3573&context=etd en eng Iowa State University Digital Repository https://lib.dr.iastate.edu/etd/12566 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=3573&context=etd Graduate Theses and Dissertations Arctica islandica Climate Gulf of Maine North Atlantic Oceanography Paleoclimate Environmental Indicators and Impact Assessment Environmental Sciences Geochemistry text 2012 ftiowastateuniv 2018-11-26T01:38:11Z Coastal regions play a critical role in nutrient cycling, waste treatment and flood control and prevention, yet these productive ecosystems are among the most sensitive environments to climate change. Climate changes predicted for coming centuries pose a threat to marine ecosystems for degradation. Though coastal vulnerability to climate change is well documented, few coastal regions around the world have long-term monitoring records of oceanographic conditions and patterns of variability. This lack of knowledge makes it difficult to establish baseline climate conditions for coastal regions, limiting efforts to discriminate between natural cycles of variability and abnormal climate trends. Extending the coverage of available records beyond the instrumental period can help place present coastal climate into a longer historical context. To do this, geochemical proxy records can be used to reconstruct past climate conditions in rapidly changing coastal ecosystems. Here, a two century pre-bomb time series of near surface water radiocarbon activity (&Delta14C) was generated using shell material from a marine bivalve mollusk, Arctica islandica in the western interior Gulf of Maine. Additionally, a time history of potential hydrographic conditions was generated using the oxygen isotopic composition (&delta18O) of shell carbonate. In the oxygen isotope reconstruction, a persistent increase in shell &delta18O is observed between 1920 and 1980, followed by a sharp reversal of that trend into recent decades. Results also show a radiocarbon-depleted signature for the Gulf of Maine, indicating that regional hydrography is dominated by a deepwater source. A highly variable regional reservoir age offset (&DeltaR) is also observed, meaning that the record constructed here may help improve age model resolution for other reconstructions on the North American continental shelf regions of the western North Atlantic. Text Arctica islandica North Atlantic Digital Repository @ Iowa State University |
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Open Polar |
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Digital Repository @ Iowa State University |
op_collection_id |
ftiowastateuniv |
language |
English |
topic |
Arctica islandica Climate Gulf of Maine North Atlantic Oceanography Paleoclimate Environmental Indicators and Impact Assessment Environmental Sciences Geochemistry |
spellingShingle |
Arctica islandica Climate Gulf of Maine North Atlantic Oceanography Paleoclimate Environmental Indicators and Impact Assessment Environmental Sciences Geochemistry Lower, Erin Elizabeth A high-resolution geochemical proxy record of ∆14C and d18O in the Gulf of Maine using Arctica islandica shell carbonate |
topic_facet |
Arctica islandica Climate Gulf of Maine North Atlantic Oceanography Paleoclimate Environmental Indicators and Impact Assessment Environmental Sciences Geochemistry |
description |
Coastal regions play a critical role in nutrient cycling, waste treatment and flood control and prevention, yet these productive ecosystems are among the most sensitive environments to climate change. Climate changes predicted for coming centuries pose a threat to marine ecosystems for degradation. Though coastal vulnerability to climate change is well documented, few coastal regions around the world have long-term monitoring records of oceanographic conditions and patterns of variability. This lack of knowledge makes it difficult to establish baseline climate conditions for coastal regions, limiting efforts to discriminate between natural cycles of variability and abnormal climate trends. Extending the coverage of available records beyond the instrumental period can help place present coastal climate into a longer historical context. To do this, geochemical proxy records can be used to reconstruct past climate conditions in rapidly changing coastal ecosystems. Here, a two century pre-bomb time series of near surface water radiocarbon activity (&Delta14C) was generated using shell material from a marine bivalve mollusk, Arctica islandica in the western interior Gulf of Maine. Additionally, a time history of potential hydrographic conditions was generated using the oxygen isotopic composition (&delta18O) of shell carbonate. In the oxygen isotope reconstruction, a persistent increase in shell &delta18O is observed between 1920 and 1980, followed by a sharp reversal of that trend into recent decades. Results also show a radiocarbon-depleted signature for the Gulf of Maine, indicating that regional hydrography is dominated by a deepwater source. A highly variable regional reservoir age offset (&DeltaR) is also observed, meaning that the record constructed here may help improve age model resolution for other reconstructions on the North American continental shelf regions of the western North Atlantic. |
format |
Text |
author |
Lower, Erin Elizabeth |
author_facet |
Lower, Erin Elizabeth |
author_sort |
Lower, Erin Elizabeth |
title |
A high-resolution geochemical proxy record of ∆14C and d18O in the Gulf of Maine using Arctica islandica shell carbonate |
title_short |
A high-resolution geochemical proxy record of ∆14C and d18O in the Gulf of Maine using Arctica islandica shell carbonate |
title_full |
A high-resolution geochemical proxy record of ∆14C and d18O in the Gulf of Maine using Arctica islandica shell carbonate |
title_fullStr |
A high-resolution geochemical proxy record of ∆14C and d18O in the Gulf of Maine using Arctica islandica shell carbonate |
title_full_unstemmed |
A high-resolution geochemical proxy record of ∆14C and d18O in the Gulf of Maine using Arctica islandica shell carbonate |
title_sort |
high-resolution geochemical proxy record of ∆14c and d18o in the gulf of maine using arctica islandica shell carbonate |
publisher |
Iowa State University Digital Repository |
publishDate |
2012 |
url |
https://lib.dr.iastate.edu/etd/12566 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=3573&context=etd |
genre |
Arctica islandica North Atlantic |
genre_facet |
Arctica islandica North Atlantic |
op_source |
Graduate Theses and Dissertations |
op_relation |
https://lib.dr.iastate.edu/etd/12566 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=3573&context=etd |
_version_ |
1766353135967666176 |