Department of Estuarine and Ocean Sciences MS Defense by Nathalie Danielle Staiger
When: Monday,
September 9, 2019
10:30 AM
-
11:30 AM
Where: > See description for location
Description: The School for Marine Science and Technology
Department of Estuarine and Ocean Sciences
MS Defense Announcement
"Seasonal and Intra-Annual Variability in Shell Chemistry of Planktonic Foraminifera Globigerionoides rubber (white) Morphotypes in the Sargasso Sea: 1998-2020"
by
Nathalie Danielle Staiger
Advisor
Cindy Pilskaln
Committee Members:
Dr. Mark Altabet, SMAST
Dr. Maureen Conte, Marine Biological Labs and Bermuda Inst. of Ocean Sciences
Monday, September 9, 2019
10:30 am
SMAST East, Room 101
836 S. Rodney French Blvd, New Bedford
Abstract:
Planktonic foraminifera are calcifying protists used extensively as proxies in reconstructing paleoenvironmental conditions during calcification, the ambient seawater’s isotopic signatures are recorded in their tests. Test compositions of oxygen and carbon isotopes reflect the seawater temperature and carbonate ion concentration present during calcification, respectively. Globigerinoides ruber (white) is a highly successful planktonic, symbiont-bearing species, dwelling in tropical, subtropical, and transitional waters worldwide. Its vast distribution and shallow calcification depth (0-50 m) facilitate its use for the global analysis of surface mixed layer depth chemistry. Some studies comparing the species’ morphotypes (sensu stricto and sensu lato) have identified variations in shell isotopic composition, suggesting potential differences in habitat depth among morphotypes and stressing a need to separate the morphotypes for analysis. However, studies from other regions have contradicted these results, asserting that depending upon the location and hydrographic dynamics at that study site, separation of morphotypes is not necessary. Previous studies have compared the isotopic composition of morphotype G. ruber (w) in the Pacific Ocean, China Sea, Indian Ocean, and Gulf of Mexico. The chromotype Globigerinoides ruber (pink), which lacks morphotypes, has been examined in the Sargasso Sea. To make best use of G. ruber (w) as a global proxy in climate reconstructions, it is imperative to understand the species’ life habits in all environments and impacts on shell composition of changes in ambient water chemistry. The study uses preserved shells of Sargasso Sea G. ruber (w) from 1998-2010. Archived Oceanic Flux Program (OFP) sediment trap samples were analyzed for stable carbon and oxygen isotope composition. Bermuda Atlantic Time-Series (BATS) hydrographic data were used to determine concurrent ambient water chemistry. Use of OFP samples and BATS data allows us to determine if G. ruber (w) shell chemistry significantly records surface [CO32-] and establishes if the morphotypes accurately (1) reflect seasonal variability of stable isotopes in the Sargasso Sea, (2) record surface carbonate ion concentration [CO32-], and (3) if there is a significant relationship between [CO32-] and shell density.
For additional information, please contact Sue Silva at s1silva@umassd.edu.
Department of Estuarine and Ocean Sciences
MS Defense Announcement
"Seasonal and Intra-Annual Variability in Shell Chemistry of Planktonic Foraminifera Globigerionoides rubber (white) Morphotypes in the Sargasso Sea: 1998-2020"
by
Nathalie Danielle Staiger
Advisor
Cindy Pilskaln
Committee Members:
Dr. Mark Altabet, SMAST
Dr. Maureen Conte, Marine Biological Labs and Bermuda Inst. of Ocean Sciences
Monday, September 9, 2019
10:30 am
SMAST East, Room 101
836 S. Rodney French Blvd, New Bedford
Abstract:
Planktonic foraminifera are calcifying protists used extensively as proxies in reconstructing paleoenvironmental conditions during calcification, the ambient seawater’s isotopic signatures are recorded in their tests. Test compositions of oxygen and carbon isotopes reflect the seawater temperature and carbonate ion concentration present during calcification, respectively. Globigerinoides ruber (white) is a highly successful planktonic, symbiont-bearing species, dwelling in tropical, subtropical, and transitional waters worldwide. Its vast distribution and shallow calcification depth (0-50 m) facilitate its use for the global analysis of surface mixed layer depth chemistry. Some studies comparing the species’ morphotypes (sensu stricto and sensu lato) have identified variations in shell isotopic composition, suggesting potential differences in habitat depth among morphotypes and stressing a need to separate the morphotypes for analysis. However, studies from other regions have contradicted these results, asserting that depending upon the location and hydrographic dynamics at that study site, separation of morphotypes is not necessary. Previous studies have compared the isotopic composition of morphotype G. ruber (w) in the Pacific Ocean, China Sea, Indian Ocean, and Gulf of Mexico. The chromotype Globigerinoides ruber (pink), which lacks morphotypes, has been examined in the Sargasso Sea. To make best use of G. ruber (w) as a global proxy in climate reconstructions, it is imperative to understand the species’ life habits in all environments and impacts on shell composition of changes in ambient water chemistry. The study uses preserved shells of Sargasso Sea G. ruber (w) from 1998-2010. Archived Oceanic Flux Program (OFP) sediment trap samples were analyzed for stable carbon and oxygen isotope composition. Bermuda Atlantic Time-Series (BATS) hydrographic data were used to determine concurrent ambient water chemistry. Use of OFP samples and BATS data allows us to determine if G. ruber (w) shell chemistry significantly records surface [CO32-] and establishes if the morphotypes accurately (1) reflect seasonal variability of stable isotopes in the Sargasso Sea, (2) record surface carbonate ion concentration [CO32-], and (3) if there is a significant relationship between [CO32-] and shell density.
For additional information, please contact Sue Silva at s1silva@umassd.edu.
Contact: > See Description for contact information
Topical Areas: School for Marine Sciences and Technology, SMAST Seminar Series