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A study of Mg/Ca in benthic foramini-fera sampled across a large salinity gradient

Gabrielsson, Johan LU (2014) In Dissertations in Geology at Lund University GEOR02 20142
Department of Geology
Abstract
Multiple studies have found a link between Mg/Ca in foraminifera and various environmental factors (e.g Billups and Schrag, 2002; Dissard et al., 2010; Ferguson et al., 2008). This has allowed for paleoenvi-ronmental reconstructions based on Mg/Ca in foraminifera to be made. My thesis has intended to find the influence of temperature and salinity on Mg/Ca in three species and one benthic Genus of foraminifera (Bulimina.marginata, Globobulimina.turgida, Nonionellina.labradorica and Elphidium spp.). The foraminifera were collected from eight modern coretops close to the Swedish coast from Hanö bay in the Baltic Sea to Skagerrak. In order to examine the accuracy of the produced calibration equations, an attempt was made to reconstruct... (More)
Multiple studies have found a link between Mg/Ca in foraminifera and various environmental factors (e.g Billups and Schrag, 2002; Dissard et al., 2010; Ferguson et al., 2008). This has allowed for paleoenvi-ronmental reconstructions based on Mg/Ca in foraminifera to be made. My thesis has intended to find the influence of temperature and salinity on Mg/Ca in three species and one benthic Genus of foraminifera (Bulimina.marginata, Globobulimina.turgida, Nonionellina.labradorica and Elphidium spp.). The foraminifera were collected from eight modern coretops close to the Swedish coast from Hanö bay in the Baltic Sea to Skagerrak. In order to examine the accuracy of the produced calibration equations, an attempt was made to reconstruct temperature and salinity condit-ions in Lomma Bay. This was done by analysing the Mg/Ca in B.marginata and Elphidium spp. specimens from a core retrieved there and using the calibration equations to estimate past temperature and salinity.
The produced calibration equations showed R2 values for temperature ranging from 0.1 to 0.5 and from 0.05 to 0.99 for salinity. R2 values from a multiple regression anlysis conducted on the data ranges from 0.11 to 1.00. The small number of data points resulted in low p-values for all examined taxa, this in combination with a lack of correspon-dance between estimated values for Lomma Bay temperature and salinity and actual modern values indicates that the calibration equations are not reliable.
Large variations in Mg/Ca are observed ranging from 0.5 mmol/mol (G.turgida) to 1.6 mmol/mol (N.labradorica). Theese large variations occur over narrow gradients in temperature and salinity indicating that theese variations are mainly due to vital effects.
My thesis contributes to increased knowledge of the distribution of Mg/Ca within benthic species of foraminifera and will contribute to increased knowledge of how Mg/Ca varies due to temperature and salinity in estuarine areas . (Less)
Popular Abstract (Swedish)
Ett flertal studier har funnit ett samband mellan Mg/Ca i foraminiferer och olika miljö-faktorer såsom temperatur (e.g Billups and Schrag, 2002; Dissard et al., 2010; Ferguson et al., 2008). Detta har möjliggjort paleomiljörekonstruktioner baserade på Mg/Ca i foraminiferer. Detta examensarbete har haft som mål att undersöka påverkan av temperatur och salinitet på Mg/Ca i tre arter och ett släkte av bottenlevande foraminife-rer (Bulimina.marginata, Globobulimina.turgida, Nonionellina.labradorica och Elphidium spp.). Foraminifererna samlades in från åtta moderna kärntoppar i en transekt från Hanöbukten i Östersjön till Skagerrak. För att under-söka precisionen på kalibreringskurvorna som producerats, gjordes ett försök att rekonstruera... (More)
Ett flertal studier har funnit ett samband mellan Mg/Ca i foraminiferer och olika miljö-faktorer såsom temperatur (e.g Billups and Schrag, 2002; Dissard et al., 2010; Ferguson et al., 2008). Detta har möjliggjort paleomiljörekonstruktioner baserade på Mg/Ca i foraminiferer. Detta examensarbete har haft som mål att undersöka påverkan av temperatur och salinitet på Mg/Ca i tre arter och ett släkte av bottenlevande foraminife-rer (Bulimina.marginata, Globobulimina.turgida, Nonionellina.labradorica och Elphidium spp.). Foraminifererna samlades in från åtta moderna kärntoppar i en transekt från Hanöbukten i Östersjön till Skagerrak. För att under-söka precisionen på kalibreringskurvorna som producerats, gjordes ett försök att rekonstruera temperatur och sali-nitetsförhållanden i Lommabukten på svenska västkusten. Detta gjordes genom att analysera Mg/Ca i B.marginata och Elphidium spp. Prover- tagna från en kärna provtagen i Lommabukten. De producerade kalibreringsekvationer-na användes sedan för att uppskatta tidigare temperaturer och salinitetsnivåer.
De producerade kalibreringsekvationerna uppvisade R2 värden för temperatur uppskattningarna på mellan 0,1 och 0,5. För salinitet uppvisades R2 värden på mellan 0.05 och 0.99. R2 värden på från multipel regressionsanalys uppvi-sade värden mellan 0,11 och 1,00. Det låga antalet datapunkter resulterade i låga p-värden för alla undersökta släk-ten. Detta, i kombination med bristen på överenstämmelse mellan de uppskattade värdena för temperatur och sali-nitet i Lommabukten, och de där uppmäta moderna värdena, indikerar att kalibreringsekvationerna inte är pålitliga.
Stora variationer i Mg/Ca inom de undersökta arterna kan observeras på mellan 0,5 mmol/mol (G. turgida) till 1.6 mmol/mol (N. labradorica). Dessa stora variationer har observerats över låga gradienter i temperatur och salinitet vilket indikerar att dessa variationer huvudsakligen beror på vitala effekter.
Mitt arbete bidrar till ökad kunskap om hur Mg/Ca fördelas mellan olika bottenlevande foraminiferarter och kom-mer att bidra till ökad förståelse om hur Mg/Ca varierar med avseende på temperatur och salthalt i kustnära områ-den. (Less)
Please use this url to cite or link to this publication:
author
Gabrielsson, Johan LU
supervisor
organization
alternative title
En studie över Mg/Ca i bentiska foraminiferer provtagna över en stor salinitetsgradient
course
GEOR02 20142
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Foraminifera, Mg/Ca, temperature, salinity, calibration equations
publication/series
Dissertations in Geology at Lund University
report number
422
language
English
id
5031779
date added to LUP
2015-01-29 12:52:26
date last changed
2023-08-16 13:05:58
@misc{5031779,
  abstract     = {{Multiple studies have found a link between Mg/Ca in foraminifera and various environmental factors (e.g Billups and Schrag, 2002; Dissard et al., 2010; Ferguson et al., 2008). This has allowed for paleoenvi-ronmental reconstructions based on Mg/Ca in foraminifera to be made. My thesis has intended to find the influence of temperature and salinity on Mg/Ca in three species and one benthic Genus of foraminifera (Bulimina.marginata, Globobulimina.turgida, Nonionellina.labradorica and Elphidium spp.). The foraminifera were collected from eight modern coretops close to the Swedish coast from Hanö bay in the Baltic Sea to Skagerrak. In order to examine the accuracy of the produced calibration equations, an attempt was made to reconstruct temperature and salinity condit-ions in Lomma Bay. This was done by analysing the Mg/Ca in B.marginata and Elphidium spp. specimens from a core retrieved there and using the calibration equations to estimate past temperature and salinity.
The produced calibration equations showed R2 values for temperature ranging from 0.1 to 0.5 and from 0.05 to 0.99 for salinity. R2 values from a multiple regression anlysis conducted on the data ranges from 0.11 to 1.00. The small number of data points resulted in low p-values for all examined taxa, this in combination with a lack of correspon-dance between estimated values for Lomma Bay temperature and salinity and actual modern values indicates that the calibration equations are not reliable.
Large variations in Mg/Ca are observed ranging from 0.5 mmol/mol (G.turgida) to 1.6 mmol/mol (N.labradorica). Theese large variations occur over narrow gradients in temperature and salinity indicating that theese variations are mainly due to vital effects.
My thesis contributes to increased knowledge of the distribution of Mg/Ca within benthic species of foraminifera and will contribute to increased knowledge of how Mg/Ca varies due to temperature and salinity in estuarine areas .}},
  author       = {{Gabrielsson, Johan}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{Dissertations in Geology at Lund University}},
  title        = {{A study of Mg/Ca in benthic foramini-fera sampled across a large salinity gradient}},
  year         = {{2014}},
}