Spatial distribution of benthic foraminiferal stable isotopes and dinocyst assemblages in surface sediments of the Trondheimsfjord, central Norway
Instrumental records from the Norwegian Sea and the Trondheimsfjord show evidence that changes of bottom water temperature and salinity in the fjord are linked to the salinity and temperature variability of the North Atlantic Current (NAC). Changes in primary productivity and salinity in the surface...
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ftcopernicus:oai:publications.copernicus.org:bg19052 2023-05-15T17:25:19+02:00 Spatial distribution of benthic foraminiferal stable isotopes and dinocyst assemblages in surface sediments of the Trondheimsfjord, central Norway Milzer, G. Giraudeau, J. Faust, J. Knies, J. Eynaud, F. Rühlemann, C. 2018-09-27 info:eu-repo/semantics/application/pdf https://doi.org/10.5194/bg-10-4433-2013 https://www.biogeosciences.net/10/4433/2013/ eng eng info:eu-repo/grantAgreement/EC/FP7/238111 doi:10.5194/bg-10-4433-2013 https://www.biogeosciences.net/10/4433/2013/ info:eu-repo/semantics/openAccess eISSN: 1726-4189 info:eu-repo/semantics/Text 2018 ftcopernicus https://doi.org/10.5194/bg-10-4433-2013 2019-12-24T09:55:16Z Instrumental records from the Norwegian Sea and the Trondheimsfjord show evidence that changes of bottom water temperature and salinity in the fjord are linked to the salinity and temperature variability of the North Atlantic Current (NAC). Changes in primary productivity and salinity in the surface and intermediate water masses in the Trondheimsfjord as well as the fjord sedimentary budget are mainly driven by changes in riverine input. In this study we use 59 surface sediment samples that are evenly distributed in the fjord to examine whether dinocyst assemblages and stable isotope ratios of benthic foraminifera reflect the present-day hydrology and can be used as palaeoceanographic proxies. In general, modern benthic δ 18 O and δ 13 C values decrease from the fjord entrance towards the fjord head with lowest values close to river inlets. This is essentially explained by gradients in the amounts of fresh water and terrigenous organic matter delivered from the hinterland. The distribution of benthic δ 13 C ratios across the fjord is controlled by the origin (terrigenous vs. marine) of organic matter, local topography-induced variability in organic matter flux at the water–sediment interface, and organic matter degradation. The dinocyst assemblages display the variations in hydrography with respect to the prevailing currents, the topography, and the freshwater and nutrient supply from rivers. The strength and depth of the pycnocline in the fjord strongly vary seasonally and thereby affect water mass characteristics as well as nutrient availability, temporally creating local conditions that explain the observed species distribution. Our results prove that dinocyst assemblages and benthic foraminiferal isotopes reliably mirror the complex fjord hydrology and can be used as proxies of Holocene climatic variability. Other/Unknown Material north atlantic current North Atlantic Norwegian Sea Copernicus Publications: E-Journals Norway Norwegian Sea Biogeosciences 10 7 4433 4448 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Instrumental records from the Norwegian Sea and the Trondheimsfjord show evidence that changes of bottom water temperature and salinity in the fjord are linked to the salinity and temperature variability of the North Atlantic Current (NAC). Changes in primary productivity and salinity in the surface and intermediate water masses in the Trondheimsfjord as well as the fjord sedimentary budget are mainly driven by changes in riverine input. In this study we use 59 surface sediment samples that are evenly distributed in the fjord to examine whether dinocyst assemblages and stable isotope ratios of benthic foraminifera reflect the present-day hydrology and can be used as palaeoceanographic proxies. In general, modern benthic δ 18 O and δ 13 C values decrease from the fjord entrance towards the fjord head with lowest values close to river inlets. This is essentially explained by gradients in the amounts of fresh water and terrigenous organic matter delivered from the hinterland. The distribution of benthic δ 13 C ratios across the fjord is controlled by the origin (terrigenous vs. marine) of organic matter, local topography-induced variability in organic matter flux at the water–sediment interface, and organic matter degradation. The dinocyst assemblages display the variations in hydrography with respect to the prevailing currents, the topography, and the freshwater and nutrient supply from rivers. The strength and depth of the pycnocline in the fjord strongly vary seasonally and thereby affect water mass characteristics as well as nutrient availability, temporally creating local conditions that explain the observed species distribution. Our results prove that dinocyst assemblages and benthic foraminiferal isotopes reliably mirror the complex fjord hydrology and can be used as proxies of Holocene climatic variability. |
format |
Other/Unknown Material |
author |
Milzer, G. Giraudeau, J. Faust, J. Knies, J. Eynaud, F. Rühlemann, C. |
spellingShingle |
Milzer, G. Giraudeau, J. Faust, J. Knies, J. Eynaud, F. Rühlemann, C. Spatial distribution of benthic foraminiferal stable isotopes and dinocyst assemblages in surface sediments of the Trondheimsfjord, central Norway |
author_facet |
Milzer, G. Giraudeau, J. Faust, J. Knies, J. Eynaud, F. Rühlemann, C. |
author_sort |
Milzer, G. |
title |
Spatial distribution of benthic foraminiferal stable isotopes and dinocyst assemblages in surface sediments of the Trondheimsfjord, central Norway |
title_short |
Spatial distribution of benthic foraminiferal stable isotopes and dinocyst assemblages in surface sediments of the Trondheimsfjord, central Norway |
title_full |
Spatial distribution of benthic foraminiferal stable isotopes and dinocyst assemblages in surface sediments of the Trondheimsfjord, central Norway |
title_fullStr |
Spatial distribution of benthic foraminiferal stable isotopes and dinocyst assemblages in surface sediments of the Trondheimsfjord, central Norway |
title_full_unstemmed |
Spatial distribution of benthic foraminiferal stable isotopes and dinocyst assemblages in surface sediments of the Trondheimsfjord, central Norway |
title_sort |
spatial distribution of benthic foraminiferal stable isotopes and dinocyst assemblages in surface sediments of the trondheimsfjord, central norway |
publishDate |
2018 |
url |
https://doi.org/10.5194/bg-10-4433-2013 https://www.biogeosciences.net/10/4433/2013/ |
geographic |
Norway Norwegian Sea |
geographic_facet |
Norway Norwegian Sea |
genre |
north atlantic current North Atlantic Norwegian Sea |
genre_facet |
north atlantic current North Atlantic Norwegian Sea |
op_source |
eISSN: 1726-4189 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/238111 doi:10.5194/bg-10-4433-2013 https://www.biogeosciences.net/10/4433/2013/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/bg-10-4433-2013 |
container_title |
Biogeosciences |
container_volume |
10 |
container_issue |
7 |
container_start_page |
4433 |
op_container_end_page |
4448 |
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1766116719962619904 |