Lipid biomarker and stable isotopic profiles through Early-Middle Ordovician carbonates from Spitsbergen, Norway

Carina Lee, Gordon D. Love, Melanie J. Hopkins, Björn Kröger, Franziska Franeck, Seth Finnegan

Research output: Contribution to journalArticleScientificpeer-review

Abstract

One of the most dramatic episodes of sustained diversification of marine ecosystems in Earth history took place during the Early to Middle Ordovician Period. Changes in climate, oceanographic conditions, and trophic structure are hypothesised to have been major drivers of these biotic events, but relatively little is known about the composition and stability of marine microbial communities controlling biogeochemical cycles at the base of the food chain. This study examines well-preserved, carbonate-rich strata spanning the Tremadocian through Upper Dapingian stages from the Oslobreen Group in Spitsbergen, Norway. Abundant bacterial lipid markers (elevated hopane/sterane ratios, average = 4.8; maximum of 13.1), detection of Chlorobi markers in organic-rich strata, and bulk nitrogen isotopes (delta N-15(total)) averaging 0 to -1 parts per thousand for the open marine facies, suggest episodes of water column redox-stratification and that primary production was likely limited by fixed nitrogen availability in the photic zone. Near absence of the C-30 sterane marine algal biomarker, 24-n-propylcholestane (24-npc), in most samples supports and extends the previously observed hiatus of 24-npc in Early Paleozoic (Late Cambrian to Early Silurian) marine environments. Very high abundances of 3 beta-methylhopanes (average = 9.9%; maximum of 16.8%), extends this biomarker characteristic to Early Ordovician strata for the first time and may reflect enhanced and sustained marine methane cycling during this interval of fluctuating climatic and low sulfate marine conditions. Olenid trilobite fossils are prominent in strata deposited during an interval of marine transgression with biomarker evidence for episodic euxinia/anoxia extending into the photic zone of the water column. (C) 2019 Elsevier Ltd. All rights reserved.

Original languageEnglish
JournalOrganic Geochemistry
Volume131
Pages (from-to)5-18
Number of pages14
ISSN0146-6380
DOIs
Publication statusPublished - May 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 2-METHYLHOPANOID PRODUCTION
  • BIODIVERSIFICATION EVENT
  • Carbon isotopes
  • Early Ordovician
  • GLOEOCAPSOMORPHA-PRISCA ZALESSKY
  • GOBE
  • MICROBIAL COMMUNITY STRUCTURE
  • MOLECULAR INDICATORS
  • Methane cycling
  • Middle Ordovician
  • NY-FRIESLAND
  • Nitrogen isotopes
  • ORGANIC-MATTER
  • REDOX CONDITIONS
  • SOURCE ROCKS
  • TARIM BASIN
  • 1171 Geosciences

Cite this

Lee, Carina ; Love, Gordon D. ; Hopkins, Melanie J. ; Kröger, Björn ; Franeck, Franziska ; Finnegan, Seth. / Lipid biomarker and stable isotopic profiles through Early-Middle Ordovician carbonates from Spitsbergen, Norway. In: Organic Geochemistry. 2019 ; Vol. 131. pp. 5-18.
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abstract = "One of the most dramatic episodes of sustained diversification of marine ecosystems in Earth history took place during the Early to Middle Ordovician Period. Changes in climate, oceanographic conditions, and trophic structure are hypothesised to have been major drivers of these biotic events, but relatively little is known about the composition and stability of marine microbial communities controlling biogeochemical cycles at the base of the food chain. This study examines well-preserved, carbonate-rich strata spanning the Tremadocian through Upper Dapingian stages from the Oslobreen Group in Spitsbergen, Norway. Abundant bacterial lipid markers (elevated hopane/sterane ratios, average = 4.8; maximum of 13.1), detection of Chlorobi markers in organic-rich strata, and bulk nitrogen isotopes (delta N-15(total)) averaging 0 to -1 parts per thousand for the open marine facies, suggest episodes of water column redox-stratification and that primary production was likely limited by fixed nitrogen availability in the photic zone. Near absence of the C-30 sterane marine algal biomarker, 24-n-propylcholestane (24-npc), in most samples supports and extends the previously observed hiatus of 24-npc in Early Paleozoic (Late Cambrian to Early Silurian) marine environments. Very high abundances of 3 beta-methylhopanes (average = 9.9{\%}; maximum of 16.8{\%}), extends this biomarker characteristic to Early Ordovician strata for the first time and may reflect enhanced and sustained marine methane cycling during this interval of fluctuating climatic and low sulfate marine conditions. Olenid trilobite fossils are prominent in strata deposited during an interval of marine transgression with biomarker evidence for episodic euxinia/anoxia extending into the photic zone of the water column. (C) 2019 Elsevier Ltd. All rights reserved.",
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Lipid biomarker and stable isotopic profiles through Early-Middle Ordovician carbonates from Spitsbergen, Norway. / Lee, Carina; Love, Gordon D.; Hopkins, Melanie J.; Kröger, Björn; Franeck, Franziska; Finnegan, Seth.

In: Organic Geochemistry, Vol. 131, 05.2019, p. 5-18.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Lipid biomarker and stable isotopic profiles through Early-Middle Ordovician carbonates from Spitsbergen, Norway

AU - Lee, Carina

AU - Love, Gordon D.

AU - Hopkins, Melanie J.

AU - Kröger, Björn

AU - Franeck, Franziska

AU - Finnegan, Seth

PY - 2019/5

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N2 - One of the most dramatic episodes of sustained diversification of marine ecosystems in Earth history took place during the Early to Middle Ordovician Period. Changes in climate, oceanographic conditions, and trophic structure are hypothesised to have been major drivers of these biotic events, but relatively little is known about the composition and stability of marine microbial communities controlling biogeochemical cycles at the base of the food chain. This study examines well-preserved, carbonate-rich strata spanning the Tremadocian through Upper Dapingian stages from the Oslobreen Group in Spitsbergen, Norway. Abundant bacterial lipid markers (elevated hopane/sterane ratios, average = 4.8; maximum of 13.1), detection of Chlorobi markers in organic-rich strata, and bulk nitrogen isotopes (delta N-15(total)) averaging 0 to -1 parts per thousand for the open marine facies, suggest episodes of water column redox-stratification and that primary production was likely limited by fixed nitrogen availability in the photic zone. Near absence of the C-30 sterane marine algal biomarker, 24-n-propylcholestane (24-npc), in most samples supports and extends the previously observed hiatus of 24-npc in Early Paleozoic (Late Cambrian to Early Silurian) marine environments. Very high abundances of 3 beta-methylhopanes (average = 9.9%; maximum of 16.8%), extends this biomarker characteristic to Early Ordovician strata for the first time and may reflect enhanced and sustained marine methane cycling during this interval of fluctuating climatic and low sulfate marine conditions. Olenid trilobite fossils are prominent in strata deposited during an interval of marine transgression with biomarker evidence for episodic euxinia/anoxia extending into the photic zone of the water column. (C) 2019 Elsevier Ltd. All rights reserved.

AB - One of the most dramatic episodes of sustained diversification of marine ecosystems in Earth history took place during the Early to Middle Ordovician Period. Changes in climate, oceanographic conditions, and trophic structure are hypothesised to have been major drivers of these biotic events, but relatively little is known about the composition and stability of marine microbial communities controlling biogeochemical cycles at the base of the food chain. This study examines well-preserved, carbonate-rich strata spanning the Tremadocian through Upper Dapingian stages from the Oslobreen Group in Spitsbergen, Norway. Abundant bacterial lipid markers (elevated hopane/sterane ratios, average = 4.8; maximum of 13.1), detection of Chlorobi markers in organic-rich strata, and bulk nitrogen isotopes (delta N-15(total)) averaging 0 to -1 parts per thousand for the open marine facies, suggest episodes of water column redox-stratification and that primary production was likely limited by fixed nitrogen availability in the photic zone. Near absence of the C-30 sterane marine algal biomarker, 24-n-propylcholestane (24-npc), in most samples supports and extends the previously observed hiatus of 24-npc in Early Paleozoic (Late Cambrian to Early Silurian) marine environments. Very high abundances of 3 beta-methylhopanes (average = 9.9%; maximum of 16.8%), extends this biomarker characteristic to Early Ordovician strata for the first time and may reflect enhanced and sustained marine methane cycling during this interval of fluctuating climatic and low sulfate marine conditions. Olenid trilobite fossils are prominent in strata deposited during an interval of marine transgression with biomarker evidence for episodic euxinia/anoxia extending into the photic zone of the water column. (C) 2019 Elsevier Ltd. All rights reserved.

KW - 2-METHYLHOPANOID PRODUCTION

KW - BIODIVERSIFICATION EVENT

KW - Carbon isotopes

KW - Early Ordovician

KW - GLOEOCAPSOMORPHA-PRISCA ZALESSKY

KW - GOBE

KW - MICROBIAL COMMUNITY STRUCTURE

KW - MOLECULAR INDICATORS

KW - Methane cycling

KW - Middle Ordovician

KW - NY-FRIESLAND

KW - Nitrogen isotopes

KW - ORGANIC-MATTER

KW - REDOX CONDITIONS

KW - SOURCE ROCKS

KW - TARIM BASIN

KW - 1171 Geosciences

U2 - 10.1016/j.orggeochem.2019.02.008

DO - 10.1016/j.orggeochem.2019.02.008

M3 - Article

VL - 131

SP - 5

EP - 18

JO - Organic Geochemistry

JF - Organic Geochemistry

SN - 0146-6380

ER -