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TitleInvestigating the relationship between the elemental composition of coprolites and trophic level: a brief digest of Late Carboniferous coprolites from the Joggins Formation
 
AuthorBingham-Koslowski, N; Grey, M; Ehrman, J M; Pufahl, P
SourceThe Atlantic Geoscience Society (AGS), 47th Colloquium and Annual Meeting, program with abstracts/La Société Géoscientifique de l'Atlantique, 47th Colloquium and Annual Meeting, program with abstracts; 2021 p. 14 Open Access logo Open Access
LinksOnline - En ligne (complete volume - volume complet, PDF, 1.12 MB)
Image
Year2021
Alt SeriesNatural Resources Canada, Contribution Series 20200688
PublisherAtlantic Geoscience Society
MeetingThe Atlantic Geoscience Society-La Société Géoscientifique de l'Atlantique 47th Colloquium and Annual Meeting; February 5-6, 2021
Documentserial
Lang.English
Mediaon-line; digital
File formatpdf
ProvinceNova Scotia
NTS21H/09
AreaJoggins
Lat/Long WENS -64.4167 64.5000 45.7500 45.6667
Subjectspaleontology; mineralogy; Science and Technology; Nature and Environment; Upper Carboniferous; fossils; paleoenvironment; depositional environment; paleoecology; fossil morphology; scanning electron microscope analyses; spectroscopic analyses; sulphates; sulphides; Joggins Formation; Coprolites; Joggins Fossil Cliffs UNESCO World Heritage Site; Fish; Phanerozoic; Paleozoic; Carboniferous
ProgramGEM2: Geo-mapping for Energy and Minerals GEM Synthesis
Released2021 02 01
AbstractCoprolites offer insights into the diets of the animals that produced them, and thereby also provide a unique perspective of the paleoenvironments and paleoecosystems that existed during their deposition. Late Carboniferous fish coprolites are abundant in the Joggins Formation at the Joggins Fossil Cliffs UNESCO World Heritage Site (Joggins, Nova Scotia, Canada) and offer an opportunity to study the lesser-understood aquatic realm. The research presented here builds on a previous study that used hand samples and thin sections to classify coprolites into six morphotypes (conical, cylindrical, irregular, large, small, and spiral). Collectively, these morphotypes were interpreted to represent four trophic levels, and used to create a theoretical trophic pyramid for the Late Carboniferous aquatic realm at Joggins. This study hypothesizes that coprolites of differing trophic levels should show discrepancies in elemental composition due to dissimilar dietary requirements. If this hypothesis proves correct, chemical analyses of coprolites and the substrates in which they are found could provide valuable paleoenvironmental information and assist with the reconstruction of paleoecosystems and food webs throughout geological history.
Scanning electron microscopy - energy dispersive x-ray spectroscopy (SEM-EDS) was conducted on 42 coprolites, with representatives of each morphotype, to test whether elemental variation occurs between morphotypes reflecting variations in dietary requirements of the different trophic levels. SEM-EDS analysis detected the presence of three main compounds in both the coprolites and the surrounding substrate: FeS2, BaSO4, and ZnS. Of these, FeS2 and BaSO4 were detected more frequently than ZnS, and the sulphates/sulphides are not mutually exclusive of one another, with the rare sample containing all three and some samples being barren of any of these compounds. The sulphates/sulphides occur commonly (but not exclusively) near the boundaries of the coprolites, which could suggest a possible sulphur-based diagenetic crust. Furthermore, rare occurrences of zircon (substrate) and TiO2 (substrate and coprolite) were identified in some samples during the analysis.
Initial examination of the results has produced no obvious relationship between the presence of FeS2, BaSO4, and ZnS and morphotype/trophic level. Additional analyses (e.g., x-ray diffraction, carbon isotope analysis, ICPMS etc.) are needed to further delineate the elemental composition of coprolites, determine the origin of the various compounds detected, to establish the significance of the compounds, and to investigate how they are related, if at all, to morphotype and, by extension, trophic level.
Summary(Plain Language Summary, not published)
Coprolites (fossilized fecal matter), offer unique insights into the organisms that made them as well as the ancient environments in which they were deposited. Previous work on fish coprolites from the Late Carboniferous Joggins Formation in Nova Scotia classified the coprolites based on shape into 6 different types, and then related these shapes to trophic level. This study went a step further and hypothesized that if the different morphologies reflect different trophic levels, then there should be some detectable compositional differences in the coprolites due to different dietary requirements at different trophic levels. Forty-two coprolites, representing the six morphologies, were analyzed using scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS) and various amounts (from none to abundant) of FeS2, BaSO4, and ZnS were detected in both the substrate and within the coprolites themselves. Additionally, zircon and TiO2 were also identified in the samples. An initial examination of the analytical data has produced no obvious relationship between the presence of these sulphides and morphotype. More analyses are needed to determine the origin of the compounds, to establish their significance, and to investigate how they are related, if at all, to the morphology, and therefore trophic level.
GEOSCAN ID327976

 
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