Sea-level changes: molecular approaches to tell us the how and the when

TY - CONF

T1 - Sea-level changes: molecular approaches to tell us the how and the when

AU - Conti, Martina

AU - Robson, Harry Kenneth

AU - Milner, Nicky

AU - Keely, Brendan John

AU - Penkman, Kirsty Elizabeth Helena

AU - Wheeler, Lucy

AU - Demarchi, Beatrice

AU - Barlow, Natasha

AU - Bates, Martin

AU - Butler, Paul

AU - Reynolds, David

AU - Scourse, James

AU - Presslee, Samantha

PY - 2023/2/6

Y1 - 2023/2/6

N2 - The study of past sea-level changes is important to understand and predict future scenarios. Two key questions are: how was the paleoenvironment affected by sea-level changes, and when did the sea-level change occur? Sedimentological analyses and dating are key and in this work we explore geochemical ways of answering these questions. Targeted analysis of palaeontological evidence in sediment (e.g. pollen, foraminifera, microfossils) can help reconstruct the paleoenvironment, helping to provide data for rates of sea-level change. However, in some sequences microfossils are present only in low amounts, or are poorly preserved in the sediment, precluding detailed paleoenvironmental interpretation. In these cases, the molecular fossils trapped in the sediment matrix can help in the interpretation; these molecules tend to be well-preserved in sediments and can be biomarkers of specific groups of organisms that can be linked to palaeoenvironmental conditions via knowledge of their habitats. Using lipids and chlorophyll pigments, a more sensitive and accurate record of relative sea-level transgressions and their impact on palaeoclimate was recorded in Holocene and Mid-Pleistocene sediments.Alongside the identification of transgressive and regressive phases, dating is essential to contextualise the sea-level fluctuations. Where fossils are preserved, their intra-crystalline molecules have the potential to provide age information through amino acid geochronology (AAG). Previous studies on the marine gastropods Littorina and Nucella and foraminifera Ammonia and Neogloboquadrina pachyderma have provided relative dating spanning the Pleistocene period. In this work, we extend the aminostratigraphy to bivalves (Arctica islandica, Ostrea edulis and Cerastoderma edule), which have a more complicated shell microstructure. These case studies demonstrate the power of molecular approaches to reveal insights into past sea-level change.

AB - The study of past sea-level changes is important to understand and predict future scenarios. Two key questions are: how was the paleoenvironment affected by sea-level changes, and when did the sea-level change occur? Sedimentological analyses and dating are key and in this work we explore geochemical ways of answering these questions. Targeted analysis of palaeontological evidence in sediment (e.g. pollen, foraminifera, microfossils) can help reconstruct the paleoenvironment, helping to provide data for rates of sea-level change. However, in some sequences microfossils are present only in low amounts, or are poorly preserved in the sediment, precluding detailed paleoenvironmental interpretation. In these cases, the molecular fossils trapped in the sediment matrix can help in the interpretation; these molecules tend to be well-preserved in sediments and can be biomarkers of specific groups of organisms that can be linked to palaeoenvironmental conditions via knowledge of their habitats. Using lipids and chlorophyll pigments, a more sensitive and accurate record of relative sea-level transgressions and their impact on palaeoclimate was recorded in Holocene and Mid-Pleistocene sediments.Alongside the identification of transgressive and regressive phases, dating is essential to contextualise the sea-level fluctuations. Where fossils are preserved, their intra-crystalline molecules have the potential to provide age information through amino acid geochronology (AAG). Previous studies on the marine gastropods Littorina and Nucella and foraminifera Ammonia and Neogloboquadrina pachyderma have provided relative dating spanning the Pleistocene period. In this work, we extend the aminostratigraphy to bivalves (Arctica islandica, Ostrea edulis and Cerastoderma edule), which have a more complicated shell microstructure. These case studies demonstrate the power of molecular approaches to reveal insights into past sea-level change.

M3 - Poster

T2 - Sea Levels, Past, Present and Future

Y2 - 6 February 2023 through 7 February 2023

ER -