Naslov
Multiproxy reconstruction of seawater temperature in the Bay of Brest using shells of dog cockles, Glycymeris glycymeris

Autori
Featherstone, Amy ; Peharda, Melita ; Schone, Bernd ; Butler, Paul ; Chauvaud, Laurent ; Thebault, Julien

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
4th International Sclerochronology Conference / Whitney, Nina - Iowa City (IA) : Iowa State University, 2016, 46-46

Skup
4th International Sclerochronology Conference

Mjesto i datum
Portland (OR), Sjedinjene Američke Države, 05.06.2016. - 09.06.2016

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
bivalve; sclerochronology; Glycymeris; stable isotopes; chronology

Sažetak
Since the end of the 20th century, global climate change has become a major focus of politicians and scientists worldwide, the consensus being that human activities are influencing environmental changes and affecting the Earth’s ecosystems. To establish the full extent of human influence, it is therefore necessary to reliably differentiate between natural variations in climate and anthropogenic influences. In order to do this, we must build a record of past long-term natural variability in the environment. In recent years bivalve mollusc shells have been successfully used as paleoenvironmental and paleoclimatic archives through the analysis of their growth increment patterns and their geochemical composition. Glycymeris glycymeris is a bivalve found in coarsegrained subtidal sediments, with a wide distribution from Cape Verde to Norway. Thanks to its remarkable longevity (up to 200 years in the northern part of its geographical distribution area), it has a strong potential for building chronologies extending over several centuries, making it a valuable resource for long-term climate reconstructions in temperate settings. Here, we developed a cross-dated chronology of over 30 years based on internal growth increments in G. glycymeris specimens collected both live and dead from the Bay of Brest, Brittany, France. The Standardised Growth Increment (SGI) chronology, developed from thirty-five individuals (average age 20 years), was found to be statistically robust (Expressed Population Signal (EPS)>0.85). In addition to growth increment analysis, eighteen specimens were investigated for their stable isotope composition. Aragonite samples were micromilled in early ontogeny growth increments of several specimens with overlapping lifespans, and subsequently analysed for their oxygen isotope composition. The continuous time-series of oxygen isotope ratios was then compared to in situ temperature and salinity data from the SOMLIT monitoring station, which was established in 1998, in order to calibrate and build a localised paleotemperature equation. This specific equation was then used to estimate sea surface temperatures in the Bay of Brest from 1969 to 2011. Overall, this study demonstrates that G. glycymeris can be used for decadal scale, high-resolution, reconstructions of past sea surface temperatures in the coastal waters of the Bay of Brest for periods before the availability of instrumental measurements.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Biologija

POVEZANOST RADA