Search results for "Chronology"
showing 10 items of 338 documents
Reference growth charts for Posidonia oceanica seagrass: An effective tool for assessing growth performance by age and depth
2016
Abstract Growth performance of rhizomes has become among the most used descriptors for monitoring Posidonia oceanica seagrass dynamics and population status. However, ability to detect any change of growth in space or in time is often confounded by natural age-induced decline. To overcome this problem, we have produced reference growth charts, which in other areas are universally recognized as a very powerful tool for comparing growth of living beings during their ontogeny. Reference growth charts involving different P. oceanica growth performance measures (speed of growth and primary production of rhizomes) have been built using proper statistical frameworks (GLMM, Segmented and Quantile R…
A review of transgenerational effects of ocean acidification on marine bivalves and their implications for sclerochronology
2020
Abstract Ocean acidification can negatively impact marine bivalves, especially their shell mineralization processes. Consequently, whether marine bivalves can rapidly acclimate and eventually adapt in an acidifying ocean is now increasingly receiving considerable attention. Projecting the fate of this vulnerable taxonomic group is also pivotal for the science of sclerochronology – the study which seeks to deduce records of past environmental changes and organismal life-history traits from various geochemical properties of periodically layered hard tissues (bivalve shells, corals, fish otoliths, etc.). In this review, we provide a concise overview of the long-term and transgenerational respo…
Sclerochronology - a highly versatile tool for mariculture and reconstruction of life history traits of the queen conch, Strombus gigas (Gastropoda)
2009
International audience; The queen conch, Strombus gigas, is an important fisheries resource in the Western Tropical Atlantic. In order to maintain harvesting success, improve fisheries management and contribute to mariculture pursuits, a detailed understanding of the life history traits of this species is required. Traditionally, this has been achieved by tedious and time-consuming long-term field observations. This study presents a highly versatile and rapid technique to estimate the timing and rate of shell growth based on sclerochronology. The Belizean S. gigas specimens (N = 2) from the offshore atoll, Glovers Reef, reached their final shell size (maximum shell height: 22.7 and 23.5 cm,…
Glycymeris pilosa (Bivalvia) - A high-potential geochemical archive of the environmental variability in the Adriatic Sea.
2019
Due to its outstanding longevity (decades), the shallow-water bivalve Glycmeris pilosa represents a prime target for sclerochronological research in the Mediterranean Sea. In the present study, we analyzed the microgrowth patterns and the stable carbon (δ13Cshell) and oxygen (δ18Oshell) isotopes of the outer shell layer of live-collected G. pilosa specimens from four different sites along the Croatian coast, middle Adriatic Sea. Combined analysis of shell growth patterns and temporally aligned δ18Oshell data indicated that the main growing season lasts from April to December, with fastest growth rates occurring during July and August when seawater temperatures exceeded 22 °C. Slow growth in…
Rodents and palaeogenetics: new perspectives.
2008
10 pages; Rodents are the most diversified mammalian order (484 extant genera including 2277 species), and they have a worldwide distribution. Palaeontological, morphological and molecular data have greatly helped to resolve their systematics and evolutionary history. However, some discrepancies remain between palaeontologists and molecular biologists. New techniques in molecular biology, and especially in palaeogenetics, allow us to have direct access to the hereditary material of extinct organisms, and they can compensate for some morphological limits. Unfortunately, few studies are dealing with rodent palaeogenetics, despite the amount of museum and fossil material available. Here, we re…
Statistical modelling and RCS detrending methods provide similar estimates of long-term trend in radial growth of common beech in north-eastern France
2011
International audience; Dendrochronological methods have greatly contributed to the documentation of past long-term trends in forest growth. These methods primarily focus on the high-frequency signals of tree ring chronologies. They require the removal of the ageing trend in tree growth, known as 'standardisation' or 'detrending', as a prerequisite to the estimation of such trends. Because the approach is sequential, it may however absorb part of the low-frequency historical signal. In this study, we investigate the effect of a sequential and a simultaneous estimation of the ageing trend on the chronology of growth. We formerly developed a method to estimate historical changes in growth, in…
Resilience of the seagrass Posidonia oceanica following pulse-type disturbance.
2020
Understanding the response of species to disturbance and the ability to recover is crucial for preventing their potential collapse and ecosystem phase shifts. Explosive submarine activity, occurring in shallow volcanic vents, can be considered as a natural pulse disturbance, due to its suddenness and high intensity, potentially affecting nearby species and ecosystems. Here, we present the response of Posidonia oceanica, a long-lived seagrass, to an exceptional submarine volcanic explosion, which occurred in the Aeolian Archipelago (Italy, Mediterranean Sea) in 2002, and evaluate its resilience in terms of time required to recover after such a pulse event. The study was carried out in 2011 i…
8.2 ka event North Sea hydrography determined by bivalve shell stable isotope geochemistry.
2019
AbstractThe abrupt 8.2 ka cold event has been widely described from Greenland and North Atlantic records. However, its expression in shelf seas is poorly documented, and the temporal resolution of most marine records is inadequate to precisely determine the chronology of major events. A robust hydrographical reconstruction can provide an insight on climatic reaction times to perturbations to the Atlantic Meridional Overturning Circulation. Here we present an annually-resolved temperature and water column stratification reconstruction based on stable isotope geochemistry of Arctica islandica shells from the Fladen Ground (northern North Sea) temporally coherent with Greenland ice core record…
Carbon isotope stratigraphy, magnetostratigraphy, and 40Ar/39Ar age of the Cretaceous South Atlantic coast, Namibe Basin, Angola
2014
This publication results from Projecto PaleoAngola, an international cooperative research effort among the contributing authors and their institutions, funded by the National Geographic Society, the Petroleum Research Fund of the American Chemical Society, Sonangol E.P., Esso Angola, Fundacao Vida of Angola, LS Films, Maersk, Damco, Safmarine, ISEM at SMU, The Royal Dutch Embassy in Luanda, TAP Airlines, Royal Dutch Airlines, The Saurus Institute, and the Perot Museum of Nature and Science. JS was additionally funded by Yale University and the Alfred Kordelin Foundation. We dedicate this contribution to the late Kalunga Lima, our friend and colleague in Projecto PaleoAngola. We thank Margar…
Long-term summer temperature variations in the Pyrenees from detrended stable carbon isotopes
2015
Abstract Substantial effort has recently been put into the development of climate reconstructions from tree-ring stable carbon isotopes, though the interpretation of long-term trends retained in such timeseries remains challenging. Here we use detrended δ13C measurements in Pinus uncinata tree-rings, from the Spanish Pyrenees, to reconstruct decadal variations in summer temperature back to the 13th century. The June-August temperature signal of this reconstruction is attributed using decadally as well as annually resolved, 20th century δ13C data. Results indicate that late 20th century warming has not been unique within the context of the past 750 years. Our reconstruction contains greater …