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| Titel |
Sclerochronology - a highly versatile tool for mariculture and reconstruction of life history traits of the queen conch, \textit{Strombus gigas} (Gastropoda) |
| VerfasserIn |
Pascal Radermacher, Bernd R. Schöne, Eberhard Gischler, Wolfgang Oschmann, Julien Thébault, Jens Fiebig |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250042223
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| Zusammenfassung |
| The shell of the queen conch Strombus gigas provides a rapidly growing palaeoenvironmental
proxy archive, allowing the detailed reconstruction of important life-history traits such as
ontogeny, growth rate and growth seasonality. In this study, modern sclerochronological
methods are used to cross-date the palaeotemperatures derived from the shell with local sea
surface temperature (SST) records. The growth history of the shell suggests a bimodal
seasonality in growth, with the growing season confined to the interval between April and
November. In Glovers Reef, offshore Belize, the queen conch accreted shell carbonate at rates
of up to 6 mm day-1 during the spring (April-June) and autumn (September-November).
However a reduced period of growth occurred during the mid-summer months
(July-August). The shell growth patterns indicate a positive response to annual
seasonality with regards to precipitation. It seems likely that when precipitation levels are
high, food availability is increased as the result of nutrient input to the ecosystem in
correspondence with an increase in coastal runoff. Slow growth rates occur when
precipitation, and as a consequence riverine runoff, is low. The SST however appears to
influence growth only on a secondary level. Despite the bimodal growing season
and the winter cessation in growth, the growth rates reconstructed here from two
S. gigas shells are among the fastest yet reported for this species. The S. gigas
specimens from Belize reached their final shell height (of 22.7 and 23.5 cm in distance
between the apex and the siphonal notch) at the transition to adulthood in just 2
years.
The extremely rapid growth as observed in this species permits detailed, high-resolution
reconstructions of life-history traits where sub-daily resolutions can be achieved with
ease. The potential for future studies has yet to be further explored. Queen conch
sclerochronology provides an opportunity to recover extremely high-resolution
palaeotemperature records, which could be used to improve numeric climate models, where
the shells essentially function as mineralized buoys. The shell recorder may also help to
reveal changes in biogeochemical dynamics in benthic ecosystems on intra-seasonal
timescales in the fossil record. Furthermore, sclerochronology provides a rapid,
effective and highly versatile investigative strategy when compared to time- and
cost-consuming fieldwork for improving fisheries management and maricultural pursuits. |
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