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Your search keyword '"Odontaster validus"' showing total 2 results
Start Over Descriptor "Odontaster validus" Journal marine environmental research
2 results on '"Odontaster validus"'

1. Experimental evidence of chemical defence mechanisms in Antarctic bryozoans

Author

Blanca Figuerola, Juan Moles, Conxita Avila, Cristina García-Aljaro, Laura Núñez-Pons, Anicet R. Blanch, Carlos Angulo-Preckler, and Laura Sala-Comorera

Subjects
0106 biological sciences, Antarctic Regions, Micrococcus, Odontaster validus, Aquatic Science, Oceanography, 010603 evolutionary biology, 01 natural sciences, Bryozoa, Intraspecific competition, Starfish, Paracoccus, Common species, Botany, Animals, Amphipoda, Biological Products, biology, 010604 marine biology & hydrobiology, Feeding Behavior, General Medicine, Marine invertebrates, biology.organism_classification, Adaptation, Physiological, Pollution, Anti-Bacterial Agents, Chemical ecology, Quorum Quenching, Predatory Behavior
Abstract

Bryozoans are among the most abundant and diverse members of the Antarctic benthos, however the role of bioactive metabolites in ecological interactions has been scarcely studied. To extend our knowledge about the chemical ecology of Antarctic bryozoans, crude ether extracts (EE) and butanol extracts (BE) obtained from two Antarctic common species (Cornucopina pectogemma and Nematoflustra flagellata), were tested for antibacterial and repellent activities. The extracts were screened for quorum quenching and antibacterial activities against four Antarctic bacterial strains (Bacillus aquimaris, Micrococcus sp., Oceanobacillus sp. and Paracoccus sp.). The Antarctic amphipod Cheirimedon femoratus and the sea star Odontaster validus were selected as sympatric predators to perform anti-predatory and substrate preference assays. No quorum quenching activity was detected in any of the extracts, while all EE exhibited growth inhibition towards at least one bacterium strain. Although the species were not repellent against the sea star, they caused repellence to the amphipods in both extracts, suggesting that defence activities against predation derive from both lipophilic and hydrophilic metabolites. In the substrate preference assays, one EE and one BE deriving from different specimens of the species C. pectogemma were active. This study reveals intraspecific variability of chemical defences and supports the fact that chemically mediated interactions are common in Antarctic bryozoans as means of protection against fouling and predation.

Published
2017
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2. Latitudinal changes in the trophic structure of benthic coastal food webs along the Antarctic Peninsula.

Author

Cardona, Luis, Lloret-Lloret, Elena, Moles, Juan, and Avila, Conxita

Subjects
*ISOTOPE shift, *STABLE isotopes, *WEBOMETRICS, *OFFSHORE structures, *PENINSULAS, *ALGAL blooms
Abstract

Stable isotopes of C and N have been used to assess the effect of the duration of the sea ice season on the structure of benthic, Antarctic coastal food webs. Samples of suspended particulate organic matter, macroalgae and macroinvertebrates were collected at five subtidal rocky sites across a latitudinal gradient along the western Antarctic Peninsula and among the South Shetland Islands. We tested the hypotheses that trophic positions of omnivores decrease, and food web structure becomes more redundant at higher latitudes. A latitudinal shift in the isotope baseline was detected for both δ 13C and δ 15N, but the trophic positions of macroinvertebrates and their relative positions along the δ 13C axis and were basically constant across sites, even after rescaling stable isotope ratios to account for shifts in the baseline. Although the northernmost and southernmost study sites differed significantly in most of the metrics of the food web structure, changes with latitude and the duration of the sea ice season were non-monotonic. Highly productive phytoplankton blooms during the ice-free season at Esperanza Bay and Rothera Point may explain the observed pattern, as they result in a massive supply of planktonic organic matter to the detritus bank in the seabed and, hence, shorten the C range and increase trophic redundancy. If this hypothesis is correct, the intensity of the summer phytoplankton bloom can be as relevant for the structure of the benthic marine food web as the duration of the sea ice season. • Stable isotopes of C and N have been used to assess the effect of the duration of the sea ice season on the structure of benthic, Antarctic coastal food webs. • We test the hypotheses that trophic positions of omnivores decrease, and food web structure becomes more redundant at higher latitudes. • A latitudinal shift in the isotope baseline was detected for both δ 13C and δ 15N, but the trophic positions of macroinvertebrates and their relative positions along the δ 13C axis and were basically constant across sites, even after rescaling stable isotope ratios to account for shifts in the baseline. • Although most of the metrics of the food web structure changed with latitude, site specific differences in intensity of the summer phytoplankton bloom can be as relevant for the structure of the benthic marine food web as the duration of the sea ice season. [ABSTRACT FROM AUTHOR]

Published
2021
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