Silicon isotopes in Antarctic sponges: an interlaboratory comparison

Ecology and energetics of two Antarctic sponges.

Retention efficiencies, pumping and respiration rates of the two Antarctic sponge species Mycale acerata and Isodictya kerguelensis from Potter Cove, King George Island, were measured. None of the species reached a 100% retention efficiency at any given particle size. This is probably due to the sediment-laden environment in which the animals were dwelling. A less efficient retention decreases ...

Silicon isotopic fractionation in marine sponges: A new model for understanding silicon isotopic variations in sponges

Relevance of silicon isotopes to Si-nutrient utilization and Si-source assessment in Antarctic waters

[1] We analyzed dSi of dissolved silicate for eight water column profiles across the Southern Ocean (south of Australia in spring 2001) from the Seasonal Ice Zone (SIZ) north to the Subantarctic Zone (SAZ), including the first isotopic compositions measured for Si-depleted seawaters. All profiles display mixed layer enrichments in heavy Si isotopes relative to deep water in accordance with pref...

Interlaboratory comparison of simmondsin analysis

Eleven samples containing various amounts of simmondsin (S), simmondsin ferulate (SF), demethyl simmondsins (DMS) and didemethyl simmondsins (DDMS) were analyzed by five different laboratories. The samples were made from chromatographically pure simmondsin, animal feed formulations containing jojoba meal, defatted jojoba meal, water extracts of jojoba meal and combinations of these ingredients....

Bioactive volatile organic compounds from Antarctic (sponges) bacteria.

Antarctic bacteria represent a reservoir of unexplored biodiversity, which, in turn, might be correlated to the synthesis of still undescribed bioactive molecules, such as antibiotics. In this work we have further characterized a panel of four marine Antarctic bacteria able to inhibit the growth of human opportunistic multiresistant pathogenic bacteria belonging to the Burkholderia cepacia comp...