Chemosensitizers of the multixenobiotic resistance in amorphous aggregates (marine snow): etiology of mass killing on the benthos in the Northern Adriatic?

Periodically appearing amorphous aggregates, 'marine snow', are formed in the sea and if settled as mars on the sea bottom cause death of benthic metazoans. Especially those animals are killed which are sessile filter feeders, e.g, sponges, mussels, or Anthozoa. The etiology of the toxic principle(s) is not yet well understood. Gel-like marine snow aggregates occurred in the Northern Adriatic during summer 1997. Samples of these aggregates were collected during the period July to September and the outer as well as the inner zones were analyzed for (i) cell toxicity, and (ii) chemosensitizing activity of the multixenobiotic resistance (MXR)mechanism. Organic extracts were prepared an…