Can UV radiation affect benthic deposit-feeders through biochemical alteration of food resources? An experimental study with juveniles of the benthic polychaete Eupolymnia nebulosa.

Abstract The growth, tentacledevelopment and feeding activity of the benthic polychaete Eupolymnia nebulosawere examined to determine whether UV might affect marine deposit-feeders indirectly through the modification of the nutritional quality of their resources. Since marine invertebrateshave higher nutritional requirements during the period following settlement, we tested the effect of UV-altered phytodetrituson freshly settled juveniles of E. nebulosa. Phytodetrituswas prepared from cultures of the diatom Skeletonema costatum either grown under or sheltered from UVB radiation. Sterol content of phytodetrituswas unmodified by UV radiation. Conversely, phytodetrituswas noticeably depleted in polyunsaturated fatty acids. Growthand tentacledevelopment of juveniles fed on altered phytodetrituswere reduced by 35% and 15% respectively, suggesting potential deficiencies in essential nutrients. In response to the lower quality of the phytodetritus, juveniles explored a wider area as they search for food, a strategy that could compensate for low food quality.