SPINELLI Mariela Lorena
congresos y reuniones científicas
Short-term UVR exposure affects feeding in nauplii of copepods from coastal waters of Patagonia (Argentina)
Mar del Plata
Conferencia; CERF 2012 – The Changing Coastal & Estuarine Environment: A Comparative Approach; 2012
UVR (280-400 nm) may negatively affect how zooplankton capture, ingest,digest, and assimilate their food. Zooplankton may obtain protection bybioaccumulation of UV-absorbing compounds from their food preys. The aim ofthis study was to evaluate whether the ingestion rate of copepod nauplii fed onHeterocapsa sp (H-) and Heterocapsa sp rich in UV-absorbing compounds (H+)are affected by UVR and subsequent light regime. Nauplii were collected insurface waters and fed (‘Feeding 1’), for 24 h at in situ temperature, on either(H-) or (H+). Then they were exposed to UVR and PAR (400-700 nm)treatments for 4 h (irradiances of 0.7, 48 and 164 W m-2 for UVB, UVA andPAR, respectively). After the exposure, nauplii were incubated either in dark orunder PAR (photoperiod) the same food as ‘feeding 1’ during 24 h (‘Feeding 2’).Samples were fixed with Lugol for cell counting to estimate the ingestion rate(cells number/ nauplii/ h). In Feeding 1, ingestion rates were similar with bothdiets (367 and 474 cells/nauplii /h respectively; P>0.05). In Feeding 2, with bothdiets, nauplii receiving dark UVR treatment did not feed, and in photoperiodtheir ingestion rate was significantly lower in those exposed to UVR than in thePAR treatment (p <0.05). We observed that the ingestion rate decreased in naupliitreated with UVR. Moreover, the results suggest that the photorepair may be animportant strategy in this group of larvae. These results are importantconsidering that 1) the carbon flow from primary producers to primaryconsumers is greatly affected by the ingestion of food by herbivorouszooplankton and 2) the feeding and survival of nauplii larvae is a fundamentalaspect for the copepod populations; therefore a UVR-induced decrease in theingestion rate of nauplii may affect the amount of carbon and energy availableto other trophic levels.