Vulnerability of Patagonian planktonic copepods to fluctuations in temperature and UVR

PATRICIA E., GARCIA; DIEGUEZ, M. C.

CRUSTACEANA

BRILL ACADEMIC PUBLISHERS

Lugar: Leiden; Año: 2014 vol. 83 p. 291 - 304

0011-216X

The aim of this investigation is to address the impact of fluctuations in temperature andultraviolet radiation (UVR) on three species of South American copepods, Boeckellaantiqua, B. gracilis and B. brevicaudata. Due to their restricted distribution to highlatitude lakes of South America and to mountain lakes in the Andes, these copepodsare considered cold stenotherm. The forecasted scenarios for climate change inSouthern South America anticipate raising temperature and UVR levels with thepotential to impact different ecosystems, and particularly, high altitude and latitudelakes and their cold adapted biota, such as those in Patagonia. Laboratoryexperiments were set up to analyse: (i) the effect of temperature and, (ii) the combinedeffect of temperature (5, 8, 12, 16, 20°C) and the dose of UV-B radiation (61, 194 and324 J m-2) on copepod mortality. Experiments consisted of 10 day and 2 dayincubations, respectively. The results showed that temperature is a limiting factor for B.brevicaudata that did not survive above 12°C. B. antiqua and B. gracilis withstood thetemperature range; however, their mortality was higher between 12°C and 16°C. Thesecond set of experiments showed that the survivorship of the three copepod speciesdepend on the UV-B dose applied, with higher mortality at the highest dose. Thetreatments combining the higher temperatures of the range and the highest UV-B doseincreased copepod mortality. Overall, at least one Boeckella species showed an acutesensitivity to increasing temperature, and the three species studied withstood theexposure to UV-B. The tolerance levels observed in this study reflect the specificadaptation of the copepods to conditions ranging from temperate to cold, and the highexposure to elevated solar radiation prevailing in their natural environments.