Impacts of UV radiation on respiration, ammonia excretion, and survival of copepods with different feeding habits

Abstract

Solar ultraviolet radiation (UVR) is known to harm aquatic organisms by damaging key molecules. Here, we showed that UV-A as well as UV-B affected differentially the respiration, ammonia excretion, and mortality of the copepods Pseudodiaptomus marinus (herbivorous) and Labidocera bipinnata (omnivorous). Adding UV-A (320-400 nm, 62.4 W m -2 ) to PAR (400-700 nm, 278 W m -2 ) decreased respiration by 10.2% in P. marinus and 46.1% in L. bipinnata, and additionally, the presence of UV-B (280-320 nm, 2.63 W m -2 ) further decreased it by 8.1 and 18.8%, respectively. The ammonia excretion of P. marinus was suppressed by 13.9% in 30 min exposures to PAR ? UV-A compared with those receiving PAR only; however, in the presence of UV-B, it decreased by 13.8% compared to the control. In L. bipinnata, exposure to PAR decreased the ammonia excretion by 33.4%, while the presence of UV-B caused additional suppression by 15.8%. The mortalities of both copepod species increased with prolonged duration under all radiation treatments. More carotenoids and UV-absorbing compounds were found in P. marinus than in L. bipinnata, which could have been responsible for the higher resistance of the former to solar UVR.

Copepod oxygen consumption along a salinity gradient

“…In the present study, low pH was generally associated with low salinity, and it is not possible to disentangle the effects of pH and salinity on the respiration rates. Physiological conditions, age, biomass, UV radiations and food conditions could also play an important role in respiration rate (Ma et al 2013). In order to mitigate the effect of physiological and food conditions, only ovigerous females were considered, and they were starved shortly before the experiments.…”

High Mortality of Red Sea Zooplankton under Ambient Solar Radiation

“…A recent meta-analysis demonstrated that crustaceans, a dominant component of zooplankton communities, are highly vulnerable to UV-B radiation [6] . Previous studies on planktonic (often neustonic) crustacean zooplankton showed that exposure to UV-B lead to behavioral [13] and physiological responses [14] – [16] ultimately affecting a range of fitness components [17] conducive to increased mortality [18] – [20] . Impacts of UV-B radiation is expected to be highest in tropical oligotrophic marine regions [11] , where high incident UV-B radiation combines with deep penetration to yield high UV-B doses to organisms inhabiting the mixed layer.…”