Impact of climate change on Antarctic krill

Elevated UV radiation

Stratospheric ozone over Antarctica is predicted to

recover from near-depletion during the second half

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Mar Ecol Prog Ser 458: 1–19, 2012

of the current century (around 2060). As long as the

ozone layer has not fully recovered, UV radiation is

likely to act as an additional environmental stressor

on krill and Antarctic ecosystems. Over the last few

decades there has been a considerable zonal asym-

metry in total ozone distribution over Antarctica due

to planetary waves in the polar stratosphere (Evtu-

shevsky et al. 2008). In Antarctic spring (September

to November), the minimum of the quasi-stationary

wave (QSW) in total ozone distribution is continu-

ously located over the Antarctic Peninsula and

 Weddell Sea area, where the major part of the krill

population resides. The quasi-stationary minimum in

ozone distribution over the northern Weddell Sea

area can increase sea surface UV irradiation in com-

parison to the Ross Sea and East Antarctica, where

low UV radiation exists in spring.

Elevated UV radiation is known to impact marine

organisms (Karentz 1991, Naganobu et al. 1999, Kar-

entz & Bosch 2001). The direct impact of UV-B on the

krill population can occur through genetic damage

(Jarman et al. 1999, Dahms et al. 2011), physiological

effects (Newman et al. 1999, 2000) or through behav-

ioural reactions (Newman et al. 2003). Indirect effects

can arise through declines in primary productivity

caused by increased UV radiation and changes in the

structure of food webs.