Environmental Engineering Reference
In-Depth Information
UV-A deleterious effects on aquatic organisms (Alonso Rodriguez et al.
2000, Browman et al. 2000, Ban et al. 2007).
UV-B radiation cause negative effects on various copepods species
(Karanas et al. 1979, Naganuma et al. 1997, Lacuna and Uye 2001). For
instance, experiments on
Acartia clausii
, a dominant copepod of coastal
and estuarine zooplankton community of the Northern Hemisphere,
revealed that UV-B affects both survival and reproduction rate of this
copepod (Karanas et al. 1979). The embryogenesis, survival of nauplii
and copepodites, feeding and egg production of adult
Acartia omorii
were
affected by artifi cial UV-B radiation. Moreover, the relatively high UV-B
exposure of eggs produced malformations of the nauplii (Lacuna and Uye
2001). In contrast, no harmful effect was detected under UV-A radiation
on this copepod (Lacuna and Uye 2001). Similar results of the UV-B
effects were observed on
Calanus sinicus
(Naganuma et al. 1997),
Calanus
fi nmarchicus
(Kouwenberg et al. 1999b) and
Sinocalanus tenellus
(Lacuna
and Uye 2000).
Negative effects of UV radiation on
C. fi nmarchicus
eggs have been
observed on fi eld experiments in the Estuary and the Gulf of St. Lawrence
(Alonso Rodriguez et al. 2000, Browman et al. 2000). The results suggested
that under the current levels of exposure, UV-B radiation is negatively
affecting
C. fi nmarchicus
eggs occurring in the upper layers of the ocean.
Furthermore, the hatching of eggs of
C. fi nmarchicus
exposed to UV-B and
UV-A was not different from that exposed only to UV-A. In contrast, UV-A
radiation seemed to be more detrimental on embryos of
C. fi nmarchicus
than
UV-B (Alonso Rodriguez et al. 2000, Browman et al. 2000). In an analogous
experiment, embryos of the Atlantic cod
Gadus morhua
exposed to UV-B
radiation exhibited a higher rate of mortality, presumably as a result of
DNA damage (Browman et al. 2000). In accordance, both calyptosis larvae
of
E. superba
and copepodites of
Calanoides acutus
and
Calanus propinquus
were susceptible to natural UV-B and UV-A (Ban et al. 2007). The effects
of UV-B radiation in different stages of these species were related to DNA
damage, while the UV-A radiation effects consisted of the formation of
hydroxyl radicals that accumulated in cells and caused oxidative damage
to membrane lipid and other cellular components (Beer et al. 1993). The
modifi cation of the DNA structure is at the base of all detrimental UV effects
in living organisms. The DNA damage generated by UV-B is produced by
the accumulation of cyclobutane pyrimidine dimers (CPDs) (Malloy et al.
1997). High levels of DNA damage detected in eggs and larvae of icefi sh
Chaenocephalus aceratus
have been attributed to UV-B irradiance, and CPD
content was correlated with the daily incidence of UV-B irradiance (Malloy
et al. 1997). Additionally, Brownam et al. (2003) observed that the copepod
C. fi nmarchicus
was much more susceptible to CPD formation than the cod
