F. Mosslacher, Sensitivity of groundwater and surface water crustaceans to chemical pollutants and hypoxia: implications for pollution management, ARCH HYDROB, 149(1), 2000, pp. 51-66
In order to test the hypothesis that groundwater organisms are more sensiti
ve to stressors than surface water organisms, this study compares the respo
nses of surface and groundwater isopods, cyclopoid copepods and ostracods t
o inorganic chemicals (potassium chloride and potassium nitrate) and low ox
ygen concentration (10 % oxygen saturation, hypoxia) in laboratory experime
nts. Isopods displayed the highest sensitivity to the chemicals (LC50 value
s for KCl: Proasellus slavus vindobonensis = 285 mg/l, and Asellus aquaticu
s = 355 mg/l), ostracods turned out to be most tolerant (LC50 values for KC
l: Fabaeformiscandona wegelini = 1932 mg/l, and Pseudocandona sp. = 2018 mg
/l). Comparing the response of species within one taxonomic group (isopods,
copepods, and ostracods), the exclusive groundwater species (stygobites) w
ere more sensitive to the chemicals than closely related surface water spec
ies (see above). The stygobite species displayed no differences between the
metabolism measured under normoxic and hypoxic conditions. A copepod, Acan
thocyclops vernalis, collected in a hypoxic groundwater habitat, showed sma
ll metabolic differences (i.e., the metabolic rate measured in hypoxia amou
nted to 61.8 +/- 5.5 % of the metabolism in normoxia), compared to a copepo
d, Diacylops bicuspidatus, collected in a normoxic groundwater habitat (27.
3 +/- 6.9 %). Due to the low difference between the metabolic rates, the st
ygobite organisms and A. vernalis were best adapted to low oxygen concentra
tions among the tested species.
The hypothesis was supported by this study. The high sensitivity of the gro
und-water crustaceans to the chemical stressors suggests that existing grou
ndwater quality criteria are insufficient to protect the groundwater biota
and ecosystem, and further ecotoxicological studies with groundwater organi
sms are required.