Sp. Madon et al., IN-SITU ESTIMATION OF ZEBRA MUSSEL METABOLIC RATES USING THE ELECTRON-TRANSPORT SYSTEM (ETS) ASSAY, Journal of shellfish research, 17(1), 1998, pp. 195-203
We used the electron transport system (ETS) assay to estimate in situ
respiration rates of zebra mussels. Laboratory studies revealed a line
ar relationship (r(2) = 0.93) between respiration rates and ETS enzyme
activity across all sizes of mussels tested (10-30 mm shell length; 0
.03-0.55 g tissue wet mass); ETS activity and respiration rates (mg 0,
mussel(-1) h(-1)) were both strongly and similarly related to soft-ti
ssue wet mass (r(2) > 0.92). Zebra mussels used only 6-7% of their ETS
for respiration (R); this average R/ETS ratio of 0.06-0.07 did not va
ry with mussel sizes. Independent statistical tests revealed that the
ETS-respiration rate relationship provided accurate estimates of respi
ration rates in zebra mussel individuals and populations. After calibr
ation of the ETS-respiration rare ratio, we used the relationship to e
stimate in situ oxygen demand by zebra mussel populations in the Upper
Mississippi River. There was a strong relationship between oxygen dem
and (mg O-2 m(-2) h(-1)) and zebra mussel density per square meter(r(2
) = 0.93. p < 0.0001). A zebra mussel population of approximately 23,0
00 individuals/m(2) is estimated to have an oxygen demand of 9.41 g O-
2 m(-2) d(-1), twice as high as that of highly enriched organic deposi
ts. Dense populations of zebra mussels are expected to exert strong de
mands on the oxygen resources of large rivers.