Je. Petersen et Cc. Chen, A method for measuring depth-integrated community metabolism in experimental planktonic-benthic ecosystems, HYDROBIOL, 391(1-3), 1998, pp. 23-32
We developed incubation chambers of clear acrylic extending the full depth
of the water column to measure in situ depth-integrated community metabolis
m in experimental planktonic-benthic ecosystems. A magnetic stirring appara
tus at mid-depth in each chamber prevented stratification and maintained a
vertical turnover time that roughly matched turnover in the experimental ec
osystems. We used the chambers in light-dark experiments to partition the d
epth-integrated photosynthesis and respiration occurring in the experimenta
l ecosystems among water column, wall periphyton, and benthic communities.
Community metabolism measured with the chambers was positively related to t
he chlorophyll-a concentrations of the water column and wall periphyton com
munities. We also found close agreement between the summation of partitione
d community metabolism measured in the chambers and an independent measure
of total ecosystem metabolism in the experimental ecosystems. Incubations i
n chambers and in light-dark bottles revealed similar patterns of water col
umn and wall periphyton community metabolism, but magnitudes differed. In a
ddition to application in experimental ecosystems, this incubation chamber
technique may provide an efficient and realistic measure of water column an
d benthic metabolism and nutrient uptake in lakes and estuaries.