Summer bacterial populations in Mississippi River Pool 19: implications for secondary production

Samples of bacterial population taken from 37 sites in Mississippi River Pool Nineteen showed bacterial biomass in the water column ranging from 0.05 to 1.13 mg carbon per litre. Biomass in the vegetated areas of the pool were significantly higher than the other habitats. Biomass in sediments ranged from 24 to 1073 mg carbon per m2, muddy sediments having a significantly higher biomass than sandy sediments. Bacterial biomass was significantly higher on submersed surfaces of hydrophytes than in sediments supporting the plants. Bacterial production rates in the water column of a vegetated section of the pool ranged from 0.03 to 3.28 g carbon per m3.day. Production of bacterial carbon in a vegetation bed was 5.5 times higher than the production in a nonvegetated channel border area and approximately 50 times that in the main channel. There are 34 references.