Increase of microbial biomass in the benthic turbidity zone of Kiel Bight after resuspension by a storm event

Abstract

Near-bottom water samples were collected at 7, 12, 20, 40, and 300 cm above the seabed in situ at two stations in Kiel Bight during calm hydrographic conditions and during a storm-induced subsequent resuspension event in fall 1989. Measurements of seston, particulate organic C, particulate organic N, and microbial biomass revealed storm-related differences in the composition of the particulate matter in the benthic turbidity zone restricted to a height of ∼40 cm above the seabed at both sites. At the offshore site seston levels during the storm were about twice as high as during calm conditions (signed-rank P ≤ 0.005). Increased bacterial numbers and enlarged median cell sizes during the storm resulted in significant (α, 0.069–0.01) increases in bacterial biomass to a height of ∼20 cm above the seabed. Therefore, stimulation of microbial growth by resuspension can provide an additional energy source to the benthic community.