Effect of algae on flocculation of suspended bed sediments in a large shallow lake. Consequences for ecology and sediment transport processes

TY - JOUR

T1 - Effect of algae on flocculation of suspended bed sediments in a large shallow lake. Consequences for ecology and sediment transport processes

AU - de Lucas Pardo, MiguelAngel

AU - Sarpe, Dirk

AU - Winterwerp, JohanChristian

N1 - 5867, AqE; Data archiving: data archived at Deltares (Delft)

PY - 2015

Y1 - 2015

N2 - Lake Markermeer, a large shallow lake in The Netherlands, suffers from turbidity and ecology problems. As part of a study aiming to mitigate these problems, we study flocculation processes in the lake; in particular, the possible mutual flocculation between algae and re-suspended bed sediments. We show that sediment re-suspended from the bed of the lake can flocculate, forming flocs for which size is a function of the turbulence level in the water column. Moreover, we also demonstrate that algae and re-suspended bed sediments can mutually flocculate, yielding organic-inorganic aggregates. These aggregates have different features to those of their individual components, some of which have been measured and characterized in this paper. Furthermore, the characteristics of the resulting organic-inorganic flocs are strongly influenced by the type of algae in the aggregate. We found that, in the case of flocs consisting of bed sediments and filamentous algae, flocculation yields smaller flocs than for bed sediments only, resulting in an increased turbidity in the water column. In the case of flocs consisting of bed sediments and colonial algae, flocs grow faster and become larger than bed sediment flocs, which may result in the depletion of most colonies from the water column.

AB - Lake Markermeer, a large shallow lake in The Netherlands, suffers from turbidity and ecology problems. As part of a study aiming to mitigate these problems, we study flocculation processes in the lake; in particular, the possible mutual flocculation between algae and re-suspended bed sediments. We show that sediment re-suspended from the bed of the lake can flocculate, forming flocs for which size is a function of the turbulence level in the water column. Moreover, we also demonstrate that algae and re-suspended bed sediments can mutually flocculate, yielding organic-inorganic aggregates. These aggregates have different features to those of their individual components, some of which have been measured and characterized in this paper. Furthermore, the characteristics of the resulting organic-inorganic flocs are strongly influenced by the type of algae in the aggregate. We found that, in the case of flocs consisting of bed sediments and filamentous algae, flocculation yields smaller flocs than for bed sediments only, resulting in an increased turbidity in the water column. In the case of flocs consisting of bed sediments and colonial algae, flocs grow faster and become larger than bed sediment flocs, which may result in the depletion of most colonies from the water column.

KW - Flocculation

KW - Cohesive sediments

KW - Blue-green algae

KW - Markermeer

KW - Turbidity

KW - national

U2 - 10.1007/s10236-015-0841-y

DO - 10.1007/s10236-015-0841-y

M3 - Article

SN - 1616-7341

VL - 65

SP - 889

EP - 903

JO - Ocean Dynamics

JF - Ocean Dynamics

IS - 6

ER -