Summer sedimentation in six shallow arctic lakes

Abstract

The movement of sediment between the lake bottom and water column of shallow lakes can be sizeable due to the large potential for resuspension in these systems. Resuspended sediments have been shown to alter phytoplankton community composition and elevate water column production and nutrient concentrations. We measured the summer sedimentation rates of two lakes in 2003 and six lakes in 2004. All lakes were shallow and located in the Alaskan Arctic. In 2004, turbidity, light attenuation, total sediment:chlorophyll a mass in the sediment traps, and thermal stratification were also measured in each of the lakes. The sediment:chlorophyll a mass was much greater than if the sediment was derived from phytoplankton production in all of the lakes, indicating that the source of the sedimenting material was resuspension and allochthonous inputs. Consistent with these findings, the temporal variation in sedimentation rate was synchronous between most lakes, and sedimentation rate was positively related to wind speed and rainfall suggesting that sedimentation rate was strongly influenced by landscape-scale factors (e.g., wind and rain events). Two of the lakes are located on deposits of loess that accumulated during past glacial periods. These two lakes had sedimentation rates that were significantly greater and more variable than any of the other lakes in the study, as well as high turbidity and light attenuation. Our results indicate that sedimentation in these shallow arctic lakes is supported primarily by allochthonous inputs and resuspension and that landscape-scale factors (e.g., weather and geology) impact on the transport of materials between the lake bottom and water column.

Effects of food-web structure on the quantity and the elemental quality of sedimenting material in shallow lakes

“…However, the release of nutrients from sediment by chemical processes can represent significant inputs of nutrients for pelagic systems (e.g., Reynolds, 1996). In particular, sediment resuspension and remineralization following agitation events can lead to huge increases in nutrients (Sanford, 1992;Fortino et al, 2009). Even after reduction of nutrient loading in eutrophic lakes, the sediment compartment can act as a source of nutrients able to sustain important algal developments (Marsden, 1989;Søndergaard et al, 2007).…”

The Effect of Land Use on Isotope Signatures of the Detritus Pathway in an Urban Wetland System

“…However, at higher resuspension levels, these microbiota mix (Jonge and van den Bergs 1987;Wainright 1987;Dupuy et al 2013), and might show similar isotopic signatures. But the lack of a correlation between SOM and BOM signatures suggests a low resuspension of sediments in the water column (Peterson 1987;Hodell and Schelske 1998;Fortino et al 2009). This is surprising considering the high abundance of carp and tilapia in the system (Zambrano, et al 2010b), the local motorboat traffic (Garrad and Hey 1987) and the activity of traditional boats (trajineras), which are propelled by a pole that is inserted into the sediment.…”

Spatiotemporal patterns in nutrient loads, nutrient concentrations, and algal biomass in Lake Taihu, China

“…Concentrations of TP and TN recorded in Lake Taihu sediments (% dry mass) ranged from 0.01 to 0.015% and 0.01 to 0.66%, respectively . In large, shallow lakes like Lake Taihu, it is common for total suspended solids and nutrients to be suspended by wind induced wave action and diffusion, disturbing the interface between water and sediment (Cao et al 2007, Fortino et al 2009, Niemisto et al 2009). Estimated resuspension of TP and TN from sediments (2.1 × 10 7 and 8.1 × 10 7 kg/yr, respectively) in Lake Taihu is 2 to 6 times greater than external input from the basin (Qin et al 2006), suggesting that resuspension contributes significantly to nutrient concentrations in the water column (Cyr et al 2009, Song et al 2010; however, sediments remain a sink for P but not necessarily for N. During the summer cyanobacteria bloom, N is commonly removed by denitrification.…”