Emerging in-situ sensor technologies provide insight into the ecological function of three Vermont streams


TitleEmerging in-situ sensor technologies provide insight into the ecological function of three Vermont streams
Publication TypeConference Paper and Presentation
Year of Publication2018
AuthorsBowden, WB, Sleeper, R, Schroth, A, Vaughan, M
Conference NameLake Champlain Research Conference
Date Published2018/01
PublisherLake Champlain Basin Program
Conference LocationBurlington, VT
Abstract

Stoichiometric constraints imply that the cycling of carbon and other essential nutrients are closely coupled in space and time in stream ecosystems. Rates of cycling and their driving processes are affected by numerous environmental variables (e.g., temperature and light) and may be modified by land use/land cover. In this study, we used a combination of in-situ sensor technologies and novel modeling techniques to estimate rates of ecosystem metabolism and nitrate uptake in three Vermont streams spanning the forested, agricultural, and urban land cover spectrum. For gross ecosystem production (GEP) and ecosystem respiration (ER), we found statistically significant between-site differences and within-site seasonal dynamics, which followed patterns in light and nutrient availability. We observed seasonal patterns in the metabolic sub-parameters alpha (rate of production at low light levels) and Pmax (maximum rate of production at high light levels) that may reflect community-scale algal succession or adaption to changing environmental conditions. We utilized a novel modelling technique to calculate nitrate uptake based on diurnal fluctuations in dissolved nitrate concentrations measured continuously by in-situ spectrophotometers. This approach vastly increased the number of nitrate uptake estimates we obtained compared to traditional field experiments (e.g., nitrate or nitrogen-15 isotope addition experiments). Nitrate uptake rates were strongly correlated with rates of GEP, especially in the most productive stream. However, based on stoichiometric considerations, the rates of nitrate uptake were as much as ten times higher than expected based on the rates of GEP. This suggests that processes beyond biological uptake by primary producers in these streams may contribute significantly to diurnal fluctuations in nitrate concentration. The results of this study suggest that emerging in-situ sensor technologies can be used to measure important metrics of stream ecosystem function that are responsive to land use/land cover differences.

URLhttp://www.lcbp.org/water-environment/data-monitoring/lake-champlain-research-conference/
Status: 
Published
Attributable Grant: 
BREE
Grant Year: 
Year2
Acknowledged VT EPSCoR: 
Ack-Yes
2nd Attributable Grant: 
NEWRnet
2nd Grant Year: 
2nd_Post_Grant
2nd Acknowledged Grant: 
2nd_Ack-Yes