Composition and sources of particulate and dissolved matter in stream and groundwater of the Honeysuckle Creek watershed


An important function of watersheds is the transport of organic matter from terrestrial to aquatic ecosystems. In order to better understand this function, and predict the impacts of climate change, more information is needed on the sources of terrestrial organic matter, the partitioning among particulate and dissolved forms, and the influence of precipitation events. In this investigation, we are looking at the dissolved and particulate matter distribution in stream water and shallow water wells along the Honeysuckle Creek watershed, a 120 ha, first-order watershed in northern Michigan. We are taking water samples during base flow and after a rain event. This water can be filtered to isolate the particulate matter, which is then weighted before and after ignition to obtain total suspended solids. The filtrate can be analyzed for carbon (C), nitrogen (N) concentrations, and stable isotope signatures; as well as for total mercury (THg) concentration. The dissolved matter can be analyzed for organic carbon content using an OI Analytical Aurora TOC (total organic carbon) analyzer. This is providing information about potential sources of the material transported by the water, and giving the opportunity to survey the flow path of material through the watershed. In order to explore the source of this material, we ball mill soil samples from upland and wetland sites into fine powder which is then analyzed for C and N concentrations, and stable isotope signatures, and THg in the same manner as the particulate matter in water.