Gesa A. Weyhenmeyer

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Freshwater ecosystems have been repeatedly shown to respond significantly to large-scale climatic fluctuations [e.g., Strub et al., 1985; Firth and Fisher, 1992; George and Taylor, 1995; Anderson et al., 1996; Schindler, 1997]. Because human demand for high-quality fresh water is continually increasing, the practical relevance of such responses for the(More)
While there is a general sense that lakes can act as sentinels of climate change, their efficacy has not been thoroughly analyzed. We identified the key response variables within a lake that act as indicators of the effects of climate change on both the lake and the catchment. These variables reflect a wide range of physical, chemical, and biological(More)
In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean= 0.34°C decade ) between 1985 and 2009. Our analyses show that surface water warming rates are dependent on combinations of climate and local characteristics, rather than just lake location, leading to(More)
We performed intensive sediment trap studies at different water depths and locations in nine Swedish lakes to determine the flux, distribution, and origin of settling particulate matter in the pelagic zone. From these data, we developed a dynamic model that includes important mechanisms controlling fluxes of autochthonous, allochthonous, and resuspended(More)
The seasonality of nutrients and chlorophyll a in Lake Erken (Sweden) was monitored during 1994 to 2001 (warm period) and compared to the time period 1975 to 1979 (cold period). The coupling to weather conditions and potentially influencing factors, such as water temperature, light conditions, and stratification were evaluated. During the warm period the(More)
The quantity of carbon dioxide (CO2) emissions from inland waters into the atmosphere varies, depending on spatial and temporal variations in the partial pressure of CO2 (pCO2) in waters. Using 22,664 water samples from 851 boreal lakes and 64 boreal streams, taken from different water depths and during different months we found large spatial and temporal(More)
The character of organic carbon (OC) in lake waters is strongly dependent on the time water has spent in the landscape as well as in the lake itself due to continuous biogeochemical OC transformation processes. A common view is that upstream lakes might prolong the water retention in the landscape, resulting in an altered OC character downstream. We(More)
PURPOSE In this study, seasonal variations in the concentration profile of four analgesics and one lipid regulator were monitored on their way from a wastewater treatment plant (WWTP) effluent, along a river, and into a lake. METHODS From December 2007 to December 2008, water samples were collected monthly (n=12) from an upstream point, the effluent, four(More)
Inland waters transport large amounts of dissolved organic matter (DOM) from terrestrial environments to the oceans, but DOM also reacts en route, with substantial water column losses by mineralization and sedimentation. For DOM transformations along the aquatic continuum, lakes play an important role as they retain waters in the landscape allowing for more(More)
We surveyed four different river systems in the Greater Montreal region, upstream and downstream of entry points of contamination, from April 2007 to January 2009. The studied compounds belong to three different groups: PPCPs (caffeine, carbamazepine, naproxen, gemfibrozil, and trimethoprim), hormones (progesterone, estrone, and estradiol), and triazine(More)