Long-term (1987-2012) water quality monitoring in 36 acid-sensitive Swedish lakes shows slow recovery from historic acidification. Overall, strong acid anion concentrations declined, primarily as a result of declines in sulfate. Chloride is now the dominant anion in many acid-sensitive lakes. Base cation concentrations have declined less rapidly than strong acid anion concentrations, leading to...

Both nitrate (NO3-N) and ammonia (NH4-N) concentrations are in general highly variable during a lake’s seasonal cycle. During the growing seasonal peak, such concentrations can be very low due mainly to its’ sequestration by phytoplankton. With the aim to study NO3-N and NH4-N mean concentration variation along the increase of the trophic state of lakes, this study simultaneously analyses the i...

An association between acidification of lakes and high mercury concentrations in fishes has been reported. In northern Wisconsin (USA), for example, walleye (Stizostedion vitreum) in naturally acidic lakes have higher mercury concentrations than walleye in circumneutral lakes (Weiner, 1983). In this study a bioenergetic based model for mercury uptake is applied to identify potential causes of h...

pollution has become a very serious threat to our environment. monitoring pollution is the rst step toward planning to save the environment. the use of dierential equations, monitoring pollution has become possible. in this paper, a ritz-collocation method is introduced to solve non-linear oscillatory systems such as modelling the pollution of a system of lakes. the method is based upon bernoul...

The boreal biome contains the world’s largest number of lakes that are sensitive to anthropogenic acidification. Thousands of poorly buffered Canadian boreal lakes (Fig. 1) were acidified during the 20 century by acid deposition generated from industrial activity (1). Since 1970, some boreal lakes have shown chemical and biological recovery because of reductions in acidic sulfur oxide emissions...

Submersed aquatic plants are a key component of shallow, clear water lakes contributing to primary production and water quality. High mountain lakes are naturally fishless although invasive trout and most recently minnows have been introduced causing a major impact on fauna richness. The Pyrenean high mountain range has preserved soft-water oligotrophic boreal isoetids in their southern limit o...

Introduction: The existence of probable lakes on Mars has been recognized for more than two decades [1-4]. Lakes can either be open-basins with both inlet valley(s) and an outlet valley [e.g., 5], or they can be closed-basins that lack an outlet [e.g., 6]. Although both open-and closed-basin lakes were likely present on early Mars, open-basin lakes are easier to study, and we can have higher co...

The transport and deposition of anthropogenic nitrogen (N) to downwind ecosystems is significant and can be a dominant source of new N to many watersheds. Bacterially mediated denitrification in lake sediments may ameliorate the effects of N loading by permanently removing such inputs. We measured denitrification in sediments collected from lakes in the Colorado Rocky Mountains (USA) receiving ...

The Great Lakes of East Africa are among the world's most important freshwater ecosystems. Despite their importance in providing vital resources and ecosystem services, the impact of regional and global environmental drivers on this lacustrine system remains only partially understood. We make a systematic comparison of the dynamics of the bio-optical and thermal properties of thirteen of the la...

We surveyed 15 lakes during the growing season of 2014 in Arctic lakes of southwest Greenland to determine which factors influence methane concentrations in these systems. Methane averaged 2.5 μmol L-1 in lakes, but varied a great deal across the landscape with lakes on older landscapes farther from the ice sheet margin having some of the highest values of methane reported in lakes in the north...