Nutrient pollution and associated eutrophication of freshwaters threaten the ecological integrity and the services provided to humans by lakes. We examined how human residential development influenced the level of lake eutrophication in the Seattle, WA, USA, region. We surveyed 30 lakes and measured 3 indicators of eutrophication: concentrations of chlorophyll-a and phosphorus, and the proporti...

Strawson proposed in the early seventies an attractive threefold distinction regarding how context bears on the meaning of ‘what is said’ when a sentence is uttered. The proposed scheme is somewhat crude and, being aware of this aspect, Strawson himself raised various points to make it more adequate. In this paper, we review the scheme of Strawson, note his concerns, and add some of our own. Ho...

Plankton samples were collected from six remote freshwater and saline lakes located at altitudes of 3,204 to 4,718 m and 1,000 km apart within an area of ca. 1 million km(2) on the eastern Tibetan Plateau to comparatively assess how environmental factors influence the diversity of bacterial communities in high-altitude lakes. The composition of the bacterioplankton was investigated by analysis ...

It has been suggested that both niche-based and neutral mechanisms are important for biological communities to evolve and persist. For communities in extreme and isolated environments such as caves, theoretical and empirical considerations (low species turnover, high stress, strong convergence owing to strong directional selection) predict neutral mechanisms and functional equivalence of specie...

The trophic importance of bacterioplankton as a source of carbon and sulfur nutrition for consumers in meromictic lakes was tested using stable carbon (delta 13C) and sulfur (delta 34S) isotopic measurements. Studies in three lakes near Syracuse, New York, showed that most consumers ultimately derive their C and S nutrition from a mixture of terrestrial detritus, phytoplankton, and littoral v...

Assessment of lake impairment status and identification of threats' type and source is essential for protection of intact, enhancement of modified, and restoration of impaired lakes. For regions in which large numbers of lakes occur, such assessment has usually been done for only small fractions of lakes due to resource and time limitation. This study describes a process for assessing lake impa...

We visited 51 lakes in Costa Rica as part of a broad-based survey to document their physical and chemical characteristics and how these relate to the mode of formation and geographical distribution of the lakes. The four oxbow lakes were low in elevation and tended to be turbid, high in conductivity and CO2, but low in dissolved O2; one of these, L. Gandoca, had a hypolimnion essentially compos...

Due to the great climatic variety and the peculiar north–south orographic distribution, Argentinean lake systems include a wide diversity of aquatic environments. The deepest lakes are situated in the Andean Patagonia and Tierra del Fuego, and range from ultraoligotrophic to oligotrophic. Patagonian Plateau lakes are shallower than Andean lakes and usually range from mesotrophic to eutrophic. A...

Lakes are important water resources and integral parts of the natural ecosystem, and it is of great significance to study the evolution of lakes. The area of each lake increased and decreased at the same time in natural condition, only but the net change of lakes’ area is the result of the bidirectional evolution of lakes. In this paper, considering the effects of net fragmentation, net attenua...