Ponggol estuary, located on the northeastern coast of Singapore, is heavily impacted by reclamation, dredging, construction and shipping. Tin, lead, nickel, cadmium, copper and zinc in the particulate and dissolved fraction and in sediments were monitored biweekly in the estuary from July 1999 to June 2000. The concentrations of tin, lead, nickel, cadmium, copper and zinc were observed to range...

Artificial streams were set up to test the relationship between near-bed water velocity and periphyton growth. Periphyton community samples collected from a Japanese stream were incubated for 44 days under a light intensity of 252 ± 72 μmol·photons/m2·s, a temperature of 20–25 ◦C, and three near-bed water velocity classes: low (<17.9 cm/s), moderate (17.9–32.8 cm/s), and high (>32.8 cm/s). A lo...

The effects of prior chronic exposure to atrazine on responses to subsequent acute exposures were investigated using a common benthic diatom. Clonal, axenic cultures of Craticula cuspidata were established from the Platte River (Nebraska) and obtained from a culture collection (unlikely prior exposure to atrazine). All cultures received a chronic 67-d treatment of 1 mg/L atrazine, and growth wa...

Among the mechanisms that allow competing species to coexist are resource partitioning and dietary segregation. The current study uses multiple stable isotopes, carbon ( 13C), nitrogen ( 15N) and sulphur ( 34S), to test the hypothesis that dietary segregation in cohabiting invasive mysids (Limnomysis benedeni and Katamysis warpachowskyi) and gammarids (Dikerogammarus villosus and Gammarus roese...

Applying the recent developments of scale transition theory, we demonstrate a systematic approach to the problem of scaling up local scale interactions to regional scale dynamics with field data. Dynamics on larger spatial scales differ from the predictions of local dynamics alone because of an interaction between nonlinearity in population dynamics at the local scale and spatial variation in d...

The aim of this study was to analyze the effects of flood pulses (intensity) on the richness and composition of periphytic algae in lentic environments of the Upper Paraná River floodplain, over a six-year period. Other factors, such as connectivity of the environments with the main channel of the river and the availability of substrate for the periphyton, were also evaluated. For qualitative a...

The algal groups present in periphyton communities form an important base of autochthonous food webs freshwater streams. Nitrogen (N) and phosphorus (P) are key macronutrients aquatic systems. Excess nutrients benefit some over others. We paired a nutrient-diffusing substrata limitation experiment with high performance liquid chromatography to (a) identify which nutrient(s) limit production, (b...

Ciliates are single celled eukaryotes recognized as key players in the microbial loop of aquatic ecosystems. The present study was carried out on Krka River (Croatia), a karst freshwater ecosystem characterized by tufa barriers, biomineralization and highly diverse communities. main aims were to investigate ciliate community structure biofilm (i.e. periphyton) samples collected from light- dark...