Biological indices based on the biomass (dry weight, ash content, and chlorophyll-a) of the periphyton in a natural (submersed leaves of Typha domingensis Pers) and in an artificial (plastic hoses) substrate were compared, in experiments performed in summer and winter, in two sampling stations of Imboassica Lagoon, Macaé, Rio de Janeiro. The periphytic community exhibited low biomass at the beg...

(1) This study examines the population ecology of Poecilia gillii (Kner & Steindachner, 1863), a small algaeand detritus-feeding fish, inhabiting sixteen isolated, residual pools of a high-gradient, intermittent stream in Costa Rica following floods which severely reduced the number of fish in the stream. (2) Immediately after the floods, population sizes averaged 20% and pool surface areas 130...

This study aimed to elucidate the effects of periphyton on the microprofiles of oxygen (O2), pH, and oxidation-reduction potential around the stems and leaves of a submerged macrophyte Potamogeton malaianus and on the plant growth in the eutrophic shallow Taihu Lake, China. The microprofiles were measured using a motorized microprofiling system equipped with microsensors. The leaf age of the ma...

Spatial patterns in mercury cycling and bioaccumulation at the landscape level in the Everglades were investigated by collecting and analyzing multimedia samples for mercury species and biogeochemical characteristics from 228 randomly located stations. Higher total mercury (THg) in environmental compartments (surface water, soil, flocculent detrital material (floc), and periphyton) generally oc...

The influence of the herbivorous snail (Physa sp.) on the algal periphyton community from the Gamasiyab River, Kermanshah province in western Iran was examined by establishing a gradient of Physa sp. density in artificial streams. The impact of Physa grazing was evaluated by measuring dry mass, ash-free dry mass (AFDM) and chlorophyll a in the periphyton community. Snails significantly depresse...

Spatial and temporal variations of Cocconeis placentula var. euglypta in drift and periphyton were studied in mountain streams of the Córdoba Province (Argentina). The sampling program was conducted in study sites located on a confluence between different order streams during an annual cycle. Samples were also taken every two hours during the daylight period in high and low water conditions. Th...

The influence of eutrophication of fluvial ecosystems (caused by increased phosphorus concentrations) on periphyton Cu sensitivity is explored from a multi-scale perspective, going from the field to the laboratory. The study design included three tiers: a field study including the characterization of land use and the ecological state of the corresponding river sections in the Fluvià River water...

We examine the potential for nutrient limitation of algal periphyton biomass in blackwater streams draining the Georgia coastal plain. Previous studies have investigated nutrient limitation of planktonic algae in large blackwater rivers, but virtually no scientific information exists regarding how algal periphyton respond to nutrients under different light conditions in smaller, low-flow stream...

Research on aquatic snails usually examines consumption of periphyton, but emergence of large, invasive aquatic snails that prefer macrophytes has necessitated a new understanding about snail herbivory. Ample research exists detailing invasive potential of certain species of applesnails, such as Pomacea canaliculata, to successfully invade aquatic ecosystems. However, very few studies examine d...

The effects of channel bed disturbance on benthic chlorophyll a accrual were examined in three reaches of the Williams Fork River, CO, USA. A field calibrated multidimensional hydraulic model was used for estimation of shear-stress distributions. Sediment grain size was used to determine the critical shear stress for bed movement. Disturbance at a given location is defined as the percentage of ...