Methods and growth chambers are described which permit in situ estimates of the growth rates of chironomid larvae inhabiting litter accumulations in lotic habitats. Instantaneous growth rates (IGRs) for larvae of different sizes ranged from 0.01 to 0.24 mg mg-l ash-free dry mass (AFDM) d-l at stream temperatures of 2.9”15.1”C. IGRs were significantly and linearly related to temperature. Regress...

This study was conducted to determine if salmon carcasses (from spawning adults) increased stream biofilm ash-free dry mass (AFDM) and benthic macroinvertebrate abundance in southeastern Alaska, U.S.A. Thirty-six once-through artificial streams were situated along, and received water and drifting invertebrates from, a natural stream. Two treatments (salmon carcass, control) were sampled six tim...

Oxygen consumption (MO2) and ammonium excretion rates were recorded monthly over 2 yr for the regular Antarctic echinoid Sterechinus neumayeri to investigate metabolic activity in relation to seasonal food limitation (i.e. phytoplankton standing stock) at Adelaide Island (67° 34’ S, 68° 07’ W). Phytoplankton standing stock showed a brief but intense summer bloom and extended winter minima chara...

1. One of two things can happen to allochthonous material once it enters a stream: it can be broken down or it can be transported downstream. The efficiency with which allochthonous material is used is the result of these two opposing factors: breakdown and transport. 2. The present synthesis of new and published studies at Coweeta Hydrologic Laboratory compares biological use versus transport ...

Periphyton from rice-fish environment of Apatani Plateau, Arunachal Pradesh, India was studied for diversity and productivity (Chlorophylla and biomass) on artificial (glass slide) and natural (rice stem) substrates. Periphyton from rice stems, especially, from cultivars locally known as ‘Amo’ were collected from a depth of 7.0-8.0 cm from surface water and 5.0 cm above from the field bottom. G...

The effects of multiple experimental floods in the same year on the ecology of a river (River Spöl) below a large reservoir were investigated. In the flood year (2000), three floods of different magnitude (10 m/s on 15 June, 25 m/s on 5 July, and 10 m/s on 10 August) were implemented, each lasting 7–8 h. Regulated baseflow discharge was maintained at less than 2.5 m/s. Samples of macroinvertebr...

Elevated atmospheric CO2 increases plant C fixation, and much of the soluble C content of deciduous leaf litter entering streams is leached as dissolved organic C (DOC). The effects of DOC from trembling aspen (Populus tremuloides Michaux) leaf litter grown under elevated (ELEV 1⁄4 720 ppm) and ambient (AMB1⁄4 360 ppm) CO2 on stream periphyton were measured during a 35-d experiment in outdoor a...

Microbial succession during leaf breakdown was investigated in a small forested stream in west-central Georgia, USA, using multiple culture-independent techniques. Red maple (Acer rubrum) and water oak (Quercus nigra) leaf litter were incubated in situ for 128 days, and litter breakdown was quantified by ash-free dry mass (AFDM) method and microbial assemblage composition using phospholipid fat...

the influence of the herbivorous snail (physa sp.) on the algal periphyton community from thegamasiyab 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 drymass (afdm) and chlorophyll a in the periphyton community. snails significantly depressed p...