BACKGROUND Nutrient management in rivers and streams is difficult due to the spatial and temporal variability of algal growth responses. The objectives of this project were to determine the spatial and seasonal in situ variability of trophic status in the Lake Waco/Bosque River watershed, determine the variability in the lotic ecosystem trophic status index (LETSI) at each site as indicators of...

Seasonal and inter-annual variability in satellite-derived estimates of near-surface chlorophyll a concentration and primary production were examined in three regimes (shelf, slope and deep oceanic waters) off Washington and Vancouver Island from 1998 to 2002. Wind-induced upwelling predominates in late spring and summer, coinciding with the maximum in solar radiation, leading to increased accu...

Plant height, biomass production, assimilatory functions and chlorophyll accumulation of Panicum maximum and Stylosanthes hamata in intercropping systems was influenced significantly under elevated CO2 (600 +/- 50 ppm) in open top chambers (OTCs). The plant height increased by 32.0 and 49.0% over the control in P. maximum and S. hamata respectively in intercropping system under elevated CO2 ove...

—Stock–recruit models typically use only spawning stock size as a predictor of recruitment to a fishery. In this paper, however, we used spawning stock size as well as larval density and key environmental variables to predict recruitment of white crappies Pomoxis annularis and black crappies P. nigromaculatus, a genus notorious for variable recruitment. We sampled adults and recruits from 11 Oh...

intercropping is a correct method of management for crop production and leads to improvement of resource absorption and use by plants. in order to evaluate light interception and some characteristics of canopy in monocropping and intercropping of maize (zea mays l.) and faba bean (vicia faba l.) under climatic conditions of tabriz, a field experiment was conducted in 2006-2007 at the research s...

In this study the variations in surface reflectance properties and pigment concentrations of Antarctic moss over species, sites, microtopography and with water content were investigated. It was found that species had significantly different surface reflectance properties, particularly in the region of the red edge (approximately 700 nm), but this did not correlate strongly with pigment concentr...

A methodology is presented for retrieving phytoplankton chlorophyll-a concentration from space. The data to be inverted, namely, vectors of top-of-atmosphere reflectance in the solar spectrum, are treated as explanatory variables conditioned by angular geometry. This approach leads to a continuum of inverse problems, i.e., a collection of similar inverse problems continuously indexed by the ang...