New remote sensing technologies have emerged to quantitatively assess submersed aquatic vegetation abundance and distribution. We evaluated a hydroacoustics global positioning system to map the percent of the water column occupied by submersed vegetation (referred to here as biovolume) in three Minnesota (USA) lakes. We evaluated the relative accuracy and precision of digital biovolume maps pro...

Atrazine bioconcentration and uptake were determined for eight freshwater green algae and diatoms. Atrazine uptake was extremely rapid in all species examined, with nearly 90% of total uptake occurring within the first hour of exposure. Within each division, different species had different bioconcentration capacities, although the accumulation of atrazine was consistently higher in green algae ...

We analyzed sediment elemental composition (C, N, P, and Si) and planktonic diatom fossils from the top 32 cm of a short core (55 cm) from Yellowstone Lake (Wyoming), tracking deposition from about 1650 to 1998. Associations between fossil communities and sediment chemistry were measured by rank-order correlation to gauge decadal scale relationships between lake chemistry and phytoplankton comm...

Rising levels of ultraviolet radiation (UVR) striking the Earth’s surface have led to numerous studies assessing its inhibitory effects on phytoplankton and periphyton in aquatic systems. Mineral nutrients such as nitrogen (N) and phosphorus (P) have been shown to increase aspects of algal metabolism and compensate for UVR inhibition. An in situ substratum enrichment technique and UV shielding ...

By infecting multiple host species and acting as a food resource, parasites can affect food web topography and contribute to ecosystem energy transfer. Owing to the remarkable secondary production of some taxa, parasite biomass - although cryptic - can be comparable to other invertebrate and vertebrate groups. More resolved estimates of parasite biomass are therefore needed to understand parasi...

Iron (Fe) is widely suspected as a key controlling factor of N2 fixation due to the high Fe content of nitrogenase and photosynthetic enzymes complex, and to its low concentrations in oceanic surface seawaters. The influence of Fe limitation on the recently discovered unicellular diazotrophic cyanobacteria (UCYN) is poorly understood despite their biogeochemical importance in the carbon and nit...

Phytoplankton biomass is a variable used in ecological studies and monitoring potentially toxic cyanobacterial blooms. Biomass indicators of this community range from general indirect, such as chlorophyll concentrations, to specific quasi-direct measures biovolume. Based on the results survey addressed Latin American scientists technicians well bibliographic search, we discuss relevance using b...

Abstract Ceratium furcoides is an invasive species that has caused ecological imbalance in several reservoirs Brazil. This study investigates the main factors may favor occurrence of blooms a tropical reservoir from Northeast Brazil, during extreme drought season. Samples containing phytoplankton were collected monthly February to September 2017. Quantitative analysis C. was performed and cell ...