Abstract Niche differentiation is a key stabilizing mechanism in the maintenance of biodiversity and species coexistence. Recent work shows that trophic niche partitioning between parrotfishes (Labridae: Scarini) more extensive than previously described. One Indo-Pacific species, Scarus spinus , appears highly specialized, scraping crustose coralline algae (CCA) with powerful oral jaws. CCA are...

Eutrophication has been one of the largest environmental problems in aquatic ecosystems during the past decades, leading to dense, and often toxic, cyanobacterial blooms. In a way to counteract these problems many lakes have been subject to restoration through biomanipulation. Here we combine 13 years of monitoring data with experimental assessment of grazing efficiency of a naturally occurring...

antifungal and antibacterial activity of some heterocystous cyanobacteria from paddy-fields in the north of iran was studied. soil samples were collected from paddy-fields of gillan, mazandaran and golestan provinces and cyanobacteria were isolated. supernatants, methanolic and hexane extracts from biomass of 150 strains of cyanobacteria were isolated and screened against six strains of bacteri...

Herbivorous fish feed on cyanobacteria. Digestability differs, however, between cyanobacteria species without mucous cover and mucilaginous genera such as Microcystis. The latter can pass fish guts almost undamaged, and it has been hypothesized that they can take up nutrients during gut passage. Here we tested whether live Microcystis, as food for juvenile roach labeled with 33P, indeed showed ...

the toxicity of 7 herbicides to the three cyanobacteria was tested in this work. the results indicated that: (1) there was a highly significant relationship between dried weight or chlorophyll-a and od680nm for tested cyanobacteria; (2) the toxicity of the tested herbicides with the order from high to low was: photosynthesis-inhibiting > accase inhibitor > protox inhibiting herbicides; (3) the ...

Helcom scenario modelling suggests that the Baltic Sea, one of the largest brackish-water bodies in the world, could expect increased precipitation (decreased salinity) and increased concentration of atmospheric CO2 over the next 100 years. These changes are expected to affect the microplanktonic food web, and thereby nutrient and carbon cycling, in a complex and possibly synergistic manner. In...

Cyanobacteria are prokaryotic, plantlike organisms present in lakes, recreational waters, and reservoirs, and often dominate phytoplankton communities in warm, nutrient-enriched hard waters. A stable water column rich in certain nutrients, especially nitrogen and phosphorus, is associated with favorable environmental conditions that support development of cyanobacterial population maxima or "bl...

Großer Müggelsee and Langer See are limnologically similar but during an investigation from 1990 until 1993 marked differences were observed in the species that dominated during the summer blooms. Two distinct planktonic communities could be recognised, one dominated by ”Planktothrix agardhii” and the other by ”Aphanizomenon flos-aquae/Microcystis spp.”. A sensitive moment for the differentiati...

In order to accommodate the physiologically incompatible processes of photosynthesis and nitrogen fixation within the same cell, unicellular nitrogen-fixing cyanobacteria have to maintain a dynamic metabolic profile in the light as well as the dark phase of a diel cycle. The transition from the photosynthetic to the nitrogen-fixing phase is marked by the onset of various biochemical and regulat...

Small-bodied cladocerans and cyclopoid copepods are becoming increasingly dominant over large crustacean zooplankton in eutrophic waters where they often coexist with cyanobacterial blooms. However, relatively little is known about their algal diet preferences. We studied grazing selectivity of small crustaceans (the cyclopoid copepods Mesocyclops leuckarti, Thermocyclops oithonoides, Cyclops k...