Reduction of germination frequency in Anabaena akinetes by sediment drying: a possible method by which to inhibit bloom formation.

The effect of desiccation on germination frequency of Anabaena akinetes was investigated to evaluate the practical usefulness of sediment drying in reservoirs as a measure of inhibition of Anabaena bloom formation. Sediment samples taken from a small reservoir, where an abundance of Anabaena blooms occur every summer were desiccated in the outdoors and in an incubator at 5, 10, 15, and 25 degrees C. As a result, the germination frequency of Anabaena akinetes was strongly inhibited in comparison with that of Anabaena akinetes preserved in a refrigerator without desiccation as a control.

Demography and matrix analysis on a natural Pterocarya rhoifolia population developed along a mountain stream.

The population structures and dynamics of a dominant riparian canopy species, Pterocarya rhoifolia (Juglandaceae), were analyzed based on the census data collected for the 7 years from 1989 through 1996. A study plot was established over an environmental gradient that included the lower hill-slope, river terrace, and low-level floodplain of a riparian area within a 2.8-ha cool-temperate forest stand.

Fluorescence-assisted image analysis of freshwater microalgae.

We exploit a property of microalgae-that of their ability to autofluoresce when exposed to epifluorescence illumination-to tackle the problem of detecting and analysing microalgae in sediment samples containing complex scenes. We have added fluorescence excitation to the hardware portion of our microalgae image processing system. We quantitatively measured 120 characteristics of each object detected through fluorescence excitation, and used an optimized subset of these characteristics for later automated analysis and species classification.

THE EFFECT OF IRRADIANCE ON THE GROWTH OF DIFFERENT FORMS OF FRESHWATER DIATOMS: IMPLICATIONS FOR SUCCESSION IN ATTACHED DIATOM COMMUNITIES.

The growth rates of 12 strains of attached freshwater diatoms were examined as a function of irradiance. The results were used to determine physiological parameters in the growth-irradiance relationships. Values of G (maximum growth rate) and I  (irradiance at half of G ) correlated with successional phase.