In temperate systems, phytoplankton spring blooms deplete inorganic nutrients and are major sources of organic matter for the microbial loop. In response to phytoplankton exudates and environmental factors, heterotrophic microbial communities are highly dynamic and change their abundance and composition both on spatial and temporal scales. Yet, most of our understanding about these processes co...

We present a simple nutrient-phytoplankton-zooplankton (NPZ) model that incorporates adaptive evolution and allometric relations to examine the patterns and consequences of adaptive changes in plankton body size. Assuming stable environmental conditions, the model makes the following predictions. First, phytoplankton should evolve toward small sizes typical of picoplankton. Second, in the absen...

PETROVA, D., 2008. Major bloom producing phytoplankton species in the lakes along the Bulgarian Black Sea Coast. Bulg. J. Agric. Sci.; 14: 201-208 Archive data analysis shows that during the different periods of anthropogenic impact phytoplankton production reaches pathologically high levels. Thus, phytoplankton is assumed as an indicator of marine water quality and ecological health. Its long-...

Phytoplankton occurrence and dynamics in rivers are mainly shaped by hydrophysical conditions and nutrient availability. Phytoplankton main structuring factors have been poorly studied in West African rivers, and this study was undertaken to identify these conditions in two tropical rivers that vary in size and human impact. For this, environmental variables and phytoplankton monthly samples we...

The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phy...

Phytoplankton require light for photosynthesis. Yet, most phytoplankton species are heavier than water and therefore sink. How can these sinking species persist? Somehow, the answer should lie in the turbulent motion that redisperses sinking phytoplankton over the vertical water column. Here, we show, using a reaction-advection-diffusion equation of light-limited phytoplankton, that there is a ...

Variations in phytoplankton composition were observed over 2.7 years in two warm temperate reservoirs in north central Texas, Joe Pool Lake (JPL) and Eagle Mountain Lake (EML), and analysed in relation to temperature, light, dissolved nutrients, seston nutrient ratios and hydrological variables. The dominant variations in both phytoplankton composition and environmental variables were seasonal ...

Phytoplankton vertical and diel dynamics in a small shallow lake (Lake Monte Alegre, Ribeirão Preto, state of São Paulo) were investigated in two climatological periods: July 2001 (cool-dry season) and March 2002 (warm-rainy season). Monte Alegre is a eutrophic reservoir, with a warm polymictic discontinuous circulation pattern. The lake was thermally stratified in both periods, although dissol...

A previous multiyear study observed correlations between bacterioplankton community composition (BCC) and abundance and the dynamics of phytoplankton populations and bacterivorous grazers in a humic lake. These observations generated hypotheses about the importance of trophic interactions (both top-down and bottom-up) for structuring bacterial communities in this lake, which were tested using t...

Phytoplankton blooms are geochemically and ecologically important, but current understanding of the causes of phytoplankton blooms provides little power to predict the timing, extent, and distribution of blooms. In this thesis, I discuss the implications of light limitation for phytoplankton bloom patchiness and community structure by modeling phytoplankton as reacting tracers in a reaction-adv...