The challenges to live in the open water and the diversity of habitats in the marine environments prompts phytoplankton to devise strategies which often involve production of toxins by Harmful Algal Bloom (HAB) and rapid production of metabolites from non-toxic precursor. The functional response of the predator is described by Holling type IV. We investigate wave phenomena and non-linear non-eq...

*Correspondence: Esteban Acevedo-Trejos, Systems Ecology Group, Leibniz Center for Tropical Marine Ecology, Fahrenheitstrasse 6, 28359 Bremen, Germany e-mail: esteban.acevedo@ zmt-bremen.de It is expected that climate change will have significant impacts on ecosystems. Most model projections agree that the ocean will experience stronger stratification and less nutrient supply from deep waters. ...

Viruses infecting marine phytoplankton drive phytoplankton diversity, terminate blooms and shuttle genetic material. Assessments of the scale of viral impacts on trophic networks are, however, speculative. We investigated fluxes of DNA between host and virus during infection of the prasinophyte alga Micromonas pusilla by phycodnavirus MpV SP1. Under a light-dark regimen, viral genomes accumulat...

BACKGROUND AND OBJECTIVES Phytoplanktons are organisms with a very high diversities and global distribution in different habitats. The high distribution of phytoplankton is due to ecological flexibility and their ability to tolerate different climatic conditions and environmental stress. Phytoplankton is the most sensitive biological indicators of water resources. The purpose of this study was ...

A functional gene microarray was developed and used to investigate phytoplankton community composition and gene expression in the English Channel. Genes encoding the CO2 -fixation enzyme RUBISCO (rbcL) and the nitrate assimilation enzyme nitrate reductase (NR) representing several major groups of phytoplankton were included as oligonucleotide probes on the "phytoarray." Five major groups of euk...

A short-timescale sampling of phytoplankton abundance and diversity was carried out at Redang Island waters, South China Sea. Physico-chemical variables measured at four intervals over a day were relatively stable (temperature = 29 ± 0.6°C ; salinity = 27 ± 2 ppt, pH = 7.8 ± 0.1; total alkalinity = 2025 ± 33 μeq l–1) whereas inorganic nutrient concentrations (NH4 = 1.36 ± 0.51 μM; NO2 = 0.06 ± ...

In aquatic ecosystems, species diversity is known to be higher in poor nutrient conditions. The enrichment of nutrition often induces the loss of biodiversity. This phenomenon is called the paradox of enrichment, since higher nutrient levels can support more species. Furthermore, the species diversity is usually high in most natural communities of phytoplankton. However, the niches of planktoni...

The goal of this thesis is to study the causes and consequences of the size structure of marine planktonic ecosystems. To this end, a theoretical (continuous) size spectrum model was developed. Phytoplankton and zooplankton biomass is represented in the model as functions of their respective biomass size spectrums. Thus, the model allows the natural recovery of the continuous size spectrum for ...

The present study reports the phytoplankton abundance, dominance and co-existence relationships in the eutrophic Carpina reservoir, Pernambuco, Brazil. Sampling was carried out at six different depths bimonthly at a single reservoir spanning two climatic periods: dry season (January, September, and November 2006) and rainy season (March, May, and July 2006). Density, abundance, dominance, speci...

In this paper, we derive and analyze a mathematical model for the interactions between phytoplankton and zooplankton in a periodic environment, in which the growth rate and the intrinsic carrying-capacity of phytoplankton are changing with respect to time and nutrient concentration. A threshold value: "Predator's average growth rate" is introduced and it is proved that the phytoplankton-zooplan...