A numerical model describing xanthophyll dynamics in phytoplankton has been developed and used to investigate cellular photoprotective response. The model assumes that, under the transition from limiting to supra-saturating light, the xanthophyll cycling pigments (PX) synthesis implies first (on a time scale of tens of minutes) a stoichiometric conversion of the already existing fucoxanthin (FU...

The Great Lakes of East Africa are among the world's most important freshwater ecosystems. Despite their importance in providing vital resources and ecosystem services, the impact of regional and global environmental drivers on this lacustrine system remains only partially understood. We make a systematic comparison of the dynamics of the bio-optical and thermal properties of thirteen of the la...

In this paper, we consider a two species non-autonomous discrete competitive phytoplankton system with one toxin producing phytoplankton. We show that for such kind of system, it is also possible one of the components be driven to extinction while the other one will be globally attractive with any positive solution of a discrete logistic equation under some conditions. Our results supplement th...

Viral dynamics, community structure, and the impact of viruses on phytoplankton mortality in comparison with microzooplankton grazing were determined in the natural iron-fertilized waters southeast of the Kerguelen Islands, Southern Ocean, during the austral summer (January–February 2005). The study area was characterized by a phytoplankton bloom above the Kerguelen Plateau and the high-nutrien...

Subtropical estuaries worldwide face increased pressure on their ecosystem health and services due to increasing human population growth and associated land use/land cover changes, expansion of ports, and climate change. We investigated freshwater inflows (river discharge) and the physico-chemical characteristics of Galveston Bay (Texas, USA) as mechanisms driving variability in phytoplankton b...

phytoplankton taxa composition of the caspian sea were evaluated by using samples collected at 12 stations along the iranian coast of the caspian sea between 1996 and 2010. this study identified 158 phytoplankton species consisted of diatoms (70 species), dinoflagellates (23 species), chlorophytes (29 species), cyanophytes (31 species), and euglenoids (5 species). the dominant species were the ...

Changes in the biomass of benthic bivalves can cause dramatic changes in total grazing pressure in aquatic systems, but few studies document ecosystem-level impacts of these changes. This study documents a massive decline in phytoplankton biomass concurrent with the invasion of an exotic benthic bivalve, the zebra mussel (Dreissena polymorpha), and demonstrates that the zebra mussel actually ca...

A literature synthesis of phytoplankton growth (m) and grazing (m) rate estimates from dilution experiments reveals that microzooplankton account for most phytoplankton mortality in the oceans, averaging 60e75% of daily phytoplankton production (PP) across a spectrum of open-ocean and coastal systems. For reasonable estimates of gross growth efficiency (GGEZ 30e40%), such impacts imply that sec...

Wind-driven upwelling variability and local topography cause an upwelling shadow in the northern region of Monterey Bay, California, to persist seasonally. The present study applied partial least squares regression to a 7-yr time series collected within this retentive feature for the purpose of evaluating the environmental controls on total autotrophic phytoplankton (as chlorophyll a) and picop...

During the last few years theoretical works have shed new light and proposed new hypotheses on the mechanisms which regulate the spatio-temporal behaviour of phytoplankton communities in marine pelagic ecosystems. Despite this, relevant physical and biological issues, such as effects of the time-dependent mixing in the upper layer, competition between groups, and dynamics of non-stationary deep...