The study of pesticide effects on algae, and diatoms in particular, was focused on photosynthesis and biomass growth disturbances. Few studies have been performed to investigate the effects of these toxic agents on intracellular structures of diatom cells. Nuclear alterations and cell wall abnormalities were reported for diatoms exposed to toxic compounds. Nevertheless, the cellular mechanisms ...

The JGOFS program and NASA ocean-color satellites have provided a wealth of data that can be used to test and validate models of ocean biogeochemistry. A coupled three-dimensional general circulation, biogeochemical, and radiative model of the global oceans was validated using these in situ data sources and satellite data sets. Biogeochemical processes in the model were determined from the infl...

We investigated the animal–food size relationships of an invertebrate grazer community that feeds on the epiphytic diatoms of mosses in a Québec stream. The relationship between invertebrate head width and maximum size of ingested diatoms was significant (r2 5 0.57, n 5 82, p , 0.00001). This relationship did not differ significantly among widely different taxa of insects, crustaceans, and worm...

In this report we describe different combinations of physical separation and antibiotic treatment to remove associated bacteria from freshwater diatoms. Diatoms were purified either from natural epilithic biofilms or from uni-algal cultures. We found that for most strains different purification procedures have to be combined individually. In a new approach we show that for some diatom strains t...

Diatoms are extremely diverse ubiquitous microalgae. This makes them good indicators of the quality of aquatic ecosystems, and they have been used for this purpose for the past 50 years. Since 2000, the European Water Framework Directive has required them to be used for assessing the ecological quality of watercourses. A typological framework has to be devised in order to compa...

a r t i c l e i n f o This paper presents a hierarchical multi-label classification (HMC) system for diatom image classification. HMC is a variant of classification where an instance may belong to multiple classes at the same time and these classes/labels are organized in a hierarchy. Our approach to HMC exploits the classification hierarchy by building a single predictive clustering tree (PCT)...

When adult females of Calanus pacificus are fed on monospecific cultures of centric diatoms which grow as single cells, a predictive relationship is found between feeding behavior of the copepods and size and concentration of food particles. Ingestion rate of copepods increases linearly with cell concentration up to a maximal rate. This maximal ingestion rate, expressed as carbon, is the same f...

The study of phototrophic biofilms from Maltese catacombs has shown that their distribution within catacombs does not show a significant dependence on orientation of catacomb and their location inside the catacombs. A decrease on species richness is observed when light availability diminishes, but the composition of biofilms does not change significantly. The proportion of green algae has a sli...