No abstract

No abstract

No abstract

During the last two decades the potentially toxic dinoflagellate Prorocentrum minimum (PAVILLARD) SCHILLER has successfully established itself in the Baltic Sea. It is now a dominant summer species in the southern Baltic proper, and reaches as far into the low salinity of the northern Baltic as the central Gulf of Finland. In the 1990s, it developed several coastal blooms in the eastern and northern Baltic proper, but occurred irregularly between years. Field data show that P. minimum can grow at salinities below 5 PSU, confirming its potential to penetrate farther into the low saline part of the Baltic Sea. Biometric data show that P. minimum cells differ significantly in size between areas in the Baltic Sea.Internat. Rev. Hydrobiol. 85 2000 5-6 561-575

Size and shape profoundly influence an organism’s ecophysiological performance and evolutionary fitness, suggesting a link between morphology and diversity. However, not much is known about how body shape is related to taxonomic richness, especially in microbes. Here we analyse global datasets of unicellular marine phytoplankton, a major group of primary producers with an exceptional diversity of cell sizes and shapes and, additionally, heterotrophic protists. Using two measures of cell shape elongation, we quantify taxonomic diversity as a function of cell size and shape. We find that cells of intermediate volume have the greatest shape variation, from oblate to extremely elongated forms, while small and large cells are mostly compact (e.g. spherical or cubic). Taxonomic diversity is strongly related to cell elongation and cell volume, together explaining up to 92% of total variance. Taxonomic diversity decays exponentially with cell elongation and displays a log‐normal dependence on cell volume, peaking for intermediate‐volume cells with compact shapes. These previously unreported broad patterns in phytoplankton diversity reveal selective pressures and ecophysiological constraints on the geometry of phytoplankton cells which may improve our understanding of marine ecology and the evolutionary rules of life.

:Adverse effects of invasive alien species (IAS), or biological pollution, is an increasing problem in marine coastal waters, which remains high on the environmental management agenda. All maritime countries need to assess the size of this problem and consider effective mechanisms to prevent introductions, and if necessary and where possible to monitor, contain, control or eradicate the introduced impacting organisms. Despite this, and in contrast to more enclosed water bodies, the openness of marine systems indicates that once species are in an area then eradication is usually impossible. Most institutions in countries are aware of the problem and have sufficient governance in place for management. However, there is still a general lack of commitment and concerted action plans are needed to address this problem. This paper provides recommendations resulting from an international workshop based upon a large amount of experience relating to the assessment and control of biopollution. Highlights► We summarize the results of an international workshop on marine biopollution. ► We recommend science-based information support for bioinvasion management. ► We outline types of bioinvasion monitoring and consider topical research needs. ► We emphasize the role of taxonomy training and public involvement. ► Biopollution should be treated in the same way as any other type of pollution.

No abstract

Organisms' size and shape have a profound influence on ecophysiological performance and evolutionary fitness, suggesting a link between morphology and diversity. While unimodal relationships between size and species richness were found for many taxa(1-4), much less is known on how richness is related to shape, in particular in the microbial realm. Here we analyse a novel globally extensive data set of marine unicellular phytoplankton, the major group of photosynthetic microbes, which exhibit an astounding diversity of cell sizes and shapes(5). We quantify the variation in size and shape and explore their effects on taxonomic diversity(6, 7). We find that cells of intermediate volume exhibit the greatest shape variation, with shapes ranging from oblate to extremely elongated forms, while very small and large cells are mostly compact (e.g., spherical or cubic). We show that cell shape has a strong effect on phytoplankton diversity, comparable in magnitude to the effect of cell volume, with both traits explaining up to 92% of the variance in phytoplankton diversity. Species richness decays exponentially with cell elongation and displays a log-normal dependence on cell volume, peaking for compact cells of intermediate volume. Our findings highlight different selective pressures and constraints on phytoplankton of different geometry and improve our understanding of the evolutionary rules of life.