The present volume contains 21 papers presented at the Seventh International Chrysophyte Symposium 2008 spanning a broad range of topics on chrysophytes and related heterokont organisms. The contributions include ones on ecology, taxonomy, floristic works, phylogeny and evolution, molecular biology, physiology and paleolimnology. Of special interest are a group of papers that use geometric morphometric analyses to address taxonomic, biogeographic and phylogenetic questions related to chrysophytes and other microalgae. Ecological and floristic contributions include ones on lakes from the polar Ural Mountains, the Mesopotamia region of South America, the Pine Barrens of southern New Jersey, and the Swiss Alps. Gene sequences are used to study hidden diversity in Synura and differences between two geographically distinct Heterosigma isolates, and production of polyunsaturated aldehydes is examined in Thalassiosira. Other contributions include ones on mixotrophy, biofilm dynamics, the recent invasion of Mallomonas pseudocoronata into lakes in Sweden, use of cysts in climate change research, paleolimnology of eastern North American lakes, an evaluation of the age of the Hueyatlaco early man site in Mexico, a comparison of the architecture of Mallomonas scale coverings between modern and 40 Ma specimens and bloom dynamics. Papers outlining the establishment of a Wiki for chrysophyte cysts, an on-line database for Eocene chrysophyte fossils, and ideas for preserving specimens in museums round out the volume.

Members of the classes Chrysophyceae and Synurophyceae known as scaled chrysophytes are often used for biomonitoring and palaeoecological studies because they are efficient indicators of environmental conditions. They are heterokonts being relatives of among others the diatoms.

International Chrysophyte Symposia (ICS) have been held since 1983. Fifty scientists attended at the Seventh ICS in New London. They spoke on examination of chrysophytes as well as other protists providing insights into novel methods. Their findings are published in this volume that is started with a meeting report by R. A. Andersen who gives account of the symposium sharing his experiences and feelings with us.

The book has five main parts according to topics of the articles. The first chapter titled “Taxonomy and geometric morphometrics” contains four papers demonstrating what the landmark-based geometric morphometrics can be applied to. This method was proved to be a powerful tool for analysis of phenotypic plasticity of Synurophyceae species based on shape variations of silica scales as well as for examination of symmetry and allometry of the zygnemophycean Micrasterias rotata.

Chrysophytes are represented in the sedimentary records of lakes and rivers by siliceous scales and resting stages known as stomatocysts. Studies written in the “Paleolimnology” part demonstrates how stomatocysts and other microfossils can be used for indicating past and present environmental conditions. Mallomonas porifera was originally described based on isolated scales from Middle Eocene sediments. Siver and Wolfe reconstructed the whole cell of this fossil organism from fractured mudstone samples. An interesting study shows determination of the age and palaeoenvironment for artefacts found at an early man site Hueyatlaco, based on diatoms and chrysophytes.

Section “Ecology and biogeography” includes exploration of chrysophyte flora in shallow, acidic water bodies in New Jersey, rivers in Mesopotamia region of Argentina and glacial lakes of the Polar Ural. The latter is important because future effects of global climate changes and local anthropogenic ones can be especially significant in the Arctic region. In the same chapter the appearance of Mallomonas pseudocoronata is reported from Sweden. This organism previously occurred at only a restricted area outside North America. Holen examined the phenomenon of myxotrophy, the nutritional strategy of combination of photosynthesis and heterotrophy in the case of two chrysophycean species. Similar experiments were conducted by Watson and McCauley investigating whether light and bacteria were substitutable energy sources for chrysophyte blooms.

The fourth part consists of four articles touching fields of biochemistry, physiology and molecular biology. Production of fatty acid-derived polyunsaturated aldehydes negatively affects the grazers of algae, and in the case of Thalassiosira rotula this activity was proved to change under different culture conditions. Didymosphenia geminata is an invasive species of freshwater ecosystems in many areas. Analysis of its biofilm dynamics performed with different microscopical techniques revealed that bacterial assemblage attached to this diatom enhanced its adhesion to substrates. Comparison of complete mitochondrial genome sequences unveiled differences between two geographically distinct Heterosigma akoshiwo (Raphidophyceae) strains, and analysis of their mitochondrial genes determined their phylogenetic position. Examination of ITS region revealed that Synura petersenii was rather a complex than only one species, and this result was strengthened by traditional and geometric morphometric study.

The last section is about collections and databases emphasising the importance of sharing the results. This is the aim of Stom@ocysts, the web-based tool developed for facilitating stomatocyst classification and the online Giraffe Pipe database for siliceous microfossils from a Middle Eocene maar lake. Within a research note Hamilton reviews the state of chrysophyte voucher collections and methods for preserving specimens.

This volume gives insights into morphology, palaeology, ecology, biogeography, physiology and molecular biology of chrysophytes and related algae. It not only displays the results but also provides powerful examination tools. The value of this book is increased by images performed with using different kinds of microscopical techniques. This book can be recommended to everyone interested in either the chrysophytes, or new and useful methods.

M. DULEBA

Acta Botanica Hungarica 53 (3-4), 2011, p. 447-449