Abstract
This 325-page supplement to Nova Hedwigia is a volume dedicated to the well-known and respected French diatom taxonomist René Le Cohu, subtitled ‘Celebrating the work and life of Prof. Dr. René Le Cohu on the occasion of his 80th birthday’. It is a collection of studies that deal with varied aspects of diatom research from systematics to palaeolimnology.
The book is organized as a collection of 20 papers sandwiched between two chapters that detail Prof. Le Cohu’s accomplishments. The introductory chapter consists of a description of the training and professional achievements of Prof. Le Cohu as well as a brief personal biography, while the final section summarizes the diatom taxa named by and after Le Cohu as well as a list of his publications. The introduction outlines the diversity of Prof. Le Cohu’s research and teaching interests throughout his career, and is followed by a diverse collection of papers that do justice to these interests. The assorted studies are signed by authors from 19 countries and include examinations of samples from over 15 countries in diverse geographic regions around the world. A number of new taxa are also described in the collection, including 1 new family, 1 new order, 3 new genera and 23 new species, of which 6 are taxa new to science that are dedicated to Prof. Le Cohu himself.
The large majority of the chapters are concerned with circumscribing individual species, or a number of taxa within a particular genus, but the volume also includes several community-level studies that assess taxonomic diversity with examples that apply classical approaches based on valve morphology as well as those that employ molecular methods using DNA. Most of the studies are concerned with freshwater sites, however, there are examples of studies from brackish and marine waters as well as of diatoms from soils. One chapter covers a decidedly unusual topic – newly identified epizoic taxa that were found living in association with the carapaces of marine turtles. While some ecological data appear scattered throughout, quantitative environmental data are generally lacking and the focus of the studies is essentially taxonomic. As one might expect in a volume largely dedicated to the morphology of diatom frustules, the majority of the chapters are beautifully illustrated with numerous images from both light photomicroscopy and scanning electron microscopy. Of specific interest to Holocene researchers, several studies make reference to palaeolimnological data, with three chapters presenting diatom (and other) stratigraphic diagrams. Of these, two are mainly concerned with showing the times at which particular diatom taxa of interest occurred in the past, while only one attempts to use these data to draw ecological inferences of past change, albeit without radiometric age constraint. As such, while there is certainly pertinent taxonomic information for those interested in Holocene diatom research, the volume contains few complete palaeolimnological studies.
The great diversity of research topics leads to what might be considered by some to be a certain lack of focus – while each paper is united by the common thread of diatom taxonomy, in many cases there is little else to link them thematically. Whether this characteristic is seen as a strength or a shortcoming is something that will likely be determined by the perspective of each individual reader. Regardless, this volume will be of interest to dedicated diatom taxonomists and ecologists, and Prof. Le Cohu will doubtless be gratified by its contents.