Index Fungorum, Species Fungorum and MycoBank are the key fungal nomenclature and taxonomic databases that can be sourced to find taxonomic details concerning fungi, while DNA sequence data can be sourced from the NCBI, EBI and UNITE databases. Nomenclature and ecological data on freshwater fungi can be accessed on http://fungi.life.illinois.edu/ , while http://www.marinespecies.org/provides a comprehensive list of names of marine organisms, including information on their synonymy. Previous websites however have little information on marine fungi and their ecology, beside articles that deal with marine fungi, especially those published in the nineteenth and early twentieth centuries may not be accessible to those working in third world countries. To address this problem, a new website www.marinefungi.org was set up and is introduced in this paper. This website provides a search facility to genera of marine fungi, full species descriptions, key to species and illustrations, an up to date classification of all recorded marine fungi which includes all fungal groups (Ascomycota, Basidiomycota, Blastocladiomycota, Chytridiomycota, Mucoromycota and fungus-like organisms e.g. Thraustochytriales), and listing recent publications. Currently, 1257 species are listed in the marine fungi website ( www.marinefungi.org ), in 539 genera, 74 orders, 168 families, 20 classes and five phyla, with new taxa continuing to be described. The website has curators with specialist mycological expertise who help to provide update data on the classification of marine fungi. This article also reviews knowledge of marine fungi covering a wide range of topics: their higher classification, ecology and world distribution, role in energy transfer in the oceans, origin and new chemical structures. An updated classification of marine fungi is also included. We would like to invite all mycologists to contribute to this innovative website.

Summary: Chytridiomycota, often referred to as chytrids, can be virulent parasites with the potential to inflict mass mortalities on hosts, causing e.g. changes in phytoplankton size distributions and succession, and the delay or suppression of bloom events. Molecular environmental surveys have revealed an unexpectedly large diversity of chytrids across a wide range of aquatic ecosystems worldwide. As a result, scientific interest towards fungal parasites of phytoplankton has been gaining momentum in the past few years. Yet, we still know little about the ecology of chytrids, their life cycles, phylogeny, host specificity and range. Information on the contribution of chytrids to trophic interactions, as well as co‐evolutionary feedbacks of fungal parasitism on host populations is also limited. This paper synthesizes ideas stressing the multifaceted biological relevance of phytoplankton chytridiomycosis, resulting from discussions among an international team of chytrid researchers. It presents our view on the most pressing research needs for promoting the integration of chytrid fungi into aquatic ecology.

Little is known about the role of chemotaxis in the location and attachment of chytrid zoospores to potential diatom hosts. Hypothesizing that environmental stress parameters affect parasite-host recognition, four chytrid-diatom tandem cultures (Chytridium sp./Navicula sp., Rhizophydium type I/Nitzschia sp., Rhizophydium type IIa/Rhizosolenia sp., Rhizophydium type IIb/Chaetoceros sp.) were used to test the chemotaxis of chytrid zoospores and the presence of potential defense molecules in a non-contact-co-culturing approach. As potential triggers in the chemotaxis experiments, standards of eight carbohydrates, six amino acids, five fatty acids, and three compounds known as compatible solutes were used in individual and mixed solutions, respectively. In all tested cases, the whole-cell extracts of the light-stressed (continuous light exposure combined with 6 h UV radiation) hosts attracted the highest numbers of zoospores (86%), followed by the combined carbohydrate standard solution (76%), while all other compounds acted as weak triggers only. The results of the phytochemical screening, using biomass and supernatant extracts of susceptible and resistant host-diatom cultures, indicated in most of the tested extracts the presence of polyunsaturated fatty acids, phenols, and aldehydes, whereas the bioactivity screenings showed that the zoospores of the chytrid parasites were only significantly affected by the ethanolic supernatant extract of the resistant hosts.

The unconsolidated sediment of intertidal mudflats constitutes a highly unstable environment, due to continuously changing water levels and currents, as well as temporary exposure to the air. As a consequence, diatoms inhabiting marine intertidal areas are subjected to wide variations in temperature, surface light intensity and salinity due to exposure at low tide. In order to determine the adaptive potential of these organisms, cultures of 25 benthic marine diatom species present in the Solthörn tidal flat in the years 2008/2009 were chosen to study the effect of different abiotic conditions. As expected, the interspecific growth rates between individual species varied considerably, from 0.181 d⁻¹ [Gyrosigma peisonis (Grunow) Hustedt] to 0.861 d⁻¹ [Navicula phyllepta (Kützing)], while the intraspecific growth rates were only slightly influenced by most of the tested variables. In detail, individual effects were found for different substrates (mixed glass beads, mixed sands, none), nitrogen sources (nitrate, urea, ammonium), photon flounce rates (400, 800 and 1200 μmol photons m⁻² s⁻¹) and day lengths (light:dark cycle, 8:16, 12:12, 16:8 h); whereas variations in salinity from 20 to 35 PSU and temperature from 10 to 30 °C did not show any influence on benthic diatom growth. By contrast, extreme temperatures (4, 40 °C) and salinities (10, 40 PSU) led to significant decreases in the growth rates of most species. Only minor effects on the growth of Navicula spp. in the 10 PSU treatments were distinguishable, e.g., N. digito-radiata (Gregory) Ralfs. All in all, the adaptation potential of the Solthörn tidal flat isolates in relation to the tested environmental ranges was appreciable, suggesting special intracellular adaptation processes that provide possible explanations for the species’ insensibility towards environmental variations and distinct differences in the diatom assemblages.