NVKD studiedagen 31 mei 2 juni 2012 Koeman en Bijkerk BV Telefoon: 050-820 0018 Oosterweg 127 r.bijkerk@koemanenbijkerk.nl 9751 PE Haren (Groningen) http://www.koemanenbijkerk.nl Geachte NVKD leden, Dit jaar vindt de jaarlijkse studiebijeenkomst van de NVKD sinds lange tijd weer in het noorden van Nederland plaats, namelijk in Haren, Groningen, bij Koeman en Bijkerk. Dit jaar hebben wij geen speciaal thema gekozen maar in plaats hiervan een aantal bijzondere sprekers uitgenodigd die over hun onderzoek zullen berichten. De eerste dag, donderdag 31 mei, staat in het teken van de derde taxonomische workshop (aanvang 10.30 u.). De eerste twee workshops in Aalst (2010) en Lelystad (2011) waren een groot succes en het NVKD bestuur heeft daarom besloten deze traditie voort te zetten 1. Op vrijdag 1 juni is de jaarlijkse lezingendag met een gevarieerd programma. Op zaterdag 2 juni is een bijzondere (vaar)excursie gepland. Zoals altijd zijn er geen kosten verbonden aan de lezingendag. Voor de deelname aan de taxonomische workshop op donderdag 31 mei bedragen de kosten 50,00 (betalingsbewijs wordt verstrekt op 31 mei). Thema van de workshop zijn Fragilaria construens s.l. en Fragilaria pinnata s.l. Meebrengen: eigen slides met probleemschaaltjes en indien mogelijk de eigen vertrouwde microscoop. Speciale problemen met deze soortgroepen kunt u van tevoren aanmelden bij Bart Van de Vijver, bij voorkeur voor 30 april 2012. Ik wens iedereen inspirerende studiedagen! Holger Cremer Voorzitter NVKD 1 De studieboeken van de vorige taxonomische workshops kunt u vinden op de NVKD website www.diatom.nl.
Programma 1 juni: lezingendag 10.00 u. Ontvangst (koffie, thee) 10.25 u. Opening door Holger Cremer, voorzitter NVKD. 10.30 10.50 u. Ronald Bijkerk (Koeman en Bijkerk): Introductie Koeman en Bijkerk. 10.50 11.50 u. Peter Kroth (Universität Konstanz, Duitsland): The peculiar molecular biology of diatoms. 11.50 12.30 u. Ledenvergadering NVKD. De agenda is bijgevoegd. 12.30 Lunch. 13.45 14.15 u. Frank Schuren (TNO, The Netherlands): New Biology: the HydroChip and its added value in increasing knowledge on water ecology. 14.15 14.45 u. Ellen Weerman (HAS Den Bosch, The Netherlands): Diatoms as landscape engineers. 14.45 u. Pauze 15.00 15.30 u. Ines Tavernier (Ghent University, Belgium): Holocene climate variability and its effect on ice sheet dynamics and lacustrine microbial communities in Lützow Holm Bay (East Antarctica). 15.30 16.00 u. Kateřina Kopalová (Charles University Prague, Czech Republic): The freshwater diatom flora from Ulu Peninsula (James Ross Island, NW Weddell Sea, Antarctica). 16.00 16.30 u. Alejandra Goldenberg-Vilar (University of Amsterdam, The Netherlands): Spatial patterns of diatoms in degraded peatlands: comparison of three ecologically contrasting systems. 16.30 16.40 u. Bart Van de Vijver (National Botanic Graden of Belgium): Encyonopsis neerlandica, a new freshwater diatom from moorlandpools in the Netherlands. 16.40 u. Nawoord en sluiting door de voorzitter NVKD.
Agenda ledenvergadering NVKD op vrijdag 31 mei 2012 bij Koeman en Bijkerk te Haren, Nederland 1. Opening, vaststellen agenda, mededelingen. 2. Verslag ledenvergadering 13 mei 2011 in Lelystad, Nederland (bijgevoegd). 3. Kort jaaroverzicht 2011 (secretaris). 4. Toelichting financieel jaaroverzicht 2011 en begroting 2012 (penningmeester, P. Vos). 5. Verslag kascommissie over 2011 en verkiezing nieuw lid van de kascommissie (Jaco van der Wal treedt af, Marianne Thannhauser blijft nog één jaar aan). Op de vergadering wordt een nieuw kascommissielid gekozen. 6. Verkiezing nieuwe bestuursleden. Volgens het aftreedrooster is algemeen bestuurslid en erelid Herman van Dam aan de beurt af te treden. Herman stelt zich graag opnieuw verkiesbaar. Tegenkandidaten kunnen zich melden bij de voorzitter of de secretaris voor de ledenvergadering, bij voorkeur schriftelijk. 7. Web-site NVKD. B. Pex 8. Taxonomische diatomeeën workshop: evaluatie en toekomst (visie Bart Van de Vijver). 9. ISDR symposium Gent (Bart). 10. Web-based taxonomische site (Bart). Bart Van de Vijver en Frans Kouwets verwachten eind dit jaar met een website te komen over taxonomie van diatomeeën van de lage landen. 11. Diatomededelingen: nieuws, indienen kopij, deadline 12. Rondvraag. 13. Sluiting.
VERSLAG LEDENVERGADERING NVKD 13 mei 2011 bij de Waterdienst te Lelystad, Nederland 1. Opening, vaststellen agenda, mededelingen. Bert Pex afwezig wegens familieomstandigheden. Christine Cocquyt is afwezig wegens vakantie. 2. Verslag ledenvergadering 23 april 2010 in Aalst, België (bijgevoegd). Geen opmerkingen. Dit verslag is ook te lezen in Diatomededelingen 34, december 2010. 3. Kort jaaroverzicht 2010 (secretaris). Geen overlijdensberichten binnen de vereniging. Jolanda van Iperen, vanaf het begin lid van de vereniging, heeft opgezegd wegens verandering van werkkring. Het ledenaantal bedraagt 58 leden en 9 instituten. Nog even terugkijkend hadden we een fantastische bijeenkomst bij de Vlaamse Milieu Maatschappij in Aalst, België. Een uitgebreid verslag hiervan is opgenomen in Diatomededelingen 34. In 2010 was de eerste workshop taxonomie door Bart Van de Vijver over Achnanthidium. Deze was zeer succesvol en wordt vervolgd. 26 november 2010 heeft het bestuur vergaderd in Beegden bij Bert Pex ter voorbereiding van de bijeenkomst in Lelystad 2011, waarbij tevens het 25-jarig bestaan werd voorbereid. In december 2010 is Diatomededelingen 34 verschenen, samengesteld door Holger Cremer en Christine Cocquyt. 4. Toelichting financieel jaaroverzicht 2010 en begroting 2011 (penningmeester, Peter Vos). Peter Vos licht toe dat de vereniging financieel gezond is en verzoekt de leden na te denken over activiteiten die kunnen worden ondersteund. 5. Verslag kascommissie en over 2010 en verkiezing nieuw lid van de kascommissie (Adrienne Mertens treedt af, Jaco van der Wal blijft nog één jaar aan). Op de vergadering wordt een nieuw kascommissielid gekozen. Adrienne Mertens doet namens de kascommissie verslag over het financieel beheer van 2010 met als conclusie dat alles in orde is bevonden. De penningmeester wordt bedankt voor zijn werk en gedechargeerd over 2010. Adrienne Mertens treedt af als kascommissielid; Jako van der Wal blijft nog 1 jaar aan; als nieuw kascommissielid heeft Marianne Thannhauser zich aangeboden. 6. Web-site NVKD. Bert Pex Bij afwezigheid van Bert wordt dit punt niet verder behandeld; alle leden kunnen veel (en steeds meer) informatie vinden op de website www.diatom.nl.
7. Taxonomische diatomeeën workshop: evaluatie en toekomst. De taxonomische workshop van Bart Van de Vijver is bijzonder in de smaak gevallen en zeker voor herhaling vatbaar. Bart wil graag suggesties ter verdere verbetering van deze activiteit. Iedereen kan zich bij hem melden met ideeën. Bart wil dit uitbouwen tot een regelmatig terugkerende activiteit voor de leden. 8. Verkiezing nieuwe bestuursleden. Bart Van de Vijver en Christine Cocquyt treden beiden af. Bart heeft te kennen geven wel in het bestuur actief te willen blijven als conservator en redacteur. Christine zal niet terugkeren in het bestuur. Voor Christine Cocquyt wordt als algemeen bestuurslid voorgedragen: Caroline Souffreau. Als nieuwe voorzitter, opvolger van Bart Van de Vijver, wordt het huidige bestuurslid Holger Cremer voorgedragen. Christine Cocquyt heeft te kennen gegeven te willen stoppen met haar werk in het bestuur van de NVKD en treedt af. Herman van Dam houdt een korte toespraak waarin nog eens gememoreerd wordt hoeveel Christine voor de vereniging heeft betekend. Voor haar in de plaats wordt Caroline Souffreau in het bestuur verwelkomd. Bart Van de Vijver treedt af als voorzitter en Holger Cremer wordt gekozen als nieuwe voorzitter. Bart blijft als bestuurslid wel actief. Het bestuur heeft nu de volgende samenstelling: voorzitter en productie Diatomededelingen: Holger Cremer secretaris: Gert van Ee penningmeester: Peter Vos conservatrix, bibliotheek NVKD: Caroline Souffreau webmaster: Bert Pex Taxonomie en redacteur Diatomededelingen: Bart Van de Vijver Algemeen bestuurslid: Herman van Dam 9. Rondvraag. Jako van der Wal merkt op dat de email adressen niet kloppen; zijn emailadres was verouderd. Reactie bestuur: de leden worden dringend verzocht tijdig veranderingen door te geven aan de secretaris en/of penningmeester. Er wordt komend jaar aan gewerkt de ledenlijst geheel bij te werken. 10. Sluiting.
ABSTRACTS
Spatial patterns in diatom diversity in peatlands: comparison of three ecologically contrasting systems ALEJANDRA GOLDENBERG VILAR 1, H. VAN DAM 2, G. VAN EE 3, R. VAN LEUKEN 4, A. KREIKE 4, E. NAT 4, H.G. VAN DER GEEST 1 & W. ADMIRAAL 1 1 Department of Aquatic Ecology and Ecotoxicology, IBED, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands (a.goldenbergvilar@uva.nl) 2 Adviseur Water en Natuur. P.O. Box 37777, 1030 BJ Amsterdam, The Netherlands 3 Hoogheemraadschap Hollands Noorderkwartier, P.O. Box 29, 1700 AA Heerhugowaard, The Netherlands 4 Stichting Waterproef. P.O. Box 43, 1135 ZG Edam, The Netherlands Diatoms are widely used in ecological monitoring because of their high sensitivity to environmental disturbances, but knowledge on the spatial patterns in diversity is virtually lacking. However, in Dutch peatlands, the artificial network of canals and ditches, with distinct chemical and hydromorphological gradients, creates a mosaic of diatom communities. To understand these distribution patterns it is essential to gain insight in the underlying mechanisms that cause these patterns. In general, the similarity in species composition between ecological communities is typically decreasing with increasing distance. For macroorganisms, this phenomenon is often quantified using distance decay relationships and species area relationships (SAR) and is often explained by the occurrence of environmental gradients and the spatially limited dispersal capacity of the species involved. In the last years, an intensive scientific debate arose whether microorganisms such as diatoms exhibit similar patterns. Available scientific studies show that generalizations across all unicellular organisms studied so far are unwarranted as they exhibit wide variability. The present study attempts to identify the mechanisms that generates diatom distribution patterns according to chemical and hydromorphological gradients by the comparison of three peatland areas in The Netherlands: Wormer and Jisperveld, Oostzanerveld and Naardermeer. The sampling follows a nested and spatially explicit design along six kilometers sampling tracks. The knowledge obtained in the present study is expected to be applied in a GIS species distribution model and will provide ecological background for practical issues such the selection of sampling points and sampling units for biological monitoring.
The freshwater diatom flora from Ulu Peninsula (James Ross Island, NW Weddell Sea, Antarctica) KATEŘINA KOPALOVÁ 1,3, J. VESELÁ 2, J. ELSTER 2,3, L. NEDBALOVÁ 1,3, M. DE HAAN 4, J. KOMÁREK 2,3 & B. VAN DE VIJVER 4 1 Charles University in Prague, Faculty of Science, Department of Ecology, Viničná 7, CZ- 12844 Prague 2, Czech Republic (K.Kopalova@hotmail.com) 2 University of South Bohemia, Faculty of Science, Department of Botany, Na Zlaté stoce 1, CZ-37005 České Budějovice, Czech Republic 3 Academy of Sciences of the Czech Republic, Institute of Botany, Section of Plant Ecology, Dukelská 135, CZ-37982 Třeboň, Czech Republic 4 National Botanic Garden of Belgium, Department of Bryophyta & Thallophyta, Domein van Bouchout, B-1860 Belgium A few years ago, a detailed study on the taxonomy of freshwater diatoms from James Ross Island has been started. James Ross Island (64 10 S, 57 45 W) is situated in the northwestern part of the Weddell Sea, close to the northern tip of the Antarctic Peninsula. Only the northern part of the island (=Ulu Peninsula) is ice-free. The remaining 75% of the island is covered with a permanent icecap. In 2006, a new Czech Antarctic station (J. G. Mendel station) was finally constructed on the island and during the austral summers between 2004 and 2009 a large number of samples was collected from seepage areas, streams and lakes. Most recently, during the austral summer of 2012, moss samples have also been collected. The aim of this study is to investigate the diatom communities living in these habitats in relation to the ecological factors determining their composition, diversity and presence. Until recently, most of the non-marine Antarctic diatom species were believed to have a cosmopolitan nature, mainly due to the use of non-appropriate taxonomic literature. Only very few of the reported species showed an Antarctic distribution. The results of our study contradict entirely this statement and present a mainly specific maritime Antarctic flora. More than 100 diatom taxa have been identified during the survey. Following detailed morphological research, based on light and scanning electron microscopy, several species have been described as a new for science, such as the endemic Eolimna jamesrossensis, Luticola truncata Kopalová & Van de Vijver and Diadesmis inconspicua Kopalová & Van de Vijver while several others including Chamaepinnularia gerlachei Van de Vijver & Sterken, Craticula antarctica Van de Vijver & Sabbe and Luticola austroatlantica were described from James Ross Island but also occur on neighboring islands. Recently, five new Luticola species have been recorded in the lake samples and also benthic diatoms from seepages and streams were published. The work is however not finished as is proven by a recent survey of the genus Diadesmis on several islands in the southern Atlantic and southern Indian Ocean showing, that the taxonomy of this genus needs a thorough revision. During the presentation, the morphology of some of the new species will be illustrated and we will discuss the results of the ecological analysis using multivariate analysis. Based on our results we were able to characterize ecologically several typical diatom communities with specific conductance, soluble reactive phosporus, alkalinity and total phosphorus as main determining parameters. The biogeographical relationship of the diatom flora of James Ross Island with other Antarctic localities is highlighted.
The peculiar molecular biology of diatoms PETER KROTH Department of Biology, University of Konstanz, Germany Algae represent a large, phylogenetically diverse and morphologically variable group of organisms comprising tiny picoplankton as well as large kelp. Algal research to date experiences a strong boost from actual genome projects and the development of molecular tools to study algae and algal processes like large scale transcription analyses, transformation techniques and gene silencing approaches. For diatoms there are two genomes available (for the pennate Phaeodactylum tricornutum and the centric Thalassiosira pseudonana) including two more genomes close to publication (Pseudonitzschia sp. and Fragilariopsis cylindrus). Diatoms are very interesting organisms for various reasons, including their ecological relevance, their silicified cell walls and their peculiar evolution by secondary endocytobiosis (the incorporation of a eukaryotic alga into a eukaryotic host cell, followed by transformation of the endosymbiont into a plastid). Especially the latter process resulted in various differences with respect to the physiology and cell biology of these algae when compared to green algae and land plants. Comparative analyses revealed relocated metabolic pathways, modified regulation processes and unexpected proteins: (i) In diatoms very few enzymes of the Calvin cycle are redox regulated by small proteins termed thioredoxins that function as a light switch for CO2 fixation by reducing target enzymes. (ii) Essential pathways like the oxidative pentose phosphate together with nucleotide synthesis pathways have been reallocated in diatoms. (iii) As a consequence, additional plastidic translocators for nucleotides and carbohydrates were established. (iv) Enzymes of the second half of glycolysis can be found in the cytosol, in the plastids as well as in the mitochondria. (v) We do have first indications that enzymes might be located in the periplastidic space of diatoms, including an NADP-dependent thioredoxin reductase and a phosphogluconate dehydrogenase. (vi) Diatoms also show a very unusual distribution of carboxylating and decarboxylating enzymes.
New Biology: the HydroChip and its added value in increasing knowledge on water ecology FRANK H.J. SCHUREN & H. CREMER TNO Earth, Environmental and Life Sciences, Zeist and Utrecht, The Netherlands The water quality in Europe is enormously under pressure by various interfering chemical, physical, and biological stressors. An acceptable water quality is, however, essential for the persistence of aquatic ecosystems and also has wide-ranging socio-economic impacts. In Europe water policy and water pollution control is embedded in a number of environmental directives, e.g. the European Water Framework Directive, and the Bathing Water and Drinking Water Directives. Siliceous algae, predominantly diatoms, and blue-green algae play a prominent role in these directives and thus are an essential component of biomonitoring as diatoms are important indicators of water quality, reacting sensitive and fast to environmental change. Traditional diatom monitoring includes regular sampling and controlling of diatom communities using light microscopy techniques. However, this approach is limited by a combination of financial resources and analysis capacity, long running time, and chance of erroneous morphological diagnosis. In order to forestall these disadvantages we are developing the DNA-based HydroChip monitoring tool. This new application, based on DNA microarray technology, will allow an automatic, fast, efficient, standardized and reliable assessment of the algal (diatom) flora at minimal costs. The possibility of rapid low-cost analyses will also permit early warning of and possible direct measures against developing deleterious water conditions. We make use of sequence variations in the 18s rrna encoding gene as a barcode marker. Development of this diagnostic tool will be presented in more detail including current limitations in the diatom world (lack of sequence information, lack of pure cultures). First habitat typing tests with a prototype of the HydroChip carrying the barcodes of more than 130 diatom species applied to a large set of substrate samples (reed and small stones) collected in various water types in the Netherlands show a clear consistency between traditionally counted samples and those analyzed with the new molecular tool. Development and application of powerful barcoding techniques for water quality issues will promote uniform ecological monitoring across the Netherlands and, potentially across Europe.
Holocene climate variability and its effect on ice sheet dynamics and lacustrine microbial communities in Lützow Holm Bay (East Antarctica) INES TAVERNIER 1, E. VERLEYEN 1, D.A. HODGSON 2, A. JACQUES 1, S. IMURA 3, S. KUDOH 3, K. SABBE 1 & W. VYVERMAN 1 1 Protistology and Aquatic Ecology - Ghent University, Ghent, Belgium 2 British Antarctic Survey, Cambridge, United Kingdom 3 National Institute of Polar Research, Tokyo, Japan Of the global ice sheets, the Antarctic ice sheet has least field data to constrain its past volume and contribution to global sea-level change since the Last Glacial Maximum. Moreover, little is known about the timing of deglaciation in vast sectors of the continent and ice sheet responses to Holocene climate variability, despite this information being critical for estimating the ice sheet s contribution to future sea-level changes in a warming world. In order to minimize these uncertainties, we developed a new relative sea-level (RSL) curve for Lützow-Holm Bay (East Antarctica, EA) using marine to freshwater transitions in sediment cores from isolation lakes. We combined this with a study of the deglaciation history by radiocarbon dating transitions from glaciogenic to organic-rich sediments in glacial lakes. Reconstructions were also made of past changes in the regional climate-related moisture balance and temperature-dependent lake primary productivity using biological and sedimentological proxies. We focused on West Ongul Island and Skarvsnes, a peninsula 60 km distant. On West Ongul Island, the Holocene RSL maximum was below 13 m above sealevel (a.s.l.). RSL fell from this maximum at a rate of 8.1 mm/yr between 3945 and 3575 cal. yr BP to 2.8 mm/yr during the past 3575 calibrated years. On Skarvsnes, the RSL shows a more complex history. The Holocene RSL maximum could not be determined exactly, but was above 28 m a.s.l. between 5726 and 2692 cal. yr BP. RSL fell at 17.3 mm/yr between 2692 and 1155 cal. yr BP, dropping rapidly to 1.3 mm/yr during the past 1155 years. The RSL changes on West Ongul Island are in agreement with previous findings from the region. By contrast, the RSL curve for Skarvsnes differs from previous reconstructions. The patterns may be explained by increasing the modeled maximum ice thickness during the Holocene in this region and by imposing a subsequent melting event, possibly during the mid to late Holocene warm period. This climate anomaly has been inferred from ice, lake and marine sediment cores in EA between c. 4 and 2 ka BP and was similarly present in a sediment core from nearby Lake Ô-Ike between c. 2708 and 1753 cal. yr BP. A modeling approach using a suite of glacio-isostatic adjustment models will be used to confirm or reject this hypothesis of late Holocene regional ice mass loss. If correct this will imply that the East Antarctic ice sheet in this region is probably less stable than previous models and field data have suggested.
Diatoms as landscape engineers ELLEN WEERMAN HAS University of Applied Sciences, s-hertogenbosch, The Netherlands In this presentation I will present the main conclusions from my PhD research conducted at the Netherlands Institute of Ecology in Yerseke (now NIOZ-CEME). During spring the landscape of muddy intertidal flats can exhibit a striking spatial pattern of hollows and diatom covered hummocks. The interaction between diatoms, water drainage and sedimentation processes was found to be a key determinant of the formation of a regular landscape of diatom-covered hummocks and water-filled hollows. These spatial patterns were found to affect ecosystem functioning by increasing total diatom content and net sedimentation on the scale of the entire mudflat. Subsequently, I show that top-down control by benthic herbivores has a major influence on landscape formation, affecting benthic phototrophic biofilms at microbial scale (µm) as well as on intertidal flat scale (m). Herbivores controlled pattern formation following the seasonal collapse of the diatom biofilm patterns and in the laboratory ciliate grazers were found to decrease clustering in the micro-scale landscape of photrophic biofilms. Top-down control did not only affect landscape formation, but also increased net primary production (but not biomass), which was validated by laboratory experiments. Analysis of changes in the spatial characteristics of spatial patterns as they degraded due to increased grazing intensity revealed predictable changes in their spatial configuration which point out that there is a potential use of spatial patterns as an indicator for rapid shifts to a degraded state.
Encyonopsis neerlandica, a new freshwater diatom species (Bacillariophyta) from moorlandpools in The Netherlands BART VAN DE VIJVER 1*, G.L. VERWEIJ 2, J. VAN DER WAL 3 & A. MERTENS 4 1 National Botanic Garden of Belgium, Department of Cryptogamy, Domein van Bouchout, B- 1860 Meise, Belgium (vandevijver@br.fgov.be) 2 Koeman en Bijkerk n.v., Postbus 111, Nl-9750 AC Haren, The Netherlands 3 AQUON-Boxtel, Postbus 298, Nl-5280 AG Boxtel, The Netherlands 4 Grontmij B.V., Department Water, Team Ecology, Postbus 95125, NL-1090 HC Amsterdam, The Netherlands A new cymbelloid diatom species, Encyonopsis neerlandica sp. nov., is described from several moorland pools from The Netherlands. The new species belongs to the complex of species around E. microcephala. Based on Light and detailed Scanning Electron Microscopy, the morphology of the new species is discussed and compared to similar species from this complex. Encyonopsis neerlandica is characterized by its rather large valve dimensions, the narrowly to clearly lanceolate valve outline with convex to weakly convex margins and rostrate to capitate apices. The distal raphe fissures are ventrally deflected. There is a clear difference between the rounded areolae near the valve margin and the transapically elongated areolae near the axial area. Notes on the ecology of the species are added.