PHILIPPIA 13/2 S. 129-141 5 Tab. Kassel 2007 Alexandra Riethmüller*, Andreas Gründel** & Ewald Langer* The seasonal occurrence of aquatic Oomycetes in lakes and rivers of different water chemistry of Hesse, Germany Key words: classifi cation of water quality Zusammenfassung – Leptomitales – Saprolegniales - seasonal Wir verglichen das jahreszeitliche Vorkommen periodicity - trophic status aquatischer Oomycetes aus 27 verschiedenen Seewasserproben und aus Wasserproben von 12 verschiedenen Flüssen in Hessen von Abstract Herbst 2003 bis Sommer 2004. Um aqua- We compared the seasonal occurrence of tische Oomycetes aus den Wasserproben zu aquatic Oomycetes in 27 different lake water isolieren, haben wir die Ködermethode ange- samples and water samples of 12 different riv- wandt. Einige der Isolate konnten wir außer- ers from Hesse from autumn 2003 to summer dem kultivieren. Insgesamt konnten 27 Arten 2004. For isolating aquatic Oomycetes, the bait- aquatischer Oomycetes der Ordnungen Sap- ing method was used and some isolates could rolegniales, Leptomitales und Olpidiopsidales be cultivated additionally. A total of 27 species aus beiden Gewässertypen isoliert werden. Ein of aquatic Oomycetes belonging to the orders saprophytisches Isolat von Hyphochytrium (Hy- Saprolegniales, Leptomitales and Olpidiopsi- phochytriomycetes) und außerdem eine Art der dales could be isolated from both water body Plasmodiophoromycetes, Woronina polycystis, types, lakes and rivers. One saprophytic iso- konnten ebenso isoliert werden. Die Arten wur- late of Hyphochytrium (Hyphochytriomycetes), den untersucht und im Hinblick auf ihr Vorkom- and additionally one species of Plasmodiopho- men in verschiedenen Seen und/oder Flüssen romycetes, Woronina polycystis, was isolated diskutiert. 19 von 29 Arten (67 %) kamen ent- as well. The species were examined and dis- weder in Seewasser- oder in Flusswasser- cussed with respect to their occurrence in the proben vor. Die Arten Brevilegnia longicaulis different lakes and/or rivers. 19 of 29 species und Calyptralegnia ripariensis, welche bisher (67 %) only occurred in lake or in river water nur aus Bodenproben bekannt waren, wurden samples. Brevilegnia longicaulis and Calyptral- zum ersten Mal aus Wasser isoliert. Achlya ob- egnia ripariensis hitherto known only from soil, longata var. gigantica, B. longicaulis, Pythiopsis were fi rst found in water. Achlya oblongata var. irregularis und Saprolegnia furcata sind Neu- gigantica, B. longicaulis, Pythiopsis irregularis funde für Deutschland. Die zeitgleiche Unter- and Saprolegnia furcata are fi rst reported for Germany. The simultaneous observation of lim- * Universität Kassel, Fachgebiet Ökologie, Kassel, nochemical parameters of HLUG results in a Germany trophic status of the lakes and in a classifi cation ** Hessisches Landesamt für Umwelt und Geologie, of water quality of some rivers. Außenstelle Kassel, Germany 130 Alexandra Riethmüller, Andreas Gründel & Ewald Langer suchung von limnochemischen Parametern in Hesse as in the present publication. In this durch das Hessische Landesamt für Umwelt study, we aim to obtain an insight into the sea- und Geologie – HLUG ermöglicht eine Ein- sonal occurrence of further different aquatic schätzung der tropischen Situation der Seen Oomycetes of these water bodies. Species of und in eine Klassifi zierung der Gewässergüte aquatic Oomycetes have the potential as indi- von einigen der untersuchten Fließgewässer. cator organisms in the microscopical-biological characterisation of water in future. Observing organismic biodiversity of aquatic Oomycetes Introduction will be an approach in advancing our knowl- Species of aquatic Oomycetes occur in dif- edge of fundamental research on fungal diver- ferent water bodies all over the world and are sity of freshwater ecosystems. saprophytes on organic substances. Some species also act as parasites e. g. on different species of fi shes and then cause economi- Materials and methods cal problems in hatcheries. RIETHMÜLLER & We examined 27 lakes in cooperation with Hes- LANGER (2005b) focussed on the seasonal sisches Landesamt für Umwelt und Geologie occurrence of species of Saprolegniales and HLUG (table 1.1) and observed three different Leptomitales in Lake Aue and the River Fulda types of lakes: High Dams Lakes (deep, con- in Kassel (Hesse) with special consideration of stantly stratifi cated High Dam Lakes, polymic- fi shpathogenic species. tic Low Dams Lakes), lakes of ancient mining (stratifi cated ancient mining lakes, small an- The isolation of aquatic Oomycetes by a baiting cient mining lakes) and quarry ponds (deep method is easy and cheep and the identifi ca- stratifi cated quarry ponds, fl at unstratifi cated tion of species with newest available literature is quarry ponds, lakes smaller than 5 ha). Some practicable as well. Nevertheless, the research samples of the HLUG of the stagnant water on aquatic Oomycetes, especially in correla- bodies were collected and examined for the tion with statements on the trophic status of occurrence of the species in September 2003, lakes or the classifi cation of water quality of April and June 2004. Other samples could only rivers is still underrepresented. RIETHMÜLLER be collected and examined on aquatic Oomyc- (2000) examined 29 water samples from riv- etes in September 2003 or in April and June ers and lakes in Baden-Württemberg on the 2004. Additionally, High Dam Lake Ederstau- occurrence of Oomycetes and the samples see was examined at 3 sites in 2004 and at 4 were characterised by several water param- different sites in 2003. A total of 58 lake water eters. She focussed on two lakes differing in samples were collected together with HLUG their limnological character, and these lakes and examined. We also examined 12 rivers in also showed differences in biodiversity and cooperation with HLUG at different sites (table seasonal occurrence of species of Oomycetes. 1.2). The samples of HLUG of the running wa- Only few authors examined the trophic status ter bodies were collected and examined for the of the water body and correlated these results occurrence of aquatic Oomycetes in October with the biodiversity of aquatic Oomycetes. 2003, January, February, April, May and June RIETHMÜLLER & LANGER (2005a) also deter- 2004. Hence, a total of 102 river water samples mined the trophic status of the Aue Lake and was collected from HLUG and examined. the classifi cation of water quality of the River Fulda by limnochemical parameters obtained The HLUG annually surveys the water quality by simultaneous investigations of both water of the examined lakes and rivers in the region body types. of North Hesse. For the limnochemical exami- nations standard-methods and the guidelines RIETHMÜLLER et al. (2006) studied in detail of the Länderarbeitsgemeinschaft Wasser – the seasonal occurrence of the sewage fun- LAWA (1998, 2002) were used. The simultane- gus Leptomitus lacteus (ROTH) C. AGARDH in ous observations of limnochemical parameters the same stagnant and running water bodies of HLUG were used to conduct a limnochemical Occurrence of aquatic Oomycetes in Hesse, Germany 131 Table 1.1. Classifi cation of lakes, number of samples and examined sites, trophic status and middle index in 2003 and 2004 according to Hessisches Landesamt für Umwelt und Geologie – HLUG (2003, 2004). Classifi cation of lakes Sample Trophic status in 2003 Trophic status in 2004 Nr. of Nr. examined samples High Dam Lakes a) Deep, constantly stratifi cated High Dam Lakes (HDL) HDL Ederstausee, Edertal 10 middle index: 3,3 middle index: 2,8 Banfebucht 1_1 actual state: eutrophic 2 actual state: eutrophic 1 Scheid 1_2 middle index: 2,1 middle index: 2,3 Waldecker Bucht 1_3 actual state: mesotrophic actual state: mesotrophic Outfl ow of the lake 1_4 HDL Diemelstausee, middle index: 2,4 middle index: 2,5 2 3 Diemelsee-Heringhausen actual state: mesotrophic actual state: mesotrophic b) Polymictic Low Dams Lakes (LDL) middle index: 3,0 middle index: 3,2 LDL Affolderner See, Edertal-Affoldern 3 3 actual state: eutrophic 1 actual state: eutrophic 2 LDL Twistestausee, middle index: 2,9 middle index: 2,6 4 3 Bad Arolsen-Wetterburg actual state: eutrophic 1 actual state: eutrophic 1 LDL Antriftstausee, middle index: 3,1 5 1 Antrifttal-Seibelsdorf actual state: eutrophic 2 LDL Haunestausee, middle index: 4 6 1 Petersberg-Marbach actual state: polytrophic 1 middle index: 3,6 LDL Ibrastausee, Kirchheim 7 1 actual state: polytrophic 1 middle index: 4 LDL Silbersee, Breitenbach a. Herzberg 8 1 actual state: polytrophic 1 Lakes of ancient mining a) Stratifi cated ancient mining lakes (amL) middle index: 1,1 middle index: 1,5 amL Borkener See, Borken 9 3 actual state: oligotrophic actual state: oligotrophic amL Singliser See, Borken-Gombeth 10 < pH5, acidifi ed < pH5, acidifi ed 3 amL Exbergsee, middle index: 1,8 11 1 Großalmerode-Epterode actual state: mesotrophic middle index: 2 amL Goldbergsee, Malsfeld-ostheim 12 1 actual state: mesotrophic amL Zimmersroder See, middle index: 1,7 13 1 Neuental-Zimmersrode actual state: mesotrophic middle index: 1,6 amL Hellkopfsee, hessisch Lichtenau 14 1 actual state: mesotrophic amL Silbersee Frielendorf, middle index: 1,8 15 2 Frielendorf-Allendorf actual state: mesotrophic b) Small ancient mining lakes (samL) middle index: 2,3 samL Neuenhainer See, Neuental 16 2 actual state: mesotrophic samL Lake Stellbergsee, middle index: 2,7 17 2 Guxhagen-Wollrode actual state: eutrophic samL Guckaisee, middle index: 2,6 18 2 Poppenhausen-Rodholz actual state: eutrophic 1 132 Alexandra Riethmüller,