BSSP 2001 Spring Meeting - Contributed Paper Abstracts
DEVELOPMENT OF A WEB-BASED GUIDE TO MARINE PLANKTONIC CILIATES
Michaela C Strüder-Kypke and David JS Montagnes, Port Erin Marine Laboratory, University of Liverpool, Port Erin, Isle of Man IM9 6JA.
To understand the diversity and ecology of marine plankton, protist species often need to be determined precisely, but identification is a challenge for ecologists. Furthermore, there is no comprehensive taxonomic guide to marine planktonic protists. The internet is an ideal tool to provide information about protist biodiversity; we indicate how it can be used as a guide to identify taxa in general. Web-based guides have several advantages compared to books: they can be modified and expanded easily and at any time; the distribution is rapid and simple; and a search engine within a web site or data base can replace the dichotomous key. Furthermore, such guides can be downloaded onto the computer hard drive and used offline and print versions can be produced, providing information when computers are not available. As part of the NERC "Marine Productivity programme", we are developing a guide to identify marine planktonic ciliates collected during routine ecological sampling. The guide is primarily aimed at ecologists, but we also hope to provide useful data for students, enthusiastic amateur naturalists and experts in ciliate taxonomy. We are assembling an illustrated database of planktonic ciliate taxa by reviewing the literature and supplementing these with new data. The descriptions are based on Lugol's fixed samples and combine the characters visible in this material with more specific taxonomic features (e.g. SEM, protargol, and live observations). This approach of a web-based guide to planktonic ciliates offers a great opportunity for collaboration and expansion to other protists. It could be the basis of a guide to planktonic organisms on a large scale, and we welcome collaboration.
OIL BIODEGRADATION AND MICROBIAL DIVERSITY IN PERMEABLE PAVEMENT STRUCTURES.
Stephen Coupe and Humphrey G Smith. Coventry University, School of Science and the Environment.Permeable Pavement Structures (PPS) have the potential to become powerful in-situ aerobic bioreactors to degrade clean mineral oil. An added oil-degrading microbial mixture was not significantly better at degrading clean mineral oil than the indigenous PPS microflora when provided with an adequate nutrient source. The microbial biomass in a 4-year old PPS rig has shown considerable resilience to abiotic stress and has maintained high oil degrading activity and excellent water quality during this time. Scanning electron microscopy has been used to monitor in-situ biofilm development within lab based PPS and a light microscopy survey of biodiversity has observed microflagellates, naked and testate amoebae, ciliates and metazoa to inhabit PPS systems.
PROTOZOAN PREDATION AS A MECHANISM FOR THE REMOVAL OF CRYPTOSPORIDIUM OOCYSTS FROM WASTEWATERS IN CONSTRUCTED WETLANDS.
Rebecca Stott, Eric May, University of Portsmouth, Portsmouth, E. Matsushita, Université Pierre et Marie Curie, Paris, Elizabeth Ramirez, Universidad Nacional Autonoma de Mexico, Mexico and Alan Warren, Natural History Museum, London.
The removal of the protozoan parasite, Cryptosporidium parvum, from wastewaters is becoming of increasing importance in the UK, especially since contamination of raw waters by sewage effluents has been implicated in major waterborne outbreaks of cryptosporidiosis in recent years. Compared to conventional wastewater-treatment processes, constructed wetlands have demonstrated favourable removal rates for Cryptosporidium oocysts. The removal mechanisms, however, remain unknown. Predation by free-living ciliated protozoa and naked amoebae, which are commonly found in constructed wetlands, was investigated as a possible mechanism for oocyst removal. In laboratory feeding experiments, ciliates (Euplotes patella, Stylonychia mytilus, Paramecium caudatum and an unidentified wetland ciliate species) were exposed to doses ranging from 10 to 106 oocysts/ml for between 5 and 60 minutes. Individual ciliate cells were then removed and their predatory activities assessed by enumerating ingested oocysts (fluorescently labelled with FITC-conjugated mAb) using epifluorescence microscopy. Ingested oocysts were found in all species investigated. Paramecium caudatum demonstrated the highest mean ingestion rates (up to 170 oocysts/hr) followed by Stylonychia mytilus (up to 60 oocysts/hr). Euplotes patella and the wetland ciliate had lower mean grazing rates (4 and 10 oocysts/hr respectively). The amoeba Acanthamoeba culbertsoni was also observed to ingest Cryptosporidium oocysts although the ingestion rate was not determined. The effect of ingestion on oocyst viability is the subject of ongoing investigation. These results indicate that protozoan predation may be an important factor in the removal of Cryptosporidium oocysts from wastewaters in constructed wetlands.
EXCYSTATION OF ZOITES FROM COCCIDIAN OOCYSTS
Conrad King, David Bruce, University College London WCI E.6BT, Jonathan Wastling, University of Glasgow G12 8QQ and David Ojcius, Pasteur Institute, Paris.
Many apicomplexan genera are characterised by the production of spores (oocysts) which are resistant to several chemical and physical agents and are thereby well adapted to survival in the external world. For the parasite life cycle to be completed escape of zoites in the in the host organism is essential. Using video-microscopy excystation was studied in the presence and absence of chemical inhibitors of actomyosin function. The presence of Cytochalasin D failed to inhibit the release of sporozoites from the cysts of Toxoplasma and Cryptosporidium but did inhibit release from Eimeria. However the drug inhibited subsequent zoite gliding motility in all three genera.
PROTOZOA AND GLOBAL WARMING
Wilson D, Montagnes D and Moss B. University of Liverpool.The Ness Climate Change Project is a NERC funded experiment designed looking at how global warming could influence shallow freshwater ecosystems. It combines increased nutrient loading and fish presence with a temperature increase of 3oC in a fully factorised design, looking at how these treatments effect water chemistry, macrophytes, phytoplankton, periphyton, zooplankton and macroinvertebrates. I have concentrated on the microbial foodweb, especially the ciliate community. I will present data from the first year of the experiment which shows that ciliate abundance and biomass is strongly influenced by nutrients and fish but not by the increase in temperature.
PROTOZOAN PARTICIPATION IN BIOFILM DYNAMICS
Jackie Parry, Department of Biological Sciences, Lancaster University, Lancaster, UK.The role of protozoa within biofilms has received very little attention even though their abundance within such surface-associated communties can be greater than that within the surrounding water. This paper summarises the work performed by the research group which aims to characterise the potential impact protozoa exert on bacteria within epilithic biofilms. The paper will include details on protozoan (i) species composition, (ii) seasonality, (iii) grazing rates and (iv) spatial distribution.