Preface

Abstract

The 2nd conference on 'Algal Modelling: Processes and Management' was held at The University of Reading on Monday July 6th 1998. A full capacity of 50 delegates attended, including visitors from overseas and the U.K. water industry. Twelve papers were delivered in two sessions chaired by Prof. Colin Reynolds (Institute of Freshwater Ecology & Visiting Prof. at the University of Reading) and Professor Paul Whitehead (Director of the Aquatic Environments Research Centre at the University of Reading). A key-note address was given by Prof. Steve Chapra (University of Colorado and University of Reading). Selected papers from the conference have been produced and refereed and now form part of this special issue of Hydrobiologia.

The conference followed the 1st event held in 1996 and published in Hydrobiologia (Howard, 1997a) and aimed to provide an up-to-date review of the state-of-the-art of algal modelling and its application to the management of problem algal blooms. The problem of toxic cyanobacteria provided the basis for the conference and for the papers presented though attention was given to a wide range of hydrological and biological processes. In recent years, there has been widespread media coverage of the cyanobacterial bloom problem prompted by the rapid deaths of many animals after immersion in water containing toxic cyanobacteria and, in 1996, the apparent fatal poisoning of 45 dialysis patients in Brazil after receiving water supplied by a bloom-affected river. Public concern about the potential threat of toxic cyanobacteria is usually justified. The apparent increase in the frequency of problem blooms may reflect increased monitoring, but is also a symptom of the global eutrophication problem. In England and Wales, the organisation responsible for monitoring and protecting the water environment, the National Rivers Authority (now part of the Environment Agency) established a Toxic Algae Task Group in 1989. At the first conference, the group's Secretary, Dr Ferguson, reviewed the extent of the algal bloom problem (Ferguson, 1997) and justified the group's strategy of encouraging the development of modelling solutions for use in management. The original group report (NRA, 1990) states that 'the use of predictive models to quantify the development of algal blooms in relation to changes in environmental variables should be evaluated and further research initiated so that models can be used to devise management plans for different bodies of water'.

Arising from this was the development of the PROTECH (Phytoplankton RespOnse to Environmental Change) series of models (Reynolds Irish, 1997). This volume includes two papers by Elliott et al. that report the further development and validation of the latest version of the model. Findings suggest that the model remains stable when run under a range of different conditions and when applied to the Blelham Tarn enclosure. The workers conclude that PROTECH is a suitable tool for the exploration of community assembly in relation to the ecological themes of competition, succession and biodiversity.

Easthope & Howard present an advanced technique called 'general sensitivity analysis' (GSA) as part of their description of the validation of the model, CLAMM. CLAMM predicts the growth and movement of Microcystis under environmentally variable conditions and makes use of advanced computer technology to provide 3-D visualization. In addition to promising GSA results, the model is applied quite successfully to a lowland reservoir over successive years and this application is a significant development upon the earlier SCUM models which were summarized in Howard (1997b).

Both models appear to have advanced the earlier versions presented at the first conference. There is perhaps a case for combining the advanced computing-based approach and GSA of Easthope & Howard with the vigorously scrutinised science of Elliott et al. to provide a new level of computer simulation in this field. There is also a case for both models to be reprogrammed in a format that will allow them to be accessible to interested researchers via the World Wide Web. A key focus for discussion during the conference was the potential of making models such as SCUM (Howard, et al. 1996) and PROTECH available on the World Wide Web. The view of certain senior delegates from NERC Institute of Freshwater Ecology and the Environment Agency was that there were perceived problems within such organisations that Web-based models may present problems. These problems include issues of computer system security, quality assurance of model output and control over general usage, particularly the inappropriate application of model software. The real problem according to Howard (1997b) is that we are still at a stage where model use generally means reading and analysing published model algorithms and results in academic papers, and maybe devising a new software implementation of the model. Both the new implementation and the original model software are rarely seen let alone used by other researchers and this remains a hindrance in model development. The non-commercial sharing of software via floppy disk or CD-ROM is inconvenient and relies on users having appropriate hardware and operating systems. A model devised in Visual C++ for Windows 95 will be useless to a research unit operating Unix workstations for example. New languages such as Java are, however, platform-independent, run within a Web browser without need for local installation of files and have been designed to protect the user machine from any possible security risk. When accessing a web page that contains an embedded Java 'applet', the code required to run the applet is downloaded from the remote web server and executed by an interpreter built into the web browser. Language design does not allow for any access to be made by the applet to the local file system and when the Web browser is closed no trace of the applet remains on the local system. The development of versions of software systems for use as Java applets on the Web is becoming routine in commerce and in many academic disciplines, but not, at present, in hydrobiology.

Despite the shortcomings in adopting new technology, this volume includes papers that demonstrate real progress in actual scientific modelling. The paper by Frisk et al. is particularly concerned with nutrient dynamics, whilst Krivtsov et al. provide new insights into the phytoplankton of Rostherne Mere. As at the first conference, a key feature has been the inter-disciplinary nature of the research presented with contributions from biologists, engineers, geographers, mathematicians and professional software engineers working in academia and industry. This diverse range of specialists have once again brought new insights to the problems and prospects of “Algal Modelling: Processes and Management”.