A CONTRIBUTION TO DR. GANAPATI'S 80TH BIRTHDAY

Julian RZOSKA

6 Blakesley Avenue, London W5

It gives me real pleasure to write this small contributionfor two reasons; first, I have met Dr. Ganapati on severaloccasions during his cooperation in the InternationalBiological Programma 965-1974, when he was a mem-ber of the International Committee for the Productivityof Freshwater and helped to advise on how to organisethe network of widespread collaboration. He was enthu-siastic and wise both in official meetings and during per-sonal contacts.

Secondly, it was through him, that I was introduced toIndia, its land, people and culture, not to mention itsenormous problems. A country with a great past andan ancient civilisation, colourful, civilised and gentleappealed to me greatly. I pay tribute to Dr. Ganapati andto India.

I have been informed that the celebration of Dr.Ganapati's 8oth birthday will be also the establishment ofthe Indian Society of Limnology. India has a greatnumber of good limnologists-hydrobiologists; I wasgreatly impressed by their work during a meeting on'Aquatic Weeds in South East Asia'; a book containingthe papers delivered at this regional seminar in December1973 was published by Junk at The Hague, Holland, inearly 1976. I admired the discipline of the participants indiscussions and the formulation of summaries and re-commendations. It was one of the best meetings I haveattended as coordinator of the I.B.P.-PF section.

Such high standards and willingness of cooperationspell well for the Limnological Society to be formed onthe 4th of September 1980.

An enormous field of activity opens with such a natio-nal society both looking at the past and at the future. Forthe past the international community of water researchwould be greatly interested, I believe, in a compactvolume of the extent and a survey of results of work in In-dia. The future demands a vigorous pursuit of work onboth 'pure' and applied limnology, so intricately con-nected.

I was recently approached by a publisher to find some-body to write an article on the river Ganges; this approachwas probably dictated by the monograph on the Nile(I976) which I have collated and written; but this was theresult of 12 years of work in the Nile valley. A monographon the holy river, the Ganges, could be the result of aninterdisciplinary team of geologists, sociologists, histo-rians and biologists. A worthy and monumental task forour Indian colleagues! The Nile book and my recentessay 'On the nature of rivers' published by Junk, could bea blue-print for the organisation of such a monograph.

As I am approaching closely the venerable age of Dr.Ganapati, I am given to reflections rather than to activeresearch. This is the privilege of age but also its duty.Young scientists must advance the state of particularfields; after many years of such work older scientistsmust weigh up the general panorama of their and othersfield of results and ideas. This is what I am doing atpresent.

The Bulletin of the British Ecological Society is con-taining an increasing number of articles and letters on thegrowth, complexity and present state of ecology. Goneare the years in which C. S. Elton in his small but classicalbooklet defined ecology as 'natural history'. An enor-mous volume of papers, books and polemics has over-shadowed the above simple term. A whole vocabularyhas been created, often purely mathematical and ela-borate. We try to probe into the functioning of natureor the workings of nature, which to my taste is a reason-able definition of ecology. Concepts like 'energy flow','trophic levels' and these applied to the term 'ecosystem'are current and in my opinion often used like slogans.This last term was invented by the English botanistTansley in 1939 for a patch of vegetation with its abioticsurroundings and associated animals. Such a definition issimple as it stands; it has been made 'precise', denoted asunit of nature bound together by energy flow of its com-ponents.

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Hydrobiologia 72, 3-14 (980). oo0018-8158/80/0721-0013o00.40.© Dr. W. Junk b. v. Publishers, The Hague. Printed in the Netherlands.

As hydrobiologist I have followed the developmentof this branch of ecology with particular interest for 50years. I have worked on lakes in Poland during myyounger years and ended up by working on a long andfamous river. This later work was an eye-opener on somegeneral problems of ecology.

Running waters are treated in research less fully thanlakes and other standing waters; pollution problems

dominate and also the upper turbulent stretches withtheir interesting fauna of insect larvae and greatly adaptedvertebrates. During the ten years of the InternationalBiological Programma about go freshwaters from the

arctic zones to the tropics were investigated as to theirproductivity, only 3 sites were running waters and even

these only partly investigated, all others were lakes. Theflow of caloric energy between the defined trophic levelsof lake eco-systems was the aim of this huge exercise. Thesummarised general account is now in press, published asall other synthesis volumes of I.B.P. by the CambridgeUniversity Press.

I was deeply involved in keeping liaison with the manyresearch teams. Yet it is my belief that although great pro-gress has been achieved in understanding the functioningof lakes, no single waterbody has yielded the complete

coherence of the web of the particular organisms and thephysical and chemical characteristics. Even such 'simple'lakes as the Char lake in the Canadian Arctic with fewparticipating organisms did not achieve the complete cir-cuit of the ecosystem concept. Nature works in a highlycomplex way and especially the consumers, mainly in-vertebrates of the benthos, vary in their food and in itspassing to higher levels. This is a salutory result and doesnot diminish the great value of the whole enormous ef-

fort. In the forthcoming book another set of factors hasbeen recognised as not receiving enough attention, that isthe land surrounding the waterbody and influencing itsproductivity very strongly.

In rivers this is of paramount importance, as rivers

flow through a sequence of landscapes often of differentcharacter. Also the medium, water, flows through dif-

ferent habitats and carries away any metabolic productsof the traversed communities and their environment.

Thus none of the definitions of an 'ecosystem' can beapplied, in other words the concept is not of universalvalue. To give an example, the Nile in its course of 5600km, originates from 2 lakes, Victoria in East Africa andTana in the Ethiopian Highlands, it traverses 3 climaticzones with corresponding vegetation belts, passes througha gorge, rapids, swamps, dry savanna, and finally through

I500 km of desert. Many smaller habitats with differentsets of organisms are passed without influencing eachother in a way demanded by the ecosystem concept.

A long river is quite different from a lake, it 'works' itsway through mountains and plains, transporting waterand sediment for hundreds and even thousands of kilo-

meters. A river can only be understood as a function oftime and space.

I put these reflections to my Indian colleagues if they

should contemplate the highly desirable monographicwork on the great Ganges river.

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