AMAZONIANA VI I 47 -6s Kiel, Sept. 1976

The Element Matrix of Amazon Waters and its Relationship

with the Mineral Content of Fishes

( Determinations using Neutron Activation Analysis)

by

Rolf Geisler und Jürgen Schneider

Contents

page

I. Introduction . 4',1

II. Sou¡ce of the mate¡ial analysed .48

IIT. Methods of analysis 5l (a) Principþ of neutron activation analysis 51 (b) Analytical Procedure 52

IV. Results of the qualitative and quantitative water analysis using NAA. 51 v. Mineral content of Amazon fish bones 61

VI. Summary...., 63 Zusammenfæsung 63 Resumo 64

VII. References 64

I. Introduction

It is well known that Amazon water bodies, esp€cially tlrose of the Central region (Fittkau l97l), are extremely poor in electrolytes (Sioli 1950, 1965, 1968; Fittkau 1971, Anonymdus 1972).The limnochemical analyæs for these studies xrere done usirig the cur- rently accepted methods of water analysis e.g. those in the 'German Standard Methods for

47 Water and Waste Water Investigation 197l"(Anonymous 1972). These complexometric and no. Water body Location Date Notes colorimetric methods have limited application at the micro level, and the more sensitive phy- Andes foothills sical metlrods of analysis are therefore particularþ important in tropical limnologSl. As a re- (East Bolivia) n¡lt of collaboration in the hydrogeological tracer experiments in Karst areas of south-west I Rio Beni Puerto Salinas, 25 km Germany (Batsche et al. 1970), the first author became familiar with the technique of neu- west of San Borja, Prov. tron activation analysis (NAA). The possibility of using this method to determine several Beni 13 8.1971 elements, even in extremely electrolyte-poor waters, was tested on ground, drinking,and 9 Rio Manique 4 km from San Borja l5 8.1971 surface waters from the Governmental Seat of Freibtug, a hydrogeologically and geochemi- 10 lgar.apé Chaparina 15 km from San Bqrja 16 Lr97t cally distinct area (Schneider & Geisler 1973). These investigations illustrated the possible Clear water type applicability of NAA in tropical limnology, particularly in recording the element compo- Central region útion ("element matrix") of extremely electrolyte-poor waters; R. Geisler thed extended 11 Rio Tarumã Near Manaus, bridge on the use of NAA to cover a limnological-ichthyological investigation carried out between road BR 174 4. 9.I9'll August and Decembet l97I in Brazilian and Bolivian areas of the Amazon: l2 Rio Tarumãsinho l0 kmabove mouth 3.f1.1971 l3 Curuçambá ca. 9 km north of ôbidos?.10.1971 t4 Rio Curuá Proposed road between ôbidos and Alenquer 9.10.1971 II. Source of the material analysed l5 Rio Tapajóz Lowet course, near Bel- tgÍa 22.1I.1971 The purpose of the investigation was to produce a survey of the element matrices of 16 þarapé Jacundá ca.25 kmabové San- Luxurious growths all water types found in the Amazon (see Sioli 1965), including the Central region, the bio- tarém, right bank of Rio ofaquatic plants (Ca- logically productive northern and southern border areæ (see Fittkau l97l),and the Andes 'rtpaj6z 23.1I.1971 bomba, Nymphaea) foothills. The geographical location of the sampling stations is shown in Fig. 1. Since ttre l7 Lago Calado*-Igarapé Near Manacapurú, north geochemical structure of an area can result in the occurence of various water types within do Pato mouth bank of the Rio 28.10.1971 even a relatively small area, it is necessary to provide additional information about the sam- Southern border area Solimões pling sites (Table 1). @ondonia) 18 Rio Machado Above the city ofRondonia .

Table 1 : Geographical characterisation of the water samples analysed by neutron activation 17. 9.t971 analysis. 19 Rio São Marco 87 km south east of 19. 9.1971 Porto Velho, bridge Sample no. Water body Location Date Notes on road BR 364 \{trite water type Northern border area (Roraima) Central region 20 Rio Xeriuní Lower course,20 km 19.10.1971 I Rio Solimões Manacapurú, mid-rive¡ 10.1f .1971 above mouth 2 Amazonas Óbidos,mid-stream 25.ll.lg7L 2l As above Middle course, at the 6.12.1971 3 Rio Madeira ca. 10 km above mouth 16.11.1971 geographical level of 4 Rio Pu¡ús lower-rJÐuÍre,.neu 9.lI.l97L Biotop of Sym- Boiacu Berl¡ri 9.Il.l97l physodon aequi- 22 São Angelo mouth in Rio Xeriunl 20.I0.197L Biotope of Cheirodon fasciata (Pisces, þarapé near sample 20 axelrodi (Pisces, Cha- Cichlidae) racidae) Southern border area (Rondonia) 23 Igarad Curubaú ca. 20 km above the Rio Biotope of Symphy- Branco mouth,left bank 1 8. 10. 1 9? 1 sodon discus 5 Rio Madeira Porto Velho, midl¡iver 19. 9.197L Northern border area 24 Rio Miang northernmost part of 8.12.1971 (Roraima) Roraima, near Surumú lgarapé Daeora Near 9.L2.1971 6 Rio Branæ Boa Vista tt.t2.t97t 25 Surumlr 26 Rio Pa¡imé Carries road BR 9.t2.1971 7 Rio Murupú no¡th of Boa Vista, 174 road crossing BR 174 8.L2.1971 *Mixed wate¡: white wate¡ (from the Solimões) and clear waler (inflows from the terra firme).

48 49 no. rilabr body Datp Notes Andes foothills (East Bolivia) 27 Lago Palá 18 km from Reyes, 12. 8.1971 hovince Beni 28 Iqgo Copaiba as for no. 27 t2. 8.1971 29 kgo la Granja 25 kmwestofReyes, 13. 8.1971 river a¡ea of Beni Black water type 30 Mid-riner, before the 22.t0.1971 mouth of the Rio Cuieiras

The lowlands of eastern Bolivi¿ v/ere travelled in August 1971 ï¡ith Professor Gæton Bejarano of I¿ Paz. Due to unforseen potitical circumstances, work in the eastern Andean slopes ('tungas") and in eastern Bolivia, still limnologically and ichthyologically uncharac- terised, had to be prematurely discontinued. Mr. Glück (Manaus) was a reliable interþreter and tireless helper for the local sampling programme in the Brazilian Territorio Rondonia. Thanks are due to the board of the Wissen- schaftliche Geællschaft, Freiburg, for financial support for the joumey into this southern border area of the Amazon. The results of the water and faunal analyses from eastern Bo- livia and Rondonia will be published separately. In the CÆntral Amazon !\,e nrere given much help and hospitality by the patres Fran- ciscanos in Obidos and Alenquer; speciâl thanl$ to Father Richard Havertz OFM and Fa- tþçr-Marius Ltike OFü The investigations in Territorio Roraima were carried out together with our colleagues from Plön, Dr. F. Reiss and Dr. U. Irmler.

III. Methods of analysis

A large number of elements had to be determined, some qualitativeþ and some quan- titativeþ, in this investigation of Amazon waters and fìsh bones. The concentrations encorm- tereC rtrnged from some milligrams per litre to trace concentrations of some micrograms per litre and less. Since it was a long and complicated prooess to transport the samples from the sampling station to the place of analysis, quantities had to be limiied to one litre of u¡ater and a few grams of fìsh bones, and the analytical procedure had to be one which permitted the simultaneous determination of several elements (socalled multi+lement methods). Neutron activation analysis fulfilled these requirements very well. Tlrc principle of this type of analysis, its advantages, and the practical considerations related to water analysis have already been fully discussed by J. Schmitz, J. Schneider & H. Vogg (1972) so little ¿õtait is necessary here. Points particularþ relevant to the Amazon samples are discussed below. (a) Principle of activation analysis

In activation analysis, the inactive atomic nuclei of an element A are bombarded with . projectile particles x, which can be neutrons, protons, deuterons, c-¡nrticles, Tquanta or any ofvarious other particles B. lVhether such a nuclear reaction can be used foithis type

51 of analysis immadiately a Ge (Li) Detector and a 4000 channel analyser. The other samp' depends on the fulfilment of certain basic requirements. The probability of a measured with allow time the very high Na and Br activities missile particle X meeting and reacting wilh an atom A must be large (the measure of this les could only be measured after 7 days to for after a month. A is shown graphically in probability is called the operational cros-section);it must be possible to produce a projec- to decreæe. They were measured again 7-spectrum tile particle beam of great density; and the radioactivity of the resulting particles S i.e. the Fig.2. peak areas was done using a Telefunken TR 86 cal' radiation emitted during decay mus! be easily measurable. Except in a few cases, these re- The quantitative evaluation ofthe quirements are fulfilled best by reactor irradiation with thermal neutrons. This absorption of culator coupled to the multi-channel analyser. pre-treatment required. The bones were neutrons results in the formation of mostly unstable isotopes; these, in the emission of p- For the fìsh bone analyses, no special was caught, and the inadiation and measuring particles with accompanying 7-radiation, decay with a half-life characteristic for every radio- removed and dried immediately after the fish were the water samples. nuclide, exact measurement of 7-energy permits qualitative identification of the elements in the re- procedures were analogous to those used for sulting sample. Since the intensity of the 7-energy is proportional of the amount of element present, a quantitative analysis is possible provided the amount of irradiation and. the measuring parameters precisely are known, or if a known amount of a standard sample is processed under lñDll.. identical conditions. With these analyses, the second (i.e. the socalled standard method) was used. "o-p"r"bl. (b) Analyticalprocedure ¡ Í Sample treatment is extremely important in water analysis. Glass containers could not r0 000 t be used for the samples, not only because thêy are too fragile and heavy but because ¡ ¡ alkalis ¡ g t are released from the glass and certain elements (especially the trivalent ones) are adsorbed ¡ ! t¡ on to it. For this reason, polyetþlene bottles were used, except traces of Ti and Al (which are t ù ? t 2 ¡ ¡ t ¡ 3. å ¡ catalysts necessary for polymerisation), metallic components a-re absent. However, tìtte is ¡ ¡ '¡ ; l:5 Irl t: 3 I' ¡ known at present I .t g ¡ about their adsorption ch¿racteristics, especially with regard to trace ele. 4.3 rÊ; ¡ t. .t {t a I ; ¡ F! I ments. Using radioactive tracer techniques it was established that there wai no adsorption of I Í i i. Zn and Co on to these bottles over a period of several months. The bottles were carelufly pre'treated four times at weekly intervals with heated, double quartz-distilled water. The Én.rgt [foV] problem of drying the samples was thoroughly investigated. Beõause of the high levels of 7'radiolysis in the reactor, only the dry residue and not the sample itself can be inadiated. As with sample transport, the loss of some elements and contamination with othen from external sources must be avoided during the drying process. This is impossible nôt only Fig. 2: Sample from Rio Murupû, Roraima, Brazil (see Table l, No. 7). inadiation with conventional drying, but also with surface evaporation since vohlile compounds (e.g. 3day activation with reactor neutrons, T-spectrum 7 days after alþl halides, Hg, As, sb, se and others) are partially lost by evaporation, and interactions with the container material þlatinum or quartz) cannot be avoiáed. Freezedrying, in which water the is removed by sublimation from the pre-frozen samples, proved to be the best technique. Another advantage of this technique, which is extremely important for the Amazon water samples, is that the dry residue had a spongy consistency and could easily into the inadiation and weighing containers. Since the samples yieldeda very small amðunt of dry residue (15 mgf for the Rio são Marco sample as against 300ó00 mgfl from the Rhine)j the loss of only a few milligrams from the drying container would ha-ve led to a relativeÇ large analytical error. To enable identification of the 22 specified elements (see Table 2) the samples had to irradiated be for a short period (5 minutes) for those radionuclides with half-lives in the region of minutes and hou¡s (Mg, Mn and Na), and a longer period (3 days) for the other radionuclides, which have longer half-lives. The irradiatioi was carriàd out in an FR 2 reactor at Karlsruhe, with a neutron flux of 8 and 9 x l0l3 neutrons/cm2sec respectively. For the quantitåtive analyses of Ca, Mg, Ba, Na, Mn and Fe, standard samples were irradiated si- multaneously. The radioactivity of the samples exposed to short period irradiation r ¿s

<,) 53 Table 2: Element fnatrix of Amazon water bodies. no. Water An Ba Br Ca Ce (t C, Cs Fe IIf I¿ À{g Mn Na F¿ Rb Sb Sc Sm yb ZÃ Central region 1 Rio Solimões + ++++++++++++ +++++ +++ + 2 Amzzonas + ++++++ ++++++ +++++ +++ + 3. Rio Madei¡a ++++++++++++ + + + + + + + + + 4 Rio Purús + + +. + + + + + + + + + + + + + + Southe¡nbordera¡ea (Rondonia) + + + 5 Rio l[adeira +++++++++++++ + + + + + + + + + Northernborderarea (Ro¡aima) ++++++++++++ + + + + + + + + + 6 Rio Branco ++++++++++++ ' + + + + + + + + + 1 Rio Murupú +++++++++++2 + + + + + + Andes foothills (East Bolivia) 8 Rio Beni + ++++++++++++ ut +++++ +++ + È 9 Rio Manique +++++++++ +++ +++++ +++ + 10 þarapé, Chaparina +++++++++++++++++++ Clear water type Centralægion 11 Rio Ta¡umã ++++++++++++++++++++ 12 Rio Tarumóinho ++++++++++++++++++++ 13 Rio Cwucambá +++++++++++.++++++++ 14 Rio Cuuá +. + + + + + + + + + + .+ + + + + + + + + 15 Rio Tapajóz +++++++++ + + + + + + + + 16 þarapé Jacundá ++++++++ +++++ ++++ + L7 l¿go C¡tado-Ig. Pato +++++++++ +++++ + + + + Southe¡n border area @ondonia) 18 Rio Machado +++++++++. + + + +. +. + + + + + + + 19 Rio SiÍo Ma¡co +++ +++++ ++++++++++ + + Nortlrern bo¡der açq __1$q¡4!rn4l m Rio Xeriunf +++ ++ + + + + + ++ ++++ + + 2L Rio Xeriunf ++++ + + + + + + + ++ + + + + + + 22 þarape São Argelo + + + + + + + + + + ++ + + + + +

no. Water AnBaBrCaCeCoGCsFe Hf HS La il[g Mn Na Pa Rb Sb Sc Sm yb Z,¡l area 23 Iga¡ape Curubaú + +.+ + + + + + + ++++++++++ 24 Rio Mialg ++++++++++ ++++++++++ 2t Iganpé Daæra ++++++++++ +++++++++++ 26 Rio Pa¡imé +++++++++ +++++++++++ Ardes foothills (East Bolivia) 27 IagoPalÅ +++++++++++++++++ 28 Lago Copaiba ++++++++++ ++ ++++ ++++ + 29 Iago Ia G¡anJa +++++++++++++++++++ Black wãîer type 30 Rio Negro +++++++++ + +++++++++

+ = q¡alitative detected ? = limit of detection no sþ = not detect¿ble

(,rtt lable 3:Quantitative NAA anal¡nes

no. lYater C¿ Ba Na Mn Fe cl water type TEII tÆ,ll Ælr pelr Ælr tßlr Ælr @ntralregion I Rio Solimões 300 6 800 50 I 400 58 I 3s0 800 2 Amazonas 2 800 160 37 1 100 1s 2 300 3 Rio l{adeira 3 000 2 100 115 2100 35 3 400 4 Rio Purf¡s 2 t00 r 700 60 I 300 23 3 800 500 Soutlprn bo¡der area (Rondonira) 5 Rio Madeira 8 300 I 300 36 I 500 29 750 Northern border a¡ea (Roraim¿) 6 Rio Branco 660 30q 20 1 1s0 8 300 7 Rio Murupú 440 fLd. 6 1 250 5 60 no. Water body Ca Ba Na Mn Fe cl water type pslr Æll Ælr Ælr Andes foothills (East Bolivia) 8 Rio Beni 10 600 2 200 t20 3 500 30 1 700 9 Rio Manique 13 300 3 800 160 2700 7 4 500 10 þarapé Chaparina 7 900 I 600 83 17 000 59 2 t00 Clear wáter type Central region

1t Rio Ta¡umã n.d. 280 5 860 2 70 t2 Rio Tarumlisinho ? 105 2 t25 2 40 13 Rio Curuçambá 740 34 7 s60 3 90 L4 Rio Curuá 680 400 t3 I 4s0 7 490 l5 Rio Tapajóz 780 $a 18 3s0 1t 3s n0 16 Jacundá þarapé r 800 190 l4 830 I 20 t7 Lago Calado - Ig.Pato 2 500 ?Jì 510 l3 670 2 40 o\ Southern border a¡ea (Rondonia) l8 Rio Mach¿do I 000 2 too l5 3s0 I 2t0 l9 Rio Säo Marco rLd. 60 10 150 4 180 Northern border area (Roraima) 20 Rio Xeriunf rLd. n.d. 2 200 18 190 2l Pio Xeriunf 630 nd. 5 200 2 490 22 þarapé São Angelo nd. ttd" -nd" 9 230 2 95 300 23 Igarapé Curubaú 200 l8 360 11 290 100 u Rio Miang 256 30 I 100 4 130 25 þarapé Daeora 380 t20 8 2 500 3 60 26 Rio Parimé 580 960 44 2700 13 60 Andes foothills @ast Bolivia) 27 I-ago PalÁ, I 200 2 100 L2 r 900 7 300 28 Lago Copaiba I 500 700 n.d. r 800 2L 400 29 I-ago La Granja 23 200 2200 55 2 s00 70 100 Black water type 30 Rio Negro 460 n-d. l0 550 6 310 ? = limit of detection rl"d. = not detectable

iå r Ë'= Ë åå 3 r +eq Fg î 3 gÞF* PË * q i*iã;q s "¿ q F a F H,ssååF+ Ë Þ É.qq#TBEFHËãå ? Ë

Þ ¡**s1F€q5Ër€ Ë r ô g Þ) å (,r sn**åiåäËåäå \ì Þ ä*AäÈË9sff93ä ä Ê (D

(tEt z så$gååsl Þ ËåååååäËëååËEïö *EägåË€ cå F ä õ{eEE'Ía8 á Z sååå å+äå=å[ãåËêt åår*e s/-ËEäåäÃu : e Ë g il-,'E ã'Þ ø äååå;Ë$3ggSgg$iåEgËå gË F ,\

Fig.3 : Geochemical distribution of Ca.

(- I \oo

I t t ,

\.,

\ I

Fig.4 : Geochemical distribution of Mg. o Analysis positive o Analysis negative

58 Barium distribution is shown on a map, since the bones of fishes from a water body Clear water. extremely poor in Ca (no. 23\had' an increased Ba content; this leads to the speculation From the "Central region" analyses have been done on the 'tlassic" clear water river that perhaps the alkaline earths needed for bone formation (Ca and Mg) can ..substituted', bi Tapajoz, which obtains its characteristics from the Central Brazilian Shield, and from the by Ba (see page 62 ). rivers Curuçamba and Curuá which ariSe in the Precambrian rocks of the Guayana Shield. The fact that the element matrices of all the water types examined are simila¡ (excluding The element composition of these water bodies was almost identical, i.e. Ca 0,7-0,8 mg/l the stated important exceptions) naturally reveals nothing about the biological availÀility (see Table 3). In four of the clear water samples (nos. 1 I and 12: Rio Tarumã near Manaus, of the elements since NAA techniques do not show the nãture of the physical or chemicai bonding. no.22 from the river area of the Xeriuni, and no. 19: Rio São Marco near Rondonia) Ca could not be detected using NAA. In spite of the mineral defìciency indicated'by this fact Groth (1971) in his studies of the biotic and abiotic factors vitally important pro- to there is a 'lnormal" fish fauna in the upper reaches of the Rio Tarumã and in the streams duction biology, examined in detail the trace elements Mn, Fe, co, cu, zn anúMo in north German lakes, São Marco and São Angelo. Fittkau (1973) mentioned the allochthonous nutritional basis and concluded that in none of them was there atraceelement deficiency. The qualitative'results of the fish fauna in such streams. of the NAA showed that this was also the case in the Amazon water bodies investþted, The results from the clear water rivers in the middle and north of Roraima i.e. from and the complete array of trace elements was detected in all water types. The the Guayana Shield, resemble those of comparable water bodies of the Central Brazilian element matrices of white, clear and black waten were not sþificantly different. i{o*rurr, the water Shield. A more detailed treatment of the limnochemistry of some running waters of Roraima type does affect the biological availability of the elãments; the high humus and is in preparation. levels of black water and the large amounts of suspended clay minerals in white water It must be repeated with regard to the Andes foothills that the planned sampling pro. influence decisively the mobility of nutrients by complex formation and ion adsorption. gamme could not be carried Òut here, and it was impossible to sample the clear water rivers. This was demonstrated experimentally by the culture experiments of Sclrliihting (196g). Nos. 27 and 29 (Table l) are lakes which have no connection with running water during the It is therefore extremely important that the organic or inorganic components which in- dry period; whether such a connection existed in the rainy season could not be ascertained fluence or even block nutrient uptake in tropical white and black watãrs be identifìed. due to travel difficulties in this undeveloped area. These lakes have transpariencies of 1,8 m Table 3 shows the results of the quantitative NAA. It is convenient to discuss these (Lago Palá) and 2,8 m (Lago La Granja) and can therefore be in relation to the different waler types: only compared to a certirin White water. extent with true clear water rivers. The lakes of the Andes foothills have a relatively young ,,central and not yet extensively leached. The levels of the alkaline earths in the waters of the region,' i.e.2_6 mg/l ca and 0,2'1,7 mgr Mg pe Black water fall within the known range. The very high level (1,4-3,g mg/tJ is a result Only one black water sample, from the lower course of the Rio Negro above Manaus, of the high seston content of the white water, the impo-rtance of which for the trans- cotrld be analysed.by NAA. Comparison of the analysis results of this single sample with port of trace elements was discussed by Gibbs (1973). (Anonymous are those of the long-term chemical analyses of H. Ungemach 1972) shows that Fþres now available from the Bolivian part of the Andes foothills. Aerial obser- r¡ations there is extensive agreement. showed that the Amazon tributaries arising in the High Andes fìrst exhibit the presence of a seston load in the last but one pre-mountain chain. It *itt ¡r shown later by R. Geìsler in more detail that the high seston load suddenly appears very strikingly on a stretch ofriver Mineral content of Amazon fish bones report) only V. þreliminary a few km long. our white water samples from the area around Reyes ano san Bo{a @rovince Beni) were 3545 km in a straight line from this pre.mountain zone. The white The low levels of alkaline eartln in clear and black waters, confìrmed by water extremely rivers sampled were deep red-brown in colour and in August (dry season) the trans- the results of the NAA (see page 56 ), led naturally to examination of the mineral compo- parency (Secchi disc) was only 4'6 cm (!). In comparison, the value foi white water rivers sition of the fìsh fauna inhabiting the different water types. of the Central Amazon is 25-30 cm. High levels of alkaline earths were also found here in The feasibility of establishing a relationship between fish physiology and water type eastern Bolivia, i.e. 8-13 mgfl Ca and !,6-2,2 mgf Mg. eæly on appeared greater ifthe analyses were conducted on fìsh ofone species (or belonging White waters sampled in the northem border area (Roraima) included the Rio Branco at leæt to a species-poor ) which are restricted to one particular water type. The genus and its main inflow, the Rio Murupu. The seston and therefore the mineral content was Symphysodon (Cichlidae) was thought to be suitable; as far as is known at present, S. disc¿s considerably lower than in white water rivers of the Central region. The limnochemistrf and Heckel is restricted to clear water and S. aequifosciata ecotyp (?) "Royal Bltre" is found ecology of the Rio Branco ("White River,') as well as observati,ons from a trip there in ño- only in white water (Geisler 1972\. Therefore the mineral composition of vertebral columns vember 1967, show that it is no fully comparable with the Rio Solimões-Amazonas. The of discus fishes from clear water @io Curubafi, sampling station no. 23) and white water water bodies 6 and 7 are classified as white water on purely optical grounds, but the levels (Paraná de Beruri - Rio Purus, sampling station no. 4) were examined quantitatively using of Ca, Mg, Fe and Mn are similar to those for clear *ut", ,ir""*, oflhe Central Amazon. This NAA. indicates anew the problems arising when river types are given generalised designations.

60 6l These early results allow no greatly detailed interpretation, but they do indicate clearly the re- Materials and methods. lationship between the mineral content of Amazon fish vertebrae and the particular limnochemical features of the water type in which the fish occru. A more detailed quantitative investigation of such could provide the foundation for a feature It first had to be established whether the mineral levels along the vertebral column were uniform relationships more intensive exploitation of the fish of Amazon waters, or as would be expected, differentially distributed according to the observed mechanical st¡esses on the In conclusion, a critical evaluation of the use of NAA in tropical limnology is in o¡der, verteb¡ae. Since only a few specimens of Symphysodon we¡e available for investigation, preliminary ana- NAA,is of most use in the analysis of metallic trace elements and in drawing up element matrices. lyses were done on the ve¡tebral columns of Prochilodus insignis ("Ianø"). The columns of 11 specimens is only through the use of such multi+lement methods previously (obtained from Lago Castanho south-west of Manaus, see Menezes dos Santos 1973) were divided into It that elements thought to be absent c¿n be detected. four parts of oqual length and the ash content of each section determined. The results are shown below: Analysis of levels of alkaline earths, extremely important not only in the Amazon but in all wate¡ bodies of the humid tropics, is possible with a greater degree of sensitivity using NAA than ryifJl the com- Table 4: Ash content (as a percentage of the dry weight) of the vertebral columns of hochi- plexometric EDTA method. In addition, Mg can be determined di¡ectly instead of by difference. lodus insignis (from cranial to caudal). It wæ unnecessary to subject the bone samples to complicated dissolution procedures, thereby avoiding yield and blank determinations. 17,0% 23,2Vo 23,6Vo L7,9% The disadvantages of NAA, apart from the cost of analysis, a¡e the difficult access to a nuclear reactor and the considerable amount of time required both for the actual analysis and for the evaluation The vertebrae of the third section (= tail vertebrae beginning after the body cavity) were used for of the ¡esults in a computer centre. the mineral composition analyses. In addition, it had to be determined whether size or age affect the total mineral content (ash content) of a fish species. The ¡esults were as follows: VI. Summary Table 5: Mineral content of the tail vertebrae of hochitodus insignis (obtained from Lago Calado, December l97l) Thirty water samples from different water types of the Central Amazon, the southern (Rondonia) and no¡thern (Roraima) border areas, and the Andes foothills (Bolivia, Province Beni) were analysed .Standard length Ca Ba Cs Mg Na using the technique of neuüon activation analysis. Qualitative analyses were ca¡¡ied out for the following Vo ppm ppb ppm ppm 22 elements and trace elements (Iable 2): Au, Ba, Br,-Ca, Ce, Co, Cr, Cs, Fe, Hf, Hg, La, Mg, Mn, Na, Pa, Rb, Sb, Sc, Sm, Yb and Zn. Of these, Ca, Mg, Ba, Na, Fe, and Mn (Table 3) were determined quan- L2,O 14,0 35 20 2600 2000 titatively. t3,2 16,0 10 s0 2400 2000 The qualitative analysis gave a surprisingly uniform picture in that 14 of the elements wete present r7,s 16,2 l0 30 2s00 1700 in all the water bodies sampled. Those not present in all waters we¡e Au, Hf, Hg, Pa, Rb, Yb and, of par- 25,0 15,1 30 60 2000 1700 ticular importance in production biology and nutritional physiology, Ca and Mg, The quantitative analysis showed that the levels of the elements investigated dec¡eased f¡om the border areas and Andes foothills in the direction of the Central region; however, exc€pt for Ca and Mg, It is clea¡ that the total mineral content (and especially, level of Ca) does not depend on the size no elements are actually missing. of the fish and the small differènces obtained could be disregarded. The fact that Ca and Mg could not be detected at the sensitivity level of NAA in some water bodies Unfortunately it was impossible to analyse a sufficient number of ,Sym physodon vertebral columns which nevertheless had rich fish populations, prompted investþations into a postulated metabolic-phy- from diffe¡ent water types to enable statistical analysis of the results. More than 20 columns of Symphy- siological relationship between fish and wâter type. The fish genus investigated was Symphyødon (Cich- sodon were prepared for analysis on the spot immediately afte¡ the fish had been caught; however tle lidae): S. d¡scus inhabits clear waters and S. aequífasci¿l¿ inhabits white waters. The mineral content of high temperatu¡es and humidity occuring during transport caused many of the samples to become mil- the vertebrae of these two fish species differs clearly according to the limnochemistry of their respective dewed and unsuitable for analysis. Only foúr respectively five vertebral columns were in good enough habitats (Table 6). condition for NAA in the Nuclear Research Centre at Karlsruhe.

Table 6: Mineral content of tail vertebrae of Symphysodon,fromdifferent water types of the Amazon. Zusammenfæsung

Ca Ba Cs MC Na In 30 Wæserproben verschiedener Gewässe¡typen aus Ze¡tralamazo¡ien, dem südlichen (Rondonia) % ppm ppb ppm ppm und nö¡dlichen Randgebiet (Roraima) sowie aus dem Andenvorland (Bolivien, Provinz Beni) wurden 22 Elemente einschließlich Spurenelemente qualitativ (Au, Ba, Br, Ca, Ce, Co, Cr, Cs, Fe, Hf, Hg, La, Mg, Mn, From "clear water" (n=4) 6,8 370 50 4300 2900 Na" Pa, Rb, Sb, Sc, Sm, Yb und Zn) mit de¡ Neut¡onenaktivierungsanalyse bestimmt (Tab. 3). From "white water(n=S) 13,4 B0 40 3000 1400 Bei den qualitativen Befunden rvar dris Bild übe¡ræchend einheitlich: 14 der 22 Elemente konnten in allen Gewässern nachgewiesen werden mit Ausnahme von Au, Hf, Hg, Pa, Rb, Yb sowie - produktions- The above lesults must be verified by analyses of more samples; however, there seems to be a re- biologisch und ernährungsphysiologisch von besonderer Bedeutung - von Ca und Mg lationship between the mineral content of the fish bones and the water type since verteb¡ae offish from Die tiuantitativen Untersuchungpn zeigten zwar eine Abnahme in der Elementmenge von den Rand- white wate¡ ¡ich in minerals have a mucþ hþher Ca content than those of fish from clea¡ water. The lo'iv gebieten und dem Andenvorland in Richtung des zent¡alen Raumes, jedoch kann in keinem Fall - mit Ca level in the "clea¡ water" Symphysodon was partiatly compensated for by a higher level of Mg, antt the Ba content was also considerably higher.

63 62 gewisser RöNICKE (L21Ð: Isotopenverdünnungsanalyse.- Chem. Ing Ausnahme von Ca und Mg - von einem extremen Mangel an Spuænelementen gesprochen we¡den, KLOCKOW, D., H. DENZINGER u. G. Das Fehlen.eines Nachweises für Ca und Mg (im Rahmen der Empfindlichkeit del ÑAA) in einigen Techn. 46, 831 Gewässe¡n (19?3): über Wæse¡bewegungen, chemische Schichtung und Fisch- mit reichem Fischbestand führte dazu, nach stoffwechselphysiologschen Beziehungen zwischen MENEZES Santos, de Beobachtungen Fisch Solimões (Amazonas),- Oecologia 13: 23*?A6 und Gewässer zu suchen. Als Objekt gewählt r4rurde die Gattung Symphysodon (Cichlidãe): S. d¡scas wandenrngen in Var¿eaSeen am mittleren Bewohner (t97L): Calcium and Algal Cell ist des Klarwassertyps, während,S. aequífosciøta im Weißwassertyp angetroffen wird. Im Mineral- MOSS, S.W., J.P. THOMAS and J.C. O'KELLY Strontium-substition for bestand von Wirbelknochen dieser Fische scheint in Korrelation zum limnochemìschen Milieu eine deut- Size.- Physiol. Plant. 25: 18+187 liche Differenzierung (Tab. 6) gegeben. SCHLICHTING, B, (1968): Die Beeinflussung der Nährstoff-Aufnahme durch Huminstoffe.- Mitt. Deutsch, Bodenkundl. Gesellsch. 8: 165-167 SCHMITZ, J., J. SCHNEIDER u. H. VOGG (I972'l: P¡aktische Erfahrungen mit der Neutronenakti- vierungsanalyse v on Wissern.- GWF-Wasser/Abwasser I 13 : 3 I Ù3 24 Resumo SCHNEIDER, J. u. R. GEISLER (1973): Spurenelementbestimmungen inverschiedenen nattiilichen Wasserproben mittels Neutronenaktivierungsanalyse.- Z, Ãnal. Chem, 267: 270'273 Em 30 amostras de diferentes tipos d'água da Amazônia Central, da região marginal sul (Rondônia) SIOLI, H. (1950): Das Wasse¡ im Amazonasgebiet,- Forsch. u. Fo¡tschr. 26t 274-280 e norte (Roraima), assim como da região pr6andina (Bolfvia, Provfncia Beni) foram deierminados qualitati- SIOLI, H. (1965): Bemerkungen zur Typologie amazonische¡ Flüsse.- Amazoniana I: 74-83 vamente 22 elementos inclusive oligoelementos (Au, Ba, Br, ca, ce, co, cr, cs, Fe, Hf, Hg La, Mg, Mn, SIOLI, H. (1968): Hydrochemistry and Geology in the Brazilian Amazon Region.- Amazoniana 1: Na, Pa, Rb, Sc, Sm, Yb e Zn) por meio da análise de ativação de neutrons (Tab. 2), dos quais qu"ititutiuu- 267-277 mente Ca, Mg, Ba, Na, Fe e Mn (Tab. 3). Os achados qualitâtivos forneceram uma imagem surpreendentemente uniforme: 14 d,os 22elementos puderam ser-comprovados em todos corpos pa, os d'âgua com exceção de Au, Hf, Hg, Rb, yb, assim como Accepted for publication in February I 975 - de importâ-ncia especial ponto do de vista da produtividade Uiotôgica e Oa iisioiágia nutricional - Ca e Mg. quantitativas - As análises mostram um decréscimo da quantiãde de elementàs das regiões marginais- préandina e em direção da área central, porém não se pode falar em nenhum caso - com certa exceção de Author's add¡esses: Ca e Mg - de uma falta extrema de oligoelementos, falta de comprovação palaCa (dentro -A e Mg dos limites de sensibilidade da AAN) em aþns cor- Dr. Rolf Geisler Dr. Jürgen Schneider pos d'ágtra-com rico povoamento de peixes levou à procura de relações metabõlicofisiolôgicas en-tre peixe Regienrngspräsidium Gesellschaft für Kernf orschung e iorpo d'água' Como objeto foi escolhido o gènerõ symphysodoi lCicttlidae): S. discus1habitante do - Fischereireferat - Laboratorium ñir Isotopentechnik de tipo água clara, enquanto.S. aequifasciata é encontrado no tipo de água bránca, No teor de mine¡ais 7800 Freiburg 7500 Karlsruhe 1 das vértebras patece ser dada uma correlação com o meio limnoqufmicð. BR Deutschland BR Deutschland (Tradução por Dr, Reimar Schaden),

VII. References

ANONYMUS (1972): Die Ionenf¡acht des Rio Negro, Staat Amazonas, Brasilien nach Untersuchungen von Dr. Harald Ungemach. - Amazoniana III: l ? 5-1 85 BATSCHE' H. (1 970): Kombinierte Ka¡stwasseruntersuchungen im Gebiet der Donauversickerung (Ba- der¡\{ürttemberg) in den Jahren 1967-1969 Stei¡. Beitr. Hydrogeol., Jahresband G¡az 1970 BERG' A.(1972): Studies ôn the metabolism of Calcium and St¡ontium in freshwate¡ Fish, part IV. - Mem. Ist, Ital. Id¡obiol. 29: 145-167 (1967): BUCHTELA, K. Aktivierungsanalytischer Nachweis von Markierungsstoffen zu¡ Verfolgung unterirdischer Wässer. - Steirische Beitr. zur Hydrogeologie 1g/19: g7-9g. FITTKAU, E'J. (1971): ökologische Gliederung des Amazonasgebietes auf geochemischer Grundlage. - Münster Fonch. Geol. Palâont. 2Ol2l:35-50 FITTKAU' E,J. (1974): Zur ökologischen Gliedenrng Amazoniens. I. Die erdgeschichtliche Entwicklung Amazoniens. - Amazoniana Y:77-134 FöRSTNER, U. und G. MÜLLER (19?3): Heavy metal accumulation in River sediments. - Geoforum 14:53-61 FöRSrNER, u. und G. MÜLLER (L974): schwermetalle in Flüssen und seen.- springer verlag GEISLER, R. (f 9?2): Blaue und braune Discus in Amazonien Echter Discus im Flußgebiet des Rio Negro. - Tats. und Inform. a"d. Aquaristik 6 : l3-15 v ZIZZ GEISLER, R., H.A. KNöPPEL und H. SIOLI (197I): ökologie de¡ Süßwasserfische Amazoniens - Stand und Zukunftsaufgaben der Forschung. - Naturwissenschaften 5g: 303-31 I GIBBS,R,J. (1973): Mechanism of rraceMet¿lrransportinRiversscience rg0 71,-73 GROTH' P' (197f): Untersuchungen über einige Spurenelemente in Seen. - Arch. Hydrobiol. 68: 30$325

64 65