A comparative limnological study of the Guadalhorce reservoirs system (Málaga, S.E. Spain)

ARTICLE SCIENTIA ge undensis, 16/2:27-41 (1990) A COMPARATIVE LIMNOLOGICAL STUDY OF THE GUADALHORCE RESERVOIRS SYSTEM (MALAGA, S.E. SPAIN) J. A mengoll, J. Ca alánl, N. Gabellone2, D. Jaumel, J. de Manuell, E. Ma il, J.A. Mo guil, J. Nollal, J. Peñuelasl, M. Real', J.L. Rie al, S. Saba e l, F. Saba e l, & J. Toja2. 1. Depa amen &Ecologia, Facul a de Biologia. Uni e si a de Ba celona. A inguda Diagonal, 645.08028 Ba celona. 2. Depa amen o de Ecologia, Facul ad de Biologia. Uni e sidad de Se illa. Apa ado 1095. 41080 Se illa. RESUM A pa i de les dades ob ingudes en les isi es du an el pe íode de ba eja (ma $ 1988) i es a i icació (se emb e 1988) en els es embassamen s del Sis ema Guadalho ce, s'anali - zen les espec i es di e kncies ísico-químiques i biolbgiques. To i que els es embassamen s p esen en un con ingu en sals dissol es ela i amen al , Conde de Guadalho ce és d'aigües ca bona ades, men e que a Guadalho ce són impo - an s els clo u s i Guadal eba é composició in e m dia. En aques s dos da e s embassa- men s la p eskncia dels clo u s compo a la o mació d'una haloclina mol ma cada, que a Guadalho ce és pe manen . Pel que a a les se es ca ac ens iques b iques, Guadal eba i Guadalho ce són eu b i- ques, la qual cosa es e lec eix en les al es concen acions de nu ien s i de pigmen s o o- sin k ics, i en la se a ele ada espi ació i ETS. D'al a banda, Conde de Guadalho ce es po conside a com a meso o ic, a més de no esgo a -se l'oxigen de l'hipoli nnion du an l'es iu. RESUMEN A pa i de 10s mues eos e ec uados du an e el pe íodo de mezcla (ma zo de 1988) y es- a i icación (se iemb e de 1988) en 10s es embalses del sis ema Guadalho ce, se analizan sus di e encias isicoquimicas y biológicas. Aunque 10s es embalses p esen an un con enido de sales disuel as ela i amen e al o, Conde de Guadalho ce es de aguas ca bona adas, mien as que en Guadalho ce son impo - an es 10s clo u os y Guadal eba se encuen a en una posición in e media. En es os dos 61- imos embalses la p esencia de clo u os de e mina la exis encia de una haloclina muy ma - cada, que en el caso de Guadalho ce es pe manen e. Desde el pun o de is a de sus ca ac e ís icas ó icas, Guadal eba y Guadalho ce son eu ó icos, 10 que se e leja en la al a concen ación de nu ien es y pigmen os, asi como po ene espi ación y ETS ele ados. Po el con a io, Conde de Guadalho ce puede con- side a se como meso ó ico a pa i de 10s mismos pa áme os, además de pe manece con oxigeno en el hipolimnion du an e odo el e ano. 28 J. ARMENGOL, J. CATALAN, N. GABELLONE, D. JAUME & AL. INTRODUCTION Al hough he e a e mo e han 900 ese oi s in Spain, only a ew o hem ha e c enogenic me omixis in he sense o Walke & Likens (1975). Among hem, wo o he ese oi s in he Guadalho ce Sys em, Guadal eba and Guadalho ce, ha e his ype o s a i ica ion. In con as , he hi d ese oi in his Sys em, Conde de Guadalho ce, is wa m monomic ic in consonance wi h he clima ic cha ac e is ics o he Medi e anean egion. As he ese oi s a e oge he (Fig. 1) hey a e submi ed o simila clima ic condi ions, and only he chemical composi ion o he wa e coming in o each one can be conside ed as a ac o o di e gence in hei ecology. The main chemical di e ences a e due o he concen a ion o o al dissol ed sal s and o he dominance o ce ain majo i a y ions in he wa e composi ion. This pape summa izes, om a compa a i e poin o iew, he empo al changes o each ese oi caused by he di e en o al mine al con en dissol ed in he wa e and he e ical dis ibu ion o chlo ide. As hese ese oi s we e p e iously s udied be ween 1972 and 1974 (Ma gale e al., 1976), he changes in he main limnological cha ac e is ics o each ese oi a e also conside ed. Guadal ho ce- VALLE DE ABDALAJIS Figu e .l. Loca ion o he Guadalho ce Rese oi s Sys em. A LIMNOLOGICAL STUDY OF THE GUADALHORCE RESERVOIRS SYSTEM 29 Table 1. Hyd og aphic and mo phome ic cha ac e is ics o he Guadalho ce Rese oi s Sys em. Conde de Guadalho ce Guadal eba Guadalho ce Al i ude (a. s. 1.) (m) 342 364 364 Volume (Hm3) 83 164 148 Su ace (ha) 510 796 759 Maximum dep h (m) 37 58 58 Mean dep h (m) 16,8 20,6 19,5 Ca chmen a ea (~m~) 270,5 -------.-- 1431 -------- A e age annual low (Hm3) 39,5 73,6 49,7 Residence ime (day s) 767 813 1087 STUDY AREA Guadalho ce Sys em is o med by h ee ese oi s placed in he con luence o he Guadalho ce i e wi h i s wo la ge ibu a ies (Tu ón and Guadal eba i e s); (Fig. 1, Table 1). They a e si ua ed in he NE oo hills o he Se ania de Ronda (Málaga, SE Spain) and ha e he hyd ological in luence o wo e y di e en a eas. Thus, Conde de Guadalho ce ese oi is loca ed in he Tu ón i e which d ains he ka s ic a ea o Se ania de Ronda. I s wa e composi ion is domina ed by sal s coming om he dissolu ion o calci e and dolomi e. In con as , Guadalho ce ese oi , placed in he i e o he same name, has i s ca chmen a ea in he endo eic zone o An eque a. As a consequence, he dissol ed mine al con en o he wa e is highe and i is domina ed by chlo ide and sul a e ions. In addi ion, a sp ing which is some imes subme ged (manan ial de Meliones) deli e s an a e age low o 20 1 s-' o dense saline wa e (80-140 g 1-1) (Rod íguez Pa adinas pe sonal communica ion) o he deep pa o he ese oi . As a esul o bo h kinds o inpu s, Guadalho ce becomes me omic ic. Finally, Guadal eba ese oi is si ua ed in an in e media e posi ion. I s d ainage basin also lies in he endo eic a ea o An eque a and i ecei es some deepwa e coming om he Guadalho ce ese oi . The e o e, he e is an accumula ion o saline wa e in he bo om and i also becomes me omic ic. METHODS The s udy o he Guadalho ce Rese oi Sys em was ca ied ou along 1988. Two samples we e aken in each ese oi , co esponding o he mixing (913188) and s a i ica ion (1519188) pe iods. Tempe a u e and conduc i i y p o iles we e measu ed in si u wi h a WTW conduc i ime e while pH and Eh we e de e mined a each sampling dep h wi h an O ion mod. 23 1 pH & Eh-me e supplied wi h Ross elec odes. 30 J. ARMENGOL, J. CATAL~N, N. GABELLONE, D. JAUME & AL. A LIMNOLOGICAL STUDY OF THE GUADALHORCE RESERVOIRS SYSTEM 31 Some analysis, such as alkalini y and hyd ogen sul ide by olume ic i a ion (S anda d Me hods, 1980) o he O2 concen a ion and he da k bo le espi a ion by Winkle 's me hod (Gol e man, 1969), we e i n nedia ely pe o med in o de o p e en quick changes in he samples concen a ion. Wa e samples we e i s ozen in liquid ni ogen and hen conse ed a -20 OC un i1 hey we e aken o he labo a o y. The ollowing pa ame e s we e measu ed om wa e samples in he labo a o y: S042- and C1- we e de e mined by Ionic Ch oma og aphy; Na, K and Mg by A omic Abso ion Spec ome y; Ca, Fe, Mn, Cu, Al and o al Si by Induced Coupled Plasma; Pa icula e o ganic ca bon (POC) and ni ogen (PON) by means o a Ca 10 E ba CNH Analyze and soluble eac i e phospha e (SRP), ni a e, ni i e a and ammonia wi h a Technicon Au oanalyze , acco ding o he me hod o G asho e al. (1983), modi ied o eshwa e analysis. The chlo ophylls we e de e mined by a HPLC sys em acco ding o Man ou a & Lewellin (1983), while phycobilins we e ex ac ed by he me hod o S ewa & Fa me (1984) and calcula ed a e Siegelman & Kycia (1978). Phy oplank on coun ings we e ca ied ou u using U e m+hl's me hod. Finally, he espi a o y elec on anspo (ETS) ac i i y was measu ed ollowing Packa d e al. (1989). RESULTS Rela i e ionic composi ion The Pipe diag am (Fig. 2) shows he main di e ences in he majo ionic componen s o wa e . Guadalho ce and Conde de Guadalho ce ha e espec i ely high saline and ca bona e wa e s wi h mino di e ences in hei ela i e composi ion along he e ical p o ile. On he con a y, Guadal eba has wo ypes o wa e : while in he mixolimnion he e is no a dominan ion, he moni noli nnion has a saline ype o wa e , e y simila o ha ound in he Guadal eba ese oi p oduc ion. The mal and chemical s a i ica ion Conde de Guadalho ce is he leas saline ese oi , because wa e is domina ed by ca bona e and calcium. The conduc i i ies ange be ween 378 and 441 @3 cm-1. In hese condi ions only he mal s a i ica ion is achie ed (Fig.e 3). In summe he e is an impo an ou low o deepwa e , he he mocline alls close o he bo om and a 2 m hick hypolimnion can only be ound. In Guadalho ce ese oi , he wa e coming om he saline sp ing o Meliones accumula es in he bo om, displaces he less dense wa e , and o ms a monimolim- nion. In win e his deep zone emains well di e en ia ed om he mixolimnion. Du ing he summe hea ing he he mocline plunges while he halocline aises due o he accumula ion o saline wa e . A he end o sum ne hey a e joined and only an hypolimnion can be seen (Fig. 3). 32 J. ARMENGOL, J. CATALÁN, N. GABELLONE, D. JAUME & AL. The Guadal eba ese oi has he mos complex pa em o s a i ica ion (Fig. 3). The wa e coming om i s ca ch nen a ea eaches conduc i i ies be ween 900 and 975 pS cm-1 and i ollows he same pa e n o he mal s a i ica ion as Conde de Guadalho ce. A he same ime, i ecei es deep saline wa e inpu s om I TEMPERATURE 1 . - CONDUCTIVITY, pS/cm Figu e 3. Ve ical p o iles o empe a u e and conduc i i y a 25 OC. A LIMNOLOGICAL STUDY OF THE GUADALHORCE RESERVOIRS SYSTEM 33 Table 2. Pea son's co ela ion coe icien be ween ETS and se e a1 en i on nen al pa a ne e s in Conde de Guadalho ce and Guadal eba ese oi s. N.S. wi hou signi ican co ela ion; *p < 0,Ol; ** p < 0,001. Conde de Guadalho ce Guadal eba ETS ETS Respi a ion 0,88** NS POC NS 0,98** PON NS 0,99** Chl-a 0,73* 0,97** Guadaiho ce ha a e accumula ed in a deep laye a he bo om. In hese condi ions he di e en ia ion o a mixolimnion and a monimolimnion is e y clea du ing all he yea , bu i is specially impo an in summe when an independen he mocline and halocline a e de eloped. Elec on anspo sys em and biological ac i i y The espi a o y elec on anspo sys em (ETS) is he biochemical machine y esponsible o oxygen consump ion. F om an ecological poin o iew, i s measu e gi es an es ima ion o he maximum espi a o y capaci y o o ganisms. As we had so many p oblems wi h o accu acy wi h he espi a o y alues ob ained by means o he da k bo le me hod, we ha e used he ETS da a as he main es ima e o he espi a ion. Un o una ely, samples om Guadalho ce ese oi we e no well conse ed, so we ha e no ETS da a o he wo sa nplings and o win e chlo ophyll concen a ion. In he o he wo ese oi s, ETS is highly co ela ed wi h chlo ophyll-a concen a ion (Table 2), showing he p ominence o p ima y p oduce s. In gene al, ETS alues we e highe in win e han in summe (Fig. 4). Thus, in he su ace wa e s o Guadal eba a, a e y high maximum alue o 230 pl O2 1-1 h-1 was measu ed due o a bloom o Anabaena a iabilis (291 mg Chl-a m-3). In con as , lowe alues we e ound in Conde de Guadalho ce whe e only 3,19 pl O2 1-1 h-1 we e a ained a he su ace wi h 2,7 mg Ch hl-a m-3. A he end o summe , esul s o ETS show an impo an dec ease o he po en ial espi a o y ac i i y, ha is o say, o ali e biomas. In Guadal eba he maximum alue measu ed in summe was 5,21 pl O2 1-1 h-1 while in Conde de Guadalho ce was o only 0.52 pl O2 1-1 h-1, ound nea he bo om (Fig. 4). When o he biomass ela ed pa ame e s a e compa ed wi h ETS esul s, he ese oi s show a di e gen beha iou . In Guadal eba ese oi ETS and chlo ophyll-a concen a ion a e well co ela ed wi h pa icula e o ganic ca bon (POC) and ni ogen (PON) (Table 2), showing he dominance o phy oplank on 34 J. ARMENGOL, J. CATALAN, N. GABELLONE, D. JAUME & AL. in he pa icula e o ganic ma e . In con as , ETS alues in Conde de Guadalho ce a e highly co ela ed wi h he da k bo le espi a ion. Al hough he co ela ion o ETS wi h chlo ophyll-a is also signi ican a he 0,05 le el, i is lowe han in Guadal eba, and he e a e no co ela ions wi h POC and PON (Table 2). These esul s sugges wo p ocesses wi h ega d o he pa icula e o ganic ma e : 1) In spi e o he phy oplank on being he mos impo an sou u ce o espi a o y ac i i y, ETS, pI 021-I h-I -101234 o I ' -w ? o O 1 o - I o 20 i. o 30 C. de Guadalho ce 0-0 Win e 0-0 Summe 40 ETS, pI 0~1-I h-I O 50 100 150 200 250 0-0 Win e 0-0 Summe 0-0 Win e 0-0 Summe 40 Guadal eba 0-0 Win e 0-0 Summe Figu e 4. Ve ical dis ibu ion o ETS ac i i y and chlo ophyll-a concen a ion. A LIMNOLOGICAL STUDY OF THE GUADALHORCE RESERVOIRS SYSTEM 35 zooplank on and decomposing bac e ia ha e also i s sha e 2) The e a e high quan i ies o o ganic ma e no ela ed wi h ETS, i.e. o de i al o ganic ma e . En i onmen al condi ions associa ed o Eh p o iles As a consequence o he he mic and haline s a i ica ion beyond biolo 'cal ac i i y, he h ee ese oi s show impo an g adien s o edox po en ial. Aile in win e he Eh p o iles a e no so s ong as in summe , in he me omic ic ese oi s some impo an di e ences be ween he mixolimnion and he Redox po en ial (Eh), mV 300 400 Conde de Guadalho ce 0-0 Summe 2 O e Guadal eba o e 0-0 Summe 40 U- Guadal ho ce o S 0. e-e 1 Su nme Figu e 5. Disí ibu ion dong he e ical p o iles o edox po en ial.