Zooplankton oxygen consumption and nutrient release in relation to species composition, animals size and enviromental conditions in the Baltic Sea during May and August

This pape no o be ci ed wi hou p io e e ence o he au ho s In e na ional Council o he C.M. 1992/L:21 Explo a ion o he Sea Session V Zooplank on oxygen consump ion and ñu ien eléase in ela ion o species composi ion, animáis size and en i onmen al condi ions in he Bal ic Sea du ing May and Augus by L. Pos eU), S. He nández Leon^), M. Gomez^, S. To es^), U. Mikka l),and A. Po illo Hahne eldl) 1) Ins i u ii Os see o schung (10W) an de Uni e si a Ros ock, Sees . 15, D-O-2530 Wamemünde, Ge many 2) Facul ad de Ciencias del Ma , Ap do. 550, Las Palmas de G.C., Cana y Islands, Spain KEY WORDS: zooplank on oxygen consump ion, ñu ien eléase, size classes, composi ion, en i onmen al condi ions, Bal ic Sea, sp ing 1988, 1990, 1991, somme 1988,1990 ABSTRACT: Zooplank on me abolism in e ms o oxygen consump ion and ñu ien eléase (ammonia, phospha e) we e measiu'ed in he Bal ic Sea, a empé a e á ea wi h high en i o mien al changes bo h in space and in ime. Plank on o he su ace laye we e analysed wi h balance measu emen s in 4 size classes be ween 50 and 1000 nm du ing sp ing in 1988, 1990 and 1991, in summe 19^8 and 1990 as well. The use o elec ón anspo sys em (ETS), and he Glu ama e Dehyd ogenase (GDH) ac i i y as indica o s o espi a ion and ammonia eléase espec i ely, enla ged he da a densi y and made a h ee dimensional esolu ion a ailable (May 1990, 1991). Da a a e in he ange o he la i udinal dependend magni ude. They e lec sligh in e annual, mo e seasonal and egional aspec s. Animáis size, empe a u e, ood concen a ion, and species composi ion in luence he speci ic a es. METHODS: Oxygen consump ion, in eqi e ed as espi a ion, and phospha e and ammonia eléase (exc e íon) we e measu ed in he Bal ic Sea, mos ly om Mecklenbu g Bigh o he no hem Go land Sea, some imes om he ansi i ion á ea (Skage ak / Ka ega ) o he Gul o Finland (Fig.l). De e mina ion we e ca ied ou by means o balance o "bo le" me hode (Omo i and Dceda, 1984). Samples we e ca e iíl coUec ed m he su ace laye down o he he mocline using a WP-2-ne , equiped wi h a special cod end o p e en , ha animáis ge d y. A e da k adap a ion o abou 3 o 5 hou s in máximum, unde oxygen sa u a ed condi ions, using wa e om he same s a ion, he plank on was ac iona ed in 4 size classes (55 - 100, 100 - 200, 200 - 500, 500 - 1000 ^im), washed ca e uUy wi h íl e ed seawa e o clean i om nu ien pa ióles, and ans e ed in 11 bo les. Bo les we e incúba e now in a con aine , cooled by sea su ace wa e , a a o a ing wheel (2. 5 pm). A leas one con ol bo le wi h he same íl e ed, and oxygen sa u a ed seawa e is o add, o be able o calcúla e he di e ence o oxygen and nu ien s o he bo les wi h and wi hou zooplank on a e he 6 o 15 hou s las ing incuba ion pe iode. The en ichmen o animáis in compa ison o in si u condi ions is abou 20 o 1000 imes, depending om he empe a u e. Finally oxygen, and nu ien s will be de e mined, he zooplank on s o ed in bu e ed o maline, o analyse he species composi ion, he d y mass, using con e sión ac o s as ecommended by BMB (1985). D y mass is needed o calcúla e he speci íc me abolic a es. Fo he calcula ion o in si u a es he in si u biomass is o de e mine in he abo e men ioned size classes. To be su e, ha all he di e en size classes a e quan i a i ely collec ed, ne s o 55 jim, 100 ^m and 200 ^m mesh size we e used o ha pu pose . F om he 200 jim ne he wo la ges ac ions we e p oduced. Wi h he same ne s plank on o he de e mina ion o me abolic a es by means o enzyma ic ac i i y (ETS, GDH) we e ca ched in 3 dep h le éis (su ace - he mocline, he mocline - halocline, halocline - bo om). Size ac iona ion and s o age in liquid ni ogen we e done immedia ely. ETS means Elec on T anspo Sys em ac i i y and is in ela ion o espi a ion, GDH means Glu ama e Dehyd ogenase, o be in ela ion o ammonium eléase. The single s eps a e desc ibed in a low diag amm (Fig. 2). The ETS assay was unned in he labo a o y acco ding o Packa d (1969, 1971), Owens and King (1975) and modi íed by Kenne and Ahmed (1975). The samples we e homogenized in e lon-glass a O - 4 C using a phospha e bu e 0.1 M, pH = 8 con aining T i ón X-100 (Sigma Chem. Co.) o he solubiliza ion o he enzymes (Owens and King, 1975). An aliquo o he c ude homogena e was incuba ed o 20 minu es a 12 •€ in da kness condi ions in he p esence o NADH, NADPH, succina e and an a i icial elec ón accep o , he e azolium sal INT (Biomedical Lab.). A e his ime, he eac ion is s opped wi h a solu ion con aining phospho ic acid and o maline and cen i ugued be ween O - 4 -C o 10 minu es a 4000 pm. The eac ion colou was measu ed a 490 nm wi h a u bidi y base line a 750 nm, and espec o a blank wi hou subs a es and ea ed as he sample. Fo he INT coe icien ac o , he alué o 1.42 was aken i om he mola abso p ion coe icien ob ained om Kenne and Ahmed (1975). Final ac i i y alúes we e ecalcula ed o he "in si u" empe a u e using he A henius equa ion and an ac i a ion ene gy o 15 Kcal/mol.-C (Packa d e al., 1975). Biomass as p o eins was de e mined acco ding o he me hod o Low y e al. (1951), using Bo ine Se o Albumin (BSA, Sigma Chem. Co.) as s anda d. The modi ica ion o he Low y me hod by Pe e son (1977, 1983) was used o he samples wi h low p o ein con en . The GDH assay was unned in acco dance wi h Bidiga e and King (1981) and Bidiga e e al. (1982), including ce ain modi ica ions: One millili e o c ude homogena e (same as ETS assay) is dilu ed in T is bu e , pH = 8.6 and cen i íigued (O - 4 -C) o 10 minu es a 4000 pm. In a Pe kin-Elme 551-S UVA^S spec opho ome e equipped wi h an 1 cm wa e -jacke ed cu e e he mos a ized a 12 •C, an aliquo o 0.5 mi o he supema an is placed in he p esence o NAD and ADP. When abso bance lec u e a 340 nm is s able, he assay is unned by adding glu ama e, and changes in abso bance we e eco ded con inuously o 2 minu es. The slope is p opo ional o GDH ac i i y. To al olume in he cu e e was 3.0 mi and NAD, ADP and glu ama e concen a ions we e 1.2, 2 and 40 mM, espec i ely (Bidiga e e al., 1982). RESULTS: 1. Me hodological aspee s: In gene al he e is a body mass - empe a u e dependency o me abolic a es. A coincidence wi h calcula ed a es in magni ude should be a quali y ma k o he own measu emen s, because 700 o 1200 obse a ions a e he basis o he Ikeda's (1985) equa ions. Using May and Augus 1988 as an example a sa is ying co espondence is o obse e: May Augus in i o empe a u e spec. oxygen consump íon pe indi iduum Hm^ O2/ Ind.* h spec. PO4 eléase pe indi iduum pM / Ind. * h spec. NH4 eléase pe indi iduum pM / Ind. * h obse a ion calcula ion obse a ion calcula ion obse a ion calcula ion 7.50 c 24.64 +/- 10.8; N=25 10.82 +/- 2.07; 15.17 +/- 7.76; N=27 4.85 +/- 1.22; 105.32 +/- 92.32; N=24 70.71 +/- 16.54; 18.3°C 15.06 +/- 7.76; N=16 17.99 +/. 1.67; 6.90 +/- 6.15; 6.25+/- 0.41; 57.94 +/- 50.38; N=14 112.57 4-/- 11.16; In May, a e o du ing he sp ing bloom pe iode, he obse ed alúes a e highe , han he calcula ed. In Augus he e is he opposi case, indica ing, ha empe a u e is one in luence, bu he nu i i e basis p obably o highe p io i y. Nex able includes esul s o co ela ions o 6 da a g oups, he compa isons (1) o oxygen consump ion and nu ien s eléase on he aw da ale el, (2) o ETS - and GDH - ac i i y on he aw da a le el, (3) o d y mass speci ic oxygen consump ion and nu ien s eléase a es ( aw da a de ided by biomass), (4) o p o ein speci ícenzyma ic ac i i y, (5) o (1) and (2), (6) o (3) and (4), using he May '91 da a as he basis: aw da a: 02 s. P04 02 s. NH4 P04 VSNH4 aw da a: ETS s. GDH d y mass speci ic a es: O2 s. PO4 O2 s. NH4 PO4 s. NH4 p o ein speci ic ETS s. GDH aw da a: O2 s. ETS NH4VS. GDH biomass speci ic O2 s. ETS NH4VS. GDH = 0.8309 = 0.9475 = 0.9035 = 0.6730 = 0.6582 = 0.4904 = 0. 5425 = -0.0577 = -0.0476 = 0.3353 = -0.0225 = -0.0937 p<0.00l p< 0.001 p< 0.001 p< 0.001 p< 0.001 p < 0.05 p < 0.05 N=21 N=21 N=21 N = 23 N = 23 N = 21 N = 21 N = 21 N = 21 N = 21 N = 21 N = 21 Co ela ions we e o expec in all he cases. The signi ican coincidence be ween he aw da a is a sa is ying indica ion o hei quali y. This is ae o bo h, he da a o bo le me hode and hoseo he enzyma ic de e mina ions . The eason o he lesse co ela ion o he d y mass speci ic a es a e p obably he calcula ed biomass da a. This is wo se in he case o p o ein speci ic ETS- and GDH- ac i i ies. No o mide s and is he missing co ela ion be ween he aw oxygen consump ion and he ETS ac i i y on he same le el. Tha biomass speci ic a es o bo h g oups in he las wo ows don' ma ch does inally no wounde . So he link be ween he wo me hods, shown in Figu e 2, is no ac i e now. Bo h da a se s ha e o be sepe a ely used. 2. Size classes: The smalle o ganisms show an abou 7 imes highe espi a ion a e compa ed wi h he la ges g oup (F¡g.3). The mean alúes a e om Augus 1990. The columns indíca e he s anda d de ia ion. 3. Ve ical s uc u e: The de e mina ion o he oxygen consump ion and he ammonia eléase in e ms o en2yma ic ac i i y in all he dep h le éis allows o es íma e he a e age e ical s uc u e o me abolic a es.. This will be done as ape cen age in compa ison o he su ace laye in May 1990 and 1991. The e we e no ema kable di e encies be ween he bo h yea s, be ween ETS and GDH, especially in he g oup o p o ein speci íc a es. La ge e ical g adien s a e o obse e in he in si u - g oup. The me abolic a e dec eases om he su ace laye successi e downwa d by ap oxima ely 30% pe dep h le el. The ETS esul s om 1991 a e p esen ed in he nex able as an example: su ace laye (up o he mocline) in e medía e laye ( he mocline o halocline) bo om laye (halocline o bo om) su ace laye (up o he mocline) in e medía e laye ( he mocline o halocline) bo om laye (halocline o bo om) ETS spec. 1000 - 500 ^im 100 143 101 in si u ETS 1000 - 500 ^m 100 61 25 500 - 200 ^m 100 85 69 500 - 200 xm 100 33 17 200 - 100 }im 100 79 80 200 - 100 nm 100 65 31 o al mean 100 102 83 o al mean 100 53 24 4. Regional Pa e ns: Figu e 4.1 includes en i onmen al pa ame e s, like empe a u e, salini y, chlo ophyll a e aged o he su ace laye , abo e he he mocline, and he diy mass o all size ac ions, he d y mass o he mos impo an class be ween 100 and 200 ^ini size, and he equency o he main axonomic g oups wi hin his class. The da a a e egional a e aged, one o en alúes a e he basis. SK&KG means Skage ak and Ka ega á ea, MB Mecklenbu g Bigh , AS A kona Sea, BS Bomholm Sea, S&CG sou hem and cen al Go land Sea, and NG No he n Go land Sea (c. . Fig.l). Figu e 4.2 includes biomass speci ic me abolic a es, oxygen consum ion, ammonia and phospha e eléase, ETS and GDH ac i i y, and he assimila ion numbe (p ima y p oduc i i y di ided by chlo ophyll concen a ion). Figu e 4.3 includes he in si u a es espec i ely.The a e ages a e he same like in Figu e 4.1. In a he mos cases a end is isible, cha ac e izing he la e sp ing si ua ion in he Bal ic Sea, wi h lowe empe a u es in he no hem pa , whe e he me abolic ac i e cen e is loca ed du ing ha ime, May 1991. The seasonal succession seems o be o ien a ed om he ansi i ion á ea o he Bal ic Sea o he no hem Go land Sea. The in si u oxygen consump ion and he phospha e eléase show a clea dec easing endency, in acco dance wi h he biomass pa e ns in Fig.4.1. 5. Seasonal and in e anual a ia ion To disc ibe hese a iabili y da a om wo seasons, May and Augus , a e a ailable, om a leas wo yea s. In Table 1 (Annex) he mean si ua ion is included o in si u d y mass, incuba ion empe a u e, in si u equency o Copepods and o Cladoce ans, he d y mass speci ic and he zooplank on in si u a es o espi a ion and emine alisa ion, pa ly o di e en size classes. Compa ing he May si ua ion 1990 was signi ican wa me , han 1988 and 1991. Also he equency o Copepods / Cladoce ans is di e en . The biomass o he la ge o ganisms is mo e de eloped in 1990, han in he o he wo yea s. The seasonal cycle s a ed ea lie in ha yea . This has no signi ícan in luence on he biomass speci ic me abolic a es, i hey a e a e aged o he whole Bal ic. Bu i has an inpu on he in si u a es, in dependency o he biomass. Rema kable di e ences a e o obse e in he biomass speci ic a es, i May and Augus will be compa ed. Du ing Augus he plank on composi ion is qui di e en in compa ison o May, he empe a u e. also. 8 I is o conclude, ha seasonal a iabili y is mo e signi ícan han in e annual. Tempe a u e may ha e an e ec , bu nu i ion and species composi ion o zooplank on is also impo an . Changes be ween 8 o 12_C (May 88, 91 / May 90) ha e a sligh in luence o he speci íc a es. A compa ison wi h da a collec ed in 1989 in he sub opical A lan ic show mo e signi ícan di e ences, bu on he basis o a 10 K empe a u e change! In ha case a speci íc oxygen consump ion a e o abou 13 mm^ 02 /mg d y mass * h in he A lan ic is o compa e wi h 5.55 om Augus 88. This is a eIa iono 2.3. (F om Ikeda (1985) a ac o o 2.8 is o expec , i an á ea o 21° N (A lan ic) and ano he o 50° N (Bali e Sea) will be compa ed. ) LITERATURE CITED: BIDIGARE, R.R. and F.D. KING, 1981. The measu emen o glu ama e dehyd ogenase ac i i y in P aunus lexuosus and i s ole in he egula ion o ammonium ex e ion. Comp. Biochem. Physiol., 70 B: 409 - 413. BIDIGARE, R.R., F.D. KING and D.C. BIGGS, 1982. Glu ama e dehyd ogenase (GDH) and espi a o y elec on- anspo -sys em (ETS) ac i i ies in Gul o México zooplank on. J. Plank on Res., 4: 895 - 911. HERNROTH, L. & H. VIL JAMA A (Eds.), 1979. Mesozooplank on biomass assessmen . BMB Publ. No. 6 . I5pp. IKEDA, T., 1985. Me abolic a es o epipelagic ma ine zooplank on as a imc ion o body mass and empe a u e. Ma . Biol.. 85: 1 - 11. KENNER, R.A. & S.I. AHMED, 1975a. Measu emen s o elec ón anspo ac i i ies in ma ine phy oplank on. Ma . Biol.. 33: 119 - 127. LOWRY, P.H., N.J. ROSENBROUGH, A.L. FARR & R.J. RANDALL, 1951. P o ein measu emen wi h a Folin phenol eagen . J. Biol. Chem.. 193: 265 - 275. OMORI, M. & T. IKEDA, 1984. Me hods in ma ine zooplank on ecology. John Wiley & Sons. New Yo k, Chiches e , B isbane, To on o, Singapo e. 332 pp. OWENS, T.G. & F.D. KING, 1975. The measu emen o espi a o y elec ón anspo sys em ac i i y in ma ine zooplank on. Ma . Biol., 30: 27 - 36. PACKARD, T.T., 1969. The es ima ion o he oxygen u iliza ion a e in seawa e om he ac i i y o he espi a o y elec ón anspo sys em in plank on. Ph. D. Thesis, Uni . Washing on, Sea ie. 115 pp. PACKARD, T.T,, 1971. The measu emen o espi a o y elec ón anspo ac i i y in ma ine phy oplank on. J. Ma . Res., 29: 235 - 244. Enz mology. Vol. 91. Academic P ess, pp 95 - 119. ACKNOWLEDGMENT: We would like o hank he c ew o RV "A. .Humbold ", o RV "P o .A.Penck" o hei help, he Chemical Depa men o he Ins i u e o Bal ic Sea Resea ch, Wamemünde, o many nu ien analyses, Anneli Pos el and Heide Sandbe g o he nume ous zooplank on de e mina ions, he lOW Da a Cen e, p o iding empe a u e, salini y, chlo ophyll da a, and assimila ion numbe s, and he BMFT, because he measu emen o 1991 we e suppo ed by his Minis y (Con ac No.:03F0030A). N = mg d y nass-m'' í incuba íoo empe a u e/oC equency o Copcpods/ % equency o Gadoce ans Oxycen coosomp ion d y mass !^)eci ic/ mm' Oi-mK"'-h'' in si u/ mm' Oj-mg'-h'' ', Pbospha e eléase d y mass sped íc/ nM-mj-'-í -' in si u/ : >íM-m-'-d' A lmonia eléase ; d y mass speciñd nM-mg-'-h-' 1 in si u/ ;iM-m'-d' . Size ac ion//im May '88 26 27 7,5 76 16 9,12 7,24 5,40 3,50 34,68 42,66 >200 4,19 Í2,T~ 43 46 13,93 1.4 4,30 0,43 53,48 5,38 May'90 16 19,50 __ 4.32 _ - 1 4Ú 10 13 41 12 23 4,77 8,95 32,33 2.23 0,93 E - 4.56 3,12 7,65 21,70 1,46 0.87 '-"2,76 16,51 29,76 38,65 7,73 3,08 E » 16,19 1000- 500- 200- 100- 500 200 100 55 >20Ó •" • May'91 12 4.77 8.59 '"8;6 So 34 11___22__ 8.16 5,18 0,93 1,07 19,26 3 0 8.20 3,70 E-.6.5 3,78 1.92 0.43 0.40 2,19 1,01 E - 2.03 30,48 17.35 3,49 3,58 22,67 10,48 E = 18.44 1000- 600- 500 200 >20b 200- __100_ 1,61 0 0 18,28 0,71 5.01 0,19 23,06 0,89 100- _55 _ Aug. '88 16 100 18,3 Mi 70 5.55 __13,37 2,55 5741 21,00 53,61 >200 _J,86 31" 67 , 5,26 1,29 0,65 0,14 24.66 5.25 1000- 500 65.37 18.2 29 70 6.29 8,48 ' 1,49 2.34 20,08 31,50 500- 200 >200 Aug. '90 5 12.51 29 69 11,61 3,98 T m 15 30 2,60 0,79 E - 3,38 15,25 4,64 E - 43.38 200- lOQ I 09 41 57 39,68 1,64 4,06 0,11 71,70 1,99 100- 55. _ Table: Co npa ísons o mean alúes o en i onmen al condi íons. zooplank on biomass. equency o Copepods and PhyHopods. speci ic and in si u mc abolic a es in May I988.I990. I99I and in Augus I988.I991.