pruder 1986 aquacultural-engineering

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Aquacultural Engineering 5 (1986) 115-121

A quaculture and Controlled E utrophication:Photoautotrophic/Heterotrophic Interaction andW ater Q ualityGary D. Pruder

Ocean ic Institute, W aimanalo, Haw aii 9679 5, US A

A B S T R A C TIn this pa pe r, par allels are drawn between p rocesses that un derlieeutrophication in natural systems a n d processes that underlie producti-vity an d stabili~' in aqua culture produ ction systems. I t is suggested thataquaculture is a fo rm o f controlled eutrophication in wh ich successionis" restricte d by m an ag em ent strategies including loading density,aeration, water exchange, type o f fertil izer an d various feeds an d feed -ing regimes.The importance o f gas exchange inhibition in aquatic systems a ndthe interactive role of volatile organics and plant nutrients in determin-ing the deg ree of balance that exists between gross" photosynthesis an dtotal respiration is discussed. The im pa ct o f photoa utotrophic/hetero-trophic interactions on water quality is stressed.

I N T R O D U C T I O NT h e t e r m " e u t r o p h i c a ti o n ' w a s o r ig i n a ll y a p p l i e d t o t h e a c c u m u l a t i o no f n u t r i e n t s a n d i n c r e a s e i n o r g a n i c m a t t e r th a t a r e a n a t u r a l p a r t o ft h e s u c c e s s i o n o f l a k e s . R e c e n t l y i t h a s b e e n a p p l i e d n o t s o m u c h t ot h e n a t u r a l s u c c e s s i o n a l p r o c e s s a s t o t h e g r e a t l y a c c e l e r a t e d o n er e su l ti n g f ro m h u m a n i n t e r fe r e n c e ( K e e t o n , 1 9 7 2 ) .

H u n d r e d s o f t h o u s a n d s o f t o n n e s o f o r g an i c m a t er ia ls f r o m u p l a n da n d t id a l m a r s h s o u r c e s e n t e r c o a s t a l w a t e rs a n n u a l l y (B ig g s a n dF l e m e r , 1 9 7 2 ). T h e i m p o r t a n c e o f th is i n p u t to t h e d e t ri ta l f o o d w e bh a s l o n g b e e n r e c o g n i z e d . C h a n g e s i n i t s p r o p e r t i e s s u c h a s v o l a t i l i t y

115Aquaculmral Engineering 014 4-86 09/8 6/S0 3.50 - Elsevier Ap pl ied Sc iencePublishers Etd, E ngland, 1986 . Printed in G reat Britain


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l 1 6 G . D . P n ~ d e r

(b iochemica l oxygen deman d) and ca rb on t o n i t rogen r a t ios , li nkedwi th inc reased l eve ls o f p l an t nu t r i en t s f rom o the r sources , con t r i bu t eto t he an th ropogen i c degrada t i on o f coas t a l wa t e r s . The i n t e rna lcyc li ng o f d i s so lved oxyg en and d i s so lved ca rbo n d iox ide m us t becons ide red w i th nu t r i en t cyc li ng and r emine ra l i za t i on i n unde r s t and-ing aqua t ic sys tem s t ab il it y and p rodu c t i v i t y i n t he dev e lopm ent o f asa ti s fac to ry mana gem ent s t r a tegy fo r w a t e r qua l i t y improv em ent .Evidence indica tes tha t the dec l ine in f i sher ies and o ther resourcesappea r s l inked i n some w ay t o p l an t nu t r ien t en r i chm en t , mea sured a sto ta l n i trogen and pho sph orus ( J aworsk i, 1981 ). Th e o rgan i c ma te r i a lenter ing coa s ta l waters ra pid ly loses i ts ident i ty throu gh phys ica l andb i o l o ~ c a l b r e a k d o w n . O x y g e n i s c o n s u m e d a n d c a r b o n d i o x i d e a n dinorganic p lant nut r ien t s a re re leased a nd serve as input mater ia ls fort he g rowth o f a lgae and o the r aqua t i c p l an ts . O the r p l an t nu t r i en ts a r eadded d i rec t ly to coas ta l waters by ef f luent f rom secondary was te-water t rea tm ent p lant s and a gr icul tura l runof f .Biggs (1981) and Brush e t a l . (1981) i l l u s t r a t e an an th ropogen i cef fec t as ev idenced by the sh i f t s in vegeta t ion in the ChesapeakeW atershed, USA (64 00 0 squ are mi les ) dur ing the pas t four centur ies .Fores ts and heav i ly vege t a t ed wo od land s have g iven way to u rbanareas , h ighways , pas ture la nds and fer t il i zer - in tens ive agr iculture .These sh i f t s , a long wi th the increase of secondary was tewater t rea t -m ent p lant s , have m os t l ike ly resul ted in a subs tan t ia l chang e in theabso lu t e and r e la t ive l eve ls o f b io log i ca l oxygen de m and and p l an tnu t r ien t inputs to the es tua r ine sys tem d ur ing h i s tor ica l t ime.

M A N A G E M E N T S T R A T E G YUnl imi t ed i npu t o f vo l a t i l e o rgan i c ma te r i a l s and t he i r b iochemica loxygen demand l imi t s t he ca r ry ing capac i t y o f any aqua t i c sys t em,natura l or cons t ruc ted , as the resul t of unacceptably low di sso lvedoxygen conc en t r a t i on . L ikewi se , i npu t o f p l an t n u t r i en t s can l im i t anyaquat ic sys tem's car ry ing capac i ty , resu l t ing in a lga l b lo om and decayand upse t of pH and d i sso lved oxygen. In cont ras t , input of vola t i l eo rgan ic ma te r i a l and p l an t nu t r i en t s i n p rope r p ro po r t i on a r e r equ i r edfor na tura l in tens ive aqu at ic pro du ct ion , as ev idenced , in par t, by there la t ive ly h igh p roduc t i v i ty o f nea r sh ore wa t e rs a s co m pared t o op enocean wa te rs . Th e re fo re , t he b iochem ica l oxygen deman d (BO D) and


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Aqua culture an d controlled eutrophication 117p lan t nu t r i en t i npu t shou ld be cons ide red t oge the r when dev i s ing am anage me nt s tr a tegy fo r aqua t ic p rod uc t i o n sys tems .A q u a t i c p l a n t p h o t o s y n t h e t i c m e t a b o l i s m c o n s u m e s c a r b o n d i o x id eand con t r i bu t e s d is so lved oxygen (DO) , he lp ing ma in t a in t he D O andpH of aqua t i c sys t ems . The new p l an t b iomass en t e r s t he food web .Highly product ive aqua t ic sys tems ( f rom es tuar ies to aquacul tureponds) a re order ly : there exi s t s a ba lance in oxygen product ion andd e m a n d , a n d b e t w e e n c a r b o n d i o x i d e p r o d u c t i o n a n d d e m a n d . O t h e r -wise DO and pH would not remain wi th in acceptable l eve l s . Aquat icpro du ct ion sys tems are u nd er sev ere gas exchange l imi ta t ions ascompared t o t he i r t e r r e s t r i a l coun t e rpa r t s wh ich func t i on i n t hea tmosp he re , w hose com pos i t i on is no t subs t an ti a ll y a f fec t ed by m e ta -bol ic processes . Therefore aqua t ic and te r res t r i a l sys tems presentqu i te d i f f e ren t m anag em ent p rob l ems .Nixon ( 1981 ), in d i scussing c hanging v iews of rem inera l i za t ion andnut r ien t cyc l ing in coas ta l mar ine ecosys tems , s t a tes "The ma jor t rendhas been an i nc reas ing apprec i a t i on fo r t he complex i t y o f t he p ro -cesses involved, inc luding som e m arke d changes in our assessment ofthe impor tance of bac te r ia wi th respec t to smal le r an imals and in ourpe rcep t i on o f t he a s soc i a ti on be tween bac t e r i a and pa r t icu l a te m a t t e rin the sea '. F ur ther, " . . . the fac t tha t e u t ro ph ica t io n app ears to be a ninc reas ing p rob l em in m any e s tuar ie s is d r ama t i c w arn ing t ha t an th ro -pogen i c nu t r ien t i npu t s can o ve rwh e lm the r ecycl ing and r emine ra li -zat ion p rocess es in coastal waters' .Sc ient i s t s and enNneers working in the f i e ld of in tens ive aqua t icproduct ion sys tems (mar icul ture) have a l so changed the i r v iewscon s iderab ly over the p as t t en years . S igni f icant ly , they hav e recent lyiden ti fi ed t he m anage m ent o f in t e r ac t i ons be tween he t e ro t roph i c andph o toa u to t ro ph i c mic roorgan i sms a s t he key t o ma in t a in ing s tab l eand p roduc t i ve aqua t i c p roduc t i on sys t ems . In t he Sea Gran t Aqua -cu l t u r e P l an 1983-87 r e sea rch on con t ro l o f aqua t i c sys t ems wasgiven top pr ior i ty over a l l o ther a reas inc luding nut r i t ion , gene t ics ,d i seases , eco nom ics and po l icy .Aquacul tur i s t s have long suf fe red the pa ins of aqua t ic sys temins tabi li ty , h ighly var iable pro duc t iv i ty and mass m or ta l i ty due to lowlevels of dissolved oxygen. I t i s only recent ly that I have come torea l ize tha t i t i s imposs ib le to separa te the feeding of aqua t ic orga-n i sms f rom env i ronmenta l con t ro l (P rude r , 1981) . The re i s w ide -sp read apprec i a t i on fo r t he impor t ance o f ba l anced i npu t o f vo l a t i l e


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1 18 G.D. Pruder

organic m ater ia l s and inorga nic p lan t nut r ien t s . I t wo uld be prof i t ab leto i n it ia t e coop e ra t i ve r e sea rch amo ngs t t hose a t t empt ing to m a in t a inthe qua l i t y o f mar ine ecosys t ems and t hose a t t empt ing t o p roduceaqua t i c p l an t s and an ima l s i n i n t ens ive p rodu c t i on syst ems . Ou r goa l sa r e i n p r inc ip l e s imi l a r and o ur p rob l ems nea r ly i den t ica l .

D I SC U S S IO N A N D C O N C L U S I O N STh e i n t e rac t i ve ro l e o f va r ious vo l a ti le o rgan i c m a te ri a ls , BOD andp lan t nu t r i en t i npu t s t o i n t ens ive aqua t ic p rod uc t i o n sys t ems i s be ingexp lo red fo r many t ypes o f aquacu l t u r e p roces ses . By f a r t he mos tp roduc t i ve aquacu l t u r e sys t ems depend upon t he i npu t o f o rgan i cfeeds tuf f s , of ten was te mater ia l s . Aquat ic microbia l organisms arethough t t o fun c t i on a s an ex t e rna l ' r umin an t s t om ach ' (P rude r, 1983),serv ing to increase the nut r i t ive va lue of the input organic mater ia l .Ac cord ing t o Sch roede r (1978 , 1979) t he p rodu c t i v i t y o f aquacu l t u r ef ish po nd sys tems depen ds upo n t he add i t ion , i n p ro pe r p ropo r t i on , o fchemica l fe r t i l i zers and organic mater ia l s . Schroeder repor t s themax imum f i sh y i e lds a t t a i nab l e i n ea r t hen ponds i n I s r ae l w i thou tsupp l emen ta l feed a r e:

- - with no fe r ti li zer, 1-5 kg ha - ~day-~ ;- - wi th chem ica l f e rt il ize rs , 10 - 15 kg ha - ~da y- ~;- - wi th chem ica l f e rt il ize rs and ma nure , 32 kg ha -~ da y- 1

Excess ive addi t ion of chemica l fe r t i l i zers to pond sys tems resul t s inmass ive a lgal b loom , sub seque n t d i e -o f f, unaccep t ab ly l ow D O l eve l,and mass m or t a li t ie s to f ish . T he p ro pe r am ou n t o f chem ica l f e rt il ize ris de pen de n t u po n t he t ype o f ma nu re be ing u t il ized .Cass ine l l i e t a l . (1979) de ve lop ed a p r e l imina ry mode l fo r d is so lvedoxygen in sh r imp mar i cu l t u r e ponds :

D O / A T = - O D E C - O C R E S - O P R E S + O P H O + O W EN D+ O W T U R

whereO D E C is t he r a te o f oxygen con sum pt ion by sh r imp r e sp i r a ti on ,O C R ES is t he r a te o f oxygen con sum pt ion by a lga l r e sp i ra t ion ,O P R E S is th e r a t e o f o x y g en c o n s u m p t i o n b y p h o t o s y n th e s i s,


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Aqt~acul ture an d contro l led eu troph ica t ion 119OP HO is t he ra t e o f oxygen p rod uc t i on by pho tosyn thes i s ,O W IN D is the r a t e o f oxygen i npu t f rom a tm osph e r i c d if fus ion , andO W T U R is t he r a te o f ne t oxygen i npu t f rom wa te r t u rnove r.Cass ine l l i e t a l . (1979) used t he empi r i ca l r e l a t ionsh ip deve loped byRedf i e ld e t a l . (1963) fo r r e sp i r a t i on and pho tosyn thes i s t o e s t ima t eva lues fo r t he p r eced ing mode l . The Redf i e ld equa t i on i s

(CH 20)tt}6(NH 3)IsH3P O a + 1 3 8 0 , respirationp h o t o s y n t h e s i s(

1 0 6 C O , + 1 6 H N O 3 + H 3 P O ~ + 1 2 2 H , OFrom thi s equ a t i on i t c an be show n tha t f o r each g ram of ca rbo n f ixedin photos ynth es i s , 2 '6 g of oxyg en are prod uce d. S imi la r ly , for eachgram of o rgan i c m a te r ia l decom posed , 1"2 g o f oxygen a r e consu med .I t i s a l so ev iden t t ha t t he p roduc t i on and consumpt ion o f n i t rogen ,phosphorus , oxygen and ca rbon d iox ide a r e r e l a t ed . Cass ine l l i e t a l .conc luded t ha t t he ma jo r source o f oxygen to a sh r imp po nd is pho to -synthes i s and the m ajor ox ygen s ink is a lga l and bac te r ia l resp i ra t ion .Indeed , sh r imp r e sp i r a t ion and d i ffus ion f rom the a tm osph e re p l aym inor ro l e s in t he oxygen ba lance . Th ese f ind ings supp or t o u r co n t en -t io n t h a t b a la n c e b e t w e e n h e t e r o t r o p h i c a n d p h o t o a u t o t r o p h i c o rg a -ni sms is im po r tant in aqua t ic sys tem s tabil ity . T her efo re , there la t ionship be tween vola t i l e organic mater ia l s and p lant nut r i en t s ,which cont ro l these processes , i s impor tant . The degree of s imi la r i tybe tween sh r imp ponds , f i sh ponds and ce r t a in pa r t s o f nea r shorewa te rs r em a ins to be dem ons t r a t ed .F u r t h er e v i d e n c e s u p p o r ti n g th e i m p o r t a n c e o f p h o t o a u t o t r o p h i c /he t e ro t ro ph i c i n t e r ac t i on shows t ha t i n tens ive p ro duc t i on o f al gae i sof ten carbon l imi ted , (Bidwell , 1977; Pruder , 1978, 1981; Pru der e ta l . , 1978 ; P rude r and Bo l ton , 1979 ; Gordon e t a l . , 1982 ; Kawasak i e ta l . , 1982; T ar i feno-Si lva e t a l . , 1982) . Go ldman e t a l . (1982) d i sputesca rbo n l im i t a t ion , bu t h i s a rgum ent s a r e no t conv inc ing . T he r equ i r edaddi t ion of carbon i s s imi la r to the long recognized need to addni t rogen, phosphorus , v i t amins and t race meta l s for p lant growth . Inthe t e r r e s t r i a l env i ronment one se ldom i s conce rned w i th t he ca rbondioxide for the p lant s or oxygen for the animals . Whi le in the aqua t icenv i ronment adequa t e l eve l s o f ca rbon d iox ide and oxygen a r e con-t inua l ly threa te ned .


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120 G. D. Pn~derI n p o n d c u l tu r e , w h e r e s u p p l e m e n t a l f e e d is a d d e d , t h e u t i li z at io n

o f c h e m i c a l fe r ti l iz e r s is o f t e n l i m i t e d t o p o n d s t a r t- u p . T h e f e e d sp r o v i d e a b a l a n c e b e t w e e n B O D a n d p l a n t n u t r i e n ts . I n a p p r o p r i a t er at io s o f B O D t o fe r ti li z er i n p u t c o u l d c a u s e a b r e a k d o w n i n th e p o n dp r o d u c t i v i t y a n d s ta b il it y . T h e r e is g r o w i n g r e c o g n i t i o n o f t h e n e e d t o' f ee d t h e s y s t e m ' a n d n o t j u s t t h e f is h o r s h r i m p .

R E F E R E N C E SBidwell , R. G. S . (1977) . P ho t osy n th es is and l igh t and dark resp i ra t ion inf reshw ater a lgae . Can. J. Bot., 5 5 , 8 0 9 - 1 8 .Biggs , R. B. (1981) . Freshwater in f low to es tuar ies , shor t and long te rmp er sp ec t iv e s . Proc. N atl. Syrup. on Fresh wa ter Flo w to Estuaries, U S F i s ha n d W i l d l i f e # / F W S / O B S - 8 1 - 0 4 .Biggs , R. B. & Flemer , D. A. (1972) . The f lux o f par t icu la te carbon in anes tuary . Mar. B io l. , 12 , 11- 17 .Bru sh, G. S., D avis, F. W. & Sten ger , S. A. ( 1981). S e d i m e n t A c c u m u l a t io nand the His too ' o f Sub me rged A qua t ic Vegeta tion in the Pa tuxen t and WareRivers: A Stratigraphic Study. Th e Jo h n s Ho p k in s Un iv e r s i ty , Ba l t im o r e ,

Mar y lan d .Cassinel l i , R. D. , Fa rnsw orth , J . T. , Sw eat , V. E. & Ston er . D. L. (1979) . Varia-t i o n s in d i s so lv ed o x y g en co n cen t r a t io n in m ar i cu l tu r e p o n d s : a p r e l im i -n a r y m o d e l . I n : 7bird A nn ua l Con ference on Tropical and Sub-7?opicalFisheries, ed . R . N ick e l so n , Tex as A & M Un iv e r s ity .G old m an , J . C. , Az ov , Y., Ri ley , C. & D enn et , M . (1982) . Th e e f fec t o fp H inin tens ive microa lga l cu l tu res . I . Biomass regu la t ion . J. Exp. M ar . Biol .Ecol . , 5 7 , l - 1 3 .G ord on , M . S ., C ha pm an , D. J ., Kaw asak i , L . Y., Tar i feno-Si lva . E . & Yu, D.( 1 9 8 2 ). Aq u acu l tu r a l a p p r o ach e s to r ecy c l in g o f d i s so lv ed n u t r ien t s i nseco n d a r i ly t r ea t ed d o m es t i c was t ewa te r s. I V . W at. Res., 1 6 , 6 7 - 7 1 .Jawo r sk i , N . A . ( 1 9 8 1 ) . So u r ces o f n u t r i en t s an d th e sca le o f eu t r o p h ica t io np r o b lem s in e s tu a r i e s . I n : Proc . Sympos ium on Nutr ien t Enr ichment inEstuaries, eds B. J . Nei l son & L. E . Cron in , Humana Press , Cl i f ton , NewJe r sey , p p . 8 3 - 1 1 0 .Kawasak i , L . Y. , Tar i feno-Si lva , E . , Yu , D. & Gordon , M. (1982) . Aquacu l -r u ra l a p p r o ach es to r ecy c lin g o f d i s so lv ed n u t r i en ts i n seco n d a r i ly t r ea t edd o m es t i c was t ewa te rs . I . War. Res., 1 6 , 3 7 - 4 9 .Kee ton , W. T , (1972) . Biological Science, 2 n d ed n , W. W. N o r to n & Co . , NewYork , p . 673 .Nixon , S . W. (1981 ). R em inera l iz a t ion an d nu t r ien t cyc l ing in coas ta l m ar ineecosystem s. In : Estuaries and Nutr ients , eds B. J . Nei l son & L. E . Cron in ,H u m an a Pr e ss , C l if to n , New Je r sey , p p . 1 1 1 - 3 8 .


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Aqu aculture and contro lled eutrophication 121Pru d e r . G . D . (1 9 7 8 ) . E f f ec t o f p H , ca rb o n d i o x i d e , o x y g en an d l ig ht i n t en si tyo n t h e g r o w t h o f Thalassiosira pseudonana, c l o n e 3 H , a n i m p o r t a n t f o o d

fo r b i v a l v e mo l l u s can mar i cu l t u re . Ph D D i s s e r t a t i o n . U n i v e r s i t y o f D e l a -ware . 100 pp .P ru d e r , G . D . (1 9 8 I ). A q u a t i c p ro d u c t i o n s y s tems : a lg ae. In : Nursery Cultur-ing of Bivalve Molluscs, ed s C . C l au s , N . D ePau w & E . J a s p e r s . G h en t .B e l gi um , p p . 2 1 9 - 2 6 .P ru d e r , G . D . (1 9 8 3 ) . Fo rew o rd . In : Second International Conference otzAquacul ture Nutr i t ion , ed s G . D . P ru d e r , C . J . L an g d o n & D . Co n k l i n .O c t o b e r 1 9 8 1 , R e h o b o t h B e a c h , D e l a w a r e .P ru d e r , G . D . & Bo l t o n , E . T . (1 9 7 9 ) . T h e ro l e o f CO ~ en r i c h m en t o f ae ra t in gg as in t h e g ro w t h o f an e s t u a r i n e d i a t o m . Aqu acul t , t re, 17 , 1 -15 .Pru d e r , G . D ., Bo l ton , E . T . & Faun ce , S . R. (1978) . S ys tem con f igura t ion andp e r f o r m a n c e b i v a l v e m o l l u s c a n m a r i c u l t u r e . I n : Pro c . Nin th Ann . Meet .World Maric. Soc., A t l an t a , p p . 7 4 7 -5 9 .Red f i e l d , A . C . , K e t ch u , B . H . & Ri ch a rd s , E A . (1 9 6 3 ) . T h e i n f l u en ce o fo rg an i s m s o n t h e c o m p o s i t i o n o f s eaw a t e r . In : The Sea: Ideas an d O bserva-t ions on Progress in the Stu dy o f the Seas, ed M. H . Hi ll, In te rsc ien ce PUN.,New York , Vol . 2 , pp . 26-77 .S c h r o e d e r , G . L . ( 1 9 7 8 ) . A u t o t r o p h i c a n d h e t e r o t r o p h i c p r o d u c t i o n o fmi c ro o rg an i s ms i n i n t en s e l v -man u red f i s h p o n d s an d r e l a t ed f i s h y i e l d s .Aquacul ture , ! 4, 3(i)3-25.Sch ro ed e r , G . L . (1 9 7 9 ) . F i s h f a rmi n g i n man u re l o ad e d p o n d s . I C L A R M -SE A RC A Con[: on Integrated A gricu lture-A qua cultu re Farming Systems,1978 , Mani la , Ph i l ipp ines .Tar i feno-Si lva , E . , Kawasak i , L . Y . . Yu , D. & Gordon , M. (1982) . Aquacu l -t u r a l ap p ro ac h es t o r ecy c l i n g o f d i s s o l v ed n u t r i en t s i n s eco n d a r i l y t r ea t eddo m es t i c w as tew ater . II . I t~ tt . Res., 1 6 , 5 1 -7 .

pruder 1986 aquacultural-engineering

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