Document XO7aQBOZ9O1jyxbaOeNd6GLRR

. portion of i!ic (itciMiland record over ),isl VlHi veins. If anything. the simulai puts the next minimum farther inti) iuiiiii' ilum would estimates based i-il\ on analogies with previous "cy. I Ini'. mIickms the exact dale of the minimi shown in (he extended natural titoc (i ig If is uncertain. its oeKtiie in the ticvI decade i> probable - i,do of \x .1 r itt i hi* Ivy >ml i lie mini mum N-i open to question As the ( O. cHoct dominate. the mKcrtoint' here lies :il\ hi the estimates of futmc chemical u-e and in the magniludc of tlio warmper unit of execs' ul mosplnri iv C'Oj. major point of the argument is that r the past fO vent* the warming trend i.* t. U, hits been more than countered i natural uioiinp. (hi.' compensation !,'i long continue both hcc.iu.se of the ,* growth of tin- <*0. effect and because naiuial cooling util almost ccttamly t [>o:tom out We limy he in lor a cliic surprise 1 he onset of ibe era of iml.avd warming may he much more r . tic than in the absence of natural ch ic i .uiations, tc aii!i iculiiiral consequences of ibis mg warming are not obvious {neither V implications in global sea level). A ledge of the mean global umijwraturc ns Intlc iiIhhii the ruiiifitJ! patterns in liic! grain-producing regions, ( here is douhl, however, lhai libs gradual nine will lewd to> hunocs in the pattern obal piev ipilaiion. Out ellnm in un.mil and eventually to predict those ees must he icdnuhlcd. Wu l xt ! S, Boi r ki K ./;*-/><*/n-m' rieo/iiyfro/ OhwrvtilorY 'leparlmcnt tif (leoloyjctd St7*tnes. mbtu Unlvctuiv. ,,dv*. AVtc York tOVbd *'f(.'iW*it'Mlri Nulr M. ik.m.K.I S | l.ilim.iri |l li ( l.nceil (' (` .......I, li too ( s.ft*. ..# K Ii.hLi.'M, 1 if lYi>k' I'niv. I'.ov N.-w Ui'ffl. itu.. I'l!1(, p. v. VC bktvs^,tia S. J iuhnacn. II < Iimikii. N htrdd dttmUmd |X. ?*. Hl'M .lV II s,Iwoifcr and W , W Kfll.iyp, rn ( hrmntrr )('.'< <** 'flitil'J.Ai'rr. S l. ti, tPW- . \r y..ik. in i), i> .'(M, 0. Vm..m*lo mm! i....a.,.y ,cmm s.< li, MU5 tt72fc R. A. 1C. ,/iA.m/.'2l. V. (l%*h Med , , ,n In .( I'.Utmsm, (/ Ikt SuhrttnH f.Jrrl - iinv ii I niliottiikiM.il Siiutk v thin mil) uf .. MwUmw. OHO. SVicn> MW. 7sX : ,l W M.kdull. Jr. in <<l.~t:.t I II,: n .ifhi- ''a'ioU t'nitutma. S. f. Sinni'i. I a (KvM. >! la. Vnliriluiklv ;uut .S;irin.'i-Vulstp. <* \ (WM. uv Man'. r*|mri <m ih.' < il M.iUhrwi, VC VC KcJl.ip<'.<< I) Hi>tuiv.'o. . ,X|I t !>(>.. (Wtu.Uf.v.'Mass. lV7tt. pp. . H.hl |(.?;VC W k.'II.M t 'fill S II S. Imrulur. IM. 11(0 (l`)7J|, l!.,mlHnlS II. SehiwMlvr, < 173. I'H I s.IiihhIui ji.iI H I) Duim'il, Amhiit 4, .1. . ,a.r ,mi1 K I Wi'llu .-il.t. J >!">> V., 24 O. I Ill O.l'l > /<>.;.<, I till lilt l lnil`ll'\ W v:.,-ii.,, \e vc k n.>cr, < i> Hi.i.hkoh. iV,I| IS. . . i 'il ruliMili.c. \t .1ss . mil) |. ?l|t; . . | ..ml !t I VV 11in-J .i li|. ./ > lmn> Sti. 7 S H S'cl.pitidtr, 7 Aimm Set. in presv OC . IK^J, p J| H li H C A. Ikrtuhl Jr , an4 C I). Knlinf, in Curium ihid, p sfi and the Sunfhrrr, (> M. W'ihnIwcU und If. V. I'c- II. tinned Nations U nr/J Ara.''fi-Sui'p/if' V'mi.'u at C4n. t:.dv (rciknieat Infminiilinn Cenier. OlWee of Inl.wiiMii.m irnifi-. IIS Aiumic hnci^y l urn- Paprr', Srnu I lllm.nl NiImihk N<* Y.,.k m.'o I'fVJ, WiMUft, K> dshtnpton. O.C , IV73), p M. 12 J M. W.U'hrll dud /nir '/.>.r.spA '( 9. W S Hr.^aer. Y U. I.i. T. H. Penp. m Impiner- (UNLSCd Pan. m.ti. pp i/ii rsr. irm / Mj/i ran tin- Oi rum. O W Hoik), i d. n w Dnn.i-'jrd M/m 16, 436 (I9A4). I M.rhi.u (W.ky N< > >ik. 1971). p, 27. nd f. I orij. Rhhi'ii hr I Punt) 4 (No "1.4'/ 10. II tloim 4rid b hiikixun, in J hr .4mnni hi rr tinii (19711. ihr Sra ... M-.imn. Ninthr Mrniiitiul IKilwnr. H. 14. S J J.ilinsrn VV l)4.i'C4d, H II Cl.imun r' (' BWin. IM t K.'AtffHvr tnslitulu fres. Nc* Y.irY. 1 itngk.iv. U . V aiurr il.tin,l I 2,15, 4?9 (19?.*) 19S9), p I t(tr I. M.ichd, m Vhr C'*unpie ('Arin- I V t'llliv.-lx.rlly.l- U|,r. Sl' l' Slh.ll'ldv! Uk Njimn- .h <>; ihr <1. fu. I'lm-TudiHB' ol the JHm Nntx-t *1 (.cider Inf Vim.upturn.: Kese.o.h .ci .cry S)ni|Minium. I> DrxiMin jnd 0 Jnencr. lets. bx'lpful in '.m>:liieiiii' oul .|uc'lii>' I li.id .ih V.iik, 1971). p. 12t; C.) Kcelin,.. in ..(Oil >I> I.mn, r.III.lull'. t lliu rlfen. i>( ( O, < Ar.ii.iiM'm rht l.iiHrr Nlimit/'hrrr, S I. Hnvniil. rfn.l dusi I hi' u.uk 4s u|>p.'Onl tn iuiih.iii l\t tt'tenwn. "sfj. Yotk, 1S7\), tl'ap f. 1. M.uh- A1 (I I I )21.S5 s u It iln US A lomu t-nvfpy l '.* i:. m Curhun and ihr U<u\nhtrf, G. M. Wii.Kt. miniion Hits .. ii.ninhuiii.ii No 2J4X (rui.i Ilk' wH *nd t V. Peon, hdv fTrchnn:.) Infor- (onuni Ik-hrio (.cnlii(>n'nl(JhM'rv.iliiiy Hialiim C'mtur. Ollictr >i( Infurnmhnn Survioc, US. Ali.mii; F.ncrsy Cnmirmwon. 'Wuxli.nj.i.m, lOMnrch I97 ..v<! ; sfdy IK7J Chlorinated Hydrocarbon Pollutants and Photosynthesis of Marine Phytoplankton: A Reassessment Abstract. The chlorinated hydrocarbon* /)/>'/'and l*CH\ tp-zt\rhh/>muiaihipln`n\l\I, ubiquitous poh'uiunii of ike marine environment, have been nbu-rvcd in rvdwe the cell division rate of marine phytoplankton, thereby nuiirecth reducing the total pfajfmiuthetic carbonfixation in treated culture*. The photosvntltettc capacity ofeach cell hui imi affected. Total marine photosynthesis *ill likely remain untUminithed by thew* i .;mpound.*, although alterations in phytoplankton communities through .u-lrctnc touatv could affect herbivore /Hipu/ations. Several pcrsuicm and ubiquitous chlori nated hydrocarbon pollutants of the inaiiiic environment, most notably ^Cll's (jmlychlorinatcd biphenyls) and DDT {U. I -(richloi u-2,.7-l)is(/-chloropiicn) IK'thanc), cun reduce the growth rate (/. 2) and have been reported to reduce photosynthe sis {2d) in some marine phytoplankton cultures. The decrease in carbon fixation observed in treated cultures (2-^), as mea sured by the incorporation of '`C-lubclcd bicarbonate, could have resulted from an inhibition of the photosynthetic process it self. or it may have been due to a depressed growth rate, that is, fewer cells photosyntheswjng in treated than in control cul tures. I conducted an experiment lo determine whether algal photosynthesis on a per ceil basis, as well as on n per culture basis, wns affected by ffC6*s or DDT. The organ* ochiorinc concentrations used were above those found in natural waters (J); no at*tcmpi was made to determine the toxicity of cnvirnnincmally realistic concentrations of these compounds, as was done elsewhere (d). T he purpose of this study was to estab lish whether, in ;<lg;>c, phoiosyntlictic car bon fixation itself is inhibited or whether just growth is affected by these chemicals. The three Hlgi-i species studied (7) wore selected on the basis of their sensitivity to chlorinated hydrocarbons; the growth of Thuiassiosirtt p\e;.,!onana and Skelrtonema eostatutu. common murine diatoms, is affected by I'C M's ami DOT (/), and photosyntbeiic carbon fixation in cultures of Cocctdiihu* huxleyi and the two dia toms is reported)' reduced by 1)1) I (_\ .(). Culture conditions anvl procedures have been described elsewhere {#). Mcthunolic solutions of PC M's (Arnefor 12M) or 1)1)!' were injected (/) into the cell suspensions at time zero to give initial PCB concentra tions of 10 ug/hter (parts per billion) ami DDT concent rations of 50 pjb tn the medi um liquid volumes of methanol were add ed to the control cultures (d). I K'sc otg.inoebUmne compounds, at similar concen trations (or doses per cell), have been teported to substantially depress the net carbon fixation in monocultures of these algal sjiecies {2. j). AI 4K hours. I ml of medium was icmoscd fiom each tube so that cell counts could be determined {10), 0.2 uc of (,JC|NaHCO, was added (//). and the cultures were incubated as before for about S hours 1 he same procedure was also earned out for dark controls. I he veils were then gcnilv filtered through OK .-m Milliporc libers and washed wuh lilterul seawater, the rudmactivily ol the tilteis was counted in a liquid scintillation coun ter (Tri-Carl). Put kard). The entue evpeunient was repeated with ihe io diatuni species. Table l preseni' ihe 4X-hour cell vou.it>. phoiosyitthetie Cerium fixation )w:t vvUwk. anil carbon uptake per cell (.) Ihe d.i.L uptake of '`C, which varied with each sj>ecies (living 2 pervent ol ihe illiunin.iitil /. /ivt'ur/ouuiui "C uptake, less than ' pertenl will] S costatum .iiiil 10 peieciH with (' htixlcyt), was '<jli!<jct':d from the i.ov fS l`)7S HONS 062687 I .idle J tried. of l'('U'(l() pplH anil DOT (50 pfb)on three specie* of marine algae. growth w.is measured m term, of ;<ll density ai IX h-nr.. :),< .j. bun uptake |Hi culture was measured after 5 Hours of incubation, ami the carbon uptake (u) has the units cpm pet I90.MX) cells per hour Number V I the mean* of four replicate cultures arul are *how with then 95 percent confidence intervals (I4). Single clantticuiiiin aruKsii of vurunce f/b, mj,v l that Kto*tb ami carbon uptake per culture by treated cells differed from cootcul cullutc* for T pirudonono (P < .0251 and for S costatum (P .. ,t j but uptjke per cell in treated cultures did not significantly (Jitter from conlrof culiure values for either species Control C h^lty, cultures did n.it mticamly differ from treated cultures for growth, carbon uptake per culture, or carbon uptake per cell I Cells per milliliter (x it>*> Mean % Control "C uptake per culture {cpm/19 ml) Mean % Control ' upiak r per sell Mean "o Cool Nil `C uptake fa cefUtept m 7' />iri4,J<iv'<u C ontrol 10.76 i-0X9 100 1014 ^ 226 .00 15 7| t 3 7) 100 / pseu./tmumi PC Its 6 77 v 1.94 M 5)8 t- 1X0 57 IJ4V r HI 86 T pstiiJoniiiiii 1)1)1 3.18 * 1.74 .10 295 e 10b 28 16.37 * 3 63 104 S.ctitlulum Control 22 7K *4.13 MX) 6584 *1494 !Q0 44 39 v 4.MJ t0 .V costutum DOT 4 17 t 0.52 IX 1074 * )47 16 45 86 * 14 26 103 (' Austrti Control 3 2 e 1.30 100 404 * 93 100 2) 22 * K.d* (00 C hwtlevt PCB's 3 17 * 0.64 97 403 * 187 100 23 10 * 5 44 99 ( Aut/rii DDT 2.XX * 1.04 XX 376 7ft 9} 24 55 * 5 18 106 urn 109 102 ion 94 counts lo give the net values shown in Table 1. Because differential growth rales during incubation could cause inaccurate estimates of carbon fixation per cell, a was determined by considering the specific ex ponential growth rate of each cultute: ---------C------\{N/r){t"' - 1)1 (t) where C denotes the radioactive counts per minute (cpm) per 19 ml of culture, H is the cell density at 48 hours, r is the growth rate in cell divisions per hour (12). /' denotes the incubation time with the "C-lubeied bi carbonate. and n is the carbon uptake rate per ceil (in units of cpm per cell per hour) l/J) The total photosynthesis in cultures of T. pstutionnna and 5. costatum was re duced by the chlorinated hydrocarbons, confirming earlier results {2, J). Carbon fixation per T pseudununa culture was di minished 48 percent by the PCB's and 72 percent by the DDT. but growth was also diminished in the treated cultures. The ,4C uptake per cell ( Table I). a direct assess ment of the photosynihetic response of the cells to the organochiorine compounds, was unaffected by the chemicals. Thus, what appears to be 72 percent inhibition of T. pstudonanas photosynthesis and *4 percent of 5 catmium'* photosynthesis by DDT is merely a reflection of growth inhi bition by this compound, rather than of photosynihetic inhibition per se. These re sults, confirmed in the repeat experiment l i able I), might explain earlier work (2-4) which showed a reduction in the incorpora tion of "C-luheleil bicarbonate per culture by these compounds. The growth and photosynthesis of C. huxleyi were not af fected by either chemical, in contrast with pnst findings (3). Skeletoaema costatum whs killed by the PCB's; both growth and photosynthesis stopped, and the integrity of the cells j> completely disrupted. No other morphological differences between treated and control culture cells were ob served under the light microscope. 4(4 The photosynihetic decline in treated cultures was thus due to reduced cell divi sion rates. The mechanism by which the chlorinated hydrocarbons affect diatom growth is as yet unclear, although recent studies with T. pseudonana suggest that PCB's may inhibit membrane-bound en zymes involved in nitrogen metabolism {Id). Although total photosynthesis in the diatom rnonoculturet wag reduced by the PCB's and DDT. phoiosytuheiic carbon fixation in nature would likely remain unaffected by these compounds, even if present at concentrations many times the current environmental levels. Resistant au totrophs would probably replace sensitive species, as demonstrated in mixed cultures of marine phytoplankton with low {6) and high (13) concentrations of PCB's and DDT. Alterations in the species compo sition of phytoplankton communities, caused by persistent pollutants, such as the chlorinated hydrocarbons, could result in deleterious effects on marine ecosystems if the resistant species that become dominant were an inferior food source for the resi dent herbivores. The most likely con sequences of chlortnuted hydrocarbon pol lution for the lower marine food web would therefore stem from qualitative, not quantitative, changes in the herbivores' food supply. Nicholas S. Fishfr Woods Holt Oceanographic Institution. Woods Holt. Massachusetts 02543 References and Nun t. J. L M osier tttd., Science |7S. 191 (1972). 1. D. w Mentel.). Anderson, A. Randlke. tM 147, 1724(1*70) ). C. f Wwutt. It , iM. IS*. (474 (19**! 4. E. i Luad.fthyrofo|i A Moor* and R C f larms, Halve* (Lot*. 1240. )$6 (1972); Mftf ftuttut Buff S. 174(1*74) 5. C. R Harvev, w. (j Stemhiuer, t M. Teni. Set- met 1X0. 6*3 (1*7)): P. t. Okiffs, L. J Albright. S. Y S/em. Can Viffohwi IS, IJ*1 0*7') T T Schmidt. R W Rixhrou*)* F (ire,*. But! e,m Cui*m Coxicoi 6, 2)50*71), G. O Vt.lh IlMtCi F l.rt. Water Ret S.H07(I*7I) A N. S md. Mirmh trot I. )*(>*>7t); N S. Fivher. ih,u. Stale University of New York. Slonr Brook (1*74). 7 Clone* " IH" of T ^irM/rmgw. "Sker of 5 roire- ium, and "BT^ ' u( C Xiutrvi w<(ol*irK,l (i,.,n K H L GwIUrd. Wut<J Hole Oeeanue jphn. i< iitiuimn cultuie vOttenim* An culiure, .r- n * N Jj fivher. L. 8 Graham, fc ) CjifKmtr i. * Aarure | 141, 50) {WT'.j cell 1 wert atouted *l (im (or e*.htttliuie >utM Hy fcrw nmcaljimt i.-i, - i, uni m a sterile ju. vi^orouslr virrint >' lun*j Uhifnrm cell *u,pcrM,rm. Md aweptM ,IIv a<>- pvnm| 20 ml per ih (li mt capucn)!. (ktit were four repli.ile lubes per lrealme<*> [ * Methanol tkuwu m p*eUtntary t*t*e*irnrm. } lo have no effect on pk<iioraitWM* itr cprwtk Hit I euAcemralrohS and punly ol ihe chlonnuied i>- ' drocarbon tiock, were vhevkad kf ctevteunAip ( tore (fj* chromuioyraphy tJ). I he PC II vntHentra- i ihwi was lowenhao ii* reported *alh*hi/<ww.i i l to 2 mt/lner- in inai<r |V Zilko StJt t.u I roe CiiMan Toxuot 5. 27* ()*7n>), *ne*ri'"<, DDT concentration cxeeded I 1 pph. its -,iluhii,c, i in water (K Acree. M Berova. M C Huwm.n I r /<W <4em. II. 278 (I94))l DDT al conceivui-on* atceedmx its -olohiM, I lief can affect slfal |iowih in a <t*4're*p">> | itiunner (7. 2), rnher l*v inAvancine srvw'k m in- I unriittolved stair or b> beinf rumily <nd >tu.i!. I compieiety incorporated into the cell*. o> wt<.^ casa it would nui vrystellire in tha inedium ! Ftpertmenul evidence wppom ike toiler ci ' rnnationjA Sodergren. Dtkur 19. I!0(l9**i| i Speirr-Lavy ownoptwl counter (hemaoium 1 eter) *a used II. 7het'*C'|NaHCO' -eldissolved m tienlerli.nKnl I water. pM * J. ^nd Mrd (htwigh ab 22- ,,m NU- | lipore fitter before u,e A ayrmne u u>rd io j>U j 0 2 ml pel culture. | 12 The relue nf r takutmed xxurdmg io << method of R. W EppteyendJ. D H SinikNud lie AJvaoett in Mierotnohny 4/ tht 5i. M It 1 Droop and t ) P Wood, Ede. (Academic PrcM,. Loodun. l*Mi.vol l.p. 2)|. I 1) In Eq. I it it atsumed ihal in each caliure, 1 C up take tltpendem on ihe number of etili. ih.i ir>e j uptake rate per cell remained cqnsuni, jnd ihri I growth proceeded at a constant 'ate. ' (The 1 elapsed lime of ihe etllire e<pernem -a* \ than ihe eepvnennel rowih pha* of ihr*e given ih <Am mmat condilion, (J) j L'.nler ihes* 1 aasumptHrnt. I eC/di .aN,* "`e, for 1 > 48; 'nieguiinf. we obtain C - n.\ J t" *"dt . (*/*)(" l) where T is ihe nmc ji Ihe end of ihe eiperimrni for each >pli.]ie and /' - T - 48 14 N S. Fisher ft R. L Cu.Uurd, C F WWik per prtwnled t the American Chemical Soon? meetui|. Philadelphia. (97); N. S Fisher end I 5 Murphv, in prenaranun. 15. I l MoiXl.h S Filher. C. F Wurler.5.<rvr 174. })J( 1*72) 16. ft R Sakai and F 1 ftoWf. Sw-.i.y (Viw>* San Francisco. 1*6*1 11 Supported b> the Sarah Mellon Scei'r I uumtation, i lhank 9 l Dempcrv .nd A C C.(< Jl.irvev fur u,e ^1 iheir i(uiw cn. ) W Farnneton. W K > end C t- Wurvier fa. vupge Woods Hole (>rca>tographic 26 March l*7V. rev.id 2l May t*75 SCIFNI. I vnl n" MONS 062688