Pollution and inshore phytoplankton

Pollution and Inshore Phytoplankton A survey of data concerning the seasonal periodicity of p h y t o p l a n k i o n in inshore waters around the Briush Isles has shown thai several studies were made close to large urban centTes where the effects of man made pollution could be significant (Wells, 1938 for S o u l h e n d on Sea; El Maghraby, 1956, for Whitstable, Savage, 1965, for S o u t h a m p t o n Water; Rees, 1939, for the Bristol Channel o i l Cardiff). 'There is a singular lack uf information about TABLE I 'The more p r o m i n e n l c o m p o n e n t s of the inshore p h y t o planklon in Cardigan Bay observed during 1965 to Iq68.

Biddulphia mobihensis Cos( inodist us e¢ t entricus Cost rnodrscus grani Paralia ~-alcata Podosira stelhger Spring (I) Bacillarm paxilhJ:'r (2) Chaetoceros sp. Coscinodiscus radialu~ Dllylum brightwelhi Lauderia borealis Thalassiosira spp Winter

the p h y t o p l a n k t o n o f inshore waters away from such c enires. Oul studies o n the p h y i o p l a n k t o n of the inshore waters of Cardigan Bay - chiefly based on a station 2 miles west of A b e r y s t w y l h - indicate cerlain aspects of the occurrrence of diatoms which are noticeably different from the data q u o t e d for the o t h e r Ioc'alirles. Our observations, together with some data from the coaslal waters of Ireland, form the basis of this aslicle. The clue[ c o m p o n e n t s of the p h y i o p l a n k t o n observed during 1965 to 1968 are s u m m a r i z e d in Table I. Each year there was a bimodal outburst of diatoms in the spring and early s u m m e r (Sykes and Boney, 1969), which coincided with dechnes in the c o n c e n t r a t i o n s of nia'ate, phosphate and reactive sdicate. A smaller outburst was observed each autumn. Comparison ol these results with those From o t h e r Iocalilaes, using samples which are appreciably separated in time, presents obvious difficulties. One noticeable feature of the data from the IocaJities on the south east and south coasts of Ihe Briush Isles, however, was the c o m m o n o c t u r r e n c e , in appreciable numbers, of certain species at the different stalaons. 'Thus, Actinoptychus senariu.h

Belh'rochea maUeus, B,dduiphia aurita, Lilhodesmium undulatum, Melostra s p . , Rhizosolenia setigera, Skeleton ema coslatum and Streplo|heca tamesis were recorded from the different Ioca.lides, but were either absent from the A b e r y s t w v t h records, (BIdduiphia aurita, Lithodesmium undulatum), or presenl in very small numbers and con. stltuled an insignificant part of the d i a t o m flora. The relatJve abundance ol certain of these species in the o t h e r localities may have been a refletUon o f the greater quantities of nutrients and other growth factors in the polluted waters (Hendey, 1964). For example, El Maghraby (1956) recorded winter maxima for phosphate and nitrate which were sis limes greater than the m a x i m u m values obtained at A b e r y s t w y t b , and ten Limes higher Ihan those for the Enghsh C 'hannel (NeweU, 1959). T h e spring 3at bursl at Whitstable was d o m i n a t e d by vast numbers of B,ddulphla aurita. For S o u t h a m p t o n Water the spring growth consisted almost entirely ol $keletonema costalum

Summer (Early)

Rh,zoselenm shrub~olei Guinarcha jTa¢ cida R h~z osoh'nia stolter/'othil Ceratium ~usua Phaeoe'ystis pouch,q, (2) Leploc~lindricus danicus R hlzosolenia deliculata Peridinium sp. A u t u m n Biddulphia alterna~ Butdulphm mobiliensis Butdulphia regra Chaetoceros sp. Co st inodisc us grant Thalassionema nitzscoides

S u m m e r (I)

TABLE 2 Phosphate, diatoms and chlorophyll a, between Wttklow and Dublin Slalkm number

Dale

/ag.al of phosphale/l.

Dtalom cells/lOml,

pg chlorophyll of all.

0968)

2547 2549 2351 2552

15.5

i.o5

-

o.174

14.3 ,,

2.0 1.54

427 55

0.648 0.972

,,

1.36

-

0.528

15.5 ,, 16.3 . ,, , ,, ,, ,, ,,

0.56 0.23 0.5 0.96 1.50 0.90 0.85 3.50 2.66 5.40

-

O.

,, ,,

5.6fi 0.38

,,

2577

19/16

2556 2557 25fi9 2565 2564 2565 2566 2368 2569 2370 2371

2574 2875 2376

79 65 61 191 210 148 223

152

0.69 0. I I O. I I

-

571

-

-

0.85

566 765

i£5

0.85 1o

-

19.3

0.45

84

-

Figuses are for slatlons in the coastal waters b e t w e e n Wicklow and Dublin. Station n u m b e n are as in the ship's log, with the e x c e p t i o n of 19/16, which is a Decca I'Lx made during a m a g n e t o m e t ~ transect. All biological data are for surface waters. 38

1.0

N

O.S

|0

D

~

)3.5

"2.5

t¢

f

o,J

t"

I

\

.,tO

,,/,'""'

'W'.

Fig. 2, Lines lcqrurlg slmila.l' numbels ol dtaloms and flalp'Uales pe~ 10 rnJ. uI surlace walev. , Diatoms, • • I'laip'Uates.

Fig. I. Lines jolrun K slmd,u phosphale ,concenlraDons, (/./Rat of pho.~phal¢/I.) ~om slallorl.,, near the Insh L'oasl. D, Dublin; W, W,ckluw. (Savage, 19h5). 'Thus certain species ol dJaloms are possibly associated w i l h high com.entraLions of nuUr,ents ,n inshore water's at cerla,n seasons. Some further evidem.¢ I'or the Iocaliz.ed abundance or Lert,un dJatoms m relati~.~n to inshore waters subjeLled to the ¢l'l'ects o1' land polluticm was obtained during a short 4.ru,se on the RR~S .John M u n a y in the western Irish Sea during March 196/4. Twenty stations were worked I'rom a pc.nt south east ul' Wzckl.w tu norlh ol Dublin. Samples were laken from Ih¢ surface at all stat,ons, and rrom various depths. Phosphate was delerrnlned by the melhod ol' Murphy and Rdey (1962), with calibratt~.ms as recom mended by Slrlck.land and Parsons (IqbS). All deter mlnatlons were made at sea using a Llnicam SP 600 speclrophotometer. In adchtlun, 20 ml. ahquots o1' each sample were healed with Lugol's tocbne and subsequently exarmned I'or phytoplank Ion after I..hei r return to Aberystwylh. The daLa are summarized in Table 2, and are shown dia6"rrammaLica.lly in Figs. I and 2. As expe~Lled, con~.enrraLJons ol phosphal¢ were high close inshore, notably in the viclrulzes o1' Wic.ldow and Dublin. The

existence oi' a coastal band or phosphate rich water which became progressively wider north oi" Dublin, and which was continuous with a tongue oF p h o s p h a t e - n c h water e m a n a n n g in an easterly direction, indicated a northerly l]ow oi' water. L,ss (1969) has c o n f i r m e d this northerly flow near' the Irish Coast from studies on salirdUes, reactive silicate concentraLions, and observations on current flow. Diatoms and flagellates The dJslrtbutlons o1' diatoms and flagellates are shown in Fig. 2. 'There was some ton'elation between the larger numbers of phytoplankton organisms and high concen Iraluons o1' phosphate, except I'or the region ,mmedialely north ol" Dublin where large numbers of diatoms were associated with relatively low contenlrations of phosphale. This low concenlralion of phosphate may have been a result ol uliltzalJun by plants. 'This is a region o1" tidal slack (Adn'draJ[y, Iq43) and the large population of plants may have resulted From the absence of strong t,dal currents. V,.u',at,ons in the results ol' deterrnJnalions oF chlorophyll ,, may have been due to the populattons of flagellates which arc not recogntzably preserved by trealmenl w~Lh rod.the, so that the numbers o[ small flagellates counted may nol have been representalave. A I'utlher analysts o1' the diatom populations al the various sial.ions Is given in 'Table 3. The diatom spe4.ies associated ,n large numbers with relatively high concen 39

l,ral,ions of p h o s p h a t e were Biddulphm aurita, Chaetote'ros lorenzianum, Cv¢lotella striaLa, N~tzs,:hm c l o s t e n u m , Paraluz sulcata, Skehotonema costaturn and Thala.ssro.~ira norden.~k~old~L Of these, only the lychopelagic Parlm has been f o u n d m ¢ o n s , d e r a b l e n u m b e r s o f f Aberysl,wyl,h. 'The (.It t'urrent'e ol B~dduiflhia aurita and S k e l e t o n e m a t oslatum would lurl.her mdical,e their associal,mn with inshore waters subJected to [ugh levels of ,ndusl,riaJ and domesl,ic pollul,,on m add.it,ion to r w e r b o r n e land run off. 'T'hm ~s not to suggest a specif,c r e q u i r e m e n t Ior high concenl,ral,ions of p h o s p h a t e w~l,h these d i a t o m s . Phosphal,e may be a con venlenl,

measure

of

the

concentration

of

nul,rienl,

f r e e from laJg~ scale indusU'ml a n d d o m e s t i c p o l l u t i o n some residual effecl,s from the earlier heavy mel,al p o l l u t i o n of the rsvers Rhesdol a n d Ysl,wyth m a y have to be l,aken inl,o artounl,. T h e heavy p o l l u t i o n of these rivers by mel,aJ was a result of the lead m i m n g o p e r a t i o n s in N o r t h CardJganshire whit'h t e a s e d early in the twenl,iel,h c e n t u r y . Leaching f r o m the spoil heaps of these inland m i n e s caused severe pollution of these rivers, to the e x t e n t t h a i l,he R . h e i d o l was barren 35 years ago ( N e w t o n , 1959). Extens,ve work d u r i n g m a n y years has resull,ed m recolonizal,,on by p l a n t s a n d a.mmals a n d the re esl,ablishment of l,he river as a fishing ameml,y ( N e w l o n , 1944, 1959). This factor o f n v e r . b o m e heavy metal p o U u t i o n was r e f e r r e d l,o by Lloyd ( 1 9 2 5 ) m an e ~ l , e r s t u d y of phyl,oplankl,on in Cardigan Bay w h e n certain Features of d i a t o m o c c u r r e n c e a n d absence from the flora were ascribed to poss,ble effects of lead a n d zinc pollul,,on. A l t h o u g h pollul,,on o f l,he Rheidol has largely been e l , m i n a t e d , some zint is still b r o u g h t d o w n by the Ysl,wyl,h, (up l,c) 3 p.p.m, soluble zinc has b e e n r e c o r d e d ;

in

p o l l u t e d waters, but the fat curs governing l,he a b u n d a n c e of t e r l , a m s p e o e s m a y be m o r e mchrecl,. All,hough it w o u l d be valuable t o o b t a i n r e f o r m a t i o n on the a b u n d a n c e of p h y t o p l a n k l , o n ,n inshore wal,ers away from large u r b a n cenlres, m a n m a d e effecl,s ,n adchtion to land run off may slall t o m p l i t a l , e the sHualJon. Thus, while A b e r v s t w y t h a n d the n e a r b y waters of Cardigan Bay are

TABLE 3 N u m b e r s of dial,oms/10 ml. in surlace samples from various st,at,ions. 2349

23,51 2357

dctmoptvchus senariu~ d,~terioneP,, faponu'a d,~fenoneila kariana A steromphalus hooken Bau illana pa.~dll/er Bu~duiphsa aurita Chaetocera~ cunpi~etum Chaeto¢ eros d, uer,tum

-

-

Chatyfot'~ro$ I ( f f t ' n ~ I t a n u m

-

-

--

--

2

23.59

.

.

2365

.

-

.

-

.

.

II

. .

2

et (, Pntf~ct£b

-

.

.

I0

7

2 12

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17

I

-

I

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20

-

71

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.

9 .

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3

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-

.

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2

19/16

-

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3

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2 .

--

2375

3

6 .

19

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2374 2

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I

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b

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2371

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2370

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--

Chaetocrro; pseudo('rinffum Chaefoccros ;,'mplex Chaetocero~ sp. Coscinod.cus

2369

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2366

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Coscinodiscu~ fram Cobt'lflodl$c I~

Itut~mg6 Coscinod.t.ua radm G'~clotella stnata l~plonci~ sp. Fras//ar~ sp. Gmmmatophora manna

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vat. ~ubtduslm. Gvrosigma sp. Hemmulus hauckil Lauderm borealu Melo~ra sp. Navwul~ sp. Nit~schu~ clmtenurn IV. delu ati~,nmo IV. ,fvna vaa. v~da Paralm .su&a t a l~'nnularm sp. Pleurosigma norman,i Pieuro.gnm sp. PodosJra ,stelhger Rhi~o~olenu seh'gera RhtL osolen,,, ,;hr.bsoh'l SkeleionenuJ costatum Synedra sp. 'FhalaJsso~ra ,'ondenaata 'E deci~erLs T. norderukiulddJ Thalm.~o~Jra sp. 'Frachynet~ a~pera V a l . o-~p~'Ya

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personal communication from the South West Wales Rtver Board). The extent to which these forms of river borne pollution can affect inshore marine phytoplanklon ,s not known. A further noUceable ommission from our records should be menuoned. Eucumpm zodiacus' has been recorded in tonsiderable numbers at various points on the Welsh coast. In autumn 1968 it was the most prominent speties m the diatom outburst in the sea near Anglesey. We have only two recordings for this species m the Aberystw3,th neighbourhood for the 3 years of the survey, and eath time it constttuted an =nsigrdftcant component of the flora. It is known to occur ,n muth larger numbers at Iotaltltes north and south of Aberystwyth. Ideas about the reasons for the absence ol ttus species must rem,un speculattve. Whether =t may also serve as an 'indicator' spectes must await more detaded investigation. Foi studies on pollution and the phytoplankton of inshore waters there seems to be no 'base line' for the assessment of comparattve data. Simultaneous studies near large centres of popular,on, and at stadons where only land run ofl is of sigruficance, would be useful contnbuhons. We thank the officers and crew of the RRSJohn Munay for the facilltJes and help given during the cruJse m the southern Irtsh Sea ,n March 1968. Department of Botany, University College of Wales, Aberystwy Ih, Wales.

J. B. Sykes A. D. Boney.*

Admiralty (I 943) Irish Sea. 'Pocket Tidal Stream Adas', Hydrographic Department. EIMaghraby, A M. (1956) A qualitat,ve and quan

* Present addJeaa: Deparlment of Botany, The University, Glugow.

tttatnve survey ol the plankton of the Thames Estuary, Whttstal')le (Thests, LInw London). Hendey, N.I. (19bq) An mtroduclory atLounl of the smaller algae of Br,ttsh coastal waters. V. Batillariophy,.eae, 'F,sh. Invest. L o n d . ' Sertes 4 : 317 pp. Lass, P. S. (1969) Reactive sd,cate concentrations m the Irish Sea, 'J. Mar. Biol. Assoc. LIK', 49 : 577 588. Lloyd, B. (1925) Marine phytoplankton of the Welsh Coasls, w,th special reference t . lhe Vltlnlly ,~t' Aberystwyth,'J E, o l ' , II~ q2 112. Murphy, J. and Riley, J. P. (1962) A modified single solut,on method I ol the determmat,on o1' phosphate in natmal waters, 'Analyhca Chim. Acts', 27 : 31 36. Newell, G. E. (Iqsq) Pollution and the abundance ol animals in estuaries. In: 'The Effects of Pollution on Lwmg MaterraJ (edit. by Yapp, W B.), 'Inst. Biol. Symp.', No. 8 ' 61 69. Newton, L. (1944) Pollution of the rwers of west Wales by lead and zinc mine effluent, 'Ann. AppI. Btol.', 31 .,I I1. Newton, L. (lqSq) Pollut,.m problems ¢~1' the river Rhe,dol, C,udiganshtre, "T'rans Bq~t. S ~ . Edmb. ', 3 8 ' 141 Ir~tl. Rees, C. B. (1939) The plankton ,n the upper reaches of the Bristol Channel, 'J. Mar. Biol. Assoc. UK', 23 : 3q7 425. Savage, P. D. V. (1965) Preliminary observations on the phytoplankton of Southampton Water, 'Brit. Phycol. Bull.', 2 : 515 516. Sn,.kland, J. D. H. and Parsons, T. R. (Iq65) A Manual of Sea Water Analysis, 'Bull. Fish. Res. Bd. Can.', 125 : 185. Sykes, J. B. and Boney, A . D . (1969) Some aspects of the phytoplankton ecology of Cardigan Bay, 'Brit. Phycol. j . ' , 4 .216. Wells, A. L. (1938) Some notes on the phytoplankton of the Thames Estuary. 'J. Anita. Ecol.', 7 : 105.124.

Monitoring Organo-chlorine Residues Concentrations of o r ~ o ¢hiorme pesticide residues are regudarly measured in a variety of wildlife specimens and m a wide range of foodstuJ'fs by laboratories in the United Kingdom. Marine a.nJmals fall into both of these categor,es, and as part of this wider programme the Fisheries Laboratories of the Ministry of Agriculture, Fisheries and Food and the Department of Agriculture and Fisheries for Scotland have examined samples of a wide variety of marine orgamsms for organo-chiorine pesticide residues during the past 7 years. The information gained from this work proved useful followfng the recent bird mortality along the west coast of Britain when high concentrations of organo-chlorine residues were found in the hvers of samples of dead birds. This therefore seems a suitable occasion to describe briefly what has been done by the Fisheries Laboratories and the way in which monitoring ,s expected to continue. Since 1965 the staff of the Ministry of Agriculture, Ftsheries and Food Laboratory at Burnham on Crouch has analysed many cUfferent species ol fish and shellf,sh collected from on shore sites and at sea around the coast of England and Wales. In January 1968, a routine monitoring system for organochiorine residues was started using samples of cod, whiting, plaice, mackerel and herr,ng. Most of the main fishing areas are sampled twice yeazly, between

January and March and June and August, respectively. In 19b3 the slaff ol the Department of AfT,culture and F'tshertes Freshwater Fishertes Labq~ratory at Pttluchry began to analyse a variety of samples of manne organisms including fish, shellfish, plankton, seals and porpoises. Since late 1968 part of this programme has been coordinated vwth that at Burnham on Crouch and organo chlorine residues have been monitored in the same species of fish thai are collected from the majm Scottish fishing porLs. Thus in the LIK fifteen ports are sampled twice yearly, so thai more than 150 fish samples are coUected each year. At each laboratory the samples of fish are analysed for organochlorine peshc,de residues by comparable methods in the muscle, liver and gonads, and s,nce the middle of 1969, analysts for the closely related polychiorinated biphenyls (PCBs) has been included as a routine procedme. In addihon to rouUne monitoring, samples of shellfish mussels in part,.'ular - from several local=ties are analysed at each laboratory on a twice yearly basis. Both laboratories also operate special pestle,de analysts investigations. For example, at Burnham on.Crouch these investigations include studies of seasonal variations in the concentration of residues in oysters and shrimps, surveys of particular areas and ecosystems and analysis of specurnens dying ,n the course of laboratory experiments to determine the toxictly 41