UThis paper not to be cited ,vi thout prior reference to tbe autbor"

International Co~~cil for

the Exploration of the Sea

C.H. '1983/ C : 14

Hydrocraphy Committee

TEE DISTRIBUTION OF UREA IN TEE BALTIC SEA

Jorge C. Valderrama

National Board of Fisheries

Institute of Hydrographic Research

F.O. Box 2566s - 403 17 Göteborg

SWEDEN

ABSTR.ACT

The vertical distr~bution of urea has been determined during

a five - yem: period (from Ju."le 1916 to lIay 1981) at 21 diffe-rent stations in the Ba1tic Sea on samples collected during

20 cruises. Results show pronounced seasonal variations with

the highest concentrations (up to 1.86 ~1) toward the end ofsp!ing, while thc lowcst (down to 0.10 p}I) were found during

winter ~~nths. A total ~!er3eC of 0.32 p}I was calculated. Ex-cept for same stations in the western Baltic Sea (Arkona ba-

sin, Hano bight and TIornholm deop) tho concentrations werenotably hiehcr above tho halocline than below it. Areas around

the Gulf of Finland and the Hauo bight show elevated averageCOllcentrations (0.48 end 0.36 jlU respectively) while the 10-west averae;e ware faund in ,thc contral purt of the Baltic i.e.

north of the Gotland deep (0.21 /~1).

SONHAIRE

La distribution vcrticale dc l'uree a et~ determine pendant

une periode da cinq ans (Juin 1976 a Hai 1981) dans 21 diffe-rentes stations dans 180 B~ltique sur des echantillons 'recuei-

11is dans 20 croisieres. Les resultats montrent des variations

saisonni~res tras distinctes, aveo les plus hautes concentrations(jusqu'a 1,86 ~l) vers la fin du printemps, alors qua les plus

funk-haasNeuer Stempel

•

basses (jusqu'a o,10fU1) ont 6t6 trouv6es durant les mois d'hi-

ver. Une moyenne totale da 0,32 pM a et6 calculee. Sauf dansquel(lUeS stations en 3altique occidentale (le bassin d' Arkona,

130 baie d'Hanö et le trou de Bornholm) les concentrations etaient

notablement plus hautes au-dessus de l'halocline qu'au dessous.

Certaines zones autour üu Golfe dc Finlande et de la baie d'lIanö

montrent une moycnnc plus e1evoe de concentrations (0,48 et 0.36}iM, respectivement) tandis qu~ les moycnnes les plus basses ont6te trouvees dans la partie centrale de la Baltique, c'est~a-dire

au nord du 1e troude Gotland (0,27 ~1).

INTRODUCTION

Urea (carbamid or carbonyldiamide), H2N- CO - NH2 ,is excreted into thc environment as an end product of nitrogen

metaholism by many higher organisms and as a product or micro-

binl action on amino acids, purines and pyrimidines.

A oonsiderable amount of urea found in some coas-

tal marine environments may be added by freshwater disoharges,

especially through Se\iage from densoly populated areas, since

man and other torrestrial vertebrates represcnt a primary souroe

of urea. In addition, drainage from aGricultural regions also

might contribute hea·.;ily if urea - based fertilizara are used

(Remsen et al. 1974).

Urea - docomposing bacteria have been shown to be

present in both fresh/rater und marine environments (Steinmann,

1976). 11arine phytoplankters have also been shown to utilizeurea as a source of nitrocen. Host cf these are inhabltants .of

estuaries or inshore areas (Carpenter, 1972), which auggestthaturea should be considered as an important part of the ni-

trogen reserve in coastal waters, especially where nitroQen is

the limitating factor, and during periods when nitrate levels

in the euphotic layer are minimal (Vac~aro, 196,).

During the two last decades, the distribution of

urea in eoastal and other oceanic watcrs has been studied. Ne-

well (1967) found concontrations as hiGh as 1.54 JÜ1 in surface'iaters of the ./'~'nGlish Channel; He Carthy (1972) reported 0.21

\ .

•

3.-

to 0.50 p}1 in waters off La Jo11a, California, and va1ues upto 0.,4 plI in surface waters along the Peruvian coast; Remsen(1971) found va1ucs from 0.27 to 2.50 p}I in surfacc watersoff the continenta1 she1fbetween Panam~ und Ca11ao, Peru, and

from 0.12 ru'I on the 1830 m depth 1ine between Cape Cod andCape May along the continental ahelf of the northeast Uni ted

States to high of 5.60 pli vithinNew York Harbor; Koroleft(1974) in a preliminary.study in Baltic waters reported va1uesfrom. 0.05 to 1.00 pl1, and more recently, S,teinmann (1976) re-ported levels for th: Kiel bight trom 0.01 to 4.52 pll. To date,there have been rather few measurenments of urea·in the Baltio

Sea•

The present report attcmpts to outline theresults

of a five - year study of urea levels at different stations in

thc Baltic Sea. For convenience, the area under investigation

has been divided into section A, from Arkona basin (BY 2) throughKarlsö deep (BY 38) to Landsort deep (BY 31), und section B,from Bornholm deep (BY 5) through Gotlund deep (BY 15) to theGulf of Finland (BY 23), as deocribed in figure 1. Some stationswere visited only few times. Por that reason they have been

grouped in order to get more representative values (BY 29/28,BY 27/26 and BY 25/24/23).

About 4000 oamples, from 21 stations, obt~inedduring thc coarse of 20 cruiscs carried out during differentseasons from Junc 1976 to l1ay 1981, were analyzed.

I'L\Tl::RIALS Alm HE'THons

Urea was determined by the spectrophotometric ce-

thod originally proposed by Newell ct ale (1967) and modifiedmainly by Koroleff (1976). It is based on the reaction withdiacetylmonoxime und semicarbazide in the presence of controlled

amounts of a weak oxidant in a stronsly acidio medium where

ohloride ions are included in excess to sensitize the reaotion.

Hanganous ions stabilize the resultant ma0enta coloured molecu-

lar complex and the presenoe of phosphate ions enables reasonable

reproduoibility to be achicved. Reaction takcs place under heatingat 10 oe. It is positive for compounds having the general formula

4.-

H1

- UR - CO - NIl - R2 , \-/here R1 1s hydroGen or a single aliphatioradioo.l md H2 not an o.oJ'l radioal. The reaotlon is quantitati-

ve for urea. Haximun abßorbanoe oeourtJ at 520 nn. i/hen a 5 omcell is used, oonoentrations from 0.10 to 10.0 rI1 of urea can

be measured. At the 2 p}1 level the relative standard deviationis :!: 2.6 %, \.,rhereas at the 0.2 rN level i t has been estimatedto be ±15%. ~ven if at tho Baltio Interealibration Workshopin Kiel (Maroh 1977), no statistioal treatment of the data weredone, the deviations from the true values were within the error

of the method (Grasshoff, 1977).

The common ions prosent in tho natural waters do

not interfere, nor are there interferences by ammonia, leuei-

ne, tyrosine, eystine, arginine, lysine, histidine, taurine or

urio acid. Thiourea and biurea react to some extent as do al-

lantoine and citrulline. Tbat mißht cause some problems in

water samples having a high ani~al produotion (RemGen, 1971),but all these compounds normally are not present in natural

waters in large enoush amounts to interfore with the method

(Koroleff, 1976). No interference from hydrogen sulphide inanoxio waters has been detected (Valderrama, 1979).

Thc sacples wero oollected directly from the

Hydro - Bios T?N' polycarbonate wo.tel' tJamplers together \'Ii th

samples for analysis of other nutrients, trom thc standard

depths generally used in the Baltic. Aliquots of 100 ml were

poured into glass bottlas und 0.5 ml of a saturated HgC12solution was used as preservative.The samples were analyzed

4 to 6 weeks after colleotion in 25 01 replicates. Preserva-

tion tests showed that ures saraples remain unal terable tor

at least two months aftor sampling using this procedure (Val-

derrama, 1979).

';li th eaoh series of samples replicates of blank.

and standard solutions at different concentrations (0.2, 0.5,1.0, and 2.0 fll) ware analyzed in order to calculate the

conoentration factor of reaeents, whioh for a 5 om cell should

be elose to 9.

5.-

RESULTS

Table I gives maan valuas of the vertical profile

concent~ation of urea determined during each of the 20 cruises

showing results for sections A and B, as for the total studied

area (T). At the left of each colucn values in the w~ter masses

above (upper fiGUre) and bclow (lower figure) the 'nalocline,

and at the right the total mean values for the all area are

shown. Values are plo~ted in figures 2 and 3. Except for thecruise on June 1916 all measurenmants show higher levels ofconcentration above than below the halocline.

From the Table I and figares 2 and 3 a pronoun-ced seasonal variation of the concentration can be observed.

The highest values were determined during Hay and June und

they may reach up to 0.49 pM (on an average) but some isolatedvalues may reach up to 1.86 pli. Thc lowest levels were determi-ned in January and on an average they may reachdown'to 0.11~I with some isolated values'down to 0.10 pM.

\lhen a eraph with the values obtained during all

the different cruises"is plotted for a "representative" year

the figure 4 i8 obtained. During sprinc and early summer urealevels reach a maximun which decreases laterduring autumn and

winter with two smaller ma.-x:imums during late summer und autumn -

early winter (respectivaly Septembor and November - December).

Tables Ir and IrI and fi~~es 5 and 6 give a pic-ture of the seasonal variation and distribution of the concen-

tration above and below the halooline for the different stations

included in the two sections. ,The Hanö bight (station HE in the

seotlon A) und the Gulfof Finland (Stations BY 25/24/23, in the

section B) were the areas having the highest levels of oonoen-

tration,whioh 1s especially outstanding during spring months,

respeotively 0.55 and 0.60 ~1. In the Gulf of Finland these

hieh'levels were observed even during all other periode. Sta-tions as liorköping deep (BY 32),Fär~ deep (BY 20) and Ryss-

hälan (BY 8) presented the lowest avcra&c concentrations evenduring spring.

6.-

Figure 7 show the average concentrations foundduring the entire investigated period for each station indica-

ting values above and bclow the halocline. The concentration

average of all saoples (seotion A 0.32 ~1 and section B 0.31"pM) even as for thc levels above and below thc halocline(seotion A respeotively 0.54 and 0.29 p11 and section B respeo-

. tively 0.35 and 0.27 plI). A total average of 0.32 pl1 for theentire investigated area was caloulated, 0.35 and 0.28 ~1 forreopeotively above and below tho halocline.

Figure 8 sbows tbo intocratcd valucs of concen-

tration levels ror the two sections during the tour seasonal

periods, they are nearly similar for both soctions.

Except for stations DY 2 (during spring, summer

and autumn) , HB (during spring and Sumr::ler) , BY 39 (durinaspring), and BY 5 (during spring) all other stations exhibitthc highcst conoentrations abovo thc haloclinc (Tablcs II and

I1I, and tigures 6 and 7). Thc ncntioned stations are looatedin the south - western part, that io near the only communica-

tions (through the Belts and Örcsund) that tbe Baltic Sea has

with thc rest of tbc world ooean, and whcre the halocline is.

more pronounced, and where heavy aalt water from thc Kattegattflows eastcrly as a botton current below thc outtlowing brackish

surfaoe water.

Thc diffcrences in concentration levels of urea

between the two water layers separatcd by thc halocline are

higher toward thc eastern areas of thc Baltic, espcoially du-

ring spring and summer. These differcncea may reacbup to 77%in the station BY 27/26 during spring and 78% in tbe station

BY 29/28 during summer (Table III and figure 6).

Figurea 9 and 10 show the concentration isople-tes in a vertical profile for respeotively section A and sec-

tion B during a typical spring period. The halocline level ioindioated with a segmented line.

Tbc results obtained during the investigatedperiod suggest that tbc high urea levels measured above tbe

halocline and especially during spring and, to some extent,

during autumn months, are connected with the primary produc-

tion, and in areas such as thc Gulf of Finlnnd and the Hanö

bight even "li th freshwater discharces from the surrounding

densely populated areas. It is more difficult to explain why

th1s pattern is inverted in thc oouth - western part of the

Baltic~ As a proliminary expl~~ation it may be assumed that

it 1s connected with inputn arisine trom Öresund which repre-

sents another high populated area.

In the Baltic, nutrients such as nitrate. nitri-

te and ammonium build up durine the winter months and in the

euphotie zone they are eonsumed during a few weeks in spring.

An intensive primary produetion thon oeeurs and thc system

beeomes nitrOGen limited during thc end of spring and summer

(Rönner, 1983). Therefore, urea muy be eonsidered an impor-

tant nitrogen reserve souree in the Baltie Seu.

REFERENCES

Carpenter,E.J., C.C. Romsen, and S.i;I. Watson (1972). "Utiliza-

tion of urea by somo marine phytoplankters". Limnolosy

and Oeeanography, 17 (1972) 265 - 269.

Grasshoft, K. (1977). Report of the Baltic In~ercalibration

\/orkshop, pp. 88. Interim Commission for the Proteetion

of the Environment of the Baltic Sea.

Koroleff,F. (1974). "On the determination of urea in sea water

and some preliminary data from the Baltic". 9th Conferen-

ce of thc Ba~. tic Oceanographers. Paper No. 25 a. 1974.

Koroleff, F. (1976). "Determination of urea". In: K. Grasshoff

(Editor). Methods of Seawater Analysis. Verlag Chemie,

\'leinheitt, pp. 145 - 149.

1-1cCarthy, J .J. and D. Ka:nykowski (1972). "Urea and other nitro-

genous nutrients in La Jolla Bay during February, March,

and April 1970". Fishery Bulletin, 70 (1972) 4 1261 - 1274.

Hewell, B.S. (1967). llThe determination of ammonia in seawater".

J. I1ar. Biol. ass. U.K. 27 (1967) 271 - 280.

8.-

Newe1l, B.S., B. Morgan, and J. Cundy (1961). "The determinationof urea in seawater". 'J.ofl'Iar. Res. 25 (1961) 201-202.

Remsen, 0.0. (1911). "The distribution of urea in coasta1 andoceanicwaters". Limno1ogy and Oceanography, 16 (1911)

132-740.

Remsen, 0.0., E.J. Carpenter, and B.W. Schroeder (1914). "The ro-1e of urea in marine microbia1 ecology". In: Effect of the

ocean environment on microbial activities, pp. 286 - 304.2nd. US - Japan Oonf. of Marine microbio1ogy. Edi ted by R.

Oolwell and R.Y.l1ori. University Park Press. Baltimore. USA.

Rönner, U. (1983). "Bio1ogical nitrogen transformations in mari-ne ecosystems with emphasis on denitrification". Disserta-

tion. Dept. of Harine Microbiology. University of Gothem-

burg. 45 pp.

Steinmann, J. (1916). "Untersuchungen über der bakteriellen Ab-bau von Harnstoff und Harnsäure in der westlichen Ostsee".

Botanica Harina, 19 (1916) 41- 58.

V~ccarotR.F. (1963). "Available nitrogen and phosphorus and thebiochemical cycle in the Atlantic off New England. J. of

Har. Res. 21 (1963) 284 - 301.

Valderrama., J. (1979). "Ureahalten i Östersjön". Svenska. Havs-

forskningsföreningen. Meddelande Nr. 14, pp. 54 - 65.

• •60'

!B.I

20·

]3[ .- 7 55·J

'!l•I".

12'

,PiL;ure 1.- ~a:lplinc o't.1.tions

(ot

10.-

'AlL! 1.- Average conoentrations of urea (in ~1) dur1ne 20 oruieesto the Baltio Sea, pointing out the levels above an4

below the halocline.

Cru1se Seotion A Seotion B TOTAL ('1')

1'76.06.16 - 06.230.41

0.420.45

0.430.44

0.430.42 0.40 0.41

0.31 0.32 0.3208.24 - 09.08

0.240.28

0.240.28

0.240.28

11.22 -12.040.33

0.320-30

0.300.31

0.32 0.30 0.310.31

1977.06.01 - 06.140.44

0.410.40

0.360.42

0.380.35 0.30 0.32

08.30 - 09.200.32

0.310 • .37

0.330.34

0.320.30 0.28 0.30

11.22 - 12.030.40

0.360.32

0.300.36

0.330.30 0.29 0.29

0.28 0.27 0.281978.01 •24 - 01 .31

0.23O.2~

0.200.24

0.210.24

03.18 - 03.290.41

0.400.44

0.400.42

0.400.38 0.31 0.38

05.17 - 06.010.49

0.450.47

0.390.48

0.420.31 0.29 0.32

08.22 - 09.060.27

0.260.39

0.320.34

0.300.25 0.25 0.25

11.14-11.230.32

0.310.34

0.320.33

0.310.31 0.29 0.30

1979.01.16 - 01.190.31

0.280.34

0.310.33

0.300.22 0.26 0.25

05.29 - 06.160.39

0.360.39

0.340.38

0.350.33 0.30 0.31

08.21-08.240.27

0.260.27

0.240.27

0.250.23 0.19 0.21

11.06-11.280.28

0.270.27 0.28

0.24 0.250.27 0.20 0.23

,----------- ----- --- ---------

11 .-

TABLE I (cont.).-

Section A Section B TOTAL (T)

0.27 0.20 0.231980.01.15 -01.22 0.24 0.19 0.21

0.20 0.17 0.18

05.28 - 06.130.46

0.440.48

0.420.47

0.430.40 0.34 0.36

0.24 0.22 0.2310.27 - 11 .13 - 0.22 0.21 0.22

0.20 0.20 0.20

0.25 0.21 0.23• 1981.03.10 - 03.13 0.24 0.20 0.220.22 0.18 0.2005.12 - 05.31

0.380.38

0.360.35

0.370.36

0.37 0.34 0.35

TOTAL 0.34 0.35 0.35AVERAGE 0.29

0.320.27

0.310.28

0.32

Figure 2.- Average concentrations of urea measured during 20 cruises to the 8altic Sea pointing out

the levels above (~) and below (~-~) the halocline. Section A.

Jl4 urea

0.50

0.40\\\

. 0.30\\\ I}f

0.20

0.10

o

1976 1977

•

1978 1979

•

1980 1981-"I\).I

f'1 urea0.50

0.40

0.30

0.20

0.10

o

~\\\\\\ Iif

•

~, \I \

--4 I ~ A ,..A........~ ..)\ I .... /' ,. \

\ I ''t:I)y \\ I \.}i \

•

-I

1976 1977 1978 1979 1980J

1981

Figure 3.- Average concentr~tions of urea measured during 20 cruises to the Baltic Sea pointing out

the levels above (0---0) and below (la- - -A) the haIoeHne. Section B.

~

\).I

•I

0.20

DosAJJAJ

J.'i[,"Ure 4.- J~

•TABLE 11 .- Seasonal distribution of the concentrations of urea above and below the halocline.

Nean values, in ft. Seotion A.I·

depth number of Jan Feb Har Apr I1ay Jun Jul Aug Sep Oct Nov DeoStation TOTAL

m samples Winter Spring Summer Autumn

1680.32 0.32 0.30 0.26 0.30

BY 2 48 0.30 0.38 0.31 0.30 0.320.27 0.50 0.31 0.38 0.36

0.26 0.54 0.28 0.34 0.36Hanö bieht 82 205

0.240.25

0.570.55

0.360.31

0.300.32

0.370.36

0.270.26

0.38 0.34 0.28 0.32BY 39 50 128 0.39 0.32 0.28 0.32

0.23 0.40 0.26 0.22 0.31

0.30 0.41 0.32 0.34 0.35Segerstad 1 72 148 0.29 0.40 0.30 0.33 0.34

0.21 0.38 0.25 0.32 0.32

0.32 0.45 0.28 0.260.31 0.36

BY 38 112 272 0.29 0.44 0.30 0.330.25 0.40 0.23 0.28 0.29

0.31 0.480.43

0.270.23

0.330.30

0.370.33BY 34 105 223 0.30

0.27 0.33 0.19 0.27 0.27

1960.26 0.40 0.26 0.32 0.33 0.29BY 32 205 0.23 0.34 0.23 0.31 0.260.21 0.29 0.20 0.29

0.31 0.400.36

0.30 0.280.26

0.33BY 31 459 389 0.26

0.280.26

0.270.24 0.27

0.300.33

~

TOTAL 0.30 0.43 0.29 0.30 0.34 \.111729 0.28 0.40 0.28 0.29 0.32

•Sect10n A 0.25 0.37 0.26 0.28 0.29

I

TABLE III.- Seasonal distribution of the oonoentration of urea above and below the halocline.

Mean values, in ~1. Section 13.

depth number of Jan Feb 11ar Apr Nay Jun Jul Aug Sept Oct Nov DeoStation TOTALm sampIes iYinter Spring Summer Autumn

BY 5 91 2330.24

0.220.32

0.340.37 0.24- 0.30

0.36 0.34 0.24 0.290.20 0.28 0.24 0.28

0.29 0.32 0.35 0.26 0.31BY 7 83 1920.28

0.290.30

0.310.32

0.34·0.26

0.26 0.300.30

0.26 0.35 0.290.26

0.24 0.30BY 8 109 132 0.25 0.34 0.23 0.290.23 0.33 0.19 0.21 0.26

BY 9 2640.31

0.270.39

0.360.32 0.22 0.32127 0.29 0.22 0.290.22 0.31 0.25 0.21 0.25

0.290.26

0.43 0.38 0.30 0.36BY 15 249 350 0.3} 0.31 0.28 0.310.24 0.30 0.24 0.27 0.27

3060.30

0.260.36 0.27 0.28 0.31BY 20 203 0.32 0.23 0.25 0.270.23 0.27 0.19 0.23 0.23

BY 29/28 170/200 260/320.31 0.39

0.360.32 0.31 0.35

0.27 0.250.26

0.28 0.310.23 0.32 0.18 0.27

BY 27/26 176/113 274/240.25

0.240.55 0.29

0.230.32 0.39

0.230.44

0.170.30

0.260.33

0.31 0.27

BY 25/24/23 73/73/60 87/27/200.28

0.270.68

0.600.40 0.37

0.360.51

0.48-..0.38 0\0.25 0.47 0.30 0.33 0.42 ..I

TOTAL 0.28 0.42 0.34 0.29 0.35Section 13 2174 0.23

0.260.32

0.380.23

0.290.25 0.27 0.27 0.31

17.-

J-M urea Jrm Fcb l"tur

0.30 m: f;·~'t7;j lnl rn.r, t~ -,.1 PI"l t:\ ! "0.20 J, 11~1 h1

11-':\1 ~~~l

~".;~~ !t'~ f0.10 ~-., JI.:V I 1"h"'l l' ;~ ,'If.:., ,taJ .,.. / jllt:i ~~~f0 lli '-l..:J0.60

0.50

0.40

0.30

0.20

0.10

o

Apr Huy Jun

0.40

0.30

0.20

0.10

o

Jul Aug Scp

Oet Nov Dee

®l ~'iJ ( ~~. ~-, '''' ..~fl ~\ l" l;.:1 JJ r";~ t~, ~}'1... 1-{~~f. ,~ ~~ t·{i !")J s~";'~ .~~~ r, i".'

2 HB 39 S1 38 34 32 31 TOTAL

o

0.20

0.40

0.10

0.30

figure 5.- Seasonal vorintiono of the average concentration of urea

on secHon Astations (Junc 1976 - f4ay 1981), above ( • )and below ( tJ ) the hnlocline.

18.-

t' urea0.30

0.20

0.10

o

Jan feb Mnr

Apr f.lny Jun0.60

0.50

0.40

0.30

0.20

0.10

o

Jul Aug Sep0.40

0.30

0.20

0.10

o

20 29/28 27/26 25/24/23 TOTAL15

Oct Nov Dec

98o

BV 5

0.30

0.20

0.10

Figure 6.- Seasonal variations of the average concentration of urea

on section B stations (June 1976 - Hay 1981), above ( IB )

nnd below ( tJ ) the hnlocline.

19.-

pl-1 urea

0.40

0.30

0.20

0.10

oBY 2 HB 39 S 1 38 34 32 31 TOTAL A

0.50

0.40

0.30

0.20

0.10

oSY 5 7 8 9 15 20 29/28 27/26 2'124/23 TOTAL B

Figure 7.- Average concentration of urea in different stations of the

Baltic Sen from June 1976 to Mny 1981, Above ( GI ) andbeIm" ( 0 ) the halocline.

.~;,,~

~~

·li

l-1

A B A BBA

":"J r

20.-

SV 2 Hb 39 S1 38 34 32 31

Figure 9.- Concentration of urea Crt1)Seetion A

Spring (1978.05.17 - 06.01)

(-----) halocline

100 km

400

450

300

200

150

O---,~"--------:,-----~-.c;:--"",,,,="""--:::-:---

20depth

m 40

60

80

100

(- - - --) halocline

Figure 10.- Concentration ef urea (~1)

Sectien B

Spring (1978.05.17 - 06.01)

SV 5to

20depth

m 4060

80

100

150

200

250

7'f

100 km

8 9t t

15 20, t

29 28 27 26t

-c • • ...