Polychaeta in the estuary of the Piauí Ri ver, Sergipe, Brazil

1\:Jaria A. SANTOS, C.S.G. SANTOS & C.M.M. OLIVEIRA

Departamento de Biologia Campus Universitário

49000 Aracaju. Sergipe. Brasil

ABSTRACT

58

The distribution of infaunal polychactcs was exarnincd in order to discrintinate polychaete Ob5.embla:.e' in tbe estuary. In ~larch 1987. 4.398 specimens were collccted in 123 samples from 15 arcas. A clustcr and ordinauon :m:l!)'u \\:b used to define benlhic polychaete assemblage~. Two associat10ns were present wbicb were related to lhe hl!b and low encrgy depositmnaJ environments and hydrological gradients. The first group. restricted to Lhe upper n-a..-be of lbe e-tuiJ.l) was composed of Laeonereis acwa. Amplticreis gunneri, Hereromasws similis, Neanrh~s wccinca aDd Scoldtpu uxana The econd group. prcscnt in the middle section o f lhe estuary. was dominated by Prionospio (P.) c[ tlub1a. Scoloplos ~p ..

Euclymene sp .. f solda pu/citei/a and Magelona papillicomis.

RÉSUMÉ

Polychctes de l'cstuaire de la rivicrc Piauí, Sergipe, Brésil

Cette étude porte sur la distribution de la faune des Polychetes de l'estuaire du fieuve Pt:wí. - 3 spéctmet:S f~ récolt& en mru·s 1987. cn 123 échantillons de 15 régions. L'analyse en composante:. pnnc1pa!e et b ~ himtr.nique permettent de définir les assemblages des Polychetes benthiques. Deu'{ groupe, ont éte tdeotifi k p;-emxr es1 ~lia partie amont de l'estuaire du Piauí: il est formé de Laeonu~is oc..u.ta.Amplúcuis f!~ri. HncromtUI rimilis ·~Cl111MS.

succinea et Scoll'iepis texana . Le deuxieme groupe esL prêsent dan> la p:u'tie mo)e~ de r~5te3Jre. 2 I!S es~ce­

dominantcs Prionospio ( P.) c f. dubia. Scoloplos sp .. EudymL"ne P- /solda pwchrlla etMa~ :a rzpwiCL'.nus

JNTRODüCTTO~

The estuary of lhe Piauí Ri ver is located in L11c !>late of Sergipe. Brazil A qualltaU\e 'ludy of polycha l.es was made off-shore (No ATO & L UNA, 1970 a. b) and in lhe Sergipe River Estuai) (SAXTOS. 1919) which pro,·ided information on lhe distribution of polychaetes and olher animal . Swdie were made in lhe Piauí-Fundo-Real syslcm to characterize l.bc region. according to physicochemical variations (AlVES. 19 9). zooplankton {AR.!\ JO. 1989), sediment and Foraminifera distribulion (ZL'CON, 1989) and phytoplankton (FRA.'\CO. 199 1) Macrobenlbjc

SAl'<TOS. M./\ .. SAJ''TOS . C.S.G. & C.M.M. OUVEIRA, 1994.- Polychaeta inthe estuary of the Piauí Ri ver Sergipe. Drntil. In: .1.-C. OAUVI:--.1. L. LAUBIER & D.J . REISH (Eds). Actes de la 4cmc Conférence internationale des Polychete:;. Mém. Mus. narn. Hisr. nar .. 162 · 541 -547. Pari~ ISDN 2·85653·214-4

542 M.A. SANTOS. C.S.G. SANTOS & C.M.M. OLIVEIRA

fauna studies in o t11er estuarine regions of tbe Brazilian Coasl bave been made by B EMV ENUT (1987), LANA (1986) and LANA er al. (1989). The objective of !bis paper is to describe the distribution and diversity of sublidaJ polychaetes in a tropical estuary located in nort11east Brazil.

STUDY AREA

The Piauí Ri ver is pari of tbe estuarine complex, located in Sergipe, Brazil (11°22'30" SI 32°22'33" W) (Fig. 1) . It is approximately 40 lan long and 50-5,000 m in widlb. The deplll ranges from 1-27m (FRANCO, 1991). Tbe waler lemperature ranged from 24 to 29.5 °C in 1986/87 (ALVES, 1989). The region is characterized by dry and wel periods. Tbe rainfall range from 241.5 mm/mont11 in July to 46.1 mm/month in December (ALVES, 1989). The sediment of tbe Piauí Ri ver varies from coarse sand poorly selecled in tlle upper estuary to fine sand well selected al t11e moutb. The tota l granulometrical distribution bas a median value o f 2.5 (± 1.1 ) and varies from coa..rse sand to clay. The highe t percentage of fine sand was 43.6 (Zucor-:, 1989). T he selecúon varies from 1.16 % well selecled sediment to 53. 18 poorly elected sediment. Tbe area..s 7 10 lO (Fig. 1) are characterized by biodetritus.

The salini ty varies as a result of seasonaJ llucruations of rainfall, river run-off, and tidal amplitude (FRANCO, 1991). These waler can be divided into lbree categories: 1) limnelic water from ri ver ftow in tlle upper pa..n of t11e estuary, 2) mixollaline waters from tlle mixture of ri ver and coa..stal water and 3) mixoeuhaline waters at llle moutb of the river (ALVES, 1989).

STA LUZII\ 00 ITANH I

I I I

I

I I

I

' ' \ 1

I , , ,

I I

N

i

Z . IOO 0 t 100 4. J OO •

FJG. t - Pia ui Ri ver. showing the posilion o f the samplings areas.

Dissolved oxygen generally ranged from 2.2 10 6.8 mg. 1-1 (ALVES, 1989). Tbe median esluarine region llowed the higllest levei of nutrienl . dialom density and zooplankton (ALVES. 1989: FRANCO, 1991: ARAUJO,

1989). Tbe cbange in nutrients are probably a consequence of the annual climawlogical and hydrographical pattem.

niE E:STI;ARY OF 11-IE PlAUÍ RIVER, SERGIPE. BRAZIL 543

~L\ TERIAL ANO METHODS

- . Ftfteen areas were sampled aloug 35 krn o f tbe estuary (Fig. I ). A total o f • : a lO liter Van Veen grab. Three stations were sampled in each area, aud four

eadl stlúon. one for sediment analysis a:nd tbree for biological analysis. Only two stations ~ • .: - J:. Eacb biological sarnple was washed tbrough a 0.5 mm sieve. Larger animals were

e Remaining material was stained with Bengal Rose and fixed in formalin. Samples were I;TA!Ihf.~ 10 - cr :dcobol prior Lo identification. Environmental pararneters and olher biological aspects of the

-~ \\ ere rudied concurrenlly (ALVES, 1989; ARAUJO, 1989; FONTES, 1989: Z UCON, 1989 ; n.

ere ranked according to occurrence, abundance ar1d percentage of to tal number of specimens. Slt:m:r:OI-Wiener di ver ity index ar1d evenness índices were used (GRA Y, 198 1). A matrix data will1 t11e

.....,...._.....,_..LC oi specie and 41 sarnples was used for U1e data ar1alysis. The replicates were summed up by area lf« aud ordination analysis. Tbe variables indicaling abundance were logarithmically trar1sformed using lhe apre:ssioo Y,1 = log (xij + 1) (~EE 1, 1979).

Tbe rnatrix was ubjected to a cluster analysis (WPGMA), employing lhe Czekanowsld Coefriciem of si.m.i.larny. The multivariate similarity pattem s were ai o studied witb a Q-mode Principal Component Analysis llCA). Tbe analysis in Q mode wa done because of tbe large number of spccies. A cornputer prograrn ACOMP wriuen by J. L. V ALENllN (lEAPM - MM) was used.

RESULTS

A total of 4.398 speci.mens wa collected which belonged to 81 taxa in 32 families. Tbc dominant taxa were identified by occunence and abundance. The mo L abundam species were Prionospio (P.) cf. dubia , Laeonereis acura, Euclymene sp. and I solda pulchella (Table 1 ). The diversity rar1ged from 0.01 to 2.8 and was higher from areas 2 to 10. 111e lowest val ue was found at areas 11 to 15 (Table 2).

SIMILARIT V

3

6

4

7

8

lO

9

li

6

12

14

FIG 2. - Deodrogram for 80 species of polychactes. cons idering 15 areas. Tbe abundance of lhe species was summed up in eadJ a:rea.

O~~Mer analy is indicated: I) Area I aL lhe moutll of tbe ri ver is eul1aline and is separated from t11c oU1crs. The sa.linity W4b about 35.0 %o, and U1e sedi.ment was principally well sorted fine sand. 2) Areas 2 to 11 were clustered ~ ~ lbe.r ~;l.h two group : areas 2, 3, 5 and 4, 7, 8. 9, 10, 11. The salinity ranged from 18-30, P.S.U. and Lhe

544 M.A. SANTOS, C.S.G. SANTOS & C.M.M. OLN EIRA

T ABLE 1. - Rank and abundance of the most common polycbaetes taxas collecte.d in tbe Piauí Ri ver, Sergipe .

Species Rank Occurrence Numbers for survey % o f total (no) (f o tal)

Scoloplos sp. l 51 207 4.70 Prionospio (P.) cf dubia 2 45 I 593 13.48 /solda pulchella 3 36 I 352 8.00 Tharyx sp. 4 35 I 63 1.43' Ceratocepha/)" crosslandi 5 35 I 13-J 3.04 Euclymene sp. 6 r I 447 10.16 Poecilochaetus australis 7 26 I l73 3.93 Goniada maculata 8 I 23 I 47 1.00 Ma~telona papillicom is 9 I 23 I 278 6.32 Laeonereis acuta 10 I !3 I I 168 26.55 Si~ambra ~ru/iii' <r' 11 I - -. I 32 0.72 -Polvcirrus cfplumos11S 12 I : t I 74 1.68 M a~elona nona lo i 13 I 18 I 29 0.65 Neantlles succinea p _! 16 I 43 0.24 Stauronereis rudolphi·senso I 15 I 16 I 24 0.54 Cabira cf. incerra I 16 I 15 I 35 0.79 Trochochaera sp. I r- I .5 I 156 3.54 Diovatra A I IS I 15 I 41 0.93 DiopaJra B I 19 I ·-.~ I 22 0.50 Glycem sp. A I 20 I n I 14 0.31 Pista corriemi.s I 21 I 12 I 15 0.34 Magelona mriolamellaia I 21 I 12 I 33 0.75 Pectinaria caJharinensis I 23 I l2 I 13 0.29 Stemaspis capillata I 24 I li I 24 0.54 Malacoceros m nderhorsti I 25 I ll I 17 0.38 Parandalia tricuspis 26 I lO I 22 0.50 Amphicteis ~tunneri 27 10 j 26 0.59 Pectinaria catlwrinensis 28 lO 13 0.29 Mmphysa sp. 29 lO 10 0.22 Kinber~onuphis spp. 30 10 lO 0.22 Scolelepis sp, 31 9 15 0.34 Hemipodus B 32 9 24 0.54 Glvcera americana 33 8 10 0.22 Glyci1ule mulridens 34 8 9 0.20 Ma~elona posrd'/llonxma 35 6 6 0.13 Laonice sp. 36 6 8 0.18 Heteromasrus similis 37 6 9 0.20 Owenia fusif'onnis 38 6 8 0.18 Cllone sp. 39 5 12 0.27 Spiophanes sp. 40 4 30 0.68 Loimia medusae 4 1 4 5 0. 11 Eunoe sp. 42 4 7 0.15 L:rsidice sp . 43 4 7 0.15 Branclliomma ni"romaculara 44 3 7 0.1 5 Pecrinaria Iael ia 45 3 3 0.06 Srhenolepis ~trubei 46 3 5 0. 11 O thers 50 - 118 2.68 TOTAL 4.398

POL YCHI\ETA IN THE ESTUI\R Y OF THE PIAUÍ RI VER. SERGIPE. ORAZfL 545

sediment rcmged from and to ilt and clay and was charactelized for biodetri tus in areas 7 to 11. 3) A reas 12 to 15 were character ized by salini ty ranging from 1 lo 15 P.S.U., going from mesobaline LO o ligobaline zones. Tbe sediment was mostly coarse sa.nd.

TABLE 2.- Diver i ly and evenness values

Arcas Diversity Evenness Areas Diversity Evcnness

I 2.14395 0.97575 9 2.46250 0.70427

2 2.67771 0.85400 lO 2.16672 0.60005

3 2.44909 0.700+4 l i 2.47467 0.84045

4 2.88888 0.75890 12 1.04351 0.75274

5 2.00215 0.66833 13 0.66225 0.4777 1

ií 2.52725 0.75843 14 0.24756 0.17858

7 2.39059 0.63959 15 0.01851 0.02670

8 2.1 8262 0.60002 TOTAL 2.79627 0.63812

These group o f areas. clustered together, were part ially int1uenced by changes in polycbaete densily. However, U1ese rcsults divided t11c Piauí Ri ver in 3 regions: U1e mouth, area I . tl1e lower estuary, area 2 to 11 and lhe upper estuary. area 12 to 15.

K (ILt ... )

)-IIIJ.O .. I lt ( II,Z "'t.)

' .. "

.. I>

;l . !::

• 0.0

~

_J c QD.

~ I

~ ----u~------'

.t-r<a/

~L ~/ , -o.•

.... • • :•B

•

• •

~

QD

I

•" ••

10

•

~INCWAL COMPONENT I ( l1,6 "f.)

• 1.0

Fro. 3. - Position o f 15 arcas on plincipa l componcnts: lefl. I. li and In: righl. I and rv showing principally arca I .

By projecting tbe cores in lhe orthogonal space of tbc f ir 1 lhree principal compooent (Fig. 3A), i t was possible to see 1hat groups of stalions wcre perfectly discriminated. The fu·sl axis wa related to U1e abundance of Prionospio ( P.) cf. du bia, Scoloplos sp., Euclymene sp., ! solda pulchella and Cerarocep!Jala crosslandi, indicating lhe mo L similar areas from 2 to 11 divided into two groups: 2 LO 5 aod 7 10 11. Tbe econd axis was

546 M.A. SANTOS. C.S.G. SANTOS & C.M.M. OU VEJRA

relaLed to the abundance of Laeonereis acuta , Amphicleis gunneri, Scolelepis texana, Hemipodus sp. in area 12 to J 5. The fourlh axis was probably related Lo the negaLive abundance of species (Fig. 38 ). AJmost U1e same groups were obtained by cluster analysi : area l isolaLed, areas from 2 to 11 clusLered LOgeLher and areas 12 to 15 cJustered togelher (Fig. 2).

DISCUSSION

Tropical estuaries are influenced by lhe seasonal rain pattem and tbe resulting effects due to sedimenlation, erosion, dissolved oxygen and nutrients. Nearly ali lhe benthic su.rveys of tropical esLuaries have been taken along U1e casL and west coast of lndia, (ALONGI, 1990). The mo L extensi ve investigations of subtropical estuarine macrobenthos were near Brisbane in Queensland, Australia (STEPHENSON et al., 1972; STEPHE SON et al., 1977). STEPHENSON et a/. (1972) stated that workers in lhe subtropics and tropics failed to find communities w iU1 only a few dominant species.

MAURER & VARGAS (1984) found a depauperated infauna in lhe soft bollom benU1os in lhe Gulf of Nicoya, Costa Rica. They concluded thal tropical estuarine corrununities were gcnerally low in density and biomass. The mean Shannon-Wiener diversi ty for polychaetes was of 1.91, range= O to 3.09 (MAURER er al. 1988).

In lhe Piauí River the diversity was similar to the values found in Costa Rica (M AURERet al, 1988). The influence of industrial wastes in the Piauf Ri ver estua.ry could be considered as a factor causing lhe Iow diversity. Comparison of lhe polychaetes obtained in lhe Piauí River estuary and lhe Sergipe estuary in ilie nortbeastern region of Brazil (SANTOS, 1979) showed lhe ame pauem of species composition and species abundance.

Zones of changes occuned in Lhe Piauí River, and it was possible to divide lhe ri ver in three region, U1e mouth, lhe lower c tuary and the upper estuary. Similar regions were found in formniniferan sLudies of Piauí River (Zuco , 1989) and macrobentllic studies of Sergipe River (SANTOS, 1979).

The upper part of U1e Piauí Estuary, areas 12to 15. was dominated by L. acwa andA. gunneri. The occurrence of L. acuto as dominant species, in the upper ri ver. was observed in Sergipe Estuary (SANTOS, 1979). The occurrence of L. acuta and H. similis association in tlle upper river was also observed in thc soulheastern coast of Brazil (LANA. 1986: BE~1VENUTI , 1987). The e pecie. are eu.ryhaline wilh reduced rnobility.

In t11e lower estuary areas 2 to 11 with mixobaline waters, t11e grea1est abundance of polychaetes, plankLon and nutrients were present (ALVES, 1989; FRA co, 1991). This suggested lhat lhe benlhic population distribution was influenced not only by salinity and sediment but also for nutrients and productivity (ALONGI, 1990). The occurrence of Prionospio (P.) cf. dubia, Scoloplos sp., Euclymene sp., !solda pulchella and Cerawcephala crosslandi association was also found in Sergipe Estuary (SA TOS, 1979).

Area l was located at lhe moulh of tbe estuary, in a region of continuous sedimentation, and was separated from lhe olhers by cluster and PC analysis.

The pauem of distribution of the polychaetes in Ule Piauí Ri ver are directly influenced by the pbysicochcmical gradiems, sedimem 1ypes and by topography. IL is possiblc 10 notice groups of dominam species in each one of t11e three region , and t11e decrease of Ule diversity from U1e moutll lo U1e head of t11e estuary.

ACKNOWLEDGEMENTS

We are gratefulto M Se C. R. P. Franco for critical ly reading Ule manuscript, to Dr. Paulo da C. LA A for help us in polychaetc identification and A. F. Diniz for ordenation analysis. Tbi study was supported through grant from lhe lmennini L.ry Comrnission for Marine Re ources.

REFERENCES

ALVES. J. P. H .. 1989. - Projeto integrado para avaliação da potencialidade do estuário dos rios Piau í-Fundo -Real: Vol. ll . Características físico-químicas da água e comportamento dos nuu·ientes. Repor/. Aracaju/SE. UFS. 43p.

ALOI'GI. D. M .. 1990. - The ecology of tropical soft-bottom benlhic ecosystems. Oceanogr. mar. Biol. Ann. Rev .. 28 : 381 -496.

ARAUJO, H. M. P .. 1989. - Projeto iutegrado para avaliação da potencialidade do estuário dos rios Piauí-Fuudo-Real: V oi. lll . Biomassa do zooplancton. Report, Aracaju/SE. UFS. 130 pp. ·

POLYCHAETA IN T HE ESTUARY OF THE PIAUÍ RI VER. SERGIPE. BRAZIL 547

BEMVEN1.JI1. C. E., 1987. - Macrofauna bentônica da região cstuarial da Lagoa dos Patos, RS , Brasil - Simpósio sobre ecossistemas da costa sul e sudeste brasileira. Publ. ACIESP. 54 : 428-459.

FONTES . A. L.. 1989.- Projeto integrado para avaliação da potencialidade do estuário dos rios Piauí-Fundo-Real: Vol. I. Caracterização geomorfológica da bacia do Mangue Seco (Piaui-Fundo-Real). Repon. Aracaju/SE. UFS, 22 pp.

FRAI'>CO, C. R. P., 1991. - Plancton diatOIIIS of rhe Piem( ri ver eswary (Brazil): seasonal disrriburion and biogeographic affinities. Master Thesis, Un iversity of Rhode lsland. IGngston. 169 pp.

GRAY. J. S .. 1981 .- Tl!e ecology ofmarine sediments. Cambridge University Press . London. 185 pp.

GREEN. R. I-1.. 1979. - Sampling design and stalis tical methods for environmenta l bio logists. John Wilcy & Sons. New York. 257 pp.

LANA. P. C., 1986. - Macrofauna bêntica de fundos sublitorais não consolidados da Baía de Paranaguá (Paraná). Nerftica. 1 : 79-89.

LANA, P. C .. ALMEIDA, M. V. 0 .. FREITAS, C. A. F .. COUTO. E. C. G .. CONTI. L. M. P .. GONZALEZ- PERONTI. A. L.. GILES. A .G .. LOPES. M. J. S., SILVA, M . H. C. & PEDROSO, L. A .. 1989.- Estrutura espacial de associações macrobênticas sublitorais da Gamboa Perequê (Pontal do Sul. Paraná). Neritica. 4 : 129-136.

MAURER. D. & VARGAS, J . A .. 1984. - Diversity of soft-bottom bentbos in a tropical estuary: Gulf of Nicoya. Costa Rica. Mar. Biol .. 81 : 97-106.

MAURER, 0 ., VARGAS. l. A. & DEAN, H .. 1988.- Polychaetous annelids from the Gulf of Nicoya, Cos ta Rica . /nr. Rev. Gesamren Hydrobiol .. 73 : 43-59.

NONATO. E. F. & LUNA. J. A. C .. 1970a.-Sobre alguns poliquetas de escama do Nordeste do Brasil. Bolm. lnst. Oceanogr .. São Paulo, 18 : 63-91 .

NONATO. E. F. & LUNA. J. A. C .. 1970b. - Anelídeos poliquetas do Nordeste do BrasiL I. Poliquetas bentôuicos qa costa de Alagoas e Sergipe. Bolm. fiJSt. Oceanogr., São Paulo. 19 : 57-130.

SANTOS, M. A .. 1979. - Macrofauna bémica do estuário do Rio Sergipe (Estado de Sergipe. Brasil). Doctor Thesis. Universidade de São Paulo. São Paulo. 128 pp.

STEPHENSON, W .. COOK, S. D. & RAPHAEL. Y. L 1977. - The effecl of a major flood on lhe macrobenthos of Bramble Bay. Queensland. Mem. Queensl. Mus .. 18 : 95-119.

STEPHENSON, W., WILLIAMS, W. T. & COOK, S . D., 1972.- Computer analyses of Petersen's o riginal data on bottom communitic . Eco/. Monogr .. 42 : 387-409.

ZUCON. M. H .. 1989. - Distribuição dos foraminf/eros e recomebas do esruário do rio Piouí-Sergipe. Mastc r Thcsis. Universidade Federal do Paraná, Curitiba. 54 pp.