Effect of microhabitat distribution and substrate roughness on barnacle Tetraclita stalactifera (Lamarck, 1818) settlement

Abstracts

Studies were carried out on microhabitat distribution and substrate roughness on barnacle settlement at Cabo Frio region, Rio de Janeiro, Brazil. Ten commercial blocks of granite rock (100 cm²) were attached to rocky coast at 0.6 tide level (5 smooth blocks and 5 rough with 20 holes). Experiment was conduced for five weeks, with repetitions each week. Settlement was higher on rough (398 individuals) than on smooth blocks (38 individuals) on the same week. There was no significant difference between settlement in the centre of the block and at the edge. Significant differences observed among weeks were affected by the variability of cyprid larvae density. This result showed that roughness was an important variable to be considered on barnacle settlement.

Barnacle; Substrate roughness; Settlement; upwelling


A rugosidade dos substratos afeta o assentamento de larvas de invertebrados marinhos, tanto em substratos naturais quanto em substratos artificiais. Elevadas taxas de assentamento são esperadas em substratos com maior rugosidade/ heterogeneidade devido aos microhabitats formados e também à alteração do movimento da água sobre o substrato. Neste estudo foi avaliado o assentamento de cracas em substratos lisos e rugosos, dispostos na região de Cabo Frio, RJ, Brasil (22(0) 59' S, 42(0) 02' W). Dez blocos de granito comercial (100 cm²) foram fixados ao costão rochoso no nível de maré 0,6. Cinco blocos eram lisos (controle) e cinco blocos apresentavam 20 pequenas cavidades (5 mm fi, 3mm profundidade) regularmente distribuídas no bloco. O experimento foi conduzido por 7 dias e repetido em 5 semanas. Como resultado observamos o maior assentamento nos blocos rugosos (Max. 398 indivíduos) do que nos blocos lisos (Max. 38 ind.). Não foi observada diferença significativa entre o número de assentados no centro do bloco em relação à sua margem, indicando que não houve o efeito de borda. Foram observadas diferenças significativas no assentamento entre as 5 semanas do experimento, afetada pela maior presença de larvas cípris durante algumas semanas. Este experimento mostra como a variabilidade estrutural pode influenciar o assentamento de larvas de Cirripedia.


BIOLOGICAL AND APPLIED SCIENCES

Effect of microhabitat distribution and substrate roughness on barnacle Tetraclita stalactifera (Lamarck, 1818) settlement

Luís Felipe SkinnerI, II; Ricardo CoutinhoII, * * Author for correspondence

IUniversidade do Estado do Rio de Janeiro; FFP; Rua Dr. Francisco Portela, 794; Paraíso; 24435-000; lskinner@uerj.br; São Gonçalo - RJ - Brazil

IIInstituto de Estudos do Mar Almirante Paulo Moreira - IEAPM; coutinho@nitnet.com.br; São Gonçalo - RJ - Brazil

ABSTRACT

Studies were carried out on microhabitat distribution and substrate roughness on barnacle settlement at Cabo Frio region, Rio de Janeiro, Brazil. Ten commercial blocks of granite rock (100 cm2) were attached to rocky coast at 0.6 tide level (5 smooth blocks and 5 rough with 20 holes). Experiment was conduced for five weeks, with repetitions each week. Settlement was higher on rough (398 individuals) than on smooth blocks (38 individuals) on the same week. There was no significant difference between settlement in the centre of the block and at the edge. Significant differences observed among weeks were affected by the variability of cyprid larvae density. This result showed that roughness was an important variable to be considered on barnacle settlement.

Key words: Barnacle, Substrate roughness, Settlement, upwelling

RESUMO

A rugosidade dos substratos afeta o assentamento de larvas de invertebrados marinhos, tanto em substratos naturais quanto em substratos artificiais. Elevadas taxas de assentamento são esperadas em substratos com maior rugosidade/ heterogeneidade devido aos microhabitats formados e também à alteração do movimento da água sobre o substrato. Neste estudo foi avaliado o assentamento de cracas em substratos lisos e rugosos, dispostos na região de Cabo Frio, RJ, Brasil (220 59' S, 420 02' W). Dez blocos de granito comercial (100 cm2) foram fixados ao costão rochoso no nível de maré 0,6. Cinco blocos eram lisos (controle) e cinco blocos apresentavam 20 pequenas cavidades (5 mm f , 3mm profundidade) regularmente distribuídas no bloco. O experimento foi conduzido por 7 dias e repetido em 5 semanas. Como resultado observamos o maior assentamento nos blocos rugosos (Max. 398 indivíduos) do que nos blocos lisos (Max. 38 ind.). Não foi observada diferença significativa entre o número de assentados no centro do bloco em relação à sua margem, indicando que não houve o efeito de borda. Foram observadas diferenças significativas no assentamento entre as 5 semanas do experimento, afetada pela maior presença de larvas cípris durante algumas semanas. Este experimento mostra como a variabilidade estrutural pode influenciar o assentamento de larvas de Cirripedia.

INTRODUCTION

Settlement of marine invertebrates in natural and artificial substrate is in general, affected by roughness of substrate and hydrodynamics (Judge and Craig, 1997). Pits, depressions and crevices affect water movement over substrate (Abelson, 1997; Abelson and Denny, 1997) and consequently, arrival of larvae. These irregularities of substrate also change abiotic conditions close to them, increasing, for example, moisture and reducing direct sunlight during air exposure. At immersion times, it could increase or reduce water movement.

Studies under laboratory or field condition have evaluated the effects of different levels of substrate roughness (Bourget et al., 1994; Harvey et al., 1995; Harvey and Bourget, 1997) demonstrating its effect on arrival of larvae as well as on their behaviour. Many authors suggest that behaviour is responsible for small-scale patterns of distribution while oceanographic conditions are responsible for large-scale distribution pattern (Eckman, 1996; Underwood and Chapman, 1996; Judge et al., 1998).

The aim of this work was to estimate Tetraclita stalactifera settlement rate related to substrate roughness (presence or absence of crevices) and position of these crevices (centre or edge). The hypothesis tested was that barnacle settlement is different among blocks. If the first hypothesis was true a second hypothesis was tested and there was no difference on barnacle settlement in the edge or centre of block (no edge effect). This study is part of a wide program of barnacle population dynamic study at Cabo Frio region, Brazil and was important to show differences on settlement due to substrata roughness, mainly on tropical region.

MATERIALS AND METHODS

Study site

This study was conducted at Ponta da Cabeça (220 59' S, 420 30' W) in Arraial do Cabo, Brazil. This region was chosen due to the occurrence of an upwelling event caused by prevailing northeast wind, topographical and geographical characteristics of seafloor and coastline (Valentin, 1984; 1988). Wind condition and/or site location may influence distribution of tropical and temperate species (Valentin, 1984; Valentin and Monteiro-Ribas, 1993; Valentin and Coutinho, 1990; Guimaraens and Coutinho, 2000). Tidal regime is semidiurnal with a 1.4 m range and slope of the rocky coast at the study site varies from 450 to 900.

Experimental design

Ten blocks (100 cm2 area) of commercial granite rock were used. Five blocks were smooth and five contained twenty holes (5 mm Ø , 3 mm deep, 15 mm distance each other – thereafter refereed as rough blocks). Blocks were attached to rock with an epoxy adhesive (Tubolite ®) at the Tetraclita zone (0.6 m). The position of each block was randomly sorted out in a 20 m transect. Settled barnacles were counted and, in rough blocks, their position was assigned to compare it for the same treatment (inside or outside hole; edge or centre of block). Counts were done up to one week and then, blocks were strongly brushed to remove all settled barnacles and other species. The total experiment duration was 5 weeks (from April to May 2000).

Data analysis

Student t tests were used to compare in each week, total settled barnacles on smooth and rough blocks. A one-way ANOVA was also performed to test differences for barnacle position (edge or centre) at rough blocks (one factor – position, Type I) (Zar, 1984). ANOVA test was used to increase the power of analysis since the number of holes on edge and centre of blocks are different and all holes of all blocks were used and not only mean values.

RESULTS

Mean sea surface temperature in five weeks of experiment was 21.8 ºC ± 2.4 and observations were conduced both during upwelling and non-upwelling conditions. The mean water temperatures for each week was 19.3 0C ± 2.9; 23.3 0C ± 2.8; 18.2 0C ± 2.8; 22.8 0C ± 2.8 and 21.6 0C ± 2.4 respectively. A surface temperatures value below 20 0C indicate subsidence events (Valentin, 1984). These differences in water temperature could also indicate differences on larval availability, lower during upwelling times (Skinner and Coutinho, 2002).

Barnacle settlement was always higher on rough blocks. Lowest mean number of settled barnacles on rough blocks was 2.2 and the highest was 320.0 individuals (max. 398 ind.). For smooth blocks, this number was 0.0 and 12.0 (max. 38) individuals respectively (Table 1). The results showed that settlement on rough blocks could be up to 74 times higher than on smooth ones. Significant differences were observed for settlement on smooth and rough blocks using t test for the same week as show on Table 1.

ANOVA test applied for barnacle settlement on edge or centre of rough blocks showed no significant difference for position of settled barnacles (Table 2).

DISCUSSION

Results showed that settlement of barnacle larvae was influenced by substrate heterogeneity. Increasing substrate heterogeneity increased settlement. This fact was related to holes on substrate, which might have changed water flow and also physical characteristics of substrate, like moisture retention, creating microhabitats and then, favouring settlement of cyprids. Also, larval retention could have increased by flow over substrata and inside the crevices (Abelson, 1997; Abelson and Denny, 1997).

In barnacle and/ or communities studies, the use of smooth or low roughness substrate like plain PVC, fibreglass, glass or wood is usual (Silva et al., 1980; 1989; O'Connor and Richardson, 1994), contrasting with studies in natural rocky substrate (Dineen Jr and Hines, 1994; Underwood and Chapman, 1996, Menge, 2000). Our results showed that this increase in settled number could be up to 74 times in roughed blocks, hence, the use of smooth or low roughness substrate could under estimate the number of settlers (Chabot and Bourget, 1988; Bourget et al., 1994; Lemire and Bourget, 1996; Wahl and Hoppe, 2002) compared to natural substrate studies.

Larval swimming capacity and/or behaviour may have influenced settlement at rough blocks. Over smooth substrate, water flows with high velocity, shows no turbulence and it may prevent settlement of cyprids (Judge and Craig, 1997). While studying larval behaviour, Harvey and Bourget (1997), using arborescent structures, showed that the water flow drove larvae to specific points of substrate called "hot spots". After substrate encounter, larval behaviour is important to settlement. Many other studies have showed the importance of larval behaviour (Pineda, 1994; Jeffery, 2000; Navarrete and Wieters, 2000) on larval settlement choice and on population and community dynamics. Sometimes, substrate heterogeneity could reduce settlement through behaviourally rejection of sites by barnacle settlers as registered for B.improvisus (Berntsson et al., 2000), but this was not the case in present work. Barnacles attachment also increases heterogeneity. Some researchers that investigate natural heterogeneity generated by barnacles (Jarret and Pechenik, 1997; Jeffery, 2000) showed that clumps of barnacles increase larval settlement close to adults. Nevertheless, in these works, it is difficult to separate effects of substrate heterogeneity from chemical cues generated by barnacle adults or shells of dead barnacle. In this experiment, all substrate were immersed free of cues and weekly, all settled barnacles were removed, reducing these cues. Substrate heterogeneity was the main tested characteristic in this case. Although bacteria, protozoan, algae and organic molecules over substrate could act as signals and influence barnacle settlement (Dineen Jr and Hines, 1994; O'Connor and Richardson, 1998; Menge, 2000), in this experiment, blocks were exposed to the same field conditions and we do not expect to have difference caused by these factors.

Position of crevices on edge or centre has no influence on number of settled barnacles. In many studies (Keough, 1984; Tanaka and Magalhães, 2002), edge effect has been described to affect settlement or succession due to the size of available area or increasing heterogeneity. In our experiment, size of blocks and its attachment closely to natural and heterogeneous substrata did not produce edge effect on barnacle settlement. Hence, water flow, larval flux and site selection acted at the same scale on rough blocks. This revealed that a 100cm2 area could be used to estimate larval settlement in that region.

Differences observed on number of settlers for all 5 weeks of experiment could be related to upwelling or subsidence conditions that could influence larval availability and also, barnacle settlement rate, increasing or decreasing it (Skinner and Coutinho 2002). The results showed that substrate heterogeneity could increase larval settlement and this would be important too estimating changes on population or community dynamics on natural or artificial substrate.

ACKNOWLEDGEMENTS

LFS would like to thank IEAPM and PPGB-UERJ for facilities and equipments. A PhD Scholarship was granted from CAPES to LFS. RC was supported by a fellowship from CNPq.

Received: April 07, 2003;

Revised: January 14, 2004;

Accepted: July 12, 2004.

  • Abelson,A. (1997), Settlement in flow, upstream exploration of substrate by weakly swimming larvae. Ecology, 78 : (1), 160-166.
  • Abelson, A. and Denny, M. (1997), Settlement of marine organisms in flow. Annu.Rev.Ecol.Syst, 28, 317-339.
  • Bourget, E.; DeGuise, J. and Daigle, G. (1994), Scales of substratum heterogeneity, structural complexity, and the early establishment of a marine epibenthic community. J. Exp. Mar. Biol. Ecol, 181, 31-51.
  • Berntsson, K. M.; Jonsson, P. R.; Lejhall, M and Gatenholm, P. (2000), Analysis of behavioural rejection of micro-textured surfaces and implications for recruitment by the barnacle Balanus improvisus. J.Exp. Mar.Biol.Ecol, 251, 59-83.
  • Chabot, R. and Bourget, E. (1988), Influence of substratum heterogeneity and settled barnacle density on the settlement of cyprids larvae. Marine Biology 97, 45-56.
  • Dineen Jr, J. F. and Hines, A. H. (1994), Larval settlement of the polyhaline barnacle Balanus eburneus (Gouldi), cue interactions and comparisons with two estuarine congeners. J. Exp. Mar. Biol. Ecol, 179, 223-234.
  • Eckman, J. E. (1996), Closing the larval loop, linking larval ecology to the population dynamics of marine benthic invertebrates. J. Exp. Mar. Biol. Ecol, 200, 207-237.
  • Guimaraens, M. A. and Coutinho, R. (2000), Temporal and spatial variations of Ulva spp. and water properties in the Cabo Frio upwelling region of Brazil. Aquatic Botany, 66,101-114.
  • Harvey, M. and Bourget, E. (1997), Recruitment of marine invertebrates onto arborecent epibenthic structures, active and passive processes acting at different spatial scales. Mar. Ecol. Progr. Ser, 153, 203-215.
  • Harvey, M.; Bourget, E. and Ingram, R. G. (1995), Experimental evidence of passive accumulation of marine bivalve larvae on filamentous epibenthic structures. Limnology and Oceanography 40 : (1), 94-104.
  • Jarret, J. N. and Pechenik, J. A. (1997), Temporal variation in cyprid quality and juvenile growth capacity for an intertidal barnacle. Ecology 78 : (5), 1262-1265.
  • Jeffery, C. J. (2000), Settlement in different-sized patches by the gregarious intertidal barnacle Chamaesipho tasmanica Foster and Anderson in New South Wales. J. Exp. Mar. Biol. Ecol, 252, 15-26.
  • Judge, M. L. and Craig, S. F. (1997), Positive flow dependence in the initial colonization of a fouling community, results from in situ water current manipulations. J. Exp. Mar. Biol. Ecol, 210, 209-222.
  • Judge, M. L.; Quinn, J. F. and Wolin, C. L. (1998), Variability in recruitment of Balanus glandula (Darwin, 1854) along the central California coast. J. Exp. Mar. Biol. Ecol., 119, 235-251.
  • Keough, M. J. (1984), Effects of patch size on the abundance of sessile marine invertebrates. Ecology 65 : (2), 423-427.
  • Lemire, M. and Bourget, E., (1996), Substratum heterogeneity and complexity influence micro-habitat selection of Balanus sp. and Tubularia crocea larvae. Mar.Ecol.Progr.Ser, 135, 77-87.
  • Menge, B. A. (2000), Recruitment vs. Post recruitment processes as determinants of barnacle population abundance. Ecol.Mogr, 70 : (2), 265-288.
  • Navarrete, S. A. and Wieters, E. A. (2000), Variation in barnacle recruitment over small scales, larval predation by adults and maintenance of community pattern. J. Exp. Mar. Biol. Ecol, 253, 131-148.
  • O'Connor, N. and Richardson, D. L. (1994), Comparative attachment of barnacle cyprids (Balanus amphitrite Darwin, 1854; B. improvisus Darwin, 1854; and B.eburneus Gould, 1841) to polystyrene and glass substrata. J. Exp. Mar. Biol. Ecol, 183, 213-225.
  • O'Connor, N. and Richardson, D. L. (1998), Attachment of barnacle (Balanus amphitrite Darwin) larvae, responses to bacterial films and extracelular materials. J. Exp. Mar. Biol. Ecol, 226, 115-129.
  • Pineda, J. (1994), Spatial and temporal patterns in barnacle settlement rate along a southern California rocky shore. Mar. Ecol. Progr. Ser, 107, 125-138.
  • Silva, S. H. G.; Nunes, A. J. B.; Alves, M. C. S. and Lage, V. A. (1980), Contribuição ao estudo das comunidades incrustantes que ocorrem na Baía da Guanabara, Rio de Janeiro, Brasil. Resultados preliminares. Rev.Bras.Biol, 40 : (2), 367-382.
  • Silva, S. H. G.; Junqueira, A. O. R.; Martins-Silva, M. J.; Zalmon, I. R. and Lavrado, H. P. (1989), Fouling and wood-boring communities on the coast of Rio de Janeiro, Brazil. In Neves, C. and Magon, O.T. (Eds). Coastlines of Brazil, American Society of Civil Engineers, New York. pp. 95-109.
  • Skinner, L. F. and Coutinho, R. (2002), Preliminary results on settlement of the barnacles Tetraclita stalactifera and Chthamalus bisinuatus on a Brazilian tropical rocky shore under upwelling conditions. Invertebrate Reproduction and Development, 41 : (1-3), 151-156.
  • Tanaka, M. O. and Magalhães, C. A. (2002), Edge effects and succession dynamics in Brachidontes mussel beds. Mar.Ecol.Prog.Ser, 237, 151-158.
  • Underwood, A. J. and Chapman, M. G. (1996), Scales of spatial patterns of distribution of intertidal invertebrates. Oecologia, 10, 212-224.
  • Valentin, J. L. (1984), Spatial structure of the zooplancton comunity in the Cabo Frio region (Brazil) influenced by coastal upwelling. Hydrobiologia, 113, 183-199.
  • Valentin, J. L. (1988), A dinâmica do plancton na resurgência de Cabo Frio - RJ. Memórias do III Encontro Brasileiro de Plâncton pp. 26-35.
  • Valentin, J. L. and Coutinho, R. (1990), Modelling maximum chlorophyll in the Cabo Frio (Brazil) upwelling, a preliminary approach. Ecological Modelling, 52, 103-113.
  • Valentin, J. L. and Monteiro-Ribas, W. M. (1993), Zooplankton community structure on east-southeast Brazilian continental shelf (18 23şS latitude). Continental Shelf Research, 13 : (4), 407-424.
  • Wahl, M. and Hoppe, K. (2002), Interactions between substratum rugosity, colonization density and periwinkle grazing efficiency. Marine Ecol. Progr. Ser 225, 239-249.
  • Zar, J. H. (1984) Biostatistical analysis Ed. Prentice Hall, New York.

  • *
    Author for correspondence

Publication Dates

  • Publication in this collection
    15 Apr 2005
  • Date of issue
    Jan 2005

History

  • Accepted
    12 July 2004
  • Received
    07 Apr 2003
  • Reviewed
    14 Jan 2004
Instituto de Tecnologia do Paraná - Tecpar Rua Prof. Algacyr Munhoz Mader, 3775 - CIC, 81350-010 Curitiba PR Brazil, Tel.: +55 41 3316-3052/3054, Fax: +55 41 3346-2872 - Curitiba - PR - Brazil
E-mail: babt@tecpar.br