The holoplankton of the Santa Catarina coast , southern Brazil

This paper presents information from different sampling surveys carried out along the Santa Catarina coast in order to outline the biogeographical characteristics of the zooplankton in this region and identify species or groups of species with potential use as bioindicators. Based on a checklist of species of the zooplankton community in the state, it was observed that, in the warmer months of the year, the fauna is similar to that of the states of Paraná and São Paulo (e.g. Creseis virgula f. virgula, Penilia avirostris; Acartia lilljeborgi and Oithona oswaldocruzi), while in the colder months there are coastal representatives of the fauna of Rio Grande do Sul (e.g. Acartia tonsa). However, the zooplankton consists predominantly of warm water species for most of the year, which is typical of Tropical Shelf Waters. Various species of zooplankton can be used as hydrological indicators, enabling a distinction to be made between coastal waters which are influenced by continental inputs (e.g. Paracalanus quasimodo and Parvocalanus crassirostris), common in the north of the state, and processes of upwelling (e.g. Podon intermedius) and the influence of the Subtropical Shelf Front (e.g. Pleopis polyphemoides), coming from the south. The different environments investigated present a zooplankton abundance that depends on the influence of continental inputs and the possibility of their retaining and contribution for the coastal enrichment, which varies seasonally.


INTRODUCTION
Zooplankton comprises groups of organisms commonly used as biological indicators, due to its short life cycle, high sensitivity, and abundance in aquatic ecosystems (Omori and Ikeda 1984).The knowledge on this community is vitally important in any type of environmental impact study for the installation and operation of enterprises in the coastal zone.Some zooplanktonic organisms are considered good hydrological indicators (Boltovskoy 1981), enabling the identification of different sources of water inputs that comprise the dynamic of an area.
In ecological terms, the knowledge on the zooplankton community provides information about the as the feeding habits of different dominant spe the community (Parsons et al. 1984).Besides its tance in the pelagic trophic chain as a point of c tion between the primary producers and the high els, this community presents many larvae of im fishing resources of commercial interest, such a taceans, decapods, molluscs and fish.
There is a lack of information concerning th plankton community of the Santa Catarina coast, has been highlighted in major review works on th ject presented by Valentin et al. (1994), Brandin (1997) and Lopes (2007).This lack of informa reinforced by the lack of access to data published entific congresses, or data generated by large o "main" -2011/5/12 -13:33 -page 576 -#2
drawn on the biogeographical characteristics of the Santa Catarina coast, compared with other areas that have been more exhaustively investigated to the north and south of the state, such as São Paulo, Paraná and Rio Grande do Sul.Therefore, drawing up a checklist of species recorded in a region enables, among other things, the establishment of the limits of geographical distribution of the species, comparison and confirmation of the existence of similarities among coastal regions, evaluation of the existence of species that indicate impacts and oceanographic conditions, and the establishment of key species in the use of monitoring of large-scale alterations, invasive species and test organisms applied to ecotoxicology.

STUDY AREA
The continental shelf of the state of Santa Catarina is located mainly within the Southeast Brazilian Continental Shelf (northern portion), though part of it lies on the Southern Brazilian Continental Shelf (southern portion), with its dividing point occurring at Santa Marta Cape (Hille et al. 2008) (Fig. 1).
The hydrological conditions of the Santa Catarina coast have been studied by Carvalho et al. (1998) and Hille et al. (2008), who highlight that the north coast is heavily influenced by continental inputs.On the south coast of the state, the phenomena of upwelling in summer and the influence of the plume from the Plata River and Sub-Antarctic Water (Subtropical Shelf Front) in winter (Piola et al. 2000) are key oceanographic processes that occur at Santa Marta Grande Cape.According to B.M. Castro Filho, unpublished data, Miranda (1982), Piola et al. (2000, 2005), Schettini et al. (2005) and Hille et al. (2008), the water masses occurring on the shelf are the Tropical Water (TW) of the Brazilian Current, with temperatures over 20°C and salinity higher than 36.4,and the South Atlantic Central Water (SACW), characterized by temperatures below 20 • C and salinity ranging from 36.4 to 34.5.The latter lies at greater depths and is responsible for strong thermal Antarctic Shelf Water, which originates from the mixing of the Malvinas Current with the discharge from the Prata River and Patos Lagoon, borders the south coast of Brazil as far as the region of Santa Marta Grande Cape in winter (Piola et al. 2000).
The north of Santa Catarina is influenced by various river systems, which change the concentrations of nutrients and the biological processes.These include the Itapocu, Itajaí-açu, Tijucas and Tubarão Rivers.In general, a decrease in salinity and an increase in concentrations of surface nutrients are seen in the areas around the river mouths of these systems (Bellotto et al. 1996, Schettini et al. 1998).The continental inputs, indented geography, and presence of numerous islands, together make up a coastline with various sub-environments, each of which has its own oceanographic features and biological species.
The environments for which more technical and scientific information have been gathered in recent years are shown in Figure 1 and Table I, and are mainly located to the north of the state of Santa Catarina: 1) The Babitonga Bay, on the north coast of Santa Catarina, is an environment which is characterized by an extensive formation of mangroves with continental inputs from three main rivers: The Palmital, the Cubatão and the Cachoeira Rivers (Kuroshima and Bellotto 1998, Cunha et al. 1999).
2) The Armação do Itapocoroy Bay, has been the object of intensive studies in recent years, as it is currently the largest mussel cultivation area in the state.According to Schettini et al. (1999), the waters of the Armação do Itapocoroy Bay are typically comprised of coastal waters (salinity lower than 34), with a seasonal temperature ranging from 19 • C to 28 • C. Both the salinity and the load of material in suspension are directly influenced by the Itajaí-açu River (Carvalho et al. 1998, Resgalla Jr andSchettini 2006), which has a plume of brackish water flowing northwards from the river mouth.
3) Navegantes Beach -a dissipative beach, heavily influenced by the inputs from the Itajaí-açu River  I).It also shows the identification of the rivers, and divisio continental shelf at Santa Marta Cape.
with 15,111 km 2 , which corresponds to 25% of the total area of the state.The influence of salinity, which characterizes the estuary itself, is observed 30 Km upstream from the river mouth due to the amplitude of the spring tide of 1.2 m and the pluviometric regimes (Schettini et al. 1998, Rörig 2005).
5) The Camboriú Bay highlights the influence of the Camboriú River on the salinity of the waters in the southern portion (F.Morelli, unpublished data, Schettini and Carvalho 1998).
6) The Zimbros Bay is influenced by the action of waves and by an extensive sedimentary plain, produced by inputs from the Tijucas River (Schettini

METHODOLOGY
Data were compiled on the density and specific composition of the zooplankton community and obtained in different coastal environments of the Santa Catarina coast and in different seasons of the year using different sampling equipment, but always in quantitative samplings.The samplings in estuaries and bays were carried out using WP-2 nets with a 200μm mesh size and 30 cm eter.All the trawls were carried out using a flowmeter to estimate the volume of filtered water.Abiotic data for water temperature and salinity were obtained in all samplings.Information from the samples is presented in Table I and summarized for each environment.
Besides the new data for zooplankton, the publications used in this work referring to the coastal region were as follows: Schettini et al. (2002) to the Babitonga  Bay; Duarte (1999), Resgalla Jr and Veado (2006) and     "main" -2011/5/12 -13:33 -page 579  A checklist of zooplankton species was drawn up, and comparisons were made with the fauna of the coastal environments to the north, São Paulo (C.L. De La Rocha, unpublished data) and Paraná (Montú 1987, Montú andCordeiro 1988), and to the south, in Rio Grande do Sul (Montú 1980, Montú andGloeden 1986, E. Muxagata, unpublished data), in order to determine the limits of distribution of species and establish the similarity between the areas.The compilation works of the plankton community for the Brazilian coast, carried The check list for this work did not inclu meroplankton occurring on the Santa Catarina which can be obtained in works with the lar Cirripedia, by Severino and Resgalla Jr (2005), of Decapoda, by Koettker and Freire (2006) For the classification of species by type of of occurrence, TS-P (Temperature, Salinity and ton) diagrams were created for the main coastal en ments of Santa Catarina involving all the samplin ods and the records of species observed, thereby iting the representative groups of the coastal and o areas, as well as the warm and cold waters.

RESULTS AND DISCUSSION
The marine zooplankton of the Santa Catarina c highly diverse, comprising 21 main groups and 15 distributed by family, genus, species and stages of opment (Table II).Copepoda had the highest taxo diversity, which was represented by 52 taxa on this DOMINANT ENVIRONMENTS AND SPECIES For the external continental shelf region, the zoo ton community is highly diverse.However, this di is less than that observed by M.J. Coelho, unpub data and Resgalla Jr and Montú (1995) for Chae tha, suggesting a predominance of the Tropical from the Brazilian Current, with salinities highe 33 and temperatures higher than 20 • C, and a certa tance from the western border of the Subtropica vergence Zone.This characteristic is confirmed predominance of species like the Copepoda Acar gligens, the Cladocera Evadne spinifera, and the tognatha Sagitta serratodentata.Despite the pres oceanic representatives of warm waters, coastal s typical of salinities lower than 31, such as Acartia "main" -2011/5/12 -13:33 -page 580 -#6

TABLE II
Taxa of zooplankton identified in different areas (according to the caption of Fig. 1) of the Santa Catarina coast.being Acartia lilljeborgi and Paracalanus quasimodo, followed by the genera Corycaeus and Temora.This prevalence is provided by waters with temperatures between 20 • C and 29.6 • C, and salinities between 25 and 35 (Fig. 2).Other well-represented organisms are the Larvacean Oikopleura dioica, the Chaetognatha Sagitta friderici and Sagitta enflata and, in particular, the Cla-influence of Tropical Water of the Brazilian C (Björnberg 1981, Ramirez 1981, Resgalla Jr and 1993, 1995).

582
CHARRID RESGALLA Jr. Itapocoroy Bay Babitonga Bay in colder waters (temperatures lower than 20 • C).In the north of the state, in the Babitonga Bay, A. lilljeborgi is dominant, while in the central region (the South Bay of Santa Catarina Island) and Conceição Lagoon (Odebrecht 1988), A. tonsa has higher densities during the spring and winter.It seems that the occurrence of A. tonsa depends not only on variations in salinity and temperature, but also on the characteristics of the environments covered and the availability of food in these environments (Paffenhoefer and Stearns 1988).This fact is corroborated by the absence of A. tonsa in the Itajaí-açu River estuary.
Other species of Copepoda also occur in significant quantities in the estuaries of Santa Catarina, including Oithona oswaldocruzi, Parvocalanus crassirostris, Paracalanus quasimodo, Temora stylifera, T. turbinata and Euterpina acutifrons, and the Chaetognath Sagitta friderici.The fauna of the estuarine zooplankton is very similar to that found in the estuaries of São Paulo, Paraná and Rio Grande do Sul (Table III).The difference lies in the occurrence and prevalence of species of Acartia, suggesting that the Santa Catarina coast is a transitional region between the fauna of the south (colder) and that of the north (warmer).
For the beach regions (Navegantes and Balneário Camboriú beaches), the similarity with the region of Rio Grande do Sul is due to the resident species of Mysidacea, which are typical of the surf zone of dissipative beaches comprised almost exclusively of Metamysidopsis elongata atlantica (Rörig et al. 1997, M.J. Novaes, unpublished data).

ENVIRONMENTS AND TOTAL DENSITY OF ZOOPLANKTON
In terms of density of zooplankton, the highest values are reported in estuarine environments or coastal zones close to or influenced by inputs from the rivers (Fig. 3).The freshwater input and its mixing within the Babitonga Bay favour a higher residence time of the waters and the development of the phytoplankton community and the herbivorous zooplankton in its environment.In the Armação do Itapocoroy Bay, despite it being a Bay of the Santa Catarina Island, the lower dyna the waters and inputs from small rivers lead to the opment of an abundant planktonic community.

BIOMASS
Data on zooplankton biomass are more limit the area of study.For the adjacent coastal reg the mouth of the Itajaí-açu River, Schettini et al. observed a maximum of 46.92 mg.m -3 in dry ma high organic carbon content, indicating high bio activity in the river plume.Data for biovolume a mass biomass were obtained from the Arvoredo M Biological Reserve, and indicated high values mum 0.51 mL.m -3 and 8.23 g.m -3 ) related to the rence of the Thaliacea Thalia democratica (L.M. F des, unpublished data, Resgalla Jr et al. 2004).

OUTBREAKS/BLOOMS
Seasonally, high densities of Thalia democrati the Eutecosomata Creseis virgula f. virgula normally lasting from the end of summer un autumn.These occurrences have been highligh other works, particularly for Thaliacea on the c São Paulo (Pires-Vanin et al. 1993), Santa Catarina Fernandes, unpublished data) and from Rio de J to Rio Grande do Sul (W.J.A. Amaral, unpub data), highlighting their relationships with lo with higher phytoplanktonic production that may volved with processes of localized upwelling alo coast (Resgalla Jr et al. 2001).In the Arvoredo M Biological Reserve, the occurrence of a higher dance of Thaliacea was also related to the varia concentration of the ammonicacal nitrogen in t ter column (Resgalla Jr et al. 2004).It is inte to note that both Thaliacea and Pteropoda pres same feeding strategy, i.e. they capture their fo filtering the water through the mucus, which small particles.This strategy makes them more e than other filterers and gives advantages in sho cesses of upwelling.These processes favor the "main" -2011/5/12 -13:33 -page 584 -#10

INDICATORS
For other constituents of the shelf, the use of cladocera as a hydrological indicator is highlighted.Podon intermedius was characterized as an indicator of SACW upwelling on the continental shelf of Rio de Janeiro (Valentin 1988) and São Paulo (C.E.F.Rocha, unpublished data), and its occurrence in the region adjacent to the Itajaí-açu River mouth and the Arvoredo Marine Biological Reserve was also related to these oceanographic processes (Fernandes 1998, Schettini et al. Santa Catarina (Muxagata andMontú 1999).In fact, the occurrence of this species is restricted to the coldest three months of the year.However, the absence of records of Evadne nordimanni, a typical species of the cold coastal waters of Argentina (Ramirez 1981) and the extreme south of Brazil (Resgalla Jr and Montú 1993), may indicate a significant alteration of the coastal branch of the Sub-Antarctic Water.
Finally, the species of the zooplankton community can be classified according to their preferential habits, "main" -2011/5/12 -13:33 -page 585 -#11  virgula, Penilia avirostris; Acartia lilljeborgi and Oithona oswaldocruzi).However, it presents representatives of colder waters (e.g.Pleopis polyphemoides; Podon intermedius and Acartia tonsa) during the winter and spring, which are characterized by the presence of the Subtropical Shelf Front and by processes of upwelling or inflow of the SACW.These processes increase the diversity of indicator species of waters of different origins, and indicate that the coast is an area of transition between the tropical, subtropical and temperate faunas between the south and southeast regions of Brazil.
However, the lack of information for the extreme south of the state points to the existence of a gap in knowledge and the small number of samplings around the area of upwelling of Santa Marta Cape.

ACKNOWLEDGMENTS
The author thanks the personnel of the Biological Oceanographic Laboratory, and the students, for their involvement in the area of planktology.In particular, thanks MSc.Oc.Ludmilla Dias Ad Vincula Veado for her participation and assistance in various analyses presented in this work.Also, the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for awarding the Research Grant, process 302165/2008-8.Palavras-chave: bioindicadores, cheklist, espécies costeiras, massas de água, ambientes costeiros, biogeografia.

Fig. 1 -
Fig. 1 -Location of the state of Santa Catarina (25 • 57 41 -29 • 23 55 S and 48 • 19 37 -53 • 50 00 W) in the south of Brazil, and environments in which the samplings of zooplankton were collected (TableI).It also shows the identification of the rivers, and divisio -#5 THE ZOOPLANKTON OF THE SANTA CATARINA COAST data to the Itajaí-açu River estuary and adjacent coastal region; M.J. Novaes, unpublished data to Camboriú Bay; L.M. Fernandes, unpublished data and Resgalla Jr et al. (2004) to the Arvoredo Marine Biological Reserve; and Resgalla Jr (2001), Veado and Resgalla Jr (2005) and D.C. Mori unpublished data to the South Bay (Santa Catarina Island).For the area of the external shelf, there are works on zooplankton groups carried out based on samples of major scientific cruises, such as the Projeto Uso e Exploração Racional do Ambiente Marinho (Rational Use and Exploitation of the Marine Environment) (24 • -29 • S) carried out in 1976 (M.R. Oliveira, unpublished data), CONVERSUT -Estudo da Área de Convergência Sub-tropical (Study of the Sub-tropical Area of Convergence) (28 • -34 • S) carried out from 1977 to 1981 (M.J. Coelho, unpublished data), SUESTE I (24 • -29 • S) carried out in 1982 (W.J.A. Amaral, unpublished data), SARP -Sardine/Anchovy Recruitment Project (28 • S) carried out in 1989, Projeto Sardinha 2 (23 • -28 • S) carried out in 1993 (Campos 2004), and ECOSAR 2 -Prospecção e Avaliação de Biomassa do Estoque de Sardinha, na Costa Sudeste, por Métodos Hidroacústicos (Prospecting and Evaluation of the Sardine Stock Biomass on the Southeast Coast, by Hydroacoustic Methods) (22 • -28 • S) carried out in 1995 (E.Muxagata, unpublished data).Additional information for Cnidaria was obtained in the works of Resgalla Jr et al. (2005) and Rossetto et al. (2007) relating to records of jellyfish accidents on the main beaches of the state.

Fig. 3 -
Fig.3-Mean of the total values of all data available for the zooplankton densities (Org.m -3 ) in different environments and waters for the Santa Catarina coast.

TABLE IV Zooplankton species by habitat and physical-chemical preferences of water occurrence.
region.Examples include A. lilljeborgi, P. quasimodo, T. tubinata and S. friderici, the oceanic species having more clearly defined distribution limits.However, the coastal species can be used as indicators of continental inputs in association with other more euryhalinas species, such as those of the Pseudodiaptomus and Para-enable the occurrence of processes of upwelling a influence of the Subtropical Shelf Front in the during the winter months.