Portada LAJAR-2013 (1).psd - Latin American Journal of Aquatic ...

More documents

Recommendations

Info

Lat. Am. J. Aquat. Res., 41(1): 42-56, 2013 Macrofauna of São Sebastião Channel, Southeastern Brazil DOI: 103856/vol41-issue1-fulltext-3 Research Article Spatial pattern of benthic macrofauna in a sub-tropical shelf, São Sebastião Channel, southeastern Brazil Ana Maria S. Pires-Vanin 1 , Emilia Arasaki 2 & Pablo Muniz 3 1 Instituto Oceanográfico, Universidade de São Paulo, Praça do Oceanográfico 191 São Paulo, 05508-120, Brasil 2 Escola Politécnica, Universidade de São Paulo. Av. Prof. Mello Moraes 2231, São Paulo, Brasil 3 Oceanografía y Ecología Marina, Facultad de Ciencias, Universidad de la República Iguá 4225, Montevideo, 11400, Uruguay ABSTRACT. Diversity and community organization of the benthic macrofauna were investigated along the São Sebastião Channel, northern coast of São Paulo State, Brazil, and related to sedimentary variables and organic load. These important outstanding soft bottom benthic habitats are characterized by their close proximity to sources of human impact. Sampling was undertaken seasonally, using a Van Veen grab (0.1 m 2 ) in 15 oceanographic stations, from November 1993 to August 1994. A total of 392 species were recorded and polychaetes completed nearly 50% of the fauna. Twenty three species were most numerous and frequent and comprised the baseline pool for the area. Sites were classified with respect to sediments in three site-groupings according to Arasaki et al. (2004). The finest-sediment site-group had significantly fewer species than coarser site-groups. The stations locate at the south opening and in the axis of the channel presented sediments with organic matter predominantly of marine origin, indicating the flow of open sea waters across the channel. These places showed also higher values of diversity and species richness. The site-group located along the insular side and in the channel north mouth, stood out for the significantly higher density. Although its relative small area the channel presented species richness similar to that found in the adjacent inner continental shelf. Comparisons between channel and adjacent shelf habitats are addressed in the light of ecological data. Keywords: diversity, macrofauna, continental shelf, São Sebastião Channel, Brazil, South Atlantic Ocean. Aspectos ecológicos de la macrofauna bentónica del Canal de São Sebastião, sudeste de Brasil RESUMEN. Se estudió la organización y diversidad de la comunidad macrobentónica de fondos blandos del canal de São Sebastião, costa norte del Estado de São Paulo, Brazil, relacionándolo con variables sedimentológicas y carga orgánica del sedimento. Estos fondos marinos importantes para especies bentónicas se caracterizan por encontrarse próximos a fuentes de impacto antrópico. El muestreo se desarrolló estacionalmente a lo largo de un año, en 15 estaciones oceanográficas, con una draga Van Veen (0.1 m 2 ), desde noviembre de 1993 hasta agosto de 1994. Se identificó un total de 392 especies, correspondiendo los poliquetos aprox. al 50% de la fauna. De este total, 23 especies fueron las más abundantes y frecuentes. Las estaciones fueron clasificadas según el sedimento en tres grupos de acuerdo con Arasaki et al. (2004). El grupo de estaciones caracterizado por sedimentos finos presentó significativamente menos especies que los otros dos grupos. Las estaciones localizadas en el extremo sur del canal y en su eje longitudinal presentaron sedimentos con materia orgánica predominantemente de origen marino, reflejando el flujo de aguas del océano abierto a través del canal. Estas estaciones mostraron también mayores valores de diversidad y riqueza de especies. Por otro lado, el grupo de estaciones localizado del lado insular y en la boca norte del canal presentó mayores densidades. A pesar de ser un área relativamente pequeña, el ecosistema del canal de São Sebastião presentó una riqueza de especies semejante a la registrada en la plataforma continental interna adyacente. La comparación de ambos ecosistemas se discute considerando los datos ecológicos disponibles. 42
43 Latin American Journal of Aquatic Research Palabras clave: diversidad, macrofauna, plataforma continental, Canal de São Sebastião, Brasil, océano Atlántico Sur. ___________________ Corresponding author: Ana Maria S. Pires-Vanin (amspires@usp.br) INTRODUCTION The study of marine communities has been contributed to the understanding of coastal areas dynamics. The knowledge of community organization in function of space and time is an important tool for analyzing ecological aspects of the ecosystem, including the maintenance of species diversity, stability (Koenig, 1999; Gray & Elliot, 2009), functional diversity (Hewitt et al., 2008) and biological niche invasion (Shea & Chesson, 2002). Environmental conditioning factors (such as sediment texture, oceanographic conditions and seasonal variation) can be frequently mixed up with sources of pollution (e.g. sewage discharges, oil pollution) being difficult to distinguish the effects of natural variation from anthropic effects on the faunal responses (Hyland et al., 2005; Spellerberg, 2005). The São Sebastião Channel is a peculiar area in the northern São Paulo State coast due the physical geography and oceanographic complexity (Furtado et al., 2008). It separates the main coast from the large São Sebastião Island and acts as a tunnel for winds, since changes in direction and velocity of the marine currents and in patterns of sedimentation has been frequently observed (Castro, 1990). The oceanographic regime and eutrophic condition differ seasonally. In early spring near the bottom layer starts the intrusion of the South Atlantic Central Water (SACW), cold, saline and nutrient rich (Castro & Miranda, 1998) from the continental slope to the coast, which promotes pulses of eutrophication at mid depths (Braga, 1999). In the winter SACW retreats to the shelf break and inner shelf is filled with the warm, low saline Coastal Water (Silveira et al., 2000). Besides, the area is affected by multiple human impacts. It houses the commercial port of São Sebastião, the oil terminal DTCS, which processes up to 55% of the Brazil’s oil (Zanardi et al., 1999a) and two sewage discharges. In spite of that, little is known about how the benthic fauna is structured or how diversity behaves in relation to species richness. Few investigations dealt with composition and spatial patterns of macrofaunal species in the São Sebastião Channel (Flynn et al., 1999; Muniz & Pires- Vanin, 2000), and with trophic relationships (Muniz & Pires, 1999). A functional analysis carried out recently using the AZTI’s Marine Biotic Index highlighted the relationship between faunal abundance and human activity in the area (Arasaki et al., 2004). However, a study about species diversity and distribution patterns of the assemblages is still lacking. The present paper investigates the community structure of the benthic macrofauna from São Sebastião Channel on a spatial scale. We hypothesize that the macrofauna structure will differ along the channel due to changes associated with sediment type, organic matter variation and the oceanographic regime. Given the facts, we expect changes in the structure of the macrofauna assemblages in those sites where high amounts of organic matter are present and the SACW signal is stronger. MATERIALS AND METHODS Study area The São Sebastião Channel is located on the northern coast of São Paulo State (23º41´-23º53.5´S, 45º19´- 45º30´W), Brazil (Fig. 1). It is situated parallel to the coast and separates the continent from the São Sebastião Island. The channel is approximately 25 km long with two relatively large openings (6-7 km wide), and a nearly 2 km narrow central part. The distribution of sediments is heterogeneous, patchy, and reflects the complex hydrological regime of the area (Furtado, 1995). A wide fine and well sorted sand “plateau” is situated to the south and contrasts with the northern shallow coarse sand bank. Also in the north, a counterclockwise vortex is responsible for the transport of fine grains to the south, promoting deposition of fine sediments at the continental margin (Castro, 1990). The central area is the deepest and narrowest part of the channel (about 40-45 m depth), and coarse grains found there mixed with mud are the consequence of the current speed increase due to the narrowing of the channel (Furtado, 1995). According to Castro (1990), in the channel the current flow is highly variable through the year, both in direction and speed, and always moving toward the NE, except in summer, when a two-layer water structure appears, the surface one to the SW and the deeper directed to the NE. This bottom current is associated with the penetration of the low temperature (35.4) water mass – the South Atlantic Central Water (SACW) (Miranda,
Page 2 and 3: Latin American Journal of Aquatic R
Page 4 and 5: Enox de Paiva-Maia, George Alves-Mo
Page 6 and 7: 2 INTRODUCCIÓN Las fluctuaciones e
Page 8 and 9: 4 Latin American Journal of Aquatic
Page 10 and 11: 6 escalas interanual e interdecadal
Page 12 and 13: 8 plataforma continental de Chile c
Page 14 and 15: 10 al., 2009), disminuciones en la
Page 16 and 17: 12 frecuencia presentes en esta pes
Page 18 and 19: 14 el fin de la temporada de surgen
Page 20 and 21: 16 Generación Índice Reclutamient
Page 22 and 23: 18 nacional de manejo ecosistémico
Page 24 and 25: 20 Bailey, K. 1989. Description and
Page 26 and 27: 22 symmetricus murphyi, in the open
Page 28 and 29: 24 Hurtado-Ferro, F., K. Hiramatsu
Page 30 and 31: 26 Parada, C., F. Colas, S. Soto-Me
Page 32 and 33: 28 conectividad de zonas de desove-
Page 34 and 35: 30 INTRODUCCIÓN El zooplancton com
Page 36 and 37: 32 Latin American Journal of Aquati
Page 38 and 39: 34 pequeños, incluso con una resol
Page 42 and 43: 38 calcular el Diámetro Circular E
Page 44 and 45: 40 Benfield, M., P. Grosjean, P.F.
Page 48 and 49: Macrofauna of São Sebastião Chann
Page 50 and 51: sorting. To estimate biomass, speci
Page 52 and 53: Density (ind m -2) Diversity (H’)
Page 54 and 55: Table 2. Density (nº ind m -2 ), b
Page 56 and 57: Macrofauna of São Sebastião Chann
Page 58 and 59: amphi-atlantic mollusc assemblages.
Page 60 and 61: Strickland, J.D.H. & T.R. Parsons.
Page 62 and 63: 58 pigmentación; en algunas especi
Page 68 and 69: 64 El porcentaje de individuos con
Page 70 and 71: 66 Gudger, E.W. & F.E. Firth. 1937.
Page 72 and 73: Lat. Am. J. Aquat. Res., 41(1): 68-
Page 74 and 75: pond surface area (Sup), pond deepn
Page 76 and 77: Nitrogen dynamics in low salinity w
Page 82 and 83: Burford, M.A. & K. Lorenzen. 2004.
Page 84 and 85: Lat. Am. J. Aquat. Res., 41(1): 80-
Page 86 and 87: Interactions between Guiana dolphin
Page 88 and 89: Interactions between Guiana dolphin
Page 90 and 91: and ships have slower displacement
Page 92 and 93: Valle, A.L. & F.C.C Melo. 2006. Alt
Page 96 and 97:
92 SGR i = ([(WT) i − (WT)(i-1)]
Page 98 and 99:
94 CFm (% TB) 4 3 2 1 0 Latin Ameri
Page 100 and 101:
96 Figure 8. a) Incidence of Philom
Page 102 and 103:
98 Japanese flounder, Paralichthys
Page 104 and 105:
100 Latin American Journal of Aquat
Page 106 and 107:
102 hidrodinámica y dinámica sedi
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
108 suspensión (Restrepo et al., 2
Page 114 and 115:
110 lodos litoclásticos pobremente
Page 116 and 117:
112 Sociedad Portuaria Regional de
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
118 globales disponibles del tiempo
Page 124 and 125:
Page 126 and 127:
122 Figura 7. Parámetro de mezcla
Page 128 and 129:
124 cuenca recibió los mayores cau
Page 130 and 131:
Lat. Am. J. Aquat. Res., 41(1): 126
Page 132 and 133:
treatment of the soil was performed
Page 134 and 135:
Effect of probiotic on bacterial an
Page 136 and 137:
Effect of probiotic on bacterial an
Page 138 and 139:
oth treatments, from the intermedia
Page 140 and 141:
probiotic, Bacillus subtilis E20, f
Page 142 and 143:
Page 144 and 145:
Cyanobacteria algae and some protoz
Page 146 and 147:
(1998) and Silva & Matsumura-Tundis
Page 148 and 149:
Zooplankton as bioindicator in trop
Page 150 and 151:
A close relationship among richness
Page 152 and 153:
Paturej, E. 2008. Assessment of the
Page 154 and 155:
Page 156 and 157:
Partial harvesting is useful in som
Page 158 and 159:
Table 1. Performance of Nile tilapi
Page 160 and 161:
Figure 4. Relationship between tota
Page 162 and 163:
Growth performance of Nile tilapia
Page 164 and 165:
espectively. At this time, the biom
Page 166 and 167:
of un-ionized ammonia. Montana Stat
Page 168 and 169:
164 incisor-like teeth at front of
Page 170 and 171:
Page 172 and 173:
Nematocyst study in ethanol preserv
Page 174 and 175:
Page 176 and 177:
Epitoquia en P. australis en aguas
Page 178 and 179:
Epitoquia en P. australis en aguas
Page 180 and 181:
the west coast of Ireland. Sci. Pro
Page 182 and 183:
178 El proceso de doble difusión o
Page 184 and 185:
Page 186 and 187:
182 You, Y. 2002. A global ocean cl
Page 188 and 189:
184 pigments, although much new tax
Page 190 and 191:
Page 192 and 193:
188 activity of seaweeds extracts a
Page 194 and 195:
Page 196 and 197:
192 (Müller & Henle, 1841) (Myliob
Page 198 and 199:
Page 200 and 201:
Figure 2. Gill filaments showing pl
Page 202 and 203:
Gbankoto, A., C. Pampouli, A. Marqu
Page 204 and 205:
200 pesquería, destacan estimacion
Page 206 and 207:
Page 208 and 209:
Page 210 and 211:
206 entre estaciones correspondient
Page 212:
208 partial local retention and tra
show all

Portada LAJAR-2013 (1).psd - Latin American Journal of Aquatic ...

Create successful ePaper yourself

Delete template?

Save as template?