Spatial distribution of Polychaeta in a soft-bottom community at Saco do Céu, Ilha Grande, Rio de Janeiro, Brazil (original) (raw)
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Polychaete Distribution and Abundance in Intertidal Flats of Paranaguá Bay (SE Brazil)
Bulletin of Marine Science -Miami-
The effects of plant zonation on polychaete distribution and abundance were studied along an environmental gradient in intertidal flats of Paranaguá Bay (SE Brazil). Two polychaete stocks with marked preference for specific haline regimes were recognized with a low degree of spatial overlap in species distribution. Species richness and abundance were lower in the mesohaline sector, characterized by fine sediments and high organic carbon content, than in the high-energy euhaline sector, dominated by moderately sorted fine sands low in organic carbon content. Faunal differences were primarily defined by salinity and environmental energy gradients and only secondarily by the ability of polychaetes to discriminate among unvegetated, salt marsh or mangrove swamp habitats.
Distribution patterns of interstitial polychaetes in sandy beaches of southern Brazil
Marine Ecology, 2009
This study describes the distribution patterns of interstitial polychaetes along morphodynamic gradients on six exposed sandy beaches in Santa Catarina and Paraná (South Brazil). Three random transects were sampled at two points on each beach, one at the swash and another at the surf zone, in winter and summer conditions. Six sediment replicates were collected at each sampling point using a corer of 4.6 cm internal diameter that removed 10 cm into the sediment. Abundance and composition of interstitial polychaete were correlated to wave height, slope, grain size, CaCO3, chlorophyll a, omega indexes, temperature and relative tide range using a canonical correspondence analysis (CCA). A factorial ANOVA showed that taxa richness, mean density and Shannon’s diversity were significantly higher at the reflective beaches, but average values differ significantly between transects and these differences change according to the beach zones on both sampling dates. PERMANOVA showed that polychaete associations differ among transects according to the beach zones. The composition of interstitial polychaete associations was significantly correlated to beach morphodynamics and features (P < 0.01). Polychaete associations of reflective beaches were more diverse than in other morphodynamic states. Intermediate beaches may also sustain diverse associations due to temporal variability of the morphodynamic patterns. Beaches presenting extreme dissipative morphodynamics and compacted sediments appear to be unfavourable for the occurrence of interstitial polychaetes.
Trophic structure of polychaetes in the São Sebastião Channel (southeastern Brazil)
Marine Biology, 1999
Between November 1993 and August 1994, the spatial and seasonal trophic structures of polychaete annelids were studied in the SaÄ o SebastiaÄ o Channel, southeastern Brazil, located between the mainland of SaÄ o Paulo State and SaÄ o SebastiaÄ o Island. Four sampling surveys were carried out with a van Veen grab of 0.1 m 2 at 15 stations. A total of 12 003 individuals (126 species) was recorded and separated into 14 feeding guilds. Data were analysed with univariate and multivariate techniques (cluster and canonical correspondence analysis). Results showed a strong correlation between trophic groups and sediment variables such as grain size and organic carbon content. The Channel was dominated by surface deposit-feeders, followed by carnivores. Suspension-feeders were con®ned to medium and coarse sandy sites, environments with high energy. Bottoms where silt, clay and organic carbon predominated showed low polychaete densities. In these places the pollution induced by the sewage discharge from AracË a underwater emissions and by the oil terminal Dutos e Terminais Centro Sul was evident. There were no signi®cant seasonal variations in the trophic structure over the study period, except in fall when densities were low. The polychaetes' relationships within the benthic system are discussed.
Journal of the Marine Biological Association of the United Kingdom, 2013
Several studies have been conducted to explain patterns of the abundance, richness and diversity of sandy-beach macrofauna; however, such analyses have ignored the overall functional structure of macrofauna communities. Few studies have examined polychaete feeding guilds on sandy beach environments. To examine the effects of environmental factors on polychaete feeding guilds on sandy beaches, 12 sandy beaches from five islands in Sepetiba Bay were sampled. A total of 24 polychaete morphospecies, grouped among 21 families, were identified in these sandy beaches. The polychaete species were classified into 10 feeding guilds, and the SDT guild (suspended-deposit feeders, discretely motile, with tentacles) was the most abundant feeding guild, with 34.2% of total number of organisms. The highest trophic importance index and index of trophic diversity values were recorded on the sheltered beaches. A canonical correspondence analysis showed that the exposure rate, beach length, and grain size of the beach sediment significantly affected the polychaete feeding guild distribution and abundance. We can conclude that sheltered beaches have a higher diversity of feeding guilds than exposed beaches and that the biological descriptors of the feeding guilds are directly associated with the grain size of the sediment.
Polychaetes play an important role in the structure and functioning of benthic communities in mangroves; however, knowledge about these organisms in the Maranhão Amazon coast is scarcity. This study analyzed the ecological aspects of polychaete community in the Quebra Pote mangrove in Maranhão State. Four sampling campaigns were carried out during both rainy and dry periods between November 2013 and July 2014, using 100 meters long transects set perpendicular to the waterline at three zones 50 m between them. A total of 521 organisms were identified belonging to ten families and 15 species; Nephtys simoni, Notomastus sp., and Paraonis sp. represented 58.92 % of all samples. Mobile deposit-feeders polychaetes were dominant and abundant. The Quebra Pote mangrove showed high values of diversity and evenness. The spatial distribution indicated that several species such as magellanica were present in all mangrove zones. The diversity and abundance of polychaetes were greater in lower mesolittoral (Zone 1), with a dominance of Avicennia schaueriana. The abundance of polychaetes decreased along transects from the lower mesolittoral to upper mesolittoral areas, suggesting that the presence of domestic sewage effects supersedes the vegetation effect. RESUMEN Los poliquetos desempeñan un importante papel en la estructura y funcionamiento de las comunidades bentónicas de manglares; sin embargo, el conocimiento sobre estos organismos permanece escaso en la costa amazónica de Maranhão, Brasil. Este estudio analizó los aspectos ecológicos de la comunidad de poliquetos del manglar Quebra Pote, Estado de Maranhão. Se realizaron cuatro recolectas durante el período de secas y lluvias, entre noviembre 2013 y julio 2014, se delimitó un transecto de 100 metros de longitud, perpendicular a la línea de agua, con tres zonas distantes entre sí de 50 m. Se cuantificaron 521 individuos distribuidos en diez familias y 15 especies; Nephtys simoni, Notomastus sp. y Paraonis sp., correspondieron al 58,92 % del total muestreado. Los poliquetos detritívoros móviles fueron dominantes y abundantes. El manglar Quebra Pote presentó elevados valores de diversidad y equidad. En la distribución espacial, se observó que varias especies estuvieron presentes en todas las zonas del manglar, por ejemplo La diversidad y abundancia de poliquetos fueron mayores en el mediolitoral inferior (Zona 1), con predominio de Avicennia schaueriana. A lo largo de las zonas se observó que la abundancia de poliquetos decrece del mediolitoral inferior hacia al mediolitoral superior, probablemente como consecuencia del desagüe doméstico, que suplantó el efecto de la vegetación.
Polychaete assemblage of an impacted estuary, Guanabara Bay, Rio de Janeiro, Brazil
2009
Avenida Nazaré, 481, 04263-000, São Paulo, SP, Brasil) mdst@usp.br A B S T R A C T Thirty-eight stations were sampled in Guanabara Bay, Rio de Janeiro, Brazil, to assess the spatio-temporal diversity and biomass of sublittoral polychaetes. Samples were collected during the dry (September 2000) and rainy season (May 2001) in shallow sublittoral sediments. The polychaete spatial composition showed a heterogeneous distribution throughout the bay. A negative gradient of diversity and biomass was observed towards the inner parts of the bay and sheltered areas. A wide azoic area was found inside the bay. Some high-biomass and low-diversity spots were found near a sewage-discharge point. In these areas, the polychaete biomass increased after the rainy season. A diversified polychaete community was identified around the bay mouth, with no dramatic changes of this pattern between the two sampling periods. Deposit-feeders were dominant in the entire study area. The relative importance of carnivores and omnivores increased towards the outer sector, at stations with coarse sediment fractions. Guanabara Bay can be divided into three main zones with respect to environmental conditions and polychaete diversity and biomass patterns: A) High polychaete diversity, hydrodynamically exposed areas composed of sandy, oxidized or moderately reduced sediments with normoxic conditions in the water column. B) Low diversity and high biomass of deposit and suspension-feeding polychaete species in the middle part of the bay near continental inflows, comprising stations sharing similar proportions of silt, clay and fine sands. C) Azoic area or an impoverished polychaete community in hydrodynamically low-energy areas of silt and clay with extremely reduced sediments, high total organic matter content and hypoxic conditions in the water column, located essentially from the mid-bay towards the north sector. High total organic matter content and hypoxic conditions combined with slow water renewal in the inner bay seemed to play a key role in the polychaete diversity and biomass. Sedimentation processes and organic load coming from untreated sewage into the bay may have negatively affected the survivorship of the fauna.
Pan American Journal of Aquatic Sciences, 2013
This study describes the spatial and temporal variations in the biodiversity of polychaetes in an area subjected to different anthropogenic activities (fishing, tourism and oil refinery activities). It involved the evaluation of sediment data and biological assessment of these invertebrates in 20 stations distributed along the coast line of the "Península de Paraguaná", being sampled in 10 occasions, between july-2008 and September-2010. Sediment analyses showed a northern zone dominated by the sand fraction, and a southern zone with a large content of mud and a high percentage of organic matter. A total of 18 taxonomic groups were recorded, where 7368 individuals of the polychaete group were identified, belonging to 35 families, with Capitellidae (35%) and Spionidae (21%) as the most abundant. The family richness oscillated between 1,6 nFam/Cam (S19) and 6,8 nFam/Cam (S16), while the higher densities were reported in the 18 and 19 stations, reaching the maximum value of 1789,73 ± 3152,86 ind/m 2 (S18). These high values belonged to capitellids and spionids (> 6000 ind/m 2), and suggested the existence of a local disturbance event that is associated with the oil refinery activities. This study showed how the analyses of biological data can be useful for detecting the influence of anthropogenic impact events when chemical information is not available.
Deep Sea Research Part II: Topical Studies …, 2004
This paper describes diversity patterns of the polychaete fauna in Bah! ıa Todos Santos (Pacific Ocean, Baja California, Mexico). Thirty-nine stations were sampled in October 1994. Measurements of depth, temperature, salinity, dissolved oxygen, organic content and sediment particle size were made. Polychaetes constituted 64% of all invertebrate macrofauna, with 13,757 specimens in 44 families representing 203 species. The best represented families were Spionidae, Capitellidae, Paraonidae, Cirratulidae, Maldanidae, Ampharetidae and Nephtyidae. Bah! ıa Todos Santos presented high species richness (species/station); values varied between 6 (near the harbor) and 67 species (next to Estero Punta Banda). Higher species richness values (48 species to 67/station) were located in the southern section of the bay. Abundances (individuals/station) were generally high (120-1434) except for some coastal stations. Nearly onethird of the stations presented H 0 values higher than 4.00. Diversity (H 0 ) values ranged from 2.06 to 4.80; higher diversity values were found in the southern section of the bay.
Continental Shelf Research, 2011
This study presents a comprehensive assessment of the diversity and spatial distribution of the soft-bottom benthic macrofauna communities along the Portuguese continental shelf and discusses the relationship between biological and environmental data. A total of 145 sites were sampled using a 0.1 m 2 Smith-McIntyre grab covering the whole west and south coast of Portugal, at depths ranging 13 and 195 m. More than 30,000 specimens were identified corresponding to 737 taxa, mostly annelids (43% of the total taxa). The most frequent species were Ampharete finmarchica, Ampelisca sp. and Lumbrineris lusitanica while the most abundant were Mediomastus fragilis, Polygordius appendiculatus and Ampharete finmarchica. Abundance ranged between 7 and 1307 specimens per 0.1 m 2 and alpha diversity reached a maximum of 96 taxa per 0.1 m 2 . Gravel sediments, and shallow and sheltered areas presented higher diversity values than mud sediments and deeper sites. Six major benthic assemblages were identified: (a) Coarse sediments, mostly located on the western shelf, with Protodorvillea kefersteini, Pisione remota, Angulus pygmaeus and several other interstitial species; (b) near shore fine sands with Magelona johnstoni, Urothoe pulchella and Angulus fabula; (c) Abra alba community in northwestern deep muddy sands; (d) Southwestern very deep muddy sands characterized by Galathowenia oculata, Lumbrinerides amoureuxi and other burrowers and tubicolous polychaetes; (e) Euchone rubrocincta, Nematonereis unicornis and other warmer water species in muddy sands of the southern and sheltered shelf; and (f) muds dominated by Sternaspis scutata, Heteromastus filiformis and Psammogammarus caecus. Sediment grain-size, organic matter, depth and hydrodynamic regime were the variables best related to the macrofauna distribution patterns, highlighting the transitional characteristics of this northeastern Atlantic area, where northern and subtropical faunas can coexist.