Polychaete Feeding Guilds Research Articles

Community Structure and Trophic Ecology of Fish Assemblages in an Ephemeral Polychaete Reef on a Tropical Mudflat

Information regarding the vagile fish fauna and their use of rare polychaete reefs as habitat or feeding area is almost unheard of in the tropics. Of great interest is whether the construction of such biogenic reefs in an otherwise featureless habitat such as a mudflat increases structural complexity thereby enhancing fish abundance and ecological functioning. The Jeram polychaete reef (Straits of Malacca) is unique and recurrent; on the mudflat, it emerges, grows, and decimates within a year. We tested the hypothesis that the enhanced reef resources (prey) modify the reef ichthyofauna in terms of community structure and trophodynamics. The largely juvenile fish that visited the reef totaled 69 species from a 9-month study. Although sharing 57 common species, the reef fish assemblages had less species and diversity than the mudflat (90 species) and also lower abundance and biomass. Temporal variability in the reef’s fish community structure appeared to be tied to the reef dynamics, food availability, and environment. Stable isotope (C and N) results suggest a food web of five trophic levels emanating from phytoplankton and benthic diatoms as basal sources, similar to the mudflat. The enhanced prey resources modified the ichthyofauna, but did not impact reef fish trophodynamics in terms of feeding guild, trophic level, and dietary carbon. Although the polychaete feeding guild was distinct in the reef, most reef fishes as well as mudflat fishes were generalist predators. The reef supports local fisheries, functioning as a feeding and habitat area for 58 fish species of commercial importance.

Spatio-temporal variability in macrobenthic communities and trophic structure of a tropical estuary and its adjacent coastal waters.

Spatio-temporal distribution of the macrobenthic community (> 500μm) and the trophic ecology of polychaetes were studied for a year in the Cochin estuary (CE) and its adjacent coastal waters. A profound influence of the southwest monsoon (SWM) was evident in the CE, a tropical monsoonal estuary, during the present study. The sediment texture and macrobenthic density exhibited a pronounced spatial variation in the estuary, while in the coastal waters temporal changes were more prominent. Polychaetes formed the dominant taxa in terms of density and diversity in the estuary (53 species belonging to 25 families) as well as in the adjacent coastal waters (39 species belonging to 20 families). The polychaete species Diopatra neapolitana dominated during nonmonsoonal periods was found to be replaced by the higher abundance of Pisione sp. in the CE during the monsoon period. On the other hand, in the coastal waters, Cossura coasta, the dominant species during the pre-monsoon period, was replaced by the surface deposit feeder Paraprionospio pinnata during the monsoon and post-monsoon periods. The study evidenced the combined influence of sediment texture, salinity, and food availability in determining the distribution and abundance of the macrobenthic fauna in the CE and adjacent coastal waters. Feeding guild analysis and trophic importance index showed that carnivores and surface and subsurface deposit feeders were the dominant and trophically important feeding guilds in the study area. Redundancy analysis showed that the sandy substratum supported a diversified functional composition in the estuary and its adjacent coastal waters, and motile, discretely motile polychaetes and filter feeders were more associated with the sandy substratum. Results of the present study revealed that the seasonally fluctuating polychaete community structure in the study area was predominantly controlled by their diversified feeding habits and the ecological descriptors of the polychaete feeding guilds were linked primarily to the substratum type and food availability.

The polychaete feeding guild composition in the Sishili Bay, the northern Yellow Sea, China

In this research, the feeding guild composition of the polychaete community was described and analysed in the northern Yellow Sea, China. The polychaete feeding guilds also showed a distinct seasonal abundance fluctuation that was similar to that observed for macrofauna. Burrowers were the most predominant feeding guild, whereas filter feeders and herbivores only constituted a negligible proportion of the total abundance. A Spearman rank correlation was performed to analyse the relationships between the feeding guilds and the environmental parameters. Surface deposit feeders and carnivores appeared to be vulnerable to variations of environmental conditions. However, burrowers and filter feeders were not susceptible to the natural or anthropogenic disturbances, with grain size determined to be the only conclusive factor. These results revealed that the feeding guild of polychaetes showed significant spatial and temporal changes, and spatial heterogeneity was a stronger predictor than temporal variation. The feeding guilds of polychaetes can be applied alone to discern the environmental change, which would be faster and more cost-effective with best equilibrium between the precision of the results and a decrease in taxonomic effort. Furthermore, bimonthly sampling was proved to be unessential and reduction of the sampling frequency was necessary to save expense and effort.

Diet of worms emended: an update of polychaete feeding guilds.

Polychaetes are common in most marine habitats and dominate many infaunal communities. Functional guild classification based on taxonomic identity and morphology has linked community structure to ecological function. The functional guilds now include osmotrophic siboglinids as well as sipunculans, echiurans, and myzostomes, which molecular genetic analyses have placed within Annelida. Advances in understanding of encounter mechanisms explicitly relate motility to feeding mode. New analyses of burrowing mechanics explain the prevalence of bilateral symmetry and blur the boundary between surface and subsurface feeding. The dichotomy between microphagous deposit and suspension feeders and macrophagous carnivores, herbivores, and omnivores is further supported by divergent digestive strategies. Deposit feeding appears to be limited largely to worms longer than 1 cm, with juveniles and small worms in general restricted to ingesting highly digestible organic material and larger, rich food items, blurring the macrophage-microphage dichotomy that applies well to larger worms.

Feeding guild composition of shelf macrobenthic polychaetes of southeast coast of India

This study compares the feeding guild composition of macrobenthic (infaunal) polychaetes from two different transects (Cheyyur and Singarayakonda) situated in the continental shelf region of southeast coast of India. The polychaetes collected from these transects were identified using standard manuals [Fauvel P. 1953. The fauna of India including Pakistan, Ceylon, Burma and Malaya: Annelida, Polychaeta. Allahabad: The Indian Press Ltd; 507 p.; Day JH. 1967. A monograph of the polychaeta of southern Africa. London: British Museum (Natural History Museum) Publication; 878 p.]. The total number of species recorded from the study area was 75 belonging to 54 genera and 29 families. These species were categorized into various feeding types following Fauchald and Jumars [Fauchald K, Jumars PA. 1979. The diet of worms: a study of polychaete feeding guilds. Oceanography and Marine Biology: Annual Review 17: 193–284] and confirmed after examination of mouthparts. Among these, 34 species (45.3%) were found to be sur...

Complex depth-related patterns in taxonomic and functional diversity of polychaetes in the Gulf of Mexico

Patterns of taxonomic and functional diversity in polychaete assemblages were examined in the deep northern Gulf of Mexico, including the first analysis of polychaete feeding guild distribution. An analysis of samples from a total of 51 stations located along 7 transects plus additional nearby sites, indicated that density decreased exponentially with depth, with the central locations having higher densities than the eastern and western regions. Alpha diversity was also highest at the central stations associated with the Mississippi trough. The samples can be grouped into three significant clusters based on thirty percent similarity of species composition. BIO-ENV indicated depth, sediment particle size, and export POC were most important variables explaining distributions. The diversity of polychaete feeding guilds was high in the Mississippi trough, upper and mid-slope regions but declined to a few guilds on the Sigsbee abyssal plain. Combining feeding guild analysis with traditional analysis of species diversity contributes to a clearer understanding of trophic diversity in deep-sea benthic assemblages.

Environmental effects on the structure of polychaete feeding guilds on the beaches of Sepetiba Bay, south-eastern Brazil

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.

Is polychaete diversity in the deep sublittoral of an Antarctic fiord related to habitat complexity?

Is polychaete diversity in the deep sublittoral of an Antarctic fiord related to habitat complexity?Seventy-six species of Polychaeta were found in 19 quantitative samples collected in the deep sublittoral (200-500 m) of Admiralty Bay (South Shetlands). Three assemblages were distinguished by similarity analysis (clustering, nMDS). The soft bottom in depths from 200 to 300m was strongly dominated byMaldane sarsi antarcticaand had very low species richness and diversity. The second assemblage was distinguished in the areas of the sea floor in the same depth range but with aggregations of Ascidiacea and Bryozoa. It was again characterized by high abundance ofMaldane sarsi antarctica, but showed significantly higher species richness and diversity. Diversity of polychaete feeding guilds was also high in these areas. This pattern was probably associated with an increased habitat complexity due to the presence of dense aggregations of large suspension feeders. High species richness and diversity was also noted in the third assemblage, associated with the deepest sublittoral (400-500 m) of Admiralty Bay. This is the area characterized by very stable environmental conditions, where the assemblage was dominated byTharyx cincinnatus, Sternaspissp.,Maldane sarsi antarctica, andAsychis amphiglypta.

Distribution of polychaete feeding guilds in sedimentary environments of the Campeche Bank, Southern Gulf of Mexico

The aim of this study was to analyze the trophic structure of the polychaete assemblages found in the Campeche Bank, southern Gulf of Mexico and to examine the effect of the sediment composition on the spatial distribution of the feeding guilds. In all, 2,662 organisms belonging to 160 species and 16 feeding guilds were identified. Filter-feeders (Fabricinuda trilobata and Bispira melanostigma) dominated. Five groups of stations were defined based on feeding guilds: one, in the southwest, characterized by motile jawed burrowers (17.14% contribution); the second, from the southeast to the northwest, characterized by seven guilds (45.25%), mainly filter-feeders and surface deposit-feeders; the third, in the southwest, characterized by three guilds (42.13%), mainly discretely motile tentaculate filter-feeders and motile unarmed burrowers; group four, in the east, was characterized by sessile tentaculate filter-feeders (63.68%); and group five, in the center and to the north, was characterized by four guilds (53.69%), mainly discretely motile tentaculate filter-feeders. The variety of feeding guilds was higher in the northwest with seven guilds, and the lowest variety was found in the east and south with only one or two guilds. Contrary to the starting hypothesis, the sediment composition was not the main factor that determined the distribution of the polychaete feeding guilds. Instead, salinity and depth were more important for the spatial arrangement of the trophic groups. The feeding guilds of polychaetes proved to be more sensitive to environmental changes than density or diversity.

Structural and functional approaches to describe polychaete assemblages: ecological implications for estuarine ecosystems

Polychaete assemblages are of special interest when studying dynamic environments such as estuaries because of their high plasticity in life strategies to cope with environmental variability. We tested the hypothesis that polychaete feeding guilds would be more related to environmental characteristics than to taxonomic composition. Polychaetes were sampled on two different occasions along three tropical estuarine systems in north-eastern Brazil. Different polychaete taxa replaced one another along the entire salinity gradient and the overall pattern from high- to low-salinity regions was from high species and feeding-guild diversities to dominance by a single species or a feeding group. We suggest that the relationships between structure and function of polychaete assemblages might provide a measure of the resilience of estuarine conditions; estuaries with a high redundancy in the trophic role of polychaetes might recover faster from disturbance and retain more natural ecological functions than those estuaries with low or no redundancy, because more species would have the capacity to expand their niches to compensate for the loss of neighbouring species. Integrative approaches allying species composition to their trophic role need to be thoroughly investigated to help understand such complex temporal and spatial organisation of benthic assemblages in estuaries.

Trophic relationships of polychaetes associated with different algal growth forms

The trophic relations of the polychaete species associated with four different algal growth forms (filamentous, fan-shaped, bush-like and encrusting) were studied in the North Aegean Sea. Samples for the spatial analysis were collected in summer with a quadrate sampler (400 cm2) at a depth range of 15–40 m. Filamentous and encrusting forms were also seasonally sampled in order to detect the temporal changes. A total of 5,494 individuals belonging to 79 species were classified to 12 feeding guilds, considering the type of food, the feeding apparatus and the motility patterns involved. Carnivores dominated, followed by herbivores and filter-feeders, among all the algal forms studied, excepting the fan-shaped form where filter-feeders prevailed mainly due to a massive recruitment of spirorbids. With respect to the abundance of the various feeding guilds, filamentous and fan-shaped forms discriminated, whereas bush-like and encrusting forms showed high similarity. The occurrence of polychaete feeding guilds among both filamentous and encrusting forms showed seasonal changes, with summer and spring samples, respectively, discriminating. The results of the trophic group analysis conformed to previous information provided by a taxon composition analysis of the dominated by the same algae communities. However, a functional study can give additional information and is thus a useful tool for the study of hard bottom communities.

Another diet of worms: the applicability of polychaete feeding guilds as a useful conceptual framework and biological variable

AbstractA fundamental question in guild studies is how to separate species into guilds. In a seminal manuscript, Fauchald & Jumars [Oceanography and Marine Biology Annual Review17 (1979) 193] summarized polychaete feeding biology and proposed a conceptual framework to test hypotheses on the sympatric occurrence of congeners with limited morphological differentiation. Twenty‐six years after this publication, few studies have tested the validity and practical functioning of this scheme of polychaete feeding guilds and then only using part of the classification. The objective of the present study was to analyze the applicability of polychaete feeding guilds to ecological and environment assessments. Two data sets from Santa Catarina Island Bay, southern Brazil, were used. The first data set deals with spatial distribution of natural polychaete assemblages along the bay. The second data set treats fauna in urbanized versus relatively pristine mangroves. Multivariate analysis showed similar patterns in sample groups formed using guilds or densities and composition data. The role of feeding guilds in benthic systems was assessed through comparison with environmental variables. The polychaete assemblage from the Bay was related to sediment type. Motile and discretely motile carnivores and herbivores with jawed probosces matched coarse sands; surface deposit feeders and filter feeders were found in fine sands; and surface and subsurface deposit feeders and carnivores, all with soft probosces matched silt and clay sediments. The data analyses in mangroves showed surface deposit feeders and filter feeders in undisturbed sites and omnivorous species in disturbed ones. The polychaete feeding guilds appear relevant to assembly rules based on resource availability, to resource partitioning and to interspecific competition.

More about taxonomic sufficiency: a case study using polychaete communities in a subtropical bay moderately affected by urban sewage

The taxonomic sufficiency approach has been proposed as a surrogate for the typical analysis of speciesabundance data, especially in conditions involving prominent pollution gradients. Here, we evaluate the use of taxonomic sufficiency with infralittoral macrobenthic data derived from samples taken in a moderate polluted subtropical environment in southeastern Brazil, analysing five taxonomic levels and including two functional levels throughout polychaete feeding guilds and trophic groups. The data were collected seasonally at nine stations and studied for two abundance data series (0.5 and 1.0 mm sieve mesh-size). The results showed a similar ordination pattern between the two sieve mesh-size, but with the 0.5 mm sieve data a different pattern was observed during austral summer. A slight loss of information was detected using genus, family, polychaete species and their feeding guilds as taxonomic/ functional units. These results together with those of the cost/ benefit ratio, suggested that the family level seemed to be sufficient to detect the impact caused by moderate pollution in this shallow-water, subtropical environment. In additional, through the use of feeding guilds, similar patterns are obtained. Correlation analysis showed that chlorophyll a, total organic matter, zinc, and chromium sediment content were the variables that best explained the biological pattern observed and not always the best correlation coefficient occurring at the species level. The feeding guild approach seems to be useful and generates interpretable results similar to those obtained with the species level of the whole macroinfauna. The results showed an important cost reduction in the sample processing, suggesting that it is possible to adopt a coarser taxonomic level monitoring program even in species-rich communities.

The Distribution of Polychaete Feeding Guilds in Organic Enriched Sediments of San Vicente Bay, Central Chile

AbstractThe benthic macroinfauna (>500 μm) of San Vicente Bay, Central Chile (36°44′S; 73°09′W) was studied at 8 sublittoral stations along a 6.5 km length transect from the San Vicente fishery harbor out to the open sea, during October 1991, January 1992 and October 1992. Structural changes of the benthic macroinfauna were evaluated a) functionally in terms of polychaete trophic guilds, and b) numerical classification and ecological ordination. Multivariate analysis was used to explore polychaete fedding guild responses to environmental variables. The principal objective of the study was to test whether changes in functional groups (within and between stations) are related to perturbation induced by anthropogenic organic enrichment, or are a consequence of natural environmental fluctuations. Trophic guilds of polychaetes associated with the sandy environment of the bay, showed a clear seasonal dominance of carnivores during the spring 1991–1992 and of surface suspension ‐ deposit feeders, sessiles or discretely motile and tentacled polychaetes (F‐SD‐SDT, see Annex) in summer 1992. This guild distribution could be due to the sediment stability and a greater niche diversification in the more sandy stations. However, there were only a few significant relationships between trophic guilds and total organic matter and silt‐clay fraction. This limits the utility of the guilds as indicators of perturbations induced by organic enrichment. Over 95% of the variation in the guild data was explained by environmental factors such as water depth, station distance from the harbor, silt‐clay, sand, grain size and organic matter content. The comparison between reported faunistic and sedimentary data and the data obtained in this study, suggests that there is an increase of the organic enrichment of the sediments in the most inner area of this embayment. However, there is no evidence of this being directly responsible for the polychaete feeding guild distribution of San Vicente Bay.

Polychaetous Annelids from the Gulf of Nicoya, Costa Rica

AbstractPolychaetous annelids from a soft bottom community (1–46 m) were sampled from the Gulf of Nicoya, Costa Rica. A total of 125 species was identified, 120 from a faunistic study throughout the gulf and 78 species from a time study at four stations. The number of species from the Gulf was not as high as in some temperate areas. Temporal differences were slight compared to station differences. Twenty dominant species indicated three descriptive patterns: 1) Species with a marked seasonal peak and stable densities thereafter; 2) Species with a moderate seasonal peak and stable densities thereafter; and 3) Species with no discernible seasonal peak. Although 10 polychaete feeding guilds were identified, species from six feeding guilds were the dominant groups. The effect of the rainy season on polychaete opportunism and feeding guilds was discussed.

The use of polychaete feeding guilds as biological variables

Polychaete feeding guilds have recently been examined as potentially useful parameters in environmental impact assessment. Densities of polychaete species from three studies in the lower Chesapeake Bay were classified into feeding guilds and correlated with water depth, median phi size and percent silt-clay of the sediment. Polychaete densities were also grouped randomly and correlated with environmental variables. For two of the three studies a feeding guild classification did not give significantly more correlations than expected from random groupings. Problems associated with using polychaete feeding guilds as composite biological variables are discussed.

A partial food web involving predatory gastropods on a Pacific fringing reef

An analysis of the feeding habits of a diverse assemblage of predatory gastropods on a Guam fringing reef, shows that seven major prey categories are eaten, namely polychaetes, sipunculans, gastropods, bivalves, crustaceans, ophiuroids, and fish. The three largest feeding groups are the polychaete feeding guild which mainly consists of species of Conus, the gastropod guild dominated by species of the Muricidae and the sipunculan guild consisting mainly of the Mitridae. There is considerable dietary overlap between members of feeding guilds, but interaction between guilds is low and accounted for by the relatively few generalist species in the community.

Diversity of soft-bottom benthos in a tropical estuary: Gulf of Nicoya, Costa Rica

The community structure of soft-bottom infauna is described for the Gulf of Nicoya, Costa Rica, Central America, with special reference to the relationship between diversity and a tropical estuary. Of the 205 species of invertebrates collected in July, 1980, polychaetes comprised 58.6% by number of species and 68.1% by number of individuals. Density ranged from zero to 8 744 m-2 with a mean of 1 269 m-2 per station, and biomass ranged from zero to 10.986 g m-2 with a mean of 2.010 g m-2. Numerical analysis indicated considerable faunal homogeneity, characterized by polychaetes. Five major polychaete feeding guilds were recognized. From measures of diversity we concluded that the soft-bottom community of the Gulf of Nicoya was not rich for a tropical estuary. Physical processes (riverine runoff and frontal systems) mainly influenced community structure and function in the lower Gulf whereas biological processes (predation) seemed to prevail in the upper Gulf.

The impact of drilling fluid and well cuttings on polychaete feeding guilds from the US northeastern continental shelf

The effect of recent drilling operations (fluid and well cuttings) on polychaete feeding guilds from the continental shelf off Atlantic City, New Jersey, was examined. Although there were some adverse effects on macrobenthos from 2160 metric tons of cuttings and mud solids discharged into the marine environment, the composition of polychaete feeding guilds remained essentially unchanged. This key trophic relationship between polychaetes and the changing environment due to the drilling operation was apparently uninterrupted. This relationship remains to be examined in other natural and perturbed habitats.