Heterotrophic microbial communities on the water-sediment boundary in the Kara Sea

The qualitative and quantitative characteristics of the heterotrophic microbial communities (bacteria, flagellates, and ciliates) in the thin water-sediment layer in the Kara Sea are analyzed. The bacterial abundance correlated with the concentration of organic matter, whereas their size depended on the abundance of heterotrophic flagellates. The number of species of heterotrophic flagellates increased with the increase in the bacterial number. A positive relationship between the bacterial abundance and the ration of heterotrophic flagellates was observed at the offshore stations, probably due to the grazing pressure. The density of the ciliates on the soft silty and sandy-silty sediments was extremely low. The share of upstream filter feeding ciliate species increased with the increase in the abundance of the flagellates, probably due to the shift to less selective feeding strategies at higher values of the food concentrations. The classification of the heterotrophic microbial communities in the surface sediment layer has revealed two distinct types of the communities. The river communities are rich in species and are characterized by the high abundance of microorganisms. They are gradually replaced by marine communities at the salinity of 9%.     

Effect of observation method on the perception of community structure and water quality in a brackish water ecosystem

The EU Water Framework Directive is a Community legislative instrument in the field of environmental protection that establishes a common framework for keeping water quality at a favourable level. To implement the directive, classification systems need to be established that allow detection of human impacts at early stages and, thus, more effective management of coastal communities. Due to the spatial variability of communities, however, the results of any assessment are highly dependent on the selection of data. In this study we identified local spatial scales in which variability of macrophyte communities was maximised, quantified links between observed patterns of sediment types and communities and estimated how selection criteria impacted the outcome of the assessment of indicator class value in four different communities of the Northern Baltic Sea. The main findings of the study were that: (i) there were no clear local spatial scales in which the variability of benthic communities was maximised; (ii) hard-bottom communities were better predicted by the spatial arrangement of sediment characteristics than soft-bottom communities; (iii) the selection of method had no effect on the estimates of macrophyte cover and indicator class; but (iv) method impacted independently of habitat type on error estimates of macrophyte cover and indicator class. To conclude, in such homogeneous and low diversity macrophyte communities it is preferable to use methods that result in lower error estimates of algal coverage and, thus, result in lower uncertainties of estimates in the water quality class.     

Socio-economic drivers and indicators for artisanal coastal fisheries in Pacific island countries and territories and their use for fisheries management strategies

This is the first regional study of artisanal fisheries in Pacific Island countries and territories that demonstrated that the future of the region's artisanal fishery sector and the livelihood of coastal communities will be highly dependent on alternative subsistence and income sources, which are necessary to reduce fishing pressure to a sustainable level to maintain ecosystem services and food security. The overall objective of this study was to identify socio-economic indicators and drivers to improve the understanding of the dynamics between socio-economic conditions and current exploitation levels of finfish and invertebrates of coastal communities in 17 Pacific Island countries and territories. We showed that exploitation rates and thus possible overexploitation are not solely the consequence of a simple demographic growth process but are in fact a result of the choices people have. Our results confirmed a close relationship between resource exploitation rates and economic development at the national level and the availability of alternative income opportunities at the community level. Multivariate analysis results suggest that communities in countries with somewhat unfavourable conditions and limited access to alternatives and fishing households in communities with overall favourable economic conditions are at highest vulnerability as they have the highest dependence on coastal fisheries resources. Alternative economic opportunities at the national scale and availability of alternative income at the community level vary significantly between cultural groups. Based on our results, the development of management strategies with realistic expectations of ensuring livelihood of coastal communities and sustainable resource use in Pacific Island countries and territories requires a hierarchical and integral approach. Major drivers identified at the regional, cultural and local levels should be used to identify priorities, to assess overall advantages and limitations at the different levels as well as the vulnerability of communities targeted, and to develop strategies accordingly.     

Macrobenthic infaunal communities associated with deep‐sea hydrocarbon seeps in the northern Gulf of Mexico

There are thousands of seeps in the deep ocean worldwide; however, many questions remain about their contributions to global biodiversity and the surrounding deep‐sea environment. In addition to being globally distributed, seeps provide several benefits to humans such as unique habitats, organisms with novel genes, and carbon regulation. The purpose of this study is to determine whether there are unique seep macrobenthic assemblages, by comparing seep and nonseep environments, different seep habitats, and seeps at different depths and locations. Infaunal community composition, diversity, and abundance were examined between seep and nonseep background environments and among three seep habitats (i.e., microbial mats, tubeworms, and soft‐bottom seeps). Abundances were higher at seep sites compared to background areas. Abundance and diversity also differed among microbial mat, tubeworm, and soft‐bottom seep habitats. Although seeps contained different macrobenthic assemblages than nonseep areas, infaunal communities were also generally unique for each seep. Variability was 75% greater within communities near seeps compared to communities in background areas. Thus, high variability in community structure characterized seep communities rather than specific taxa. The lack of similarity among seep sites supports the idea that there are no specific infauna that can be used as indicators of seepage throughout the northern Gulf of Mexico, at least at higher taxonomic levels.     

Recruitment of benthic organisms onto a planned artificial reef: shifts in community structure one decade post-deployment

Most artificial reef (AR) studies have examined the early colonization stages of benthic communities, while only a few have monitored the development of AR communities beyond the initial successional phases and evaluated the time scale needed for such development. In addition, despite the proliferation of AR studies, comparative studies between artificial and natural reefs (NRs) are scarce. We present here the monitoring results of initial (1-2 year) and progressed (10 year) stages of the developing benthic communities of a purpose-planned AR submerged at Eilat, Israel (Red Sea), and compare them to its adjacent NR. Visual surveys of macro-invertebrates were conducted on the initial stages and coral communities were characterized at the progressed stage, using belt transects. The results demonstrate a distinct shift in species composition of the AR communities along the monitoring periods: from a soft coral dominated community, comprised mainly of Dendronephthya hemprichi, in initial developmental stages of up to two years post-deployment, to a community dominated by the sponge Crella cyatophora at year 10. Distinct differences in coral species count, living cover and diversity were found between the AR and its neighboring NR. We estimate the time frame required to develop a progressed diverse AR community to be well over a decade, even in tropical ecosystems. The factors shaping the species composition of purpose-designed ARs in a coral reef environment, including structural design, spatial orientation, depth and age, are discussed.     

Foraminifer communities of the atlantic continental margin of Europe

Based on an analysis of the structures of the populations of benthic foraminifers at 639 stations located on the Atlantic continental margin of Europe, 33 communities were distinguished and mapped with respect to the abundance of the dominating species. The habitats of the communities are formed under the influence of environmental factors, which depend on the latitudinal and bathymetric zonations of the basin, the currents, the near-bottom upwellings, coastal water runoff, and topography of the boundaries between water masses. The communities recognized are confined to certain water masses, which helps one to trace the boundaries between the water masses and the regions of near-bottom upwellings.     

Spatial and temporal patterns of benthic macrofaunal communities on the deep continental margin in the Gulf of Guinea

Density, taxonomic composition at higher taxon level and vertical distribution of benthic macrofaunal communities and sediment characteristics (pore water, nitrogen, organic carbon, sulfur, C/N ratio, n-alcohol biomarkers) were examined at three deep sites on the Congo–Gabon continental margin. This study was part of the multidisciplinary BIOZAIRE project that aimed at studying the deep benthic ecosystems in the Gulf of Guinea. Sampling of macrofaunal communities and of sediment was conducted during three cruises (January 2001, December 2001 and December 2003) at two downslope sites (4000 m depth), one located near the Congo submarine channel (15 km in the south) and the other one far from the channel (150 km in the South). The third area located 8 km north of the Congo channel in the surroundings of a giant pockmark at 3160 m depth was sampled during one cruise in December 2003.At these three locations the macrofaunal communities presented relatively high densities (327–987 ind. 0.25 m⁻²) compared with macrofaunal communities at similar depths; that is due to high levels of food input related to the Congo river and submarine system activities that affect the whole study area. The communities were different from each other in terms of taxonomic composition at higher taxon level (phylum, class, order for all the groups except for the polychaetes classified into families). The polychaetes dominated the communities and were responsible for the increase in densities observed at both deep sites (4000 m) between January 2001 and December 2003 whereas the tanaidaceans, the isopods and the bivalves were the other most abundant taxa responsible for the spatial differences between these sites. The community at 3150 m differed from the two deep communities by higher abundances in bivalves, nemerteans and holothuroids. The composition of the polychaete community also differed among sites.In the vicinity of the Congo channel, the expected positive effect of the additional organic matter transported through the turbiditic currents on to the surrounding benthic communities was not observed, as the increase in densities during the study period was higher at the site located away from the Congo channel than near the channel (80% vs 30%). That may be due to the low food value of the organic matter of terrestrial origin carried through the turbidites, and/or to the disturbance caused by these turbidites. Conversely, far from the channel the macrofaunal communities benefit from organic matter of higher energetic value originating mainly from marine sources, but also from continental sources, carried by the Congo plume or by near-bed currents across or along the continental slope. Spatial and temporal variability in trophic and physical characteristics of the sediment habitat at both deep sites also affected the vertical distribution of the macrofaunal communities.The activities of the very active Congo system structure the deep macrofaunal communities on a large area in terms of densities, composition and vertical distribution. The food input is enhanced at regional scale as well as the heterogeneity of the sediment characteristics, mainly in terms of organic matter quality (marine vs terrigenous). In turn, the densities are enhanced as well as the regional diversity of the macrofaunal communities in terms of taxonomic composition and distribution.     

Limited differences among habitats in deep‐sea macro‐infaunal communities off New Zealand: implications for their vulnerability to anthropogenic disturbance

The spread of human activities into the deep sea may pose a high risk to benthic communities and affect ecosystem integrity. The deep sea is characterized by physical and biological heterogeneity and different habitat types are likely to differ in their vulnerability to anthropogenic impacts. However, across‐habitat comparisons are rare, and no comprehensive ecological risk assessment has yet been developed. To address this gap in our knowledge, we compared macro‐infaunal community structure in four habitats (slope, canyons, seamounts and methane seeps) at depths between 700 and 1500 m in the Hikurangi Margin and Bay of Plenty regions off New Zealand. The most striking contrast in community structure was between the two study regions, due to an order of magnitude difference in macro‐infaunal abundance that we believe was caused by differences in surface productivity and food availability at the sea bed. We found differences in structural and functional attributes of macro‐infaunal communities among some habitats in the Hikurangi Margin (slope, canyon and seep), but not in the Bay of Plenty. We posit that differences between canyon and slope communities on the Hikurangi Margin are due to enhanced food availability inside canyons compared with adjacent slope habitats. Seep communities were characterized by elevated abundance of both symbiont‐bearing and heterotrophic taxa, and were the most distinct, and variable, among the habitats that we considered on the Hikurangi Margin. Communities of seamounts were not distinct from slope or canyon communities on the Hikurangi Margin, probably reflecting similar environmental conditions in these habitats. The communities of deep‐sea canyon and seep habitats on the Hikurangi Margin were sufficiently dissimilar from each other and from slope habitats to warrant separate management consideration. By contrast, the low dissimilarity between communities of canyon and slope habitats in the Bay of Plenty suggests that habitat‐based management is not required in this region, for macro‐infauna at least. Although the two study regions share similar species pools, populations of the Hikurangi Margin region may be less vulnerable than the sparser populations of the Bay of Plenty due to the higher availability of potential colonizers and faster population growth. Thus regions, and habitats in some regions, should be subject to separate ecological risk assessment to help identify the key risks and consequences of human activities, and to inform options for reducing or mitigating impacts.     

Identifying fisheries dependent communities in EU coastal areas

The importance of local communities relying on fisheries is constantly emphasised in the European Union's Common Fishery Policy. Previous studies have analysed fishery employment for the entire EU based on statistical figures aggregated by administrative units at the regional or provincial level. This paper adopts a geographical approach to identify EU coastal communities relying on fisheries using accessibility analysis, principles at the basis of gravity models and disaggregated population and employment statistics. The dependency on fisheries is calculated comparing estimated employment from fisheries at each port with general employment in the areas of accessibility surrounding the port. By considering spatially disaggregated statistics the importance of fishing activities for specific local communities emerges more clearly in respect of previous studies. The map of fisheries dependent coastal communities identifies in 2010, 388 communities, out of 1697, with dependency ratios above 1%. Around 54% of total fishery employment is estimated in these areas. In terms of policy support, identifying and mapping these local fishing coastal communities is of key importance considering the strong priority assigned by the new European Union's Common Fishery Policy to fishery management at the regional level.     

Cold seeps of the deep Gulf of Mexico: Community structure and biogeographic comparisons to Atlantic equatorial belt seep communities

Quantitative collections of tubeworm- and mussel-associated communities were obtained from 3 cold seep sites in the deep Gulf of Mexico: in Atwater Valley at 1890 m depth, in Alaminos Canyon at 2200 m depth, and from the Florida Escarpment at 3300 m depth. A total of 50 taxa of macro- and megafauna were collected including 2 species of siboglinid tubeworms and 3 species of bathymodiolin mussels. In general, the highest degree of similarity was between communities collected from the same site. Most of the dominant families at the well-characterized upper Louisiana slope seep sites of the Gulf of Mexico were present at the deep sites as well; however, there was little overlap at the species level between the upper and lower slope communities. One major difference in community structure between the upper and lower slope seeps was the dominance of the ophiuroid Ophioctenella acies in the deeper communities. The transition between upper and lower slope communities appears to occur between 1300 and 1700 m based on the number of shared species with the Barbados seeps at either end of this depth range. Seep communities of the deep Gulf of Mexico were more similar to the Barbados Accretionary Prism seep communities than they were to either the upper slope Gulf of Mexico or Blake Ridge communities based on numbers of shared species and Bray–Curtis similarity values among sites. The presence of shared species among these sites suggests that there is ongoing or recent exchange among these areas. An analysis of bathymodioline mussel phylogeography that includes new collections from the west coast of Africa is presented. This analysis also suggests recent exchange across the Atlantic equatorial belt from the Gulf of Mexico to the seeps of the West Nigerian margin.     

Influence of disturbance and nutrient enrichment on early successional fouling communities in an oligotrophic marine system

Disturbance and productivity are often cited as the main factors determining temporal and spatial patterns in species distribution and the diversity of communities. A field experiment was conducted to test the role of these factors in the structuring of early successional fouling communities in a nutrient limited system at the south coast of Madeira Island. Macro‐benthic sessile communities, established on artificial settlement substrata, were manipulated and surveyed over a 9‐week period. We applied mechanical disturbances of four different frequencies crossed with three levels of inorganic nutrient enrichment. Fertilization enhanced community diversity by favouring the establishment and growth of macroalgae. Disturbance reduced diversity by eliminating species – but only at the highest nutrient level. This is explained by a multiple‐stressor model; species most sensitive to nutrient deficiency (only present in the highest enrichment treatment) were simultaneously the most sensitive to disturbance.     

Deep-sea habitat heterogeneity influence on meiofaunal communities in the Gulf of Guinea

To estimate the degree of spatial heterogeneity of benthic deep-sea communities, we carried out a multiple-scale (from m's to 200 km) investigation in the Congo-Angola margins (Equatorial West African margin, 3150–4800 m) in which we examined the metazoan meiofauna at a variety of habitats along the Congo Channel system and in the associated cold seep. We investigate the structure, density, vertical distribution patterns in the sediment and biomass of meiofaunal communities in the Gulf of Guinea and how they are controlled by hydrologic and biogeochemical processes. The meiofaunal communities in the Gulf of Guinea were shaped by heterogeneous conditions on the margin, and reflect the multiple-scale spatial variability that corresponds with the different identified habitats. The two control sites, located at >100 km away from the canyon, were inhabited by very dense and the most diverse meiobenthic communities. Similar meiobenthic communities inhabited the transition zone between the canyon and the cold seep. Sites located along the Congo Channel were obviously affected by the local high-velocity bottom currents and unstable sedimentary conditions in this active submarine system. Extremely low meiobenthic densities and very low proportions in the most surficial sediment layers provided evidence for recently highly disturbed sediments at these sites. The remote operated vehicle (ROV) Victor 6000 provided images of the cold seep, showing a patchy distribution of several types of patchy distributed megafaunal communities dominated by three key symbiotic taxa (Mytilidae, Vesicomyidae and Siboglinidae). These cold seep sediments were colonised by a unique meiobenthic community, characterised by a high small-scale (m's) patchiness, low species richness and the prominent dominance of two large-sized nematode species: Sabatieria mortenseni, which is a cosmopolitan nematode known from littoral habitats, and an undescribed Desmodora species. The high individual body weight of S. mortenseni and its dominance at the cold seep site resulted in a significantly higher nematode biomass at the seep compared to the surrounding sites. In addition, the vertical nematode profiles, with maximum proportions in subsurficial layers, points to a chemosynthesis-based meiobenthic community in this cold seep, in contrast to the phytodetritus-based communities at the control sites and at the transition zone.     

CRYPTOFAUNAL COMMUNITIES OF CORAL REEFS

INTRODUCTION Cryptofaunal communities consist of the animals and plants living within dead coral.As a very large part of a coral reef is composed of dead coral,the biomasses of crypto-faunal communities on a reef must be significant.And as many of the cryptofaunal animalsreproduce at regular intervals,rates of turnover of the community are also high and thusare major contributors to the productivity of coral reefs.Grassle(1973)collected a 4.7     

Patterns in subtidal seaweed communities on coral-dominated reefs at Sodwana Bay on the KwaZulu-Natal coast,South Africa

Subtidal seaweed communities of the northern coast of KwaZulu-Natal (KZN) have not been studied before. At Sodwana Bay, we tested the hypotheses that the seaweed communities would (1) differ floristically with depth, (2) be more species-rich in shallower water, (3) show similar biomasses within the depth range sampled and (4) be affected (biomass and/or species composition) by sand. Samples were collected (using SCUBA) from reefs ('sites') at depths of about 1m, 7m, 10m, 15m and 26m. Each sample comprised all macroscopic (non-crustose) seaweeds within a 25cm × 25cm quadrat (five quadrats per depth). Environmental factors, including percentage sand cover and depth, were recorded. The seaweed communities were mainly compact turfs; a total of 82 Rhodophyta, 14 Chlorophyta and eight Phaeophyta were recorded. Ordination (canonical correspondence analysis) and classification (Twinspan) of the data showed clear differences in the floristic composition (either as species biomass or presence/absence) with depth, mainly between shallow subtidal communities (0.5–1.0m depth) and those at intermediate depths (5.5–15.0m), followed by the deepest communities (25.7–29.0m) and those at intermediate depths. The shallow samples showed the greatest species diversity. Total seaweed biomass decreased significantly with depth and percentage bare (seaweed-free) substratum increased significantly with depth, possibly because of lower wave action, light penetration, or different grazing patterns. Sand (as percentage sand cover) also affected seaweed community composition, but this showed no pattern with depth. The algal communities on these reefs at Sodwana Bay showed exceptional α-diversity, with 104 taxa (>20% of the recorded KZN flora) occurring in the total sample area of only 1.56m². The seaweed communities of northern KZN are structurally and floristically similar to those of other tropical coral reefs around the world.     

Mass mortality and recolonization of Pyura stolonifera (Heller) on the south coast of South Africa

The fauna and flora of two sublittoral communities situated in close proximity on the west coast of South Africa are described and shown to be radically different, despite the fact that both experience similar physical conditions. One of these communities, at Marcus Island, has prolific beds of the black mussel Choromytilus meridionalis (35 954 g wet weight·m^?2) accompanied by a large number of other species, notably sea urchins, holothurians, brittle stars, whelks and barnacles. In contrast, the other site, Malgas Island, is dominated by a large population of rock lobsters Jasus lalandii together with a dense seaweed flora (3 866 and 4 402 g wet weight·m^?2 respectively). The numbers of species are similar at both sites (102 at Malgas Island and 107 at Marcus Island) but only 34 per cent are common to both localities. Although preliminary research indicates that the two sites have fairly similar physical conditions and bottom topography, they maintained their contrasting communities for the whole research period (1983–1986) and have probably done so for at least nine years, suggesting that they represent two stable alternative states of the same ecosystem. In the absence of rock lobsters at Marcus Island, wave action and inter/intraspecific competition are the main forces structuring the benthic community. Stability is maintained here by the resilience and rapid recovery of the mussel population after disturbance by storms. Where rock lobsters are abundant, as at Malgas Island, intense predation pressure is the main force controlling the structure of the benthos, and it is continually maintained because the rock lobsters are resistant to the effect of storms. Therefore, the presence or absence of high densities of rock lobsters is fundamental to the maintenance of these two contrasting communities.     

Effects of different types of mechanical disturbances on a charophyte dominated macrophyte community

Charophytes are unique and endangered macroalgae. Mechanical stress is known to damage charophyte communities, however, virtually nothing is known how such disturbance affect seasonal succession and recovery of charophyte communities. We examined the response of a shallow water charophyte community to different types and timing of disturbances by conducting seasonal in situ field experiment in a brackish water ecosystem. The disturbances associated with mechanical removal of vegetation or sediment had the largest impact on the charophyte community. Disturbances that only partly damaged the plants had minor effects and communities were characterized by fast recovery. The timing of disturbance had significant effects on the charophyte community with stronger effects when disturbed at the early stage compared to mid-stage of seasonal succession.     

Protected nearshore shallow and deep subtidal rocky reef communities differ in their trophic diversity but not their nutritional condition

Large physical changes that alter reef macrobenthos and fish assemblages occur with increasing depth, so the biological processes that regulate communities at different depths are expected to diverge. We used analyses of stable isotopes (δ13C and δ15N) and fatty acids to establish whether shallow (11–25 m) and deep (45–75 m) warm-temperate reef communities within a South African marine protected area differ in their trophic organisation and nutritional condition. We found evidence of enhanced nutritional condition in plankton from the deeper reef as compared with the shallow reef based on the essential fatty acid content, but this effect was generally not observed in the macrobenthos or the fish communities. Community-based indices derived from the stable isotope data indicated that the shallow-reef community had significantly greater niche diversification (greater diversity of carbon sources at the base of the food web) and more niche space occupied than the deep-reef community. One obvious difference in available carbon sources between reef communities was the absence of benthic primary production on the deep reef, where light is limiting. Our results highlight that the decreased trophic diversity, and to an extent functional redundancy, associated with the simplification of food webs at depth may translate into greater vulnerability of deep reefs to disturbance.     

Peripheral communities of the Eastern Lau Spreading Center and Valu Fa Ridge: community composition,temporal change and comparison to near‐vent communities

Western Pacific hydrothermal vents will soon be subjected to deep‐sea mining and peripheral sites are considered the most practical targets. The limited information on community dynamics and temporal change in these communities makes it difficult to anticipate the impact of mining activities and recovery trajectories. We studied community composition of peripheral communities along a cline in hydrothermal chemistry on the Eastern Lau Spreading Center and Valu Fa Ridge (ELSC‐VFR) and also studied patterns of temporal change. Peripheral communities located in the northern vent fields of the ELSC‐VFR are significantly different from those in the southern vent fields. Higher abundances of zoanthids and anemones were found in northern peripheral sites and the symbiont‐containing mussel Bathymodiolus brevior, brisingid seastars and polynoids were only present in the northern peripheral sites. By contrast, certain faunal groups were seen only in the southern peripheral sites, such as lollipop sponges, pycnogonids and ophiuroids. Taxonomic richness of the peripheral communities was similar to that of active vent communities, due to the presence of non‐vent endemic species that balanced the absence of species found in areas of active venting. The communities present at waning active sites resemble those of peripheral sites, indicating that peripheral species can colonize previously active vent sites in addition to settling in the periphery of areas of venting. Growth and mortality were observed in a number of the normally slow‐growing cladorhizid stick sponges, indicating that these animals may exhibit life history strategies in the vicinity of vents that differ from those previously recorded. A novel facultative association between polynoids and anemones is proposed based on their correlated distributions.     

Spatial variability of the surf zone fish and macroinvertebrate community within dissipative sandy beaches in Oregon,USA

Habitat heterogeneity can influence biological communities by providing a diversity of areas that can be occupied by different species. Sandy beach surf zones are often considered homogenous environments; however, sand bars moved by currents and waves can produce trench‐like shapes or troughs that provide heterogeneity. The influence of habitat heterogeneity produced by sand movement is unclear despite the fact that surf zones are an important habitat for larval and juvenile fish and macrocrustaceans. To determine if, and how, the fish and macroinvertebrate communities present in trough and non‐trough or flat areas of Oregon surf zones differ, we compared species assemblages in both areas at three beaches adjacent to estuary mouths over 2 years. Troughs had different communities compared with flat areas, with higher total catch (mean ± SD = 123.2 ± 122.1 versus 43.6 ± 44.5 individuals × 100 m^?2) and taxon richness (6.7 ± 2.7 versus 4.0 ± 2.3 taxa); these differences were potentially due to water movement, prey availability and sediment size. The fish and macroinvertebrate communities did not vary between years but there were significant differences among beaches, with the most distinct community present at the only beach adjacent to an estuary without a jetty at its mouth, which was possibly due to higher species movement between the surf zones and estuary. Fish and macrocrustacean surf zone communities varied spatially within and among beaches in relation to habitat heterogeneity provided by sand movement and, potentially, the influence of adjacent habitats.