Beach Samples Research Articles

A study of carbonate beach sands from the Yucatan Peninsula, Mexico: a case study

Sedimentological, geochemical, and X-ray diffraction (XRD) analyses in addition to the determination of biogenic fraction components (BFC) were performed in mollusk shells from carbonate beach samples collected on the northern coast of the Yucatan Peninsula, Mexico. The most abundant components of the BFC were bivalves and gastropods shells, ranging from 88.1 to 99.2 % and from 0.1 to 6.0 %, respectively, followed by minor percentages of foraminifera, coral fragments, bryozoa, oolites, spicules, and ostracods. A combination of major element, trace element, and XRD techniques were performed to show how the Mg/Ca and Mg/Sr ratios determine the possibility of a recrystallization process in bivalves and gastropods, which may be attributed to early diagenetic mechanisms caused by groundwater flows, subaerial exposure, high evaporation rates, and neomorphism. The rare earth element analyses gave the average anomalies for the following ratios (Pr/Yb)PAAS and MuQ ratio > 1, (Eu/Eu*)PAAS and MuQ and (Ce/Ce*)PAAS and MuQ < 1, suggesting little incorporation of sea water in the BFC of the shells from the Yucatan beach sands. This is also supported by the flat pattern trends of bivalves and gastropods based on the normalized patterns of light rare earth element compared to heavy rare earth element concentrations. This paper is also a contribution to the methodology of analysis of carbonate sands, i.e., whole bulk composition isolation into their main biogenic components and the accumulation of major, trace, and rare earth elements deposited into their shells, initially under subaquatic marine conditions and currently exposed to subaerial coastal influences based on the allochthonous character of the shells.

Mixed assemblages of drilling predators and the problem of identity in the fossil record: A case study using the muricid gastropodEcphora

AbstractDrillholes made by naticid and muricid gastropods are frequently used in evolutionary and ecological studies because they provide direct, preservable evidence of predation. The muricidEcphorais common in many Neogene Atlantic Coastal Plain assemblages in the United States, but is frequently ignored in studies of naticid predation. We used a combination of Pliocene fossil, modern beach, and experimentally derived samples to evaluate the hypothesis thatEcphorawas an important source of drillholes in infaunal bivalve prey shared with naticids. We focused on the large, thick-shelled venerid,Mercenaria,which is commonly drilled by naticids today. Laboratory experiments, modern beach samples, and the published literature confirm that naticids preferentially drill near the umbo (significant clumping of holes), show a significant correlation between prey size and predator size (estimated by outer borehole diameter), and preferMercenaria&lt;50 mm antero-posterior width when other prey are present. Fossil samples containingEcphora(with or without other large muricids) show no drillhole site stereotypy (no significant clumping, greater variability in placement), no significant predator: prey size correlation, drilled prey shells larger than the largest modern naticids could produce in an experimental setting, and drillholes larger in diameter than those estimated for the largest Pliocene naticids, thus supporting our hypothesis. Substantial overlap in the placement of holes drilled by naticids and muricids, however, made identifying predators from drillhole position problematic. The lack of overlapping ranges of prey shell thickness between fossil and other samples precluded the use of drillhole morphology to establish predator identity (e.g., ratio of inner borehole diameter to outer borehole diameter, drillhole angle). Whereas the difficulty in determining predator identity from drillholes limits the types of analyses that can be reliably performed in mixed-predator assemblages, recognizingEcphoraas a prominent drilling predator creates the opportunity to investigate previously unrecognized questions.

Multivariate Statistical Analysis of High Background Radiation Area on the Hadhramout Coast

This work focuses on the radiometric characteristics of beach sand along the Hadhramout coast, Gulf of Aden, Yemen. Beach sands samples were collected from 27 locations. The activity concentrations of the terrestrial radionuclides 226Ra, 232Th, and 40K were determined. The results obtained provide pioneering data on the radioactivity levels in the coastal areas of Hadhramout. The radioactivity concentration of 232Th was found to be a major contributor to the enhanced level of radiation in some beaches. The radiological data were processed using one-way analysis of variance to find out the differences between the elevated and non-elevated 232Th groups of locations and multivariate statistical analysis, i.e., principal component analysis, discriminant analysis, and clustering analysis, to find similarities and correlation between the various samples and to discriminate between the two groups of locations. From the radiation hazard point of view, the outdoor annual effective dose for the region varied from 5.1 to 155.5 mSv with a mean value of 34.9 ± 31.9 mSv. The highest radiation level was found in Al-Jraf beach, where the highest absorbed dose rate of 126.8 nGyh−1 was recorded and the radiation hazard index exceeded twice the recommended limit of unity.

A comparison of microscopic and spectroscopic identification methods for analysis of microplastics in environmental samples

The analysis of microplastics in various environmental samples requires the identification of microplastics from natural materials. The identification technique lacks a standardized protocol. Herein, stereomicroscope and Fourier transform infrared spectroscope (FT-IR) identification methods for microplastics (<1mm) were compared using the same samples from the sea surface microlayer (SML) and beach sand. Fragmented microplastics were significantly (p<0.05) underestimated and fiber was significantly overestimated using the stereomicroscope both in the SML and beach samples. The total abundance by FT-IR was higher than by microscope both in the SML and beach samples, but they were not significantly (p>0.05) different. Depending on the number of samples and the microplastic size range of interest, the appropriate identification method should be determined; selecting a suitable identification method for microplastics is crucial for evaluating microplastic pollution.

Review Of Ecotoxicological Studies Of The Marine And Estuarine Environments Of The Baixada Santista (São Paulo, Brazil)

The aim of the present study was to identify, through ecotoxicological assays, the most critical areas in the Baixada Santista area by compiling scientific papers and technical reports of the state environmental agency. Sediment samples were assessed employing Tiburonella viscana, Leptocheirus plumulosus, Nitokra sp., and embryos of Lytechinus variegatus and Perna perna. Water column samples were assessed by using Vibrio fischeri and Lytechinus variegatus. A total of 217 samples were compiled. It was found that the frequency of acute toxicity was higher in integral sediment samples from the Santos Channel (70.68%) and the lowest frequency was obtained for Bertioga beach samples (15%). Sediment from the Santos and São Vicente Channels, Santos Bay and the area for the disposal of dredged material are the places most affected, whereas the beaches of Guarujá and Bertioga presented low levels of toxicity. No ecotoxicological studies were found in Mongaguá, Itanhaém or Peruíbe cities.

Assessment of the Deepwater Horizon oil spill impact on Gulf coast microbial communities

One of the major environmental concerns of the Deepwater Horizon oil spill in the Gulf of Mexico was the ecological impact of the oil that reached shorelines of the Gulf Coast. Here we investigated the impact of the oil on the microbial composition in beach samples collected in June 2010 along a heavily impacted shoreline near Grand Isle, Louisiana. Successional changes in the microbial community structure due to the oil contamination were determined by deep sequencing of 16S rRNA genes. Metatranscriptomics was used to determine expression of functional genes involved in hydrocarbon degradation processes. In addition, potential hydrocarbon-degrading Bacteria were obtained in culture. The 16S data revealed that highly contaminated samples had higher abundances of Alpha- and Gammaproteobacteria sequences. Successional changes in these classes were observed over time, during which the oil was partially degraded. The metatranscriptome data revealed that PAH, n-alkane, and toluene degradation genes were expressed in the contaminated samples, with high homology to genes from Alteromonadales, Rhodobacterales, and Pseudomonales. Notably, Marinobacter (Gammaproteobacteria) had the highest representation of expressed genes in the samples. A Marinobacter isolated from this beach was shown to have potential for transformation of hydrocarbons in incubation experiments with oil obtained from the Mississippi Canyon Block 252 (MC252) well; collected during the Deepwater Horizon spill. The combined data revealed a response of the beach microbial community to oil contaminants, including prevalence of Bacteria endowed with the functional capacity to degrade oil.

Sediment transport trends from a tropical Pacific lagoon as indicated by Homotrema rubra taphonomy: Wallis Island, Polynesia

The assessment of sediment transport pathways in carbonate settings is complicated by ecologically sourced sediment. Tracers such as foraminifera have previously been used in these settings to describe the movement of coastal sediments on spatial and temporal scales where traditional grain size methods have limited use. The present study builds on the foraminifera-based tracer method by using Homotrema rubra, a foraminifer with an attached life habit (i.e., defined provenance in the reef) to document modern sediment transport trends at Wallis Island, a tropical Pacific lagoon. At Wallis Island, Homotrema taphonomic results discriminated amongst modern reef, lagoon, and island (beach) samples. Reef samples contained high concentrations of fragments that were large (> 250 μm) and exceptionally- to well-preserved (e.g., intact chambers, red color, angularity). In general, concentrations and degree of taphonomic alteration decreased with distance landward from the reef; lagoon samples were characterized by lower concentrations of Homotrema that were smaller in size and less preserved (e.g., pink in color, no chamber structure, rounding of edges). At the greatest distance from the reef, island (beach) samples contained the lowest concentrations of Homotrema fragments that were small, well rounded and bleached. In this regard, Homotrema taphonomy is a useful indicator of the direction and forcing of sediment transport and will therefore be useful in detecting overwash deposits in tropical settings, where distinguishing event deposits from surrounding sediment is problematic.

Molecular and culture dependent characterization of endolithic bacteria in two beach sand samples and description of Rhizobium endolithicum sp. nov.

Endolithic metagenome analysis of two beach samples collected form Chilika, Odisha, India indicated rich bacterial diversity. While the metagenome analysis of sample one yielded 16S rRNA gene sequences which represent six phyla and 16 genera, sample two yielded very rich diversity representing 17 phyla and 286 genera. Six species of bacteria were isolated from the endolithic enrichments and most of them have 16S rRNA gene sequence similarity of >99 % with known taxa, except for strain JC140(T) having <97 % sequence similarity with taxa with valid names. Strain JC140(T) is Gram-stain-negative and motile. 16S rRNA gene based EzTaxon-e BLAST analysis indicated that strain JC140(T) is closely related with the type strains of Rhizobium yanglingense SH22623(T) (96.8 %), R. alkalisoli CCBAU 01393(T) (96.3 %), R. vignae CCBAU 05176(T) (96.2 %), R. mesosinicum CCBAU 25010(T) (96.1 %) and other members of the genus Rhizobium with <96 % sequence similarity. Strain JC140(T) was characterized based on polyphasic taxonomic analysis. Strain JC140(T) could tolerate up to 5 % salinity, resistant to rifampicin (10 μg) and was positive for catalase and oxidase. The major fatty acid is summed feature 8 (C18:1ω7c/C18:1ω6c) with minor amounts of C19:0 cycloω8c, C16:0, C18:0, C17:0cyclo, summed feature 2 (C14:03OH/C16:1 isoI), summed feature 3 (C16:1ω7c/C16:1ω6c) and 2-hydroxyacid of C15:0. Diphosphatidylglycerol, phosphatidylethanol-amine, phosphatidylcholine, phosphatidylglycerol, unidentified lipids (L1, 2), unidentified phospholipid (PL1-4) constitute the polar lipids of strain JC140(T). The strain has bacteriohopane derivative (BHD2), diplopterol and two unidentified hopanes (UH1, 2) as major hopanoids. Q-10 is the major quinone of strain JC140(T). Based on polyphasic taxonomic analysis, strain JC140(T) represents a species in the genus Rhizobium for which, the name R. endolithicum sp. nov. is proposed. The type strain is JC140(T) (= KCTC32077(T) = CCUG64352(T) = MTCC11723(T) = HAMBI 2447(T)).

Validation of the Enterococci indicator for bacteriological quality monitoring of beaches in Malaysia using a multivariate approach.

There is currently no established bacteriological beach quality monitoring (BQM) program in place in Malaysia. To initiate cost-effective, sustainable bacteriological BQM schemes for the ultimate goal of protecting public health, policy decision makers need to be provided robust, indigenous empirical findings that validate appropriate water quality parameters for inclusion in such monitoring programs. This is the first study that assesses the validity of enterococci as an ideal indicator for bacteriological BQM in Malaysia using a multivariate approach. Beach water and sand samples from 7 beach locations were analyzed for a total of twenty-one microbial and non-microbial water quality parameters. A multivariate approach incorporating cluster analyses (CA), principal component analyses (PCA), and factor analysis (FA) was also adopted. Apart from the weak correlations of Staphylococcus aureus with concentrations of Vibro species (r = 0.302, p = 0.037) and total coliforms (r = 0.392, p = 0.006) in seawater, no correlation existed between S. aureus concentration and other parameters. Faecal coliforms failed to correlate with any of the tested parameters. Enterococci also correlated with more quality parameters than faecal coliforms or any other indicator. Multiple linear regressions highlighted a significant, best fit model that could predict enterococci concentrations in relation to other parameters with a maximum predictive success of 69.64%. PCA/FA clearly delineated enterococci and faecal coliforms as parameters that weighed strongly for BQM while Staphylococcus aureus, faecal coliforms and enterococci weighed strongly for beach sand quality monitoring. On the whole, higher correlations of enterococci levels with other parameters than was observed for faecal coliforms suggest that the former be considered a preferred parameter of choice for BQM in Malaysia. Our findings provide meaningful evidence particularly as it relates to the correlation of Enterococci with pathogens and other non-microbial parameters. It also provides empirical data to validate the applicability of the enterococci indicator paradigm for bacteriological beach quality monitoring in Malaysia. The current study thus provides policy decision makers evidenced based approach to parameter streamlining for optimized beach sampling and sustainable bacteriological quality monitoring.

Seasonal changes in the subtidal benthic macrofauna of a mangrove coast in northern Brazil

Melo, K.R., Tagliaro, C.H. and, Beasley, C.R., 2013.Seasonal changes in the subtidal benthic macrofauna of a mangrove coastMangrove coasts in northern Brazil are subject to seasonal discharges of freshwater input from rivers and terrestrial runoff. However, little is known about the effects of freshwater discharge on the subtidal benthos in the region. Thus, three sites, each representing a different level of seasonal discharge, Canela island (low), Ajuruteua beach (medium), and the Caeté Bay (high) were sampled in the dry (October) and wet (April/May) seasons of 2007 and 2008, respectively. Sampling was carried out using a Petersen grab and a bottom dredge (total n=74). Additional replicas (n=12) were obtained by grab for sediment analyses. Salinity and turbidity of the bottom waters, and percentage of silt/clay in the sediment were also measured. Benthic macrofauna and environmental data were analyzed using uni- and multivariate techniques. A total of 661 individuals were distributed among 47 taxa of which polychaetes and crustaceans dominated at all three sites. No significant differences in macrofaunal abundance were found among sites and dates. At all sites, in the wet season, the number of taxa was low and dominance was high, especially in the Caeté Bay. The polychaete Nephtys fluviatilis only occurred in the Caeté Bay in the wet season, and yet was the dominant taxon (22.7% of total abundance). The Ajuruteua beach and Canela island samples were composed of typically marine taxa. The polychaete Armandia sp., the gastropod Olivella minuta, mysiid and phoxocephalid crustaceans and the echinoderm family Mellitidae were most abundant in the dry season at Canela island. Salinity was the most important environmental factor associated with high numbers of taxa in the dry season. Silt and turbidity were associated with low numbers of taxa in the wet season. In conclusion, the subtidal benthic macrofauna at Canela island, Ajuruteua beach and the Caeté Bay is mainly composed of polychaetes and crustaceans. The higher freshwater discharge in the wet season, resulting in lower salinity, higher percentage silt and greater turbidity, is associated with lower abundance, fewer taxa and a different faunal composition at Canela and Ajuruteua, and strong dominance of an oligohaline polychaete in the Caeté Bay

Integration of different sediment characteristics to discriminate between sources of coastal sediments

Abstract In order to investigate the effects of geological setting and the surrounding lithology on coastal sediment samples, four properties were analysed in a series of samples collected from different localities: colour determined by spectrophotometry; particle size distribution determined by laser granulometry; chemical composition determined by ICP-MS (inductively coupled plasma mass spectrometry); and low-field magnetic susceptibility determined using a susceptibility meter. A hierarchical cluster analysis was applied to ascertain the capacity of the different properties for discrimination between samples from the different geological settings. The study reveals that colour analysis only allowed discrimination between different geographical areas; particle size distribution allowed separation between dune and beach samples; chemical composition allowed discrimination between both different geological settings and also between dune and beach sands; and, finally, the combination of magnetic susceptibility with colour and particle size distribution allowed for clear discrimination between geological settings, and between beach and sand dunes. The studied samples are part of a larger and growing collection of data, and a more extensive evaluation will continue to be made for a more definitive assessment of the use of different characteristics for discrimination. So far, the results give confidence that it is meaningful to use these characteristics, especially when examined in combination, to distinguish between different locations.

Comparison of Multi-Drug Resistant Environmental Methicillin-Resistant Staphylococcus aureus Isolated from Recreational Beaches and High Touch Surfaces in Built Environments

Over the last decade community-acquired methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major cause of disease in the general population with no health care exposure or known classical risk factors for MRSA infections. The potential community reservoirs have not been well defined though certain strains such as ST398 and USA300 have been well studied in some settings. MRSA has been isolated from recreational beaches, high-touch surfaces in homes, universities, and other community environmental surfaces. However, in most cases the strains were not characterized to determine if they are related to community-acquired or hospital-acquired clinical strains. We compared 55 environmental MRSA from 805 samples including sand, fresh, and marine water samples from local marine and fresh water recreational beaches (n = 296), high touch surfaces on the University of Washington campus (n = 294), surfaces in UW undergraduate housing (n = 85), and the local community (n = 130). Eleven USA300, representing 20% of the isolates, were found on the UW campus surfaces, student housing surfaces, and on the community surfaces but not in the recreational beach samples from the Northwest USA. Similarly, the predominant animal ST133 was found in the recreational beach samples but not in the high touch surface samples. All USA300 isolates were multi-drug resistant carrying two to six different antibiotic resistance genes coding for kanamycin, macrolides and/or macrolides-lincosamides-streptogramin B, and tetracycline, with the majority (72%) carrying four to six different antibiotic resistance genes. A surprising 98% of the 55 MRSA isolates were resistant to other classes of antibiotics and most likely represent reservoirs for these genes in the environment.

Density of Enterococcus sp in recreational waters and beach sand in São Vicente-SP, Brazil and its relationship to abiotic parameters

cities attract a large number of tourists for their beautiful landscape and recreational activities, increasing the municipalities’income source. Thus, a need is clear for the establishment of beach quality monitoring programs to ensure bathers health. Althoughthere is an effective monitoring program for recreational waters in Brazil there are no programs to certify the quality of beach sands. Inthis sense, the aim of this work was to analyze the density of bacteria from the genus Enterococcus in both sand and water from twobeaches from Sao Vicente, Sao Paulo (Brazil) and correlate these densities to abiotic parameters such as: temperature, salinity, particlesize, organic matter and tides). Water and sand samples were collected during February 2006 on the beaches of Gonzaguinha eIlha Porchat and bacterial densities were determined by membrane filter technique. Temperature and salinity were measured in situwith a thermometer and a refractometer while particle size and organic matter were determined according to methods described bySuguio and Dean. There were significant differences between densities found in water and sand (p=0.004), being approximately 20times higher in Gonzaguinha’s beach sands. Similar results were found for Ilha Porchat beach samples, being the densities found insand 3 times greater than those found in water. Both beaches showed a negative correlation between bacterial densities and salinityand temperature, suggesting a deleterious effect of these parameters on the bacterial community. On the other hand, no correlationwas found between organic matter and particle size and bacterial densities. This work demonstrates that there is a great necessityfor monitoring beach sand since the evaluation of beach quality is an important part of integrated coastal management programs.

Structure of the littoral fish assemblage in an impounded tributary: the effects of macrophytes presence (subtropical region, Brazil)

To evaluate the effects of macrophytes presence in the structure of littoral fish assemblages in the littoral zone, monthly samples were collected from September, 2006 to August, 2007 in an impounded tributary of the Itá Reservoir, the Fragosos River, located in the Upper Uruguay River Basin. Fish were collected using a beach seine and sampling was conducted in the littoral zone inside a macrophyte stand and in an area with no macrophytes. A total of 5,191 fish were captured during the study period. Fish assemblage attributes (fish abundance, species richness, and diversity) varied significantly between sampling months and areas. The abundance of Astyanax cf. bimaculatus, Astyanax fasciatus, Geophagus brasiliensis, and Gymnotus carapo also varied significantly between sampling months and areas. Detrended Correspondence Analysis showed a clear spatial segregation at the first axis and a slight temporal segregation at the second axis. These results were confirmed by Multiple Response Permutation Procedure analysis. Apparently, the presence of the aquatic macrophytes is not the only factor influencing the distribution of littoral fish assemblages in the Fragosos River. Littoral fish seem to be taking advantage of low- to medium-sized macrophyte stands, but few species used maximum-sized stands.

Antibiotic Resistance and Virulence Among Enterococci Isolated from Teluk Kemang Beach, Malaysia

We report the first study on virulence among antibiotic resistant Enterococci in coastal bathing waters in Malaysia. A total of forty-two isolates recovered from Teluk Kemang beach samples were screened for antibiotic resistance and virulence activity. About 54 % of the Enterococci isolates were resistant to tested antibiotics. Resistance was highest to ampicillin (94.66 %) and least to novobiocin (1.39 %). There were no significant differences (p<0.05) in the observable proportion of resistant strains for all the antibiotics tested across the three species encountered. Generally antibiotic resistance index ranged from 0.51 to 0.58. While all recovered isolates failed to lyse haemoglobin in 5 % sheep blood-supplemented agar, gelatinase activity was notable among the E. faecium isolates (69.23 %). This value was significantly higher (p<0.05) than was observed for E. faecalis and E. spp. Protease activity appeared more profound among the three species as more than 80 % hydrolysed milk casein.

Shipboard magnetic field “noise” reveals shallow heavy mineral sediment concentrations in Chesapeake Bay

Shipboard magnetic field data collected over Chesapeake Bay exhibit low-amplitude, short-wavelength anomalies that most likely indicate shallow concentrations of heavy mineral sediments. Piston core layers and black sand beach samples exhibit enhanced magnetic susceptibilities and carry remanent magnetization, with mineralogical analyses indicating ilmenite and trace magnetite and/or maghemite and hematite. The anomalies are subtle and would be filtered as noise using traditional approaches, but can instead be highlighted using spectral methods, thus providing nearly continuous coverage along survey tracks. The distribution of the anomalies provides constraints on relevant sorting mechanisms. Comparisons to sonar data and previous grab samples show that two of three areas surveyed exhibit short-wavelength anomalies that are clustered over sand-covered areas, suggesting initial sorting through settling mechanisms. This is supported by a correlation between core magnetic susceptibility and grain size. Near the Choptank River, where sediment resuspension is wave-dominated, anomalies show a sharp decrease with seafloor depth that cannot be explained by signal attenuation alone. In Pocomoke Sound, where both tidal currents and wave-action impact sediment resuspension, anomalies show a more gradual decrease with depth. Near the mouth of the bay, where there is a higher influx of sediments from the continental shelf, short-wavelength anomalies are isolated and do not appear to represent heavy mineral sand concentrations. These combined observations suggest the importance of further sorting by erosional processes in certain parts of the bay. Additionally, comparisons of these data to cores sampling pre-Holocene sediments suggest that the sorting of heavy minerals in higher energy, shallow water environments provides a mechanism for correlations between core magnetic susceptibility and sea-level changes.

Reducing the effects of environmental inhibition in quantitative real-time PCR detection of adenovirus and norovirus in recreational seawaters

Quantitative real-time PCR (qPCR) is used commonly to detect adenovirus (Ads) and norovirus (Nvs) in recreational waters. However, qPCR detection may be limited by interference from inhibitory substances found in recreational waters. In previous work, viruses in Avalon and Doheny Beach water samples were concentrated by electropositive cartridge filtration and PEG precipitation, and high inhibition was found in the samples when using qPCR for detection of Ads and Nvs. Therefore, different approaches were evaluated for removal or blocking of inhibitory compounds that affect qPCR. Avalon and Doheny concentrates were spiked with known amounts of Ads 41 and Nvs GII, and spiked deionized water was used as a positive control. Modifications included gel chromatography with columns of Sephadex G-200/Chelex 100, different sample volumes for nucleic acid extraction, organic solvent extraction, and nucleic acid precipitation. The efficiency of each treatment varied according to sampling location and virus type. The best option for improved Nvs detection by reverse transcription-qPCR was to reduce the sample volume for nucleic acid purification. The best option for improving Ads detection in both beach samples was Sephadex/Chelex spin column chromatography. Chloroform extraction only improved virus detection in Doheny Beach samples but not in Avalon Beach samples. Observed differences in effective treatments between viruses may be related to the different PCR targets, amplification conditions, and enzymes used in each assay, and differences between beaches may be related to differences in PCR inhibitory environmental compounds at each location. The results suggest that methods for detecting viruses from marine beaches, including treatments for the removal of PCR inhibitory compounds, should be optimized for each sampling site and probably for each virus of interest.

Provenance, transport and composition of Dendê Coast beach sands in Bahia, central coast of Brazil

The great physiographic diversity of the Dendê Coast favors the production of different beach sediment types, including bioclastic components. In this study 74 beach samples collected at 2 km intervals were used to evaluate beach sediment composition. For each sample, 300 grains were identified for each grain size class coarser than 0.125 mm, using a binocular microscope. The beach sediments of the Dendê Coast are essentially siliciclastic (80-100%). Quartz is the major component (70-100%). Only at the Tinharé and Boipeba islands bioclasts are major components of beach sands reaching up to 80-100%. These sediments are made up essentially of fragments of Halimeda, reaching percentages up to 70%. Coralline algae and mollusks also contribute significantly to these sediments (up to 30%). The results obtained show that the spatial distribution of the bioclastic components provide important information on the environmental conditions present at the shoreline (energy levels, availability of hard substrates and protected areas, pattern of sediment dispersion) and on the sediment sources as well. The composition of the beach sediments on the Dendê Coast reflects the present day environmental conditions and show that these sediments do not experience significant lateral transport. This situation is favored by an impeded longshore transport that characterizes most of the region. Although, in general, the rivers that discharge on the Dendê Coast appear to transport few sediments to the coastal zone, the presence of heavy minerals, micas and feldspars suggests river contributions to the beach sediments. On the other hand, the coral and coralline algae reefs, besides offering a natural protection to the shoreline, also represent an important source of beach sands.

Assessment of regional and local biodiversity in tropical and subtropical coastal habitats in the East African Marine Ecoregion

The transboundary networks of Marine Protected Areas (MPAs) project, TRANSMAP, assessed local turnover and regional biodiversity across the East African Marine Ecoregion, where inter-governmental co-operation has been working to connect local MPAs. The benthic fauna in the three most dominant habitats on this coastline—beaches, mangroves and seagrasses—were studied in two Regions (Northern Region, 10–13°S; Southern Region, 25–28°S). Meiofaunal taxa were used as the model faunal group owing to their diversity and abundance across habitat types and environmental conditions. Meiofaunal abundance averaged 2,500 individuals 10 cm−2 and was generally higher in mangrove and seagrass sediments than on the beaches, and was significantly different between habitats × Regions. In total, 18 taxa were recorded with highest diversity in the beach samples. Diversity indices and assemblage structure were significantly different between habitats, but also Regions. Specific granulometric 1Φ size classes, shore-height and number of rain days were the factors most significantly correlating with the observed assemblage patterns. Additionally, the size of a MPA and latitude (which correlated with MPA age, but not number of rain days), were the factors fitting best with meiofaunal assemblage patterns across the beaches, the habitat for which the most comprehensive data were generated. Sample diversity was higher in the Southern Region, and although within- and across-habitats diversity were similar across the Regions, the two Regions appeared to provide complementary habitats and supported different assemblages. Within the Regions, beaches (the only habitat for which more than one location was sampled) were significantly different between Locations, supporting the establishment of multiple protected locations of the same habitat within each transboundary MPA.

Comparison of Enterococcus density estimates in marine beach and bay samples by real-time polymerase chain reaction, membrane filtration and defined substrate testing

Currently, densities of Enterococcus in marine bathing beach samples are performed using conventional methods which require 24h to obtain results. Real-time PCR methods are available which can measure results in as little as 3h. The purpose of this study was to evaluate a more rapid test method for the determination of bacterial contamination in marine bathing beaches to better protect human health. The geometric mean of Enterococcus densities using Enterolert® defined substrate testing and membrane filtration ranged from 5.2 to 150MPN or CFU/100mL and corresponding qPCR results ranged from 6.6 to 1785CCE/100mL. The regression analysis of these results showed a positive correlation between qPCR and conventional tests with an overall correlation (r) of 0.71. qPCR was found to provide accurate and sensitive estimate of Enterococcus densities and has the potential to be used as a rapid test method for the quantification of Enterococcus in marine waters.