Bay Samples Research Articles

Large-scale sexual segregation of bowhead whales

Skin biopsy samples from 806 bowhead whales Balaena mysticetus collected between 1995 and 2010 at 4 locations in Nunavut, Canada, and at 1 locality in West Greenland were used for determination of sex and sexual segregation of bowhead whales in the Baffin Bay stock. There was a significant dominance of females in the Disko Bay samples (78%), whereas the sex ratio in aggrega- tions in Nunavut was not significantly different from 50:50. Data on the body length of whales sug- gest that primarily large mature whales without calves occupy Disko Bay, whereas primarily mother- calf pairs are found in Foxe Basin. On a broader scale, Baffin Bay is more widely used by adult males and resting or pregnant females from Disko Bay, while Prince Regent, Gulf of Boothia, Foxe Basin, and northwestern Hudson Bay are also used by nursing females, calves, and sub-adults. The most parsimonious explanation for the large-scale spatial segregation of sexes in bowhead whales is that mature females without calves utilize Disko Bay as a foraging ground during certain parts of their reproductive cycle. Acoustic recordings of singing males indicate that Disko Bay may also be a mat- ing ground, where some males may be following estrous females into the bay.

Revisiting Coos Bay, Oregon: A re-examination of funginite–huminite relationships in Eocene subbituminous coals

Coal petrography has advanced significantly since Reinhardt Theissen and James Schopf pioneered the use of thin sections to examine coals from Coos Bay Oregon, and to many coal petrographers the nomenclature used in that study is irrelevant. The Schopf (1947) study was a ground-breaking examination of maceral relationships that need to be part of the working vocabulary of modern petrographers. To support this, a re-examination of the Coos Bay thin section collection was undertaken, using modern nomenclature for low-rank coals under reflected light. This particular collection was chosen in part because of the abundance of fungal material reported by Schopf. Fungal material in coal and its association with huminite/vitrinite macerals provides important information about the decompositional history of the coal and allows coal dominated by oxic processes to be differentiated from coal dominated by anoxic processes. In the Coos Bay samples, predominantly oxic intervals contain well-preserved fungi, including spores, sclerotia, and hyphae, while anoxic intervals contain no fungi. ►Revisitation of Schopf (1947) ground-breaking examination of maceral relationships. ►Use of modern reflected light nomenclature for thin sections. ►Huminite–funginite relationships explored. ►Oxic, attrinite-rich intervals are also rich in funginite. ►Further evidence for multiple pathways of inertinite formation

Variation in ultrafiltered and LMW organic matter fluorescence properties under simulated estuarine mixing transects: 2. Mixing with photoexposure

Ultrafiltered and low molecular weight dissolved organic matter (UDOM and LMW‐DOM, respectively) fluorescence was studied under simulated estuarine mixing along with moderate photoexposure using Delaware, Chesapeake, and San Francisco Bays (USA) natural organic matter. UDOM was produced by tangential flow ultrafiltration (TFF) from the marine (>33 PSU), mid‐estuarine (∼16 PSU), and freshwater (<1 PSU) members. TFF permeates (<1 kDa) were used to create artificial salinity transects nominally ranging from ∼0 to ∼36, with 4 PSU increments. UDOM or permeate (as control) from freshwater and mid‐estuary was added to each salinity mix in the artificial transect to determine the impact of mixing behavior on optical properties. Three‐dimensional fluorescence excitation‐emission matrix (EEMs) spectra were generated for each end‐member permeate (LMW fraction) and UDOM through the full artificial mixing transect. Fluorescent properties representing standard‐identified peaks, fluorescence ratios and excitation‐emission characteristics were assayed as previously reported. However, in this study, each sample was additionally photobleached for three days (nominally) to determine the coupled effect of estuarine mixing and photobleaching on LMW and UDOM fluorescence. Permeates, except Delaware Bay samples, were more bleached at lower salinities (<16). This effect was especially noticeable for mid‐estuarine LMW organic material which was highly bleached at low salinities. Humic‐type UDOM was generally bleached less at low salinities, maximally at mid‐salinities, and less as it mixed toward the ocean end‐member. As with mixing alone experiments, the B peak showed virtually no variability in the LMW and UDOMs fraction and was not significantly bleached. The N and T peak behaved similarly to one another and were significantly bleached. PCA and PARAFAC models confirmed trends for individual peaks. A four‐dimensional PARAFAC model with pre‐ and post‐bleached as the fourth dimension showed increases in the T peak fluorescence after photobleaching (with some overlap of the B and N peak). Results from this study indicate that coupled mixing and photobleaching can alter CDOM fluorescence in ways which might increase the difficulty in using CDOM as a proxy for DOM in regional carbon cycling biogeochemical models.

THE STUDY ON MORPHOLOGICAL TAXONOMY OF <I>PSEDUO-NITZSCHIA PSEUDODELICATISSIMA</I> COMPLEX

Increasing evidence show that cryptic and pseudo-cryptic species are widespread in several diatom taxa. This is the case with the genus Pseudo-nitzschia, which includes chain-forming pennate diatoms that bloom both in coastal and open ocean waters. In the last years, up 10 new species have been described on the basis of morphological and mo-lecular investigations, and some of them are only distinguishable on the basis of minute ultrastructural features of their siliceous frustulae. This is the case of P. pseudodelicatissima complex. It has been confirmed that P. pseudodelicatissima complex was a kind of pelagic diatom species which distribute commonly in Chinese coastal waters. Because of few subtle morphological features which just could be observed under electronic microscope (EM) among P. pseudodelica-tissima complex taxa, it is greatly difficult to reach accurate identification and there are many debates at present. For clarifying the species diversity of P. pseudodelicatissima complex and its dominant species in Daya Bay, water and net samples were collected from six stations in summer (August), 2007. All samples were fixed with Lugo’s solution in situ and brought back to the laboratory. Then, they were concentrated to a final volume about 2—10 mL by settlement over-night for several times. These samples could be observed and analyzed under light microscope. For observation under transmission electron microscope, subsamples were taken and treated through several steps. Firstly, after dropped into same volume of concentrated H2SO4, these samples were boiled in the water bath for about 15—20 minutes to remove the organic materials. Secondly, these samples should be washed to neutrality with distilled water for several times. Then, these samples could be observed, identified, photographed and counted under transmission electron microscope. Including six species, P. caciantha Lundholm, Moestrup Hasle, P. calliantha Lundholm, Moestrup Hasle, P. cus-pidata (Hasle) Lundholm, Moestrup Hasle, P. mannii Amato Montresor, P. pseudodelicatissima (Hasle) Lundholm, Hasle Moestrup and P. sinica Qi Wang, P. pseudodelicatissima complex were found. And P. caciantha, P. callian-tha, P. mannii were identified as three newly recorded diatom species for China. Along with LM and TEM photos, the detailed morphological description, habits and ecological distribution of these six species were given in this paper. Si-multaneously, the taxonomic comparison among resembling species were made. The six species described in this paper have morphological features in common: the long and slender valves, the present of a larger central interspace, the uniseriate striae, the similarity of the structure of the valve face and the valve mantle, and the hexagonal perforation pattern of the poroid hymen. However, several other features such as structure of the poroid hymen, density of fibulae and striae, the width and shape of valves, and the structure of the cingular bands differed among the species and could be used for differentiating these six species from each other. After investigation of the cell abundance of each species, it is concluded that the most common species distributing in Daya Bay is P. calliantha, not P. pseudodelicatissima which has been reported formerly.

Microcystin concentrations in Nile tilapia (Oreochromis niloticus) caught from Murchison Bay, Lake Victoria and Lake Mburo: Uganda

Catches of the economically important Nile tilapia (Oreochromis niloticus L.) from two eutrophic tropical lakes in Uganda, Lake Mburo and Murchison Bay, Lake Victoria, were examined to determine the presence of microcystins (MCs) in gut, liver and muscle of the fish. Analysis for MCs (RR, LR and YR) in both fish and water samples was by liquid chromatography coupled with mass spectroscopy (LC-MS) method. Physico-chemical parameters were also measured to establish the status of both lakes. MC-RR was the most prominent MC detected in Lake Mburo and Murchison Bay samples, there was no evidence of significant seasonal variation in the concentration of MCs in fish tissue. MCs were detected in all water samples from both study lakes. The mean concentration of MCs in water was found higher in dry times for Lake Mburo (P < 0.05) and higher in wet times for Murchison Bay (P < 0.05). MC concentrations in the fish guts were positively related with MC concentrations in water samples from Murchison bay (P < 0.05), no such correlation was found in Lake Mburo. In eutrophic tropical lakes, fish seem to have a high tolerance to the toxicity of cyanotoxins including MCs. However, there is a possibility of accumulating these toxins in their tissue with the threat of transferring them higher up in the food chain. Due to a low sample size and short sampling period, the results can only serve to highlight the potential risk of MC accumulation in Nile tilapia in these lakes. Further studies are needed for the purpose of risk assessment.

Population identification of common cuttlefish (&lt;em&gt;Sepia officinalis&lt;/em&gt;) inferred from genetic, morphometric and cuttlebone chemistry data in the NE Mediterranean Sea

The population structures of the common cuttlefish Sepia officinalis from the north-eastern Mediterranean (Antalya and Iskenderun Bays), Aegean (Izmir Bay) and Marmara Seas were analyzed with mtDNA PCR-RFLP, body morphometry and cuttlebone chemistry. Analysis of a ND 5/6 (Nikotin Amid Adenin Dehidrojenaz-5/6) gene segment of mtDNA revealed seven haplotypes from 120 individuals. No haplotype sharing was observed among sampling sites. The average nucleotide divergence between samples was 0.009390, and the highest genetic divergence (0.015279) was observed between the Iskenderun Bay and Marmara Sea samples. The lowest genetic divergence (0.003786) was between the Aegean Sea and Antalya Bay samples. Highly significant differences (P S. officinalis in Turkish coastal waters.

Spatial variations in depth-distribution of trace metals in coastal wetland sediments from Quanzhou Bay, Fujian Province, China

Four short cores were obtained from the coastal wetland of the Quanzhou Bay, Fujian Province, China, and sediment samples were analyzed with a Mastersizer 2000 for grain size analysis and an Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) for trace metal analysis. The results of grain size analysis show that the wetland sediments are mainly composed of silt and clay, and the distribution of median grain size is affected by human activities obviously. The results of trace metal analysis show that the wetland sediments mainly originate from terrestrial materials in the Luoyangjiang River estuary and from contaminants discharged from adjacent rivers in Shuitou area. The heavy metal contamination in Luoyangjiang estuary decreased from 1984 to 2004 due to industry transformation, but has increased since 2004 because of the discharge of contaminants to the Jinjiang River and much living sewerage to the bay, and a large number of trace metals are trapped within Spartina alterniflora marsh.

Mine water-induced gradients in sediment metals and arcellacean assemblages in a boreal freshwater bay (Petkellahti, Finland)

Sediment chemistry and arcellacean community composition were analyzed to study the ecological effects of copper mine-derived acidic and metal-rich waters in a freshwater bay in eastern Finland. To track spatial and temporal changes in the bay, 32 mine-impacted (top) and pre-impact (bottom) samples were analyzed from 16 short sediment cores taken along a transect extending from the pollution source. In addition, short cores from the impacted and reference sites were studied. Recent sediments displayed a geochemical gradient from the inner bay, where mine water is discharged, to the outer bay. Inner bay sites were enriched with C, S, and Fe, whereas Mn was depleted, but has precipitated in the outer bay. Among the heavy metals, Cu, Al, Zn, and Ni concentrations had increased in the inner and mid bay, while Co and Cd concentrations had increased at mid-bay sites. The change from the natural to mine-impacted condition was also seen in faunal gradients. According to ordination and distance measures, the greatest changes in species composition occurred in the inner bay, with fairly small changes in the outer bay. Numerical methods suggested that metals (Cu, Pb, Al, Zn, Cr), redox-sensitive elements (Fe, Mn), organic carbon and nutrients could be related to changes in arcellacean assemblages. Geochemical changes in the impacted core started at ~20 cm with increases in S alternating with peaks in Cr and Mg. Heavy metal concentrations increased markedly at 10 cm, after the active mining period, suggesting the beginning of acid mine drainage. Geochemical changes at ~20 cm were already apparent in the arcellacean assemblages, but the most notable change coincided with the geochemical shift at 10 cm, with signs of decreased pH. Numerical methods suggest that mining-related metals Co, Cu, Zn and Ni co-vary with arcellaceans, but Al appears to behave independently with respect to the species data.

Molecular Investigation of Streptococcus agalactiae Isolates from Environmental Samples and Fish Specimens During a Massive Fish Kill in Kuwait Bay

This study was undertaken to identify and characterize bacterial isolates obtained simultaneously from dead fish samples during a massive fish kill in Kuwait Bay and sewage-water samples running into Kuwait Bay using conventional and molecular techniques. Of the 71 bacterial isolates studied; 66 were recovered from 7 different fish species and 5 strains were isolated from sewage samples. The species-specific identity of the isolates was established by phenotypic characteristics and by PCR amplification of 16S rRNA by using Streptococcus agalactiae-specific primers. The genotyping of 12 isolates from fish samples and all 5 isolates from sewage samples was performed by random amplification of polymorphic DNA (RAPD) analysis. Culture methods identified 44 of 66 (67%) and 4 of 5 (80%) isolates obtained from fish and sewage samples, respectively, as S. agalactiae. The PCR amplification of 16S rRNA not only confirmed the results of conventional methods but also resulted in additional identification of 14 of 66 (21%) isolates obtained from fish samples and the remaining isolate recovered from sewage sample, as S. agalactiae. A total of 9 RAPD patterns were observed among the 17 isolates studied; these RAPD patterns were grouped into three clusters. Interestingly, four of the isolates recovered from sewage samples produced nearly identical RAPD band patterns (85-100% similarity) with some of the S. agalactiae strains isolated from Mullet kidney and brain indicting the possibility of sewage being the source of infection.

Sediment denitrifier community composition and nirS gene expression investigated with functional gene microarrays

A functional gene microarray was used to investigate denitrifier community composition and nitrite reductase (nirS) gene expression in sediments along the estuarine gradient in Chesapeake Bay, USA. The nirS oligonucleotide probe set was designed to represent a sequence database containing 539 Chesapeake Bay clones, as well as sequences from many other environments. Greatest nirS diversity was detected at the freshwater station at the head of the bay and least diversity at the higher salinity station near the mouth of the Bay. The most common OTUs from the sequence database were detected on the array with high signal strength in most samples. One of the most abundant OTUs, CB2-S-138, was identified as dominant at the mid-bay site by both microarray and quantitative PCR assays, but it comprised a much smaller fraction of the assemblage in the north and south bay samples. cDNA (transcribed from total RNA extracts) targets were hybridized to the same array to compare the profiles of community composition at the DNA (relative abundance) and mRNA (gene expression) levels. Only the three dominant denitrifying groups (in terms of relative strength of DNA hybridization signal) were detected at the mRNA level. These results suggest that the most actively denitrifying groups are responsible for most nirS expression as well.

Genetic and morphological evidence for localised interspecific gene flow in Phormium (Hemerocallidaceae)

Gene flow between two species of Phormium, P. tenax and P. cookianum, was investigated by analysis of morphology, AFLP profiles, and chloroplast simple sequence repeats (cpSSRs). We examined 44 wild samples of Phormium, focusing on Okiwi Bay (Marlborough, New Zealand), where the two species grow in close proximity. Two genetic groups corresponding with P. tenax and P. cookianum are evident in analyses of AFLP profiles from Okiwi Bay. The profiles of Okiwi Bay plants were also compared with profiles from three hypothetically pure P. cookianum populations from Marlborough, and a representative sample of P. tenax combined from sites throughout New Zealand. Bayesian analysis of genetic admixture suggests that all of the plants resembling P. tenax and most of the plants resembling P. cookianum sampled from Okiwi Bay are admixed (i.e., of hybrid origin). Neighbour Net and principal component analyses reveal that P. cookianum and P. tenax from Okiwi Bay are genetically intermediate between “pure” populations of the species. Further, all of the Okiwi Bay samples share the same chloroplast haplotype. Analysis of morphological characters comparing a small number of Okiwi Bay P. tenax plants to selected P tenax plants from throughout New Zealand under common garden conditions confirm that the Okiwi Bay population includes plants with unusually small stature and fruit characters approaching P cookianum. These results support a hypothesis of local introgression between P. tenax and P. cookianum.

Phylogenetic analysis of the composition of bacterial communities in human-exploited coastal environments from Mallorca Island (Spain)

The phylogenetic analysis of bacterial communities in environments receiving anthropogenic impact could help us to understand its effects and might be useful in the development of monitoring or management strategies. A study of the composition of 16S rDNA clone libraries prepared from bacterial communities in water samples from a marina and a beach on the coast of Mallorca (W. Mediterranean) was undertaken at two time points, corresponding to periods of maximum and minimum anthropogenic use of this area for nautical and recreational activities. Libraries generated from the marina were significantly different from those from the beach and a non-impacted, bay sample. In the marina, a predominance of sequence types was observed related to bacterioplankton from nutrient-enriched environments or typically associated with phytoplankton, such as certain phylotypes of the Roseobacter clade, OM60 clade and Bacteroidetes. Similar results were found in the summer beach library but not in the winter one, in which there was an increase in the number of clones from oligotrophic groups, in agreement with lower chlorophyll content and bacterial counts. Therefore, nutrient enrichment seemed to be an important driver of the composition of bacterial communities in sites receiving direct human impact. Interesting sequence types from the Cryomorphaceae and group agg58 ( Bacteroidetes) were exclusively found in beach libraries, and the reasons for this distribution deserve further study. Clones related to putative hydrocarbon-degrading bacteria of the genus Acinetobacter were observed in the marina, in agreement with a certain degree of pollution at this site. Non-marine sequences belonging to the Actinobacteria predominated over marine groups in the summer library from the marina and, therefore, unusual communities might be transiently present in this enclosed environment. Overall, the composition of the bacterial communities in these environments agreed well with the defining characteristics of the environments sampled.

New evidence from the western Canadian Arctic Archipelago for the resubmergence of Bering Strait

Widespread molluscan samples were collected from raised marine sediments to date the last retreat of the NW Laurentide Ice Sheet from the western Canadian Arctic Archipelago. At the head of Mercy Bay, northern Banks Island, deglacial mud at the modern coast contains Hiatella arctica and Portlandia arctica bivalves, as well as Cyrtodaria kurriana, previously unreported for this area. Multiple H. arctica and C. kurriana valves from this site yield a mean age of 11.5 14C ka BP (with 740 yr marine reservoir correction). The occurrence of C. kurriana, a low Arctic taxon, raises questions concerning its origin, because evidence is currently lacking for a molluscan refugium in the Arctic Ocean during the last glacial maximum. Elsewhere, the oldest late glacial age available on C. kurriana comes from the Laptev Sea where it is < 10.3 14C ka BP and attributed to a North Atlantic source. This is 2000 cal yr younger than the Mercy Bay samples reported here, making the Laptev Sea, ~ 3000 km to the west, an unlikely source. An alternate route from the North Atlantic into the Canadian Arctic Archipelago was precluded by coalescent Laurentide, Innuitian and Greenland ice east of Banks Island until ~ 10 14C ka BP. We conclude that the presence of C. kurriana on northern Banks Island records migration from the North Pacific. This requires the resubmergence of Bering Strait by 11.5 14C ka BP, extending previous age determinations on the reconnection of the Pacific and Arctic oceans by up to 1000 yr. This renewed ingress of Pacific water likely played an important role in re-establishing Arctic Ocean surface currents, including the evacuation of thick multi-year sea ice into the North Atlantic prior to the Younger Dryas geochron.

Geographic distribution of Karlodinium veneficum in the US east coast as detected by ITS-ferredoxin real-time PCR assay

Karlodinium veneficum is an ichthyotoxic dinoflagellate suspected to be responsible for massive fish kills. Because it is morphologically similar to Pfiesteria and related dinoflagellates, accurate abundance data of K. veneficum in the natural environment are difficult to obtain using light microscopy. In this study, species-specific real-time PCR assays were developed using the ferredoxin gene (KvFERR) and rDNA locus (partial internal transcribed spacer regions and 5.8S rDNA, KvITS). These assays were used to investigate the geographic and temporal distribution of K. veneficum from various estuaries and coastal regions of the Pacific and West Atlantic Oceans. In general, both genes gave similar quantitative results, detecting down to 0.1–1 K. veneficum cells mL−1. The higher occurrence frequency and abundance of K. veneficum were observed in Neuse River, North Carolina, Narragansett Bay, Rhode Island and Chesapeake Bay, MD, USA. Most of the KvITS sequences from North Carolina to Maine were identical to that of K. veneficum strain CCMP1975 (initially isolated from Chesapeake Bay), with 1–2 nucleotide substitutions occurring in sequences from Texas and Narragansett Bay samples. This result suggests the same origin and recent separation of K. veneficum populations living in this wide geographic range. In this study, K. veneficum was more abundant at 5–15°C and 4–20 psu.

Species distribution and antimicrobial resistance of enterococci isolated from surface and ocean water

The species identification and antimicrobial resistance profiles were determined for enterococci isolated from Southern California surface and ocean waters. Species identification was determined for 1413 presumptive Enterococcus isolates from urban runoff, bay, ocean and sewage water samples. The most frequently isolated species were Enterococcus faecalis, Enterococcus faecium, Enterococcus hirae, Enterococcus casseliflavus and Enterococcus mundtii. All five of these species were isolated from ocean and bay water with a frequency ranging from 7% to 36%. Enterococcus casseliflavus was the most frequently isolated species in urban runoff making up 36-65% of isolates while E. faecium was the most frequently isolated species in sewage making up 53-78% of isolates. The similar distribution of species in urban runoff and receiving water suggests that urban runoff may be the source of Enterococcus. No vancomycin or high level gentamycin resistance was detected in E. faecalis and E. faecium isolates. Enterococcus faecalis, E. faecium, E. casseliflavus and E. mundtii are the most commonly isolated Enterococcus species from urban runoff and receiving waters in Southern California. Determination of the Enterococcus species isolated from receiving waters and potential pollution sources may assist in determining the sources of pollution.

Analysis of airborne and waterborne particles around a taconite ore processing facility

Since the mid-1970s, samples of airborne and waterborne fibrous particulates have been collected in the area of the Northshore Taconite Ore Processing Facility by the Minnesota Department of Health (MDH), the Minnesota Pollution Control Agency (PCA), and the University of Minnesota. Indirect sample preparation has consistently been used although other aspects of the sampling methods and sites have varied and analytical procedures were altered over time as more accurate and precise microscopy methods were developed (i.e., phase contrast optical microscopy, transmission electron microscopy, transmission electron microscopy with energy dispersive spectroscopy). In the mid-1970s, levels of airborne fibrous particulate in the Silver Bay area averaged from 0.00030 to 0.03 f/ml. This level was significantly greater than levels of similar particulates in the St. Paul, MN area, although two of the Silver Bay sampling sites, considered individually, did not indicate levels of fibrous particulate markedly different than that seen in St. Paul. More recent sampling data (i.e., 1990–2001) indicate mean concentration of airborne fibrous particulates (amphibole-like fibrous particulates) of 0.0020 f/ml with a range of values from 0.0001 to 0.0140 f/ml. Such levels are not significantly different from those seen in other non-urban environments in the US and Europe. Concentrations of fibrous particulates in water samples were higher in the mid-1970 when iron ore tailings were being deposited in Lake Superior, but since the tailings have been deposited on land waterborne levels of fibrous particulate in the Beaver River have remained relatively constant averaging in the range of 7.5 MFL. This level is only slightly in excess of the current EPA drinking water standard for fibrous particulates. Review and consideration of this data is important in determining the potential health risks associated with airborne and waterborne fibrous particulates in the areas of the Northshore Taconite Ore Processing Facility.

Spatial modelling of the probability of obtaining a detectable concentration of ammonia in Moreton Bay, Australia

Ammonia is an important water quality variable, which in excess, can be detrimental to waterways and their ecosystems. In the Ecosystem Health Monitoring Program in South-east Queensland ammonia is monitored monthly, however, often more than 50% of the ammonia observations in Moreton Bay are below detection limit, making it difficult to draw useful inferences. In this paper a clipped Gaussian random field is used to spatially model and map the probability of detectable concentration of ammonia. The methodology is applied to the Moreton Bay samples collected in February 2005. The results suggest that for this month the oceanic impacted areas have higher probability of detectable ammonia concentration than the areas closer to the main sources of anthropogenic inputs.

Bacterial diversity, composition and dynamics in and around recreational coastal areas

A comparative study on the composition of bacterial communities in a coastal area in the West Mediterranean receiving the impact of recreation-derived activities (from a marina and a beach) was performed by terminal-restriction fragment length polymorphism (T-RFLP) of 16S rDNA along spatial and temporal scales. Interpolation of concentration of hydrophobic compounds, chlorophyll and bacterial cells in seawater over the geography of the sampling area using geographic information systems techniques (GIS) allowed the delineation of two different habitats: bay and marina (with low and high levels of impact respectively), and a transition zone between them. Accordingly, the 16S rDNA T-RFLP profiles of bacterial communities in the area differed mainly spatially, with gradual changes in community composition and structure when approaching the beach and marina. Bacterial communities in impacted areas had higher diversity and equitability, as well as different composition. The main bacterial populations inferred in bay samples, which were members of the Alphaproteobacteria (mainly SAR11 and Roseobacter groups), were replaced by a different population of the Roseobacter clade, and members of the Gammaproteobacteria and Bacteroidetes in more impacted areas. There were also differences in the dynamics of bacterial communities. While temporal variations in bacterial communities in bay samples were lower and mainly determined by temperature, an important factor for the functioning of this ecosystem, variation in impacted areas was more irregular, not so much temperature-driven, and in the case of the transition zone (beach) reflected the use of the coast during warmer periods.

Metal profiles used as environmental markers of Green Turtle (Chelonia mydas) foraging resources

The Baja California Peninsula, Mexico serves an important role for feeding and developing sea turtles. High concentrations of metals detected in green turtles (Chelonia mydas) from Magdalena Bay prompted an investigation into the sources of metals in the region. We compared metal concentrations in sea turtle tissues with plant species found in their stomach contents, and with the same species of plants collected inside a sea turtle refuge area known as Estero Banderitas. Differences in the metal concentrations between marine plant species were minimal. Principal components analysis of the percent contribution of individual metals to the overall metal signature of each plant or tissue sample generated three principal components that explained 80.7% of the total variance in the data. The plant samples collected within Estero Banderitas formed a separate grouping from the green turtle tissue samples and the plants from the stomach contents. The plants in the stomach contents contained greater percent contributions of Cd and Zn than the plants collected inside the bay, while Pb and Mn contributed more to the metal profiles in the bay samples. The metal profiles in the sea turtle tissues more closely resembled the stomach contents than the same species of plants collected within Estero Banderitas, and suggest that sea turtles collected inside Magdalena Bay use foraging resources outside of the Estero Banderitas region. This work supports the suggestion that metal profiles can be used as "environmentally acquired markers" to improve our understanding of the extent of sea turtle foraging areas.

Fonte e grau da contaminação por hidrocarbonetos policíclicos aromáticos (HPAs) de baixa massa molecular em sedimentos da baía de Todos os Santos, Bahia

A baía de Todos os Santos (BTS), localizada no Recôncavo Baiano, é a maior baía navegável do Brasil. Com aproximadamente 450 km de extensão, sua orla é recoberta por extenso manguezal e sedimentos recentes. Esse estudo foi desenvolvido para avaliar a possibilidade do impacto ambiental crônico induzido pelos 50 anos de exposição do local à indústria do petróleo. Hidrocarbonetos policíclicos aromáticos (HPAs) provenientes de fonte pirolítica foram identificados e quantificados em uma concentração total variando entre 1 - 408.629 ng.g-1. As mais altas concentrações de HPAs foram encontradas nos portos e nas áreas de transporte. Os índices moleculares Phe/An e An/(An+Phe) foram usados para identificar a fonte de contaminação por HPAs nas estações de amostragem estudadas. Todavia as concentrações de HPAs pirolíticos foram comparáveis com aquelas de zonas contaminadas (áreas da refinaria e de extração). No geral, os sítios de amostragem na baía de Todos os Santos foram contaminados, devido ao transporte de petróleo em escala individual ao longo da baía e, também, pelo resíduo de óleos a partir de embarcações motorizadas.