Studies on the tropical marine fungi of Brunei

Driftwood, mangrove roots and branches, and seaweeds were examined for marine fungi from beaches, rocky shorelines, an artificial lake and mangrove stands. Ninety-five species, some new to science were recorded. This is the largest number of marine fungi reported from a single study. Our knowledge of the geographic distributions of these fungi has been extended. New and rare species are illustrated at the light microscope and SEM levels.     

三峡工程和退田还湖对洞庭湖区东方田鼠种群的潜在影响

洞庭湖东方田鼠种群的暴发成灾与洲滩演替关系密切.湖泊泥沙淤积导致湖滩面积增加,大面积的湖滩为东方田鼠种群增长提供了重要基础;而围湖造田、为根除血吸虫病而围湖灭螺以及滥捕天敌是湖区东方田鼠20世纪70年代开始形成严重危害的直接原因.近些年实施的三峡工程和退田还湖会对洞庭湖环境产生深远的影响.三峡水库蓄水后对长江中下游水量的调节将导致洞庭湖中低位洲滩出露面积的增大,退田还湖的实施亦将直接增加湖滩面积,这都将会扩大东方田鼠潜在的栖息地,会使东方田鼠种群进一步增长.因此必须高度关注东方田鼠未来种群的数量变化趋势.     

An isolated population of fourhorn sculpins (Myoxocephalus quadricornis,family Cottidae) in a hypersaline high arctic Canadian lake

Freshwater sculpins probably evolved from marine ancestors which entered bodies of water such as proglacial lakes or lakes which were gradually isolated from the sea by isostatic rebound. Sculpins in fresh water lakes (Myoxocephalus thompsoni [Girard]) lack cephalic horns and live well below a depth of 10 m. Those in the sea (Myoxocephalus quadricornis [Linnaeus]) typically live above 10 m and possess a well developed set of four cephalic horns. The sculpins in Garrow Lake, North West Territories, are intermediate between the marine and fresh water forms with respect to their depth distributions and their cephalic horns (spines). As a consequence, Garrow Lake, which separated from the sea some 3000 years ago, serves as an excellent laboratory for studying evolutionary changes in this sculpin. The age of the lake was based on carbon-14 dates of the fossil pelecypods from raised beaches around the lake and from observations of rates of isostatic rebound in the area as reported by Dickman & Ouellet 1983 and Pagé et al. 1984. During the last 3000 years, the surface waters of Garrow Lake have freshened and its sculpins have apparently adapted to this top down freshening by occupying a depth where the salinity of the lake approaches that of sea water. As a result, the sculpin population in Garrow Lake lives deeper than the sculpin population in the nearby Garrow Bay. Thus, the deeper dwelling Garrow Lake sculpins appear to be less vulnerable to avian predation than their shallow water dwelling marine ancestors. It is hypothesized that reduced avian predation of the Garrow Lake sculpin population is associated with the observed reduction in their cephalic horns which impart a certain degree of disruptive colouration and disruptive pattern outline allowing the shallow dwelling marine species to blend in with its background in a manner which appears to make it less visible to avian predators.It is unfortunate that the three thousand year old Garrow Lake sculpin population is now endangered by mine tailings entering the lake from the nearby Cominco Ltd. mine. The entire food chain of the lake appears to have been severely impacted by lead and zinc mine tailings entering Garrow Lake at a rate of 100 metric tonnes per hour.     

Effects of sandy beach cusps on wrack accumulation,sediment characteristics and macrofaunal assemblages

Beach‐cast marine macroalgae and seagrasses, collectively termed wrack, provide shelter and habitat for beach fauna and can often provide a large input of energy and nutrients to sandy beaches. Wrack deposition on sandy beaches varies spatially and could be affected by morphological features on the beach face such as cusps. This study tested a series of hypotheses regarding the differences in wrack deposits, sediments and macrofaunal assemblages between cusp bays and horns on two beaches in South Australia. Bays had greater cover and larger pieces of wrack than horns. Sediment organic matter content was greater on horns than in bays but mean particle size did not differ consistently between bays and horns. Macrofaunal diversity was higher in bays and this pattern was probably driven by differences in the cover of wrack between bays and horns. Cusp morphology thus influences the distribution of wrack on the beach face, which in turn influences the distribution of macrofauna. Studies of sandy beaches with cusps should therefore be explicitly designed to sample cusp features and associated wrack deposits.     

Population genetic structure of the striped silverside, Atherinomorus endrachtensis (Atherinidae, Atheriniformes, Teleostei), inhabiting marine lakes and adjacent lagoons in Palau: marine lakes are "Islands" for marine species

Although evidence for the evolution of terrestrial species on islands continues to rapidly accumulate, little is known about the evolution of marine species in geographically isolated environments such as islands as ocean currents often facilitate gene flow among populations. In this study, we focused on marine lakes of the Palau Islands, which are considered to be true analogues of terrestrial islands for marine species. To examine evolutionary processes in marine lakes, we conducted population genetic analyses on marine lake and lagoon populations of the striped silverside, Atherinomorus endrachtensis, using two mitochondrial DNA markers differing in evolutionary rate, the cytochrome b gene and the control region. The analyses revealed that the amount of genetic diversity of marine lake populations is much lower than that of lagoon populations and high levels of genetic differentiation occur among marine lake and lagoon populations. The present study has shown that marine lake populations have been completely isolated and have differentiated from lagoon populations, and each marine lake population is experiencing different evolutionary processes. These findings clearly demonstrate that marine lakes are excellent environments for the evolutionary study of marine species.     

Community structure and diversity of marine ascomycetes from coastal beaches of the southern Gulf of Mexico

Diversity of marine fungi in the Gulf of Mexico remains unknown for the most part, therefore the geographical distribution patterns of these microorganisms are mostly unknown too. Twelve sandy beaches located in this sea were sampled to evaluate the diversity of marine fungi, revealed by fruiting on natural substrata incubated in the laboratory for up to 12 months. Species richness and diversity differed between beaches, and corresponded with the presence of main and highly polluted river mouths, nearshore marine environments, and core industrial and port developments. Contaminants and local anthropogenic activities may be reducing the diversity of marine ascomycetes. Connections between beaches and different nearshore habitats explain the high diversity observed, since they represent a varied source of substrata for decomposition and heterogeneous environmental conditions. We recognized four main local species distribution patterns. Moreover, the constrained correspondence analysis showed that temperature is a major environmental variable affecting the distribution of these fungi. By a linear regression we showed a significant relationship between temperature and diversity.     

Marine fungi from two sandy beaches in Portugal

The occurrence of marine fungi associated with, pieces of wood, driftwood and dead plant stems, in the intertidal zone of two sandy beaches on the Portuguese west coast, was surveyed for 5 mo. Out of 90 samples scanned 70% had sporulating marine fungi. Thirty-five marine fungal taxa were identified (27 Ascomycota, six anamorphic fungi and two unidentified taxa), out of which 11 species were common to both beaches. Most taxa were infrequent (< or =10%), with the exception of Kirschsteiniothelia maritima (10-20%). The average number of fungi per sample was 0.91 for both beaches. Fifteen species are new records for Portugal. Samples were examined immediately after they were taken to the laboratory, as well as after incubation in moist chamber, for up to 10 mo.     

Natural beaches confer fitness benefits to nesting marine turtles

Coastal ecosystems provide vital linkages between aquatic and terrestrial habitats and thus support extremely high levels of biodiversity. However, coastlines also contain the highest densities of human development anywhere on the planet and are favoured destinations for tourists, creating a situation where the potential for negative effects on coastal species is extremely high. I gathered data on marine turtle reproductive output from the literature to determine whether coastal development negatively influences offspring production. Female loggerhead (Caretta caretta) and green turtles (Chelonia mydas) nesting on natural beaches (as opposed to beaches with permanent development) produce significantly more hatchling turtles per nest; all else being equal, females that successfully produce more offspring will have higher fitness than conspecifics producing fewer offspring. Thus, female marine turtles nesting on natural beaches probably have higher fitness than turtles nesting on developed beaches. Consequently, populations nesting on natural beaches may be able to recover more quickly from the historic population declines that have plagued marine turtles, and some species may recover more quickly than others.     

Marine Lake Mogilnoe (Kildin Island,the Barents Sea): one hundred years of solitude

Lake Mogilnoe (Kildin Island, the Barents Sea) is a marine stratified lake, a refuge for landlocked populations of marine organisms. Unlike other known marine lakes from polar areas, which communicate with the sea by water percolation at the surface, Mogilnoe has a subterranean connection with the sea like tropical and subtropical anchialine lakes. Similarly to some other marine lakes, Mogilnoe has traditionally been considered to be biologically isolated from the sea and subject to little change. We review the current status of the physical features, zooplankton and benthos of Mogilnoe and trace changes that have occurred in the lake since the start of observations in 1894. The anaerobic bottom water layer has expanded by 100 %, while the upper freshwater layer has diminished by 40 %. The species diversity of zooplankton and macrobenthos has halved. The occurrence of Atlantic cod likens Mogilnoe to some other Arctic marine lakes while the presence of large flocks of sea anemones, scyphomedusae and suberitid sponges makes it similar to tropical anchialine lakes. Lake Mogilnoe is not entirely biologically isolated; accidental introduction of species from the sea does occur. We argue that the idealised model of an isolated steady-state ecosystem can be applied to a marine lake with caution. A model of fluctuating abiotic environment and partial biological isolation portrays the real situation better.     

An annual cycle,at constant temperature,in a model sandy beach. II. Microbial biology

A model sandy beach successfully mimicking the natural environment has been operated under controlled conditions at a constant temperature (5°C, representative of British winter coastal sea-water temperatures) for a year. During this time the bacterial population of the sand and inundating sea water has been enumerated. Bacterial numbers were highest near the high and low water marks and had a minimum in between on the beach slope; they decreased with depth in the sand profile and showed little variation with time. A number of the bacteria were isolated from the sand system and a preliminary classification attempted. The results are discussed in relation to the meagre literature pertaining to the microbial biology of natural marine sandy beaches.     

Contaminated marine wounds--the risk of acquiring acute bacterial infection from marine recreational beaches.

An animal model was used to determine the potential for causing wound infections of bacteria isolated from marine recreational beaches in Hong Kong. Water samples were characterized physically, chemically and bacteriologically and used to inoculate artificially-induced wounds in rats. Morbidity and mortality correlated significantly (P < 0.01) with MacConkey plate counts and faecal coliform counts (membrane filtration) and inversely with salinity of the water. The majority of deaths were due to infection caused by marine and estuarine bacteria rather then enteric organisms. A total of 318 bacterial strains was isolated from the wounds and blood of animals inoculated with seawater, of which 242 were marine/estuarine (predominantly Vibrio spp., Aeromonas hydrophila and Pseudomonas putrefaciens) and 40 were enterobacteria. The virulence of the animal strains were comparable with those from clinical sources.     

In depth review of the ecology of arenicolous marine fungi

As an ecotone, sandy beaches exist within a multi-dimensional mesh of environmental gradients, shaped by numerous parameters (e.g. temperature, humidity, wave action, sand particle size and salinity). These limit the proliferation of a narrow group of fungal species. Obligate arenicolous marine fungi are an ecological assemblage of sand-associated heterotrophs that inhabit sandy beaches. These organisms have evolved to cope with dynamic beach conditions, having a cosmopolitan distribution across tropical, subtropical and temperate regions. Herein we provide an overview of published works relating to the fungi of sandy beaches, focusing on the past half-century. We outline a broad range of topics in ecology including fungal adaptive traits to intertidal conditions at the morphological and genetic levels, temporal and spatial patterns in community structure, and species variations in substrate preference. Collectively, these concepts should encourage marine mycologists to embrace a holistic set of perspectives to shape the outlook for beach ecology.     

Wrack promotes the persistence of fecal indicator bacteria in marine sands and seawater

Algae on freshwater beaches can serve as reservoirs for fecal indicator bacteria (FIB). Wrack (especially kelp) at marine beaches might sustain FIB as well. This study examines the relationship between beach wrack, FIB, and surrounding water and sediment at marine beaches along the California coast. Surveys of southern and central California beaches were conducted to observe environmental wrack-associated FIB concentrations. FIB concentrations normalized to dry weight were the highest in stranded dry wrack, followed by stranded wet and suspended 'surf' wrack. Laboratory microcosms were conducted to examine the effect of wrack on FIB persistence in seawater and sediment. Indigenous enterococci and Escherichia coli incubated in a seawater microcosm containing wrack showed increased persistence relative to those incubated in a microcosm without wrack. FIB concentrations in microcosms containing wrack-covered sand were significantly higher than those in uncovered sand after several days. These findings implicate beach wrack as an important FIB reservoir. The presence of wrack may increase water and sediment FIB levels, altering the relationship between FIB levels and actual health risk while possibly leading to beach closures. Further work will need to investigate the possibility of FIB growth on wrack and the potential for pathogen presence.     

Impact of marine heatwaves for sea turtle nest temperatures

There are major concerns about the ecological impact of extreme weather events. In the oceans, marine heatwaves (MHWs) are an increasing threat causing, for example, recent devastation to coral reefs around the world. We show that these impacts extend to adjacent terrestrial systems and could negatively affect the breeding of endangered species. We demonstrate that during an MHW that resulted in major coral bleaching and mortality in a large, remote marine protected area, anomalously warm temperatures also occurred on sea turtle nesting beaches. Granger causality testing showed that variations in sea surface temperature strongly influenced sand temperatures on beaches. We estimate that the warm conditions on both coral reefs and sandy beaches during the MHW were unprecedented in the last 70 years. Model predictions suggest that the most extreme female-biased hatchling sex ratio and the lowest hatchling survival in nests in the last 70 years both occurred during the heatwave. Our work shows that predicted increases in the frequency and intensity of MHWs will likely have growing impacts on sea turtle nesting beaches as well as other terrestrial coastal environments.     

The syn-volcanic Naajaat lake, Paleocene of West Greenland

The Naajaat lake in the Nuussuaq Basin on Disko and Nuussuaq formed in a geological setting between cratonic crystalline Precambrian rocks overlain by Cretaceous sediments and an actively forming Paleocene volcanic province. The lacustrine deposits, shales as well as hyaloclastite breccias, accumulated in low-lying areas inundated by fresh water and sealed off from marine transgressions by a broad subaerial volcanic terrain. Foreset-bedded hyaloclastite breccias demonstrate water depths of up to 450 m, and the area of the lake was 2500 km² at its maximum extent. The lake probably existed for less than 0.5 million years. The lake received clay and silt from two provenance areas. Quartz contents of more than 25% in the majority of the sediment samples indicate that large amounts of material were continuously supplied to the lake from the crystalline terrain, whereas the volcanic terrain supplied smectite and mixed-layer minerals to the lake. High kaolinite contents stem from the crystalline or both provenance areas. The shales are characterized by high TOC (up to 11%), lack of pyrite, presence of terrestrial spores and pollen and lack of marine dinoflagellates. The lacustrine sediments rest on an erosional unconformity and its correlative conformity. The unconformity developed during the latest Cretaceous and Early Paleocene. Five stages are recognized in the geological development of the lake. Stages 1–4 are characterized by accumulation of hyaloclastite breccias, rise in lake level, and eventual transgression of subaerial terrains. The rises in lake level were caused by stemming of fluvial run-off behind the aggrading volcanic pile. Stage 5 corresponds to cessation of volcanic activity, a stable lake level, and progradation of clastic sediments, resulting in infilling of the lake. During the lacustrine transgression only sediment in suspension was transported into the central parts of the lake.     

Facies analysis and depositional environments of the Taulanne Limestone Formation in the South Alpine Foreland Basin (Oligocene, southeastern of France)

The Taulanne Limestone Formation of the Castellane region (South Alpine Foreland Basin of France) represents an Oligocene lake depositional system developed above the marine Nummulitic succession. A sedimentological analysis of the Taulanne limestone allows the identification of nine marine, lacustrine, and palustrine facies. The spatial and temporal distribution of these facies records five depositional sequences that are correlated between the Sant Peire section (edge of the lake) and the Prés section (central lake). Water-level variations highlight the high-frequency balance between drying and wetting periods under fluctuating climatic conditions. Lacustrine facies developed during more humid periods while palustrine facies correspond to more arid conditions and longer lake shoreline exposure. At the basin scale, the lateral changes in accommodation space are attributed to differential subsidence between the Prés and the Sant Peire sections, which permitted the deposition of a thicker succession in the central part of the lake (Prés section). The Taulanne limestone records a marine to continental transition. The progressive filling of the basin is related to the regional tectonic activity, namely the emplacement of the Embrun-Ubaye nappes to the northeast of the study area at about 30–32 Ma. This final regressive trend represents the transition between the underfilled flysch stage (marine Nummulitic succession) of a foreland-basin cycle to the overfilled stage (alluvial Red Molasse deposits) during the primary exhumation of the Internal Alps.     

Hesionides riegerorum n. sp., a New Interstitial Freshwater Polychaete from the United States

Hesionides riegerorum n. sp. is a new freshwater polychaete species. It was found in considerable numbers in the interstitial habitat of sandy banks of the Chowan River in North Carolina, USA. There are no general differences in the organization and behavior compared to the marine species of this genus. The new species, however, is unequivocally distinguished from them by slight quantitative differences and more striking qualitative features. The localities not far from the coast point to an immigration path for this freshwater polychaete that has been shown also for most of the other marine interstitial immigrants: directly from sandy intertidal beaches along brackish estuaries into the limnopsammal.     

Persistence, dissipation, and activity of Escherichia coli O157:H7 within sand and seawater environments

Runoff from agricultural land into watercourses may transport and deposit animal-derived waste contaminated with Escherichia coli O157:H7 onto beaches, which may in turn lead to human infection. To simulate contamination, freshwater mixed with cattle slurry containing E. coli O157:H7 was added to sand from three recreational beaches. The sand was then maintained in a dry state (nontidal) or subjected to a repeated seawater tidal simulation. The pathogen could still be recovered from all sands by day 5. Although survival of the pathogen did not statistically vary between sands of different origin under nontidal conditions, significant differences in numbers occurred between sands when subject to tidal simulation. In the tidal simulations, a considerable proportion of the E. coli O157:H7 rapidly dissipated from sand into the seawater. In a separate experiment, the activity of bioluminescent (lux-marked) E. coli O157:H7 cells was monitored in various mixtures of contaminated runoff water and seawater over 5 days. Pathogen activity declined with increasing seawater concentration; however, cells remained viable in all treatments over the 5-day period. The addition of nutrients to water rapidly increased pathogen activity in all treatments. Our findings highlight the resilience of E. coli O157:H7 in aquatic and marine environments.     

Fungi from decaying intertidal fronds of Nypa fruticans, including three new genera and four new species

HYDE, K. D., 1992. Fungi from decaying fronds of Nypa fruticans, including three new genera and four new species. Decaying fronds and exposed stems of the mangrove palm Nypa fruticans were collected from beaches and intertidal regions of mangroves in Brunei and examined for the presence of higher marine fungi. Forty-three species were identified, four of which are new to science. The fungi included 32 Ascomycotina, one Basidiomycotina and ten Deuteromycotina. Three new genera and four new species are described and illustrated.     

Temporal spatial distribution of benthic meiofauna in four beaches of the northern Havana shore

The temporal-spatial distribution of benthic meiofauna was evaluated in four beaches at the north coast of Havana, Cuba, from March 2003 to February 2004. We studied two urban beaches (Santa Fe and La Concha) and two tourist beaches (Mar Azul and Canasi). Monthly meiofauna samplings were taken by scuba-diving using with a syringe (inner diameter 2.5 cm), and physico-chemical parameters (grain size, interstitial salinity and water column salinity were recorded with standard equipment). Statistical analysis (MDS and ANOSIM) were performed. Depth and biotope kind were the same in the four beaches. Highest densities were obtained in Santa Fe (7,133.48 ind/10 cm2) while the lowest mean densities were found in Canasí (892.12 ind/10 cm2). We recorded 13 taxa; the dominant organisms in Santa Fe and Mar Azul were free-living marine nematodes. Copepods were the dominant organisms in La Concha and Canasí.