Dispersion of gastrotricha in a marine beach of the San Juan Archipelago,Washington

Gastrotricha were quantitatively sampled at low tide on several dates from two transeets at Eagle Cove, San Juan Island, Washington, USA, during the summers of 1963/1964. They showed low species diversity and very high whole-beach densities. Chaetonotus testiculophorus Hummon, 1966 and Turbanella cornuta Remane, 1925 were found abundantly, Paraturbanella intermedia Wieser, 1957 only rarely. Abundant C. testiculophorus were found above 100 cm elevation; T. cornuta occurred abundantly in a rip-channel trough and in the lower beach area. T. cornuta, but not C. testiculophorus, showed significantly greater clumping at high than at low density. Curves of LC₉₀ temperature-salinity tolerance for both species show that they tolerate widely fluctuating temperatures and salinities. Causes of whole-beach distribution patterns are discussed.Research was supported by an NSF College-University Association Grant (G-17537), administered by the Graduate School, University of Washington, Seattle, and was conducted at the Friday Harbor Laboratories, San Juan Island, Washington, during the summers of 1963 and 1964.     

Diel and seasonal changes in the distribution of fish on a southeast Brazil sandy beach

The effect of diel and seasonal changes in the distribution of fishes on a subtropical sandy beach on the southeastern coast of Brazil were studied. Seine netting was carried out on both seasonal and diel scales between July 1998 and June 1999. A total of 46 fish species was recorded, six being numerically dominant: Anchoa tricolor, Gerres aprion, Harengula clupeola, Atherinella brasiliensis, Mugil liza and Diapterus rhombeus. Seasonal changes in abundance of dominant species were detected. Species dominant in winter were Anchoa tricolor, H. clupeola and Atherinella brasiliensis; in spring, Anchoa tricolor and G. aprion; in summer G. aprion and D. rhombeus; and in autumn M. liza and H. clupeola. Overall, diel patterns did not reveal any significant trends; however, if we consider each season separately, an increase in A. tricolor abundance was recorded during the day in winter/spring, being replaced at night by H. clupeola in winter, and by G. aprion in spring. Increases in number of individuals and biomass at sunset, and decreases during the night were recorded. The winter/spring inshore/offshore movements at diel scale performed by the three most abundant species demonstrate that diel fluctuation acts more at a species-specific level than at a structural one; in summer there was no evidence of diel movements due to a heavy influx of G. aprion and D. rhombeus, which use the area throughout day and night, increasing overall abundance. Seasonal movements seems to be related to ontogenetic change in species, while diel movements in the fish assemblage seem to be more related to physiological requirements, such feeding activity of each particular species, than to physico-chemical conditions.Communicated by O. Kinne, Oldendorf/Luhe     

Distribution of the marine littoral Foraminifera in Argentina,Uruguay and Southern Brazil

Benthic foraminifers collected in the marine littoral zone (sensu lato) of Argentina, Uruguay and Southern Brazil have been studied and compared with the Foraminifera collections from the same area studied previously. Two figures have been prepared, which show the geographical range and relative abundance of the most important species (cosmopolitan and non-cosmopolitan). The following biogeographical conclusions were drawn on the basis of an analysis of these figures. The whole area, from a latitude of about 32° S up to the southern coast of Tierra del Fuego, should be considered as one biogeographical unit (a kingdom of Buccella peruviana, sensu lato). This unit has 2 internal boundaries, which are located approximately at latitudes 41° and 52° S. They divide the whole area into 3 sub-areas which can be called (from North to South): North Patagonian (32° to 41° S), South Patagonian (41° to 52° S) and Malvinian (52° S—southern coast of Tierra del Fuego). With the exception of Buccella peruviana, sensu lato, which is typical of all 3 sub-areas, these sub-areas are characterized by the following faunal features. The North Patagonian sub-area contains abundant numbers of Elphidium discoidale. The South Patagonian sub-area is characterized by abundant numbers of Elphidium macellum. The Malvinian sub-area contains abundant numbers of Elphidium macellum, and also several very typical representatives of the Malvin current water, for instance, Cassidulina crassa, sensu stricto, Angulogerina angulosa, Uvigerina bifurcata, Cassidulinoides parkerianus, Ehrenbergina pupa and others. It is a matter of opinion whether the sub-areas cited be considered biogeographical sub-provinces, or even smaller units. They cannot be interpreted as biogeographical provinces.Contribution No. 62 of the Puerto Deseado Marine Biological Station.     

A policy alternative for lagoon management: case study of Sre Ambel coastal marine fisheries,Cambodia

Sre Ambel is the most productive coastal area for marine fisheries in Cambodia. This paper explores the management concept of extractive reserve instruments to find the most effective application in the coastal areas of Cambodia. Since there are various extractive models in the world, the most important objective is to determine which extractive reserve model is best suited to real practices where the ability of the fisheries’ residents to apply laws and guidelines vary from one place to another. To reflect these objectives, this paper looks at various examples around the world, especially from various Latin American countries. The level of local ability to apply laws and regulations is determined by the weight average index method. These results shows that fishers’ education levels are sufficient to apply laws and regulations, but their understanding of existing fisheries guidelines is still below average. Although the level to which they satisfy the guidelines is poor, local people are willing to establish new appropriate guidelines for future effective application. Therefore, local fishers have the ability to apply laws and regulations under new extractive reserve aspects. An extractive reserve policy combines all available instruments to manage the lagoon. The best alternative is to develop strong collaboration among the various stakeholders in the area. This converts an open-access to common property resource use regime. All instruments of extractive reserve were satisfied by the local fishers. However, extractive reserve seems to be similar with fish refuge concept which currently proposed by Southeast Asian Fisheries Development Centre (SEAFDEC).     

Salinity effects on the coexistence of cryptic species: a case study on marine nematodes

The coexistence of four cryptic species of Rhabditis (Pellioditis) marina (Nematoda: Rhabditidae) at small geographical scale challenges ecological competition theory and was therefore studied in the laboratory at two different salinities, where their performance in combined cultures was compared with that in monospecies cultures. We found that three of the four cryptic species were able to coexist, but that interspecific interactions (competition and facilitation) were common. Salinity had an effect on these interactions, with a shift from contest to scramble competition. This shift may result from an increased population development of two of the four species at the lower salinity in the monospecific cultures. This experiment demonstrates that abiotic conditions may play an important role in achieving coexistence between cryptic species and can alter the interspecific interactions between them.     

污灌区土壤-小麦系统重金属污染、迁移和积累--以开封市化肥河污灌区为例

以开封市化肥河污灌区为例，研究了土壤-小麦系统重金属(Cd、Pb、Cr、Cu、Zn、Ni和AS)污染、迁移和积累规律。结果表明，该区土壤重金属污染较为严重，所有样点的综合污染指数均大于1，其中Cd和AS污染最为严重，其平均质量分数远远超出了土壤环境二级标准值。在该区土壤上种植的小麦也表现出一定程度的重金属累积，但其茎叶和种子重金属质量分数差别较大；在所有种子样品中，Zn质量分数都未超标，AS、Cr和Pb质量分数部分到达了较高的残留水平，Cd质量分数则远远超出了国家食品限量卫生标准。依据重金属迁移累积率(βi)，小麦对As和Cr的吸收能力较低，而对Ni和Cd的吸收能力较高；在所有小麦样品中，除Cu外，茎叶对同一重金属的平均富集能力均大于种子。     

Model-based analysis of the influence of ecological processes on forest point pattern formation—A case study

Many different spatio-temporal individual-based models (IBM) for forests have been developed for studying the development of trees in space and time. Such models typically depend on various numerical parameters that represent the ecological processes of growth (G), inter-plant competition (C) and birth-and-death (B&D; also called regeneration and mortality). Until now little work has been done to systematically trace the influence of these processes and their model parameters on the spatial structure of forest ecosystems.This paper attempts to fill this gap by addressing an important aspect of forest structure, spatial variability, characterised by the mark variogram as a summary characteristic. The model used was inspired by components of various well-established IBMs including a shot-noise competition field. Time series data from monospecies forests in three different countries of the northern hemisphere provided ecological reference scenarios. Though a case study, the paper's methodology is rather general and can be applied to any model and forest ecosystem.Methods of sensitivity analysis revealed that only a small number of model parameters is crucial for forming spatial variability. Particularly important is the range of competition between trees; with increasing range the variability increases. Growth processes have considerable importance particularly with short observation periods and in young forests, whereas mortality processes become more influential in the long-term. Naturally, these statements depend upon the initial structure and on the length of the observation period.     

Predator-induced morphological defenses in marine zooplankton: a larval case study

While there are numerous reports of predator-induced morphological defenses for freshwater zooplankton, freshwater larvae, and benthic marine animals, a literature search revealed no reports of predator-induced morphological defenses for marine zooplankton. Rarity of predator-induced morphological defenses in marine zooplankton would imply a difference in predation risks compared to those experienced by freshwater organisms and benthic marine adults, whereas the presence of such plasticity in defenses would imply that risks are modified by developmental responses. This study reports a predator-induced change in defenses and vulnerability of a marine planktonic larva. Specifically, when reared in the presence of zoea larvae of Cancer spp., veliger larvae of the intertidal snail Littorina scutulata developed significantly smaller shell apertures and rounder shells than did cohort veligers reared in the absence of predator cues. Pairwise predation trials demonstrated that veligers reared with caged zoeas throughout development had greater survival than predator-naive veligers during short-term exposure to zoeas. The development of predator-induced morphological defenses by some marine larvae introduces a range of testable hypotheses on developmental plasticity that reduces vulnerability of planktonic larvae and other marine zooplankton to predators.     

Growth and spatial distribution of Cassidulus mitis (Echinodermata: Echinoidea) on a sandy beach in Southeastern Brazil

Using a hand dredge, a population of Cassidulus mitis Krau, 1954 was sampled monthly from February 1986 to January 1987 at 15 stations offshore from Vermelha Beach (22°5718 S; 43°948 W), in water depths ranging from 0 to 6 m. The sex ratio indicated a slight numerical dominance of females for adults and a larger numerical female dominance for juveniles. A von Bertalanffy growth curve was estimated as L=71.00 (1-e^(-0.390t)), where L=length (mm) and t=time (yr). The instantaneous natural mortality rate (M) was estimated as 0.812. The population occupies a zone parallel to the beach, and displays a spatially aggregated pattern, with higher densities in areas characterized by coarse and very well sorted sand containing low amounts of organic matter.     

Implications of mangrove dynamics for private and use in bragança, north Brazil: a case study

This work analyses effects of recent variations in the tidal inundation frequency in a mangrove ecosystem in the Bragança peninsula, North Brazil, and its implications for land occupation and use. Field data, time series of remote sensing images and local legislation were analysed focusing on the potential socio-economic impact of a changing environmental setting due to a rise in relative sea level. In the investigated period (1972–1997), vegetation changes along the coastline indicate net losses of mangrove coverage. In the central part of the peninsula, a topographically higher herbaceous plain constituting part of a farm presents an active progression of mangrove forest into an area previously dominated by grasses and herbs. This area measured 8.8 km² in 1972 but was gradually reduced to 5.6 km² in 1997, while progressively replaced by a monospecific stand of the black mangrove,Avicennia germinans. A linear extrapolation indicates that the elevated plain may be completely covered by mangrove by 2035. Current Brazilian legislation prohibits the extraction of mangrove trees without an officially approved management plan. Thus, the usable area of the farm has suffered a reduction by ca. 36% over 25 yr and we predict that is could be entirely replaced by mangroves in the next 35 yr. In this case study, legislation and ecosystem characteristics are analysed and a management plan discussed which could represent income alternatives for affected resource users at the local and regional level.     

Identifying factors that influence soil heavy metals by using categorical regression analysis: A case study in Beijing,China

A method was proposed to identify the main influence factors of soil heavy metals. The influence degree of different environmental factors was ranked. Parent material, soil type, land use and industrial activity were main factors. Interactions between some factors obviously affected soil heavy metal distribution. Identifying the factors that influence the heavy metal contents of soil could reveal the sources of soil heavy metal pollution. In this study, a categorical regression was used to identify the factors that influence soil heavy metals. First, environmental factors were associated with soil heavy metal data, and then, the degree of influence of different factors on the soil heavy metal contents in Beijing was analyzed using a categorical regression. The results showed that the soil parent material, soil type, land use type, and industrial activity were the main influencing factors, which suggested that these four factors were important sources of soil heavy metals in Beijing. In addition, population density had a certain influence on the soil Pb and Zn contents. The distribution of soil As, Cd, Pb, and Zn was markedly influenced by interactions, such as traffic activity and land use type, industrial activity and population density. The spatial distribution of soil heavy metal hotspots corresponded well with the influencing factors, such as industrial activity, population density, and soil parent material. In this study, the main factors affecting soil heavy metals were identified, and the degree of their influence was ranked. A categorical regression represents a suitable method for identifying the factors that influence soil heavy metal contents and could be used to study the genetic process of regional soil heavy metal pollution.     

“非正常”凋落物对冰雪灾后南岭森林土壤有机碳的影响

2008年初,一场百年罕见的冰雪灾害袭击了我国南方地区,对南方19个省（区）的林区,相当中国森林面积的13%（1.86×107 hm2）的森林植被遭受整体性、毁灭性破坏,导致的大量“非正常”凋落物必将对森林土壤碳循环产生深远影响。本研究以广东乐昌杨东山十二度水省级自然保护区不同海拔梯度上受灾的常绿阔叶混交林3种森林群落为研究对象,采用去除冰雪灾害导致的“非正常”凋落物与受损林地进行对照试验,对冰雪灾害所导致“非正常”凋落物对土壤碳的影响进行了研究。研究结果表明：灾后3种森林群落中不同深度土壤的有机碳质量分数和储量持续增加,同一深度土壤有机碳质量分数和碳储量在不同年份之间差异显著。直至2011年“非正常”凋落物分解完毕时,10~50 cm的土壤有机碳质量分数与上一年相比有减少趋势;0~10 cm的土壤有机碳质量分数稍比2010年高,但变化差异不显著(p=0.36),说明在“非正常”凋落物分解结束后土壤有机碳质量分数有减小的趋势,致使土壤碳储量下降。去除“非正常”凋落物样地与对照样地相比,各土壤深度的土壤有机碳质量分数明显下降,年平均下降百分比例变化范围为12.14%~55.34%,0~10 cm和10~30 cm土壤的有机碳质量分数下降变化波动幅度要比30~50 cm大;不同深度土壤有机碳质量分数与凋落物有机碳失质量间具有显著的线性相关性。可见,冰雪灾害导致的“非正常”凋落物对土壤有机碳质量分数和储量都有十分显著的影响,“非正常”凋落物的分解输入能显著提高土壤有机碳质量分数和储量。     

An analysis of beach management framework in Spain. Study case: the Catalonian coast

In the present paper, the current beach management framework in the North-Western Mediterranean coast (Catalonia, Spain) was revised. Beach management was analyzed using the concepts of Integrated Coastal Zone Management (ICZM). The history of beach management in the second half of the 20 century and the new developments in the academic field and in the practical beach management sector during the last decade were studied. The revision of legal texts and strategies in the Catalan coast allowed synthesizing all scattered information affecting beach management. A SWOT analysis was performed. The main strengths of the beach management framework in Catalonia are the public ownership of beaches, which allows the government to carry out a comprehensive management and the recent data and analysis provided by the adopted National and Autonomous ICZM strategies. The weaknesses found were related to the functioning of traditional existing institutions. New opportunities are related to the possibility of establishing new institutions that conduct a more inclusive and proactive management. The main threat is that although the possibility for a fundamental change in beach management organization exists, resources available are not fully exploited.     

Bacterial communities of the marine sponges Hymeniacidon heliophila and Polymastia janeirensis and their environment in Rio de Janeiro, Brazil

In this study we performed a survey of the bacterial communities associated with the Western Atlantic demosponges Hymeniacidon heliophila and Polymastia janeirensis, based on 16S rRNA sequencing and transmission electron microscopy (TEM). We compared diversity and composition of the sponge-associated bacteria to those of environmental bacteria, represented by free-living bacterioplankton and by bacteria attached to organic particulate matter in superficial sediments. Partial bacterial 16S rRNA sequences from seawater, sediment, and sponges were retrieved by PCR, cloning, and sequencing. Sequences were subjected to rarefaction analyses, phylogenetic tree construction, and LIBSHUFF quantitative statistics to verify coverage and similarity between libraries. Community structure of the free-living bacterioplankton was phylogenetically different from that of the sponge-associated bacterial assemblages. On the other hand, some sediment-attached bacteria were also found in the sponge bacterial community, indicating that sponges may incorporate bacteria together with sediment particles. Rare and few prokaryotic morphotypes were found in TEM analyses of sponge mesohyl matrix of both species. Molecular data indicate that bacterial richness and diversity decreases from bacterioplankton, to particulate organic sediment, and to H. heliophila and P. janeirensis. Sponges from Rio de Janeiro harbor a pool of novel and exclusive sponge-associated bacterial taxa. Sponge-associated bacterial communities are composed of both taxons shared by many sponge groups and by species-specific bacteria.     

A comparative study of the glutamate dehydrogenase activity in several species of marine phytoplankton

Kinetic studies on the NADP-linked glutamate dehydrogenase (GDH) activity in 8 species of marine phytoplankton have been carried out. The pH optima, linearity of reactions, apparent energies of activation, and apparent K _m values for NADPH, NH ₄ ^>+ and -ketoglutarate were determined. Based on these data, an accurate, sensitive enzyme assay procedure is presented which was successfully tested on shipboard during a recent cruise in an upwelling region. Preliminary studies on inhibition and activation of the NADP-linked GDH activity have also been carried out. In addition to NADP-linked GDH activity, NAD-linked GDH activity was discovered in certain species of phytoplankton. The possible physiological roles of NAD-and NADP-linked GDH enzymes are discussed.Contribution No. 911 from the Department of Oceanography, University of Washington. This research was supported by the National Science Foundation Grants GA-34165 and GX-33502.     

Ecotypic differentiation in the marine diatom Skeletonema costatum: influence of light intensity on the photosynthetic apparatus

Three genetically distinct clones of Skeletonema costatum (Grev.) Cleve were grown at 20°C under high (274 E m^-2 s^-1) and low (27 E m^-2 s^-1) light conditions and their photoadaptive photosynthetic responses compared. When all three clones were grown under low light, pigment analyses and fluorescence excitation spectra demonstrated that the accessory pigments, chlorophyll c and fucoxanthin, became more important in light-harvesting compared to chlorophyll a. Photosynthetic unit sizes increased for Photosystems I and II in low light, but photosynthesis vs irradiance characteristics were not reliable predictors of photosynthetic unit features. Fluorescence excitation spectra and photosynthesis vs irradiance (P-I) relationships indicated that changes in energy transfer occurred independent of changes in pigment content. Large increases in accessory pigment content were not accompanied by large increases in excitation from these pigments. Changes in energy transfer properties were as important as changes in PSU size in governing the photoadaptive responses of S. costatum. When the three clones were grown under identical conditions, each had a separate and distinct pattern of photoadaptation. Significant differences among clones were found for pigment ratios, photosynthetic unit sizes for Photosystems I and II and efficiency of energy transfer between pigments. These strikingly different photoadaptive strategies among clones may partially account for the great ecological success of the diatom species. This is the first quantitative investigation of the importance of both chlorophyll c and fucoxanthin to the adaptive responses of diatoms to light intensity, and represents the most complete characterization of the photoadaptive responses of a single species of marine phytoplankter to differences in light environment.     

Dehydrogenases as tools in the study of marine sediments

A method is outlined for the measurement of NADH₂-dependent dehydrogenase activity in whole samples as well as in fractions of carbonate sediments. The method is based on extraction of enzyme activity with phosphate buffer containing 0.12% Triton X-100, dialysis, and a photometric assay which permits initial velocity determinations of the enzyme reaction under controlled conditions of pH, temperature, and substrate concentration. The dehydrogenases extracted from carbonate sediment of a subtropical beach at Bermuda are characterized by low K _m values (0.03 to 0.07 mM NADH₂/1), pH maxima around 8.5, and temperature maxima between 35° and 40°C. Their vertical distribution in the sediment agrees with what is known about the distribution of biomass on beaches of this type, maximum activity occurring in the topmost centimetre. Approximately 80 to 90% of the total electron transport activity is contained in the grain fraction, the remainder in the interstitial fraction of a sediment sample. From this it can be inferred that the interstitial fauna contributes only little to the total energy budget of this type of sediment, which is dominated by the Aufwuchs on the sand grains. The electron transport activity (ETA) measured by means of the dehydrogenase assay is taken to represent the maximum transport capacity (ETC) of all the organisms living in the sand ecosystem. From published evidence it is inferred that oxygen consumption of sediment samples and of individual organisms measured in vivo usually accounts for 10 to 20% of the maximum electron transport capacity measured in vitro with saturating concentrations of substrates and with Triton X-100 as part of the enzyme assay. It is suggested further that the ratios of dehydrogenase activities in different fractions or zones of sediment, or of different organisms, may represent one of the best indicators, so far available, of energy relationships in marine sediments.Contribution No. 652 from the Bermuda Biological Station for Research.     

Development and case study of a new-generation model-VAT for analyzing the boundary conditions influence on atmospheric mercury simulation

Atmospheric models are essential tools to study the behavior of air pollutants. To interpret the complicated atmospheric model simulations, a new-generation Model Visualization and Analysis Tool (Model-VAT) has been developed for scientists to analyze the model data and visualize the simulation results. The Model-VAT incorporates analytic functions of conventional tools and enhanced capabilities in flexibly accessing, analyzing, and comparing simulated results from multi-scale models with different map projections and grid resolutions. The performance of the Model-VAT is demonstrated by a case study of investigating the influence of boundary conditions (BCs) on the ambient Hg formation and transport simulated by the CMAQ model over the Pearl River Delta (PRD) region. The alternative BC options are taken from (1) default time-independent profiles, (2) outputs from a CMAQ simulation of a larger nesting domain, and (3) concentration files from GEOS-Chem (re-gridded and re-projected using the Model-VAT). The three BC inputs and simulated ambient concentrations and deposition were compared using the Model-VAT. The results show that the model simulations based on the static BCs (default profile) underestimates the Hg concentrations by ~6.5%, dry depositions by ~9.4%, and wet depositions by ~43.2% compared to those of the model-derived (e. g. GEOS-Chem or nesting CMAQ) BCs. This study highlights the importance of model nesting approach and demonstrates that the innovative functions of Model-VAT enhances the efficiency of analyzing and comparing the model results from various atmospheric model simulations.

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A flume study of drift in marine infaunal amphipods (Haustoriidae)

Amphipods of the infaunal family Haustoriidae are characteristic of high-energy marine sands and occur both in the sediment and the overlying water column. Sediments in this habitat are subject to constant reworking by tidal currents, suggesting that resident amphipod populations are affected by this disturbance in a phenomenon similar to freshwater invertebrate drift. A controlled-velocity laboratory flume was used to examine the effect of haustoriid density, current velocity, illumination, and food availability on drift rates to determine a causal basis for drift. Drift is densityindependent and greatest at night and during high current flow; it is also greater at night from sterile sediment than from untreated sand. Flume transport was usually less than 10% of amphipods present in the sediment. Haustoriids captured downstream were mostly adults occurring in a 1:1 sex ratio, suggesting no obvious function of drift in reproduction. Current-induced displacement of haustoriids may produce the patchiness in distribution observed in nature. Disturbance of the bed could also function to keep amphipod densities below the carrying capacity of the local environment. In certain cases, food limitation may cause amphipods to actively leave the substrate. Under all conditions, greater drift rates in darkness are probably adaptive in avoidance of predators. Despite the nature of sediment movement in a high-energy environment, haustoriid drift may have an active as well as passive component.