Linking hypoxia to shrimp catch in the northern Gulf of Mexico

Wide spread and reoccurring hypoxia has been observed in the northern Gulf of Mexico since routine monitoring began in the 1980s. Although the potential ecological effects of hypoxia (habitat loss, mortalities) are well known, there is relatively little information linking hypoxia in the northern Gulf of Mexico to fisheries decline. Previous analyses have shown a negative relationship between hypoxic area and brown shrimp (Farfantepenaeus aztecus) catch for the Texas and Louisiana coasts combined from 1985 to 1997. Extending these analyses with data through 2004, we found that the correlation between hypoxic area and landings holds (r=-0.52), plus there was a significant negative relationship (r=-0.59) between hypoxia and shrimp landings for the Texas coast alone. We hypothesize that this pattern is not seen in the Louisiana fishery alone because of differences in fisheries practices (inshore vs. offshore) between Louisiana and Texas.     

Assessment of water and bottom sediment conditions in the bights of Koz’mina and Lake Vtoroe (Nakhodka Gulf,Peter the Great Bay,the Sea of Japan)

The state of the water area in the Bays of Koz’mina and Lake Vtoroe (Nakhodka Gulf is evaluated. The data given include water temperature and salinity, biochemical oxygen demand, pH, alkalinity, chlorophyll a, organic matter, biogenic elements, oil products, detergents, polycyclic aromatic hydrocarbons, phenols, and organochlorine pesticides in water and bottom sediments. Pollutants may enter the system of bights from both onshore sources and the open part of the bay. The water and bottom sediments in this part of the bay show higher values of BOD5 and the concentrations of oil products, polycyclic aromatic hydrocarbons, phenols, and organochlorine pesticides. The anthropogenic load on the water body is shown to increase because of the new industrial construction on its shore.     

Pesticides Removal Using Conventional and Low‐Cost Adsorbents: A Review

Worldwide pesticide usage has increased dramatically during the last three decades, coinciding with changing practices and increasing by intensive agriculture. This widespread use of pesticides for agricultural and non‐agricultural purposes has resulted in the presence of their residues in various environmental matrices. The occurrence of pesticides and their metabolite transported in rivers, channels, lakes, sea, air, soils, groundwater, and even drinking water, proves the high risk of these chemicals to human health and the environment. Therefore, pesticide removal is of an increasing concern. In this study, a review of the published literature dealing with pesticides removal process is presented. Firstly, pesticide removal by conventional means is briefly considered. Secondly, the use of the low‐cost sorbent through biosorption process is discussed comprehensively. The effect of factors such as pH, contact time, sorbent dosage, initial pesticide concentration, and optimization of biosorption conditions is also discussed. Kinetic, thermodynamic, and mechanism studies are also given. This study shows that both microorganisms and other materials with biological origin like agricultural by‐products may be used to this end. There is a significant potential for pesticide uptake by the use of various pristine and especially modified biosorbents. In the case of living organisms used as removal agents, degradation may also play a role in the total removal observed.     

Agricultural Chemicals and Ground Water Quality - Issues and Challenges

Anthropogenic agricultural chemicals of concern in ground water include nitrate and pesticides. Increased legislation and regulation of contaminant levels in ground water can be expected. Ground water contamination should be prevented from getting worse, but more research is necessary so as to base regulations on sound criteria. Health effects and acceptable risks must be better formulated. More research on chemical movement in the vadose zone is necessary for accurate predictive modeling of pesticide transport to ground water. Best management practices need to be developed so that farmers will be able to farm profitably while complying with regulations for maximum contaminant levels in underlying ground water. People from all concerned disciplines, citizens'groups, and policy-makers need to work together to develop realistic regulatory policies and management practices that will effectively protect public health while ensuring a viable and sustainable agriculture.     

Presence of DDT and Lindane in a Karstic Groundwater Aquifer in Yucatan,Mexico

Pollution caused by pesticides is becoming relevant because of their harmful environmental effects. The persistence, bioaccumulation and toxicity of some organochloride pesticides have resulted in their restricted use since 1970 and a requirement to monitor them in many countries. Pesticides have endocrine, immunological, reproductive and carcinogenic effects in both humans and animals. The facilitated infiltration of substances results in the pollution of hydric underground resources in karstic limestone such as that found in the state of Yucatan. Observing the north occidental region of the state of Yucatan is particularly important as it is characterized by agricultural activities (wide use of pesticides), significant human settlements and underground water flows oriented towards the north coast. In this study, the underground water quality of a karstic aquifer was evaluated by quantifying the presence of organochlorine pesticides in 29 wells located throughout the Mérida‐Progreso transect, Yucatan, Mexico. The presence of DDT, lindane and their metabolites was detected at concentrations above the permissible limits stated by Mexican regulatory standards (NOM‐127‐SSA1‐1994 2010) in the majority of wells studied. Continuous monitoring of the underground hydric resources in this region is therefore essential to raising awareness of pollution risks and the vulnerability of the coastal north to the contamination of the underground water flows.     

Oil pollution on the Egyptian Red Sea coast

A simple weighing method using carbon tetrachloride as solvent was used to survey the dissolved hydrocarbon and tarball levels in the area of the Egyptian Red Sea coast. The area of investigation covers the coastal area from Ras-Gharib down to the port of Qosier during the period from September 1979 to February 1981. This survey confirms the presence of extensive oil pollution in the area, especially at Ras-Gharib and Ras-Shukhair. Minimum concentrations were obtained at Ghardaqa where no dissolved hydrocarbons were detected (i.e. less than 10 μg l^?1) in 1979–1980 but an increase to 20 μg l^?1 in 1981 was recorded. The high levels of pollution recorded in the southern part of the Gulf of Suez are related to the presence of the offshore oil fields, most of which are located at Ras-Gharib.     

The BEAM-project: prediction and assessment of mixture toxicities in the aquatic environment

Freshwater and marine ecosystems are exposed to various multi-component mixtures of pollutants. Nevertheless, most ecotoxicological research and chemicals regulation focus on hazard and exposure assessment of individual substances only, the problem of chemical mixtures in the environment is ignored to a large extent. In contrast, the assessment of combination effects has a long tradition in pharmacology, where mixtures of chemicals are specifically designed to develop new products, e.g. human and veterinary drugs or agricultural and non-agricultural pesticides. In this area, two concepts are frequently used and are thought to describe fundamental relationships between single substance and mixture effects: Independent Action (Response Addition) and Concentration Addition. The question, to what extent these concepts may also be applied in an ecotoxicological and regulatory context may be considered a research topic of major importance, as the concepts would allow to make use of already existing single substance toxicity data for the predictive assessment of mixture toxicities. Two critical knowledge gaps are identified: (a) There is a lack of environmental realism, as a huge part of our current knowledge about the applicability of the concepts is restricted to artificial situations with respect to mixture composition or biological effect assessment. (b) The knowledge on what exactly is needed for using the concepts as tools for the predictive mixture toxicity assessment is insufficient. Both gaps seriously hamper the necessary, scientifically sound consideration of mixture toxicities in a regulatory context.In this paper, the two concepts will be briefly introduced, the necessity of considering the toxicities of chemical mixtures in the environment will be demonstrated and the applicability of Independent Action and Concentration Addition as tools for the prediction and assessment of mixture toxicities will be discussed. An overview of the specific aims and approaches of the BEAM project to fill in the identified knowledge gaps is given and first results are outlined.     

Increase of organochlorines and mercury levels in common guillemots Uria aalge during winter in the southern North Sea

Beached seabirds, mainly common guillemots Uria aalge, were collected on the Belgian coast during winter from 1990 to 1995. Concentrations of total and organic mercury, and of organochlorines (PCBs and pesticides) were determined in muscle, liver and kidney. They were high compared to summer data (up to one order of magnitude), and increased during winter. This increase is not due to changes of total body weight nor polar lipid content, and thus reflects an actual increase of the seabirds' contamination while wintering in the southern North Sea. The observed annual cycle can be understood by assuming differences in prey contamination: higher during winter in the southern North Sea ecosystem than during summer in the Atlantic water ecosystem.     

Leaching Potential of Turf Care Pesticides: A Case Study of Long Island Golf Courses

Pesticides used to maintain golf course turf can threaten ground water. This concern is particularly important in most of New York's Long Island, where generally sandy soils overlie a sole source aquifer. This study uses two methods to evaluate the potential for pesticides that are commonly used on Long Island's golf courses to leach to ground water.
Adapting the Pesticide Root Zone Model (PRZM). Release 1. for dense turf and applying site-specific soil data, certain pesticides, including metalaxyl and trichlorfon, are identified as potential problem leachers. PRZM simulations also identify the Long Island soils, including the sandy Plymouth and Carver soils, which arc most vulnerable to leaching.
When adequate input data for PRZM is unavailable, the ground water ubiquity score (GUS) method may be useful. GUS teachability classifications of pesticides commonly applied on Long Island golf courses, and of pesticides actually detected in ground water samples taken on Long Island, agree with PRZM predictions and the field data. The GUS method is applied to the evaluation of the leaching potential of pesticide degradation products (DCPA, maneb, and mancozeb metabolites), and the degradation products are shown to be a greater threat to ground water than their parent compounds.
These methods are potentially useful in designing ground water monitoring programs and for guiding the pesticide use and selection decisions of golf course managers.     

Impact of South China Sea Cold Surges and Typhoon Peipah on Initiating Cyclone Sidr in the Bay of Bengal

In the present study, an attempt was made to understand the role of South China Sea (SCS) convection associated with northerly cold surges and Typhoon Peipah in initiating Cyclone Sidr in the Bay of Bengal (BoB). The variation of air sea fluxes during the entire history of Cyclone Sidr tracking before its landfall over Bangladesh was also studied. The presence of cold surges in the north SCS associated with heavy rainfall episodes has been noticed at the southern Gulf of Tonkin coast prior to the formation of Typhoon Peipah. Subsequently, these surges migrated south, which resulted in intensification of a deep convection on reaching the Vietnamese coast. During the same period in the western Pacific, Typhoon Peipah developed, propagating in the westward direction and entering the SCS. Analysis of geostationary water vapour images, mean sea level pressure, and surface wind maps clearly depicted the transport of convective cloud clusters, moisture, and westward momentum from Typhoon Peipah to the deep convection cells over the SCS. Consequently, the existing deep convection over the Vietnamese coast resulted in a westward direction and entered the Gulf of Thailand and Andaman Sea. The availability of higher latent heat fluxes, warmer sea surface temperatures, and suitable atmospheric conditions over this region favoured the formation of a tropical depression in the Andaman Sea. This depression further intensified in the southeast BoB, resulting in the formation of Cyclone Sidr. NCEP/NCAR wind fields and air-sea fluxes revealed left asymmetry surface winds and higher latent heat flux on the left side of the track during the intensification phase of Sidr.     

Effects of new antifouling compounds on the development of sea urchin

Tributyltin oxide (TBTO) has been used worldwide in marine antifouling paints as a biocide for some time. However, it produced toxic effects, especially in marine water/sediment ecosystems. Consequently, its use in antifouling paints has been prohibited in many countries. In this study, the toxicity of alternative and/or new antifouling biocides compared with TBTO is assessed by a biological method. The effects of these chemicals on marine species have not been well studied. This paper assesses, comparatively, the effects of eight biocides on sea urchin eggs and embryos. The chemicals assessed were TBTO, Irgarol 1051, M1 (the persistent degradation product of Irgarol), Diuron, zinc pyrithione, 'KH101', 'Sea-Nine 211', and copper pyrithione. For these chemicals, toxicity appears to be in the order zinc pyrithione > Sea-Nine 211 > KH101 > copper pyrithione > TBTO > Diuron approximately = Irgarol 1051 > M1. Here, we show that zinc pyrithione, Sea-Nine 211, KH101, and copper pyrithione are much more toxic to sea urchins than TBTO or the other chemicals.     

Using growth measures in the freshwater shrimp Caridina nilotica as biomarkers of Roundup® pollution of South African freshwater systems

There has been global concern about the effect of toxic chemicals on aquatic biota due to the upsurge in contamination of aquatic ecosystems by these chemicals, which includes pesticides. Roundup® and other glyphosate-based herbicides are frequently used in the chemical control of weeds and invading alien plant species in South Africa. These bio-active chemicals ultimately get into water courses directly or indirectly through processes such as drifting, leaching, surface runoff and foliar spray of aquatic nuisance plants. However, there is no South African water quality guideline to protect indigenous freshwater non-target organisms from the toxic effects of glyphosate-based herbicides. This study evaluated the possible use of growth measures in Caridina nilotica as biomarkers of Roundup® pollution as part of developing glyphosate water quality guideline for the protection of aquatic life in South Africa. Using static-renewal methods in a 25-day growth toxicity test, 40 days post hatch shrimps were exposed to different sub-lethal Roundup® concentrations of 0.0 (control), 2.2, 2.8, 3.4, 4.3 and 5.4 mg/L. Shrimps were fed daily with TetraMin® flake food and test solutions changed every third day. Shrimp total lengths and wet weights were measured every fifth day. These data were used to determine the shrimp’s growth performance and feed utilization in terms of percent weight gain (PWG), percent length gain (PLG), specific growth rate (SGR), condition factor (CF), feed intake (FI), feed conversion ratio (FCR) and feed conversion efficiency (FCE). Moulting was observed for 14 days and the data used to determine the daily moult rate for each concentration. Results of growth performance and food utilization indices showed that growth was significantly impaired in all exposed groups compared to control (p < 0.05). Moulting frequency was also higher in all exposed groups than in control (p < 0.05). Although all the tested growth measures proved to be possible biomarkers of Roundup® pollution, moulting frequency gives a clearer indication of the sub-lethal effects of Roundup® toxicity.     

Achieving a paradigm shift in environmental and living resources management in the Gulf of Guinea: the large marine ecosystem approach

The Gulf of Guinea is situated in the narrow protrusion of eastern Equatorial Atlantic between latitudes 2 degrees S and 5 degrees N and longitudes 8 degrees W to 12 degrees E, spanning a coastline length of approximately 130 nautical miles. The dominant feature of this shallow ocean off the coast of countries in Western Africa is the Guinea Current. The distinctive bathymetry, hydrography, productivity and trophodynamics of this shallow ocean qualify it as a large marine ecosystem (LME) and is indeed recognized as the number 28 of the 64 delineated LMEs globally. This area is one of the world's productive marine areas that is rich in fishery resources, oil and gas reserves, precious minerals and an important global reservoir of marine biological diversity. Unfortunately, pollution from residential and industrial sources has affected the waters of the Gulf of Guinea resulting in habitat degradation, loss of biological diversity and productivity, and degenerating human health. In reversing this trend of marine environmental degradation, the countries of the region adopted an integrated and holistic approach using the LME concept to sustainably manage the environmental and living resources of the region. The concept is predicated on the fact that marine environmental pollution and living resources respect no political or geographical boundaries and so require a holistic and regional approach for its management. The Gulf of Guinea countries through the Global Environment facility funded regional/communal project on water pollution control and biodiversity conservation achieved a paradigm shift in living resources and environmental management in the region using the LME concept.     

Impacts of cyclic hypoxia on reproductive and gene expression patterns in the grass shrimp: field versus laboratory comparison

Identification of organisms able to act as biological indicators of hypoxia exposure is important given the increasing frequency of hypoxic events worldwide. Grass shrimp, Palaemonetes pugio, are ubiquitous estuarine residents in the southeastern US, where they commonly experience cyclic hypoxia. We hypothesized that reproductive and gene expression patterns of grass shrimp in cyclic hypoxic field sites relative to normoxic sites would be similar to previous results from cyclic hypoxia laboratory experiments showing differential up- and down-regulation of hypoxia-responsive genes. There were few differences in gene expression of indigenous shrimp collected during summer from two Gulf of Mexico estuarine systems [East Bay, FL (EB) and Weeks Bay, AL (WB)], although down-regulation of the gene coding for vitellogenin-1 corresponded with a decreased relative fecundity and fewer ovigerous females at cyclic hypoxic field sites, suggesting an overall impact on reproduction. The gene expression profiles of grass shrimp caged for 7 days in field sites differed by estuary, but few hypoxia-responsive genes identified in laboratory studies were differentially expressed in field shrimp. Overall, genes coding for protein synthesis, protein degradation, carbohydrate and lipid metabolism and electron transport were mostly up-regulated in EB caged shrimp but generally down-regulated in WB caged shrimp and laboratory shrimp. Thus, caged grass shrimp from different bay systems exhibited profoundly different gene expression profiles. Such profiles may serve as sensitive bioindicators of differences in water quality, habitat quality or food resources among estuaries but are not effective as indicators of hypoxia exposure.     

Fate of Pesticides and Their Transformation Products: First Flush Effects in a Semi‐Arid Catchment

Although it is known for many years, that transformation products (TPs) of pesticides are often more persistent, mobile, and sometimes more toxic than the parent compound, former catchment scale studies of substance release and flushing effects focused only on the parent compound. In this study, four river points were sampled in the Hula Valley, Israel, and samples were analyzed in the lab for chlorpyrifos (CP) and endosulfan residues (including transformation products; TPs). Sampling results of the first rainfall in autumn 2009 identified a strong release of most substances to the rivers. First flush effects of these substances were assessed regarding the risk for drinking water supply and ecology, like fresh water invertebrates and fish. Although, these substances were found in Jordan River water during the first significant rainfall the observed levels are below international drinking water guideline values with no adverse effects on human health in the region. However, the observed CP and chlorpyrifos oxon (CPO) levels are above the acute toxicity for fresh water invertebrates and fish. The study shows that the Hula Valley was an important source of pesticides and TPs at the Upper Jordan River basin and that substance flushing is extremely important for pesticides‐monitoring campaigns.     

A model study of the summer Southeast Vietnam Offshore Current in the southern South China Sea

The western boundary current in the southern South China Sea (SCS) in summer does not always flow northward along the Indo-China Peninsula, it leaves the southeast coast of peninsula around 10–14°N, forming a strong eastward jet called “Vietnam Coastal Current” or “Southeast Vietnam Offshore Current” (SVOC). It is known that the wind stress curl is the major driving factor responsible for this current. In this paper, we carry on the study of the separation position, strength and forming time of this current. A connected single-layer/two-layer model is employed here to study these problems. According to the numerical experiments and analyses of the vorticity dynamics, it is found that, the local wind stress curl (including the northern cyclonic and the southern anticyclonic wind forcing curl), the nonlinear term, the topographic effect, the planetary vorticity advection and the water exchange between the SCS and Java Sea via the Sunda Shelf have an important effect on both the position where this current leaves the coast and its strength; when there is an inflow via the Sunda Shelf, the current is stronger and the separation position is more northward; whereas the water stratification, the coastline and the inflow of Kuroshio have little effect on its separation. In fact, two opposite flowing currents, the northward SVOC and the southward western branch of the cyclonic eddy to its north near the Indo-China Peninsula, collide with each other, and the strength of these two currents determine the separation position of the SVOC. Origin of the SVOC may be driven by the local negative wind stress curl in the middle SCS in mid-spring, this current flows along the coast of the Indo-China Peninsula and leaves the coast at high latitude, flowing northeastward; once the local positive wind stress curl near the northern Indo-China Peninsula or the negative one near the southern Indo-China Peninsula is large enough, this current will begin to leave the coast at low latitude.     

Trace metals in the North Sea

The distribution of zinc, manganese, nickel, copper and cadmium in water and biological material has been measured in the southern North Sea and Straits of Dover, and off the north-east coast of England. These investigations provide baseline values against which future pollution changes can be measured.     

The influence of cyanobacteria on oil polluted intertidal soils at the Saudi Arabian Gulf shores

In 1991 the second Gulf War lead to the largest oil spill in human history. Over 770 km of coastline from southern Kuwait to Abu Ali Island (Saudi Arabia) were smothered with oil and tar, erasing most of the local plant and animal communities. In the following year cyanobacteria colonized most of the oil polluted shores. In the study area at the Saudi Arabian Gulf coast north of Jubail three different processes were observed that followed the extensive formation of cyanobacterial mats. The first one is desiccation, cracking, and peeling of the cyanobacterial mats, thereby removing the uppermost part of the oiled sediment. The second is the resettlement of burrowing macrofauna like crabs and benthic animals such as gastropods, which outcompete the cyanobacteria again. The third process is further extensive growth of cyanobacteria building thick laminated mats. These layers, completely seal the surface and hence produce an anaerobic milieu which inhibits oil degradation. As long as such cyanobacteria exist, they will prevent microbial oil degradation as well as any resettlement by macrofauna.     

Evaluating Tsunami Impact on the Gulf of Cadiz Coast (Northeast Atlantic)

The Gulf of Cadiz coasts are exposed to tsunamis. Emergency planning tools are now taking into account this fact, especially because a series of historical occurrences were strikingly significant, having left strong evidence behind, in the mareographic records, the geological evidence or simply the memory of the populations. The study area is a strip along the Algarve coast, south Portugal, an area known to have been heavily impacted by the 1 November 1755 event. In this study we use two different tsunami scenarios generated by the rupture of two thrust faults identified in the area, corresponding to 8.1?C8.3 magnitude earthquakes. Tsunami propagation and inundation computation is performed using a non-linear shallow water code with bottom friction. Numerical modeling results are presented in terms of flow depth and current velocity with maximum values of 7?m and 8?m/s for inundation depth and flow speed, respectively. These results constitute a valuable tool for local authorities, emergency and decision planners to define the priority zones where tsunami mitigation measures must be implemented and to develop tsunami-resilient communities.