Baseline Hg concentration in bycatch fish from the SE Gulf of California were determined in muscle and liver of 19 species. Levels of Hg in muscle were compared with legal limits of this element in national and international legislation. Considering all fish species, mean concentrations in liver (2.458±1.997μgg⁻¹) were significantly higher (p<0.05) than in muscle (0.993±0.670μgg⁻¹). The sequence of averaged Hg concentrations in most ichthyofauna was liver>muscle. Highest level of Hg in muscle (2.556μgg⁻¹) and liver (7.515μgg⁻¹) corresponded to Diapterus peruvianus and Ophioscion strabo, respectively. Considering muscle samples, none of the species had levels of Hg above the limit (1.0μgg⁻¹ wet weight) in the Mexican legislation; with respect to the Japanese (0.4μgg⁻¹ wet weight) and British (0.3μgg⁻¹ wet weight) legislations, 26.3% and 31.6% of the species respectively, were above the corresponding limits.

The development of oil sorbents with high sorption capacity, low cost, scalable fabrication, and high selectivity is of great significance for water environmental protection, especially for oil spillage on seawater. In this work, we report nanoporous polystyrene (PS) fibers prepared via a one-step electrospinning process used as oil sorbents for oil spill cleanup. The oleophilic–hydrophobic PS oil sorbent with highly porous structures shows a motor oil sorption capacity of 113.87g/g, approximately 3–4times that of natural sorbents and nonwoven polypropylene fibrous mats. Additionally, the sorbents also exhibit a relatively high sorption capacity for edible oils, such as bean oil (111.80g/g) and sunflower seed oil (96.89g/g). The oil sorption mechanism of the PS sorbent and the sorption kinetics were investigated. Our nanoporous material has great potential for use in wastewater treatment, oil accident remediation and environmental protection.

Suspended sediment concentration (SS) is an important indicator of marine environmental changes due to natural causes such as tides, tidal currents, and river discharges, as well as human activities such as construction in coastal regions. In the Saemangeum area on the west coast of Korea, construction of a huge tidal dyke for land reclamation has strongly influenced the coastal environment. This study used remotely sensed data to analyze the SS changes in coastal waters caused by the dyke construction. Landsat and MODIS satellite images were used for the spatial analysis of finer patterns and for the detailed temporal analysis, respectively. Forty Landsat scenes and 105 monthly composite MODIS images observed during 1985–2010 were employed, and four field campaigns (from 2005 to 2006) were performed to verify the image-derived SS. The results of the satellite data analyses showed that the seawater was clear before the dyke construction, with SS values lower than 20g/m³. These values increased continuously as the dyke construction progressed. The maximum SS values appeared just before completion of the fourth dyke. Values decreased to below 5g/m³ after dyke construction. These changes indicated tidal current modification. Some eddies and plumes were observed in the images generated from Landsat data. Landsat and MODIS can reveal that coastal water turbidity was greatly reduced after completion of the construction.

Solar ultraviolet radiation (UVR, 280–400nm) is known to inhibit the photosynthesis of macroalgae, whereas nitrogen availability may alter the sensitivity of the algae to UVR. Here, we show that UV-B (280–315nm) significantly reduced the net photosynthetic rate of Gracilaria lemaneiformis. This inhibition was alleviated by enrichment with ammonia, which also caused a decrease in dark respiration. The presence of both UV-A (315–400nm) and UV-B stimulated the accumulation of UV-absorbing compounds. However, this stimulation was not affected by enrichment with ammonia. The content of phycoerythrin (PE) was increased by the enrichment of ammonia only in the absence of UVR. Ammonia uptake and the activity of nitrate reductase were repressed by UVR. However, exposure to UVR had an insignificant effect on the rate of nitrate uptake. In conclusion, increased PE content associated with ammonia enrichment played a protective role against UVR in this alga, and UVR differentially affected the uptake of nitrate and ammonia.

In order to explore the detoxification mechanisms adopted by mangrove under cadmium (Cd) stress, we investigated the subcellular distribution and chemical forms of Cd, in addition to the change of the thiol pools in Kandelia obovata (S., L.) Yong, which were cultivated in sandy culture medium treated with sequential Cd solution. We found that Cd addition caused a proportional increase of Cd in the organs of K. obovata. The investigation of subcellular distribution verified that most of the Cd was localized in the cell wall, and the lowest was in the membrane. Results showed sodium chloride and acetic acid extractable Cd fractions were dominant. The contents of non-protein thiol compounds, Glutathione and phytochelatins in K. obovata were enhanced by the increasing strength of Cd treatment. Therefore, K. obovata can be defined as Cd tolerant plant, which base on cell wall compartmentalization, as well as protein and organic acids combination.

In view of increasing environmental awareness and biodiversity conservation, understanding the main forcing mechanism driving biogeochemical cycles in coral reefs and lagoon coastal areas is a priority. La Niña events cause unbalanced situations in the Equatorial Pacific and result in enhanced precipitation in South West Pacific coastal areas. We investigated the impact of heavy rainfalls during the 2008 La Niña event on the New Caledonia lagoon using a 3D coupled on-line hydrodynamic–biogeochemical model. Simulations and data showed that the whole lagoon was impacted by river inputs and stronger hydrodynamics, enhancing chlorophyll-a concentration by a factor between 1.7 and 1.9. The coupled model provided new insights into plume transport, highlighting that eastern plumes can be advected northwards or can reach the South West Lagoon, depending on the balance between regional, tide-induced, and wind-induced surface currents. It also provided a synoptic view of lagoon biogeochemical–hydrodynamic response, when remote sensing data are not available due to cloud coverage.

Feathers are useful to determine mercury (Hg) contamination. We evaluated the mercury concentration in feathers of Magellanic penguins (Spheniscus magellanicus) age 1.5years to 25years at Punta Tombo, Argentina before and during their molt. Mercury ranged between <1.4 and 367ng/gdryweight, with three extreme high values (8996ng/g, 3011ng/g and 1340ng/g) all in young adults. The median concentration was lowest for juveniles and significantly higher for adults but with high variation among older adults. Males and females had similar mercury loads. Compared with other penguin species, concentrations in Magellanic penguins were low. Mercury levels for Magellanic penguins in the Southwest Atlantic for older adults averaged 206±98ng/g, and serve as a baseline for biomonitoring and/or ecotoxicological studies.

Vertical profiles of dissolved and particulate Mn, Fe, Ni, Cu, Zn, Cd, Pb, and ²³⁴Th were determined in the Hung-Tsai Trough off southwestern Taiwan during 19–23 November, 2004. Except in the case of Cd, the distribution coefficient (Kd) of the trace elements showed a negative correlation with the suspended particle concentration. Based on the average Kd values, the general sequence of particle affinities for the eight trace elements is, from highest to lowest, Fe>Mn≈Pb>Zn≈Th>Cd≈Cu≈Ni. The trace metal data was coupled with the particle removal flux estimated from ²³⁴Th/²³⁸U disequilibrium to investigate metal removal by particle sinking from the euphotic layer. The residence time of trace elements with respect to particle removal from the euphotic layer was estimated. A negative correlation between the residence time and the distribution coefficient for the trace metals was found.

In Stone Town, Zanzibar, sewage treatment is minimal, with a biological oxygen demand reduction to 60% and no removal of bacteria or nutrients. Here, Stone Town’s sewage pollution was studied by measuring Enterococci and NH₄ ⁺ concentrations in seawater and δ¹⁵N of benthic organisms; samples were collected along the Stone Town shoreline and from offshore coral reefs. Public perceptions of sewage pollution were investigated via interviews. Enterococci from the Stone Town shoreline exceeded USEPA guidelines for recreational use. Benthic organisms from two of the four reefs were relatively enriched (δ¹⁵N>10‰), indicative of sewage derived N. δ¹⁵N values of organisms from Stone Town exceeded 16‰. A strong correlation was found between Enterococci and δ¹⁵N across sites, while step-wise regression indicated rainfall and tidal stage as important predictors for bacterial concentrations. These data provide an important impact assessment from which the efficacy of future policy and management change can be assessed.

Rare earth elements (REE) were analyzed in surface sediments from the Guadiana Estuary (SW Iberian Pyrite Belt). NASC (North American Shale Composite) normalized REE patterns show clearly convex curvatures in middle-REE (MREE) with respect to light- and heavy-REE, indicating acid-mixing processes between fluvial waters affected by acid mine drainage (AMD) and seawater. However, REE distributions in the mouth (closer to the coastal area) show slightly LREE-enriched and flat patterns, indicating saline-mixing processes typical of the coastal zone. NASC-normalized ratios (La/Gd and La/Yb) do not discriminate between both mixing processes in the estuary. Instead, a new parameter (EMREE) has been applied to measure the curvature in the MREE segment. The values of EMREE>0 are indicative of acid signatures and their spatial distribution reveal the existence of two decantation zones from flocculation processes related to drought periods and flood events. Studying REE fractionation through the EMREE may serve as a good proxy for AMD-pollution in estuarine environments in relation to the traditional methods.