Ballast water exchange processes facilitate the dispersal and unnatural geographic expansion of phytoplankton, including harmful algal bloom species. From 2005 to 2010, over 45,000 vessels (∼8000 annually) travelled across Galveston Bay (Texas, USA) to the deep-water ports of Houston (10th largest in the world), Texas City and Galveston. These vessels (primarily tankers and bulkers) discharged ∼1.2×10⁸metrictons of ballast water; equivalent to ∼3.4% of the total volume of the Bay. Over half of the ballast water discharged had a coastwise origin, 96% being from US waters. Galveston Bay has fewer non-indigenous species but receives a higher volume of ballast water discharge, relative to the highly invaded Chesapeake and San Francisco Bays. Given the magnitude of shipping traffic, the role of Galveston Bay, both as a recipient and donor region of non-indigenous phytoplankton species is discussed here in terms of the invasibility risk to this system by way of ballast water.

Aliağa Bay is one of the most important maritime zones of Turkey where shipping activity, shipbreaking industry, steel works and petrochemical complexes exist together. Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons in sediment of the Aliağa Bay were investigated to evaluate an environmental risk assessment from PAHs contamination in 2009–2010. Aliphatic and PAHs diagnostic ratios were showed to be mainly petroleum-originated and pyrolitic contaminations, respectively. The TEL/PEL analysis suggests that Aliağa sediments were likely to be contaminated by acutely toxic PAH compounds.

The heavy metal inventory and the ecological risk of the estuarine sediments in Hailing Bay, an important maricultural zone along the southern coast of China, were investigated. Results show that the surface sediments were mainly polluted by As (2.17–20.34mg/kg), Ni (1.37–42.50mg/kg), Cu (1.21–58.84mg/kg) and Zn (11.69–219.22mg/kg). Furthermore, the aquafarming zone was significantly more polluted than the non-aquafarming zone, and cluster analysis suggested additional sources of heavy metal input in the aquafarming zone. As, Cr, Cu, Ni, Pb and Zn were mainly present in the non-bioavailable residual form in the surface sediments, whereas Cd was predominantly in the highly mobile acid soluble and reducible fractions. The ecological risk of the polluted sediments stemmed mainly from Cd, and from As, Cu and Pb to less degrees. The highest potential risks occurred near the aquaculture base, indicating the need to control heavy metal inputs from aquafarming activities.

We have studied the distribution and value of phenolic endocrine disrupting chemicals (EDCs) in surface sediment samples taken from Anzali Wetland, Iran. These samples were collected from 22 stations during the time span of June–May 2010. In each of the sampling stations, we detected 4-nonylphenol (4-NP), octylphenol (OP), and bisphenol A (BPA) with maximal concentrations of 29, 4.3, and 7μgg⁻¹ dry weight (dw), respectively. High levels of alkylphenols (APs) and BPA were also found near urban areas. Furthermore there were no significant differences between those stations in terms of the detected levels. One of the important factors in controlling the fate of these compounds in the aquatic environment appeared to be Total Organic Carbon (TOC). Hierarchical cluster analysis showed differences in the biomarker characteristics of EDCs and TOC between the stations. Our findings indicate that EDCs are ubiquitous in sediments from northeast Wetlands of Iran, contaminating the aquatic habitats in this area.

Microcosms experiments were carried out to evaluate the effect of bioemulsificant exopolysaccharide (EPS₂₀₀₃) on microbial community dynamics. An experimental seawater microcosm, supplemented with crude oil and EPS₂₀₀₃ (SW+OIL+EPS₂₀₀₃), was monitored for 15days and compared to control microcosm (only oil-polluted seawater, SW+OIL). Determination of bacterial abundance, heterotrophic cultivable and hydrocarbon-degrading bacteria were carried out during all experimentation period. The microbial community dynamic was monitored by isolation of total RNA, RT-PCR amplification of 16S rRNA, cloning and sequencing. Oil degradation was monitored by GC–MS analysis. Bioemulsificant addition stimulated an increase of the total bacterial abundance, change in the community structure and activity. The bioemulsificant also increased of 5 times the oil biodegradation rate. The data obtained from microcosm experiment indicated that EPS₂₀₀₃ could be used for the dispersion of oil slicks and could stimulate the selection of marine hydrocarbon degraders thus increasing bioremediation process.

Trace element levels in fish are of particular interest, owing the potential risk to human health. In accordance, juveniles of Dicentrarchus labrax and of Liza aurata were sampled and arsenic, cadmium, chromium, selenium and zinc were determined in the muscle. The levels of trace elements in muscle demonstrated to be similar for both species and sites, with the exception of selenium levels at reference, which seemed to be higher in D. labrax. Moreover, apart from arsenic levels in muscle, all elements were in conformity with the existent regulatory guidelines for fish consumption. The dietary intake of each element was also calculated, with arsenic and selenium showing intakes above the recommended dietary allowances. Nevertheless, no arsenic speciation was carried out and thus no accurate risk evaluation could be established. Additionally, selenium levels never exceeded the dietary allowances more than five times, which are considered safe.

We investigated heavy metal concentrations of zinc (Zn), copper (Cu), chromium (Cr), and lead (Pb), their spatial distribution and enrichment factor index in surface sediments of the Gorgan Bay. Sediment Quality Guidelines were also applied to assess adverse biological effects of these metals. Heavy metals were determined by inductively coupled plasma-mass spectroscopy (ICP-MS). The results indicated mean concentrations (ppm) of heavy metals were (mean±S.D.) Pb: 11.5±4.88, Cu: 18±8.83, Zn: 42±22.15 and Cr: 32±15.19. Based on Enrichment index, the Gorgan Bay is a low-enriched to non-enriched bay. Heavy metal contents were lower than the standard limits of PEL, ERL, and ERM that reveal no threatening influence of the metals in the Bay.

In this paper, we described the applications of two-photon laser confocal scanning microscopy (TPLCSM) for in situ monitoring and visualizing the localizations and movements of naphthalene, phenanthrene, and pyrene into living Aegiceras corniculata (L.) Blanco seedlings (A. corniculata). Experimental results demonstrated that all of the polycyclic aromatic hydrocarbons (PAHs) were observed entering into the root of A. corniculata and being transmitted to the stem. The transport processes and subsequent storages of the three typical PAHs into A. corniculata were similar. Further studies indicated that the transmission rates of the PAHs in A. corniculata were in the order of naphthalene>phenanthrene>pyrene. Compared with the control group, the growth of the A. corniculata was inhibited by these three specific PAHs, and the inbibitional effect of naphthalene was the most obvious (P<0.05). Furthermore, without the need for sample manipulation or modification this TPLCSM provides us a real-time tool for direct observation of organic chemicals within plants.

Within the context of risk evaluation of chemical spillages into the marine environment, this paper reports on an offshore experiment to study the behaviour of styrene spilled into sea under natural conditions and discusses theoretical approaches. Floating structures were used to enclose the spillage and the gaseous cloud formation, and dissolution processes were in situ monitored. The identification of spill risks for man and marine environment through GESAMP’s hazard profile is described for styrene: Styrene is rated as a chemical with a significant health hazard that will float but also evaporate. However, monitoring of the water column in the experiments showed that the concentration of styrene in water during the first hour represents 50% of the product spilled. For the potentially exposed public, the GESAMP hazard rating recommends the closure of beaches and evacuation. The risk assessment developed from experimental data confirms this safety advice.

The impacts of ocean acidification on coastal biofilms are poorly understood. Carbon dioxide vent areas provide an opportunity to make predictions about the impacts of ocean acidification. We compared biofilms that colonised glass slides in areas exposed to ambient and elevated levels of pCO₂ along a coastal pH gradient, with biofilms grown at ambient and reduced light levels. Biofilm production was highest under ambient light levels, but under both light regimes biofilm production was enhanced in seawater with high pCO₂. Uronic acids are a component of biofilms and increased significantly with high pCO₂. Bacteria and Eukarya denaturing gradient gel electrophoresis profile analysis showed clear differences in the structures of ambient and reduced light biofilm communities, and biofilms grown at high pCO₂ compared with ambient conditions. This study characterises biofilm response to natural seabed CO₂ seeps and provides a baseline understanding of how coastal ecosystems may respond to increased pCO₂ levels.