In this study, we investigated the influence of low level contamination by copper, lead and zinc on the functioning of estuarine sandflat ecosystems by comparing the strength and variability of relationships between benthic macrofauna and fluxes (oxygen and nutrients) at three clean and three mildly contaminated sites. Specifically, as indicators of ecosystem functioning, we examined relationships between bivalve biomass, total benthic respiration and ammonium release, and ammonium uptake and benthic primary production. Furthermore, a small amount of organic matter was added to experimental plots at all sites (35g/0.2m²) to evaluate stress-on-stress responses relative to controls. Relationships were strongest at the clean sites (steepest slopes, highest r² values, lowest p-values) and weakest at the mildly contaminated sites and in organically enriched plots. Our results suggest that changes in ecosystem functioning may be occurring at mild (<ERL) levels of pollution that are unlikely to cause widespread mortality of macrofauna.

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.

In recent years, there has been increasing interest in the significance of natural radionuclides, particularly ²¹⁰Po, in the marine environment. ²¹⁰Po, a naturally occurring alpha emitter, accumulates in marine organisms and reflects differences in their diets. In the literature, there is no data for ²¹⁰Po and ²¹⁰Pb activity concentrations for fish species on the Turkish coast of Aegean Sea. Therefore, in this study, multiple fish species were collected from six stations seasonally on the Turkish coast of Aegean Sea and were analyzed for their ²¹⁰Po and ²¹⁰Pb content. The ²¹⁰Po and ²¹⁰Pb concentrations in the fish samples were found to vary from undetectable levels to 499±44Bqkg⁻¹ dry weight (dw) and from 1.0±0.3Bqkg⁻¹ to 35±4.0Bqkg⁻¹ (dw), respectively. There were no significant differences in the activity concentrations of ²¹⁰Po and ²¹⁰Pb in fish samples between seasons (ANOVA, P>0.05). The highest dose contribution of ²¹⁰Po to humans was calculated to be 10,530μSvyear⁻¹.

In the study, we establish centennial records of anthropogenic lead pollution at different locations in the North Atlantic (Iceland, USA, and Europe) by means of lead deposited in shells of the long-lived bivalve Arctica islandica. Due to local oceanographic and geological conditions we conclude that the lead concentrations in the Icelandic shell reflect natural influxes of lead into Icelandic waters. In comparison, the lead profile of the US shell is clearly driven by anthropogenic lead emissions transported from the continent to the ocean by westerly surface winds. Lead concentrations in the European North Sea shell, in contrast, are dominantly driven by local lead sources resulting in a much less conspicuous 1970s gasoline lead peak. In conclusion, the lead profiles of the three shells are driven by different influxes of lead, and yet, all support the applicability of Pb/Ca analyses of A. islandica shells to reconstruct location specific anthropogenic lead pollution.

Concentrations of copper in water rose rapidly following the introduction of boats to a new marina in San Diego Bay. Two months after the marina reached half its capacity, a majority of water samples exceeded chronic and acute criteria for dissolved copper, and copper concentrations in several samples exceeded the highest concentrations observed in another marina that has been listed as an impaired water body. A box model suggested that a small fraction of the leached copper was sequestered in sediment. Copper concentrations in water entering the marina from the bay was more than half the chronic concentration limit, so only 50% of marina boat capacity could be accommodated without exceeding the chronic criterion more than 50% of the time. Copper concentrations in water may increase rapidly following boat introduction in small marinas, but could return to pre-introduction levels by controlling boat numbers or reducing use of copper-based paints.

Particulate metal concentrations were assessed before, during and after a flood episode in the Tagus estuary. Particulate metal concentrations showed a decrease during the flood period and very similar values in the months before and after the flood event. Before this period, sampling station characteristics were verified to be homogenous during the peak of the flooding event, as all of the sampling stations assumed very specific characteristics. One of the main consequences from the flood, concurrent with a decrease in particulate metal concentrations, was the high input of SPM into the estuarine area. This finding indicates higher levels of heavy metals in fine-sized particles at low SPM concentration than those present in coarser particles at high SPM levels. These periodic flood events can be considered as estuarine contamination masks and should be interpreted as periods of dilution in heavy metal contamination rather than as an estuarine cleansing process.

Aliağa Bay is one of the most important maritime zones of Turkey where shipping activity, shipbreaking industry, steel works and petrochemical complexes exist together. Concentrations of heavy metals and organic carbon in sediment of the Aliağa Bay were investigated to evaluate an environmental risk assessment from metals contamination in 2009–2010. Comparison of the metal concentrations with average shale and Mediterranean background levels revealed that most of the samples from the Aliağa were polluted with Hg, Cd, Pb, Cr, Cu, Zn, Mn and Ni. It was found that Hg, Pb, Cu, Zn and Ni levels in Aliağa Bay exceeded the PEL values. Sediments, contaminated with Pb, Cr, Cu, Zn and Ni were considered as heavily polluted per the SQG.

We investigated the partial pressure of carbon dioxide (pCO₂) in Jiaozhou Bay (JZB), which is surrounded by the economically developed city of Qingdao, during two cruises undertaken in November, 2007 (autumn) and February, 2008 (winter). Results indicated that sea surface pCO₂ in autumn varied between 315 and 720μatm, with an average level of 418μatm. In winter the sea surface pCO₂ ranged from 145 to 315μatm with an average of 249μatm, which is below atmospheric pCO₂. Despite seasonal temperature variation between autumn and winter, it was noted that biological process (production and respiration) were responsible for both spatial and seasonal variation during these seasons. We found that Jiaozhou Bay served as a net atmospheric CO₂ source in autumn (November) (2.87mmolm⁻²d⁻¹), while in winter (February) it served as a net sink (−16.22mmolm⁻²d⁻¹).

A CYP4 cDNA was cloned and characterized to identify the relationship between persistent organic pollutants and stress response in marine polychaete Perinereis aibuhitensis. The full length of PaCYP4 cDNA is 1857bp and encodes 481 amino acids. The deduced amino acid sequence showed 73% identity with CYP4BB1 from polychaete Nereis virens and shared high homology to other known CYP4 sequences. The expression level of PaCYP4 under petroleum hydrocarbon (PH) and deltamethrin (DM) exposure was detected using Real-time PCR. PH and combined toxicity treatments elevated the mRNA level of PaCYP4 in a dose- and time-dependent manner. The mRNA transcripts of PaCYP4 increased at the beginning of DM exposure and then eventually decreased, and the expression level of PaCYP4 down-regulated with increasing concentration of DM. CYP4 in P. aibuhitensis plays an important role in the metabolism of petroleum hydrocarbon and organochlorine pesticide.

In this study, the state of the five stations’ quality was assessed on the basis of determination of temporal and spatial variability of nutrients with physicochemical variables. Besides this, organic matter of sediment, secchi disc depth and suspended solids were also determined. The samples were collected seasonally from different areas such as harbor and important touristic marinas along the eastern Aegean during June 2008–2009. As a result, the nutrients ranged between NH₄: 0.10–25.6, NO₂: 0.01–1.5, NO₃: 0.19–7.0, o.PO₄: 0.17–6.8, TPO₄: 0.32–9.6 and Si: 0.30–13.8μM, respectively. Precipitation leads to large changes in temperature, salinity, dissolved oxygen and nutrients. The highest nutrient values in this study were observed during the rainy season except o.PO₄-P and TPO₄-P. However, the physico-chemical variables have exhibited considerable temporal variations while nutrients showed spatial differences. The relatively high nutrient increase in the sampling stations coupled with surface runoff events during rainy period and pollution arising from both point and non-point sources.