Evaluation of atmospheric transport as a nonpoint source of polycyclic aromatic hydrocarbons in marine sediments of the Eastern Mediterranean

Coastal marine sediment, air and seawater samples were collected at six sampling stations in the Eastern Mediterranean Sea distant from pollutant point sources. All sediment samples were analyzed to determine polycyclic aromatic hydrocarbon (PAH), black carbon (BC) and organic carbon (OC) contents. The PAH contents of gaseous and seawater samples of the study were determined in order to evaluate the role of air–sea exchange as PAH nonpoint source to the marine sediments. The average concentration of the total PAHs (∑PAHs) in the sediments varied from 2.2 to 1056.2 ng g⁻¹ dry weight. The average BC and OC contents varied from 0.3 to 5.6 and from 2.9 to 21.4 mg g⁻¹ dry weight, respectively. ∑PAH concentration in the marine atmosphere varied from 20.0 to 83.2 ng m⁻³. Air–water exchange flux (F_A–W) estimation has indicated air transport as a significant source of PAHs to pristine marine sediments of Eastern Mediterranean. In addition, the significant correlation between the PAHs and the organic and soot carbon content further suggests the importance of atmospheric input of PAHs to the sediments.     

Assessment of Aliphatic and Polycyclic Aromatic Hydrocarbons and Trace Elements in Coastal Sediments of the Saronikos Gulf,Greece (Eastern Mediterranean)

Surface sediments from the Saronikos Gulf were analyzed for their aliphatic hydrocarbon (AHC) and polycyclic aromatic hydrocarbon (PAH) content by gas chromatography – mass spectrometry (GC/MS). The concentrations of Fe, Cr, As, Sb, Co and Sc were also determined by neutron activation analysis (NAA). The survey was performed at the beginning of the operation of Athens’ sewage primary treatment unit and the results can be used to monitor the unit's long-term effects in the area. The composition of aliphatic hydrocarbons indicated a chronic oil-pollution in the Saronikos Gulf sediments. The industrially impacted Elefsis Bay sediments suffered from heavy petroleum pollution, while the sediments near the sewage outfall had a moderate degree of pollution. Mixed source patterns of polycyclic aromatic hydrocarbons with dominant pyrolytic inputs have been identified in the sediments. Total concentrations of Fe, As and Sb along with their Sc normalized values presented elevated values in Elefsis Bay sediments. Chromium was found enriched in the sediments near the Athens sewage outfall. Factor analysis results showed that a part of As and Sb in Elefsis Bay sediments could be associated with organic or sulphidic phases. In addition, the lithogenic fraction of the sediments and the Fe oxides/hydroxides were important trace element carriers. Chromium and PAH inputs from the sewage outfall were also detected. Comparison of PAH and trace element concentrations with internationally-used sediment quality guidelines (SQG) revealed that Elefsis Bay sediments had the greatest potential of causing adverse effects in benthic organisms.     

Mud volcanoes and gas hydrates in the Anaximander mountains (Eastern Mediterranean Sea)

Detailed multibeam, sedimentological, and geophysical surveys provide ample new data to confirm that the Anaximander Mountains (Eastern Mediterranean) are an important area for active mud volcanism and gas hydrate formation. More than 3000 km of multibeam track length was acquired during two recent missions and 80 gravity and box cores were recovered. Morphology and backscatter data of the study area have better resolution than previous surveys, and very detailed morphology maps have been made of the known targeted mud volcanoes (Amsterdam, Kazan and Kula), especially the Amsterdam “crater” and the related mud breccia flows. Gas hydrates collected repeatedly from a large area of Amsterdam mud volcano at a sub-bottom depth of around 0.3–1.5 m resemble compacted snow and have a rather flaky form. New gas hydrate sites were found at Amsterdam mud volcano, including the mud flow sloping off to the south. Gas hydrates sampled for the first time at Kazan mud volcano are dispersed throughout the core samples deeper than 0.3 m and display a ‘rice’-like appearance. Relative chronology and AMS dating of interbedded pelagic sediments (Late Holocene hemipelagic, sapropel layer S1 and ash layers) within the mud flows indicate that successive eruptions of Kula mud volcano have a periodicity of about 5–10 kyrs. New mud volcanoes identified on the basis of multibeam backscatter intensity were sampled, documented as active and named “Athina” and “Thessaloniki”. Gas hydrates were sampled also in Thessaloniki mud volcano, the shallowest (1264 m) among all the active Mediterranean sites, at the boundary of the gas hydrate stability zone. Biostratigraphical analyses of mud breccia clasts indicated that the source of the subsurface sedimentary sequences consists of Late Cretaceous limestones, Paleocene siliciclastic rocks, Eocene biogenic limestones and Miocene mudstones. Rough estimations of the total capacity of the Anaximander mud volcanoes in methane gas are 2.56–6.40 km³.     

渤海石油污染:来自表层沉积物中生物标志物的证据

通过对渤海表层沉积物中饱和烃的分布、来源和分子组成特征的系统分析,探讨了沉积物中生物标志物对石油污染的指示意义。研究表明,沉积物中色谱不可分辨的混合物(UCM)和正构烷烃的分布及组成特征显示出沉积物不同程度地受到了石油烃输入和细菌微生物作用的影响,其中以渤海湾沿岸区域最为明显。渤海湾近岸区和黄河口附近沉积物中正构烷烃平均碳链长度(ACL)低于其他地区,姥鲛烷/植烷(Pr/Ph)也普遍低于1.0,表明可能受到来自于石油平台开采活动、船舶航行、河流输入的石油烃的影响。C₂₇-18α(H)-三降藿烷(Ts)与C₂₇-17α(H)-三降藿烷(Tm)的比值(Ts/Tm)、C₃₁升藿烷22S/(22S+22R)和αααC₂₉甾烷20S/(20S+20R)的比值表明该区域沉积物中有机质成熟度较高,可能受到外来石油烃输入及其衍生物的影响。通过与周边环境中生物标志物分子组成特征的对比发现,沉积物中甾烷和萜类化合物主要来源于石油及其衍生物。将饱和烃各参数进行归一化处理,得到了石油污染的综合替代性指标,并初步圈定了石油污染相对较重的区域。     

南海东部表层沉积物中轻矿物分布与来源

对南海东部 158个表层沉积物样品的分析结果表明,轻矿物来源多样,生物成因矿物含量高.除去生物骨屑后,沉积物中白云母等碎屑轻矿物的分布规律显示,华南大陆是南海东部陆源碎屑物质的主要来源,其影响可达 17°N线以南.火山玻璃主要分布于 15°N线附近,其中褐色火山玻璃主要来源于本地海山物质,为火山玻璃的主体,而无色火山玻璃含量较低,它可能来自附近火山喷发物.     

Polycyclic aromatic hydrocarbons in surface sediments of the Zhelin Bay in the South China Sea

This study examined the concentrations of polycyclic aromatic hydrocarbons (PAHs) in surface sediments collected in July 2004 from eight stations in the Zhelin Bay, one of the most important bays for large-scale mariculture in Guangdong Province. Thirteen individual parent PAH compounds were identified using high performance liquid chromatography with UV detection. The overall average concentration of total PAHs was 477.0 ng/g, ranging from 146.1 to 928.8 ng/g. Low molecular mass PAHs with two to three rings (e.g., acenaphthene) were dominant in each sample. The PAH concentration varied among sampling stations, with the highest concentration observed at bay outlets and the lowest found at stations outside the bay. Ratios of low to high molecular mass PAHs and fluoranthene to pyrene were used to determine the origin of PAHs, and results indicated mainly petroleum-derived contamination. Compared with other bays and harbors around the world, the total concentrations of PAHs in surface sediments at the Zhelin Bay are moderate, but this does not exclude the possibility of potential impact on human consumers because some strong carcinogenic PAHs with high molecular mass were found at the station with a nearby caged-fish and oyster farm. Long-term monitoring of PAH contamination in the Zhelin Bay is recommended to reduce the potential toxicological effects on aquatic organisms and humans.     

Vertical Distribution of Meiobenthos in Bathyal Sediments of the Eastern Mediterranean Sea: Relationship with Labile Organic Matter and Bacterial Biomasses

Abstract. Quantitative information on the vertical distribution of meiofaunal abundances and biomass were obtained from samples collected at 3 bathyal stations in the Eastern Mediterranean Sea located at the same depth but characterized by different food supply. Vertical distribution patterns of nieiofauna were investigated in relation to the biochemical composition of the sediment organic matter (proteins, carbohydrates, and lipids) and compared to benthic bacterial standing stocks. No significant relationship between bacteria and meiofauna was found, whereas a significant relationship between protein and lipid concentrations and total meiofauna density was observed. These data suggest that labile organic matter. considered as material readily aVdihbk to benthic consumers, may be an important factor regulating meiofaunal abundance and vertical distribution in deep-sea sediments.     

Transient Eastern Mediterranean deep waters in response to the massive dense-water output of the Aegean Sea in the 1990s

We present a detailed account of the changing hydrography and the large-scale circulation of the deep waters of the Eastern Mediterranean (EMed) that resulted from the unique, high-volume influx of dense waters from the Aegean Sea during the 1990s, and of the changes within the Aegean that initiated the event, the so-called ‘Eastern Mediterranean Transient’ (EMT). The analysis uses repeated hydrographic and transient tracer surveys of the EMed in 1987, 1991, 1995, 1999, and 2001/2002, hydrographic time series in the southern Aegean and southern Adriatic Seas, and further scattered data. Aegean outflow averaged nearly 3 × 10⁶ m³ s⁻¹ between mid-1992 and late 1994, and was largest during 1993, when south and west of Crete Aegean-influenced deep waters extended upwards to 400 m depth. EMT-related Aegean outflow prior to 1992, confined to the region around Crete and to 1800 m depth-wise, amounted to about 3% of the total outflow. Outflow after 1994 up to 2001/2002, derived from the increasing inventory of the tracer CFC-12, contributed 20% to the total, of 2.8 × 10¹⁴ m³. Densities in the southern Aegean Sea deep waters rose by 0.2 kg/m³ between 1987 and 1993, and decreased more slowly thereafter. The Aegean waters delivered via the principal exit pathway in Kasos Strait, east of Crete, propagated westward along the Cretan slope, such that in 1995 the highest densities were observed in the Hellenic Trench west of Crete. Aegean-influenced waters also crossed the East Mediterranean Ridge south of Crete and from there expanded eastward into the southeastern Levantine Sea. Transfer into the Ionian mostly followed the Hellenic Trench, largely up to the trench’s northern end at about 37°N. From there the waters spread further west while mixing with the resident waters. Additional transfer occurred through the Herodotus Trough in the south. Levantine waters after 1994 consistently showed temperature–salinity (T–S) inversions in roughly 1000–1700 m depth, with amplitudes decreasing in time. The T–S distributions in the Ionian Sea were more diverse, one cause being added Aegean outflow of relatively lower density through the Antikithira Strait west of Crete. Spreading of the Aegean-influenced waters was quite swift, such that by early 1995 the entire EMed was affected. and strong mixing is indicated by near-linear T–S relationships observed in various places. Referenced to 2000 and 3000 dbar, the highest Aegean-generated densities observed during the event equaled those generated by Adriatic Sea outflow in the northern Ionian Sea prior to the EMT. A precarious balance between the two dense-water source areas is thus indicated. A feedback is proposed which helped triggering the change from a dominating Adriatic source to the Aegean source, but at the same time supported the previous long-year dominance of the Adriatic. The EMed deep waters will remain transient for decades to come.     

东海外陆架-陆坡-冲绳海槽不同沉积单元底质沉积物成因及物源分析

通过对东海外陆架-陆坡-冲绳海槽表层沉积物粒度和黏土矿物组成的分析, 探讨了3个不同沉积单元底质沉积物成因及物质来源。结果表明, 东海外陆架→陆坡→冲绳海槽, 沉积物粒度整体上逐渐变细。东海外陆架沉积物具有明显海滩砂或者破浪带砂的特征, 为晚更新世冰消期海侵的产物, 属于“残留沉积”。海槽西坡沉积物粒度参数具有重力流沉积特征, 反映了沉积物由外陆架向海槽以滑塌或重力流的搬运方式。海槽槽底细颗粒沉积物悬移组分占主导的特点体现了半深海沉积特征, 其主要来源于台湾和中国大陆长江、闽江等入海河流。物质来源一方面反映了黑潮对于细颗粒台湾源物质的输运的巨大作用; 另一方面体现了来源于中国大陆源细颗粒物质存在以近底侧向搬运、“冬贮夏输”悬浮搬运等多种输运机制。     

楚科奇海表层沉积物的生源组分及其对碳埋藏的指示意义

工业革命以来大气中CO₂浓度由280 ppm剧增至375 ppm,是导致全球气候变暖的主要原因[1]。海洋作为大气CO₂的“汇”之一,每年可吸收人类释放CO₂气体总量的30%,对全球碳循环的收支平衡有重要作用[2]。两极地区是CO₂的主要汇区,也是全球变化的重要反馈窗口。因此,了解碳在北冰洋的生物地球化学循环过程是十分必要的[3-4]。海洋中的生源沉积物主要来自于海洋上层浮游生物碎屑的沉降,主要由蛋白石(以生物硅代替,BSi)、碳酸钙(CaCO₃)和有机质(通常用有机碳替代,TOC)组成[5]。     

南大西洋洋中脊附近沉积物中烃类分布和组成研究

我们利用气相色谱-质谱联用仪(GC-MS)测试了南大西洋洋中脊附近采集的沉积物样品中烃类的分布和组成。通过分析发现,样品中烃类表现出明显的双峰分布,同时明显的富集3-甲基烷烃、8-甲基烷烃以及2,4,(n-1)-三甲基烷烃,这可能是海底微生物代谢作用的结果。样品中也富集萜烷、藿烷和甾烷等生物标志物,这也支持样品中烃类主要为微生物来源的观点。样品中沥青和烃类显示出距离热液区近的2V-TVG10和26V-TVG05站位含量高,而距离热液区远的22IV-TVG01、22V-TVG11和22V-TVG14站位含量低的趋势,暗示出样品中沥青以及烃类的分布和组成可能受到海底热液活动的影响。     

Distributions and sources of bulk organic matter and aliphatic hydrocarbons in surface sediments of the Bohai Sea, China

Surface sediment samples from a matrix of fifty-five sites covering virtually the entire Bohai Sea (Bohai), China were analyzed for total organic carbon (TOC), total nitrogen (TN), n-alkanes, unresolved complex mixture (UCM), biomarkers and stable carbon isotopic composition (δ¹³C), and principal component analysis was performed for source identification of organic matter (OM). The distribution of organic carbon correlated well with sediment grain size with the finest sediments having the highest concentration, suggesting the influence of hydrodynamics on the accumulation of sedimentary organic matter (SOM). The corrected TOC/ON (organic nitrogen) ratios and δ¹³C indicated mixed marine and terrestrial sources of SOM. Results suggested that δ¹³C could be used as a potential indicator to observe the dispersion of Huanghe-derived sediments in Bohai. Total n-alkane concentrations varied over 10-fold from 0.39 to 4.94 μg g^− 1 (dry weight) with the maximum terrigenous/aquatic alkane ratio observed at the Huanghe River Estuary (HRE) due to more higher plant OM from riverine inputs. C₁₂–C₂₂ n-alkanes with even-to-odd predominance were observed in several central-eastern Bohai sites. The HRE and its adjacent area is the main sink for the Huanghe river-derived OC. The ubiquitous presence of UCM, biomarkers (hopanes and steranes) and PCA results indicated the presence of petroleum contamination in Bohai, mainly from offshore oil exploration, discharge of pollutants from rivers, shipping activities and atmospheric deposition.     

Marine Protected Areas in the Mediterranean Sea: Objectives, Effectiveness and Monitoring

Abstract. The number of Marine Protected Areas (MPAs) is continuously increasing worldwide because of the increasing recognition of the profound effects that humans can have on marine systems. A large body of literature deals with marine reserves and their potential as conservation and management tools. In several cases, empirical evidence demonstrated that reserves can harbour greater diversity, higher abundance, and larger organisms than unprotected areas. In most cases, however, reserve design and site selection involved little scientific justification, with no direct test of most of the mechanisms assumed to work in a marine reserve. Field investigations of subtidal marine reserves are generally confounded by intrinsic ecological differences between sites investigated inside and outside reserves, by a lack of site and reserve replication, or by the absence of information about the biota before reserve establishment. This is particularly true in the Mediterranean Sea. The aim of this paper is to show that, at least in the Mediterranean basin, the effectiveness of MPAs has been rarely demonstrated because of lack of appropriate sampling designs. An MPA can be considered as a zone subjected to human impact, presumably a positive one. As a consequence, we propose the use of experimental procedures generally utilised for detecting environmental impacts.     

Ontogenetic shifts and temporal changes in the trophic patterns of the deep‐sea red shrimp,Aristaeomorpha foliacea (Decapods: Aristeidae), in the Eastern Ionian Sea (Eastern Mediterranean)

The purpose of this paper is to provide the first detailed data concerning the diet and feeding activity of the giant red shrimp, Aristaeomorpha foliacea, in the Eastern Ionian Sea (Eastern Mediterranean), in relation to season, size class and sex. Feeding activity in A. foliacea was intense, based on its low vacuity index and high prey diversity, with a diet dominated by mesopelagic prey and less frequent occurrence of benthic taxa. Giant red shrimp displayed a highly diversified diet that exhibited slight seasonal fluctuations. The diets of both sexes consisted of 60 different prey categories belonging chiefly to three groups: crustaceans (e.g. decapods, such as Plesionika spp. and Pasiphaeidae, amphipods), cephalopods (mainly Enoploteuthidae) and fishes (Myctophidae, Macrouridae). These three prey categories accounted for 72–82% of the relative abundance and total occurrence for males and 70–88% for females, respectively. Variation in food availability, as well as increased energy demands related to gonad development and breeding activity, appear to be critical factors driving temporal changes in feeding strategy. Feeding activity increased during spring and summer, which coincides with reproductive activities (mating, gonad maturation, egg‐laying). Females seem to be more active predators than males, consuming prey with greater swimming ability. However, ontogenetic shifts in diet were also apparent, despite high dietary overlap among small, medium and large females. Large individuals, which are more efficient predators, selected highly mobile prey (e.g. fishes), whereas small individuals consumed low‐mobility prey (e.g. copepods, ostracods, tanaids and sipunculans).     

白令海和楚科奇海表层沉积物中多环芳烃降解微生物多样性

为了研究白令海(海盆及陆架)至楚科奇海陆架表层沉积物中多环芳烃(PAHs)降解菌的多样性,并获得新的PAHs降解菌资源。在GC-MS分析沉积物中PAHs种类和含量的基础上,以萘、菲和芘的混合物为唯一碳源和能源对表层沉积物样品进行富集,通过平板分离鉴定可培养菌株,并验证其降解能力;同时利用变性梯度凝胶电泳(DGGE)和Illumina高通量测序技术分析降解菌群结构。GC-MS测定结果表明,14个表层沉积物中PAHs总干质量介于32.99~276.97ng/g。富集菌群中共分离获得51株可培养细菌,平板纯培养、PCR-DGGE及Illumina测序结果均表明,菌群中优势的降解菌是γ-proteobacteria的Marinobacter,Pseudoalteromonas,Pseudomonas和Actinobacteria门的Dietzia菌。此外,Illumina测序结果还表明14个降解菌群在菌群结构组成上,可分为海盆区和陆架区两种类群;同时检测到一些低丰度的海洋专属PAHs降解菌,如Cycloclasticus,Alteromonas和Neptunomonas等。本文结果将加深对白令海及楚科奇海表层沉积物中PAHs降解菌资源与生物多样性的认识。     

Characterization of bacterial symbioses in Myrtea sp. (Bivalvia: Lucinidae) and Thyasira sp. (Bivalvia: Thyasiridae) from a cold seep in the Eastern Mediterranean

Cold seeps have recently been discovered in the Nile deep‐sea fan (Eastern Mediterranean), and data regarding associated fauna are still scarce. In this study, two bivalve species associated with carbonate crusts and reduced sediment are identified based on sequence analysis of their 18S and 28S rRNA‐encoding genes, and associated bacterial symbioses are investigated using 16S rRNA gene sequencing and microscopy‐based approaches. The specimens are closely related to Myrtea spinifera and Thyasira flexuosa, two species previously documented at various depths from other regions but not yet reported from the Eastern Mediterranean. Both species harbour abundant gammaproteobacterial endosymbionts in specialized gill epithelial cells. The Myrtea‐associated bacterium is closely related to lucinid symbionts from both deep‐sea and coastal species, whereas the Thyasira‐associated bacterium is closely related to the symbiont of a T. flexuosa from coastal waters off the U.K. An epsilonproteobacterial sequence has also been identified in Thyasira which could correspond to a helicoid‐shaped morphotype observed by electron microscopy, but this was not confirmed using fluorescent in situ hybridization. Virus‐like particles were observed within some symbionts in Thyasira, mostly in bacteriocytes localized close to the ciliated zone of the gill filament. Overall, results indicate that very close relatives of shallow species M. spinifera and T. flexuosa occur at cold seeps in the Eastern Mediterranean and harbour chemoautotrophic symbioses similar to those found in their coastal relatives.     

南海表层沉积物火山玻璃分布特征与源区分析

火山碎屑是边缘海沉积的重要来源,其分布特征对研究沉积作用与构造活动具有重要意义。对南海2276个表层站位碎屑矿物分析表明,664个站位含火山玻璃,占总站位数的29.17%,其中含量最高达95.8×10−3。表层沉积物火山玻璃主要出现在南海东部海域,往西呈逐渐降低趋势。南海东部主要重矿物磁铁矿和角闪石分布与火山玻璃十分相似,表明可能具有相同的来源。这些特征表明火山玻璃主要来自菲律宾群岛。这与南海东缘的琉球-台湾-菲律宾火山－地震带的吕宋岛大量活火山分布吻合。南海南缘苏门答腊-爪哇岛弧火山-地震带,虽然第四纪火山和地震活动频发,但对表层样火山玻璃贡献不大。南海海域火山可能有少量贡献,但不是主要因素,南海北缘及西缘基本没有贡献火山玻璃。     

黄海、东海陆架区沉积物中氮的形态分布及与浮游植物总量的关系

利用分级浸取分离法将黄海、东海陆架区沉积物氮分为转化态氮(TF-N)和非转化态氮,并将可转化态氮区分为4种形态:离子交换态氮IEF-N 、碳酸盐结合态氮CF-N 、铁锰氧化态氮IMOF-N及有机态和硫化物结合态氮OSF-N。 对各形态氮的平面、垂直和沉积剖面年际分布进行了分析,并进一步探讨了该区域氮形态与古生产力的替代指标——生物硅(BSi)的相关性,揭示了氮形态的地球化学特征及与浮游植物总量的关系。结果表明,黄海、东海陆架区表层沉积物中可转化态氮占总氮的百分比为16.81%,可转化态氮中4种形态氮的平均含量为:IMOF-N(66.65 μg/g)>IEF-N(22.96 μg/g)>OSF-N(17.40 μg/g)>CF-N(11.26 μg/g),IMOF-N是可转化态氮的优势形态;柱状沉积物中各形态氮垂直分布不同,长江口沉积物中各形态氮垂向变化幅度大于南黄海中部;离子交换态氮IEF-N和铁锰氧化态氮IMOF-N对浮游植物总量贡献较大。     

Marine strategy framework directive: Defining joint monitoring opportunities for the Eastern Mediterranean and the Black Sea,through dedicated decision making workshops and innovative policy tools

The Marine Strategy Framework Directive (MSFD) is an important milestone for the preservation of the European marine environment. However, Member States can find its monitoring requirements challenging, particularly where it regards the definition and implementation of joint monitoring programmes between neighbouring countries. The challenges are even greater in the Mediterranean and the Black Sea, where many countries are not members of the European Union and where Regional Sea Conventions face greater difficulties in coordinating monitoring activities. This paper presents the results from two regional workshops, within the framework of IRIS-SES project, which aimed to inform policy- and decision-makers in the Eastern Mediterranean and the Black Sea on what key stakeholders, including scientists, academia and local authorities, consider the main gaps, needs and opportunities for the MSFD joint monitoring regarding eutrophication and contaminants. It shows that a bottom-up approach, guided by structured workshops, can be a successful means of enhancing cooperation.