Marine organic geochemistry of the Eastern Mediterranean: 1. Aliphatic and polyaromatic hydrocarbons in Cretan Sea surficial sediments

As part of a lipid biogeochemical study, aliphatic and polyaromatic hydrocarbons were determined in surficial sediments from the Cretan Sea (South Aegean Sea) in the Eastern Mediterranean. Total concentrations of both aliphatic (AHC) and polyaromatic (PAH) hydrocarbons were low (562–5697 and 14.6–158.5 ng/g, respectively) with respect to other coastal sediments worldwide and compare with concentrations found in open sea areas. The composition of AHC was dominated by unresolved complex mixture (UCM) indicating the presence of petroleum-related hydrocarbon inputs as confirmed by the detection of specific α,β-hopanes. PAH consisted mainly of pyrolytic four- to five-ring compounds. UCM and PAH amounts revealed that Cretan Sea receives low supply of anthropogenic material compared to NW Mediterranean. The spatial distributions of AHC and PAH indicated that urban run-off and transport from the continental self are the major input pathway of anthropogenic and biogenic hydrocarbons from terrestrial sources in the near shore area, whereas atmospheric transport might be the significant source of hydrocarbons in the deep area.     

Responses of macrobenthic communities to patchy distributions of heavy metals and petroleum hydrocarbons in sediments:A study in China's Zhoushan Archipelago

This study conducted four cruises during 2014–2017 to investigate relationships between macrobenthic communities and sediment contaminations in sea area around the Zhoushan Archipelago. Fourteen sites were categorized into three groups: high total heavy metal contamination content(HHMC), high total petroleum hydrocarbon content(HTPH), and low content ratio of heavy metal contamination content to total petroleum hydrocarbon content(HMC/TPH) areas. Four main taxa of macrofauna(polychaetes, bivalves, gastropods, and crustaceans) were determined to respond to environmental factors differently. While tolerant polychaetes being the minimal impact by environmental factors, bivalves were threated by heavy metal pollutions in sediment.Additionally, body size distribution frequency demonstrated that macrofauna in the low HMC/TPH areas were less disturbed by contamination than those in the HHMC and HTPH areas. The result represented the presentation of sensitive species while tolerant species are usually considered as small size organisms. Overall,this study confirmed the hypothesis that the contamination levels of small-scale patches is indicated by the condition of macrobenthic communities.     

广西钦州湾大型底栖动物生态特征及其与沉积物环境的相关性研究

为研究钦州湾大型底栖动物的生态特征,探讨影响大型底栖动物分布的主要因素,于2011年5月在钦州湾进行大型底栖动物调查,并同步采集沉积物样品,进行理化性质分析。使用Surfer软件绘制各群落特征指数的平面分布图,用SPSS软件分析群落特征指数与沉积物环境因子之间的关联性。共采集到大型底栖动物种类55种。平均生物量为105.48 g/m2,平均密度为50ind/m2。香农-维纳指数(H')、种类均匀度指数(J')和丰富度指数(D)的平均值分别为1.44,0.63和0.64。群落特征指数与沉积物环境因子之间的相关性分析结果显示,密度与Cu,Pb,Zn,Cd,Cr,Hg以及有机碳呈显著负相关;种类数与所分析的10项沉积物环境因子之间均呈显著负相关;均匀度指数与Hg和有机碳呈显著负相关;丰富度指数与硫化物呈显著负相关;生物量和香农-威纳指数与沉积物各环境因子之间均没有显著的相关性。     

The effect of a natural water-movement related disturbance on the structure of meiofauna and macrofauna communities in the intertidal sand flat of Rocas Atoll (NE, Brazil)

Rocas, the only atoll in the South Atlantic, is located 266 km off the northeast Brazilian coast. Spatial patterns in community structure of meiofauna, particularly nematodes, and macrofauna were examined along a transect through the sediment path from windward to leeward of the Rocas Atoll sand flat. Differences in benthic community structure between four zones of the sand flat were found to be significant and related to the major local processes of carbonate-grain transport and sedimentation. Both meiobenthic and macrobenthic assemblages were significantly more diverse and abundant within the sediment inflow zone (the initial part of the detrital path of Rocas sand flat) than in the other zones, where a clear impoverishment of benthic invertebrates occurred. This first study of the benthos of an intertidal sand flat over a reef island in the Atlantic showed that the meiofauna is numerically dominated by the nematodes Metoncholainussp. 1 (Oncholaimidae) and Epsilonema sp. 1 (Epsilonematidade), whilst the macrofauna is largely dominated by oligochaetes and large Oncholaimidae nematodes. Analysis of the species composition, trophic structure and abundance of both the meiobenthos and the macrobenthos revealed an impoverished community subjected to an intense water-movement disturbance.     

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.     

2010年5月与2013年6月黄、渤海大型底栖动物群落组成和结构的比较研究

基于2010年5月和2013年6月采集的黄、渤海海域的大型底栖动物数据,对该海域大型底栖动物的种类组成和群落结构等进行了研究,对该海域大型底栖动物群落结构的时间和空间差异进行了分析,并利用AMBI和m-AMBI生物指数对各站位的生态质量状况进行了评估。研究结果表明:在2010年5月和2013年6月所采站位的大型底栖动物共有131种,其中软体动物和甲壳动物占据了较大比例的物种数量,分别为51种和42种;其次为鱼类、多毛类和棘皮动物。该海域的优势物种为日本鼓虾 Alpheus japonicus、日本褐虾 Crangon hakodatei、司氏盖蛇尾Stegophiura sladeni和奇异指纹蛤Acila mirabilis,其中司氏盖蛇尾具有最大的丰度和优势度。生物指数(AMBI和m-AMBI)的结果显示黄、渤海区域底栖生态环境仍相对稳定,但与历史资料比较得知,该海域大型底栖动物生存环境整体趋于恶化。     

Biodiversity and seasonal variation of benthic macrofauna in Minicoy Island, Lakshadweep, India

From the Indian coast only limited data are available on the benthic fauna of the seagrass communities. In this study, seasonal variation in the distribution of macrobenthos and influence of environmental parameters was explored at four seagrass beds and two mangrove stations along the Minicoy Island, Lakshadweep, India, from September 1999 to August 2001. A total of 160 macrobenthic species from eight major groups represented the macrofauna of the Minicoy Island. Of the identified taxa, molluscs 70（gastropods 41.46%, bivalves 7.5%）, polychaetes 27（16.88%）, crustaceans 30（18.75%）, echinoderms 11（6.88%） and remaining others. Average seasonal abundance of benthic macrofauna ranged from 219 to 711 ind./m2, species diversity varied from 1.45 to 3.64 bits per individual, species richness index ranged from 4.01 to 26.17, evenness 0.69 to 1.66. In general, the higher abundance and species diversity was noticed in southern seagrass stations and northern seagrass stations, but in the mangrove stations comparatively low species diversity was observed. Three-way analysis of variance indicated that all communities resulted as being significantly different between seagrass and mangrove station, mainly when the seasonal interaction was considered. Multivariate analyses were employed to help define benthic characteristic and the relationship between environmental parameters at the six monitoring stations. Results of cluster analyses and multidimensional scale plot suggest that for mangrove region, different physiographic provinces, lower salinity, dissolved oxygen and sediment biotic structure have a higher influence on the species composition and diversity than other oceanographic conditions.     

底质细化对厦门潮下带文昌鱼栖息地大型底栖动物群落的影响

本文根据2014年至2017年在厦门文昌鱼保护区黄厝、南线十八线、鳄鱼屿和小嶝岛四处潮下带以及参照点白城潮下带获得的大型底栖动物和沉积物粒径数据,探讨底质细化对厦门潮下带文昌鱼栖息地大型底栖动物群落的影响。聚类分析表明个别黏土含量较高的取样站没有发现文昌鱼且大型底栖动物种数少。单因素方差分析表明,厦门潮下带部分大型底栖动物群落参数和优势种数量存在显著差异。底质粒径分析表明, 2017年9月,鳄鱼屿和白城潮下带黏土和粉砂含量高于黄厝、南线十八线和小嶝岛潮下带的黏土和粉砂含量。2016年夏季黄厝、南线十八线潮下带黏土和粉砂含量明显高于2014年夏季的黏土和粉砂含量。相关分析表明,5个大型底栖动物群落参数如物种数、栖息密度、生物量、多样性指数(H′)和丰度指数(d), 7个常见种的栖息密度和生物量与粉砂和黏土含量呈显著正相关,均匀度指数(J)和4种常见种的数量与粉砂和黏土含量无显著相关,白氏文昌鱼(Branchiostoma belcheri)的栖息密度和生物量与粉砂和黏土含量呈显著负相关。上述结果证实,黏土含量增加到15%和粉砂含量增加到60%有利于多数大型底栖动物栖息密度和生物量的增加,...     

青岛近海大型底栖动物生物多样性现状

根据2007年1月、4月和10月对青岛近海15个站位3个航次的调查资料,初步分析了青岛近海大型底栖动物的物种多样性现状,以种类组成、生物量和栖息密度为基础,应用香农-威纳指数、物种丰富度指数以及物种均匀度指数对青岛近海大型底栖生物的群落结构、种类组成、优势种以及数量动态趋势进行了分析。结果表明:本次调查共采到底栖动物226种,其中多毛类119种,甲壳动物58种,软体动物23种,棘皮动物12种。各站种类数在2~52种之间,种类最少的出现在海域东北部的S2站,最多的出现在西南部的S15站。各站物种多样性指数差别较大,最大的为10月的S12站,最小的为1月S2站。物种丰富度的季节变化较显著,物种多样性和物种均匀度季节变化不显著。     

Seagrass colonization: Knock-on effects on zoobenthic community,populations and individual health

This study provided evidence that Zostera noltii presence affects macrofauna community structure independently from median sediment grain-size and that the notion of ecosystem health is rather subjective: in the present case, we recorded “good health” in terms of seagrass development, “no impact” in terms of macrobenthic biotic indices and “negative effect” for a given key-population. The occurrence and development of a Z. noltii seagrass bed was surveyed at Banc d’Arguin, Arcachon Bay (France), to estimate the modification of the macrozoobenthic community and of the dynamics of a key-population for the local ecosystem, – the cockle Cerastoderma edule. Even though median grain-size of the sediment decreased only at the very end of the survey, i.e. when seagrass totally invaded the area, most of the macrofauna community characteristics (such as abundance and biomass) increased as soon as Z. noltii patches appeared. The structure of the macrofauna community also immediately diverged between sand and seagrass habitats, without however modifying the tested biotic indices (BENTIX, BOPA, AMBI). The health of the cockle population (growth, abundance, recruitment) was impacted by seagrass development. Related parasite communities slowly diverged between habitats, with more parasites in the cockles from seagrass areas. However, the number of parasites per cockle was always insufficient to alter cockle fitness.     

Recovery of the macrobenthic community in the Valli di Comacchio,northern Adriatic Sea,Italy

The macrobenthic community structure of the Valli di Comacchio (northern Italy) was described in order to assess the ecological conditions of the main basins through 2001. In addition, the biotic data set gathered in 1997–1998 was compared to achieve an estimation of the eventual recovery of the lagoonal benthic assemblages. Four permanent sites (P1, M4, M5 and M6), located along a gradient of sediment texture and confinement, and representing four different areas of the lagoon, were sampled quarterly in 2001 for macrofauna and sedimentary variables (organic content, phytobenthic chlorophyll-a, depth of the redox potential discontinuity layer), and fortnightly for water variables (temperature, salinity, dissolved oxygen and planktonic chlorophyll-a). Water and sedimentary variables were typical of eutrophic areas. A total of 52 macrobenthic taxa were identified and, on the basis of the species collected, differences in faunal distribution among the four areas were recognized, although less marked than in previous studies. Sediment trophic status and its seasonal dynamics in the Valli were crucial in determining species distribution among the different areas. The comparison between 1997–1998 and 2001 biotic data indicated that conditions in the lagoon had improved, especially in the formerly most impaired, central area. In the Valli di Comacchio, the recovery of benthic communities after severe disturbance will probably take longer, even if sewage discharges have been removed 11 years ago. Secondary disturbance due to scarce water circulation, sharp temperature and salinity fluctuations, release of toxic substances from sediments influenced animal assemblages along spatial and temporal scales. The interplay of these variables probably caused deviations from the expected improvement in benthic conditions. Nevertheless, clear signs of amelioration, particularly at the previously most impaired area, were detectable.     

Overview of the recent sediment hydrocarbon geochemistry of Atlantic and Gulf Coast outer continental shelf environments

An overview of the hydrocarbon geochemistry of recent marine sediments from the U.S. Atlantic and Gulf of Mexico Outer Continental Shelf (OCS) regions is presented. Hydrocarbon levels along the Atlantic OCS are fairly uniform, ranging between <0·1 and 20 ppm, with the higher values occurring in areas of fine-grained sediment accumulation. Elevated hydrocarbon concentrations appear to be associated with anthropogenic inputs of silt/clay-sized particles to OCS sediments via particulate resuspension and transport, as evidenced by an increase in contributions from the unresolved complex mixture (UCM) feature in gas chromatograms. Compositional characteristics of hydrocarbons in the high-carbonate sediments of the Eastern Gulf OCS indicate a primarily marine origin. Proceeding north and west along the shelf, sedimentary hydrocarbons assume a more terrestrial and/or anthropogenic character in response to a greater input of silt/clays from the Mississippi River. Highest hydrocarbon concentrations in this region (up to 70 ppm) are found in the shallow nearshore areas west of the Mississippi River discharge and in the vicinity of Galveston Bay along the South Texas OCS.In the North Atlantic, Eastern Gulf, South Texas Gulf and coastal Louisiana sediments a linear relationship exists between total hydrocarbon and total organic carbon concentrations, indicating that each area consists of a geochemical ‘province’ defined by a source input or depositional regime specific to the region. The use of trace parameter/bulk parameter ratios (such as total hydrocarbon or individual PAH concentrations/total organic carbon content) in defining such provinces, and thus in serving as a basis for evaluating variations in source inputs as part of future surveys, is demonstrated. This approach views the hydrocarbon content and composition of Atlantic and Gulf coast OCS sediments as points on a spectrum defined by input types (sources) and deposition patterns (sedimentation and erosion), which conceptually link all the regions into a unified system.     

Contemporary condition of macrozoobenthos in ultrashallow zone of Taman Bay,Sea of Azov

The distribution of macrozoobenthic communities was studied in a vast ultrashallow (0–1.2 m deep) zone of northwestern Taman Bay (separated from the Kerch Strait by Chushka spit) in 2008–2009. Fifty-two species of benthic invertebrates were recorded. The species number, as well as Shannon and Pielou diversity indices, increased along Chushka spit from base to tip. The usual inhabitants of lagoons and estuaries of the Mediterranean Basin and the open Sea of Azov dominated in benthic communities: mollusks Abra segmentum and Hydrobia acuta and polychaetes Heteromastus filiformis and Hediste diversicolor (the latter only in summer). Changes in the community structure were largely determined by the seasonal dynamics of dominant species populations, which was similar to their dynamics in certainother transitional water bodies of the Mediterranean Basin. These changes indicate normal running of seasonal processes in the macrobenthic communities of Taman Bay in 2008 rather than the consequences of a catastrophic black oil spill in the Kerch Strait in November 2007.     

Ecosystem health of Montevideo coastal zone: A multi approach using some different benthic indicators to improve a ten-year-ago assessment

A study on the benthic ecosystem health was performed to assess the environmental quality of Montevideo coastal zone, in view of the construction of a new sanitation system. Data were compared to previous research undertaken 10 years ago, and biochemical composition of organic matter, heavy metals, organic matter, phytopigments, benthic diatoms, macrofauna community structure and a biotic index (AMBI) were used as proxies. Results indicate an environmental quality-gradient, with the worst conditions within the inner stations of Montevideo Bay and an improvement towards the adjacent coastal zone. Higher levels of chromium, lead, phaeopigments, organic biopolymers and poor benthic macrofauna and diatom communities, characterised the hypertrophic innermost portion of Montevideo Bay. Data indicated a clear deterioration of the adjacent coastal zone comparatively to that observed 10 years ago. The complementary use of approaches not applied before (benthic diatoms and organic biopolymers) with those formerly applied improve our assessment of the trophic status and the environmental health of the area.     

Structural and functional shifts in zoobenthos induced by organic enrichment — Implications for community recovery potential

Habitat change induced by organic enrichment is a growing concern for the sustainability of benthic communities in coastal aquatic environments. This case study describes the spatial and temporal response patterns and the recovery potential of low-diversity benthic communities to organic enrichment at two fish farm locations, during the rearing periods (15 and 20 years, respectively) and the following recovery periods (2 years). The spatial extent of disturbance differed depending on the hydromorphological characteristics of the rearing sites, but degraded macrobenthic communities close to both fish farms were recorded soon after the activity started. Continued organic enrichment resulted in high species turnover-rates and in an altered benthic community composition at both locations. After fish farm abatement, a partial recovery was detected in species richness, but abundance and biomass values were reduced and changes in structural composition remained. Alterations in benthic biological traits were observed at both fish farm locations, implying that organic enrichment might cause changes in benthic community function within low-diversity benthic communities.     

山东宁津附近海域大型底栖动物群落结构及季节变化

根据2009年11月至2010年8月在山东宁津附近海域进行4个季度月航次调查所得大型底栖动物采泥资料,运用优势度指数、物种多样性指数及Cluster聚类和MDS排序等方法,分析了该海域的大型底栖动物群落特征和季节变化。结果表明:4个航次在底泥样品中共鉴定大型底栖生物11门159种,其中,多毛类动物73种,是主要的优势类群,甲壳动物39种,软体动物25种,棘皮动物9种,其他类群共13种。主要优势种有拟特须虫、丝异蚓虫、索沙蚕、轮双眼钩虾等。宁津邻近海域年平均生物量和丰度分别为9.144g/m~2和233.90ind./m~2,均较低且存在季节性差异。丰富度指数(D)、均匀度指数(J)和多样性指数(H′)的年平均值分别为2.436、0.800和2.924,次级生产力较低,平均值仅为1.903g(AFDW)/(m~2·a)。聚类分析结果表明,秋、春航次群落分布格局均包含近岸群落和远岸群落,但各群落间界线不明显,群落结构受扰动情况不明显。     

桑沟湾大型底栖动物生物多样性研究

为了解桑沟湾大型底栖动物多样性现状,作者于2009年7月和12月对桑沟湾9个站位进行2个航次的采样,以种类组成、生物量和栖息密度为基础,采用物种多样性指数(Shannon-Wiener index)、物种丰富度指数(Species richnessindex)以及物种均匀度指数(Species evenness index)对大型底栖动物多样性及其影响因子进行了分析。结果表明:共采到大型底栖动物83种,其中多毛类45种,占种类总数的54.22%,软体动物11种(占13.25%),甲壳类23种(占27.71%),其他4种(占4.82%)。各站获得平均种类数在2～28种之间,种类最少的出现在夏季的C8站,最多的出现在夏季的C4站。不同养殖区生物多样性指数差异也很大,物种多样性(H′)和物种丰富度指数(D)均以贝类养殖区最高,藻类养殖区最低,而物种均匀度指数(J′)以贝藻混养区最高,藻类养殖区最低。生物多样性除了受种的数量及其个体密度的影响外,还与多种环境因素有关,相关性分析结果表明:水温、盐度、沉积物类型和硫化物含量是影响桑沟湾大型底栖动物生物多样性的主要环境因子。     

Changes in Dogger Bank macrofauna communities in the 20th century caused by fishing and climate

The macrofauna communities on the Dogger Bank (North Sea) from the 1920s, the 1950s and the 1980s to the 2000s were compared and identified five communities with similar spatial distribution throughout the 20th century. The abundance of dominant species in the five communities varied with time. Most obvious in the 1950s was the loss of the extensive Spisula and Mactra patches, which covered most of the shallow parts of the Bank in the 1920s. Since the 1980s, they have been found only as juveniles. The biological regime shift in the late 1980s caused an increase in macrofauna abundance, species numbers, diversity and southern species in most of the communities. The climate regime shift in 2001 had opposite effects in which the abundance, species numbers, diversity and southern species decreased in most of the communities. The increase in interface-feeding species and the decrease in sand-licking amphipods in the 2000s especially in the shallow Bank Community give evidence for climate driven changes in water masses, currents, storms, turbidity and food availability via planktonic or benthic primary production. Both fishing impact and climate change are hypothesised as explaining the changes in the Dogger Bank macrofauna communities.     

胶州湾西北部海域大型底栖动物群落研究

自2003年9月~2004年9月在胶州湾西北部养殖区内外隔月取样,共获得7个航次的大型底栖动物样品。用PRIMER软件对大型底栖动物群落进行分析,结果表明:养殖区内站位的丰度值、生物量及群落结构与外面站位差别较大,经相关检验站位之间差异显著,说明养殖区内因为养殖活动已经引起大型底栖生物的剧烈扰动;还发现胶州湾养西北部海域群落种类组成季节变化明显,与历史资料相比,棘皮动物数量明显减少,软体动物特别是菲律宾蛤仔是胶州湾大型底栖动物生物量的主要贡献种。根据LUSTER聚类和MDS标序的结果,把底栖生物群落划分为四大生物组。比较发现,胶州湾西北部及附近海域大型底栖生物群落已经发生了变化,通过对底栖生物群落与环境因子的分析认为,造成变动的原因可能是渔业活动的加剧和湾内水体污染的压力。     

Respiration partitioning in contrasting subtidal sediments: seasonality and response to a spring phytoplankton deposition

Biomass and respiration rates of bacteria, nematodes and macrobenthos were estimated in relation to the deposition of the spring phytoplankton bloom at two contrasting sites in the Southern North Sea: one with fine‐grained sediment close to the coastline and another with highly permeable sediments. Sediment community oxygen consumption (SCOC) was also measured. Bacterial biomass was relatively similar at both stations, whereas nematode and macrobenthic biomass were higher in fine‐grained sediment. In fine sediments, bacterial biomass increased quickly after deposition of the phytoplankton bloom, whereas the response of nematodes and macrobenthos was delayed. In coarser sediments, nematodes and macrobenthos also showed a fast response in terms of density and biomass. Respiration in permeable sediments was mainly dominated by bacteria at all periods of the year. Hence, nematode and macrobenthic respiration did not contribute strongly to SCOC. This is in contrast to the patterns observed in finer sediments, where both macrofauna and nematodes were important oxygen consumers as well. Macrobenthos contributed more to total SCOC than did nematodes in winter. However, shortly after the arrival of phytodetritus at the sea floor, nematodes and macrobenthos contributed equally to the total SCOC, indicating that all benthic size classes should be taken into account when investigating marine benthic respiration rates.