[Growth characteristic of statolith of Todarodes pacificus in the East China Sea in the La Niña year]. / 拉尼娜发生期东海太平洋褶柔鱼耳石生长特征.

To investigate the differences on morphological growth patterns of statolith of Todarodes pacificus in the East China Sea during La Niña and normal years, we analyzed the samples of T. pacificus collected in the East China Sea by Chinese light purse seine fishery fleets from February to April in 2020 (a normal year) and 2021 (a La Niña year). The results showed that total statolith length (TSL), lateral dome length (LDL), wing length (WL), and maximum width (MW) could be used as characterization parameters to representing the morphological growth of statolith. The characterization parameters of statolith in T. pacificus differed significantly between different climate years and between different genders. The values of those characterization parameters of statolith were greater in normal year than those in La Niña year, which in both years were larger in females, except for TSL in males in La Niña year. The statolith growth of males were faster than that of females in different climate years. TSL, LDL, and WL increased faster in normal year, while MW increased faster in La Niña year. The relative size of statolith gradually slowed down with the growth of individuals.

Distribution and influencing factors of atmospheric nitrogen oxides (NOx) over the east coast of China in spring: Indication of the sea as a sink of the atmospheric NOx.

An integrated observation of NOx that included coastal cities and oceanic cruises covering the Qingdao coastal waters sites (QDCW) and the Yellow Sea and East China Sea sites (YECS) was conducted in spring. The average concentrations of the coastal cities, the QDCW, and the YECS were 5.4 ± 4.1, 4.2 ± 3.5, and 2.9 ± 6.8 ppb for NO while 18.5 ± 7.2, 9.4 ± 5.2, and 4.9 ± 6.4 ppb for NO2, depicting lowest levels in the open seas. Atmospheric NO and NO2 showed similar spatial variations over the seas, the stations where the air masses originated from land or nearshore regions showed higher levels, but the decisive influencing factors were not the same in the different study areas. The calculated NOx flux value in the YECS (-8.7 × 10-17 mol N cm-2) indicated that the sea surface was a net sink of atmospheric NOx.

The influence of emerging atmospheric organophosphorus flame retardants from land source emissions on the East China Sea.

Organophosphate flame retardants (OPFRs) pose a new challenge to the marine environment due to their toxicity and persistence. This study explores the contributions of OPFR emissions from different land sources and sectors to its contamination of the East China Sea (ECS) using a novel atmospheric transport model（ChnMETOP）for POPs and a marine food web model. The results show that the major land sources causing OPFR pollution in the ECS were situated in Yangtze River Delta (YRD) and middle reach areas of China's Yangtze River, confirming that source proximity made most significant contributions to OPFR pollution in the ECS. Among those OPFR emission sectors, industrial emissions accounted for the highest modeled OPFR levels in the seawaters, followed by the OPFR usage process in textile, plastic, and rubber products. Assessment of bioaccumulation of OPFR in the marine food web of the ECS and the potential risk in commercial fish consumers reveals lower exposure risk via dietary fish ingestion. However, the risk might increase if OPFRs are continuously bioaccumulated in the biotic and released into the abiotic marine environment. This study simultaneously identified both the source locations and emission sectors, thereby providing important policy implications in mitigating OPFR pollution in the ECS marine environment.

Metabarcoding of harmful algal bloom species in sediments from four coastal areas of the southeast China.

In the past three decades, harmful algal blooms (HAB) have become more frequent and widespread in southeast Chinese sea areas. Resting stages are regarded as the "seed bank" of algal blooms, and play an important role in initiating HABs. The distribution of resting stages in sediments especially those of HAB species can make good predictions about the potential risk of future blooms, however with limited reports. In this study, surface sediment samples were collected in the four sea areas along the southeast Chinese coasts, including Dafeng Port (DF) in the southern Yellow Sea, Xiangshan Bay (XS), Funing Bay (FN), and Dongshan Bay (DS) in the East China Sea. Diversity and community structure of eukaryotic microalgae in surface sediments were assessed by metabarcoding V4 region of the 18S rDNA, focusing on the distribution of HAB species. Biogenic elements including total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), biogenic silicon (BSi), and moisture content (MC) were analyzed. A total of 454 eukaryotic algal OTUs were detected, which belonged to 31 classes of 9 phyla. Altogether 149 algal species were detected in this study, and 59 taxa have been reported to form resting stages. Eukaryotic algal community was similar in XS, FN and DS of the East China Sea, which were predominated by dinoflagellates. However, algal community was different in DF of the Yellow Sea, and characterized by the dominance of chrysophytes and low OTU richness. The distribution of most abundant HAB species showed positive correlations with TN, BSi, and TOC, suggesting that eutrophication and consequent increase in diatom productivity may have a significant influence on the distribution of HAB species and facilitate the occurrence of HABs. Furthermore, HAB species occurred more abundantly and widely in FN. Our results suggest high potential risks of HABs in the southeast Chinese coast especially in Funing Bay.

Prevalence of small-sized microplastics in coastal sediments detected by multipoint confocal micro-Raman spectrum scanning.

Microplastics have become global emerging issue and received widespread attention in recent years. Due to their chemical persistence, plastic particles can be broken into smaller items but accumulated for long time in the environment like sediment. However, limited by current detection technologies, the distribution and characteristics of small-sized microplastics in coastal sediment remain uncertain. In this study, we established a new method based on micro-Raman spectroscopy for detecting small-sized microplastics, namely multipoint confocal micro-Raman spectrum scanning (MCmRSS). The MCmRSS was first applied in detecting microplastics in the sediment samples collected from three bays of the East China Sea. The minimum size of microplastics was 4 µm and average microplastics concentration was 91 ± 55 items /g dry weight sediment, with fragment and polyethylene as the most common shape and polymer type, respectively. The spatial variation of microplastics was in accordance with the strength of coastal human activities and marine dynamics. In all the microplastic items, the small-sized ones (<10 µm) accounted for 67%; and the relationship between microplastic concentration and its size followed a power-exponential equation. Compared with previous studies, the number of microplastics in coastal sediments detected by the MCmRSS increased by 2 orders of magnitude, which was benefited from the advantages of multipoint scanning in the fixed identification areas and high resolution of micro-Raman spectrum. Our findings would summon the re-evaluation of the potential risks of small-sized microplastics in the coastal environment.

The complete mitochondrial genome of Crassostrea hongkongensis from East China Sea indicates species' range may extend northward.

BACKGROUND: Crassostrea hongkongensis is an important mariculture shellfish with a relatively narrow distribution range. Recently, larger wild oysters were identified as C. hongkongensis from Sanmen bay in East China Sea. No natural distribution had been reported for this species here, and its origin remains unknown. METHODS AND RESULTS: We assembled the complete 18,617 bp circular mitochondrial genome of C. hongkongensis from Sanmen bay by next generation sequencing. It included 12 protein-coding genes, 23 tRNAs, and two rRNAs. The A/T content of the mitogenome was higher than its G/C content. Similar values and features were previously found for five other specimens of C. hongkongensis, and were comparable to those of other congeneric species. A phylogenetic analysis based on the 12 protein-coding genes and complete mitochondrial sequence indicated that the six specimens of C. hongkongensis formed a monophyletic group and shared a sister group relationship with C. ariakensis, C. nippona, C. sikamea, C. angulata, C. gigas, and C. iredalei, whereas specimens from the Sanmen bay area clustered later with the five other C. hongkongensis individuals, sharing a sub-clade. The newly sequenced mitogenome had more singleton sites than previously published C. hongkongensis mitogenomes. CONCLUSIONS: Crassostrea hongkongensis may be a native species, and the species' range extends further to the north than previously known. Our data may therefore contribute to a better understanding of the species diversity and conservation of Crassostrea oysters.

Budget of riverine nitrogen over the East China Sea shelf.

Riverine nitrogen loading to the continental shelf sea is important for terrestrial-marine linkage and global nitrogen cycling and leads to serious marine environmental problems. The budget and cycle of riverine nitrogen over the continental shelf in the East China Sea (ECS) are unknown. Using the tracking technique within a physical-biological coupled model, we quantified the nitrogen budgets of riverine dissolved inorganic nitrogen (DIN) and particulate organic nitrogen (PON) over seasonal to annual scales in the ECS, especially from the Changjiang River, which plays a dominant role in riverine nitrogen input. The horizontal distributions of the Changjiang DIN and PON generally followed the Changjiang diluted water and coastal currents and were affected by stratification in the vertical direction. Their inventory variations were dominated by biological fluxes and modulated by physical ones, and changed most dramatically in the inner shelf among three subregions. Less than half of DIN were converted to PON with most of the rest leaving the ECS through lateral transport pathways, among which the flux through the Tsushima Strait was dominant. With the increasing loading of the Changjiang DIN flux from the 1980s-2010s, lateral transports rather than PON production increased due to limited primary production. Approximately 60 % of the produced PON exported to the sediment and 34 % went to the Tsushima Strait. According to the export production, the DIN from the Changjiang River contributed 12-42 % to the ECS carbon sequestration.

Multidecadal records of microplastic accumulation in the coastal sediments of the East China Sea.

Microplastics are an emerging hazard in the marine environment, and considered to eventually sink into sediments. An investigation into the long-term variation of microplastic accumulation in sediment cores is essential for understanding the historical trend of this contamination and its response to human activities. In this study, the multidecadal changes of microplastic abundances in two sediment cores from the inner shelf of the East China Sea (ECS) were revealed by two methods, i.e., a visual enumeration method based on scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and a quantitative method based on microplastic-derived carbon (MPC) abundances. The features of microplastics were determined via SEM-EDS and micro-Fourier transform infrared spectroscopy (µ-FTIR). The results reveal a multidecadal increasing trend of microplastic accumulation in the coastal sediments of the ECS since the 1960s, which may be jointly governed by the release of plastic wastes and oceanographic dynamics. Meanwhile, the breakpoint of the exponential growth of microplastics in the ECS occurs in 2000 AD, which well matches the rapid increasing of plastic production and consumption in China. Further, based on the MPC contents in sediments, the influence of microplastics on the quantitative evaluation of carbon storage in the ECS has been examined for the first time, revealing an insignificant (<2% before 2014 AD) but potentially-increasing (6.8% by 2025 AD) contribution of microplastics to carbon burial. Our results may provide the important data for evaluating and mitigating the impact of microplastics on the marine environment.

Distribution of eight organophosphorus pesticides and their oxides in surface water of the East China Sea based on high volume solid phase extraction method.

In this study, we reported the occurrence of eight organophosphorus pesticides (OPPs) in the East China Sea. Forty samples were collected and analysed with a high volume solid phase extraction method (Hi-throat/Hi-volume SPE) in the early summer of 2020. All the target OPPs were detected in the surface water at one or more stations in the East China Sea, and the concentrations of ΣOPPs were in the range 0.0775-3.09 ng/L (mean: 0.862 ± 0.624 ng/L). Terbufos sulfone and fenthion were the main pollutants in this area, probably resulting from pesticide use in China and other countries. The off-shore input from coastal regions was suggested to be a major source of OPP pollution in the East China Sea, and the movement of ocean currents played an important role in their transportation because around 0.86 t OPPs passed through the Tsushima Strait from the East China Sea each month. An ecological risk assessment showed that these OPPs presented a high risk to species in the East China Sea, whereas they posed no health risk to humans under both the median and high exposure scenario.

Occurance, emission and environmental effects of non-methane hydrocarbons in the Yellow Sea and the East China Sea.

The spatial distributions, fluxes, and environmental effects of non-methane hydrocarbons (NMHCs) were investigated in the Yellow Sea (YS) and the East China Sea (ECS) in spring. The average concentrations of ethane, propane, i-/n-butane, ethylene, propylene and isoprene in the seawater were 18.1 ± 6.4, 15.4 ± 4.7, 6.8 ± 2.9, 6.4 ± 3.2, 67.1 ± 26.7, 20.5 ± 8.7 and 17.1 ± 11.1 pmol L-1, respectively. The alkenes in the surface seawater were more abundant than their saturated homologs and NMHCs concentrations (with the exception of isoprene) decreased with carbon number. The spatial variations of isoprene were consistent with the distributions of chlorophyll a (Chl-a) and Chaetoceros, Skeletonema, Nitzschia mainly contributed to the production of isoprene, while the others' distributions might be related to their photochemical production. Observations in atmospheric NMHCs indicated alkanes in the marine atmosphere decreased from inshore to offshore due to influence of the continental emissions, while alkenes were largely derived from the oceanic source. In addition, no apparent diurnal discrepancy of atmospheric NMHCs (except for isoprene) were found between daytime and night. As the main sink of NMHCs in seawater, the average sea-to-air fluxes of ethane, propane, i-/n-butane, ethylene and propylene were 31.70, 29.75, 18.49, 15.89, 239.6, 67.94 and 52.41 nmol m-2 d-1, respectively. The average annual emissions of isoprene accounted for 0.1-1.3% of the global ocean emissions, which indicated that the coastal and shelf areas might be significant sources of isoprene. Furthermore, this study represents the first effort to estimate the environmental effects caused by NMHCs over the YS and the ECS and the results demonstrated contributions of alkanes to ozone and secondary organic aerosol (SOA) formation were lower than those of the alkenes and the largest contributor was isoprene.

Radiolarian assemblages in the shelf area of the East China Sea and Yellow Sea and their ecological indication of the Kuroshio Current derivative branches.

We analyzed the radiolarian assemblages of 59 surface sediment samples collected from the Yellow Sea and East China Sea of the northwestern Pacific. In the study region, the Kuroshio Current and its derivative branches exerted a crucial impact on radiolarian composition and distribution. Radiolarians in the Yellow Sea shelf showed a quite low abundance as no tests were found in 15 of 25 Yellow Sea samples. Radiolarians in the East China Sea shelf could be divided into three regional groups: the East China Sea north region group, the East China Sea middle region group, and the East China Sea south region group. The results of the redundancy analysis suggested that the Sea Surface Temperature and Sea Surface Salinity were primary environmental variables explaining species-environment relationship. The gradients of temperature, salinity, and species diversity reflect the powerful influence of the Kuroshio Current in the study area.

Dataset for atmospheric transport of nutrients during a harmful algal bloom.

The data presented in this article are related to the research article entitled "Atmospheric transport of nutrient matter during a harmful algal bloom"[1]. These data provide the concentration of nutrients (nitrate, ammonium and FeⅡ) in the atmosphere and their deposited flux in the East China Sea prior to the harmful algal bloom on May 3-8, 2006. They can be helpful for analyzing the source of nutrients causing the harmful algal blooms.

Two Decades' Variation of Trace Elements in Bones of the Endangered East Asian Finless Porpoise (Neophocaena asaeorientalis sunameri) from the East China Sea, China.

There has been increasing concern about trace element accumulation in finless porpoises over the past decades, while the long-term variation of its concentration has been little known. Since most soft tissues of porpoises in the past were not preserved until now, the bone tissue is the only ideal material available. Here, 27 East Asian finless porpoise bone samples collected from Nantong, the East China Sea during two periods (1984-1992 and 2009) were used to explore the temporal variation of nine typical elements' concentration (Fe, Mn, Cu, Ni, Hg, Cr, Pb, As, and Cd, dry weight). An upward trend for total trace element accumulation from 329.04 mg/kg in 1984-1992 to 1535.81 mg/kg in 2009 was found; this could have resulted from the increasing industrial development in the Nantong region. The Mn, Fe, and As levels increased significantly while the concentrations of Cd, Cu, and Pb significantly decreased. Generally, our results suggested that most trace elements posed low threats to East Asian finless porpoises' health during both periods, while elements Mn (2009), Ni (both periods), Fe (2009), and As (2009) posed a potentially higher health risk to porpoises. Thus, the trace element levels warrant concern and continuous monitoring.

[Detection Method, Distribution, and Risk Assessment of Pharmaceuticals and Personal Care Products in the Yellow Sea and the East China Sea].

At present, research findings on pharmaceuticals and personal care products (PPCPs) in coastal areas are still unclear, and there is a need to develop a method to detect more PPCPs simultaneously in seawater. In this study, nine compounds of non-steroidal anti-inflammatory drugs, antibiotics, lipid regulators. and stimulants were selected as analytes. Solid phase extraction (SPE) was used to extract the compounds, which were then analyzed by high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS). The optimum experimental conditions, such as the filler, eluent, pH, flow rate, and the reduction of matrix effect were optimized during the SPE. The results showed that the best extraction column was CNW HLB, the best eluent was methanol:acetonitrile (1:1, volume ratio), the best eluent volume was 6 mL, the best pH was 7, the best flow rate was 5 mL·min-1, the amount of EDTA-Na2 added was 1 g, and the best concentration multiple was 500. The linear regression equations of all PPCPs had good linearity. Correlation coefficients were>0.999, recovery rates were between 82%-106%, relative standard deviations were between 1.6%-14%, and detection limits were between 0.01-2 ng·L-1, thus satisfying the requirement of trace analysis in seawater. Distribution characteristics and sources of PPCPs were studied in the Yellow Sea and the East China Sea during summer 2018. All nine PPCPs were detected and the main pollutants were NAP, IBU, GEM, CAF, and ASA. High concentrations of PPCPs were generally detected in the nearshore area and displayed conspicuous decreasing tendencies from the inshore towards the offshore. The concentrations of PPCPs in the Yellow Sea were higher than of those in the East China Sea, and this was related to there being more sources of pollutions and poor water exchange capacity in the Yellow Sea. Principal component analysis showed that the main source of PPCPs was terrestrial input. The environmental risk assessment of PPCPs indicated that risk quotients (RQs) of IBU and NAP (0.1-1) posed a medium risk to the aquatic environment, while others posed low risk to organisms.

Alkaline phosphatase activities and regulation in three harmful Prorocentrum species from the coastal waters of the East China Sea.

Harmful blooms of Prorocentrum donghaiense occur annually in the phosphorus-scarce coastal waters of the East China Sea (ECS). The enzymatic activities of alkaline phosphatase (AP) and its regulation by external phosphorus were studied during a P. donghaiense bloom in this area. The AP characteristics of P. donghaiense was further compared with Prorocentrum minimum and Prorocentrum micans in monocultures with both bulk and single-cell enzyme-labeled fluorescence AP assays. Concentrations of dissolved inorganic phosphorus (DIP) varied between 0.04 and 0.73 µmol l-1, with more than half recording stations registering concentrations below 0.10 µmol l-1. Concentrations of dissolved organic phosphorus (DOP) were comparable or even higher than those of DIP. P. donghaiense suffered phosphorus stress and expressed abundant AP, especially when DIP was lower than 0.10 µmol l-1. The AP activities showed a negative correlation with DIP but a positive correlation with DOP. The AP activities were also regulated by internal phosphorus pool. The sharp increase in AP activities was observed until cellular phosphorus was exhausted. Most AP of P. donghaiense was located on the cell surface and some were released into the water with time. Compared with P. minimum and P. micans, P. donghaiense showed a higher AP affinity for organic phosphorus substrates, a more efficient and energy-saving AP expression quantity as a response to phosphorus deficiency. The unique AP characteristic of P. donghaiense suggests that it benefits from the efficient utilization of DOP, and outcompete other species in the phosphorus-scarce ECS.

[Latitudinal variation in soil carbon, nitrogen and phosphorus pools across island forests and shrublands in eastern China]. / ä¸­å›½ä¸œéƒ¨æµ·å²›æ£®æž—å’ŒçŒä¸›åœŸå£¤ç¢³æ°®ç£·å »åˆ†åº“çš„çº¬åº¦å˜åŒ–.

Despite its monotonous structure, sea-island plays a crucial role in sustaining biodiversity and ecosystem functioning. The objectives of this study were to explore the altitudinal variation of soil carbon (C), nitrogen (N), and phosphorus (P) pools in forests across 14 islands spanning temperate zone (TZ), northern subtropical zone (NSZ), mid-subtropical zone (MSZ), and sou-thern subtropical zone (SSZ) in eastern China. The relationships of soil C and nutrient pools with climatic factors and plant species diversity were examined across islands. Our results showed that soil C, N and P pools differed significantly across climatic zones. Soil C and N pools were the lowest in TZ (49.35 and 1.08 t·hm-2) and the highest in NSZ (137.25 and 4.63 t·hm-2). Soil P pool was the lowest in SSZ (1.3 t·hm-2) and the highest in NSZ (5.19 t·hm-2). There were significant difference in soil C, N and P pools among vegetation types. Soil C, N and P pools in deciduous forests were significantly higher in subtropical than in temperate islands. Soil C and N pools in evergreen broadleaved forests did not differ among sub-climatic zones, and soil P pool was lower in SSZ than that in NSZ and MSZ. The interactions across mean annual temperature, mean annual precipitation, soil water content, and plant species diversity positively affected latitudinal variation in soil C, N, and P pools. Plant species diversity positively associated with soil N pool, but negatively linked with soil P pool. In conclusion, the latitudinal trend of soil C pool is different, but that of soil N and P pools are identical between sea-island and mainland. The main abiotic and biotic dri-vers of soil C, N and P pools are water availability, temperature and plant species diversity across sea-islands in eastern China.

Occurrence and distribution of antibiotic resistance genes in the sediments of the East China Sea bays.

The coastal area of the East China Sea has experienced rapid urbanization and industrialization in China since 1980s, resulting in severe pollution of its environments. Antibiotic resistance genes (ARGs) are regarded as a kind of emerging pollutant with potential high risk. The sediment samples were collected from Hangzhou Bay (HB), Xiangshan Bay (XB), and Taizhou Bay (TB) to investigate the spatial occurrence and distribution of 27 ARGs and class I integron-integrase gene (intI1) in the coastal area of the East China Sea. The PCR results showed the frequent presence of 11 ARGs and intI1 in the sediments of the three bays. The qPCR results further showed that sulfonamide resistance was the most prevalent ARG type and antibiotic target replacement and protection were the most important resistance mechanisms in the sediments. Regarding the subtype of ARGs, sulI, tetW, and dfrA13 were the most abundant ARGs, in which sulI was higher in TB (based on both the absolute and relative abundances) and dfrA13 was higher in HB (based on the relative abundances). The network analysis revealed that intI1 had significant correlations with tetC, sulI, sulII, and blaPSE-1. Oil was the key connected factor, which had positive connections with sulI, sulII, and blaPSE-1. In addition, the joint effect of heavy metals and nutrients & organic pollutants might be crucial for the fate of ARGs in the coastal sediments.

Distribution and composition of suspended matters in the wintertime in the East China Sea.

Total suspended matters (TSMs), as the sediment precursor, directly affect the mass exchange and sedimentation in the East China Sea (ECS). Ultrafine suspended matters (USMs) are an important component of the TSMs, and may play a significant role in regulating pollutant transfer and shaping biological communities. However, the conventional filtration may cause the loss of USMs because the filter membranes with the pore size of 0.45 µm were adopted to collect TSMs; and consequently, no data on USMs are currently available in continental shelves. In this study, the TSMs and USMs in the wintertime in the ECS were collected by using the filter membranes with the pore size of 0.22 µm for investigating their compositions, distributions and exchanges for the first time. The results show that the TSMs consisted of mineral particles (35-80%), biological fragments (10-50%), and flocs (10-40%); and mainly accumulated along the coastal belt and in southwest of the Cheju Island. Comparatively, the USMs were composed of fine biological fragments (10-70%), mineral particles (15-70%), and unrecognizable particles with various shapes (15-35%). They exhibited a clear heterogeneous distribution, namely, accumulated along the coastal belt and outer shelf, but dispersed in the mid-shelf, implying that USMs might be jointly controlled by biological activities, terrestrial inputs and hydrodynamic system in the ECS and the Yellow Sea. The distinct distribution difference between TSMs and USMs denotes their different exchange styles, i.e., for TSMs active in north of the ECS, and weak along the coastal front zone and 100 m isobath; while for USMs almost inactive along the coastal front zone, and active in the outer shelf. Our results may provide a novel clue for evaluating the contribution of TSMs to sedimentation, pollutant transfer and maintenance of marine biological communities with emphasis on the new method for collecting TSMs and USMs in the ECS.

Pollution levels of banned and non-banned pesticides in surface sediments from the East China Sea.

In this paper, 65 pesticides, including banned ones of DDTs, etc. and non-banned ones of iprobenfos, etc. have been detected in 31 surface sediment samples from the East China Sea (ECS) to study their pollution levels, sources, and risks. There were 8 banned pesticides (90-97%) and 10 non-banned pesticides (26-100%) presenting higher detection frequencies. For the 18 pesticides detected, their total contents ranged from 183.49 to 1363.77 ng/g dry weight (d.w.) and presented a seaward decreasing trend. Higher contents of banned pesticides were concentrated in the inner shelf close to Zhoushan Island. Iprobenfos, one of non-banned pesticides, showed the highest detection frequency (100%) and pollution level (79.14-1169.18 ng/g d.w.), indicating its continuous input in recent years. The pesticides concentrations in water calculated by the equilibrium partitioning (EqP) method were lower than the toxicological endpoint for tested aquatic invertebrates and fish, indicating ecological risks of these pesticides were at low levels.

Occurrence and origins of biomarker aliphatic hydrocarbons and their indications in surface sediments of the East China Sea.

The composition, distribution, indexes and budget of saturated lipid biomarker aliphatic hydrocarbons (AHs) in sediments of the East China Sea (ESC) were analyzed to identify their indications and sources. The resolved n-alkane (R) contents were 0.70-2.89 µg/g, with long-chain n-alkanes as the dominant composition in the ECS. The high R values mainly appeared at south inner shelf and north outer upwelling area, corresponding to the high mud, total organic carbon (TOC) and Chl a contents there. The composition, distribution pattern, combined with indexes of AHs, suggested no petroleum contamination and predominant biogenic sources in the ECS. The biogenic sources mainly were the mixed terrestrial higher plant, marine plankton and bacteria and aquatic macrophyte origins. Biotic source apportionment suggested that terrestrial higher plants were the dominant source of AHs, followed by marine planktons, with the lowest of submerged/floating macrophytes. Quantitative evaluation of R sources suggested that the Changjiang River input was the primary terrestrial contributor, accounting for 67.9% of total terrestrial input. The burial flux of R was 1.11 × 103 t/yr, with inner shelf and estuary as main accumulation areas. Although there was a huge amount of R influx from terrestrial and marine sources, only 9.8% could be preserved in sediments.