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1.
Huang  Yuhuan  Sun  Chengjun  Yang  Guipeng  Yue  Xin&#;an  Jiang  Fenghua  Cao  Wei  Yin  Xiaofei  Guo  Chaonan  Niu  Jiaohong  Ding  Haibing 《中国海洋湖沼学报》2020,38(3):650-664
Journal of Oceanology and Limnology - Two sediment cores were retrieved in the hadal zone of the Yap Trench, and their concentrations of six major elements Mg, Al, Ca, Ti, Mn and Fe and nine trace...  相似文献   

2.
Niu  Jiaohong  Sun  Chengjun  Yang  Bo  Xie  Lei  Jiang  Fenghua  Cao  Wei  Chen  Yan  Ding  Haibing  Huang  Yuhuan  Gao  Xianchi 《中国海洋湖沼学报》2023,41(1):118-137

The composition and concentration of dissolved free amino acid (DFAA) of seawater samples collected in May 2016 from the surface to the hadal zone of the northern region of the Yap Trench were analyzed by pre-column derivatization of o-phthalaldehyde. Results show that the average concentration of DFAA in the study area was 0.47±0.36 µmol/L. In different sampling stations, the concentrations of DFAA with water depth showed complex variation patterns. At the sediment-seawater interface, the concentrations of DFAA in the western side of the trench were obviously higher than that in its eastern side. In the study area, there were no significant correlations between the concentrations of DFAA and the environmental parameters such as concentrations of chlorophyll a (Chl a), dissolved oxygen (DO), pH, and dissolved inorganic nitrogen (DIN), indicating that the concentrations of DFAA in seawater of the trench are affected by many factors, such as photosynthesis, respiration, temperature, pressure, illumination, and circulation. The dominant DFAA are similar in different water layers of sampling stations, including aspartic acid (Asp), glutamic acid (Glu), glycine (Gly), and serine (Ser). The composition of different amino acids, and the relative abundance of acidic, basic, and neutral amino acids might be related to the sources and consumption of various amino acids. Nine pairs of amino acids in the DFAA showed significantly positive relationship by correlation matrix analysis, suggesting that they might share similar biogeochemical processes. The degradation index (DI) of the DFAA in seawater of the Yap Trench could reflect the degradation, source, and freshness of DFAA in the trench to some extents. This is a preliminary study of amino acids from sea surface to hadal zone in the ocean, more works shall be done in different trenches to reveal their biogeochemical characteristics in extreme marine environments.

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3.
Using observations in an applied cruise of the submersible Jiaolong, water characteristics, geostrophic transport, and turbulent mixing in abyssal and hadal zones of the southern Yap Trench were studied. The spatial structures of deep water show that the abyssal water is cold, saline, and oxygen rich. The hadal water has very small changes in potential temperature and potential density, and a little decrease in salinity and obvious decrease in oxygen. The isotherm, isopycnal, and isohaline are depressed in abyss over the central trench. The turbulent mixing is enhanced in the near-bottom zone and the hadal water on the trench slope, especially at the steep slope, the dissipation rate and diffusivity is strong, which weakens the stratification. The geostrophic flows move southward in the western region of the trench and northward in the eastern region, indicating cyclonic circulation. In the central region of the trench, the water transport is ~1.74 Sv southward. In the hadal zone, the northward and southward transports are balanced. Our analysis suggests that the abyssal water in the southern Yap Trench is from Lower Circumpolar Water (LCPW) and the hadal water seems to be of the isolated local water rather than LCPW.  相似文献   

4.
In order to explore the standing stock and preservation of organic carbon, different forms of compound specific lipids were analyzed, based on a 1.8 m sediment core collected in the northern continental shelf of South China Sea in May, 2016. In the core sediments, 21 species of fatty acids, 6 species of alcohols, 8 species of sterols and phytol were detected. Fatty acids were dominated components with the percent of 67%–91% in the total lipids, in which saturated fatty acid C16:0 accounted for about 50%. The contents of lipid species generally decreased from the sediments at surface to those deep, except alcohols waving in a certain range at the same time. Fatty acids primarily existed in free form, followed by base hydrolytic form, and then acid hydrolytic form. Free alcohols were obviously dominated, while base and acid hydrolytic forms contributed small comparably. Phytol gave a significant priority to base hydrolytic form, while acid hydrolytic form could be neglected. Similar to phytol, sterols mostly presented in base hydrolytic form, and then in free form. The compositions of lipids and their forms suggested that organic carbon basically originated from primary production in upper waters in studying area, and were well preserved in the sediments.  相似文献   

5.
A series of laboratory incubation experiments were conducted to examine the decomposition of algal organic matter in clay-enriched marine sediment under oxic and anoxic conditions. During the 245-day incubation period, changes in the concentrations of TOC, major algal fatty acid components (14:0, 16:0, 16:1, 18:1 and 20:5), and n-alkanes (C16–C23) were quantified in the samples. Our results indicate that the organic matters were degraded more rapidly in oxic than anoxic conditions. Adsorption of fatty acids onto clay minerals was a rapid and reversible process. Using a simple G model, we calculated the decomposition rate constants for TOC, n-alkanes and fatty acids which ranged from 0.017–0.024 d−1, 0.049–0.103 d−1 and 0.011 to 0.069 d−1, respectively. Algal organic matter degraded in two stages characterized by a fast and a slow degradation processes. The addition of clay minerals montmorillonite and kaolinite to the sediments showed significant influence affecting the decomposition processes of algal TOC and fatty acids by adsorption and incorporation of the compounds with clay particles. Adsorption/association of fatty acids by clay minerals was rapid but appeared to be a slow reversible process. In addition to the sediment redox and clay influence, the structure of the compounds also played important roles in affecting their degradation dynamic in sediments.  相似文献   

6.
Jiang  Zuzhou  Sun  Zhilei  Liu  Zhaoqing  Cao  Hong  Geng  Wei  Xu  Haixia  Wang  Lisheng  Wang  Libo 《中国海洋湖沼学报》2019,37(3):998-1009
The hadal zone represents one of the last great frontiers in modern marine science, and deciphering the provenance of sediment that is supplied to these trench settings remains a largely unanswered question. Here, we examine the mineralogical and geochemical composition of a sediment core(core CD-1) that was recovered from the southwestern margin of the Challenger Deep within the Mariana Trench. Major element abundances and rare-earth element patterns from these sediments require inputs from both terrigenous dust and locally sourced volcanic debris. We exploit a two-endmember mixing model to demonstrate that locally sourced volcanic material dominates the sediment supply to the Challenger Deep(averaging ～72%). The remainder, however, is supplied by aeolian dust(averaging ～28%), which is consistent with adjacent studies that utilized Sr-Nd isotopic data. Building on a growing database, we strengthen our understanding of Asian aeolian dust input into the northwestern Pacific, which ultimately improves our appreciation of sedimentation in, and around, the hadal zone.  相似文献   

7.
Li  Yingjie  Cao  Wenrui  Wang  Yan  Ma  Qingjun 《中国海洋湖沼学报》2019,37(3):1024-1029
Microbial diversity in the abyssal sediments beneath the seafloor of 30, 94, and 151 cm near the southern end of the Mariana Trench was analyzed in the Illumina HiSeq 2500 platform. Results show that the microbial populations were dominated by bacteria but merely no archaea were identified at the three depths. In the bacterial community,Proteobacteria and Firmicutes dominated the total taxon tags, followed by Bacteroidetes, Actinobacteria, Planctomycetes, Cyanobacteria, and Chloroflexi, which together account for over 99% of the total population. Similar to that in the seawater in the trench, the operational taxonomic units(OTUs) belonging to Gammaproteobacteria from the sediment samples showed high abundance.However, common bacterial OTUs in the water of the trench including Nitrospirae and Marinimicrobia were hardly found in the sediments from the southern Mariana Trench or the hadal region. Therefore, this study documented for the first time the compositions of microbial diversity in the trench sediments, revealed the difference in microbial diversity in water and sediment of the trench and will enrich the knowledge on the microbial diversity in the abyssal areas.  相似文献   

8.
Based on a new idea for research on cycling of marine biogenic elements, this study showed that only the leachable form phosphorus in natural grain sizes manne sediments constitutes the transferable phosphorous in the sediments. The transferable phosphorus content in the natural grain sizes surface sediments in the Huanghe River estuary adjacent waters ranges from 58.5-69.8 μg/g, accounting for only 9.1%-11.0% of the total phosphorus content, whereas the leachable form (“transferable” )phosphorus content in the sediment after it was totally ground into powder was found to be 454.8-529.2μg/g, accounting for 73.4%-89.1% of the total phosphorus. Analysis of the correlation between thebill,ass of benthos and the leachable form (“transferable” ) phosphorus showed that most of the leachableform (“transferable”) phosphorus in the totally ground sediment did not participate in the marine biogeo chemical cycling. Furthermore, a synchronous survey on benthos showed that the biornass of meio-and maero-benthos exhibited good positive correlation with the leachable form of phosphorus in the naturalgrain sizes sediment, but peorer correlation with the leachable form (“transferable”) phosphorus in the totally ground sediment, indicating that transferable phosphorus in marine sediment is the leachable form of phosphorus in the natural grain sizes sediments, and is not the previously known leachable form(“transferable”) phosphorus obtained from the totally ground sediment.  相似文献   

9.
This study was conducted to compare lipid and fatty acid composition of cod, haddock and halibut. Three groups of cod (276 g ± 61 g), haddock (538 g ± 83 g) and halibut (3704 g ± 221 g) were maintained with commercial feeds mainly based on fish meal and marine fish oil for 12 weeks prior to sampling. The fatty acid compositions of muscle and liver were determined by GC/FID after derivatization of extracted lipids into fatty acid methyl esters (FAME). Lipids were also fractionated into neutral and polar lipids using Waters silica Sep-Pak?. The phospholipid fraction was further separated by high-performance thin-layer chromatography (HPTLC) and the FAME profile was obtained. Results of the present study showed that cod and haddock were lean fish and their total muscle lipid contents were 0.8% and 0.7%, respectively, with phospholipid constituting 83.6% and 87.5% of the total muscle lipid, respectively. Halibut was a medium-fat fish and its muscle lipid content was 8%, with 84% of the total muscle lipid being neutral lipid. Total liver lipid contents of cod, haddock and halibut were 36.9%, 67.2% and 30.7%, respectively, of which the neutral lipids accounted for the major fraction (88.1%–97.1%). Polyunsaturated fatty acids were the most abundant in cod and haddock muscle neutral lipid. Monounsaturated fatty acid level was the highest in halibut muscle neutral lipid. Fatty acid compositions of phospholipid were relatively constant. In summary, the liver of cod and haddock as lean fish was the main lipid reserve organ, and structural phospholipid is the major lipid form in flesh. However, as a medium-fat fish, halibut stored lipid in both their liver and muscle.  相似文献   

10.
Trimethylamine N-oxide(TMAO) is one of the most important nutrients for bacteria in the deep-sea environment and is capable of improving pressure tolerance of certain bacterial strains.To assess the impact of TMAO on marine microorganisms,especially those dwelling in the deep-sea environment,we analyzed the bacterial community structure of deep-sea sediments after incubated under different conditions.Enrichments at 50 MPa and 0.1 MPa revealed that TMAO imposed a greater influence on bacterial diversity and community composition at atmospheric pressure condition than that under high hydrostatic pressure(HHP).We found that pressure was the primary factor that determines the bacterial community.Meanwhile,in total,238 bacterial strains were isolated from the enrichments,including 112 strains a ffiliated to 16 genera of 4 phyla from the Yap Trench and 126 strains a ffiliated to 11 genera of 2 phyla from the Mariana Trench.Treatment of HHP reduced both abundance and diversity of isolates,while the presence of TMAO mainly af fected the diversity of isolates obtained.In addition,certain genera were isolated only when TMAO was supplemented.Taken together,we demonstrated that pressure primarily defines the bacterial community and culturable bacterial isolates.Furthermore,we showed for the first time that TMAO had distinct influences on bacterial community depending on the pressure condition.The results enriched the understanding of the significance of TMAO in bacterial adaptation to the deep-sea environment.  相似文献   

11.
This study was conducted to compare lipid and fatty acid composition of cod,haddock and halibut.Three groups of cod(276 g±61 g),haddock(538 g±83 g)and halibut(3704 g±221 g)were maintained with commercial feeds mainly based on fish meal and marine fish oil for 12 weeks prior to sampling.The fatty acid compositions of muscle and liver were determined by GC/FID after derivatization of extracted lipids into fatty acid methyl esters(FAME).Lipids were also fractionated into neutral and polar lipids using Waters silica Sep-Pak(R).The phospholipid fraction was further separated by high-performance thin-layer chromatography(HPTLC)and the FAME profile was obtained.Results of the present study showed that cod and haddock were lean fish and their total muscle lipid contents were 0.8% and 0.7%,respectively,with phospholipid constituting 83.6% and 87.5% of the total muscle lipid,respectively.Halibut was a medium-fat fish and its muscle lipid content was 8%,with 84% of the total muscle lipid being neutral lipid.Total liver lipid contents of cod,haddock and halibut were 36.9%,67.2% and 30.7%,respectively,of which the neutral lipids accounted for the major fraction(88.1%-97.1%).Polyunsaturated fatty acids were the most abundant in cod and haddock muscle neutral lipid.Monounsaturated fatty acid level was the highest in halibut muscle neutral lipid.Fatty acid compositions of phospholipid were relatively constant.In summary,the liver of cod and haddock as lean fish was the main lipid reserve organ,and structural phospholipid is the major lipid form in flesh.However,as a medium-fat fish,halibut stored lipid in both their liver and muscle.  相似文献   

12.
The carbohydrate and lipid contents in two planktonic crustaceans, i. e.Pseudeuphausia sinica andAcetes chinensis sampled from Xiamen coastal waters were estimated. InP. sinica, the contents of carbohydrates (in dry weight) and lipids varied from 2.19–2.33% and 21.2–21.9% respectively; inA. chinensis from 1.74–2.55% and 14.43–15.10% respectively. The analyses of fatty acids by gas-chromatograph (Model 103) showed that eight fatty acids of 14∶0, 15∶0, 16∶0, 17∶0, 18∶0, 18∶2, 20∶2 and 22∶2 were found in these two animals, that 16∶0, 18∶0, 18∶2, and 20∶2 formed the major constituents with 91.08% (P. sinica) and 74.80% (A. chinensis) of the total fatty acids, and that the values of odd carbon types (15∶0 and 17∶0) were fairly low, 4.47% and 3.36% respectively. Three monosaccharides: glucose, fructose, and galactose detected by high-liquid chromatograph (Waters 208) accounted for more than 60% of the total carbohydrates, especially the glucose, exceeding by 40%.  相似文献   

13.
Total lipid and fatty acid composition of eight strains of marine diatoms   总被引：3，自引：0，他引：3  
Fatty acid composition and total lipid content of 8 strains of marine diatoms (Nitzschia frustrula, Nitzschia closterium, Nitzschia incerta, Navicula pelliculosa, Phaeodactylum tricornutum, Synedra fragilaroides) were examined. The microalgae were grown under defined conditions and harvested at the late exponential phase. The major fatty acids in most strains were 14∶0 (1.0%–6.3%), 16∶0 (13.5–26.4%), 16∶1n−7 (21.1%–46.3%) and 20∶5n−3 (6.5%–19.5%). The polyunsaturated fatty acids 16∶2n−4, 16∶3n−4, 16∶4n−1 and 20∶4n−6 also comprised a significant proportion of the total fatty acids in some strains. The characteristic fatty acid composition of diatoms is readily distinguishable from those of other microalgal groups. Significant concentration of the polyunsaturated fatty acid 20∶5n−3 (eicosapentaenoic acid) was present in each strain, with the highest proportion in B222 (19.5%). Project supported by the Hi-Tech “863” Programs of the China Ministry of Science and Technology (863-819-02-01).  相似文献   

14.
The molecular biomarker compositions of the ornithogenic sediments (YN), from Svalbard, Arctic were investigated. The results showed that n-alkanes had a bimodal pattern and their odd-even preference was not obvious. The alkanes contained unresolved complex mixtures (UCM) and relatively high levels of pristine and retene, indicating pollution from the nearby coal mines. The n-alkanols in the sediments had even-to-odd preference, and they might originate mainly from modern biota. Sistosterol, the main sterol in herbivores feces, was the dominant sterol, indicating that sitosterol might be a good biomarker of input from the birds feces in the sediments. The fatty acids of the sediments showed acid. The α-hydroxyl acids and ω-hydroxyl fatty acids were also detected in the sediments. In summary, the organic matters in the YN sediments were from the adjacent coal mines, bird feces, and plants.  相似文献   

15.
From March 2004 to February 2005,seasonal variations in lipid content and fatty acid composition of gonad of the cockle Fulvia mutica(Reeve) were studied on the eastern coast of China in relation to the reproductive cycle and environment conditions(e.g.,temperature and food availability).Histological analysis as well as lipid and fatty acid analyses were performed on neutral and polar lipids of the gonad.Results showed that gametogenesis occurred in winter and spring at the expense of lipids previously accumulated in summer and autumn,whereas spawning occurred in summer(20.4-24.6℃).The seasonal variation in lipid content was similar to that of the mean oocyte diameter.In both neutral and polar lipids,the 20:5n-3 and 22:6n-3 levels were relatively higher than saturated fatty acids,and polyunsaturated fatty acids were abundant,with series n-3 as the predominant component.Seasonal variations in the 20:5n-3 and 22:6n-3 levels and the principal n-3 fatty acids were clearly related to the reproductive cycle.The ∑(n-3) and ∑(n-6) values were relatively high during January-May,and the associated unsaturation index was significantly higher than that in other months.The results suggest that fatty acids play an important role in the gametogenesis of F.mutica.  相似文献   

16.
A series of laboratory incubation experiments were conducted to examine the decomposition of algal organic matter in clay-enriched marine sediment under oxic and anoxic conditions.During the 245-day incubation period,changes in the concentrations of TOC,major algal fatty acid components (14:0,16:0,16:1,18:1 and 20:5),and n-alkanes (C16-C23) were quantified in the samples.Our results indicate that the organic matters were degraded more rapidly in oxic than anoxic conditions.Adsorption of fatty acids onto cla...  相似文献   

17.
Lipids were extracted from organs of the starfish Asterias amurensis associated with different treatments(raw-control,boiling and heating),and then analyzed for lipid content,lipid oxidation index,lipid classes and fatty acid composition.Results showed that boiling softened the hard starfish shells,thus facilitating the collection of starfish organs.As compared with raw organs,the boiled organs had lower water content and higher lipid content,possibly due to the loss of water-holding capacity caused by protein denaturation.Both boiling and heating increased the peroxide value(PV),thiobarbituric acid(TBA) value and carbon value(CV) of lipids.Despite slight increases in the content of complex lipids,associated lipid composition had no substantial variations upon boiling and heating.For simple lipids,the content of 1,2-diglyceride decreased in boiled and heated organs,with free fatty acids observed on thin layer chromatography(TLC).However,neither boiling nor heating significantly changed the fatty acid compositions of simple or complex lipids in starfish organs,suggesting that these two treatments had no significant effects on complex lipids in starfish organs.Together,our results indicated that boiling of starfish soon after capture facilitated the handling and extraction of useful complex lipids consisting of abundant glucosylceramide and eicosapentaenoic acid(EPA)-bounded phospholipids.  相似文献   

18.
Over-summering is a crucial period for Calanus sinicus in the southern Yellow Sea,where it is a key member of the zooplankton community.Lipids play an important role in copepod diapause,which is part of their over-summering strategy.We investigated how different fatty acids and lipid classes,including wax esters,changed during over-summering of C.sinicus during three cruises in June and August 2011 and November 2010,corresponding to the pre-,during and post-diapause periods,respectively.Large amounts of lipids were accumulated,mainly wax esters as previously found in C.finmarchicus during its diapause,and most of the storage lipids were used during over-summering.Wax ester polyunsaturated fatty acids(PUFAs) showed the most variation of the fatty acids(FAs),while the percentage composition of FAs in polar lipids was relatively stable.Selective use of wax ester PUFAs has already been shown to play important roles in the winter diapause of Calanus species in other regions,and our FA results show that this is the case for the Yellow Sea Cold Bottom Water(YSCBW) population that diapauses in summer.  相似文献   

19.
Anammox (anaerobic ammonium oxidation) is an important process in many suboxic to anoxic marine environments for converting fixed nitrogen to N2, and has a major impact on the marine nitrogen cycle. Ladderane core lipids have been utilized as an indicator of the contribution of anammox to the marine nitrogen cycles. However, such studies have not been reported for the China seas and little is known about the importance of anammox within the nitrogen cycle of these marginal seas. In the research reported here, the ladderane core lipid contents of 17 surface sediment samples from the East China Sea are reported, and their spatial distribution is investigated. C18 -[5]-ladderane FAME, C20-[5]-ladderane FAME and C20-[3]-ladderane FAME have all been detected, suggesting that the anammox bacteria are widely present within the study area. The total contents of the three ladderane lipids (ΣFAMEs) range from 24–355 ng/g (weight of dry sediments), with higher contents occurring in the Minzhe Mud Zone and broadly coincident with the spatial distribution of hypoxia. It is suggested that the sedimentary ladderane core lipids are mainly produced in the water column and their sedimentary contents can be used as indicators of water column hypoxia.  相似文献   

20.
The composition and compound-specific isotopes of fatty acids were studied within food webs in the East China Sea.Lipid-normalized stable carbon isotopes of total organic carbon had a good correlation with trophic level.Variations in fatty acid compositions among different species were observed but were unclear.Different dietary structures could be traced from molecular isotopes of selected fatty acids in the Shiba shrimp(Matapenaeus joyneri),the coastal mud shrimp(Solenocera crassicomis) and the northern Maoxia shrimp(Acetes chinensis).Both M.joyneri and S.crassicomis are mainly benthos feeders,while A.chinensis is a pelagic species,although they have a similar fatty acid composition.There was a good correlation for isotopes of arachidonic acid(C20:4n6;ARA) and docosahexaenoic acid(C22:6n3;DHA)among pelagic species from higher trophic levels.The isotopic compositions of DHA in benthic species were more negative than those of pelagic species at the same trophic level.The fact that the diet of benthic species contains more degraded items,the carbon isotopes of which are derived from a large biochemical fraction,may be the reason for this variation.A comparative study of benthic and pelagic species demonstrated the different carbon sources in potential food items and the presence of a more complex system at the watersediment interface.  相似文献   

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