•River input contributes little to long chain alkyl diols in study sites.•LDI proxy may reflect annual mean SST in the study area.•Diol index 2 can indicate Yuedong Upwelling intensity in the past ...decades.
Long chain alkyl diols in sediment cores were studied in the Yuedong Upwelling (YDU) area in the coastal northern South China Sea to investigate whether sea surface temperature (SST) and upwelling intensity over the last few decades can be traced by the diol-derived indices, i.e., the LDI (long chain diol index) as a proxy for SST and the DI-1 and DI-2 (diol index 1 and 2) as proxies for upwelling intensity. The influence of riverine long chain alkyl diols (e.g., 1,13- and 1,15-diols), which may affect LDI-reconstructed SSTs, was largely ruled out based on the comparison between diol distributions in suspended particulate materials in the Pearl River estuary and the core sediments. LDI-derived SSTs in downcore sediments matched well with local annual mean SSTs. The records of DI-2 changed in parallel with the local wind stress and inversely with SST at times of upwelling, suggesting that DI-2 is an effective proxy for upwelling intensity of YDU. The DI-1 showed a generally inverse variation pattern with DI-2, implying a major influence by SST, and it is thus not an applicable upwelling indicator for YDU. A negative relationship of DI-1 and a positive relationship of DI-2 with LDI-derived SST were observed. This occurrence might be attributed to El Niño–Southern Oscillation (ENSO), because the SST and upwelling intensity were largely modulated by ENSO, showing a warm annual mean SST during the years of enhanced El Niño and intensified summer upwelling.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The Shin-Yan-Ny-Hu (SYNH) MVs are typical subaerial mud volcanoes in southwestern Taiwan. The lipid biomarkers and their stable carbon isotopes were firstly examined to delineate the mud breccia ...sources, depositional environments, thermal maturity, probable source strata and the migration framework of volcanic fluid. The sediment organic matter within active SYNH MVs principally stemmed from the petroleum derivatives, bacteria and terrigenous C3 plants suggested by the following indicators: the CPI of n-alkanes (∼1); the distribution and δ13C values of saturate, fatty acids and the plot of Pr/n-C17 vs. Ph/n-C18 ratios. The Pr/Ph ratios, the plot of Pr/n-C17 vs. Ph/n-C18 and the plot of Pr/Ph vs. O/C30 Hopane ratios implied that the sediment organic matter was deposited in a marine deltaic sedimentary environment under an oxic depositional environment. The C30 βα/C30 αβ, Tmax, 22 S/(22 S + 22 R) ratios of homohopane (C31) and bishomohopane (C32), MPI1, MPI2, F1, F2, Tmax vs. HI and the Pr/n-C17 vs. Ph/n-C18 ratios revealed that the Type III organic material was early thermal maturity and the burial depth of mud breccia matrix was estimated around 4–5 km bsf.
•The organic matter of SYNH MVs was derived from petroleum derivatives, bacteria and terrestrial higher plants.•The mud breccia matrix was deposited in a marine deltaic environment under an oxidized sedimentary environment.•The source organic matter was early thermal maturity, and the burial depth of mud breccia matrix was about 4–5 km bsf
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The surface sediments collected from the southern Mariana Trench at water depths between ca. 4900 m and 7068 m were studied using lipid biomarker analyses to reveal the origin and distribution of ...organic matters. For all samples, an unresolved complex mixture (UCM) was present in the hydrocarbon fractions, wherein resistant component tricyclic terpanes were detected but C27–C29 regular steranes and hopanes indicative of a higher molecular weight range of petroleum were almost absent. This biomarker distribution patterns suggested that the UCM and tricyclic terpanes may be introduced by contamination of diesel fuels or shipping activities and oil seepage elsewhere. The well-developed faults and strike-slip faults in the Mariana subduction zone may serve as passages for the petroleum hydrocarbons. In addition, the relative high contents of even n-alkanes and low Carbon Preference Indices indicated that the n-alkanes were mainly derived from bacteria or algae. For GDGTs, the predominance of GDGT-0 and crenarchaeol, together with low GDGT-0/Crenarchaeol ratios (ranging from 0.86 to 1.64), suggests that the GDGTs in samples from the southern Mariana Trench were mainly derived from planktic Thaumarchaeota. However, the high GDGT-0/crenarchaeol ratio (10.5) in sample BC07 suggests that the GDGTs probably were introduced by methanogens in a more anoxic environment. Furthermore, the n-alkanes C19–C22 and the n-fatty acids C20:0–C22:0 were depleted in 13C by 3‰ compared to n-alkanes C16–C18 and the n-fatty acids C14:0–C18:0, respectively, which was interpreted to result from the preferential reaction of fatty acid fragments with carbon “lighter” terminal carboxyl groups during carbon chain elongation from the precursors to products. The abundance of total alkanes, carboxylic acids, alcohols and total lipids were generally increased along the down-going seaward plate, suggesting the lateral organic matter inputs play an important role in organic matter accumulation in hadal trenches. The extremely high contents of biomarkers in sample BC11 were most likely related to trench topography and current dynamics, since the lower steepness caused by graben texture and proximity to the trench axis may result in higher sedimentation rate. This paper, for the first time, showed the biomarker patterns in surface sediments of the Mariana Trench and shed light on biogeochemistry of the hardly reached trench environment.
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•The even-carbon alkanes were mainly synthesized by bacteria or algae.•The C12–C22 fatty acids and the dominated n-C18 alcohol was from algae and bacteria.•The GDGTs were derived from planktic Thaumarchaeota and methanogens, respectively.•The δ13C offsets between C16–C18 and C20–C22 were caused by carbon chain elongation.•The contents of total and specific classes with water depth is generally increased.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Long-chain
n
-alkanols and
n
-alkanes in core sediments from the northern South China Sea (SCS) were measured to make a comparison during terrestrial vegetation reconstruction from ~42 ka to ~7 ka. ...The results showed that terrestrial vegetation record from long-chain
n
-alkanes matched well with previous studies in nearby cores, showing that more C
4
plants developed during the Last Glacial Maximum (LGM) and C
3
plants dominated in the interglacial period. However, these scenarios were not revealed by terrestrial vegetation reconstruction using long-chain
n
-alkanols, which showed C
3
plant expansion during the LGM. The discrepancy during the interglacial period could be attributed to the aerobic degradation of functionalized long-chain
n
-alkanols in the oxygen-rich bottom water, resulting in poor preservation of terrestrial vegetation signals. On the other hand, the different advantages of functionalized
n
-alkanols and non-functional
n
-alkanes to record local and distal vegetation signals, respectively, may offer a potential explanation for the contradiction during the LGM when the SCS was characterized by low-oxygen deep water. Nevertheless, large variations on
n
-alkyl lipid compositions in C
3
/C
4
plants could play a part in modulating sedimentary long-chain
n
-alkanols and
n
-alkanes toward different vegetation signals, thereby suggesting that caution must be taken in respect to the terrestrial vegetation reconstruction using long-chain n-alkanes and long-chain
n
-alkanols.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The clinical applicability of porcine xenotransplantation-a long-investigated alternative to the scarce availability of human organs for patients with organ failure-is limited by molecular ...incompatibilities between the immune systems of pigs and humans as well as by the risk of transmitting porcine endogenous retroviruses (PERVs). We recently showed the production of pigs with genomically inactivated PERVs. Here, using a combination of CRISPR-Cas9 and transposon technologies, we show that pigs with all PERVs inactivated can also be genetically engineered to eliminate three xenoantigens and to express nine human transgenes that enhance the pigs' immunological compatibility and blood-coagulation compatibility with humans. The engineered pigs exhibit normal physiology, fertility and germline transmission of the 13 genes and 42 alleles edited. Using in vitro assays, we show that cells from the engineered pigs are resistant to human humoral rejection, cell-mediated damage and pathogenesis associated with dysregulated coagulation. The extensive genome engineering of pigs for greater compatibility with the human immune system may eventually enable safe and effective porcine xenotransplantation.
One gravity core retrieved from the Niger Delta was used to explore the origin of deposited organic matter (OM) and the paleo-climatic and environmental conditions over the Holocene in equatorial ...West Africa. The geochemical properties of sediments including glycerol dialkyl glycerol tetraethers (GDGTs) and elemental (%OC, %N, C/N) and isotopic (δ13Corg, δ15N) signatures were determined. The determination constrained the age of the column and revealed that the sediment OM was mainly derived from a marine source. The isoprenoid (iso)GDGTs were the dominant GDGTs, with a small amount of branched (br)GDGTs, which led to a low-branched and isoprenoid tetraether index (BIT, 0.02–0.21) and represented a low terrestrial input. Most isoGDGTs and OH-GDGTs were produced in situ by Marine Group I (MG-I) Thaumarchaeota, while the brGDGTs were mainly transported from land. A two-endmember model quantified the contribution of terrestrial OM, as 0.9–19.9% by BIT and 1.1–32.6% by δ13C. Accordingly, the millennium-scale sea surface temperatures (SSTs) were reconstructed based on the cyclopentane ring distribution (TEX86H) and the ring index of OH-GDGTs (RI-OH). The top core SSTs were lower than the modern mean annual SST due to the growth season and habitat depth of Thaumarchaeota. The reconstructed SSTs clearly revealed the four stages of paleoclimate change, in particular, the drought episode of 8.2 kyr and the following humid period. The above research has enhanced our understanding of the paleoclimate change in river outflow during the Holocene at the millennium scale.
Authigenic carbonates were recovered from several locations of the South China Sea continental slope at a 470m to 770m water depth. The sources of seeping fluids, the time involved in carbonate ...formation and the potential driving forces are increasingly understood, but little is known about the biogeochemical processes that occur during this type of carbonate precipitation. Here, a molecular and isotopic investigation of authigenic carbonates was conducted to determine the factors controlling the types of microbial consortia in cold-seep environments. The studied carbonates were one aragonitic crust and three high-Mg calcitic tubular concretions from specific sites. A significant input of biogenic methane to the carbon pool during the precipitation of the carbonates was suggested by the presence of 13C-depleted molecular fossils of methanotrophic archaea (with δ13C values as negative at −141.5‰) and sulfate-reducing bacteria (with δ13C values as negative at −128.5‰). The methane was primarily oxidized in an anaerobic process. The predominant consortia were ANME-2 assemblages in the aragonitic carbonate (sample TVG3-C2), whereas high-Mg calcitic carbonates (samples TVG14-C2 and TVG8-C5) were dominated by ANME-1 assemblages according to the specific biomarkers observed. Taking the favored environments for specific AOM consortia and crystallization conditions for aragonite and calcite together, the factors selecting for specific AOM communities appear to be constrained by their biogeochemical settings. Accordingly, higher alkalinity, abundant sulfate concentration and being closer to the water–sediment interface conditions favor the precipitation of aragonite over high-Mg calcite.
•13C-depleted molecular fossils of methanotrophic archaea and sulfate-reducing bacteria were found.•AOM with distinctive lipid biomarkers that point to different archaeal assemblages.•Varying microbial consortia confirmed in samples appear to be caused by respective biogeochemical settings.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Authigenic carbonates were recovered from the northern Okinawa Trough at 540–700 m water depth. Development of microbial communities and seepage dynamics driving the precipitation of authigenic ...carbonates remains poorly constrained, even though the source of methane-rich fluids, formation of Fe-rich carbonates, and the potential driving forces were previously reported. Here, petrologic observations, stable carbon and oxygen isotopic compositions, mineralogy, and lipid inventories of authigenic carbonates from the northern Okinawa Trough were analyzed. The carbonate minerals were comprised predominantly of aragonite, high-magnesium calcite, and siderite. The presence of molecular fossils diagnostic for anaerobic methane oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB) with pronounced 13C depletions (as low as −134‰), together with highly negative δ13Ccarb values (as low as −55.8‰), suggest that the carbonates precipitated from anaerobic oxidation of methane (AOM) with microbial methane as the predominant carbon source. The difference between measured and calculated δ18Ocarb values (based on 0‰ of sea water δ18O vs V-SMOW) was higher than +3‰ in one of the carbonates (GGD16), reflecting an origin from gas hydrate dissociation. Most of the carbonates revealed δ18O offsets between measured and calculated values within +3‰, or a lower measured δ18O than calculated value, suggesting a mixture of methane-derived carbonates (low δ13C/high δ18O) and detrital origin carbonates (high δ13C/low δ18O). Biomarker patterns varied significantly among samples. A suite of 13C-depleted biomarkers indicated the predominance of an ANME-1 assemblage for all samples, suggesting carbonates formed at low to medium methane flux. The predominance of ANME-1, abundant detrital minerals, and allochthonous biomarkers, as well as low carbonate contents indicate that most samples formed at greater depth within the sediment column. Only one carbonate sample in this study is interpreted to have precipitated at relatively shallower depth, as indicated by the occurrence of crocetane, dominance of aragonite, and higher overall carbonate content.
•Lipid biomarker patterns of the Okinawa Trough carbonates were studied.•Carbonates formed from low to medium methane flux as revealed by lipids of ANME-1.•Most carbonates formed at greater depth within the sediment column.•One carbonate is interpreted to have precipitated at relatively shallower depth.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Phospholipid ester-linked fatty acids (PLFA) were used to investigate the microbial ecology and its association with carbon accumulation in one soil profile from the Dinghushan Biosphere Preserve in ...south China, in order to probe the mechanisms that control the carbon accumulation at the depth of 0 - 20 cm in the Dinghushan forest soil profile. The data show that sulfate reducing bacteria (SRB) occur in the top 10 cm, and methanotrophic bacteria and fungi are not present below 10 cm, and the gramnegative bacteria are reduced with gram-positive bacteria dominating at that depth; all of which indicated that the activities of some of the microorganisms were inhibited, from which we infer that the available carbon source and oxygen content of micro environment may be reduced below 10 cm of the profile. The shallow depth (top 10 cm) of the soil anaerobic zone at the Wukesong profile, compared to the normal soil anaerobic zone (top 20 - 30 cm), is considered to be mainly the result of the high precipitation of acidic rain. The physicochemical reactions caused by acid rain in the soil system result in a decreased soil porosity, and a correspondingly decreased porosity-dependent oxygen concentration, leading to the thriving of SRB in the shallow depth. Although the increase of soil organic carbon stock is attributed to numerous factors, the decreasing rate of litter decomposition in the topsoil layer, together with the rise of the depth of the anaerobic zone, may play key roles in the carbon accumulation in the depth of 0 - 20 cm in the soil profile from the Dinghushan Biosphere Preserve.
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FFLJ, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UL, UM, UPUK
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