Arctic climate changes have profoundly influenced the polar environmental changes in recent years.The Arctic Oscillation(AO),as a key component of the Arctic climate system’s internal variability,affects the source t...Arctic climate changes have profoundly influenced the polar environmental changes in recent years.The Arctic Oscillation(AO),as a key component of the Arctic climate system’s internal variability,affects the source to sink processes and interactions across the multilayer Arctic system by regulating the land,ocean,sea ice,and atmospheric processes.The East Siberian Arctic Shelf(ESAS)has experienced significant changes in the input,transport,and burial of sedimentary organic carbon(OC)due to climate warming and shifts in the AO phase in recent decades.This study analyzes grain size,total organic carbon(TOC),total nitrogen(TN),and stable carbon isotope(δ^(13)C)in two sediment cores from the ESAS to reconstruct the burial record of OC over the past few decades and examine the response mechanism of sedimentary OC records to regional-scale climate forcing.The results show that the OC in the two sediment cores originates from mixed sources with a dominant terrestrial contribution.In the LV83-28 core from the Laptev Sea,the TOC and TN contents have increased at an accelerated rate since the 1990s,with a noticeable rise in the contribution of terrestrial OC.This trend is linked to an increase in terrigenous input caused by the positive AO phase.Core LV83-39 in the East Siberian Sea could have accumulated more terrestrial OC transported along the continental shelf during the positive AO.This implies that,under the interannual regulation of the AO regime,the input and crossshelf transport of terrigenous OC in the ESAS showed consistent sedimentary responses.This finding could enhance the understanding of the burial mechanism of sedimentary OC and its environmental response to regional climate change.展开更多
长江三角洲地区是我国重要的粮食生产基地,定量该地区主要稻作类型水稻生产的资源投入和碳氮足迹可为水稻种植结构调整和绿色低碳生产提供数据支撑。利用2016-2020年统计数据,运用生命周期评价方法,研究了长江三角洲地区的苏、浙、皖3...长江三角洲地区是我国重要的粮食生产基地,定量该地区主要稻作类型水稻生产的资源投入和碳氮足迹可为水稻种植结构调整和绿色低碳生产提供数据支撑。利用2016-2020年统计数据,运用生命周期评价方法,研究了长江三角洲地区的苏、浙、皖3省主要稻作类型水稻生产的资源投入和碳氮足迹。结果表明,粳稻氮肥用量最高,为279 kg/hm^(2),碳、氮足迹最高,分别为1.11 kg CO_(2)-eq/kg和13.7 kg N/t,产量较高。早籼稻氮肥用量最低,产量最低,分别为199 kg/hm^(2)和6371 kg/hm^(2),碳、氮足迹处于中间水平。中籼稻产量最高,为8687 kg/hm^(2),碳、氮足迹最低,分别为0.82 kg CO_(2)-eq/kg和10.3 kg N/t,氮肥用量处于中间水平。晚籼稻氮肥用量、产量及碳、氮足迹均处于中间水平。不同地区中江苏水稻氮肥用量最高,为309 kg/hm^(2),产量最高,为9319 kg/hm^(2),碳、氮足迹分别为0.948 kg CO_(2)-eq/kg和13.5 kg N/t。浙江水稻氮肥用量为216 kg/hm^(2),产量7364 kg/hm^(2),碳、氮足迹分别为0.989 kg CO_(2)-eq/kg和11.9 kg N/t。安徽水稻氮肥用量为204 kg/hm^(2),产量为7414 kg/hm^(2),碳、氮足迹分别为0.946 kg CO_(2)-eq/kg和11.1 kg N/t。由此可知,粳稻投入产出较高,碳氮足迹最高,存在较大的减排空间。中籼稻的投入较低,产量最高,碳氮足迹最低,是可推广的稻作类型。江苏水稻产量最高,投入最高,氮足迹最高,浙江和安徽水稻投入产出差异较小,碳氮足迹差异较小。展开更多
Particulate organic carbon (POC) and its isotopic composition were measured monthly in the ChangjiangRiver (at Sta. Datong)for a whole year. It shows that their seasonal distribution has an obvious change and is simil...Particulate organic carbon (POC) and its isotopic composition were measured monthly in the ChangjiangRiver (at Sta. Datong)for a whole year. It shows that their seasonal distribution has an obvious change and is similarto that of the Huanghe River. The annual weighted mean of POC 13 C values of the Changjiang River is almost the same as that of the Huanghe River. Based on the data of runoff and sediment load measured daily and POC concentra-tion measured monthly the POC flux at Sta. Datong was estimated. The flux value at Datong may be considered ap-proximately to be the M flux of the Changjiang River discharging into the sea. The M flux of the Changjiang Riv-er is slightly larger than that of the Huanghe River.展开更多
The atmospheric precipitation plays an important role in influencing the river chemistry of the Dongjiang River. The atmospheric contribution to river water is estimated by reference to Cl concentration called Cl r...The atmospheric precipitation plays an important role in influencing the river chemistry of the Dongjiang River. The atmospheric contribution to river water is estimated by reference to Cl concentration called Cl ref . The Cl ref of 41 97 μmol/L represents the highest chloride concentration of the rainwater inputs to river water, thus sea salts are responsible for total Cl concentration of the Dongjiang River. According to the principal compositions of precipitation and river water, two approaches sea salt correction and precipitation correction were proposed in order to correct the contribution proportions of atmospheric precipitation on the solutes and to calculate chemical weathering rate. The results reflected that the atmospheric contribution ratios fluctuate from ～5% to ～20% of TDS(total dissolved solids) in the Dongjiang River. As compared with the other world watersheds, the lower dissolved ion contents and high runoff may result in the obvious influence of precipitation on river chemistry in the Dongjiang basin. The major elemental chemistry is mainly controlled by silicate weathering, with the anion HCO - 3 and cation Ca 2+ and Na\++ dominating the major compositions in this basin. The estimated chemical weathering rate of 15 78—23 48 t/(km 2·a) is only 40%—60% of a global average in the Dongjiang basin. Certainly, the estimated results are still under correction gradually because the effect of human activities on the precipitation chemistry has never been quantified in detail.展开更多
Novel tetracyclic terpanes X and Y namely C24-des-A-oleanane and C27 tetracyclic terpane were detected in crude oils and source rock extracts in Zhu 1 depression in Pearl River Mouth Basin by GC-MS analysis technology...Novel tetracyclic terpanes X and Y namely C24-des-A-oleanane and C27 tetracyclic terpane were detected in crude oils and source rock extracts in Zhu 1 depression in Pearl River Mouth Basin by GC-MS analysis technology. These compounds are similar to oleanane in the structure, and their relative abundance in m/z 191 partial mass cbromatogram has a good correlation with oleanane. Here compounds X and Y are considered to be derived from the des-A degradation of oleanoid precursor. The ratio of X/（X-I-C24） and Y/（Y-I-C24） increase with the increasing inputs of terrigenous organic matter in crude oils. Wenchang Formation middle-deep lacustrine source rocks with planktonic algae organic matter inputs and oil generating from it contain low abundance of compounds X and Y, while Enping Formation coal measures source rocks with terrigenous higher plants organic matter inputs and oil generating from it usually have higher compounds X and Y. In general when two terrigenous compounds C19 tricyclic terpane and bicadinane-T are high in crude oils, there are also a corresponding high abundant compounds X and Y. Relative abundance of compounds X and Y is closely related to the source of organic matter and it can indicate the input of terrigenous organic matter.展开更多
基金The National Natural Science Foundation of China under contract Nos 42130412 and 42376068the Fundamental Research Funds for the Central Universities under contract No.202241001+2 种基金the Ocean Negative Carbon Emissions Program and the Taishan Scholar Program under contract No.TSQN20182117the Russian Scientific Foundation under contract No.21-77-30001the Ministry of Science and Higher Education of the Russian Federation under contract Nos 124022100083-1 and 124022100084-8.
文摘Arctic climate changes have profoundly influenced the polar environmental changes in recent years.The Arctic Oscillation(AO),as a key component of the Arctic climate system’s internal variability,affects the source to sink processes and interactions across the multilayer Arctic system by regulating the land,ocean,sea ice,and atmospheric processes.The East Siberian Arctic Shelf(ESAS)has experienced significant changes in the input,transport,and burial of sedimentary organic carbon(OC)due to climate warming and shifts in the AO phase in recent decades.This study analyzes grain size,total organic carbon(TOC),total nitrogen(TN),and stable carbon isotope(δ^(13)C)in two sediment cores from the ESAS to reconstruct the burial record of OC over the past few decades and examine the response mechanism of sedimentary OC records to regional-scale climate forcing.The results show that the OC in the two sediment cores originates from mixed sources with a dominant terrestrial contribution.In the LV83-28 core from the Laptev Sea,the TOC and TN contents have increased at an accelerated rate since the 1990s,with a noticeable rise in the contribution of terrestrial OC.This trend is linked to an increase in terrigenous input caused by the positive AO phase.Core LV83-39 in the East Siberian Sea could have accumulated more terrestrial OC transported along the continental shelf during the positive AO.This implies that,under the interannual regulation of the AO regime,the input and crossshelf transport of terrigenous OC in the ESAS showed consistent sedimentary responses.This finding could enhance the understanding of the burial mechanism of sedimentary OC and its environmental response to regional climate change.
文摘长江三角洲地区是我国重要的粮食生产基地,定量该地区主要稻作类型水稻生产的资源投入和碳氮足迹可为水稻种植结构调整和绿色低碳生产提供数据支撑。利用2016-2020年统计数据,运用生命周期评价方法,研究了长江三角洲地区的苏、浙、皖3省主要稻作类型水稻生产的资源投入和碳氮足迹。结果表明,粳稻氮肥用量最高,为279 kg/hm^(2),碳、氮足迹最高,分别为1.11 kg CO_(2)-eq/kg和13.7 kg N/t,产量较高。早籼稻氮肥用量最低,产量最低,分别为199 kg/hm^(2)和6371 kg/hm^(2),碳、氮足迹处于中间水平。中籼稻产量最高,为8687 kg/hm^(2),碳、氮足迹最低,分别为0.82 kg CO_(2)-eq/kg和10.3 kg N/t,氮肥用量处于中间水平。晚籼稻氮肥用量、产量及碳、氮足迹均处于中间水平。不同地区中江苏水稻氮肥用量最高,为309 kg/hm^(2),产量最高,为9319 kg/hm^(2),碳、氮足迹分别为0.948 kg CO_(2)-eq/kg和13.5 kg N/t。浙江水稻氮肥用量为216 kg/hm^(2),产量7364 kg/hm^(2),碳、氮足迹分别为0.989 kg CO_(2)-eq/kg和11.9 kg N/t。安徽水稻氮肥用量为204 kg/hm^(2),产量为7414 kg/hm^(2),碳、氮足迹分别为0.946 kg CO_(2)-eq/kg和11.1 kg N/t。由此可知,粳稻投入产出较高,碳氮足迹最高,存在较大的减排空间。中籼稻的投入较低,产量最高,碳氮足迹最低,是可推广的稻作类型。江苏水稻产量最高,投入最高,氮足迹最高,浙江和安徽水稻投入产出差异较小,碳氮足迹差异较小。
文摘Particulate organic carbon (POC) and its isotopic composition were measured monthly in the ChangjiangRiver (at Sta. Datong)for a whole year. It shows that their seasonal distribution has an obvious change and is similarto that of the Huanghe River. The annual weighted mean of POC 13 C values of the Changjiang River is almost the same as that of the Huanghe River. Based on the data of runoff and sediment load measured daily and POC concentra-tion measured monthly the POC flux at Sta. Datong was estimated. The flux value at Datong may be considered ap-proximately to be the M flux of the Changjiang River discharging into the sea. The M flux of the Changjiang Riv-er is slightly larger than that of the Huanghe River.
文摘The atmospheric precipitation plays an important role in influencing the river chemistry of the Dongjiang River. The atmospheric contribution to river water is estimated by reference to Cl concentration called Cl ref . The Cl ref of 41 97 μmol/L represents the highest chloride concentration of the rainwater inputs to river water, thus sea salts are responsible for total Cl concentration of the Dongjiang River. According to the principal compositions of precipitation and river water, two approaches sea salt correction and precipitation correction were proposed in order to correct the contribution proportions of atmospheric precipitation on the solutes and to calculate chemical weathering rate. The results reflected that the atmospheric contribution ratios fluctuate from ～5% to ～20% of TDS(total dissolved solids) in the Dongjiang River. As compared with the other world watersheds, the lower dissolved ion contents and high runoff may result in the obvious influence of precipitation on river chemistry in the Dongjiang basin. The major elemental chemistry is mainly controlled by silicate weathering, with the anion HCO - 3 and cation Ca 2+ and Na\++ dominating the major compositions in this basin. The estimated chemical weathering rate of 15 78—23 48 t/(km 2·a) is only 40%—60% of a global average in the Dongjiang basin. Certainly, the estimated results are still under correction gradually because the effect of human activities on the precipitation chemistry has never been quantified in detail.
文摘Novel tetracyclic terpanes X and Y namely C24-des-A-oleanane and C27 tetracyclic terpane were detected in crude oils and source rock extracts in Zhu 1 depression in Pearl River Mouth Basin by GC-MS analysis technology. These compounds are similar to oleanane in the structure, and their relative abundance in m/z 191 partial mass cbromatogram has a good correlation with oleanane. Here compounds X and Y are considered to be derived from the des-A degradation of oleanoid precursor. The ratio of X/（X-I-C24） and Y/（Y-I-C24） increase with the increasing inputs of terrigenous organic matter in crude oils. Wenchang Formation middle-deep lacustrine source rocks with planktonic algae organic matter inputs and oil generating from it contain low abundance of compounds X and Y, while Enping Formation coal measures source rocks with terrigenous higher plants organic matter inputs and oil generating from it usually have higher compounds X and Y. In general when two terrigenous compounds C19 tricyclic terpane and bicadinane-T are high in crude oils, there are also a corresponding high abundant compounds X and Y. Relative abundance of compounds X and Y is closely related to the source of organic matter and it can indicate the input of terrigenous organic matter.
