陈敏
主要从事同位素海洋学方面的研究。
个性化签名
- 姓名:陈敏
- 目前身份:
- 担任导师情况:
- 学位:
-
学术头衔:
博士生导师
- 职称:-
-
学科领域:
海洋化学
- 研究兴趣:主要从事同位素海洋学方面的研究。
1970年4月生,教授、博士生导师,主要从事同位素海洋学方面的研究。1996年获厦门大学博士学位,先后在香港科技大学大气/沿岸海洋研究中心、美国阿拉斯加大学国际北极研究中心、香港科技大学生物系做访问研究。担任SCOR Working Group 116委员、中国海洋学会化学分会秘书长等职务。近年来,先后主持国家自然科学基金重点基金、“十五”科技攻关、中国北极科学考察专项基金等科研课题10余项。在Global Biogeochemical Cycles、Limnology and Oceanography、Marine Chemistry、Geophysical Research Letter、Deep-Sea Research、Journal of Environmental Radioactivity、Arctic、Sciences in China、Chinese Science Bullitin等国内外著名学术期刊上发表学术论文逾百篇。研究成果先后获得2003年国家海洋局海洋创新成果奖一等奖、2002年福建省科技进步二等奖、1997年中国科学院科技进步奖一等奖、福建省优秀博士学位论文三等奖等。承担3门课程的主讲任务,参与《海洋化学专门化实验》课程改革,该课程2005年被评为福建省省级精品课程,并获福建省高等教育教学成果奖二等奖。
主要研究兴趣如下:(1) 运用稳定同位素(13C、15N等)、成系天然放射性同位素(238U、234U、231Pa、234Th、232Th、230Th、228Th、210Pb、210Po)与宇生放射性同位素(33P、32P)研究海洋碳、氮、磷、铁等生源要素生物地球化学循环过程与速率。(2) 运用2H、18O、228Ra、226Ra、224Ra、223Ra、222Rn等同位素研究海洋水团组成、水体运动路径与速率。(3) 极地海洋学过程的同位素示踪,重点关注极地海域碳循环、水团组成与水体运动等方面的科学问题。(4) 铁、磷等营养元素存在形态及其生物可利用性的研究。
-
主页访问
3335
-
关注数
0
-
成果阅读
447
-
成果数
10
陈敏, Pinghe Cai a, Yipu Huang a, *, Min Chen a, Laodong Guo b, Guangshan Liu a, Yusheng Qiu a
Deep-Sea Research I 49(2002)53-66,-0001,():
-1年11月30日
228Ra, 228Th and 234Th in the upper 300m of the water column were measured to quantify new production and export flux of POC at the intercalibration station in the South China Sea during November 1997. Surprisingly high 228Ra concentrations of about 210dpmm-3 in the surface mixed layer were observed. The concentration decreased considerably, from >200dpmm-3 at 25m to ~43dpmm-3 at 200m, then increased to 87dpmm-3 at 300m close to the bottom (460m), coincident with the typical distribution pattern of 228Ra in open oceans. Concentrations of dissolved and particulate 228Th ranged from ~45 to ~27dpmm-3 and from ~40 to ~10dpmm-3, respectively, and showed a general decrease with increasing depth. A 234Th deficit relative to 238U was also observed in the upper 150m, as quantified by b-counting. The upward flux of nitrate into the euphotic zone was calculated by the coupled 228Ra-nitrate approach and further converted into a new production of 4.4mmol Cm-2 d-1 based on a Redfield ratio of 6.6 for C: N. The 234Th-238U disequilibrium and the measured ratio of POC to particulate 234Th yielded a POC export flux of 5.7mmol Cm-2 d-1, which is in general agreement with the new production derived from nutrient budgets. POC export based on the 228Th-228Ra disequilibrium was estimated to be 1.7mmol Cm-2 d-1, significantly lower than the derived new production. DOC transport or accumulation, data uncertainties and the different time scales to which the various methods were applied could be reasons for the discrepancy. The vertical fluxes of nitrate and phosphate to the euphotic zone bear a N/P molar ratio of 35, which is significantly higher than the Redfield ratio and suggests P-limitation in the southern South China Sea.
New production, Particle fluxes, Organic carbon, Radium, Thorium, Nutrient
-
44浏览
-
0点赞
-
0收藏
-
0分享
-
169下载
-
0评论
-
引用
【期刊论文】The effect of marine colloids on the growth of photosysthetic bacteria
陈敏, Airong Zheng*, Min Chen, Xuehong Zheng, Haiwei Shen, Lei Zhang
Marine Pollution Bulletin 45(2002)290-294,-0001,():
-1年11月30日
Marine colloids could be an important source of nitrogen for bacteria and photoplankton. But elevated concentration of colloids may stimulate algal growth and lead to red tides in coastal waters. The effects of colloidal organic carbon (COC) concentration on the growth of photosysthetic bacteria (PSB) were investigated under different colloidal treatments in the laboratory. The PSB growth was inversely proportional to COC concentration and was restricted by high-molecular-weight (HMW) colloids (>10KDa) in treatments with non-nutrient or just inorganic nutrient with low COC concentration (≤5μMC). However, the PBS growth was enhanced in the presence of HMW colloids in the treatment with inorganic nutrient and high COC (127 and 255μMC) or with both inorganic nutrient and low-molecular-weight organic matter. Both bacteria number and bacteria growth ratio increased significantly when the concentration of COC was ≥5μMC. Our results suggest that marine colloids can be utilized by bacteria and might regulate primary productivity in coastal waters.
-
36浏览
-
0点赞
-
0收藏
-
0分享
-
160下载
-
0评论
-
引用
陈敏, CHEN Min, HUANG Yipu, JIN Mingming, & QIU Yusheng
SCIENCE IN CHINA (Series D), 2003, 46 (6): 625~369,-0001,():
-1年11月30日
Seawater samples were collected in the water column from the Canada Basin aboard RV Xuelong in August 1999. Concentrations of d D, d 18O, nutrients (NO3-, PO43-, SiO32-) and dissolved oxygen were measured, along with hydrographic parameters (salinity and temperature). Our results showed that the upper layer of the water column was characterized by the occurrence of the upper halocline water (UHW) and the lower halocline water (LHW). The UHW was associated with a salinity of 33.1 (~150m depth) and maximums of nutrients, NO and PO*, whereas minimums of NO and PO* (PO*=PO3- + O2/175-1.95mmol/dm3) occurred at the depth of LHW (~300m depth). Two tracer systems, S-d 18O-PO* and S-d D-SiO3 2-, were used to estimate the fractions of the Atlantic water, Pacific water, river runoff and sea ice meltwater in water samples. Combined with the nutrient ratio NO/PO, it was suggested that the UHW was derived from the inflow of the Pacific water through the Bering Strait. These waters were modified to obtain the high salinity and nutrients in the Chukchi shelf or/and the east Siberian shelf. The LHW was maintained by inflow of the Atlantic water through Barents Sea and subsequent mixing with freshwater in the shelf region to produce the signals of NO and PO* minimums. In study basin, the river runoff signals were confined to water depths less than 300m and the fractions of river runoff decreased with the increasing depth. Water column inventories of river runoff and sea ice meltwater were calculated between the surface and 300m. The river runoff inventories in the Canada Basin were higher than those in other sea areas, suggesting that the Canada basin is a major storage region for Arctic river water. The sea ice meltwater signals suggested that the Canada Basin is a region of net sea ice formation and the inventories of net sea ice in the upper water column increasing from the south to the north.
halocline water,, water mass,, the Canada Basin,, 2H,, 18O,, nutrients.,
-
48浏览
-
0点赞
-
0收藏
-
0分享
-
200下载
-
0评论
-
引用
【期刊论文】Biological productivity and carbon cycling in the Arctic Ocean
陈敏, CHEN Min, HUANG Yipu, GUO Laodong, CAI Pinghe, YANG Weifeng, LIU Guangshan, & QIU Yusheng
Chinese Science Bulletin Vol. 47 No.12 June 2002,-0001,():
-1年11月30日
Primary production, bacterial production, particulate organic carbon fluxes and organic carbon burial rates were quantified during the summer period of 1999 in the Arctic Ocean via 14C uptake, 3H uptake, 234Th/238U disequilibrium and 210Pbex dating, respectively. The integrated primary production in the water column was as high as 197mmolC/(m2
Arctic Ocean,, primary production,, bacterial production,, POC export flux,, organic carbon burial rate,, isotopic tracer
-
52浏览
-
0点赞
-
0收藏
-
0分享
-
225下载
-
0评论
-
引用
陈敏, Lei Zhang, Min Chen, Weifeng Yang, Na Xing, Yanping Li, Yusheng Qiu, Yipu Huang
Journal of Environmental Radioactivity 78(2005)199-216,-0001,():
-1年11月30日
Thorium isotopes (228Th, 230Th, 232Th and 234Th) are useful tracers for studying particle dynamics and trace element scavenging in marine environments. In this study, surface waters were collected along a salinity gradient from the Jiulong River estuary, China, for determination of activity concentrations of 228Th, 230Th and 232Th in different size fractions, namely, the >53μm, 10-53μm, 2-10μm, 0.4-2μm, 10kDa-0.4mm and the <10kDa fractions. Our results indicated that the activity concentrations of 228Th, 230Th and 232Th in the Jiulong River estuarine waters were significantly higher than most of the previously reported values in coastal and oceanic seawaters, suggesting a higher lithogenic U and Th contribution from the Jiulong River Basin. When normalized to the particulate mass concentration, the activity concentrations of the three thorium isotopes decreased with increasing particle size, demonstrating the important role of surface areas of particles in controlling the scavenging of thorium from the water column. The partitioning of three thorium isotopes showed a common characteristic, i.e., the >53μm fraction had the least share (0-1%), while the 10-53μm fraction had the largest share of Th isotopes. The average value of the 230Th/232Th activity ratio (230Th/232Th) A.R. increased from 0.8 in the >53μm fraction to 3.7 in the 10kDa-0.4μm fraction, indicating that the radiogenic Th isotopes are preferentially scavenged by the small size particles. (230Th/232Th)A.R. in the <10kDa and 10kDa -0.4μm fractions were similar, however, suggesting a similar chemical composition and/or equilibrium partitioning between the low molecular weight and colloidal Th. It was very interesting to note that the geochemical behaviors of the three Th isotopes were different from each other. Dissolved 228Th had the highest concentration in the mid-salinity region, showing a non-conservative behavior with additional input. In contrast, dissolved 232Th showed a concave profile, indicating a net removal of 232Th during the mixing of fresh water with seawater. The behavior of Th isotopes in the 10kDa fraction followed those in the dissolved phases. The difference in geochemical behaviors among three Th isotopes was ascribed to their different sources in the estuary.
-
32浏览
-
0点赞
-
0收藏
-
0分享
-
182下载
-
0评论
-
引用
【期刊论文】Control of Pa/Th ratio by particulate chemical composition in the Ocean
陈敏, Laodong Guo, , Min Chen, and Celine Gueguen
GEOPHYSICAL RESEARCH LETTERS, VOL. 29, NO.0, XXXX,-0001,():
-1年11月30日
-
53浏览
-
0点赞
-
0收藏
-
0分享
-
59下载
-
0评论
-
引用
陈敏, MIN CHEN, , YIPU HUANG, PINGHE CAI, and LAODONG GUO
ARCTIC, VOL, 56 NO.1 (MARCH 2003) P. 32-44,-0001,():
-1年11月30日
Seawater samples were collected in the water column of the Canda Basin and the Bering Sea from aboard the R/B Xue Long during August 1999. Activity concentrations of dissolved and particulate 234Th were measured using beta countion techniques to quantify the scavenging and residence time of 234Th and organic carbon export fluxes. Prinary production (PP)and bacterial production were also determined in the study areas through in situ incubation experiments. Singificant 234Th scavenging was observed in the upper 100m of the water column in both study ares. with up to 40% of 234Th defictit found at Bering Sea stations and -15% of 234Th defictit at the Canada Basin station. Measured PP decreased from -12.5μmol C/m3/hin in surface water to near zero at -100m depth. with an integrated PP of 3.83mmol C/m2/d in the Canada Basin. Bacterial production. on the other hand. was on the order of 2.0mmol C/m2/d. which is up to 52% fo the integrated PP. Particulate organic carbon (POC) export fluxes derived from 234Th/238U disequilibrium were -1mmol C/m2/d in the Canda Basin and -10mmol C/m2/d in the Bering Sea. with fluxes in the latter areaheing 5 to 10 times higher than those found in the Caada Basin. These expon fluxes correspond to a ThE ratio (the ratio of 234Th-derived POC export to primary production) of 0.23 for the Canada Basin and 0.7 for the Bering Sea. The highe ThE rations in the study areas suggest a decoupling of production and particulate export in the high-latiude ocean. Rations fo POC to particlate 234Th (μmol C/dpm) decreased consistertly with incerasing depth, suggestion that organic carbon is preferentially remineralized relative to 234Th. Interestigly, The profile of particulate 234Th in the Canada Basin showed a unique characteristic: particulate 234Th activeites increased with increasing depth. suggesting a contiuous scavenging of 234Th and a rapid settling rate of the particles.
POC export flux., 234Th/, 218U disequilibrium., Primary production., Bacterial production,, the Canda Basin., The Bering Sea
-
63浏览
-
0点赞
-
0收藏
-
0分享
-
64下载
-
0评论
-
引用
【期刊论文】Marine diatom uptake of iron bound with natural colloids of different origins
陈敏, Min Chen a, , Robert C.H. Dei a, Wen-Xiong Wang a, *, Laodong Guo b
Marine Chemistry 81(2003)177-189,-0001,():
-1年11月30日
Natural colloids are abundant in seawater and are an intermediary in the fate, transport and bioavailability of many trace elements. Knowledge of the pathways and mechanisms of the biological uptake of colloidal Fe and other Fe species is of paramount importance in understanding Fe limitation on marine phytoplankton and thus carbon sequestration in the ocean. Whether the natural colloids serve as a source for the biological Fe requirements of marine phytoplankton, or just as a sink for particle-reactive metals in the oceans remains largely unknown. This study examined the bioavailability of Fe bound with colloids from different regions to a coastal diatom (Thalassiosira pseudonana). Natural colloids were isolated by cross-flow ultrafiltration and radiolabeled with 59Fe before being exposed to phytoplankton. Control experiments were conducted to ensure that 59Fe radiolabeled onto the colloids remained mostly in the colloidal phase. Both the natural oceanic and coastal colloidal organic matter complexed Fe (1nm-0.2Am) can be biologically available to the marine diatom even though its uptake was lower than the low molecular weight counterparts. By comparing the measured Fe internalization fluxes and the alculated maximum diffusive uptake fluxes, it is evident that ligand exchange kinetics on the cell surface may control the internalization of macromolecular Fe. The calculated concentration factors under dark and light conditions were generally comparable. Colloidal Fe, as an important intermediary phase, can be actively involved in the planktonic food web transfer through biological uptake and regeneration processes. The bioavailable fraction of Fe may be substantially underestimated by only considering the truly dissolved Fe or overestimated when using the external fluxes, such as aerosol Fe, as the bioavailable fraction.
Iron, Colloids, Bioavailability, Diatom, Uptake
-
38浏览
-
0点赞
-
0收藏
-
0分享
-
125下载
-
0评论
-
引用
陈敏, Min Chen, and Wen-Xiong Wang
Limnol. Oceanogr., 46(8), 2001, 1956-1967,-0001,():
-1年11月30日
Iron (Fe) is mostly complexed with the organic ligands or colloids that are very abundant in natural seawater. In this study, natural colloids were isolated by ultrafiltration and radiolabeled with 59Fe. The biological uptake of radiolabeled colloid-bound Fe of different sizes (1-10kDa and 10kDa-0.2mm) and ages (1 and 15d) by diatoms (Thalassiosira pseudonana) and copepods (Acartia spinicauda) was then determined. The uptake of radiolabeled colloid-bound Fe was compared with the uptake of low molecular weight (LMW) complexed Fe (1 kDa) or that of EDTA-Fe (at a ratio of 1:2 for Fe: EDTA). Our study demonstrates that the colloid-bound Fe of different sizes and ages was bioavailable to the diatoms. The uptake of colloidal bound Fe was, however, 6-31 times lower than the uptake of LMW Fe, suggesting that colloidal binding reduced Fe bioavailability to diatoms. Fe bound with small colloids (1-10kDa) was taken up at a higher rate than Fe bound with large colloids (10kDa-0.2mm) at typical colloidal organic carbon concentrations. The uptake of colloid-bound Fe was also much higher when the Fe had been bound with the colloids for 1d rather than for 15d. Differences in the colloidal organic carbon concentration did not appreciably affect the uptake of colloid-bound Fe by the diatoms. Similarly, copepods accumulated colloid-bound Fe at a much higher rate when the Fe was associated with small colloids rather than with large colloids. Direct ingestion of colloidal particles by the copepods appeared to be negligible. In both diatoms and copepods, Fe uptake may involve its dissociation from the colloids before being accumulated by the organisms. The study therefore demonstrates that colloid-bound Fe is less available for marine phytoplankton and that colloidal size and thus the colloidal speciation may be critical in controlling colloid-bound Fe uptake by aquatic organisms.
-
32浏览
-
0点赞
-
0收藏
-
0分享
-
124下载
-
0评论
-
引用
陈敏, Min Chen, and Wen-Xiong Wang, Laodong Guo
GLOBAL BIOGEOCHEMICAL CYCLES, VOL. 18,-0001,():
-1年11月30日
-
49浏览
-
0点赞
-
0收藏
-
0分享
-
94下载
-
0评论
-
引用