Contribution of Mountain River Materials to the Continental Shelf off Southeastern Hainan Island Since the Mid-Holocene

The concentrations of rare earth elements(REEs) in the bulk sediment of Core X2, which was collected from southeastern Hainan Island, were analyzed to investigate the relative contributions of various provenance regions since mid-Holocene. The results show that sediments in Core X2 were primarily derived from Hainan Island with lesser amounts from Taiwan and limited input from the Pearl River. Based on the application of quantitative inversion to model the REE data, the average contributions of river materials from southeastern Hainan Island and southwestern Taiwan to the study area were 68% and 32%, respectively. Furthermore, starting at 4.0 kyr BP, the transport of fluvial sediments from Taiwan to the study region increased due to enhanced hydrodynamics in South China Sea(SCS). These results indicate that the contributions of mountain river materials from Hainan Island and Taiwan to the continental shelf of northern SCS are non-negligible. Furthermore, these results demonstrate that mountain rivers can play an important role in the material cycle of continental margins and may feature a greater impact than large river systems in specific continental shelf areas.     

Provenance of Sediments Filling a Paleo-Channel that Formed on the Western Yellow Sea Continental Shelf During the Last Glacial Period

Several buried paleo-channels are located on the continental shelf of the western Yellow Sea. Research on the paleochannels is significant for both theoretical studies and practical applications. In this paper, we analyse and discuss the mineralogy of sediments in a core (SYS-0803) recovered from a buried paleo-channel on the continental shelf of the western Yellow Sea. The aim is to determine the provenance of sediments that fill the paleo-channel. The heavy mineral assemblage of sediments in the core consists of schistose minerals, common hornblende, epidote, and ilmenite. The light mineral assemblage consists of plagioclase, quartz, lithic fragments, and K-feldspar. Analysis of the compositional maturity of the sand fraction revealed a quartz/feldspar ratio of < 1. A relatively high percentage of smectite is recorded throughout the entire paleo-channel fill, with the greatest percentage in the middle to lower parts. The detrital mineral assemblage and clay mineral content indicate that the paleo-channel sediments were sourced mainly from the Huanghe River during the last glacial period.     

琼东海域锋面特征初探

2012年7月现场调查了海南岛东部陆架海(琼东海域),结合其中4个断面的实测数据和卫星遥感数据,探究该海域2012年海表温度锋面的季节性变化以及夏季锋面结构特征。研究表明,琼东海域温度锋面的季节性变化明显,强锋面中心会随季节变化。夏季锋面主要分布在上升流区,是典型的上升流锋面,锋带宽20~40 km,大致沿100 m等深线,随深度增加锋面强度减小,位置向外海移动。     

Heavy Minerals in Shelf Sediments off Fujian-Zhejiang Coast of the East China Sea: Their Provenance and Geological Application

To examine the composition and source variations of heavy minerals in the Fujian-Zhejiang mud belt(FZMB) over the past few hundred years, heavy minerals in 150 surficial sediment samples and two sediments cores collected from the southern FZMB were identified and analyzed. The results show that the mineral assemblage of hornblende-magnetite-epidote-chlorite is dominant in the study area. Based on the heavy mineral contents, the study area is divided into two mineral zones, namely a near-shore muddy sediment zone(zone Ⅰ) and an offshore mixed sediment zone(zone Ⅱ). The sediments from zone Ⅰ contains relatively abundant metallic minerals with proximal sediments from the Oujiang River and the Minjiang River as the primary component. The sediment from zone Ⅱ has relatively low content for minerals from the near-shore materials and is significantly affected by the Oujiang River sediments, and by the flaky minerals from the Yangtze River to a certain extent. The characteristics of heavy minerals in the cores may be affected by a variety of factors. Before the 20th century, under the influence of strong East Asian winter monsoon(EAWM), the sandy sediment in FZMB is significantly affected by the Oujiang River and the Yangtze River sediments, and relatively unaffected by near-shore terrigenous matter. In the 20th century, as the intensity of the Zhejiang-Fujian Coastal Current(ZFCC) decreased, the influence of the Minjiang coastal sand enhanced. Since the 1980s, as the collective effect of relatively weak EAWM and frequent storm surges and typhoons, the impact of the Minjiang River sediments on the FZMB sediments has increased considerably.     

夏季琼东陆架海急流锋面分析及其混合率参数化

基于2012年7月13日-20日夏季琼东海域的断面调查资料,研究了琼东急流锋面空间分布特征、混合过程及其参数化。结果表明,夏季琼东陆架海急流锋面主要分布在50 m~100 m等深线之间,且100 m等深线附近的锋面为强锋面区。强温盐锋面主要发生在25 m以浅,最大的强度锋面出现在14 m左右。锋区混合率的最大量级10~(-3)m~2·s~(-1),约比大洋平均值高2个量级,且高值主要分布在锋轴线附近和接近海表处。所提出的混合率参数化方案可以较好描述夏季琼东陆架海锋区混合的主要特征。     

Numerical simulation of the structure and variation of upwelling off the east coast of Hainan Island using QuikSCAT winds

The spatial structure and variation of the upwelling in the waters east and northeast of Hainan Island, China during 2000-2007 were investigated using a nested high-resolution Princeton Ocean Model (POM) forced by QuikSCAT winds. The model produced good simulations of the summer upwelling and the seasonal and annual variability. Strong upwelling occurs from mid-July to mid-August with a peak east of Hainan Island associated with the southwesterly monsoon in the South China Sea. Sensitivity experiments indicated that when the local wind stress controls the variability of the upwelling, the large-scale circulation significantly enhances the upwelling northeast of Hainan Island by inducing a local upwelling and transporting cold water northeast-ward along the island’s east coast. The joint effects of the local wind stress and large-scale circulation result in stronger upwelling northeast of Hainan Island. This implies that the annual variation of the upwelling northeast of Hainan Island is controlled not only by the local alongshore wind stress but also by the large-scale circulation. This result will help us investigate the decadal variation of the upwelling in this region in the future.     

台风“彩虹”对粤西近岸海表温度和叶绿素浓度的影响

利用高分辨率的海表面温度(SST)和叶绿素a浓度数据,分析2015年超强台风"彩虹"对粤西近岸海洋动力环境的影响。结果表明:"彩虹"过境后,粤西海域SST总变化为降温,且台风路径右侧降温高于左侧,最大热损失达到-9×10~6 J/m~3。"彩虹"引起的降温幅度以及最大降温出现时间在不同海区有所不同。珠江口附近海域、珠江口外海200 m等深线附近以及阳江至东海岛沿岸区域在台风登陆后2―4 d形成3个降温中心,最大降温均为-2℃左右。对台风路径两侧近岸、陆架和深水六个区域对比分析发现,近岸SST变化幅度最大,且两侧最大降温时间相同,而陆架和深水区则是左侧降温低于右侧。台风路径左侧雷州半岛以东约100 km和海南岛以东近海的叶绿素a浓度显著增加,最大增幅达5 mg/m~3。     

A NEW SPECIES OF RANINOIDES （CRUSTACEA ： DECAPODA ： RANINIDAE） FROM OFF THE SOUTHEASTERN COAST OF HAINAN ISLAND AND NANSHA ISLANDS

Ranlnoides longifions new species, off SE coast of Hainan Island, dorsal surface of carapace with an arched granular edge across carapace between the anterolateral teeth, median frontal tooth longest, second frontal teeth subquadrate.     

湛江港湾表层沉积物重金属的分布特征及潜在生态危害评价

利用双道原子荧光分析仪对湛江港附近海域表层沉积物砷、汞、铅、镉的含量进行了分析,阐明了这几种重金属的分布特征。结果表明,As的质量分数为(8.138~16.749)×10-6,平均12.745×10-6;Hg的质量分数为未检出(nd)~0.322×10-6,平均0.059×10-6;Pb的质量分数为(14.306~68.904)×10-6,平均44.258×10-6;Cd的质量分数为(1.561~6.882)×10-6,平均3.0874×10-6;砷、汞、铅从港内往港外有逐渐减少的趋势,镉的分布没有规律性,在整个港湾内的分布较均匀。从单因子污染指数看,砷、汞和铅都属生态危害轻微;镉污染较为严重,属生态危害强;从综合污染指数看,属生态危害中等。     

广东无居民海岛保护与利用政策研究

随着广东省海洋经济发展,其无居民海岛利用的深度和广度进一步加大,相关政策的作用开始凸显,但经济效益型无居民海岛无人问津、生态保护型与生态修复型无居民海岛遭严重破坏、海洋权益型无居民海岛亟需保护等问题严重。针对当前现状,政府今后的政策趋势应主要集中在三方面：一是明确产权管理,二是加强执法力度,三是实行分类管理。在制定无居民海岛发展政策时,要结合地方特点并不断探讨、制定与国家层面相配套的地方法规和政策措施,从而推动无居民海岛的可持续发展。     

Grain-Size Distribution of Surface Sediments in the Bohai Sea and the Northern Yellow Sea: Sediment Supply and Hydrodynamics

The grain-size distribution of surface sediments in the Bohai Sea (BS) and the northern Yellow Sea (NYS), and its relationship with sediment supply and hyd     

武汉市夏季城市热岛与不透水面增温强度时空分布

城市化的不断发展使自然地表不断被不透水面所取代,城市地表温度高于乡村,形成了显著的热岛效应。城市热岛给城市生态发展与人类健康带来了严重的负面影响,对其空间模式与背后形成机制的研究意义重大。本文以武汉市为例,基于2001、2007和2016年夏季Landsat系列影像使用辐射传导方程法反演了城市地表温度,并采用MOD11A1数据进行了验证;同时,计算了不同时期的城市温度等级和热岛比例指数,分析了城市热岛的时空变化。此外,为了探究热岛效应形成的主要原因,即不透水面与热环境的关系,全局角度使用多元线性回归分析对比了其增温效果与植被水体降温效果的强弱,空间局部角度采用地理加权回归结合地形数据得到了其增温强度的时空变化。结果表明：① 辐射传导方程法适用于实验中研究区的反演;武汉市城市热岛比例指数先增后减,但温度等级高的地区仍在不断扩张;② 多元线性回归可以准确地反映不同地表覆盖对地表温度的影响,R^2值为0.910,总体上武汉市不透水面的增温效果强于植被的降温效果,并弱于水体的降温效果; ③ 2001-2016年不透水面增温强度较高区域的分布呈现“单中心”到“多中心”的变化趋势,由单一集中于中心城区变为了分散集中于三环线附近的汉阳沌口工业区、青山工业区、阳逻开发区和东西湖区等地区。综上所述,武汉市夏季热环境问题仍然较为严重,城市外部地区的不透水面增温强度正在逐渐增大,规划治理应当给予这些地区更多的关注。     

Geochemical Characteristics of the Trace and Rare Earth Elements in Reef Carbonates from the Xisha Islands(South China Sea): Implications for Sediment Provenance and Paleoenvironment

Based on the concentrations of the trace elements, rare earth elements(REE), and Sr isotopic compositions in reef carbonates from the well ‘Xike-1' reef core of the Xisha Islands, the constraints on sediment provenance and paleoenvironment were defined. Variations of the terrigenous input into the paleoseawater were traced in detail and the paleoenvironment and sediment provenance were further investigated. The results show that the HREE/LREE values in the reef carbonates are negatively associated with their Th and Al concentrations; however, their Al and Th concentrations show positive correlation. The lowest 87 Sr/86 Sr values in the reef carbonates generally coincide with the lowest values of Al, Th concentrations and the highest values of HREE/LREE. These data indicate that the HREE/LREE, Al concentrations, and Th concentrations of the reef carbonates are useful indexes for evaluating the influence of the terrigenous inputs on the seawater composition in the study area. From top to bottom, the changing process of the HREE/LREE values and Al, Th concentrations can be divided into 6 intervals; they are H1(0–89.30 m, about 0–0.11 Myr), L1(89.30–198.30 m, about 0.11–2.2 Myr), H2(198.30–374.95 m, about 2.2–5.3 Myr), D(374.95–758.40 m, about 5.3–13.6 Myr), L2(758.40–976.86 m, about 13.6–15.5 Myr), and H3(976.86–1200.00 m, about 15.5–21.5 Myr). Moreover, the changing trend of the HREE/LREE values coincides with that of the seawater δ~(13)C values recorded by benthonic foraminiferal skeletons from the drill core of ODP site 1148 in the South China Sea(SCS), but not with that of the seawater δ~(18)O values. The high uplifting rates of the Qinghai-Tibet Plateau coincide with the high Th and Al concentrations and the low HREE/LREE values in the reef carbonates. These data indicate that the main factors controlling the changes of terrigenous flux in the SCS are the tectonic activities associated with Qinghai-Tibet Plateau uplifting and the variations of uplifting rates rather than paleoclimatic changes.     

Distribution and origin of sediments on the northern Sunda Shelf, South China Sea

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Organic Carbon in the Surface Sediments from the Intensive Mariculture Zone of Sanggou Bay: Distribution,Seasonal Variations and Sources

Mariculture has rapidly grown worldwide, which might greatly influence the biogeochemical cycle of organic carbon in coastal seas. In this study, several geochemical parameters, including grain size composition, sedimentary total organic carbon(TOC), total nitrogen(TN), stable carbon(δ13 C) and nitrogen(δ15 N) isotopic compositions, were analyzed for surface sediments collected from different mariculture zones of Sanggou Bay and in different seasons. We investigated the composition and distribution of organic matter in surface sediments and further evaluated the contribution of mariculture activities to TOC sources. The TOC and TN contents(mass percentage) in the bay were in the range of 0.14% to 1.45% and 0.03% to 0.20%, respectively. The spatial distribution indicated that sedimentary TOC and TN contents in shellfish monoculture and shellfish-kelp polyculture zones were higher than in other mariculture zones, which might be related to grain size composition and mariculture organisms. Seasonal variations of TOC contents were observed in different mariculture zones. The TOC/TN atomic ratio(C/N), δ13 C and δ15 N were in the ranges of 5.97 to 10.97,-21.76‰ to-13.14‰ and 2.13‰ to 8.08‰, respectively, implying that sedimentary organic matter in Sanggou Bay was the mixture of marine phytoplankton, terrestrial and maricultural sources. A simple mixing model based on δ13 C was applied and the results indicated that the relative contributions of organic carbon sources in Sanggou Bay followed the order kelp(36.6%) ? marine phytoplankton(28.7%) ? shellfish bio-deposition(23.8%) ? terrestrial input(10.9%). Surface sediments in Sanggou Bay were dominated by mariculture-derived organic carbon, which on average accounted for 60.4% of TOC.     

Distribution and Sources of Organic Matter in Surface Sediments of the Northern Bering and Chukchi Seas by Using Bulk and Tetraether Proxies

The organic matter (OM) preserved in Arctic Ocean sediments is of great importance to the global carbon budget. How-ever, works that apply multiple proxies to determine the distribution and concentration of organic carbon (OC) in the surface sedi-ments of the northern Bering and Chukchi Seas remain limited. Here a multiproxy approach based on bulk OM parameters and the branched vs. isoprenoid tetraether (BIT) index was used to investigate the distribution and sources of OM in the surface sediments of the northern Bering and Chukchi Seas. Binary and ternary mixing models were applied to trace the contribution of different OC sources to the total OC in the study area. The δ13C values of the sediments provided by the binary model showed that the proportion of terrestrial OC fell in the range of 27.4%–79.8% (46.2% on average). The BIT index returned the lowest fraction (4.8%–27.3%, 12.0% on average). The ternary mixing model was employed to determine the plant-, soil-, and marine-derived fractions of the total OM. The ternary model showed that 11.5%±6.3%, 31.4%±9.5%, and 57.1%±12.4% of OM in the sediment of the study area was derived from soil, plants, and marine sources, respectively. The differences in OM composition between the west and east sides of the Chukchi Sea were controlled by OM inputs from key water masses (i.e., Anadyr Water and Alaska Coastal Water), river discharge, and the nutrient supply from the Pacific inflow that supports marine productivity.     

Distribution Characteristics and Controlling Factors of Heavy Metals in Surface Sediments from the Bay-Island-Estuary System(BIES): A Case Study in Coastal Waters of Fujian Province,China

Based on the contents of six heavy metal elements in surface sediments from coastal areas of Fujian Province, the distribution characteristics and controlling factors of six heavy metals in a bay-island-estuary system(BIES) were studied. This paper focuses on the influence of the hydrodynamic environment, and systematically discusses how grain size compositions, chemical environment, tidal current, ocean circulation and human activities influence the distribution and transportation of the heavy ...     

大陆架划界的适用原则与方法论析——以中日东海大陆架划界为视角

大陆架划界一直存在"等距离划界"与"公平划界"之争,"等距离划界"规定在《大陆架公约》中,"公平划界"是《联合国海洋法公约》中有关大陆架划界的适用原则。基于国际法上条约效力的相对性,中日东海大陆架划界只能以公平划界原则作为划界的法律依据。在划界过程中,要正确区分划界的法律原则与划界方法的性质,将大陆架划界中涉及的自然延伸、公平划界、等距离划界分别纳入定义、法律原则和技术方法三个层面予以定性考察,从而揭示日本意欲将"等距离划界"方法上升至国际法层面的真实目的。     

西藏高原积雪覆盖空间分布及地形影响

利用2000-2014年MOD10A2积雪产品和数字高程模型DEM数据,以积雪覆盖率为指标,在分析西藏高原积雪空间分布特点的基础上,定量研究了高程、坡度和坡向等地形要素对高原积雪时空分布的影响。主要结论有：① 西藏高原积雪的空间分布差异显著,具有中东部念青唐古拉山和周边高山积雪丰富,覆盖率高,而南部河谷和羌塘高原中西部积雪少,覆盖率低的特点。② 海拔越高积雪覆盖率越高,积雪持续时间越长,年内变化越稳定。海拔2 km以下积雪覆盖率不足4%,海拔6 km以上覆盖率达75%。海拔4 km以下年内积雪覆盖呈单峰型分布特点,海拔越高,单峰型越明显;而海拔4 km以上则为双峰型,海拔越高,双峰型越明显。海拔6 km以下积雪覆盖率最低值出现在夏季,而6 km以上则出现在冬季。③ 总体上,高原地形坡度越高积雪覆盖率越高。不同坡向中,北坡积雪覆盖率最高,南坡最低,年内分布呈双峰型,而无坡向的平地积雪覆盖率要小于有坡向的山地,其年内变化呈单峰型分布特点。