末次冰期南海巽他陆架上的植被和气候——17962孔孢粉记录

提供了南海大陆坡上17962孔深海沉积物的孢粉记录.该孔长8 m,底部14C年龄为30 000 a BP,跨越了深海氧同位素3期、末次冰期、冰消期和全新世几个地质历史阶段.孢粉记录显示末次冰期低海面时南海南部出露的陆架上覆盖了低地雨林.同时,在邻近的岛屿上山地雨林扩张,表明气候比现在凉,但是没有变干的迹象.冰消期植被和气候都经历了快速变暖和变凉的波动.全新世时,红树林和低地雨林的扩张以及孢粉沉积率的明显降低均表明气候变暖,海面上升,大陆架被淹没.     

末次冰盛期低海面时南海南北陆架上的植被

在探讨孢粉的传播、来源地的基础上,根据南海南北陆坡柱状剖面（１７９４０ ,１７９６４） 的孢粉资料推断末次冰盛期（包括氧同位素３ 期的上部） 低海面时,南北出露的大陆架上生长的植被。末次冰盛期时北部大陆架曾分布以蒿属（Ａｒｔｅｍｉｓｉａ Ｌ．） 为主的草原植被,气候较今日冷且干旱。南部称为“巽他古陆”,曾覆盖热带低地雨林,河口及海岸为红树林,在周围岛屿上高山雨林曾多次向山下迁移,表明当时温度可能较今日低,但湿度没有明显变化。南北大陆架末次冰期时在植被与气候演化上的巨大差异,可能与南部巽他陆架的特殊位置（ 西太平洋暖池） 有关     

末次冰消期以来南海北部表层海水盐度变化

对南海北部MD05-2904孔上部0-398cm段共152个样品的硅藻鉴定结果进行主成分分析.根据主成分分析结果,探讨了末次冰消期以来南海北部表层海水盐度(SSS)变化历史,并分析其变化的主要原因.末次冰消期以来南海北部表层海水盐度呈阶段性变化,与季风降水强度变化趋势基本一致,表明季风降水强度变化可能是南海北部表层海水盐度变化的主要影响因素;珠江冲淡水是南海北部表层海水盐度变化另一个比较重要的影响因素,但其影响程度在全新世中晚期有所减弱.末次冰消期南海北部表层海水盐度变化硅藻记录还明显反映了新仙女木(Younger Dryas)这一短期气候事件,事件发生期间南海北部表层海水盐度明显上升,主要与当时季风降水明显减少有关.MD05-2904孔硅藻盐度记录基本可以与17940孔有孔虫盐度记录相对比,但也存在一定差异,尤其在全新世中晚期,主要与两者代表不同盐度含义有关,后者代表由局地淡水收支变化引起的盐度变化,而前者代表所有影响因素综合作用下的盐度变化.     

四万年来南海北部周边地区植被演替序列—孢粉生物群区化方法恢复古植被的尝试

就南海北部海域17940孔的孢粉资料,利用孢粉生物群区化方法和因子分析方法,对南海北部周边地区4万年以来的植被演替序列进行研究。结果表明：对于深海沉积物,在排除远距离搬运的花粉尤其是松属（Pinus L.)花粉的噪音后,可以利用孢粉生物群区化方法恢复周边大陆古植被演替序列。因子分析表明,湿度和温度的变化是影响南海北部周边大陆植被演化的主要因子。在40500－11100aBP南海北部沿海大陆地区的古植被,主要为常绿阔叶林（WAMF）,山地针叶林（MRGF）分布于低山、丘陵、而广泛出露的大陆架上则发育了以蒿属(Artemisia L.)为主的草原（STEP）景观：末次冰期时环境变化的突出特征山地针叶林（MRGF）、常绿阔叶林（WAMF）与草原（STEP）之间的频繁交替,反映了气候冷湿和温干的千年级尺度的迅速变化,可以与Heinrich事件以及Dansggard-Oscherge事件进行对比。其中在7.0m处（12700aBP)所恢复的山地针叶林（MRGF）景观反映了一次气候变冷变湿的事件,可能与新仙女木事件相对应。全新世早期和末期较多出现热带雨林（TRFO0以及热带季雨林（TSFO）景观,而全新世中期以常绿阔叶林（WAMF）为主,缺乏热带雨林（TRFO）以及热带季雨林（TSFO）景观,可能表明在全新世中期尽管温度升高,但湿度有可能降低。     

陇中黄土高原末次冰盛期以来的植被演替及其气候响应

末次冰盛期以来,地球系统经历了一次从冷到暖完整的气候旋回,是过去全球变化研究的一个重要时段。本文基于陇中黄土高原会宁硝沟剖面河湖相-水下黄土沉积序列的高分辨率地层孢粉记录,探讨该区末次冰盛期以来的植被演替及其气候响应模式,旨在为黄土高原生态环境建设的战略部署提供科学依据,且对进一步探讨区域气候演化机制、预测未来气候环境变化趋势具有重要意义。硝沟剖面的孢粉记录揭示,末次冰盛期以来该区的植被演替过程为:荒漠草原(寒冷的盛冰期)→针叶疏林/森林草原(逐渐增温的冰消期)→针阔叶混交林为主的森林草原→针阔叶混交林(温暖的盛间冰期)→针叶疏林草原→干草原/荒漠草原;相应的气候变化模式为:冷干→较温湿→较暖湿→暖湿→温凉偏干→较冷干。总体来看,末次冰盛期以来,研究区植被对气候环境变化的响应非常敏感,随着气候的冷暖干湿变化,森林/疏林草原带自东南-西北发生多次进退;区域顶极植物群落为中全新世气候最适宜期发育的针阔叶混交林,研究区早中全新世较长时期都有较大面积的针阔叶混交林发育;晚全新世植被退化为干草原/荒漠草原,一方面可能是气候持续变干的自然响应,另一方面可能也与此时强烈的人类活动对自然森林/草原植被的破坏导致的恶性循环有关。     

末次冰期以来湛江湖光岩玛珥湖孢粉记录及古环境变化

通过对湛江湖光岩玛珥湖钻孔孢粉记录的研究认为,末次冰期以来,该区植被类型从早期的南亚热带季风常绿阔叶林依次演替为,中亚热带常绿、落叶阔叶林→南亚热带季风常绿阔叶林→中亚热带常绿—落叶阔叶—针叶混交林(湖边草地)→热带季雨林→半常绿季雨林。气候最寒冷的时期温度比目前至少降低了4—6℃以上。全新世早期相对于旱。     

长江三角洲锦溪地区全新世气候适宜期孢粉组合及其环境意义北大核心CSCD

通过对长江三角洲锦溪地区白莲湖附近人工剖面的孢粉研究,重建该地区7 230cal a BP前后的植被和气候。孢粉植物群反映当时气候略有波动,但整体上与全新世气候适宜期的温暖环境相一致。孢粉自下而上可以细分为4个组合带:Zone 1青冈栎含量丰富,反映温暖气候;Zone 2落叶栎有所增多,气候稍有转凉;Zone 3青冈栎含量再度增高,气候变暖;Zone 4松属和落叶栎明显增多,气候再度转凉。从沟鞭藻和相关孢粉类型的分布分析,除底部12号样品因孢粉含量低而未予考虑外,其它样品都指示沉积时期当地受到海水的影响。其中Zone 1和Zone 2孢粉植物群指示两次海水的进退过程。当前孢粉研究结果很好地反映出长江三角洲地区全新世大暖期的气候变化特征,以及与当时海平面变化的关联。     

长江三角洲锦溪地区全新世气候适宜期孢粉组合及其环境意义

通过对长江三角洲锦溪地区白莲湖附近人工剖面的孢粉研究,重建该地区7 230cal a BP前后的植被和气候。孢粉植物群反映当时气候略有波动,但整体上与全新世气候适宜期的温暖环境相一致。孢粉自下而上可以细分为4个组合带:Zone 1青冈栎含量丰富,反映温暖气候;Zone 2落叶栎有所增多,气候稍有转凉;Zone 3青冈栎含量再度增高,气候变暖;Zone 4松属和落叶栎明显增多,气候再度转凉。从沟鞭藻和相关孢粉类型的分布分析,除底部12号样品因孢粉含量低而未予考虑外,其它样品都指示沉积时期当地受到海水的影响。其中Zone 1和Zone 2孢粉植物群指示两次海水的进退过程。当前孢粉研究结果很好地反映出长江三角洲地区全新世大暖期的气候变化特征,以及与当时海平面变化的关联。     

末次冰期以来中国海区浮游有孔虫Pulleniatina obliquiloculata含量变化的地层学意义

西北太平洋尤其是中国海区末次冰期旋回中浮游有孔虫Pulleniatina obliquiloculata含量变化研究是近年来最重要的古海洋学内容之一.作者综合分析了中国及邻近海区具有可靠测年地层的深海沉积物柱状样中P.obliquiloculata含量变化,探讨其含量低值事件(PME)的生物地层学意义.末次冰期以来P.obliquiloculata含量变化在中国海区呈现两种变化模式:一是以东海及南海北部为代表的冰期含量低、间冰期含量高的特点;另一种则是南海南部的冰期含量高、间冰期含量低的现象.高分辨率地层记录显示,在这种冰期/间冰期总体变化趋势基础上,我国东海、南海和黑潮源区等广泛存在晚全新世～4 300-2 800 cal yr BP P.obliquiloculata含量低值,但以南海北部与东海冲绳海槽最为明显;而南海南部P.obliquiloculata含量还在冰消期(～16.5-15 cal kyr BP)有另一特征的低含量阶段.因而,末次冰期旋回中国海区P.obliquiloculata含量变化可以作为区域性地层划分和对比的标志.尽管如此,由于黑潮分支水团的影响,冲绳海槽中部和北部部分海域,在末次冰期与PME期间,P.obliquiloculata虽然含量相对较低,但仍可保持3%-5%以上,而非多数站位PME事件中的特征性零含量.研究表明PME事件主要由次表层海水的温度降低、温跃层变浅、上部水体温度梯度增加等引起,与表层海水无关,但引起这些海洋环境变化的原因尚不清楚.     

南岭东部新仙女木事件的孢粉学证据

冰消期至早全新世的仙女木事件（Ｙｏｕｎｇｅｒ Ｄｒｙａｓ,简称ＹＤ）,因降时间短,气候波动强,是全球气候研究者关注的热点。根据近期的研究,ＹＤ事件上在欧洲、北美和我国北方都有所表现。但在我国长江以南的内陆地区,未见报道。笔者在用孢粉资料探讨我国南方南岭东部地区１５０００ｙｒ ＢＰ以来的植被与环境演变时,发现约在１０４００ｙｒ ＢＰ前,植被发生了较大的变化,气候有一较明显的降温被动,这是我国低纬度人     

The vegetation and climate at the last glaciation on the emerged continental shelf of the South China Sea

Studies on the dispersal mechanism and source areas of pollen from hemipelagic sediments recovered from the continental slopes of the South China Sea (SCS) reveal that vegetation existed on the exposed shelves at the Last Glacial Maximum (LGM) and the latter part of the Marine Isotope Stage 3. At the low sea level stand, Artemisia-dominated grassland covered the northern continental shelf and tropical lowland rainforest and mangroves grew on the southern shelf ‘Sunda Land’. Consequently, the climate in the northern SCS must have been much colder and drier during the last glacial period compared to the present. Sunda Land experienced only a marginally lower temperature but was not drier than today. The enhanced contrast between the northern and southern parts of the SCS in vegetation and climate during the LGM may be ascribed, at least partly, to the strengthening of Winter Monsoon during the last glacial period.     

An Insight into Paleovegetation on the Emerged Shelf at the Last Glaciation: Pollen Date of the South China Sea

Vegetation on the emerged continental shelves of the South China Sea (SCS) during the Last Glacial Maximum (LGM) was deduced based on pollen of hemipelagic sediments from the continental slopes and the consideration of pollen transport dynamics and source areas. During the LGM (including the top of Oxygen Isotope Stage 3) the sea level might be more than 100 m lower than that of the present. Consequently, both northern and southern continental shelves of the SCS were exposed. The northern continental shelf was covered by grassland mainly of Artem/s/a. The climate should be cold and dry, whereas on the southern continental shelf (Sunda Land) was spread tropical lowland rainforest and mangroves were scattered by the river mouths and along the coast. The climate might be cooler than that in the present day, but drop of humidity was not observed.     

Vegetation Evolution in the Northern South China Sea Region Since 40 ka BP?aAn Attempt To Reconstruct Palaeovegetation Based on Biomization (in English)

egetation evolution in the northern South China Sea region since 40 500 a BP is reconstructed using biomization procedure based on pollen data from deep sea core 17940. The result shows that, it is feasible to reconstruct palaeovegetation using biomization procedure, when pollen, particularly Pinus pollen, transported by wind over long distance is excluded. Results from factor analysis suggest that humidity and temperature are the two main factors determining vegetation evolution on land around the northern South China Sea. From 40 500 a BP to 11 100 a BP, broad-leaved evergreen forest (WAMF), and montane conifers(MGRF) occurred on hills and low mountains; while steppe (STEP) predominated on the exposed shelf. The main feature of the vegetation evolution is the frequent alternation between MGRF (or WAMF) and STEP, implying abrupt changes in millennium scale between humid/cold and dry/temperate climate. All abrupt climate events could be broadly correlated with Henrich events and Dansggard-Oscherge events. One of the events around 12 700 a BP, sees the occurrence of MGRF, suggesting that climate turned humid and cold rapidly. This may be correlated with the Younger Dryas event; Broad-leaved evergreen (WAMF) predominates since 11 000 a BP. During the early Holocene and late Holocene tropical rainforest (TRFO) or tropical seasonal forest (TSFO ) occurred several times.     

Paleoenvironmental change in the middle Okinawa Trough since the last deglaciation: Evidence from the sedimentation rate and planktonic foraminiferal record

Well-dated, high-resolution records of planktonic foraminifera and oxygen isotopes from two sediment cores, A7 and E017, in the middle Okinawa Trough reveal strong and rapid millennial-scale climate changes since ∼ 18 to 17 thousand years before present (kyr B.P.). Sedimentation rate shows a sudden drop at ∼ 11.2 cal. kyr B.P. due to a rapid rise of sea level after the Younger Dryas (YD) and consequently submergence of the large continental shelf on the East China Sea (ECS) and the retreat of the estuary providing sediment to the basin. During the last deglaciation, the relative abundance of warm and cold species of planktonic foraminifera fluctuates strongly, consistent with the timing of sea surface temperature (SST) variations determined from Mg/Ca measurements of planktonic foraminifera from one of the two cores. These fluctuations are coeval with climate variation recorded in the Greenland ice cores and North Atlantic sediments, namely Heinrich event 1 (H1), Bølling–Allerød (B/A) and YD events. At about 9.4 kyr B.P., a sudden change in the relative abundance of shallow to deep planktonic species probably indicates a sudden strengthening of the Kuroshio Current in the Okinawa Trough, which was synchronous with a rapid sea-level rise at 9.5–9.2 kyr B.P. in the ECS, Yellow Sea (YS) and South China Sea (SCS). The abundance of planktonic foraminiferal species, together with Mg/Ca based SST, exhibits millennial-scale oscillations during the Holocene, with 7 cold events (at about 1.7, 2.3–4.6, 6.2, 7.3, 8.2, 9.6, 10.6 cal. kyr BP) superimposed on a Holocene warming trend. This Holocene trend, together with centennial-scale SST variations superimposed on the last deglacial trend, suggests that both high and low latitude influences affected the climatology of the Okinawa Trough.     

Environmental changes clarified by pollen and diatom proxy records in the sedimentary archive of the northwestern Japan Sea during last 21.0 kyr

High-temporal resolution pollen and diatom records from the northwestern Japan Sea document environmental changes over the last 21.0 kyr. Vegetation and climate changes were evaluated using the forest-steppe (SFI) and the pollen temperature (T_p) indices. The highest SFI occurred between ca. 21.0 ka and 16.6 ka and indicates the presence of a relatively dry climate and large areas of forest-steppe in the region. Boreal forests covered the mountain slopes. The broad-leaved trees survived in refugia located in lower mountain belts. Beginning ca. 16.6 ka, SFI decreases, while T_p increases, especially between ca. 11.0 ka and 5.7 ka. However, variations in these indices indicate fluctuating climates during the deglaciation. Significant vegetation changes occurred in the Holocene. Mixed deciduous forests with a predominance of Quercus became widely present beginning ca. 9.8 ka. The area of forest-steppe was reduced occurring only in local habitats. Pinus became one of the most common taxa in the forest ca. 5.3 ka. The geographic features of the coring area have determined in the past the persistence throughout the record of cold-water diatom flora. Cold-water diatoms have dominated in both cool and warm intervals; however, a small increase in the percentage and species diversity of warm-water diatoms was noted for warming. Low sea level during the Last Glacial Maximum (LGM) and early Holocene changed the general patterns in the sea circulation and in the vectors of the longshore currents, which transported the waters formed in the shallow areas of the northeastern and northern parts of the Japan Sea. A slight increase in sublittoral benthic diatoms indicates a lowered sea level during the LGM. The increase in sublittoral planktonic diatoms reflects a gradual rise in sea level during the Bølling–Allerød (BA) and Younger Dryas (YD). A greater component of oceanic diatom species at Holocene indicates the inflow of Pacific waters across both the Tsushima and Tsugaru straits. This study of pollen and diatom records demonstrates a clear response to climatic fluctuations and sea level changes in the Japan Sea during the Late Pleistocene and Holocene.     

Warming shelf seas drive the subtropicalization of European pelagic fish communities

Pelagic fishes are among the most ecologically and economically important fish species in European seas. In principle, these pelagic fishes have potential to demonstrate rapid abundance and distribution shifts in response to climatic variability due to their high adult motility, planktonic larval stages, and low dependence on benthic habitat for food or shelter during their life histories. Here, we provide evidence of substantial climate‐driven changes to the structure of pelagic fish communities in European shelf seas. We investigated the patterns of species‐level change using catch records from 57 870 fisheries‐independent survey trawls from across European continental shelf region between 1965 and 2012. We analysed changes in the distribution and rate of occurrence of the six most common species, and observed a strong subtropicalization of the North Sea and Baltic Sea assemblages. These areas have shifted away from cold‐water assemblages typically characterized by Atlantic herring and European sprat from the 1960s to 1980s, to warmer‐water assemblages including Atlantic mackerel, Atlantic horse mackerel, European pilchard and European anchovy from the 1990s onwards. We next investigated if warming sea temperatures have forced these changes using temporally comprehensive data from the North Sea region. Our models indicated the primary driver of change in these species has been sea surface temperatures in all cases. Together, these analyses highlight how individual species responses have combined to result in a dramatic subtropicalization of the pelagic fish assemblage of the European continental shelf.