Ice volume and sea level during the last interglacial

During the last interglacial period, ~125,000 years ago, sea level was at least several meters higher than at present, with substantial variability observed for peak sea level at geographically diverse sites. Speculation that the West Antarctic ice sheet collapsed during the last interglacial period has drawn particular interest to understanding climate and ice-sheet dynamics during this time interval. We provide an internally consistent database of coral U-Th ages to assess last interglacial sea-level observations in the context of isostatic modeling and stratigraphic evidence. These data indicate that global (eustatic) sea level peaked 5.5 to 9 meters above present sea level, requiring smaller ice sheets in both Greenland and Antarctica relative to today and indicating strong sea-level sensitivity to small changes in radiative forcing.     

当归在大别山地区引种栽培试验初报

评估甘肃岷归在大别山地区引种栽培的可行性。方法：试验地点设在大别山地区海拔860m和1060m^2处,每处分生地试验和熟地试验2个处理,每个处理设遮荫和不遮荫两种措施;试验分2a进行,第1a育苗,第2a移栽。结果：当归在海拔1060m处的生地生长良好,遮荫处理的当归生长势好于未遮荫的。结论：甘肃岷归在海拔高于1000m以上的大别山地区适合生长,可在该地区引种栽培。     

秋季马铃薯高产高效栽培技术初探

秋季马铃薯在贵州省桐梓县海拔800m以下地区,常年种植有2000.0hm2,也是贵州省桐梓县秋冬蔬菜的组成部分。该技术是充分利用脱毒马铃薯高产创建项目,在县域海拔400、600、800m3个区域开展试验探索的初步总结,前茬作物为玉米、水稻或蔬菜。     

Oceanographic observations of the 1982 warming of the tropical eastern pacific

Moored current meter, sea level, hydrographic, and surface drifter measurements show the large changes that took place in the eastern tropical Pacific during the onset of the warm episode of 1982. In August the near-surface flow at 0 degrees , 110 degrees W reversed direction to eastward. By October the sea surface temperature in the equatorial zone increased by 5 degrees Celsius above the long-term monthly mean value, sea level rose by 22 centimeters at the Galápagos Islands, and the thermocline was displaced downward by 50 to 70 meters along the equator and the South American coast.     

金强河地区豆科牧草引种试验报告

1983—1985年,在海拔高度约3千米的甘肃省天祝基金强河地区进行了豆科牧草引种试验。通过对48个豆科牧草供试材料的生育期、越冬率、产草量等性状的观测研究,初步筛选出抗寒性强、越冬性较好的呼盟黄花苜蓿、昭盟黄花苗蓿 x 杂种苜蓿、杂种苜蓿、草原Ⅰ号苜蓿、润布勒苜蓿五个材料,供生产上试种。通过试验,说明越冬前灌水和覆盖处理对提高豆科牧草越冬率有良好作用。此外,还观察到了一些具有放牧型品种特征的,以及长穗的,可作为有价值的育种材料加以利用。     

Eustatic sea level 120,000 years ago on oahu, hawaii

Extensive dating of the fossil corals associated with the Waimanalo shoreline on Oahu has shown that 120,000 years ago the ocean was approximately 7.6 meters above its present level. Corals grown during that time constitute a major portion of the subaerial reef-derived material on the island, with exposures ranging from about 10 meters to near sea level. This evidence corroborates the notion that 120,000 years before the present was the last time during which the sea stood significantly higher than it does today. The reported benches at 3.7, 1.5, and 0.6 meters, if not of Recent origin, could be features created by brief halts of the sea during rapid regression shortly after the Waimanalo high stand.     

Transient Circulation Event near the Deep Ocean Floor

On 24 January 1968, a transient deep-circulation event was recorded by a triangular array of autonomous current recorders installed 3 meters above the bottom at two of the three positions and at intervals of 3 to 1000 meters above the bottom at the third position in a depth of 3950 meters above the relatively smooth floor of the eastern North Pacific. The event interrupted a 24-hour record of relatively steady but peculiar conditions, lasted for about 1(1/2) hours, and was followed by current directions and speeds that greatly differed from those of the initial period. The event occurred over a volume of the sea of at least 2 kilometers in horizontal dimensions and 1 kilometer thick. Associated with the event were many small clockwise-rotating features extending from 3 to at least 1000 meters above the bottom and a rapidly increasing current velocity at 1000 meters. The event was probably local and may have involved convective motion, internal waves, and the passage of front. Some of the changes in horizontal velocity may have resulted from the combined effects of upwelling and the earth's rotation.     

Indication of increasing solar ultraviolet-B radiation flux in alpine regions

Measurements at the Jungfraujoch High Mountain Station (Swiss Alps, 47 degrees N, 3576 meters above sea level) indicate that there has been a slight increase of about 1 percent per year in the flux of solar ultraviolet-B radiation (290 to 330 nanometers) since 1981. A Robertson-Berger detector was used to measure solar erythemal radiation. The increase can be related to a long-term ozone depletion.     

山陕峡谷张家湾2 3 0k aB P以来黄土记录的环境信息

对山陕峡谷张家湾村蔚汾河阶地上沉积的黄土地层粒度—磁化率进行分析发现:沉积物的粒度—磁化率变化曲线能够很好地反映黄土—古土壤地层序列的变化.粒径小于5μm和大于40μm组份的体积分数曲线分别是夏季风和冬季风的良好替代性指标,通过粒度分析所绘制的各粒级组份体积分数曲线显示,古土壤S2、S1和Sm发育时期,东亚夏季风加强,粒径小于5μm组份的体积分数增大;黄土L2和L1堆积时期,冬季风有所加强,粒径大于40μm组份的体积分数增大.张家湾剖面的黄土记录只能在万年尺度上与深海氧同位素记录进行对比,整体上反映了最近230ka以来山陕峡谷东亚季风的演化过程.     

The Phanerozoic record of global sea-level change

We review Phanerozoic sea-level changes [543 million years ago (Ma) to the present] on various time scales and present a new sea-level record for the past 100 million years (My). Long-term sea level peaked at 100 +/- 50 meters during the Cretaceous, implying that ocean-crust production rates were much lower than previously inferred. Sea level mirrors oxygen isotope variations, reflecting ice-volume change on the 10(4)- to 10(6)-year scale, but a link between oxygen isotope and sea level on the 10(7)-year scale must be due to temperature changes that we attribute to tectonically controlled carbon dioxide variations. Sea-level change has influenced phytoplankton evolution, ocean chemistry, and the loci of carbonate, organic carbon, and siliciclastic sediment burial. Over the past 100 My, sea-level changes reflect global climate evolution from a time of ephemeral Antarctic ice sheets (100 to 33 Ma), through a time of large ice sheets primarily in Antarctica (33 to 2.5 Ma), to a world with large Antarctic and large, variable Northern Hemisphere ice sheets (2.5 Ma to the present).     

Long-term sea-level fluctuations driven by ocean basin dynamics

Earth's long-term sea-level history is characterized by widespread continental flooding in the Cretaceous period (approximately 145 to 65 million years ago), followed by gradual regression of inland seas. However, published estimates of the Late Cretaceous sea-level high differ by half an order of magnitude, from approximately 40 to approximately 250 meters above the present level. The low estimate is based on the stratigraphy of the New Jersey margin. By assimilating marine geophysical data into reconstructions of ancient ocean basins, we model a Late Cretaceous sea level that is 170 (85 to 270) meters higher than it is today. We use a mantle convection model to suggest that New Jersey subsided by 105 to 180 meters in the past 70 million years because of North America's westward passage over the subducted Farallon plate. This mechanism reconciles New Jersey margin-based sea-level estimates with ocean basin reconstructions.     

Quaternary climates and sea levels of the u.s. Atlantic coastal plain

Uranium-series dating of corals from marine deposits of the U.S. Atlantic Coastal Plain coupled with paleoclimatic reconstructions based on ostracode (marine) and pollen (continent) data document at least five relatively warm intervals during the last 500,000 years. On the basis of multiple paleoenvironmental criteria, we determined relative sea level positions during the warm intervals, relative to present mean sea level, were 7 +/- 5 meters at 188,000 years ago, 7.5 +/- 1.5 meters at 120,000 years ago, 6.5 +/- 3.5 meters at 94,000 years ago, and 7 +/- 3 meters at 72,000 years ago. The composite sea level chronology for the Atlantic Coastal Plain is inconsistent with independent estimates of eustatic sea level positions during interglacial intervals of the last 200,000 years. Hydroisostatic adjustment from glacial-interglacial sea level fluctuations, lithospheric flexure, and isostatic uplift from sediment unloading due to erosion provide possible mechanisms to account for the discrepancies. Alternatively, current eustatic sea level estimates for the middle and late Quaternary may require revision.     

北美红杉造林对比试验研究

研究不同因子对北美红杉生长影响的试验结果表明：不同海拔高度、不同坡向、不同立地条件对北美红杉生长均产生较为显著的影响，海拔1300m的生长较好；南坡生长较东南坡好；龙陵试验点树高最大增幅达28．7cm；贵阳试验点地径最大增幅达0．39cm。     

Sea-level lowering during the illinoian glaciation: evidence from a bahama "blue hole"

Stalagmites have been recovered from 45 meters below sea level in an underwater karstic cave ("blue hole") near Andros Island in the Bahamas. Uranium series ages, corrected for contamination of the sample by young marine carbonate replacements, show that the speleothem was deposited between 160,000 and 139,000 years before the present. This period corresponds to the Illinoian glacial event and demonstrates that sea level must have been lowered by at least 42 meters (allowing for subsidence) from its present position during this time.     

Revisiting carbon flux through the ocean's twilight zone

The oceanic biological pump drives sequestration of carbon dioxide in the deep sea via sinking particles. Rapid biological consumption and remineralization of carbon in the "twilight zone" (depths between the euphotic zone and 1000 meters) reduce the efficiency of sequestration. By using neutrally buoyant sediment traps to sample this chronically understudied realm, we measured a transfer efficiency of sinking particulate organic carbon between 150 and 500 meters of 20 and 50% at two contrasting sites. This large variability in transfer efficiency is poorly represented in biogeochemical models. If applied globally, this is equivalent to a difference in carbon sequestration of more than 3 petagrams of carbon per year.     

Ocean warming and sea level rise along the southwest u.s. Coast

Hydrographic time-series data recorded during the past 42 years in the upper 500 meters off the coast of southern California indicate that temperatures have increased by 0.8 degrees C uniformly in the upper 100 meters and that temperatures have risen significantly to depths of about 300 meters. The effect of warming the surface layer of the ocean and there by expanding the water column has been to raise sea level by 0.9 +/- 0.2 millimeter per year. Tide gauge records along the coast are coherent with steric height and show upward trends in sea level that vary from about 1 to 3 millimeters per year.     

不同环境下藏獒幼犬生长发育规律的初步研究

选择1月龄幼犬60条(公、母各半),分别在高海拔地区(1 500 m)和平原地区进行试养,饲养管理水平相同,通过测定1-10月龄幼犬的体质量、体尺等指标对2个地区幼犬的生长发育指标进行了比较.结果表明:3、4月龄高海拔地区的幼犬体质量比平原地区分别高5.33、.7 g,相对生长率比平原地区高3.6%和3.5%,差异达极显著水平(P<0.01).体尺发育规律分析发现:1-6月龄幼犬的体长生长速度高于胸围,8-10月龄胸围、体高的生长速度远大于体长.据此认为,环境对藏獒幼犬体质量、体高、体长的影响显著.     

Elephant teeth from the atlantic continental shelf

Teeth of mastodons and mammoths have been recovered by fishermen from at least 40 sites on the continental shelf as deep as 120 meters. Also present are submerged shorelines, peat deposits, lagoonal shells, anz relict sands. Evidently elephants and other large mammals ranged this region during the glacial stage of low sea level of the last 25,000 years.     

West antarctic ice sheet: present-day thinning and holocene retreat of the margins

Retreat of the margins of the West Antarctic ice sheet associated with rising sea level during the last 15,000 years is the main cause for the thinning of the ice sheet by approximately 300 meters. The West Antarctic ice sheet during the late Wisconsin was at least 30 percent wider than it is today, and Holocene retreat of its margins has added about 6 meters to the world sea level.     

模拟增温对华北农田土壤碳排放的影响

为研究增温效应下农田温室气体排放的变化和机制,选择华北平原的山东禹城农田生态系统国家野外科学观测研究站当地典型的冬小麦-夏玉米农田为研究对象,设计翻耕增温(CTW)处理和翻耕不增温(CTN)对照开展多年增温试验。2014年10月出苗期至2015年12月冬小麦越冬期持续增温,2016年初至2016年9月增温设备因故障关闭。结果显示,2014—2015年,冬小麦期土壤温度显著增加1.31℃(P<0.05),夏玉米期土壤温度升高0.71℃(P>0.05),而全年土壤体积含水量均值对增温无显著响应,仅越冬期土壤含水量增加明显。两年期内,增温抑制冬小麦季CO2累积排放达20.35%,以3月和5月差异表现最为明显。2014—2016年冬小麦季,CTW、CTN处理的年均CH4累积吸收量分别为1641.2、2185.7 g·hm^-2,增温抑制冬小麦季CH4吸收,但对夏玉米季CH4通量无显著作用。冬小麦季增温降低CTW处理土壤微生物生物量碳值达26.55%,而微生物生物量氮仅个别施肥和灌溉月份对增温响应显著。两年期冬小麦和夏玉米季CTW、CTN地上生物量均值分别为12.19、16.33 mg·hm^-2和16.41、21.18 mg·hm^-2,表明增温降低了地上作物生物量。研究表明,长期增温显著抑制小麦季土壤CO2释放和CH4吸收,但玉米期碳排放和吸收的响应相对较弱。增温条件下,土壤水热条件和生物量依然是限制土壤碳通量的重要因素。