Tolerance of allogromiid Foraminifera to severely elevated carbon dioxide concentrations: Implications to future ecosystem functioning and paleoceanographic interpretations     

Joan M. Bernhard  Elizabeth Mollo-Christensen  Nadine Eisenkolb  Victoria R. Starczak 《Global and Planetary Change》2009,65(3-4):107-114

Increases in the partial pressure of carbon dioxide (pCO₂) in the atmosphere will significantly affect a wide variety of terrestrial fauna and flora. Because of tight atmospheric–oceanic coupling, shallow-water marine species are also expected to be affected by increases in atmospheric carbon dioxide concentrations. One proposed way to slow increases in atmospheric pCO₂ is to sequester CO₂ in the deep sea. Thus, over the next few centuries marine species will be exposed to changing seawater chemistry caused by ocean–atmospheric exchange and/or deep-ocean sequestration. This initial case study on one allogromiid foraminiferal species (Allogromia laticollaris) was conducted to begin to ascertain the effect of elevated pCO₂ on benthic Foraminifera, which are a major meiofaunal constituent of shallow- and deep-water marine communities. Cultures of this thecate foraminiferan protist were used for 10–14-day experiments. Experimental treatments were executed in an incubator that controlled CO₂ (15 000; 30 000; 60 000; 90 000; 200 000 ppm), temperature and humidity; atmospheric controls (i.e., ~ 375 ppm CO₂) were executed simultaneously. Although the experimental elevated pCO₂ values are far above foreseeable surface water pCO₂, they were selected to represent the spectrum of conditions expected for the benthos if deep-sea CO₂ sequestration becomes a reality. Survival was assessed in two independent ways: pseudopodial presence/absence and measurement of adenosine triphosphate (ATP), which is an indicator of cellular energy. Substantial proportions of A. laticollaris populations survived 200 000 ppm CO₂ although the mean of the median [ATP] of survivors was statistically lower for this treatment than for that of atmospheric control specimens. After individuals that had been incubated in 200 000 ppm CO₂ for 12 days were transferred to atmospheric conditions for ~ 24 h, the [ATP] of live specimens (survivors) approximated those of the comparable atmospheric control treatment. Incubation in 200 000 ppm CO₂ also resulted in reproduction by some individuals. Results suggest that certain Foraminifera are able to tolerate deep-sea CO₂ sequestration and perhaps thrive as a result of elevated pCO₂ that is predicted for the next few centuries, in a high-pCO₂ world. Thus, allogromiid foraminiferal “blooms” may result from climate change. Furthermore, because allogromiids consume a variety of prey, it is likely that they will be major players in ecosystem dynamics of future coastal sedimentary environments.  相似文献   

全拖曳式深海直流电阻率法三维任意各向异性正演模拟     

杨志龙  殷长春  张博  刘云鹤  任秀艳  惠哲剑 《吉林大学学报(地球科学版)》2018,48(6):1845-1853

高精度、高效率的深海勘探是当前国家海洋资源勘探开发的研究热点之一,设计观测效率高、勘探成本低的探测方式,开发可精确计算海底复杂电性环境的正演模拟算法有助于推进该研究的进展。本文基于前人的研究经验,引入了全拖曳式深海直流电阻率观测方式,同时考虑到海底沉积环境的电各向异性,开发了基于非结构有限元方法的三维任意各向异性深海直流电阻率正演算法,实现了对海底任意电各向异性情况的仿真模拟。本文算法与层状一维模型半解析解的对比验证了算法的精度。对典型各向异性电性模型的仿真模拟和分析,证明了全拖曳式深海探测方式对海底沉积层和矿产资源电各向异性的高分辨率。在此基础上,总结了电导率各向异性主轴沿笛卡尔坐标旋转时视电阻率分布也发生同方向旋转的视电阻率分布特征,并根据海底地形对各向异性探测的影响进行了简单探讨。  相似文献   

均匀来流下尾翼型抑振装置效果试验研究     

李朋  郭海燕  王飞  张永波 《海洋工程》2017,35(2):89-97

基于控制尾流,阻止立管尾流漩涡脱落转换路径的涡激振动抑制机理,设计三角形尾翼、片状尾翼及交错尾翼等三种抑振装置。三种抑振装置分别安装于立管模型表面,立管模型采用外径为18 mm的透明有机玻璃管。通过在均匀流场中进行安装有该抑振装置的立管模型涡激振动试验,研究三种抑振装置对立管涡激振动的抑制效率,并通过与配重裸管的涡激振动数据对比,分析抑振装置对立管动力响应的影响规律。研究结果表明,三种抑振装置均取得了明显的抑振效果,与配重裸管相比,安装片状尾翼及交错尾翼的立管模型抑制效率可达90%以上,安装三角形尾翼后立管模型振动频率略有减小,而安装片状尾翼及交错尾翼的立管模型没有明显的主导频率。  相似文献   

世界大洋地质与矿产标准物质评介   总被引：2，自引：0，他引：2       下载免费PDF全文

王毅民王晓红  高玉淑张学华 樊兴涛 《中国地质》2010,37(1):229-243

自20世纪80年代中以来,中国相继研制了4批共11个大洋地质与矿产标准物质,形成了多金属结核(GSPN-1～3)、海山富钴结壳(GSMC-1～3)、富钴结壳的铂族元素(MCPt-1,2)和深海沉积物(GSMS-1～3)4个标准物质系列。笔者简介了这些标准物质的研制背景,评介了中国和世界其他国家(美国、俄罗斯、印度和日本等)研制的大洋地质与矿产各标准物质系列,对比了其定值数据、特点及应用。虽然中国的研制工作起步较晚,但由于采用了更先进的分析测试技术和国内外多实验室合作定值方式,使这些标准物质定值组分多、系列性好,也有较大国际影响。  相似文献   

An Effective Method to Determine the Distribution Boundary of Cobalt-Rich Fe-Mn Crusts on a Guyot： Synchronous Application of Sub-bottom Profiling and Deep-Sea Video Recording     

HeGaowen LiangDonghong SongChengbin SunXiaoming WuShuigen ZhouJianping ZhangXuehua 《中国地质大学学报(英文版)》2005,16(2):178-182

Cobalt richferromanganesecrust,hereaftercalled Fe Mncrust,isoneoftheimportantmarinemineralre sourcesintheinternationalseabed.Fe Mncrustoccurs onthesurfaceofseamounts,whichareenrichedinco balt,nickel,copper,platinumgroupelements,rare earthelementsandothe…  相似文献   

Last interglacial and Holocene climatic development in the Norwegian Sea region: Ocean front movements and ice-core data     

Hans Petter Sejrup  Haflidi Haflidason  Dorthe Klitgaard Kristensen  Sigfus J. Johnsen 《第四纪科学杂志》1995,10(4):385-390

Planktonic foraminiferal evidence suggests that the ocean front systems between Polar and Atlantic surface waters in the Norwegian Sea generally were located closer to Greenland during Oxygen Isotope Substage 5e than in the Holocene. During both these periods oscillations have occurred in the position of the fronts. In the western Norwegian Sea region, the substage 5e influence of warm Atlantic waters was interrupted by a return to polar conditions. These findings support both ice-core data and evidence from Europe that the last interglacial was a period of rapid climatic shifts.  相似文献   

Terrigenous sedimentation processes along the continental margin off NW Africa: implications from grain-size analysis of seabed sediments   总被引：2，自引：0，他引：2  

Christine Holz  Jan–berend W. Stuut  Rüdiger Henrich 《Sedimentology》2004,51(5):1145-1154

The terrigenous fraction of seabed sediments recovered along the north‐west African continental margin illustrates spatial variability in grain size attributed to different transport mechanisms. Three subpopulations are determined from the grain‐size analyses (n = 78) of the carbonate‐free silt fraction applying an end‐member modelling algorithm (G. J. Weltje, 1997). The two coarsest end‐members are interpreted as representing aeolian dust, and the fine‐grained end‐member is related to fluvial supply. The end‐member model thus allows aeolian fallout to be distinguished from fluvial‐sourced mud in this area. The relative contributions of the end‐members show distinct regional variations that can be related to different transport processes and pathways. Understanding present‐day sediment dispersal and mixing is important for a better understanding of older sedimentary records and palaeoclimate reconstructions in the region.  相似文献   

Deep-sea corals evidence periodic reduced ventilation in the North Atlantic during the LGM/Holocene transition     

Andrea Schröder-Ritzrau  Augusto Mangini 《Earth and Planetary Science Letters》2003,216(3):399-410

Nine new intermediate water ages estimated with coupled uranium-series and radiocarbon measurements on deep-sea corals from the northeastern Atlantic are presented. Together with six intermediate and deep-water ages from the western North Atlantic [Adkins et al., Science 280 (1998) 725-728] and one from the equatorial Atlantic [Mangini et al., Nature 392 (1998) 347-348] they span the time period from 15?400 to 560 yr ago and show abrupt variations of intermediate and deep-water ages from 270 up to 2320 yr. Both major pulses of meltwater discharge MWP 1A, following Heinrich Event 1 and MWP 1B after the Younger Dryas cold event are followed by enhanced supply of southern source water at intermediate depths in the North Atlantic, together with reduced formation of well-ventilated glacial North Atlantic intermediate water (1000-2000 m). This result gives strong support to numerical models, predicting fast and sharp increase of bottom water age in the Atlantic triggered by pulses of freshwater discharge into the North Atlantic [Rahmstorf, Nature 372 (1994) 82-85; Stocker and Wright, Radiocarbon 40 (1998) 359-366].  相似文献   

青藏高原东北缘黄土的气候演化与高原隆升的耦合   总被引：3，自引：2，他引：3       下载免费PDF全文

谢远云  李长安张序强周 嘉 《中国地质》2003,30(4):436-441

通过对青藏高原东北缘的民和黄土的磁化率、粒度、CaCO3和TOC等气候载体进行综合测试分析，可以将青藏高原东北缘黄土1．90～0．70MaB．P．段划分出7个气候阶段。对民和黄土的气候分析表明，1．10MaB．P．(民和黄土的L11黄土层)前气候差异较小，冬夏季风不强，对抗性较弱，黄土古土壤发育不明显，厚度较薄；10MaB．P．后，冬夏季风对抗性迅速增强，气候差异性增强。将民和黄土与其他地区以及深海沉积物氧同位素记录进行对比可以发现，民和黄土的S8、S9和S10古土壤分别与深海氧同位素21、23和25阶段较好地对应，而L9、L10和L11则分别对应22、24和26阶段。L11黄土层以下的黄土记录与深海氧同位素记录的可比性不是很明显。同时，民和黄土的高分辨率气候记录与青藏高原的阶段性隆升有较好的耦合关系。  相似文献   

Lecithotrophic nauplius of the family Dirivultidae (Copepoda; Siphonostomatoida) hatched on board over the Mid-Atlantic Ridge (5°S)     

Viatcheslav N. Ivanenko  Pedro Martínez Arbizu  & Jens Stecher 《Marine Ecology》2007,28(1):49-53

Abstract A copepod nauplius of the family Dirivultidae Humes & Dojiri 1980 is described for the first time. The lecithotrophic nauplius of the widespread symbiotic copepod Stygiopontius pectinatus Humes 1987 was released from females bearing paired egg sacs that included only one yolky embryo each. The ovigerous females of S. pectinatus were washed from the branchial chamber of alvinocaridid shrimps ( Rimicaris exoculata Williams & Rona 1986 ) collected at a deep-sea hydrothermal field on the Mid-Atlantic Ridge at 5° S (Red Lion site, chimney 'Shrimps Farm', depth 3,048 m) by ROV Quest 4000 and maintained in a laboratory on the R/V METEOR (cruise M64/1, 2005). The nauplius of S. pectinatus , appears to be a stage I nauplius because it bears only one pair of caudal setae and the setose bud of maxilla 1 is absent. Like nauplii of other copepods of the order Siphonostomatoida, this nauplius of S. pectinatus possesses a reduced labrum and the body is filled with yolky granules; it also lacks a masticatory process on the antennal coxa. The presence of two inner setae (instead of one seta) on the mandibular endopod is hypothesized to be a primitive character of dirivultids that distinguishes them from the remaining siphonostomatoid genera. The Dirivultidae is a widespread and diverse family of copepods endemic to the deep-sea hydrothermal vents of the Pacific and Atlantic Oceans. Morphological features of the planktonic nauplius of S. pectinatus suggest nutritional independence during their dispersal.  相似文献