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1.
全球变暖和人为活动不断加剧海洋低氧环境发生的频率和范围,低氧对全球海洋底栖生物群落结构造成重大影响。底栖有孔虫能够广泛适应生存在各种海洋低氧环境中,是极少数能适应低氧环境的真核生物之一,底栖有孔虫对低氧环境的响应及适应机制研究是海洋研究领域的前沿和热点话题,至今仍存在很多谜团。本文总结了不同海洋低氧环境活体底栖有孔虫分布特征、活体底栖有孔虫对人为诱导低氧环境的响应、低氧环境下底栖有孔虫外壳化学组成特征、低氧环境下底栖有孔虫的生存机理,期望为后续推进海洋低氧环境下底栖有孔虫相关研究进一步开展提供参考和借鉴。底栖有孔虫作为古海洋环境重建的重要工具,对我们了解全球海洋低氧环境的历史演化进程具有非常重要的意义。展望未来我们需要进一步加强有孔虫细胞生理学和分子生物学对低氧环境的适应机制研究,从系统发生学上认识真核生物对低氧环境适应的历史演化进程,为利用有孔虫作为工具更好地重建和预测海洋低氧环境变化提供理论依据。 相似文献
2.
冷泉区底栖有孔虫研究进展 总被引：1，自引：0，他引：1
海底冷泉区是海洋能源和生物资源同时富集的一类特殊区域。底栖有孔虫群落及其地球化学组成是海底冷泉区发育的重要指示标志之一。海底冷泉区的底栖有孔虫及其碳同位素研究,对于探讨冷泉演化、评估古冷泉甲烷排放对全球气候变化的影响有重要的研究意义。综述了全球一些主要冷泉区的底栖有孔虫研究方法及其进展,对比了各冷泉区底栖有孔虫群落结构的主要特征及地域差异,评述了冷泉区底栖有孔虫的碳同位素记录特征、影响因素及其对冷泉活动的潜在指示意义,最后提出了南海北部冷泉活动区底栖有孔虫方面的研究展望。 相似文献
3.
Syed Mohammad Saalim R. Saraswat T. Suokhrie S. R. Bhadra S. R. Kurtarkar R. Nigam 《Environmental Earth Sciences》2017,76(20):706
Being sensitive to environmental changes, foraminifera have been extensively used to monitor pollution level in the marine environment, including the effect of mining in coastal areas. In the Goa state of India, the rejects from opencast mining on land largely find their way to the estuaries, as washout during monsoon. Additionally, the Mormugao Port at the mouth of the Zuari estuary is the hub of activities due to the transport of ore from hinterland areas by barges and its subsequent loading for export. On the directive of the Supreme Court of India, all the mining-related activities abruptly stopped throughout India, including that in Goa in 2012, and got reinstated in 2015. Therefore, it provided a fit case to test the effectiveness of benthic foraminifera as an indicator of environmental impact due to mining activities. A total of ten surface sediment samples from five locations in Zuari estuary were collected from a depth range of 4.5–8.5 m in the years of 2013 and 2016 and were analyzed for both the living (stained) and dead benthic foraminifera. The year 2013 represents a time interval immediately after the closure of extensive mining activity, and the sampling during 2016 represents minimal mining. The living benthic foraminiferal abundance was higher (19–54/g sediment) during 2013 and decreased substantially during 2016 (3–22/g sediment), suggesting an adverse effect of activities associated with mine closure on benthic foraminifera. Additionally, the relative abundance of Ammonia was also significantly low during the year 2016. The temporal variation in dead foraminifera was, however, different than that of the living foraminifera. The differential response was attributed to the terrigenous dilution as a result of change in sedimentation rate. Therefore, we conclude that living foraminifera correctly incorporate the changes in mining pattern and may be used as an effective tool to monitor the impact of mining. We further suggest that the potential counter effect of terrigenous dilution on total and living benthic foraminiferal population should be considered while interpreting temporal variations in foraminiferal abundance in marginal marine settings. 相似文献
4.
Benthic foraminifera are one of the most commonly used indicators to infer paleodepth. The information on depth distribution of fossil benthic foraminifera is generally obtained from normal marine environments. However, a significant gap exists with respect to implications of benthic foraminiferal distributions in unique sedimentary successions, such as those deposited under upwelling regimes. In such settings, the paleobathymetric signal is somewhat obscured by the extreme food fluxes and oxygen depletion at the seafloor that cause changes in benthic foraminiferal assemblage composition. Nevertheless, the dynamics of upwelling systems, and as a result the sediment and organic matter accumulation, are known to be directly influenced by eustatic changes, making paleobathymetric reconstruction highly valuable for understanding these systems.The Upper Cretaceous high productivity marine succession of southern Israel, with its variable lithologies, provides a unique opportunity for addressing this issue. Through this succession, a significant turnover in the benthic foraminiferal assemblages is observed associated with a sharp change in lithology from phosphate (Phosphate Member) to organic rich carbonates (Oil Shale Member; OSM). Statistical nMDS analysis distinguished four groups of species indicative of distinct depth habitats: <200 m, 100–300 m, 300–500 m, and >500 m. Each one of these groups corresponds to different parts of the sequence. According to our analysis, the shift in the benthic foraminiferal assemblages is attributed to a distinct regional deepening from shelf environment (<200 m) in the Phosphate Member (upper Campanian) to upper bathyal (200–500 m) at the base of OSM (base Maastrichtian), and deeper to middle bathyal (>500 m) during the Maastrichtian. While taking into account other factors affecting benthic foraminiferal distribution, this study demonstrates that depth distribution models based on normal marine settings might also be applicable as proxies for paleobathymetry in high productivity environments. 相似文献
5.
地质历史时期曾发过许多对生命的演化进程造成过重大影响与制约的全球性地质事件,白垩纪—古近纪就是一个重大地质事件频发的时期。随着冈瓦纳大陆在中生代时期的解体,全球海陆格局发生了根本的变化,地球的表层和岩石圈层均发生了重大的改变,由此引发了构造运动空前活跃,发生过诸如大洋缺氧事件(OAE)、大洋富氧事件(CORBs)、白垩纪/古近纪(K/Pg)生物大灭绝事件、古新世—始新世极热(PETM)事件、印度-亚洲板块碰撞、新特提斯洋的演化及最终消亡等一系列的全球性重大地质事件。对这些重大地质事件的研究,有助于加深我们对古海洋、古地理、古环境的认识。尝试追踪和捕捉这些重大地质事件,恢复和重建古地理,其基础是建立精确的年代地层格架。西藏南部保存了中国最为完整的海相白垩纪—古近纪沉积,完整地记录了上述的全球性重大地质事件,通过对札达、岗巴、定日、亚东、江孜、萨嘎和吉隆等地区高分辨率浮游和底栖有孔虫、介形虫、钙质超微化石和放射虫生物地层学研究,可直接约束全球性重大地质事件发生的时间,并为重建新特提斯洋古海洋环境和古地理提供证据。此外,在重大地质环境突变期间生物的演化过程,也可为探明极端环境变化发生时期气候-环境-生物之间的协同演化关系提供证据。本文系统总结了课题组为主的近年来对藏南白垩纪—古近纪海相地层中微体古生物学的研究成果及重要进展,并对未来研究提出展望。 相似文献
6.
Temporal changes in benthic foraminiferal morpho-groups were suggested as an effective proxy to reconstruct past monsoon intensity from the Arabian Sea. Here, in order to test the applicability of temporal variation in morpho-groups to reconstruct past monsoon intensity from the Bay of Bengal, we have documented recent benthic foraminiferal distribution from the continental shelf region of the northwestern Bay of Bengal. Based on the external morphology, benthic foraminifera were categorized into rounded symmetrical (RSBF) and angular asymmetrical benthic foraminifera (AABF). Additionally, a few other dominant groups were also identified based on test composition (agglutinated, calcareous) and abundance (Asterorotalids and Nonions). The relative abundance of each group was compared with the ambient physico-chemical conditions, including dissolved oxygen, organic matter, salinity and temperature. We report that the RSBF are abundant in comparatively warm and well oxygenated waters of low salinity, suggesting a preference for high energy environment, whereas AABF dominate relatively cold, hypersaline deeper waters with low dissolved oxygen, indicating a low energy environment. The agglutinated foraminifera, Asterorotalids and Nonions dominate shallow water, low salinity regions, whereas the calcareous benthic foraminiferal abundance increases away from the riverine influx regions. Food availability, as estimated from organic carbon abundance in sediments, has comparatively less influence on faunal distribution in the northwestern Bay of Bengal, as compared to dissolved oxygen, temperature and salinity. We conclude that the factors associated with freshwater influx affect the distribution of benthic foraminiferal morpho-groups in the northwestern Bay of Bengal and thus it can be used to reconstruct past monsoon intensity from the Bay of Bengal. 相似文献
7.
The Late Cretaceous (Maastrichtian) to early Paleocene (Thanetian) shallow water (<100 m) agglutinated foraminifera from a section at Dakhla Oasis (Western Desert, Egypt) were analyzed for their assemblage, species and genera distribution, diversity, depositional environment, community structure and palaeobathymetry with respect to regional tectonics, climate and global eustasy. Data suggest an equitable benthic environment with low species dominance deposited in a brackish littoral and/or marsh setting. Sea level curves using characteristic benthic foraminiferal species, genera and assemblages corroborate quantitatively generated estimate and statistical analysis. Data suggests that in the absence of or of an impoverished benthic foraminiferal fauna, a high resolution agglutinated foraminiferal dataset can be as good a predictor of the benthic community structure and environment, as its calcareous counterpart, at least for shallow settings (<100 m). Present data also provides a good window in better understanding the distribution and interrelationship between the three dominant genera, Haplophragmoides, Trochammina and Ammobaculites. Faunal changes at boundaries (Cretaceous/Paleogene, Danian/Selandian and Selandian/Thanetian) are also evaluated. 相似文献
8.
深海研究中的底栖有孔虫：回顾与展望 总被引：4，自引：0，他引：4
底栖有孔虫在古环境研究中的应用先是用作古水深或水团的标志物。随着新技术的应用,识别出了2种不同的底栖有孔虫微生境：外生种和内生种;认识到甚至深海底栖有孔虫,也能对表层浮游生物勃发的季节性短暂事件作出响应,因为沉降到海底的有机物质供养着底栖有孔虫。目前,底栖有孔虫被广泛应用于估算海洋表层生产力和底层水团的含氧量。回顾了深海底栖有孔虫生态研究的历史和其在古海洋学中的应用,并强调研究、应用中的新方法、新技术。中国已经加入了诸如IODP等深海研究计划,有必要向我国学术界提供底栖有孔虫研究的新方向,以资参考。 相似文献
9.
Claudia G. Cetean Ramona B?lcMichael A. Kaminski Sorin Filipescu 《Cretaceous Research》2011,32(5):575-590
Study of an upper Santonian to upper Campanian hemipelagic succession from the southern part of the Romanian Eastern Carpathians enables us to establish an integrated biostratigraphy based on planktonic foraminifera and calcareous nannofossils and to compare this record with the agglutinated foraminiferal biozonation used for the Carpathians.Benthic foraminiferal assemblages were investigated using several methods, such as agglutinated and calcareous benthic foraminiferal morphogroups, and the benthic foraminiferal oxygen index in order to determine their response to environmental parameters in the basin (correlated with sea-level maxima documented by regional sea-level curves for the Tethys). A pattern of changes in benthic foraminiferal communities associated with increased organic carbon flux and rising sea-levels can be summarized as follows in the studied succession. As sea-level begins to rise there is an increase in the proportion of calcareous benthic foraminifera at the expense of agglutinated foraminifera within the benthic assemblages (earliest Campanian, mid-late Campanian). Once sea-level rises, an increase in the elongate keeled morphotype of agglutinated foraminifera (shallower water forms) can be observed, and if sea-level remains high for an extended period (as in the early Campanian) then an invasion of both agglutinated and benthic calcareous foraminifera characteristic of outer shelf-upper slope environments take place in the basin. The variations in tubular and deep infaunal morphotypes of agglutinated foraminifera are ascribed to varying levels of organic carbon flux. 相似文献
10.
Danuta Peryt 《地学学报》2013,25(4):298-306
Benthic and planktonic foraminifera from a marly clay intercalation sandwiched between mid‐Badenian (Middle Miocene) gypsum deposited in an environment of an evaporitic shoal (<1 m deep) at Borków (southern Poland) indicate a major marine flooding event in the previously isolated Carpathian Foredeep Basin (Central Paratethys). After this very short‐term environmental change, benthic foraminifers started to colonize a new niche which was previously defaunated, and the pattern of benthic foraminiferal colonization is similar to that related to the reflooding which terminated the Badenian evaporite deposition. The benthic foraminifer assemblages are composed of pioneer, opportunistic, r‐selected species dominated by elphidiids. The connection of the Carpathian Foredeep Basin with the marine reservoir was short‐lived. The marly clay intercalations in evaporite sequences originating in bared basins can thus register major environmental changes. 相似文献
11.
Gita R. Narayan Claire E. Reymond Marleen Stuhr Steve Doo Christiane Schmidt Thomas Mann Hildegard Westphal 《Sedimentology》2022,69(1):121-161
Large benthic foraminifera are major carbonate components in tropical carbonate platforms, important carbonate producers, stratigraphic tools and powerful bioindicators (proxies) of environmental change. The application of large benthic foraminifera in tropical coral reef environments has gained considerable momentum in recent years. These modern ecological assessments are often carried out by micropalaeontologists or ecologists with expertise in the identification of foraminifera. However, large benthic foraminifera have been under-represented in favour of macro reef-builders, for example, corals and calcareous algae. Large benthic foraminifera contribute about 5% to modern reef-scale carbonate sediment production. Their substantial size and abundance are reflected by their symbiotic association with the living algae inside their tests. When the foraminiferal holobiont (the combination between the large benthic foraminifera host and the microalgal photosymbiont) dies, the remaining calcareous test renourishes sediment supply, which maintains and stabilizes shorelines and low-lying islands. Geological records reveal episodes (i.e. late Palaeocene and early Eocene epochs) of prolific carbonate production in warmer oceans than today, and in the absence of corals. This begs for deeper consideration of how large benthic foraminifera will respond under future climatic scenarios of higher atmospheric carbon dioxide (pCO2) and to warmer oceans. In addition, studies highlighting the complex evolutionary associations between large benthic foraminifera hosts and their algal photosymbionts, as well as to associated habitats, suggest the potential for increased tolerance to a wide range of conditions. However, the full range of environments where large benthic foraminifera currently dwell is not well-understood in terms of present and future carbonate production, and impact of stressors. The evidence for acclimatization, at least by a few species of well-studied large benthic foraminifera, under intensifying climate change and within degrading reef ecosystems, is a prelude to future host–symbiont resilience under different climatic regimes and habitats than today. This review also highlights knowledge gaps in current understanding of large benthic foraminifera as prolific calcium carbonate producers across shallow carbonate shelf and slope environments under changing ocean conditions. 相似文献
12.
Hara Drinia 《Central European Journal of Geosciences》2009,1(1):1-18
Assemblages of benthic foraminifera from one clastic succession in the Afales Basin (Ithaki Island, western Greece) were investigated to reconstruct palaeoenvironmental conditions during the Oligocene. The section consists of alternating hemipelagic marls and detrital deposits, designated as flysch-like beds, attributed to biostratigraphic Zones P20 and P21. Planktic percentages are mostly high (66–80%). Benthic foraminiferal assemblages comprise calcareous and agglutinated taxa (up to 15%). The prevalence of epifaunal foraminifera indicates good ventilation of the bottom water resulting from basin morphology, which enabled the undisturbed flow of water throughout the basin. Palaeodepth estimates imply bathyal deposition, from about 800 to 1200 m deep. The benthic foraminiferal fauna is of high diversity along the section, as is expected in deep marine environments. The abundances of the most common foraminiferal taxa (Cibicidoides spp., Oridorsalis umbonatus, Gyroidinoides spp., Stilostomella spp., Nodosariidae, Nuttallides umbonifera) are quite variable and imply generally oligotrophic to mesotrophic environmental conditions with variable organic flux. 相似文献
13.
The concept of anthropogenic impact is extremely important to be considered while analysing the ecology of coast and shelf
zones. For centuries, these zones have been the epicentres for various human activities, including urbanisation, construction
of sea ports and harbours, development of natural reservoirs (including oil production and fishing), marine aquaculture, shipping,
recreation and many others. Many of the activities in progress on both sides of the shoreline provide 50% or more of the gross
State/UT (Union Tertiary) product for surrounding states. The data shows that land-based and atmospheric sources account for
about two-thirds of the total contamination found in the marine environment, constituting 44 and 33%, respectively. The greatest
anthropogenic pollution pressure undoubtedly falls on the shelf zones and coastal areas. To prove this theory, a total of
25 bottom sediment samples were collected within the depth zone of 5 fathoms from the South Andaman coastal fringe for sediment
geochemistry studies and foraminiferal analysis. The samples were further analysed for heavy metal pollutants like Co, Cu,
Mn, Pb and Zn. The study yielded 20 benthic foraminiferal species. Of these, five benthic species were living including Ammonia beccarii, Calcarine calcar, Elphidium crispum, Operculina complanata and Nonion deppresula. The presence of deformed specimens and the domination of Ammonia spp. are indications of a polluted environment. Sampled coral reefs had high abundances of Operculina spp. The highest counts of benthic microbiota were found in finer sediment. Species diversity is very limited along the coastal
fringe of South Andaman Island in comparison with fauna from the coast of India. This first report of benthic foraminifera
from South Andaman Island will allow us to assess future impacts of marine pollution because foraminiferal deformations are
positively correlated to the concentrations of heavy metals (Cr, Cu, Mn, Pb and Zn). 相似文献
14.
R. Nagendra P. Sathiyamoorthy S. Pattanayak A. Nallapa Reddy B. C. Jaiprakash 《Stratigraphy and Geological Correlation》2013,21(7):675-688
The Karai shale Formation of the Uttatur Group is exposed in a bad land area at the western margin of the Cauvery Basin. This shale has been investigated based on foraminiferal fauna and clay minerals. The foraminiferal assemblages obtained contain predominantly calcareous benthic foraminifera, rare planktic and arenaceous foraminifera. The planktic foraminiferal index taxa Planomalina buxtorfi, Rotalipora reicheli, Praeglobotruncana stephani, and Hedbergella portsdownensis suggest the late Albian to middle Turonian age. The benthic assemblage dominated by Lenticulina, Gavelinella, Osangularia and Quadrimorphina, suggests an outer neritic (100–200 m) environment. The clay mineral content dominated by kaolinite-illite-montmorillonite indicates that the Karai shale was formed from weathering of igneous rocks. 相似文献
15.
Marine stable nitrogen isotope containing much key biogeochemical information, is an important way in identifying marine nitrogen sources and understanding the marine nitrogen cycles. These isotopic signals can be preserved in marine sediments and used to trace the marine biogeochemical cycles and environment changes during geological history. Studies in recent decades have illustrated the key role of nitrogen fixation and denitrification. Because of the spatiotemporal variability and the complexity of ocean processes and nitrogen sources in the marine environment, we need to combine the modern observations with geological records, integrate oceanography, biology, and geology, and consider the hydrological environment, geological processes and climate changes, to understand the coupling between the ocean nitrogen cycle, climate and environmental changes. 相似文献
16.
海水硝酸盐氮、氧同位素组成研究进展 总被引：2，自引：0，他引：2
海洋中氮的生物地球化学循环影响着海洋生态系统的结构和功能,并和全球气候变化有着密切的联系,一直是海洋科学研究的重点和热点。海水硝酸盐的15N/14N和18O/16O比值可以反映海洋中氮循环的主要过程,因而成为研究海洋氮循环的一个重要手段。综述海水硝酸盐氮、氧同位素组成的测定方法,同化吸收作用、硝化作用、反硝化作用、生物固氮作用等氮循环过程所导致的氮、氧同位素分馏及其在海洋学研究中的应用。海洋生态系中硝酸盐氮、氧同位素的分布可以提供支持生物生产力的氮来源信息,以及氮在不同储库迁移转化的路径与机制。未来的研究需要发展适用于低含量硝酸盐的同位素测量方法,构筑海洋氮的收支平衡,掌握影响上层海洋硝酸盐氮、氧同位素变化的过程,获取全球海域有关硝酸盐氮、氧同位素组成的更多数据。 相似文献
17.
Kapesa Lokho D. S. N. Raju R. J. Azmi 《Journal of the Geological Society of India》2011,77(3):252-260
Planktic and benthic foraminifera including uvigerinids are documented from the Upper Bhuban Formation, exposed at Thingdawl
village, Kolasib district, Mizoram. The foraminiferal assemblage is poorly preserved and consists of index fossils useful
for precise biochronology and interpretation of the depositional environment. A total of ten benthic and six planktic foraminiferal
species are described. Six species belong to the genus Uvigerina, four to Ammonia, one species each of Globorotalia, Globigerinoides, Clavatorella, Praeorbulina and two species of the genus Orbulina. Based on lithological and foraminiferal assemblage, middle neritic to upper part of outer neritic paleobathymetry is inferred
for the deposition of this part of the Upper Bhuban Formation. The foraminiferal assemblage suggests late Early Miocene to
early Middle Miocene, (∼16 Ma) equivalent to planktic foraminiferal zones N8-N9 for the Upper Bhuban Formation. 相似文献
18.
A total of 103 surface sediment samples collected from the water depth range of 15—3300 m along Vijaydurg-Karwar stretch of central west coast of India were analyzed for foraminiferal content. Relict benthic foraminiferal assemblage was noted within 50—135 m water depth.The relict benthic foraminiferal assemblage that includes Amphistegina,Operculum and Alveolinetta in sediment samples within the water depth of 85—135 m indicates presence of coral reef at this depth during Early Holocene. The presence of barnacle fouling on Relict foraminifera at 60—90 m confirms the paleo-shoreline. The shallow depth zone is characterized by presence of agglutinated relict foraminifera.The agglutinated forms indicate freshwater influx,which eventually increased the sea level and subsequently deteriorated the paleo-coral reef. 相似文献
19.
对南海北部大洋钻探184航次1146站晚上新世以来底栖有孔虫属种组合的Q型因子分析, 发现底栖有孔虫组合以2.1Ma, 1.5Ma和0.7Ma为界, 分为Stilostomella-Globocassidulina subglobosa-Nodogenerina, Bulimina alazanensis, Uvigerina perigrina和Melonis barleeanus-Globobulimina affinis-Bulimina aculeata4个组合.结合底层水溶解氧含量和浮游、底栖有孔虫碳同位素分析, 认为底栖有孔虫组合的变化是南海底层水影响所致, 以及南海北部表层和底层海水营养盐含量变化的共同结果. 相似文献
20.
Yuvaraja Arumugm Anil K Gupta Mruganka K Panigrahi 《Journal of Earth System Science》2014,123(7):1671-1680
Deep-sea benthic foraminifera are an important and widely used marine proxy to understand paleoceanographic and paleoclimatic changes on regional and global scales, owing to their sensitivity to oceanic and climatic turnovers. Some species of benthic foraminifera are sensitive to changes in water mass properties whereas others are sensitive to organic fluxes and deep-sea oxygenation. Benthic faunal diversity has been found closely linked to food web, bottom water oxygen levels, and substrate and water mass stability. The present study is aimed at analyzing species diversity trends in benthic foraminifera and their linkages with Indian monsoon variability during the Neogene. Species diversity of benthic foraminifera is examined in terms of number of species (S), information function (H), equitability (E) and Sanders’ rarefied values, which were combined with relative abundances of high and low productivity benthic foraminifera at Ocean Drilling Program Hole 730A, Oman margin, western Arabian Sea. The Oman margin offers the best opportunity to understand monsoon-driven changes in benthic diversity since summer monsoon winds have greater impact on the study area. The species diversity was higher during the early Miocene Climatic Optimum (～17.2–16.4 Ma) followed by a decrease during 16.4–13 Ma coinciding with a major increase in Antarctic ice volume and increased formation of Antarctic Bottom Water. All the diversity parameters show an increase during 13–11.6 Ma, a gradual decrease during 11.6–9 Ma and then an increase with a maximum at 7 Ma. Thereafter the values show little change until 1.2 Ma when all the parameters abruptly decrease. The benthic foraminiferal populations and diversity at Hole 730A were mainly driven by the Indian monsoon, and polar waters might have played a minor or no role since early Neogene period as the Arabian Sea is an enclosed basin. 相似文献