Emerging problems in the coastal zone for the twenty-first century     

Edward D. Goldberg 《Marine pollution bulletin》1995,31(4-12):152-158

The continued availability of some marine resources is threatened by the increased fluxes to the oceans of identifiable and measurable collections of pollutants, which include plant nutrients, plastics, environmental oestrogens, and organisms contained in ship-ballast waters. Characteristic of these societal discards that will guide research progress are long residence times; slow accumulation rates; increasing fluxes with time; and dissemination over large areas. The resolution of these problems will require data collections over decadal time-scales. Finally, some classical and some perceived marine pollution problems, such as those involving specific metals, can now be discontinued in the face of the absence of unacceptable impacts on living organisms.  相似文献   

Choice of conodont Idiognathodus simulator （sensu stricto） as the event marker for the base of the global Gzhelian Stage （Upper Pennsylvanian Series,Carboniferous System）   总被引：3，自引：0，他引：3  

Philip H. Heckel  ;Aleksandr S. Alekseev  ;James E. Barrick  ;Darwin R. Boardman  ;Natalya V. Goreva  ;Tatiana N. Isakova  ;Tamara I. Nemyrovska  ;Katsumi Ueno  ;Elisa Villa  ;David M. Work 《《幕》》2008,31(3):319-325

We propose that the level at which the conodont species Idiognathodus simulator （Ellison 1941） （sensu stricto） first appears be selected to mark the base of the Gzhelian Stage, because we believe that this is the optimal level by which this boundary can be correlated. This taxon has a short range and a wide distribution, as shown by correlation of glacial-eustatic cyclothems across the Kasimovian-Gzhelian boundary interval among Midcontinent North America and the Moscow and Donets basins of eastern Europe, based on scale of the cyclothems along with several aspects of biostrati- graphy. Outside of these areas, I. simulator （sensu stricto） is known also from other parts of the U.S., and is reported from the southern Urals and south-central China in its expected position between other widespread taxa. Its first appearance is consistent with the current ammonoid placement of the boundary （first appearance of Shumardites cuyleri）, and it is also compatible with certain aspects of the distribution of Eurasian fusulinid faunas （e.g., lectotype ofRauserites rossicus）.  相似文献   

Climate change projections for the Texas High Plains and Rolling Plains     

Modala  Naga Raghuveer  Ale  Srinivasulu  Goldberg  Daniel W.  Olivares  Miriam  Munster  Clyde L.  Rajan  Nithya  Feagin  Rusty A. 《Theoretical and Applied Climatology》2017,129(1-2):263-280

Potential changes in future climate in the Texas Plains region were investigated in the context of agriculture by analyzing three climate model projections under the A2 climate scenario (medium–high emission scenario). Spatially downscaled historic (1971–2000) and future (2041–2070) climate datasets (rainfall and temperature) were downloaded from the North American Regional Climate Change Assessment Program (NARCCAP). Climate variables predicted by three regional climate models (RCMs) namely the Regional Climate Model Version3–Geophysical Fluid Dynamics Laboratory (RCM3-GFDL), Regional Climate Model Version3–Third Generation Coupled Global Climate Model (RCM3-CGCM3), and Canadian Regional Climate Model–Community Climate System Model (CRCM-CCSM) were evaluated in this study. Gaussian and Gamma distribution mapping techniques were employed to remove the bias in temperature and rainfall data, respectively. Both the minimum and maximum temperatures across the study region in the future showed an upward trend, with the temperatures increasing in the range of 1.9 to 2.9 °C and 2.0 to 3.2 °C, respectively. All three climate models predicted a decline in rainfall within a range of 30 to 127 mm in majority of counties across the study region. In addition, they predicted an increase in the intensity of extreme rainfall events in the future. The frost-free season as predicted by the three models showed an increase by 2.6–3.4 weeks across the region, and the number of frost days declined by 17.9 to 30 %. Overall, these projections indicate considerable changes to the climate in the Texas Plains region in the future, and these changes could potentially impact agriculture in this region.

  相似文献   

Radiative and collisional processes in CNA 2Π i     

Joshua B. Halpern  Yuhui Huang  Tatiana Titarchuk 《Astrophysics and Space Science》1996,236(1):11-17

In the last four years we have carried out a number of studies on the radiative and collisional processes in theA ² _i state of CN. Many of these of interest to those studying planetary atmospheres, comets and solar spectra are summarized in this paper. Data for CNA ² _i fluorescence lifetimes and quenching rates, and collisional energy transfer between CNA ² _i andX ²₊ are reported. Detailed comparisons and a discussion of the results may be found in several already published papers.  相似文献   

Life-history traits of the symbiotic scale-worm Branchipolynoe seepensis and its relationships with host mussels of the genus Bathymodiolus from hydrothermal vents     

Temir A. Britayev  Daniel Martin  Elena M. Krylova  Rudo von Cosel  & Tatiana S. Aksiuk 《Marine Ecology》2007,28(1):36-48

Associations between scale‐worms and giant mussels are common constituents of hydrothermal vent and cold seep ecosystems, but very little is known about their nature and ecology. Here, we analyze the ecological characteristics of the associations between Branchipolynoe seepensis, an obligate symbiotic polychaete, and their host mytilid mussels Bathymodiolus puteoserpentis and B. azoricus inhabiting hydrothermal vent fields on the Mid‐Atlantic Ridge. Infested mussels generally harbored a single symbiont (<4% had two to six worms). Infestation rate varied from 7.2% to 76.5%, increasing with mussel size, and was significantly lower for B. puteoserpentis. Symbiont density at Lucky Strike ranged between 1071 and 1191 individuals m⁻². Female symbiont size was always positively correlated with host size, while only males and juveniles from small mussels showed the same trend. This suggested a relatively long‐lasting host/symbiont association for females and short‐lasting association with successive reproductive migrations for adult males. The sex ratio of symbionts was always biased in favor of females. Males were smaller and more slender than females and had one mode in their size distributions, whereas females typically had three or more modes, suggestive of a longer life span in females. Between 59.1% and 72.2% of mussels had damaged soft tissues with substantially higher incidence of trauma in infested ones, suggesting that symbionts may cause trauma. The symbionts also induce tunnel‐like structures among the ctenidia, indicating fidelity to a particular location inside the host. Based on our data, together with the fact that infested mussels became relatively wider than non‐infested ones, this association is considered parasitic (likely kleptoparasitic). Our data, together with those from previous studies, allowed us to define the main life‐history traits of B. seepensis: (i) the relationship with their host is parasitic, (ii) the association begins at the smallest mytilid size classes, (iii) there is sexual dimorphism in body size, (iv) sex ratio deviates from 1:1 in favor of females, (v) fertilization occurs through temporal pairing and pseudocopulation, (vi) sperm are stored by females, (vii) eggs are large (likely lecithotrophic or with direct development), (viii) females have a longer life span than males, (ix) adult males may be semalparous, undertaking reproductive migrations followed by a short period of pairing and then death, and (x) females have a semi‐continuous iteroparous reproductive cycle.  相似文献   

Scavenging of particulate matter in coastal waters     

H. Weiss  M. Koide  K. K. Bertine  E. D. Goldberg   《Marine Chemistry》1991,32(2-4)

The uptake of a suite of 19 metals from coastal seawaters upon both glass and Teflon surfaces reflected primarily the sorption of particulate matter derived from crustal rock weathering. Uptake for all elements was greater in the light than in the dark. Based upon these and earlier results, a new definition of scavenging for environmental systems is proposed.  相似文献   

Volcanic stratigraphy of DSDP/ODP Hole 395A: An interpretation using well-logging data   总被引：1，自引：0，他引：1  

Bartetzko  Anne  Pezard  Philippe  Goldberg  David  Sun  Yue-Feng  Becker  Keir 《Marine Geophysical Researches》2001,22(2):111-127

Deep Sea Drilling Project/Ocean Drilling Program Hole 395A was drilled approximately 500 m deep into young oceanic crust west of the Mid-Atlantic Ridge. Core recovery is very poor in this hole and therefore continuous downhole measurements are important to understand the drilled lithology. Geophysical downhole measurements were carried out during several cruises. A new set of logs was recorded during Leg 174B in summer 1997. The new logging data show a significant improvement in data quality compared to older measurements from Leg 109. The lithostratigraphy established from cores gives only limited information because of the poor core recovery in this hole. The gaps in the core lithostratigraphy are filled by reconstructing a synthetic lithological profile using the standard well-logging data. Three types of lava morphologies, massive basalts, altered lava flows, and pillow basalts, may be distinguished using the logs because the lava morphologies show differences in their physical properties due to differences in fracturing and alteration. The synthetic lithological profile gives a more detailed and precise vertical definition of single layers than the core profile. The integration of further logging and core data enables a detailed reconstruction of the accretion history at the drill site. Cyclic, upward decreasing trends in the resistivity logs were already observed during earlier cruises and were referred to magmatic cycles. Similar trends occur in the density log and, inversely, in the total gamma ray log. The trends reflect gradual changes in fracturing, porosity, permeability, and alteration and cover depth intervals of several tens of meters. Boundaries between cycles are interpreted to correspond to periods of volcanic quiescence. Two types of boundaries may be identified. Boundaries correlating with reversals in the magnetic field and/or changes in the geochemical composition of the basalts are interpreted as long pauses. Basalts separated by these boundaries were probably fed by separate magma reservoirs. Boundaries identified only by changes in alteration but not in geochemistry are interpreted to represent shorter pauses. They separate basalts that were probably fed by the same magma chamber. This revised version was published online in November 2006 with corrections to the Cover Date.  相似文献   

会徽——地质学会的文化表达     

张井飞  文恒  Tatiana FEKLOVA  张九辰 《地质论评》2023,69(4):2023040008-2023040008

会徽是一种行业标识、一段历史烙印、一个学术品牌,它作为一种信息载体,以简单、形象、易识别的图像表达了学术团体的学术宗旨和使命,同时彰显了学术团体的工作目标、学术精神等科学文化内涵。本文以中国地质学会会徽为分析案例,通过与东西方几个代表性国家地质学会的文化宗旨与会徽内涵的比较,探讨会徽在学会科学文化建设中的作用。  相似文献   

Proterozoic mafic magmatism in Siberian craton: An overview and implications for paleocontinental reconstruction     

Dmitry P. Gladkochub  Sergei A. Pisarevsky  Tatiana V. Donskaya  Richard E. Ernst  Michael T.D. Wingate  Ulf Söderlund  Anatoliy M. Mazukabzov  Eugene V. Sklyarov  Michael A. Hamilton  John A. Hanes 《Precambrian Research》2010

We present a summary of late Paleoproterozoic to Neoproterozoic mafic magmatism in the Siberian craton, including recently published U–Pb and ⁴⁰Ar–³⁹Ar dates. These new precise ages suggest that at least some of the previously published K–Ar ages of Siberian mafic bodies should be ignored. The time–space geochronological chart, or the ‘barcode’ of mafic magmatic events shows significant differences between northern and southern Siberia. Both are characterized by ∼1900–1700 Ma magmatic events, but then there was an almost 1 Ga mafic magmatic ‘pause’ in south Siberia until ∼800 Ma. Meanwhile there are indications of multiple mafic magmatic events in North Siberia (Anabar shield and Olenek uplift) between ∼1600 and 1000 Ma. A series of magmatic events probably related to the breakup of Rodinia occurred in southern Siberia after ∼800 Ma. So far, there are no indications of late Neoproterozoic mafic magmatism in North Siberia. Ca. 1000–950 Ma mafic sills were reported from Meso- to Neo-Proterozoic sedimentary successions in the Sette-Daban area on the east side of the Siberian craton, but their tectonic setting is debated. Recent Ar–Ar dates of ∼1750 Ma for NW-trending dykes in the Aldan and Anabar shields, together with similar-age NNE-trending Baikal uplift dykes in south-eastern Siberia suggest the existence of a giant radial dyke swarm possibly related to a mantle plume centred in the Vilyui River area.  相似文献   

Mafic Late Miocene–Quaternary volcanic rocks in the Kamchatka back arc region: implications for subduction geometry and slab history at the Pacific–Aleutian junction     

Anna O. Volynets  Tatiana G. Churikova  Gerhard Wörner  Boris N. Gordeychik  Paul Layer 《Contributions to Mineralogy and Petrology》2010,159(5):659-687

New ⁴⁰Ar/³⁹Ar and published ¹⁴C ages constrain voluminous mafic volcanism of the Kamchatka back-arc to Miocene (3–6 Ma) and Late Pleistocene to Holocene (<1 Ma) times. Trace elements and isotopic compositions show that older rocks derived from a depleted mantle through subduction fluid-flux melting (>20%). Younger rocks form in a back arc by lower melting degrees involving enriched mantle components. The arc front and Central Kamchatka Depression are also underlain by plateau lavas and shield volcanoes of Late Pleistocene age. The focus of these voluminous eruptions thus migrated in time and may be the result of a high fluid flux in a setting where the Emperor seamount subducts and the slab steepens during rollback during terrain accretions. The northern termination of Holocene volcanism locates the edge of the subducting Pacific plate below Kamchatka, a “slab-edge-effect” is not observed in the back arc region.  相似文献