bluuebunny/crossref_metadata_2025_split huggingface dataset:
Global terrestrial productivity in the Mesozoic era
Authors: Beerling D. J. 
Published: April 2008

Abstract

This paper describes a global-scale modelling approach for investigating the structure and productivity of terrestrial vegetation in the Mesozoic era. General circulation model (GCM) palaeoclimate simulations (by the University of Reading) for Kimmeridgian and Cenomanian time are described as driving datasets for the University of Sheffield Dynamic Global Vegetation Model (SDGVM). The validity of these GCM palaeoclimates is reviewed. Global patterns of terrestrial net primary productivity (NPP) and leaf area index (LAI) have been simulated with the SDGVM, which models plant physiological processes and the biogeochemical cycling of carbon and nitrogen in soils and vegetation. An important feature of this modelling approach is that it requires no underlying map of soils or vegetation type. Global NPP in Kimmeridgian and Cenomanian time was high (117.6 and 106.8 Gt Ca
−1
, respectively) compared with the present-day level (57.0 Gt Ca
−1
). The high concentrations of atmospheric CO
2
at each interval significantly influenced the NPP and LAI of Mesozoic vegetation, to an extent dependent on climate. CO
2
effects on the structure of vegetation in Kimmeridgian and Cenomanian time were sufficient to markedly influence key land surface variables required by GCMs for climate predictions, and point to the need to include direct CO
2
-vegetation interactions in climate models. Two approaches to testing the modelled NPP patterns were devised, one using palaeobotanical information on tree growth, and the other based on a comparison of measurements and predictions of the stable carbon isotope ratios of fossil plants. Both approaches provided some support for the global-scale simulations, indicating the feasibility of modelling vegetation activity in ancient climates from a knowledge of present-day processes.
The Maastrichtian (Late Cretaceous) climate in the Northern Hemisphere
Authors: Golovneva Lena B. 
Published: April 2008

Abstract
This investigation of the Maastrichtian climate in the Northern Hemisphere is based on taxonomic and ecological studies of fossil floras, leaf physiognomy and the distribution of dinosaurian faunas. Fossil plant evidence indicates that the climate during Maastrichtian time was warm temperate at high and middle latitudes, and subtropical south of 40°N. Precipitation was relatively high (about 700–800 mm) and evenly distributed over the year. The annual range of temperatures was similar to that of modern maritime climates, but the latitudinal gradient was lower than at present. At high latitudes cold-month mean temperatures were about 3–4°C and probably never dropped below 0°C for extended periods. It seems that these comparatively mild winter temperatures in polar regions were a result of the heating of these areas by warm oceanic upwelling.
An integrated micropalaeontological approach applied to Late Pleistocene-Holocene palaeoclimatic and palaeoenvironmental changes (Gaeta Bay, Tyrrhenian Sea)
Authors: Amore F. O. , Ciampo G. , Di Donato V. , Esposito P. , Russo Ermolli E. , Staiti D. 
Published: April 2008

Abstract
An integrated micropalaeontological approach has been used to characterize the last climatic cycle in the Tyrrhenian Sea. Three gravity cores, drilled in the Gaeta Bay continental shelf, have been analysed by means of quantitative methods applied to different taxonomic groups. In particular, calcareous nannofossils, planktonic Foraminifera, ostracods and palynomorphs have been studied to detect palaeoclimatic trends. The Last Glacial period has been identified in the lower part of two cores (C8 and C9), and an older cold period is represented in the lower part of the more proximal core (C5). The upper part of all the cores clearly records the Holocene period, whereas the Late Glacial period is not always easily detectable. Pollen seems to precede the Holocene climatic optimum. Climatic curves have been reconstructed for all the taxonomic groups and high-resolution palaeobathymetric reconstruction has been inferred on the basis of the ostracod assemblages.
Late Glacial and Post-Glacial pollen records and inferred climatic changes from Lake Balaton and the Great Hungarian Plain
Authors: Nagy-Bodor E. , Járai-Komlódi M. , Medve A. 
Published: April 2008

Abstract
In Hungary, the Great Plain and the western part of Transdanubia had different geomorphological and climatic characteristics during the Late Glacial, the Holocene and the present day. As a result, the vegetation in the two areas was also different, as indicated by palynological data. In Late Glacial times the Great Plain had an extremely continental climate whereas the western part of Transdanubia had a somewhat milder one. This clear distinction can be made on the basis of pollen spectra between the palaeo-vegetation of Transdanubia and that of the Great Plain.

A comparison of the pollen data, and the climatic changes indicated by the carbonate content, and δ
18
O
PDB
and δ
13
C
PDB
isotope ratios of the sediments of Lake Balaton, have shown that these data can be correlated beginning from the Bölling, the onset of permanent water coverage.
Pollen analysis of the Acerno palaeo-lacustrine succession (Middle Pleistocene, southern Italy)
Authors: Ermolli Elda Russo 
Published: April 2008

Abstract

Pollen analysis has been performed on a 98 m core recovered in the palaeo-lake of Acerno (Campania, Italy). This study identified four main vegetation zones that can be correlated with Quaternary climatic events. In particular, one interglacial-glacial cycle was recorded in the succession the duration of which was estimated at around 100 ka. The interglacial period (Zone 2) is characterized by large amounts of deciduous and altitudinal forest elements; Mediterranean xerophytes are rather rare because of the distance from the palaeo-sea coast. The interglacial-glacial transition (Zone 3) shows a very rapid decrease of the arboreal taxa and a contemporaneous increase in the frequency of the non-arboreal element. The genus
Pinus
, excluded from the pollen totals, shows its highest percentage and concentration values during the transition. The glacial period (Zone 4) is characterized by the dominance of herbaceous and steppe elements, and by rather large amounts of
Pinus
. The floral composition of the analysed succession allows a late mid-Pleistocene age to be proposed for the Acerno palaeo-lake.
Were climatic changes a driving force in hominid evolution?
Authors: Chaline J. , Durand A. , Dambricourt Malassé A. , David B. , Magniez-Jannin F. , Marchand D. 
Published: April 2008

Abstract

A comparison of externalist and internalist approaches in hominid evolution shows that the externalist approach, with its claim that climate was responsible for the appearance of bipedalism and hominization, now seems to be ruled out by the biological, palaeogeographical, palaeontological and palaeoclimatic data on which it was based. Biological data support the embryonic origin of cranio-facial contraction, which determined the increase in cranial capacity and the shift in the position of the
foramen magnum
implying bipedalism. In the internalist approach, developmental biology appears as the driving force of hominid evolution, although climate exerts a significant influence and was involved in the following ways: (1) in the prior establishment of ecological niches that allowed the common ancestor to become differentiated into three subspecies; (2) by dividing up the area of distribution of species, resulting in the present-day subspecies of gorillas and chimpanzees; (3) by facilitating relative fluctuations of the geographical areas of distribution of the various species, particularly the spread of australopithecines across the African savanna from north (Chad, Ethiopia) to south (South Africa); (4) by determining adaptive geographical differentiations among
Homo erectus
and
Homo sapiens
(pigmentation, haemoglobin, etc.).
Late Quaternary vertebrate taphocoenoses from cave deposits in southeastern Austria: responses in a periglacial setting
Authors: Fladerer Florian A. 
Published: April 2008

Abstract

Forty-seven species of birds and at least 78 mammalian taxa from caves in the extant submontane vegetational zone close to the periphery of the Middle and Late Pleistocene Alpine maximum glacial expansion are comprehensively summarized for the first time. The communities of the last glacial period show sympatries of today’s boreal-tundra species with those of East European to Central Asian steppe-communities and to a lesser extent with those of temperate woodlands. Shifts in the individual species’ ranges during the last glacial period (Würm Glacial) can be partly correlated with the climatic fluctuations in the Eastern Alps as they were observed sedimentologically and glaciologically. Analyses of high-resolution uppermost Pleniglacial/Late Glacial taphocoenoses (
c.
14–12 ka
bp
) in the Styrian foothills demonstrate a distinctly greater faunal diversity and reflect more diversified vegetational biota than in the Holocene. The evidence of Middle and Upper Palaeolithic human populations within the region is outlined. The presented results provide a foundation for subsequent and comparative studies in diversity and community changes in the adjacent regions.
Groundwater in headwaters: hydrological and ecological significance
Authors: Soulsby C. , Malcolm R. , Malcolm I. 
Published: April 2008

Abstract

The hydrological and ecological significance of groundwater has generally been under-estimated in headwater catchment studies within the Celtic regions. The paper presents data from headwater catchments in both upland and lowland settings in northern Scotland to address this gap in our understanding. Research in the 10 km
2
Allt a’ Mharcaidh catchment in the western Cairngorms has demonstrated that a range of groundwater sources in various drift deposits can account for
c.
50% of annual runoff, even in a high altitude headwater stream. Despite the traditional assumption that upland catchments have limited aquifer storage, oxygen isotope studies of groundwater imply mean water residence times of up to five years which indicate a range of groundwater sources in montane environments. Moreover, hydrogeochemical reactions in the saturated zone appear to regulate stream water chemistry at moderate and low flows. In such montane environments, groundwater discharges at springs create unique wetland habitats which often form the source of headwater streams and affect riparian areas. In lowland catchments the hydrological significance of groundwater is equally important. In addition, recent studies in a salmon spawning stream in the Newmills Burn, Aberdeenshire has shown that aquifer-stream interactions in hyporheic zones are crucial in maintaining habitat conditions conducive to the survival of salmonid eggs, and the subsequent population of salmon streams. It is concluded that interdisciplinary studies incorporating hydrogeological investigations are fundamental to a proper understanding of the hydrology and functional ecology of catchment systems in the Celtic regions.
Groundwater vulnerability mapping in Scotland: modifications to classification used in England and Wales
Authors: Lewis M. A. , Lilly A. , Bell J. S. 
Published: April 2008

Abstract

The recently published groundwater vulnerability map of Fife is the first in a series of maps for the Scottish Environment Protection Agency (SEPA), which includes the unpublished maps of the areas around Dumfries and Strathmore. Based on the methodology used on the Environment Agency maps of England and Wales, the lithology and permeability of the geological formations, and the physical and chemical properties of the soils are classified to produce 15 groundwater vulnerability classes. However, the Scottish maps incorporate several modifications that improve their accuracy and usefulness. These are:

(a)
the geological formations are classified solely on the basis of their permeability and do not also incorporate aquifer potential;

(b)
the occurrence of low permeability drift deposits at the surface are shown over the whole of the map area instead of only where they overlie aquifers;

(c)
areas where borehole data indicate that significant thicknesses of low permeability deposits are present in the drift sequence are shown. In these areas groundwater in the underlying solid rock formations may have a lower risk of contamination than indicated by the vulnerability zones. This is particularly useful information where the clay occurs beneath permeable drift deposits. The borehole distribution is shown to give an indication of the reliability of the boundaries;

(d)
nitrate vulnerable zones are shown;

(e)
the leaching potential classification of soils with organic surface layers has been improved.
Groundwater protection zone delineation at a large karst spring in western Ireland
Authors: Deakin J. 
Published: April 2008

Abstract

Pouladower Spring is a large karst spring in County Clare, Ireland which is being considered for use as a public supply. Groundwater protection zones have been delineated as a water quality management strategy for the spring. The Irish national groundwater protection scheme methodology is adapted to take account of the hydrological and hydrogeological complexities of the karst regime. The catchment area for the spring is large (approximately 380 km
2
) and comprises the zones of contribution for two major outlets of water, the spring and the River Fergus. The actual zone of contribution to the spring varies with different water level conditions and the risk to the source from any point within the catchment, at any given time, is less than that for a conventional groundwater source. The catchment area is highly vulnerable, but dilution and sedimentation occurring in the lakes up gradient of the source, the high throughput, and the contribution from fissures outside the main flow conduits have helped maintain good water quality at the spring. The source is considered to be a combination of both groundwater and surface water as they are intricately inter-linked throughout the catchment. An Inner Protection Area is delineated which does not provide the 100-days travel time to the source required by the national scheme, as this would be impractically large and over-protective. Rather, it delineates the area of highest hydrogeological risk to the source and should allow the local authority sufficient time to act in the event of an accidental spill. A certain degree of microbial contamination is inevitable in a karst regime and treatment is essential, as it would be for a surface water source. The remainder of the catchment is classed as an Outer Protection Area. These protection areas are then combined with the vulnerability in a GIS to give groundwater protection zones which will be used by the planners, in conjunction with groundwater protection responses, to control potentially contaminating activities.
Influent rivers: a pollution threat to Schwyll Spring, South Wales?
Authors: Hobbs Steven L. 
Published: April 2008

Abstract
A number of influent rivers cross the southern outcrop of the Carboniferous Limestone in South Wales. They lose a proportion of their flow to groundwater via both discrete sinks and leaky river beds. These influent rivers represent a pollution threat to local springs that is dependent upon many factors including antecedent conditions, pollutant type, the location of pollutant loss and the nature and volume of influent flow. An attempt is made to define the catchment area of Schwyll Spring public water supply, near Bridgend in South Wales, prior to considering the potential for pollution from influent rivers.
Groundwater resources in the Quaternary deposits and Lower Palaeozoic bedrock of the Rheidol catchment, west Wales
Authors: Hiscock K. , Paci A. 
Published: April 2008

Abstract
An assessment of the groundwater potential of the River Rheidol catchment in west Wales is presented, a region where groundwater is an important source of water to Aberystwyth. An alternative approach to a conventional well inventory was undertaken based on the manipulation of data within a geographic information system (GIS). The GIS application revealed that, in the lower reaches of the catchment, 25% of the total recorded abstractions fall on the boundaries between different geological units and, of these, two-thirds relate to the contact between Quaternary deposits and bedrock. These abstractions are typically correlated with spring sources and represent small domestic supplies from shallow, brick-lined pits dug into the valley sides. Simple catchment water balance calculations showed that groundwater abstractions are minor in comparison to total combined surface and groundwater runoff.
Compared with the weathered and fractured bedrock, the floodplain gravel aquifer is of greater significance and is further enhanced by an unquantified amount of induced recharge from the River Rheidol. However, the resource contained in the Quaternary gravels is vulnerable to mainly agricultural contaminants derived either from direct leaching through the thin unsaturated zone, especially on the floodplain, or from induced recharge from the River Rheidol.
Some case histories of geophysical downhole logging to examine borehole site and regional groundwater movement in Celtic regions
Authors: Buckley David K. 
Published: April 2008

Abstract
Many Celtic regions comprise hard fractured rock aquifers and hilly terrain. They are generally regions which have also been affected by repeated glaciation and deglaciation during the Pleistocene period. This has influenced their hydraulic properties and the groundwater flow systems which have developed. Geophysical borehole logging provides a useful method to examine the occurrence of groundwater, water inflows and the movement of water in local and regional groundwater flow systems. The downhole measurements show that wellbore flow, aquifer layering and separate groundwater circulations are common features of the hydrogeology.
Cretaceous-Palaeogene ocean and climate change in the subtropical North Atlantic
Authors: Norris Richard D. , Kroon Dick , Huber Brian T. , Erbacher Jochen 
Published: April 2008

Abstract

Ocean Drilling Program (ODP) Leg 171B recovered continuous sequences that yield evidence for a suite of ‘critical’ events in the Earth’s history. The main events include the late Eocene radiolarian extinction, the late Palaeocene benthic foraminiferal extinction associated with the Late Palaeocene Thermal Maximum (LPTM), the Cretaceous-Palaeogene (K-P) extinction, the mid-Maastrichtian event, and several episodes of sapropel deposition documenting the late Cenomanian, late Albian and early Albian warm periods. A compilation of stable isotope results for foraminifera from Leg 171B sites and previously published records shows a series of large-scale cycles in temperature and δ
13
C trends from Albian to late Eocene time. Evolution of δ
18
O gradients between planktic and benthic foraminifera suggests that the North Atlantic evolved from a circulation system similar to the modern Mediterranean during early Albian time to a more open ocean circulation by late Albian-early Cenomanian time. Sea surface temperatures peaked during the mid-Cretaceous climatic optimum from the Albian-Cenomanian boundary to Coniacian time and then show a tendency to fall off toward the cool climates of the mid-Maastrichtian. The Albian-Coniacian period is characterized by light benthic oxygen isotope values showing generally warm deep waters. Lightest benthic oxygen isotopes occurred around the Cenomanian-Turonian boundary, and suggest middle bathyal waters with temperatures up to 20 °C in the North Atlantic. The disappearance of widespread sapropel deposition in Turonian time suggests that sills separating the North Atlantic from the rest of the global ocean were finally breached to sufficient depth to permit ventilation by deep waters flowing in from elsewhere. The Maastrichtian and Palaeogene records show two intervals of large-scale carbon burial and exhumation in the late Maastrichtian-Danian and late Palaeocene-early Eocene. Carbon burial peaked in early Danian time, perhaps in response to the withdrawal of large epicontinental seas from Europe and North America. Much of the succeeding Danian period was spent unroofing previously deposited carbon and repairing the damage to carbon export systems in the deep ocean caused by the K-P mass extinction. The youngest episode of carbon exhumation coincided with the onset of the early Eocene Warm Period and the LPTM, and has been attributed to the tectonic closure of the eastern Tethys and initiation of the Himalayan Orogeny.
No extinctions during Oceanic Anoxic Event 1b: the Aptian-Albian benthic foraminiferal record of ODP Leg 171
Authors: Holbourn Ann , Kuhnt Wolfgang 
Published: April 2008

Abstract
Outstandingly well-preserved benthic foraminiferal successions from upper Aptian-lower Albian sediments at Site 1049 (Leg 171, Blake Nose escarpment, western North Atlantic) provide a detailed record of the faunal turnover across Oceanic Anoxic Event 1b (OAE 1b). Changes in abundance, diversity and species composition reflect strong fluctuations in carbon flux and bottom-water oxygenation. Before the onset of black shale sedimentation, the originally diverse assemblages are replaced by low-diversity associations, dominated by species inferred to be opportunistic phytodetritus feeders and thriving on an enhanced carbon flux to the sea floor. The 46 cm thick laminated black shale horizon corresponding to OAE 1b is virtually devoid of benthic formainifers or contains highly impoverished assemblages, suggesting that intense eutrophication and/or strong stratification triggered near anoxia at the sea floor during black shale deposition. Above the black shale, reoccurrence of the pre-black shale fauna points to relatively rapid bottom-water reoxygenation. The benthic formainiferal record of Leg 171 provides clear evidence that no major extinctions occurred across OAE 1b, as most of the species occurring below the black shale reappear above it. In contrast to other Cretaceous anoxic events, OAE 1b may have been more limited in duration or in geographical and water-depth extent, allowing recolonization from adjacent, more hospitable areas, once local conditions improved at the sea floor. Prolific radiation within the suborder Rotaliina and diversification of Textulariina with calcareous cement appear to have started in the Aptian time before OAE 1b, and continued into early Albian time to give rise to many of the modern lineages.