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© The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). The level of the Caspian Sea is influenced by rivers mostly from the high latitudes of the Northern hemisphere and therefore any change of its catchments including temperature and precipitation directly reflects on Caspian Sea-level. We reconstructed Late Pleistocene to Holocene Caspian Sea-level by a multi-disciplinary approach from a 27.7m long core in the SE corner of the Iranian Caspian coast in the Gomishan Lagoon. Late Pleistocene deposits containing typical Pleistocene fauna and dated around 20,120 cal yr BP bordered with a major hiatus indicating sea-level fall. Lagoonal deposits with shells dated at around 10,590 cal yr BP suggest that, after this deep lowstand, an initial transgression started, leading to landward advance of barrier–lagoon systems which still continued without any lowstand until 8400 cal yr BP. This corresponded to a biofacies change from lagoonal to the deeper biofacies including diatom and Gastropoda species. Around 8400 cal yr BP sea-level started to fall again, and reddish oxidized sediments with abundant foraminifera (Ammonia beccarii) record a regressive phase around 7700 cal yr BP. The mid-Holocene between 15.7 and 4.9 depths is characterized by a shallow marine environment mostly with high carbonate and gypsum contents, and lagoonal and highstand tract with no subaerial facies. The upper part of the core above a 4.9 m depth reflects at least five Late Holocene Caspian Sea-level cycles from 3260 cal yr BP onward. The Caspian Sea-levels are influenced both by global and regional events. The Oceanography Institute and Cultural Heritage Tourism Organization of Mazandaran.

International audience; Spatial patterns and trends in the concentration and quality of dissolved organic matter (DOM) are characterised across a tropical agricultural catchment using ultraviolet (UV)-visible absorbance, and fluorescence spectroscopy. Related determination of the environmental isotopes 18O and 2H clarify the dynamics of catchment water movement. Water samples were collected from the Kinabatangan River, Borneo, and selected tributaries in August and September 2008 in four regions with oil palm plantations (KB1, KB2, KB3 and KB4). The isotopic compositions of surface waters suggest that canals were characterised by a strong evaporative effect than tributaries and streams with more natural,forested vegetation. DOM was characterised by variations in UV absorbance and spectral slope. Individual fluorescence excitation–emission matrices were decomposed by Parallel Factor Analysis (PARAFAC) and three components extracted (C1, C2 and C3). Components C2 and C3 both appear to be derived from microbial sources and/or photo-degradation. The PARAFAC components indicate a clear trend of increasing DOM degradation as waters pass through the catchment. It is hypothesised that upstream DOM is rapidly photo and microbially degraded to less fluorescent DOM, while DOM concentration and character of DOM downstream is controlled by the hydrology, specifically by variations in the rate of water movement.

Relative changes in Holocene sea level are reconstructed from foraminiferal assemblages in seven cores recovered from the intertidal zone of North Norfolk (Eastern England). A total of 33 radiocarbon and infra-red stimulated luminescence dates provide a detailed chronological framework for these changes. A transfer function approach, developed from modern UK foraminiferal datasets, establishes a series of 21 new sea-level index points for this coastline which are combined with 18 existing index points and a further number of limiting values. Errors associated with changing tidal ranges through the Holocene are reduced by adopting recently developed tidal models for this period. This new approach allows the use of foraminiferal assemblages to be extended from the upper saltmarsh environment (traditionally used for sea-level studies) to lower elevations in the tidal frame and include clastic detrital sediments. The results confirm the previously observed trend of continuously rising sea-levels in this area during the last 10 000 years which is consistent with a Glacial Isostatic Adjustment model. Relative sea-level (RSL) rises from an observed minimum of approximately − 13.50 m OD at about 7500 cal. BP to approximately − 4.0 m at about 5300 cal. BP, which equates to a mean rise of c. 4.3 mm yr− 1. Subsequently, RSL rose gradually to present levels, although there is evidence that a minor reverse in this trend occurred between 4000 and 2000 cal. BP when sea-level fell by about 1 m to c. − 3.5 m. The rate of land subsidence for North Norfolk is 0.54 ± 0.03 mm yr− 1 (inverse of Late-Holocene sea-level rise).

We present a reconnaissance study of sublittoral ostracods from a number of Caspian Sea core-tops collected during a joint French–Russian scientific cruise in 1994 (cores from between 13 and 875 m water depth). The modern ostracods show little depth restriction and this reflects the hydrography of the Caspian Sea which maintains relatively constant conditions (> 5 °C, 13‰ salinity) below 50 m throughout the year. We also present the ostracod faunal record from a 10 m core of laminated sediments, recovered from the Central Caspian Basin (at a water depth of 475 m), which we believe shows repetitive, quasi-cyclic changes in bottom-water conditions over approximately the last 14–15,000 years with a major change at about the late Glacial to Holocene transition. The faunal record from this core illustrates the potential of these sediments for reconstructing environmental changes in the Caspian region during the late Quaternary to Holocene. The continuous occurrence of in situ benthic meiofauna throughout the core also indicates that the bottom-water must have remained ventilated throughout this period although variability in the faunal assemblages may reflect long and short-term changes in the strength of ventilation.

Ostracoda (microscopic, aquatic Crustacea) from brackish waters have a great potential for ecological monitoring and palaeoenvironmental analyses in highly variable environments. This has been proven in many articles during recent decades but their potential has yet to be fully developed or utilised. The analysis of ostracod assemblage composition, species distributions, eco-phenotypic variability and the analysis of stable isotopes and trace elements in ostracod shells provide valuable information on present and past water salinity, temperature and chemistry, hydrodynamic conditions, substrate characteristics, climate, sea level variations, oxygen and nutrient availability. This article provides an overview on the application of ostracods from brackish waters for palaeoenvironmental reconstruction in the Quaternary and for environmental studies in present day environments.

This paper reports the results of the excavation of an Early Bronze Age cist cemetery on the mid-Northumberland coast at Howick. The Bronze Age site was discovered during the investigation of a Mesolithic hut site, the latter having been published separately as a monograph. A total of five cists were found with only one being adult-sized, the rest presumably for infants. Due to the acidic conditions on the site, only a few fragments of a small skull were found in Cist 2. Other small finds included a small sherd of Food Vessel urn in an area of disturbance next to Cist 5, smoothed limestone cobbles and some nodules of yellow ochre. Flints were found in most of the feature fills, but these are considered to be residual as they are directly comparable to the narrow blade material found within the Mesolithic hut and its environs. The siting of Early Bronze Age cist burials in coastal locations is thought to reflect contemporary settlement on the coastal margin and its hinterland. With no Bronze Age dwelling s...

Over recent decades ostracods have become established indicators of ecosystem health, biodiversity and environmental change. With applications ranging across the earth sciences (from modern pollution studies to sea-level change, basin evolution, plate tectonics, palaeoceanography) and related disciplines such as archaeology, ecology and genetics, their utility extends to almost every aquatic and semi-aquatic habitat, from the deep ocean to high mountain springs. Their temporal range is now known to cover the last 500 million years of earth history.The study of fossil ostracod assemblages follows traditional palaeontological lines of investigation, including taphonomy, morphometries and diversity, but there are a number of methodological approaches, specific to the ostracods, that render them potentially one of the most versatile organisms in the fossil record. Ostracods have been employed on a range oftemporal and spatial scales to reconstruct past environments, from world-wide, geological-scale global events in the deep-sea through to smaller-scale studies of lakes and their archives of local environmental change over recent centuries.Much information can be obtained from ostracod assemblages but it is particularly through recent advances in the chemical and physical study of single shells or carapaces that the utility of these organisms has been brought to the fore. In this paper the potential palaeoenvironmental information derived from an ostracod assemblage, a single species, or an individual shell is reviewed. The main applications for ostracods are outlined for marine and non-marine ecosystems. Finally, the role of the ostracods in detailing the recent history of the Aral Sea is outlined.

Hydraulic redistribution, redistribution of water upward or downward within a soil profile through roots as a consequence of root-soil water potential gradients, can be an important mechanism in transporting chemical signals (i.e. abscisic acid) to the shoot for stomatal closure or in maintaining the root system during dry periods of partial rootzone drying (PRD). PRD involves alternate irrigation to two sides of a plant root system. The study reported here investigated the occurrence and magnitude of hydraulic redistribution in glasshouse-grown potatoes (Solanum tuberosum L.) under PRD. Deuterium labelled water was applied to only one half of the root system to field capacity at tuber initiation. The roots from the drying side of the dual pot were extracted at 3, 6, 12, 18 and 24 h following watering by the dry sieving method. Water from the roots was extracted by azeotropic distillation and analysed for hydrogen isotope ratios. Hydraulic redistribution occurred the most at night when stomatal conductance was considerably lower and leaf water potential was higher (less negative). The magnitude of the redistributed water, however, did not exceed 3.5%, indicating limited water redistribution under PRD. The observed water redistribution would probably be of little significance for the survival of roots present in the upper drier portion of the soil under higher water demanding conditions but its role in sending the chemical signals to the shoot to conserve water by reducing transpiration would be of particular significance during drying periods of partial rootzone drying.

A thick (c.1368 m) Upper Triassic to Lower Jurassic sedimentary sequence from exploration well L134/5-1, offshore Inner Hebrides, has yielded a rich and diverse foraminiferal and ostracod microfauna. Many of the taxa have been previously described throughout northwest Europe. Poor preservation (often due to crushing and/or overgrowth) and low numbers preclude a complete taxonomic review of this material, although changes in the faunal composition, rates of faunal turnover and palaeoenvironmental analyses are discussed. This is the first published account of ostracod and foraminiferal assemblages from the Sea of Hebrides and they indicate that the sediments (argillaceous, arenaceous and carbonates) were deposited in a shelf-marine setting with environmental fluctuations that are possibly the result of local relative sea-level changes.

Boomer, I., Whatley, R., Bassi, D., Fugagnoli, A., Loriga, C. (2001). An Early Jurassic oligohaline ostracod assemblage within the marine carbonate platform sequence of the Venetian Prealps, NE Italy. Palaeogeography Palaeoclimatology Palaeocology, 166(3-4), 331-344.

This paper presents multi-proxy palaeolimnological analyses from recent sediments in the nine CASSARINA lakes in northernmost Africa, three from each of Morocco, Tunisia, and Egypt. The lakes are diverse, ranging from hypersaline to brackish lagoons and fresh-water lakes from high to low conductivity and pH. The macrofossils analysed include fruits, seeds, and vegetative remains of plants, lagoon and fresh-water Mollusca, a range of other aquatic animals, and from one site in each country, Ostracoda and Foraminifera. The diverse macrofossils are multi-proxy indicators of environmental change, and demonstrate changes in response to human activities in the catchments of all the lakes. The three Egyptian Nile Delta lakes have received massive inputs of fresh-water due to modifications of the flow of the R. Nile culminating in the Aswan High Dam built in 1964. Elsewhere, water withdrawal is frequently a serious threat. One lake with high biodiversity in Morocco has been drained and cultivated, and a rare acid-water lake in Tunisia is in danger of drying up. The internationally famous Garaet El Ichkeul in Tunisia, which was so important for birds, has become permanently saline with a loss of diversity. All the lakes are affected by agricultural and/or urban run-off and are experiencing changes as a result of human activities. Several are in a marginally sustainable condition, whereas others are permanently damaged.

A review of the literature on the taxonomy of Triassic and Early Jurassic cytheracean Ostracoda reveals that the validity of many genera is questionable. A number of studies of the Triassic microfaunas from eastern European sequences have, in particular, obscured the true generic and suprageneric classification of many ostracod taxa. The present study concentrates on the diverse extant cytheracean family the Cytheruridae, whose origins are in the earliest Mesozoic–latest Palaeozoic, but it is clear that many contemporary cytheracean families present similar problems. This review clarifies the previous taxonomic confusion and obfuscation by demonstrating that many of these genera are spurious having been erected on specific rather than generic morphological criteria. Many of them are best accommodated within the extant genus Eucytherura Müller, 1894. Most of the cytherurid genera known from the Liassic deposits of NW Europe can be traced back to these Triassic assemblages. In considering the origin and earliest evolution of the Cytheruridae, we note that some Triassic taxa share characteristics typical of both the Cytheruridae and the Bythocytheridae and it is suggested that the former may have arisen from the latter family during the latest Permian or earliest Triassic. We also note that the palaeoenvironmental interpretation of many of the Triassic deposits is brackish-water, marginal marine.

Formerly the fourth largest inland water body in the world, the volume and area of the Aral Sea have decreased dramatically over the past 30 yr largely as a result of human actions. Throughout its approximately 2 million year history the fate of this water body has been intimately linked with that of its two main in-flowing rivers, the Amu Darya and the Syr Darya. We present a review of the hydrological, palaeontological and sedimentological evidence for the evolution of the Aral Sea based largely on Russian literature. Although the structure of the Aral Basin can be traced back to the late Neogene, the Sea has only existed in its present form for the past 8–10 ka and the Holocene history has been shaped by regional climatic variations, the development of the associated drainage system and anthropogenic forces. Past hydrological changes in the Aral Basin have led to systematic shifts in the level of the Aral Sea which are reflected sedimentologically through the deposition of `transgressive’ and `regressive’ sedimentary units and geomorphologically through the development of terraces. All the above data are integrated to produced a Late Quaternary history of this important water body.

Holocene sediments of the north Norfolk coast (NNC) between Weybourne and Hunstanton have been studied using geophysical, sedimentological, biofacial and dating techniques. New cores and refraction seismic data have defined the topography of the pre-Holocene surface and show that the NNC sediment prism is underlain by an east-west trending Quaternary trough, probably a palaeo-river-valley. The age of the Holocene fill has been dated using radiocarbon and luminescence dates, while sedimentation rates were constrained by, and compared with, modern rates using radionuclide data. The Holocene sediments are divided into a sandy-barrier lithofacies association (LFA), and a muddy-silty-peat back-barrier LFA. The oldest Holocene sediments are peats, formed on an undulating till surface. These peats were forming by 11-10 cal. ka bp and continued to form until at least 7 cal. ka bp in a number of places. As Holocene sea-level rose, marine mudflat and saltmarsh environments began to form between 7 and 6 cal. ka bp east of Holkham and around 6 cal. ka bp or younger west of Holkham. A marked erosion surface between the barrier and back-barrier LFA in the Holkham to Burnham Overy area is imperfectly dated at

Cainozoic deep-sea ostracod assemblages from the summits of Mid-Pacific guyots point to high levels of endemism possibly as a result of their bathymetric separation from the surrounding sea floor. However, the interpretation of these fossil assemblages is hampered by the paucity of comparative material from surrounding non-guyot sites. Fifteen ostracod assemblages from DSDP Site 463 (Late Cretaceous-Pleistocene) were studied to compare with those from nearby guyots. Three distinct faunal assemblages are recognised at Site 463: Assemblage A (Maastrichtian-Eocene), Assemblage B (Oligocene-Upper Miocene) and Assemblage C (Upper Miocene-Pleistocene) although the palaeoenvironmental significance of these units is unclear. Sixty-two ostracod species are identified, the thirteen most abundant are discussed in the taxonomic section, five of which are described as new. Between 30 and 100% of the species encountered in each sample are considered as endemic to Site 463, while some of the remaining species were previously thought to be endemic to individual guyots. Similarly high levels of endemism on nearby guyots probably reflect an incomplete knowledge of deep-sea ostracod faunas rather than the establishment of geographically or bathymetrically restricted populations. The presence of globally pandemic and geographically widespread taxa on sites such as the Mid-Pacific Mountains, surrounded by abyssal depths which lie below the CCD, indicates that some faunal exchange or migration of ostracods does take place. This must be achieved within the intermediate waters and probably occurs passively.

Early to Middle Jurassic marine ostracod assemblages from the southwestern part of the British Isles, North African continental margin and South America have yielded taxa which are not known from other parts of Britain and Europe. We discuss the palaeogeographical and stratigraphical distribution of these taxa, here arranged into ten informal “groups”, from which we infer that benthonic podocopid Ostracoda successfully migrated between Northwest Europe and the eastern part of Tethys during the Early and Middle Jurassic, not through the main Tethyan seaway but via a proto Atlantic-Central America route supporting previous observations based on macrofossil evidence (“Hispanic Corridor” of Smith, 1983). Furthermore, the fact that these taxa are absent from contemporary European sequences suggests the existence of physical and/or chemical barriers limiting benthonic faunal exchange between the western part of the British Isles and the rest of north-western Europe, particularly during the Late Pliensbachian through to Aalenian interval.

Fluctuations in the level and chemistry during its history have played a major part in shaping the floral and faunal communities of the Aral Sea. Of the eleven species of Ostracoda (Crustacea) known to have been living in the Aral Sea in 1960, only one survives today due to the anthropogenically induced salinity increase of the past three decades. The origins of a mixed fresh- and brackish-water ostracod fauna are discussed, and it is concluded that some of the major faunal elements must have reached the Aral Sea Basin during a past high water level phase when connection existed with the Caspian Sea. The taxonomic position of key taxa is clarified, and the major elements of the pre-1960 Aral Sea ostracod fauna are illustrated from Holocene sequences.Aral Sea, Ostracoda, Holocene, palaeolimnology.

Background Riparian habitats are subjected to frequent inundation (flooding) and are characterised by food webs that exhibit variability in aquatic/terrestrial subsidies across the ecotone. The strength of this subsidy in active riparian floodplains is thought to underpin local biodiversity. Terrestrial invertebrates dominate the fauna, exhibiting traits that allow exploitation of variable aquatic subsidies while reducing inundation pressures, leading to inter-species micro-spatial positioning. The effect these strategies have on prey selection is not known. This study hypothesised that plasticity in prey choice from either aquatic or terrestrial sources is an important trait linked to inundation tolerance and avoidance. Method/Principal Findings We used hydrological, isotopic and habitat analyses to investigate the diet of riparian Coleoptera in relation to inundation risk and relative spatial positioning in the floodplain. The study examined patch scale and longitudinal changes in utilisation of the aquatic subsidy according to species traits. Prey sourced from terrestrial or emerging/stranded aquatic invertebrates varied in relation to traits for inundation avoidance or tolerance strategies. Traits that favoured rapid dispersal corresponded with highest proportions of aquatic prey, with behavioural traits further predicting uptake. Less able dispersers showed minimal use of aquatic subsidy and switched to a terrestrial diet under moderate inundation pressures. All trait groups showed a seasonal shift in diet towards terrestrial prey in the early spring. Prey selection became exaggerated towards aquatic prey in downstream samples. Conclusions/Significance Our results suggest that partitioning of resources and habitat creates overlapping niches that increase the processing of external subsidies in riparian habitats. By demonstrating functional complexity, this work advances understanding of floodplain ecosystem processes and highlights the importance of hydrological variability. With an increasing interest in reconnecting rivers to their floodplains, these invertebrates represent a key functional element in ensuring that such reconnections have demonstrable ecological value.

The late Quaternary to Recent Ostracoda of the Ponto-Caspian region, defined here as the Aral, Caspian and Black seas, play a fundamental role in our understanding of the geological and hydrological evolution of these three large water bodies. Together with sedimentological and geochemical records, the ostracods provide evidence for both natural (climate-influenced) and man-made environmental change. All three seas possess ostracod faunas that are closely related, the Caspian and Black Sea elements are probably isolated remnants of the late Neogene Paratethys fauna while the Aral Sea comprises a much younger fauna introduced from the basins to the east.

We review the utility of ostracods for palaeoclimatic reconstruction at different taxonomic levels. Ostracods can provide palaeoenvironmental information based on several approaches. The chemical and isotopic composition of their mineral shells as well as the relatively minor organic component trapped within the carbonate lattice may give direct quantitative evidence of conditions in their natural habitat. Morphological observations and detailed morphometric records of valve size, shape and outline within a species may provide subtle clues to environmental changes between different habitats or adjacent stratigraphic intervals. Uniformitarian approaches can be applied to species, genera and supra-generic classifications but with decreasing resolution and increasing uncertainty in palaeoenvironmental significance (1) the higher the taxonomic unit and (2) the older the material geologically. The classical methodology of combining the habitat and environmental preferences of individual species to infer palaeoclimatic conditions remains as valid today as when such observations were first made in the nineteenth century.

A core, recovered from a water depth of 53 m in Loch Assynt, North-West Scotland, has yielded a 9 m sequence comprising two distinct units, an upper, organic-rich unit (Unit I, ca. 6 m) overlying a sequence of laminated clays, silts and sands (Unit II, ca. 3 m). The upper unit is essentially Holocene in age based upon three bulk AMS radiocarbon dates while a fourth radiocarbon date from Unit II confirms a late-glacial age for that interval and supports a broadly linear age–depth relationship. Distinct variations in the magnetic susceptibility record of the lower unit can be visually correlated to major changes in the Greenland ice core (GISP2), this together with pollen evidence supports the radiocarbon dating suggesting an age of approximately 11,000 to around 17,000 cal. BP for Unit II, with evidence for the Younger Dryas (Loch Lomond) stadial and the Bolling–Allerod climatic phases. Variations in the magnetic susceptibility record of the late-glacial sediments are thought to relate to climatically driven changes in soil cover and erosion rates. The multiproxy record from Loch Assynt indicates relatively continuous, sub-aqueous sedimentation during the last ∼17,000 years, providing an approximate age for the initiation of modern Loch Assynt and supporting recent dates of moraine retreat lines in the Loanan Valley from about 14–15 ka BP. Pollen and chironomid sampling provides further insights to the history of this relatively deep water body and compliment existing high-resolution palaeo-precipitation records for the mid to late Holocene interval from speleothem archives within the loch catchment.

The Aral Sea is a large terminal lake, i.e. having no outflow, in south-western Asia. It is diminishing in size and the salinity of the water is increasing due to excessive withdrawal of water for irrigation from the two main rivers flowing into it. The biota of the lake has been decimated and the chemical composition changed dramatically since 1960. Three short sediment profiles, two cores and one section, are examined with a view to reconstructing the most recent history of the Sea from microfossil assemblages. Historical and geological records indicate that since its formation Aral Sea levels have changed. Such variation may have been accompanied by changes in the chemistry of the Sea through increased evaporation or precipitation. In the present work analyses of the Mg/Ca and Sr/Ca molar ratios, particularly the latter, of benthonic Ostracoda from the aforementioned cores indicate that although present salinity levels were never attained during the period of deposition of the sections studied past saalinity variation can be inferred. Oxygen and carbon isotope analyses of Ostracoda and Mollusca from one of the sections, however, indicates two possible periods of relative salinity increase.

The foraminiferal and ostracod faunas from two East Anglian, Holocene cores are described. Together they add further environmental evidence to the lithological alternation between peat and alluvial mud sedimentation observed in these sections resulting from local changes in sea-level. Sedimentological and micro-faunal differences between the two sections reflect their relative positions in the estuary with respect to the local palaeogeography. Foraminifera are abundant, the Ostracoda less so, nevertheless a comprehensive environmental interpretation is given and a foraminiferal ecological zonation proposed. Palaeoenvironmental reconstructions are based upon both microfossil groups which complement each other.

Surface sediments, water samples and environmental data from 37 lakes, ponds and streams in Israel were analysed to determine the main variables controlling ostracod species distributions. Multivariate statistical analysis revealed that the greatest amounts of variation in the distribution of the ostracod taxa among the 37 water bodies were explained by the host water δD value (12.9%), water temperature (11.0%), mean January air temperature (10.5%), electrical conductivity (9.5%), and the Mg and NO3 concentrations (7.8 and 7.1%, ion concentrations as % of the anions or cations). A supplementary data set comprising ostracod species composition and electrical conductivity readings for 24 water bodies was available from previous research and was merged with the 37 samples data set to develop an ostracod-based transfer function for the reconstruction of electrical conductivities. A weighted averaging partial least squares regression (WA-PLS) provided the best results with a relatively high coefficient of determination (r 2) between measured and inferred electrical conductivity values of 0.73, a root mean square error of prediction of 0.13 (13.4% of gradient length) and a maximum bias of 0.24 (23.9% of gradient length), as assessed by leave-one-out cross-validation based on 56 water bodies. The application of the EC transfer function onto (sub)fossil ostracod assemblages from Holocene and early to mid Pleistocene lake sediments provided EC values consistent with other proxies and demonstrated that Quaternary ostracod assemblages from subaqueous sediments can now be used to trace the hydrological history of water bodies in the Near East. A better understanding of past hydrological conditions in response to the natural climate variability is crucial in regions that face restricted water resources and rising demands in times of rapid climate and environmental change.

The Ostracoda are a subclass of small Crustacea which inhabit most aquatic environments; they have been recorded from the Cambrian through to the Recent. The biology of one group of marine Ostracoda, the Platycopina (Triassic-Recent), enables them to better withstand decreased levels of dissolved oxygen, in their immediate environment, than other ostracods. Study of a number of geological sections has already shown that this suborder often dominates stratigraphical intervals which are considered to be representative of dysaerobic conditions. In the light of this work the changing faunal composition of the Lower Jurassic of the Mochras Borehole, Wales is interpreted as a series of environmental changes which include fluctuating oxygen levels. The degree of dysaerobia is assessed and its effect on the rate of faunal turnover is discussed.

The extensive Lower Jurassic sequence at Mochras has yielded a diverse ostracod fauna which includes many new taxa. Poor preservation precludes a complete taxonomic review of this material although four new species (Cytherella praetoarcensis, Ogmoconcha convexa, Lophodentina striata and Oligocythereis? mochrasensis) are erected herein. Changes in the faunal composition and the rates of faunal turnover are briefly described. An ostracod biozonation is proposed for the section, comparison with established Lower Jurassic zonal schemes reveals that the present section is distinct from most other European sequences.

Ostracod species diversity in marginal marine environments is markedly lower than in non- and fully marine ecosystems. This largely reflects the physiological burden encountered during diurnal tidal cycle (e.g. salinity changes). These environments encompass not only the open-marine systems but also settings that undergo marked environmental variability over a range of timescales. The abundance of individuals in marginal marine environments can reach very high levels resulting in near monospecific faunas of specialised taxa. The ostracods must tolerate varying parameters such as salinity, temperature and dissolved oxygen levels over a range of temporal scales and even short periods of exposure. Given the often poor preservation potential of organisms in marginal marine environments there may appear to be limited potential for ostracods in Quaternary research, however, in this work we review the utility of these organisms in reconstructing past sea-levels and salinity regimes in marginal marine settings, based on criteria such as sieve-pore shape, noding, shell size and shell chemistry. In the following pages we outline the range of modern environments from which marginal marine ostracods have been investigated, discuss their preservation potential and illustrate (where possible) examples of similar environments from Quaternary deposits. Subsequently we discuss the reconstruction of past marginal marine environments from individual specimens, particular species or a fossil assemblage. Finally, we give two case studies of the use of ostracods in reconstructing past marginal marine environments from Holocene sediments in Norfolk, eastern England and from Menorca, Balearic Islands in the Mediterranean.

Ostracodes are mainly benthic Crustacea. They are commonly preserved in marine and marginal marine sediments and are used increasingly in Quaternary paleoceanography. The ecological sensitivity of ostracode species to temperature, salinity and dissolved oxygen have allowed paleoceanographic reconstruction of important climate-related variables over timescales ranging from 10 7 to 10 2 years. This chapter reviews recent advances in the application of ostracodes to the study of large-scale ocean and climate events caused by Cenozoic tectonic and climate changes with particular reference to Quaternary orbital forcing, thermohaline circulation, decadal and interannual (El Nino-Southern Oscillation) climate variability, and 20 th century anthropogenic factors.

Pliensbachian and Toarcian Ostracoda first described by Exton (Geological Paper, Carleton University, Ottawa, 79: 1–104 1979) from the Lusitanian Basin, west-central Portugal have been re-examined. As a result, a greater diversity in the Ostracoda (80 species) is now recognized. Two species are newly described (Eucytherura zambujalensis sp. nov., Ektyphocythere mediodepressa sp. nov.) from the marls and calcareous shales of the Maria Pares Hill section near the village of Zambujal. Poor preservation precludes a complete taxonomic review of the present material. Five ostracod zones are proposed; Gammacythere ubiquita–Ogmoconchella gruendeli Zone, Poly cope cerasia–Polycope cincinnata Zone, Liasina lanceolata–Ogmoconcha convexa Zone, Bairdiacypris rectangularis–Kinkelinella sermoisensis Zone, and Cytherella toarcensis-Kinkelinella costata Zone. Although the ostracod assemblages possess strong similarities to those described from Northwest Europe, some of the Zambujal assemblages are dominated by the genus Polycope. A marked faunal turnover, in association with the extinction of the Metacopina occurs in the lower Subzone of the tenuicostatum Zone of Lower Toarcian age. These faunal events are discussed in relation to changing environmental conditions.

The avian embryo resorbs most of the calcium for bone formation from the calcite eggshell but the exact mechanisms of the resorption are unknown. The present study tested whether this process results in variable fractionation of the oxygen and carbon isotopes in shell calcium carbonate, which could provide a detailed insight into the temporal and spatial use of the eggshell by the developing embryo. Despite the uncertainty regarding changes in stable isotope composition of the eggshell across developmental stages or regions of the shell, eggshells are a popular resource for the analysis of historic and extant trophic relationships. To clarify how the stable isotope composition varies with embryonic development, the δ13C and δ18O content of the carbonate fraction in shells of black-headed gull (Larus ridibundus) eggs were sampled at four different stages of embryonic development and at five eggshell regions. No consistent relationship between the stable isotope composition of the eggshell and embryonic development, shell region or maculation was observed, although shell thickness decreased with development in all shell regions. By contrast, individual eggs differed significantly in isotope composition. These results establish that eggshells can be used to investigate a species’ carbon and oxygen sources, regardless of the egg’s developmental stage.

The extinction of the Suborder Metacopina in the early Toarcian (Early Jurassic) was a major event in the macro-evolutionary history of the Ostracoda. The disappearance of this long-ranging, essentially Palaeozoic, group coincides with a change in the composition of marine ostracod faunas from ones with residual Palaeozoic aspect in the pre-Toarcian (due to the presence of the Metacopina) to those dominated by the Cytheroidea, Cypridoidea and Platycopina, a pattern that continues to the present. The Metacopina had been present in many Palaeozoic assemblages although usually at low diversity and abundance but they were particularly successful in Triassic and Early Jurassic times, being diverse, abundant and with an apparently cosmopolitan distribution. Why did such a successful group that had survived four of the ’Big Five’ Phanerozoic extinction events (end Ordovician, Late Devonian, end-Permian, end-Triassic), succumb at this second order and apparently less significant early Toarcian event? The rapid decline and extinction of the Metacopina followed a major regressive phase in the Pliensbachian and broadly coincided with the onset of the early Toarcian Oceanic Anoxic Event (TOAE), which has been linked to global eustatic sea-level rise and is marked by a major, negative carbon isotope (δ13C ) excursion in the global carbon cycle. The nature and likely causes of the Metacopina extinction event (MEE) are reviewed in the context of new environmental data for the Toarcian, with particular reference to evidence from the Mochras Borehole (West Wales) ; the group’s survival of earlier biotic events is also discussed. The one distinct feature that sets the Toarcian extinction event apart from previous evolutionary crises is that the Metacopina never had to compete against relatively advanced ostracod, largely cytheroidean, taxa that were present during the Early Jurassic. We propose that this may have been a key factor in the demise of the Metacopina at this particular time.

INTRODUCTION (F. JOHN GREGORY)To commemorate the publication of the 25th Volume of the Journal of Micropalaeontology, the first issue of which came out in 1982, this celebratory review article was commissioned. Officers of each TMS Group (Ostracod, Foraminifera, Palynology, Nannofossil, Microvertebrate and Silicofossil) were requested to reflect over the last 25 years and assess the major advances and innovations in each of their disciplines. It is obvious from the presentations that all Groups report that research has moved on from the basic, but essential descriptive phase, i.e. taxonomy and establishing biostratigraphies, to the utilization of new technologies and application to issues of the day such as climate change and global warming. However, we must not lose sight of the fact that the foundation of micropalaeontology is observation and the building block for all these new and exciting innovations and developments is still good taxonomy. Briefly, the most obvious conclusion that can be drawn from this review is that micropalaeontology as a science is in relatively good health, but we have to ensure that the reported advancements will sustain and progress our discipline. There is one issue that has not really been highlighted in these contributions – we need to make sure that there are enough people being trained in micropalaeontology to maintain development. The last 25 years has seen a dramatic decrease in the number of post-graduate MSc courses in micropalaeontology. For example, in the UK, in the 1980s and early 1990s there were five specific MSc courses to choose . . .

Blakeney Spit extends more than 12 km along the North Norfolk coast, from its origin near Weyboume in the east, to a location opposite a point halfway between Morston and Stiffkey in the west. Borehole investigations landward of the spit have revealed remarkably uniform sequences of intertidal sediments, sometimes passing from lower intertidal muds into upper intertidal saltmarsh, sometimes being rather uniform upper saltmarsh throughout. Similar intertidal sediments are found landward of an inter-tidal barrier extending from off Stiffkey to off Wells. The thickness of these deposits, resting either on glacial deposits or directly on Chalk, reaches over 15 m in places, along the line of an original E-W trough or channel. Adequate radiocarbon and other reliable dating of these deposits has proved somewhat difficult to determine, but the earliest are Post-Glacial non-marine deposits as old as 10 000 years bp , with the initiation of marine deposition at c . 7500-6500 years bp at the eastern end of the sector. Apart from the Stiffkey and Morston mainly gravel and sandy ‘Meals’ barriers, which are resting on top of saltmarsh deposits and probably date back to no more than 670-900 years bp , there are no other sand or shingle deposits, except in drainage channels, anywhere landward of Blakeney Spit. The spit itself is being produced by the erosion of the cliffs east of Weybourne, and the entire Holocene and glacial sequences on its seaward side, rolling the sand and shingle body over landward (at about 1 m per annum), and prograding westward, (at c . 3.5 m per annum) - as indicated by accurate maps constructed over the last 400 years.

We examined trends in the movement and source of water in a headwater wetland in North Shropshire, UK. Six piezometer nests along two transects were monitored over an 18 month period, and flownets were derived to estimate the rate and direction of water movement through the wetland and the interaction between precipitation and groundwater discharge. Individual water sources are identified using stable isotopes and seasonal differences in the composition of wetland soil-water are described. Variations in dissolved inorganic and organic carbon (DIC and DOC) were measured in water samples collected from discrete points in the wetland and the adjacent river and were interpreted using the hydrological data. The results suggest that end-members for DOC and DIC can be identified across the range of sampling sites: a groundwater spring (GS) had the lowest DOC and high DIC (DOC = 5.6 ± 4.5 mg/l; DIC = 36.7 ± 4.6 mg/l); a shallow well (WS) had the highest DOC and DIC (DOC = 32.5 ± 18.7 mg/l; DIC = 61.9 ± 18.9 mg/l); while surface-water (WSW) had the lowest DIC (20.6 ± 12.1 mg/l). Water fluxes between the wetland and river are estimated using the Dupuit-Forcheimer approximation to highlight the degree to which some headwater wetlands may act as a carbon source to ecosystems downstream. These wetlands are potentially a significant pool of C but are particularly sensitive to future changes in groundwater levels.