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This paper reviews the implications of climate change for the water environment and its management in England. There is a large literature, but most studies have looked at flow volumes or nutrients and none have considered explicitly the implications of climate change for the delivery of water management objectives. Studies have been undertaken in a small number of locations. Studies have used observations from the past to infer future changes, and have used numerical simulation models with climate change scenarios. The literature indicates that climate change poses risks to the delivery of water management objectives, but that these risks depend on local catchment and water body conditions. Climate change affects the status of water bodies, and it affects the effectiveness of measures to manage the water environment and meet policy objectives. The future impact of climate change on the water environment and its management is uncertain. Impacts are dependent on changes in the duration of dry spells and frequency of ‘flushing’ events, which are highly uncertain and not included in current climate scenarios. There is a good qualitative understanding of ways in which systems may change, but interactions between components of the water environment are poorly understood. Predictive models are only available for some components, and model parametric and structural uncertainty has not been evaluated. The impacts of climate change depend on other pressures on the water environment in a catchment, and also on the management interventions that are undertaken to achieve water management objectives. The paper has also developed a series of consistent conceptual models describing the implications of climate change for pressures on the water environment, based around the source-pathway-receptor concept. They provide a framework for a systematic assessment across catchments and pressures of the implications of climate change for the water environment and its management. [ABSTRACT FROM AUTHOR]

Pollen analysis of a 48 m AMS radiocarbon-dated sediment sequence from the Guadiana estuary provides the first record of Lateglacial and Holocene vegetation history in the Algarve province of Portugal. This paper focuses on the record of terrestrial pollen taxa, which document a series of forest expansions and declines during the period 13 000 cal. BP to 1600 cal. BP and provide insights into climate evolution in southwestern Iberia. The main vegetation phases identified in the Guadiana valley are (1) Lateglacial interstadial (Allerød) forest with Quercus and Pinus under a temperate, moist, continental climate; (2) a Younger Dryas forest decline (Quercus) and expansion of pinewoods, xeric scrub and open ground habitats (with Juniperus, Artemisia, Ephedra distachya type, Centaurea scabiosa type) under arid and cold conditions; (3) an early Holocene forest/scrub/open-ground vegetation mosaic developing under a warm, dry and continental climate; (4) a maximum of Quercus forest and thermomediterranean evergreen taxa (Olea, Phillyrea, Pistacia) reflecting a warm, moist oceanic climate between c. 9000 cal. BP and c. 5000 cal. BP; and (5) the expansion of shrublands with Cistaceae and Ericaceae under a drier climatic regime and increasing anthropogenic activity since c. 5000 cal. BP. Holocene episodes of maximum climatic aridity are identified in the record of xerophytic taxa (Juniperus, Artemisia, Ephedra distachya type) centred around 10 200 cal. BP, 7800 cal. BP, 4800 cal. BP, 3100 cal. BP and 1700 cal. BP. Regional comparisons suggest a correlation of arid phases across southern Iberia and northwest Africa, which can be related to abrupt North Atlantic coolings (Bond events). [ABSTRACT FROM AUTHOR]

In this paper, we reconstruct the Holocene paleoenvironmental evolution of the Guadiana Estuary, southwestern Iberian Peninsula. Two previously studied boreholes (CM3 and CM5) were revisited and analyzed in the light of a foraminifera modern analog approach. Cluster analyses define four assemblages with different biocenotic, taphonomic, elevation and distance-to-sea settings, which serve as a baseline for paleoassemblages interpretation. Faunal changes along the sedimentary sequences, together with previous sedimentological and chronological data, redefine the different phases of environmental evolution in the Guadiana Estuary since ca. 13 kyr cal. BP, with special emphasis on the Holocene marine highstand. Estuarine flooding began synchronously in both locations (ca. 9 kyr cal. BP) but manifested differently in each sedimentary sequence. The most seaward borehole records a more evident and longer highstand (ca. 8.8-3.8 kyr cal. BP), characterized by the occurrence of subtidal environments and by the presence of open marine species (Pararotalia cf. spinigera, planktic forms and a significant number of exotic/allochthonous tests), indicating warmer and more marine conditions than today. In the most landward borehole, the highstand is shorter (ca. 8-7.6 kyr cal. BP) and less intense, characterized by the presence of a diverse, mainly autochthonous, open estuary assemblage, dominated by Ammonia aberdoveyensis and Haynesina germanica. At 4.4 kyr cal. BP, during a long deceleration phase of regional sea-level rise, a short but well-defined pulse of marine influence is recorded in CM5, when open estuarine assemblages reappear and replace marsh agglutinated assemblages, suggesting a new submergence phase. This short event is not identified in the previous works carried out in the same area, thus further data are needed to understand whether it is consequent from a global, warming period or whether it resulted only from local and ephemeral forcing effects. [ABSTRACT FROM AUTHOR]

Recent research on climate vulnerability in cities in the Amazon Delta and Estuary (ADE) shows that about 1.2 million people are at risk of flooding due to the rapid unplanned occupation of lowlands and the absence of investment in infrastructure and services. In this study, we use secondary climate and census data, interviews and focus groups in four small cities in the Amazon Delta and Estuary (SCADEs), to discuss how residents and local governments perceive and respond to climate hazards and their implications. These SCADEs may be better equipped than other urban areas to deal with challenges brought by climate change, due partially to residents' high mobility between urban and rural areas and a tradition of adaptive actions in a dynamic social and environmental context. However, persistent flooding and sinkholes demonstrate the limited capacity of local governments to cope with the dynamics of accelerated occupation of floodplain areas in SCADEs. [ABSTRACT FROM AUTHOR]

Multidisciplinary paleoproxy data from three sedimentary cores (9.05-m-long MW-2, 16.50-m-long IL-3, and 11.88-m-long JD-1) recovered from the Yeongsan River Estuary of Korea are presented. A marine influence can be observed at 10,400 yr BP (−21 m) and 8600 yr BP (−14 to −12 m) around the Yeongsan River Estuary. However, if we take the macro-tidal setting of the Yeongsan River Estuary into consideration, actual sea level could differ from the depositional surfaces, and might be higher or lower than the sediment elevation. Precipitation at around 6300–5000 yr BP is estimated to have been higher or stronger than in earlier and later periods. The core sites received increased terrigenous sediment input during this period because of intensified rainfall and consequent river activity. Although sea level was estimated to be high enough to have a strong influence on the study area during the mid-Holocene, the sedimentary features suggest that riverine activity was the dominant factor controlling the sedimentation patterns. This implies that even during the Holocene Climate Optimum in Korea, roughly 7000–5000 yr BP, the wetter condition has occurred within the interval of 6300–5000 yr BP. After the Holocene Climate Optimum, sea level decreased to 0 to −1 m around 5000 yr BP and increased again starting around 4000 yr BP. The time-series results presented in this study are coincident with global trends, and show the potential for developing geomorphological and climate histories for this region. [ABSTRACT FROM AUTHOR]

Analyses of pollen, plant macrofossils (seeds, fruits, wood and mosses), molluscs, diatoms and vertebrate (mainly fish) remains allowed a detailed reconstruction of a middle-Holocene alluvial forest and its associated hydrological conditions. The use of multiple proxies resulted in a taxonomically more detailed and environmentally more comprehensive understanding of terrestrial as well as aquatic habitats. The results demonstrate possible biases in palaeoecological reconstructions of alluvial and estuarine environments drawn from single proxies. Many locally occurring woody taxa were underrepresented or remained undetected by pollen analyses. Seeds and fruits also proved to be inadequate to detect several locally important taxa, such as Ulmus and Hedera helix. Apparently brackish conditions inferred from diatoms, pollen and other microfossils conflicted strikingly with the evidence from molluscs, fish bones and botanical macroremains which suggest a freshwater environment. Brackish sediment (and the microfossil indicators) is likely to have been deposited during spring tides or storm surges, when estuarine waters penetrated more inland than usual. Despite the reworking and deposition of estuarine and saltmarsh sediment well above the tidal node at such events, local salinity levels largely remained unaffected. [ABSTRACT FROM PUBLISHER]

Climate change poses many challenges for the future management and development of the coastal zone. Uncertainties in the rate of future sea-level rise reduce our ability to project potential future impacts. This study seeks to further develop the past–present–future methodology proposed in Baker and McGowan and apply it to an additional case study, the Macleay River estuary, New South Wales (NSW), Australia. The past–present–future methodology uses evidence from the past, the Holocene and Pleistocene, to formulate a response function that can be used to project future sea-level heights. Three scenarios for 2100 were developed to emphasise the uncertainties surrounding future sea levels and the need to consider multiple sea-level rise scenarios when planning for the future: a best case (90 cm rise), mid-case (2.6 m rise) and worst case (5 m rise). Light detection and ranging (LiDAR) data were used to project each of the three scenarios onto the case study area of South West Rocks. The methodology was tested by using shell samples extracted from cores which were AMS dated to determine whether or not Holocene estuarine conditions correlated with the proposed future sea-level rise inundation scenarios. We also conducted an audit of potentially affected infrastructure and land uses, and proposed possible future adaptation strategies for the case study area. [ABSTRACT FROM PUBLISHER]

The southeastern coastal plain of Sri Lanka contains Holocene sediment archives representing the winter monsoon variability because this region is protected from both summer monsoon and cyclonic rainfall. Chemical, biological, mineralogical, and physical climate proxies were studied in sediment cores extracted from three different coastal estuaries and lagoons situated on the southeastern coast to derive winter monsoon variability. These cores displayed minimum influence of sea level-related changes in sediments. Clay normalized proxy records suggest intervals of aridity from >7300 to ~6750, semi-aridity from ~6250 to 4600 yr BP, and aridity from ~4000 to 3000 and ~1100 to <500 cal. yr BP, with a short wet interval from ~6500 to 6250 cal. yr BP, and a wet interval from ~3000 to 1500 yr BP. Our results match the timing of previously published climate events for Holocene variations in the Indian summer monsoon. Wavelet analysis of the detrended climate proxy records identify significant periodicities at: ~20 ~28–32, ~64, ~100, ~128, ~192, ~256 yr in our data. Most of these periodicities are consistent with known solar irradiance cycles, which drive the decadal- to centennial-scale variability of the summer monsoon. Our multiproxy record for mid- to late-Holocene climate in southeastern Sri Lanka documents that Indian winter monsoon variability is statistically similar to Indian summer monsoon variability, suggesting similar forcing mechanisms. [ABSTRACT FROM AUTHOR]

Mollusks recovered from three cores taken from the Cananéia-Iguape estuarine-lagoonal system (São Paulo State, Brazil) were studied. The sampled sediments cover a period beginning approximately two centuries ago and end at the present, including a period when the system suffered significant changes of anthropogenic origin – that is, the construction of an artificial channel connecting the lagoon with a nearby river and with the resulting input of fresh water and contaminants generated from mining activity upstream. The mollusk composition reflects these changes. The more abrupt changes in this composition coincide with the opening of the Valo Grande artificial channel in 1852. Another significant but minor change event was verified for around 1977± one year in areas that were not previously affected, perhaps showing the effect of the closing and reopening of the channel. [ABSTRACT FROM AUTHOR]

The absence of accurate sea-level index points in SW Europe has long precluded the development of Holocene sea-level curves and the correct understanding of tectonic activity. In order to understand the coastal evolution and the major drivers in the Minho area, Portugal, we have combined micropaleontological and sedimentological data, where the chronological framework is provided by 13 radiocarbon ages. The stratigraphic reconstruction is in agreement with regional models of evolution and provides new sea-level index points that support a regional isostatic model producing the first complete Holocene sea-level curve from this area. Field data and model reconstructions present a good agreement for the region considered and vertical land movement estimates derived from the isostatic model are in agreement with GPS vertical velocities. At regional scale, our results support a north–south trend for SW Europe, where isostatic rebound seems to be minimized in the south of the Iberian Peninsula while local factors (sedimentation, local geomorphology, etc.) tend to dominate during the late Holocene. This newly produced sea-level curve has helped to improve isostatic model predictions and provide pre-anthropogenic sea-level rise rates against which modern rates can be compared. [ABSTRACT FROM AUTHOR]

Assemblages of benthic foraminifera in a Holocene core from the outer area of Bahía Blanca estuary in Argentina were studied. The systematic of the group was updated, and provided 28 genera distributed among 59 species, six species with nomenclature aperta. The main species recorded were Buccella peruviana f. campsi (Boltovskoy), Ammonia beccarii (Linné), Elphidium gunteri Cole, Elphidium galvestonense Kornfeld, Elphidium articulatum d'Orbigny and Elphidium discoidale (d'Orbigny). These species allowed an estuarine environment to be determined. Qualitative and quantitative studies conducted on the faunistic content in the core allowed identification of three subenvironments closely linked to sea-level fluctuations during the mid Holocene: a lower zone (6350 yr BP) corresponding to a high intertidal environment, an intermediate zone (2460 yr BP) representing a low intertidal environment related to a system of channels and variations in environmental energy, and an upper zone characterized by the development of a high-energy littoral environment affected by the action of waves, tides and tidal currents, which underwent progressive change until it attained present-day conditions. [ABSTRACT FROM AUTHOR]

This review highlights recent work in coastal geomorphology that challenges existing wisdom, breaks new ground or contributes in some way to wider principles. Sediment transport by currents and by waves remains a major focus of coastal process geomorphology, and the contribution of this work to our appreciation of landform dynamics is particularly evident at the beach scale. Reconstructive studies over Holocene to historical timescales are yielding new insights into the adjustment of coastal sedimentary systems to progressive environmental forcing, high-magnitude events and human activities. Coastal geomorphology is currently buoyed by opportunities afforded by the implied threats of climate change and sea-level rise, and by the conceptual and technical challenges of predicting morphodynamic behaviour at the all-important 'engineering' scales. Of some concern is the lack of dialogue with other major strands of geomorphology. One of the main challenges, to create models capable of revealing emergent aspects of spatially distributed interactions between form and process, is common to all geomorphologists engaged with the meso-scale. Yet coastal specialists seem reluctant both to draw inspiration from and also to contribute ideas to what might be seen as a single, extremely broad, research front. More generally, there is little exchange of ideas or contribution to a shared intellectual endeavour. Coastal geomorphology is at the forefront of the discipline when it comes to the exploitation of new environmental instrumentation and remote sensing technologies. It can only be hoped that the plethora of high-resolution multitemporal data sets will contribute to the advance of geomorphological thinking rather than merely being used to constrain sediment budgets as a basis for the management of localized erosion problems. [ABSTRACT FROM AUTHOR]

The recent growth in the use of microfossil-based transfer functions in late-Quaternary sea-level reconstructions reflects their potential to accurately quantify palaeo sea-level changes. This study details the development of a diatom-based sea-level transfer function for the Severn Estuary, southwest England, a macrotidal setting that experiences the second highest tidal range in the world. This setting presents difficulties in representing the full tidal range from mean sea level (MSL) to highest astronomical tide (HAT). However, two separate transects were merged successfully and a statistically significant relationship between contemporary diatom assemblages and altitude (m O.D.) was established. A diatom-based transfer function for palaeoaltitude was developed using weighted averaging (WA), tolerance downweighted weighted averaging (WA-Tol) and weighted averaging partial least squares (WA-PLS). WA-Tol produced the lowest prediction errors for altitude and the transfer function was applied to a fossil diatom data set from Gordano Valley, a site adjacent to the Severn Estuary. [ABSTRACT FROM AUTHOR]

Coastal and marine sedimentary archives are sometimes used as indicators of changes in continental sediment production and fluvial sediment transport, but rivers crossing coastal plains may not be efficient conveyors of sediment to the coast. Where this is the case, changes in continental sediment dynamics are not evident at the river mouth. Stream power is typically low and accommodation space high in coastal plain river reaches, resulting in extensive alluvial storage upstream of estuaries and correspondingly low sediment loads at the river mouth. In some cases there is a net loss of sediment in lower coastal plain reaches, so that sediment input from upstream exceeds yield at the river mouth. The lowermost sediment sampling stations on many rivers are too far upstream of the coast to represent lower coastal plain sediment fluxes, and thus tend to overestimate sediment yields. Sediment which does reach the river mouth is often trapped in estuaries and deltas. Assessment of sediment flux from coastal plain rivers is also confounded by the deceptively simple question of the location of the mouth of the river. On low-gradient coastal plains and shelves, the location of the river mouth may have varied by hundreds of kilometers due to sea-level change. The mouth may also differ substantially according to whether it is defined based on channel morphology, network morphology, hydrographic or hydrochemical criteria, elevation of the channel relative to sea level, or the locus of deposition. Further, while direct continent-to-ocean flux may be very low at current sea-level stands, sediment stored in estuaries and lower coastal plain alluvium (including deltas) may eventually become part of the marine sedimentary package. The role of accommodation space in coastal plain alluvial sediment storage has been emphasized in previous work, but low transport capacity controlled largely by slope is also a crucial factor, as we illustrate with examples from Texas. [ABSTRACT FROM AUTHOR]

This study employs a multiproxy approach in the reconstruction of Holocene monsoon history from sedimentary sequences obtained from the Pearl River Estuary, southern China. A set of modern surface sediment samples were collected within and outside the estuary, and a sediment core was obtained from the mouth of the estuary. A range of modern environmental variables were recorded including water salinity (summer, winter and annual average) and water depth. The diatom results show a good relationship with water salinity, with marine diatoms dominating the more distal samples from outside the main estuary and freshwater diatoms dominating the proximal samples influenced by higher freshwater flux. This pattern is matched by the bulk organic carbon isotopes. The isotope values vary between -21.1±0.3‰ for samples from the fully marine environment, between -23.2±0.8‰ and -23.7±0.8‰ for samples from the mid to outer estuary brackish water environment and less than -24.7±1.3‰ for samples from the inner estuary close to the freshwater sources. Similarly, the C/N ratios vary from below 7±0.6 in the marine end-members to over 14.8±3.0 in the freshwater end-members. Both the diatom and carbon data from the sediment core reveal a significant increase in freshwater flux from 8500 cal. yr BP resulting from the enhanced summer monsoon regime in early Holocene. The strength of freshwater flux reached its highest between 7500 and 6000 cal. yr BP. In the last 6000 years, freshwater flux decreased towards present, reflecting a gradual weakening of the summer monsoon. [ABSTRACT FROM AUTHOR]

Shores of eastern Hokkaido rose by perhaps 1 m a few centuries ago. The uplifted area extended at least 50 km along the southern Kuril Trench. It included the estuaries Akkeshi-ko and Hichirippu, on the Pacific coast, and Furen-ko and Onneto, which open to the Okhotsk Sea. At each estuary, intertidal and subtidal flats rose with respect to tide level; wetland plants colonized the emerging land; and peaty wetland deposits thereby covered mud and sand of the former flats. Previous work at Akkeshi-ko and Onneto showed that such emergence occurred at least three times in the past 3000 years. Volcanic-ash layers date the youngest emergence to the seventeenth century AD. New evidence from Akkeshi-ko, Hichirippu and Furen-ko clarifies the age and amount of this youngest emergence. Much of it probably dates from the century's middle decades. Some of the newly emerged land remained above high tides into the middle of the eighteenth century or later. The emergence in the last half of the seventeenth century probably exceeded 0.5 m (inferred from stratigraphy and diatom palaeoecology) without far exceeding 1 m (estimated by comparing seventeenth- and eighteenth-century descriptions of Akkeshi-ko). The stratigraphy and palaeoecology of the emergence are better explained by tectonic uplift than by bay-mouth blockage, tidal-flat accretion or sea-level fall. Eastern Hokkaido needs occasional uplift, moreover, to help reconcile its raised marine terraces with its chronic twentieth-century subsidence. Because it took place above forearc mantle, eastern Hokkaido's seventeenth-century uplift probably lacks analogy with coseismic uplift that occurs above typical plate-boundary ruptures at subduction zones. [ABSTRACT FROM AUTHOR]

A high-resolution textural study has been made of laminated and banded estuarine silts exposed intertidally at representative localities and horizons in the Holocene deposits of the Severn Estuary Levels. The laminae, on a submillimetre to millimetre scale, are sharp-based, graded couplets formed of a lower silty part overlain by a finer-textured clayey element. The centimetre- to decimetre-scale banding is formed of laminae in alternating, gradually intergrading sets of relatively coarse and relative fine-grained examples. At outcrop in the field, the banding is recognizable because the coarse sets prove to be recessive to varying degrees under the influence of weathering and current action. Independent evidence at two localities points toward an annual origin for the banding; at a third it arose during part of what appears to have been a relatively short period. Quantified physical arguments suggest that the textural banding is a response of suspended fine sediment to marked seasonal changes in sea temperature and windiness. The banded silts occur in four distinct stratigraphical contexts and record high deposition rates (order 0.01 À 0.1 m = yr). Because physical factors determine their textures, the silts potentially afford insights in all contexts into aspects of changing Holocene climatic conditions. In one context, the thickness of the bands points to high (order 0.01 À 0.1 m = yr) but comparatively short-lived (order 10s À 100s yrs) rates of relative water-level rise. In the others, however, the banding has no implications for sea-level behaviour, and simply records gross environmental disequilibrium, for example, the recovery of mudflats = marshes after an erosional episode. Similarly, because on account of their rapid accumulation the banded silts preserve animal and human tracks and trackways especially well, they provide an archive of animal and human behaviour in the area during the Holocene. [ABSTRACT FROM AUTHOR]

Techniques for estimating tidal elevation and confinement (proxy for salinity) using modern benthic foraminiferal census data from New Zealand harbours and lower-salinity estuaries are described and assessed for their utility for reconstructing the depositional settings of late-Holocene sequences. We describe a simple modern analogue technique for estimating tidal or subtidal elevation of Holocene fossil faunas, utilizing the modern data set most applicable to the Holocene setting (sheltered tidal harbours and inlets, or lower-salinity estuaries). Canonical correspondence analysis was used to extract a synthetic confinement gradient from foraminiferal census data in transects down five New Zealand estuaries. This gradient was used to develop a New Zealand Confinement Index that can be computed for New Zealand modern and Holocene estuarine and harbour samples based on their foraminiferal composition. The value of the method for estimating Holocene elevational and confinement (palaeosalinity) histories was assessed for a tidal inlet and the middle reaches of an estuary. Two earthquake-related vertical displacements are recognized in a 1.1 m core from Ahuriri Inlet, Hawkes Bay: (1) a 1-2 m subsidence (c. 500 BP) from low tidal to subtidal; (2) a 1.5-2.5 m uplift (1931 Napier Earthquake) from subtidal to high tidal, followed by progressively increasing confinement in a much smaller inlet. A substantial confinement increase (probable salinity decrease) is recognized in a 0.8 m core from Rangitopuni Estuary, Auckland, accompanying the widespread disappearance of cockle beds. Palynology shows that this event is associated with forest clearance in the watershed following earliest significant human settlement (c. 600-800 BP). Taphonomic dissolution of calcareous tests was a significant factor in the lesser accuracy of elevational estimates in our estuarine study core, although dissolution appears to correspond with increased freshwater runoff. Taphonomic disaggregation and loss of agglutinated foraminifera did not appear to be significant in these short cores. [ABSTRACT FROM AUTHOR]

Benthic foraminiferal species were used to AMS date Holocene sediments adjacent to trangressive overlap boundaries (TOB) in two high-energy estuaries in northern Spain. It had previously been recognized that the foraminifera could be divided into indigenous and exotic components. Whereas it was known that the exotic forms had been transported into the estuaries from the adjacent inner shelf, it was assumed that the indigenous forms were in situ. The AMS dates based on indigenous forms obtained from pairs of samples adjacent to the TOB showed an inverse relationship in three out of four boreholes (i.e., the age of the higher sample was older than that of the lower). The most probable explanation of this unexpected result is that there had been significant reworking of indigenous foraminifera especially associated with the transgressive episode. It is concluded that, in high energy estuaries, AMS dating on foraminiferal shells is influenced by transport and reworking even of the indigenous component. Therefore, if only foraminifera are available for dating, we recommend that closely spaced pairs of samples should be dated in order to assess the reliability of the results. [ABSTRACT FROM AUTHOR]