An 8000-year multi-proxy peat-based palaeoclimate record from Newfoundland: Evidence of coherent changes in bog surface wetness and ocean circulation

Energy carried by warm tropical water, transported via the Atlantic Meridional Overturning Circulation (AMOC), plays a vital role in regulating the climate of regions bordering the North Atlantic Ocean. Previous phases of elevated freshwater input to areas of North Atlantic Deep Water (NADW) production in the early to mid-Holocene have been linked with slow-downs in the AMOC and changes in regional climate. Newfoundland’s proximity in the North Atlantic region to the confluence of the Gulf Stream and the Labrador Current and to an area of NADW production in the Labrador Sea makes it an ideal testing ground to investigate the influence of past fluctuations in ocean circulation on terrestrial ecosystems. We use multi-proxy peat-based records from the east coast of Newfoundland to derive a proxy-climate signal for the last 8000 years, which we have compared with changes in ocean circulation. Prominent shifts towards near-surface bog water table levels, reflecting cooler/wetter climatic conditions, are evident in the early-mid Holocene c. 7830, 7500, 7220 and 6600 cal. BP with minor changes occurring c. 6340, and 6110 cal. BP. These events are coherent with evidence of meltwater injections into the N. Atlantic and of reduced NADW production. More recent increases in bog surface wetness in the mid-late Holocene c. 4290 and c. 2610 cal. BP are also consistent with reported periods of reduced NADW production. Coherence between the bog-derived palaeoclimate record developed from Newfoundland and evidence of fluctuations in ocean current strength is apparent in the early mid-Holocene

Post glacial history of the Nant Helen opencast site South Wales: implications for land restoration

A proposal to extend opencast mining at Nant Helen Colliery, South Wales, threatened both archaeological sites and a large expanse of upland mire on Mynydd y Drum. Excavations of two cairns and a length of post-medieval trackway were conducted there by the Clwyd-Powys Archaeological Trust in the summer of 1987. These were accompanied by palaeoecological work to ascertain both the post-glacial environmental history of Mynydd y Drum and the contemporary environmental setting of the two cairns. Evidence suggests that the most dramatic impact upon local woodland was in the early Bronze Age. The evidence for former extensive deciduous woodlands on Mynydd y Drum now offers British Coal a wider range of land restoration goals, for consideration when the opencast mining ceases. -from Author

Using fire scars and growth release in subfossil Scots pine to reconstruct prehistoric fires

Fire scars indicating low- to moderate-intensity fires on peat deposits have been sampled from subfossil Scots pine (Pinus sylvestris L.) at sites in England, Wales and south-west Ireland. Analysis of ring-width responses to one fire event in 2800 BC illustrates its rejuvenating effect on Pinus sylvestris woodland, supporting a growing body of modern and palaeoecological data that illustrates the regenerative role played by fire in persistence of Pinus sylvestris woodland. Both the scale and timing of these fires suggest that infrequent low- to moderate-intensity fires are sufficient to stimulate Pinus sylvestris growth. This effect is shown by average increases in ring-width following the fire of between 0.62 and 1.16 mm in non-scarred trees and between 0.92 and 2.74 mm in fire-scarred individuals. Growth release in non-scarred trees may prove to be a more reliable method of detecting fire than using the relatively rare fire scars alone. Radii at time of scarring varied between 1.85 and 11.2 cm, much smaller than is predicted to survive from modern studies. © 2000 Elsevier Science B.V

Modified versions of a traditional peatcutting tool to improve field sampling of peat monoliths

Describes a stainless steel peat collector based on a traditional design which, together with a monolith tin, can be used to extract metre-long samples from peat bogs and other soft sediments. -K.Clayto

Recording and Reconstruction of Wood Macrofossils in Three-Dimensions

Building on an upsurge of interest in European wetland archaeology, which has led to methodological advances in field techniques, a new palaeoecological technique is outlined to enable reconstruction of wood macrofossils in their originalin situpositions within a peat deposit. Such three-dimensional reconstruction provides data on the temporal sequence and succession of mire woodland phases; these can be related to the fossil pollen record and to evidence of past human impact. Chronology building using tree ring-width series, is facilitated, and may assist in dating site records. The technique has wider application at sites where subfossiliferous peat is underlain by sand substrates, aiding palaeoenvironmental reconstruction and interpretation of the cultural landscape. © 1995 Academic Press Limited

Sweet chestnut (Castanea sativa Mill.) in Britain: its dendrochronological potential

In Britain, where sweet chestnut is classified as an archaeophyte of Roman introduction, there are many ancient sweet chestnut trees and woodlands significant for conservation, yet no dendrochronological assessment has been made of them. This paper describes an attempt to assess the dendrochronological potential of sweet chestnut wood. Eight sweet chestnut trees (veteran trees in parkland and mature trees and coppice-grown stems in woodland) from five sites in western England were sampled by coring living wood and by cutting sections in fallen dead wood, to enable microscopic analysis of growth ring parameters. Four trees from three sites were cross-matched to form a 295-year chronology from AD 1716 to AD 2011. The annual resolution of the chronology was confirmed by regional cross-dating with oak reference chronologies. The ages for these chestnut trees range from circa AD 1668 to AD 1940. It is concluded that oak reference chronologies can be used to date sweet chestnut wood, with benefits for archaeological, historic building and palaeoenvironmental assessments. The extraction of sawn sections from dead veteran trees and their dendrochronological analysis indicates a more reliable and benign approach to dating ancient trees in historic landscapes compared with coring

Dendrochronological assessment of British veteran sweet chestnut (Castanea sativa) trees: Successful cross-matching, and cross-dating with British and French oak (Quercus) chronologies

Across Britain and continental Europe there are many ancient Castanea sativa trees of great significance for natural and cultural heritage, yet scant assessment has been made of them for dendrochronological information. This paper describes the dendrochronological analysis of 28 Castanea sativa trees (veteran historic trees, forest trees and coppice stems) sampled from 15 sites in southern Britain: 56 growth-ring sequences were collected for analysis, by boring living trees and by cutting transverse sections from dead fallen trees and previously cut stumps. Twenty-three single-tree sequences from 14 sites were cross-matched (t ≥3.5) and then cross-dated with 17 oak Quercus reference chronologies from England and northern France: a Castanea sativa master chronology spanning AD 1660–2014 has been created. The results demonstrate the viability of dendrochronological analysis of Castanea sativa wood; and confirm that Castanea sativa can be cross-dated with oak Quercus reference chronologies, inter-regionally and inter-nationally. The findings provide the potential means for dating Castanea sativa timbers sampled from palaeoenvironmental and historical contexts. The extraction of sawn sections from long-dead (up to 60 years in this study) trees and stumps is proven to be a reliable method for dating veteran trees in cultural landscapes and ancient woodlands; and for revealing the growth history of historic/iconic trees. The germination dates calculated for the Castanea sativa trees in this study span the period AD 1640–1943. The inaccuracy of estimating veteran Castanea sativa tree ages from girth measurements is highlighted

Introducing a new breed of wine yeast: interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast and Saccharomyces mikatae

Interspecific hybrids are commonplace in agriculture and horticulture; bread wheat and grapefruit are but two examples. The benefits derived from interspecific hybridisation include the potential of generating advantageous transgressive phenotypes. This paper describes the generation of a new breed of wine yeast by interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species hitherto not associated with industrial fermentation environs. While commercially available wine yeast strains provide consistent and reliable fermentations, wines produced using single inocula are thought to lack the sensory complexity and rounded palate structure obtained from spontaneous fermentations. In contrast, interspecific yeast hybrids have the potential to deliver increased complexity to wine sensory properties and alternative wine styles through the formation of novel, and wider ranging, yeast volatile fermentation metabolite profiles, whilst maintaining the robustness of the wine yeast parent. Screening of newly generated hybrids from a cross between a S. cerevisiae wine yeast and S. mikatae (closely-related but ecologically distant members of the Saccharomyces sensu stricto clade), has identified progeny with robust fermentation properties and winemaking potential. Chemical analysis showed that, relative to the S. cerevisiae wine yeast parent, hybrids produced wines with different concentrations of volatile metabolites that are known to contribute to wine flavour and aroma, including flavour compounds associated with non-Saccharomyces species. The new S. cerevisiae x S. mikatae hybrids have the potential to produce complex wines akin to products of spontaneous fermentation while giving winemakers the safeguard of an inoculated ferment.Jennifer R. Bellon, Frank Schmid, Dimitra L. Capone, Barbara L. Dunn, Paul J. Chamber

Contemporary carbon fluxes do not reflect the long-term carbon balance for an Atlantic blanket bog

Peatlands are one of the largest terrestrial stores of carbon. Carbon exchange in peatlands is often assessed solely by measurement of contemporary fluxes; however, these fluxes frequently indicate a much stronger sink strength than that measured by the rate of C accumulation in the peat profile over longer timescales. Here we compare profile-based measurements of C accumulation with the published net ecosystem C balance for the largest peatland area in Britain, the Flow Country of northern Scotland. We estimate the long-term rate of C accumulation to be 15.4 g C m−2 yr−1 for a site where a recent eddy covariance study has suggested contemporary C uptake more than six times greater (99.37 g C m−2 yr−1). Our estimate is supported by two further long-term C accumulation records from nearby sites which give comparable results. We demonstrate that a strong contemporary C sink strength may not equate to a strong long-term sink and explore reasons for this disparity. We recommend that contemporary C sequestration should be viewed in the context of the long-term ecological drivers, such as fires, ecohydrological feedbacks and the changing quality of litter inputs