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Matter Accumulation (matter + accumulation)

Distribution by Scientific Domains
Life Sciences57%
Earth and Environmental Science35%

Kinds of Matter Accumulation

  • dry matter accumulation
    		•
  • organic matter accumulation
    		•

    Selected Abstracts

    Effects of Nitrogen on Dry Matter Accumulation and Productivity of Three Cropping Systems and Residual Effects on Wheat in Deep Vertisols of Central India

    JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2002
    P. Ramesh
    A field experiment was conducted on deep vertisols of Bhopal, India to study the effects of three levels of nitrogen (N), namely 0, 75 and 100 % of the recommended dose of nitrogen (RDN), on the dry matter accumulation (DMA) and productivity of three cropping systems (sole soybean, sole sorghum and soybean + sorghum intercropping) during the rainy season and their residual effect on the subsequent wheat crop during the post-rainy season. During the rainy season, sole sorghum was found to have significantly higher DMA and productivity in terms of soybean equivalent yield (SEY) than sole soybean or soybean + sorghum intercropping. Increasing the N dose from 0 to 100 % RDN significantly improved the DMA and SEY. At a low fertility level (N0), soybean + sorghum intercropping was found to be more productive, while at a high fertility level (100 % RDN), sole sorghum was more productive than the other two cropping systems. However, during the post-rainy season, sole soybean as the preceding crop gave the highest DMA and seed yield of wheat, which were similar to those found with soybean + sorghum intercropping. Sorghum followed by wheat gave the lowest DMA and seed yield of wheat. Application of 100 % RDN irrespective of cropping system during the preceding crop improved the DMA of wheat but not its seed yield. However, N applied to the wheat crop significantly increased its DMA and seed yield. Einfluss von Stickstoff auf Trockenmasseakkumulation und Produktivität von drei Anbausystemen und deren Rückstandswirkung auf Weizen in einem tiefen Vertisol Zentralindiens Ein Feldexperiment wurde durchgeführt auf einem tiefen Vertisol bei Bhopal, Indien, um den Einfluss von drei Stickstoffkonzentrationen 0, 75 und 100 % der empfohlenen Stickstoffmenge (RDN) auf die Trockenmasseakkumulation (DMA) und Produktivität von drei Anbausystemen (Reinanbau Sojabohne, Reinanbau Sorghum und Sojabohne + Sorghum Mischanbau) während der Regensaison und deren Nachwirkungen auf den folgenden Anbau von Weizen während der Nachregensaison zu untersuchen. Während der Regensaison war der Reinanbau von Sorghum signifikant höher in DMA und in der Produktivität in Form von Ertragsäquivalenten für Sojabohnen (SEY) im Vergleich zu einem Reinanbau von Sojabohne oder einem Mischanbau von Sojabohne + Sorghum. Eine Erhöhung der N-Anwendung von 0 bis 100 % RDN erhöhte Signifikanz DMA und SEY. Unter der niedrigen Düngung (N0) erwies sich Sojabohne + Sorghum Mischanbau als produktiver im Vergleich zu einer hohen Düngungeranwendung (100 % RDN), Reinanbau war produktiver als die anderen beiden Anbausysteme. Allerdings während der Nachregensaison erwies sich der Reinanbau von Sojabohnen vor Weizen als die höchste DMA und Ertragsmenge, was mit dem Sojabohnen + Sorghum Mischanbau vergleichbar war. Sorghum gefolgt von Weizen ergab den geringsten DMA und niedrigsten Weizenertrag. Die Anwendung von 100 % RDN erhöhte unabhängig von dem Anbausystem der vorhergehenden Kulturpflanzen DMA von Weizen aber nicht den Kornertrag. Allerdings erhöhte N im Weizenanbau signifikant sowohl DMA als auch Kornertrag. [source]

    Mineral surfaces and soil organic matter

    EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2003
    K. Kaiser
    Summary The organic carbon content of soil is positively related to the specific surface area (SSA), but large amounts of organic matter in soil result in reduced SSA as determined by applying the Brunauer,Emmett,Teller (BET) equation to the adsorption of N2. To elucidate some of the controlling mechanisms of this relation, we determined the SSA and the enthalpy of N2 adsorption of separates with a density > 1.6 g cm,3 from 196 mineral horizons of forest soils before and after removal of organic matter with NaOCl. Likewise, we investigated these characteristics before and after sorption of increasing amounts of organic matter to four mineral soil samples, oxides (amorphous Al(OH)3, gibbsite, ferrihydrite, goethite, haematite), and phyllosilicates (kaolinite, illite). Sorption of organic matter reduced the SSA, depending on the amount sorbed and the type of mineral. The reduction in SSA decreased at larger organic matter loadings. The SSA of the mineral soils was positively related to the content of Fe oxyhydroxides and negatively related to the content of organic C. The strong reduction in SSA at small loadings was due primarily to the decrease in the micropores to which N2 was accessible. This suggests preferential sorption of organic matter at reactive sites in or at the mouths of micropores during the initial sorption and attachment to less reactive sites at increasing loadings. The exponential decrease of the heat of gas adsorption with the surface loading points also to a filling or clogging of micropores at early stages of organic matter accumulation. Desorption induced a small recovery of the total SSA but not of the micropore surface area. Destruction of organic matter increased the SSA of all soil samples. The SSA of the uncovered mineral matrix related strongly to the amounts of Fe oxyhydroxides and the clay. Normalized to C removed, the increase in SSA was small in topsoils and illuvial horizons of Podzols rich in C and large for the subsoils containing little C. This suggests that micropores preferentially associate with organic matter, especially at small loadings. The coverage of the surface of the soil mineral matrix as calculated from the SSA before and after destruction of organic matter was correlated only with depth, and the relation appeared to be linear. We conclude that mineralogy is the primary control of the relation between surface area and sorption of organic matter within same soil compartments (i.e. horizons). But at the scale of complete profiles, the surface accumulation and stabilization of organic matter is additionally determined by its input. [source]

    Dissolved organic matter in small streams along a gradient from discontinuous to continuous permafrost

    GLOBAL CHANGE BIOLOGY, Issue 9 2004
    Masayuki Kawahigashi
    Abstract The Yenisei river passes every type of permafrost regime, from south to north, being characterized by increasing continuity of the permafrost and by decreasing thickness of the active layer. We used that situation to test the hypothesis that amounts and properties of dissolved organic matter (DOM) in small streams draining forested catchments respond to different permafrost regimes. Water samples were taken from eight tributaries along the Yenisei between 67°30,N and 65°49,N latitude. The samples were analysed for dissolved organic carbon (DOC) and nitrogen (DON) and DOM was characterized by its chemical composition (XAD-8 fractionation, sugars, lignin phenols, amino acids, protein, UV and fluorescence spectroscopy), and its biodegradability. Most properties of the tributary waters varied depending on latitude. The higher the latitude, the higher were DOC, DON and the proportion of the hydrophobic fraction of DOC. The contribution of hexoses and pentoses to DOC were higher in southern tributaries; on the other hand, phenolic compounds were more abundant in northern tributaries. Mineralizable DOC ranged between 4% and 28% of total DOC. DOM in northern tributaries was significantly (P<0.05) less biodegradable than that in southern tributaries reflecting the differences in the chemical properties of DOM. Our results suggest that the differences in DOM properties are mainly attributed to differences of permafrost regime, affecting depth of active layer, soil organic matter accumulation and vegetation. Soil organic matter and vegetation determine the amount and composition of DOM produced in the catchments while the depth of the active layer likely controls the quantity and quality of DOM exported to streams. Sorptive interactions of DOM with the soil mineral phase typically increase with depth. The results imply that a northern shift of discontinuous permafrost likely will change in the long term the input of DOM into the Yenisei and thus probably into the Kara Sea. [source]

    Factors Affecting Macroinvertebrate Richness and Diversity in Portuguese Streams: a Two-Scale Analysis

    INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 2 2004
    Manuel A. S. Graça
    Abstract We analysed the spatial patterns in macroinvertebrate taxon richness and abundance at two scales: sampling unit and basin. We sampled 12 stream sites in three zones of Portugal, differing in climate geomorphology and water chemistry. At a sampling unit scale, substratum organic matter content, depth and the dominant size of substratum particles were correlated with numbers of taxa and individuals. We propose that the number of taxa at a small scale depends on the number of individuals, which in turn is the result of organic matter accumulation, hydrologic and substratum characteristics. The environmental parameters better explaining the large-scale biological data were temperature, minimum size of substratum particles and pH. Regardless of the relative importance of variable types and mechanisms regulating stream invertebrates along the climatic gradient, rivers from the North and Centre appeared to be richer in taxa than the typically Mediterranean streams in the South. [source]

    Effects of Nitrogen on Dry Matter Accumulation and Productivity of Three Cropping Systems and Residual Effects on Wheat in Deep Vertisols of Central India

    JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2002
    P. Ramesh
    A field experiment was conducted on deep vertisols of Bhopal, India to study the effects of three levels of nitrogen (N), namely 0, 75 and 100 % of the recommended dose of nitrogen (RDN), on the dry matter accumulation (DMA) and productivity of three cropping systems (sole soybean, sole sorghum and soybean + sorghum intercropping) during the rainy season and their residual effect on the subsequent wheat crop during the post-rainy season. During the rainy season, sole sorghum was found to have significantly higher DMA and productivity in terms of soybean equivalent yield (SEY) than sole soybean or soybean + sorghum intercropping. Increasing the N dose from 0 to 100 % RDN significantly improved the DMA and SEY. At a low fertility level (N0), soybean + sorghum intercropping was found to be more productive, while at a high fertility level (100 % RDN), sole sorghum was more productive than the other two cropping systems. However, during the post-rainy season, sole soybean as the preceding crop gave the highest DMA and seed yield of wheat, which were similar to those found with soybean + sorghum intercropping. Sorghum followed by wheat gave the lowest DMA and seed yield of wheat. Application of 100 % RDN irrespective of cropping system during the preceding crop improved the DMA of wheat but not its seed yield. However, N applied to the wheat crop significantly increased its DMA and seed yield. Einfluss von Stickstoff auf Trockenmasseakkumulation und Produktivität von drei Anbausystemen und deren Rückstandswirkung auf Weizen in einem tiefen Vertisol Zentralindiens Ein Feldexperiment wurde durchgeführt auf einem tiefen Vertisol bei Bhopal, Indien, um den Einfluss von drei Stickstoffkonzentrationen 0, 75 und 100 % der empfohlenen Stickstoffmenge (RDN) auf die Trockenmasseakkumulation (DMA) und Produktivität von drei Anbausystemen (Reinanbau Sojabohne, Reinanbau Sorghum und Sojabohne + Sorghum Mischanbau) während der Regensaison und deren Nachwirkungen auf den folgenden Anbau von Weizen während der Nachregensaison zu untersuchen. Während der Regensaison war der Reinanbau von Sorghum signifikant höher in DMA und in der Produktivität in Form von Ertragsäquivalenten für Sojabohnen (SEY) im Vergleich zu einem Reinanbau von Sojabohne oder einem Mischanbau von Sojabohne + Sorghum. Eine Erhöhung der N-Anwendung von 0 bis 100 % RDN erhöhte Signifikanz DMA und SEY. Unter der niedrigen Düngung (N0) erwies sich Sojabohne + Sorghum Mischanbau als produktiver im Vergleich zu einer hohen Düngungeranwendung (100 % RDN), Reinanbau war produktiver als die anderen beiden Anbausysteme. Allerdings während der Nachregensaison erwies sich der Reinanbau von Sojabohnen vor Weizen als die höchste DMA und Ertragsmenge, was mit dem Sojabohnen + Sorghum Mischanbau vergleichbar war. Sorghum gefolgt von Weizen ergab den geringsten DMA und niedrigsten Weizenertrag. Die Anwendung von 100 % RDN erhöhte unabhängig von dem Anbausystem der vorhergehenden Kulturpflanzen DMA von Weizen aber nicht den Kornertrag. Allerdings erhöhte N im Weizenanbau signifikant sowohl DMA als auch Kornertrag. [source]

    The use of chronosequences in studies of ecological succession and soil development

    JOURNAL OF ECOLOGY, Issue 4 2010
    Lawrence R. Walker
    Summary 1.,Chronosequences and associated space-for-time substitutions are an important and often necessary tool for studying temporal dynamics of plant communities and soil development across multiple time-scales. However, they are often used inappropriately, leading to false conclusions about ecological patterns and processes, which has prompted recent strong criticism of the approach. Here, we evaluate when chronosequences may or may not be appropriate for studying community and ecosystem development. 2.,Chronosequences are appropriate to study plant succession at decadal to millennial time-scales when there is evidence that sites of different ages are following the same trajectory. They can also be reliably used to study aspects of soil development that occur between temporally linked sites over time-scales of centuries to millennia, sometimes independently of their application to shorter-term plant and soil biological communities. 3.,Some characteristics of changing plant and soil biological communities (e.g. species richness, plant cover, vegetation structure, soil organic matter accumulation) are more likely to be related in a predictable and temporally linear manner than are other characteristics (e.g. species composition and abundance) and are therefore more reliably studied using a chronosequence approach. 4.,Chronosequences are most appropriate for studying communities that are following convergent successional trajectories and have low biodiversity, rapid species turnover and low frequency and severity of disturbance. Chronosequences are least suitable for studying successional trajectories that are divergent, species-rich, highly disturbed or arrested in time because then there are often major difficulties in determining temporal linkages between stages. 5.,Synthesis. We conclude that, when successional trajectories exceed the life span of investigators and the experimental and observational studies that they perform, temporal change can be successfully explored through the judicious use of chronosequences. [source]

    A record of Late Pleistocene and Holocene carbon accumulation and climate change from an equatorial peat bog (Kalimantan, Indonesia): implications for past, present and future carbon dynamics

    JOURNAL OF QUATERNARY SCIENCE, Issue 7 2004
    S. E. Page
    Abstract A 9.5,m core from an inland peatland in Kalimantan, Indonesia, reveals organic matter accumulation started around 26,000,cal.,yr,BP, providing the oldest reported initiation date for lowland ombrotrophic peat formation in SE Asia. The core shows clear evidence for differential rates of peat formation and carbon storage. A short period of initial accumulation is followed by a slow rate during the LGM, with fastest accumulation during the Holocene. Between ,13,000 and 8000,cal.,yr,BP, >,450,cm of peat were deposited, with highest rates of peat (>,2,mm,yr,1) and carbon (>,90,g,C,m,2,yr,1) accumulation between 9530 and 8590,cal.,yr,BP. These data suggest that Kalimantan peatlands acted as a large sink of atmospheric CO2 at this time. Slower rates of peat (0.15,0.38,mm,yr,1) and carbon (7.4,24.0,g,C,m,2,yr,1) accumulation between ,8000 and 500,cal.,yr,BP coincide with rapid peat formation in coastal locations elsewhere in SE Asia. The average LORCA (long-term apparent carbon accumulation rate) for the 9.5,m core is 56,g,C,m,2,yr,1. These data suggest that studies of global carbon sources, sinks and their dynamics need to include information on the past and present sizeable peat deposits of the tropics. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    Sex-specific responses of Populus cathayana to drought and elevated temperatures

    PLANT CELL & ENVIRONMENT, Issue 6 2008
    XIAO XU
    ABSTRACT Dioecious plant species represent an important component of terrestrial ecosystems. Yet, little is known about sex-specific responses to drought and elevated temperatures. Populus cathayana Rehd, which is a dioecious, deciduous tree species, widely distributed in the northern, central and southwestern regions of China, was employed as a model species in our study. In closed-top chamber experiments, sex-specific morphological, physiological and biochemical responses of P. cathayana to drought and different elevated temperatures were investigated. Compared with the controls, drought significantly decreased the growth and the net photosynthesis rate (A), and increased the intrinsic water use efficiency (WUEi), carbon isotope composition (,13C), and the malondialdehyde (MDA) and abscisic acid (ABA) contents in droughted plants. In contrast, elevated temperatures significantly promoted the growth and the A, but decreased the WUEi, ,13C, MDA and ABA contents in well-watered individuals. When compared with males, elevated temperatures induced well-watered females to express a greater increase in the height growth (HG), basal diameter (BD), leaf area (LA), total number of leaves (TNL), dry matter accumulation (DMA) and specific leaf area (SLA), and a lower decrease in the A value, transpiration (E), stomatal conductance (gs), MDA and ABA contents, while elevated temperatures induced drought-stressed females to exhibit lower values of HG, BD, LA, TNL, DMA, A, E, gs and the intercellular CO2 concentration (Ci), and higher levels of SLA, WUEi, ,13C, MDA and ABA contents. Our results indicated that the female individuals of P. cathayana are more responsive and suffer from greater negative effects than do males when grown under environments with increased drought stress and elevated temperature. [source]

    Influence of minisett sizes on dry matter accumulation and fresh tuber yield of white Guinea yam (Dioscorea rotundata)

    ANNALS OF APPLIED BIOLOGY, Issue 2 2009
    K.E. Law-Ogbomo
    Abstract Studies were conducted in 2005 and 2006 at Irrua, Nigeria, to determine the performance of various sizes of minisetts of Dioscorea rotundata cv. ,Obiaoturugo' evaluated for size and yield of yield matter and seed yams. These trials involved a macrosett (250 g) and six minisett sizes (25, 30, 35, 40, 45 and 50 g) in a randomised block design with four replicates. The results indicated that larger minisetts had higher degree of field establishment, foliation, leaf area index, total dry weight, percentage of leaf dry matter and net assimilation rate. These growth parameters influenced higher crop growth rate, which was responsible for higher fresh tuber yield. The macrosett's fresh tuber yield was the greatest (20.48 t ha,1) but had the least multiplication ratio (8.19). The greatest multiplication ratio was obtained from 30-g setts. [source]

    Crop traits and the tolerance of wheat and barley to foliar disease

    ANNALS OF APPLIED BIOLOGY, Issue 2 2009
    I.J. Bingham
    Abstract The relationship between yield loss and disease severity can differ widely between crops. This has given rise to the concept of disease tolerance, with some crops exhibiting a smaller yield loss under a given severity of disease than others. Genetic improvement to minimise yield loss under disease is an attractive goal, as it exerts little or no selection pressure on pathogen populations, and could form a useful component of durable disease management programmes. However, progress towards this end requires a thorough understanding of the phenotypic traits that influence the response of yield to disease, their genetic control and the possible trade-offs involved with other desirable agronomic characteristics. This paper examines the candidate crop traits that may confer tolerance of foliar disease in wheat and barley and reviews evidence of genetic variation in their expression. In wheat grown under the relatively low light conditions of North-West Europe, post-anthesis source (assimilate supply) and grain sink capacity (capacity for dry matter accumulation) appear to be closely balanced. Traits associated with maintaining post-anthesis radiation interception and radiation use efficiency in spite of disease may confer tolerance. The most promising traits include a larger flag leaf and compensatory increases in photosynthetic rate in non-infected parts of leaves. In barley, yield is often more strongly sink limited, and early-season disease management is required to protect the formation of potential grain sites. A wider range of potential traits may influence tolerance including compensatory adjustments in leaf growth and morphology, and differences in the sensitivity of tiller and spikelet mortality to photoassimilate supply. Different methods for quantifying tolerance are suggested depending on the trait of interest. [source]

    Protein and oil concentration of soybean seed cultured in vitro using nutrient solutions of differing glutamine concentration

    ANNALS OF APPLIED BIOLOGY, Issue 2 2004
    ANTONIO E PIPOLO
    Summary Oil and protein are the most valuable components of soybean seed. Evidence indicates that growth and composition of soybean seed are controlled by supplies of carbon and nitrogen provided by the maternal plant to the seed, but it is difficult experimentally to control and quantify the precise amount of carbon and nitrogen provided to the seed by the whole plant. To examine whether oil and protein concentrations are affected by the supply of nitrogen to the seed, immature soybean seeds (Glycine max cv. Williams 82) were grown in vitro in nutrient solutions containing 20, 40, 60 or 80 mM of glutamine. The seeds were incubated in Erlenmeyer flasks for 8 days at 25°C. The rate of dry matter accumulation changed from 7.2 to 8.3 mg seed,1 day,1 as the glutamine concentration increased from 20 to 80 mM but the differences were not significant (P 0.05). Seed protein concentration increased as glutamine concentration increased from 294 mg g,1 at 20 mM glutamine to as high as 445 mg g,1 at 80 mM glutamine. Typical in vivo protein concentration of mature soybean seeds is about 400 mg g,1. Oil and protein concentrations were negatively correlated (r2= 0.44), which indicates that oil and protein synthesis are interrelated. Protein synthesis was favoured over oil synthesis when nitrogen became more abundant. The seeds used in this study clearly demonstrated a capacity to respond to nitrogen availability with changes in seed protein concentration. [source]

    Effects of pioneer shrubs on the recruitment of the fleshy-fruited tree Olea europaea ssp. cuspidata in Afromontane savanna

    APPLIED VEGETATION SCIENCE, Issue 1 2006
    Raf Aerts
    Abstract Question: Is seedling recruitment of a fleshy-fruited tree in degraded Afromontane savanna dependent on shelter from pioneer shrubs, and is shelter availability related to shrub traits? Location: Degraded montane savanna in northern Ethiopia (13°36,N, 39°21,E). Method: Nurse plants of Olea europaea ssp. cuspidata seedlings were recorded using T-square plotless sampling and clustered according to shrub traits, using Ward's method after Principal Components Analysis. Facilitation was further examined through experimental planting and Kaplan-Meier survival analysis. Results: Both in grazed and protected areas, Olea recruits were found exclusively under shrubs, primarily under Euclea racemosa although Acacia etbaica was more abundant. Olea recruitment is distributed randomly at landscape scale, but depends on shelter at patch scale. Shelter ability is related to shrub shape and species identity. Dense multi-stemmed shrubs with a wide base and crown on a mulch-rich mound are key recruitment foci. Euclea shrubs have these favoured traits and probably act as preferential perching sites for avian seed dispersers. Soil and organic matter accumulation under Euclea shrubs may also create favourable conditions for Olea germination and survival. Experimentally planted seedlings had a better chance for survival under Euclea. Conclusions:Olea regeneration is probably subject to both passive (disperser-mediated) and active facilitation. Small changes of shrub traits can alter the suitability of a patch for Olea recruitment. Protection of shrubs can increase facilitation for seedlings, while pruning may reduce competition for saplings and thus enhance forest succession. Planting of raised Olea seedlings under Euclea shrubs in years with a good rainy season may further assist forest restoration. [source]

    Soil Phosphorus Fractionation during Forest Development on Landslide Scars in the Luquillo Mountains, Puerto Rico,

    BIOTROPICA, Issue 1 2002
    Jacqueline Frizano
    ABSTRACT Mineral soils from a chronosequence of landslide scars ranging in age from 1 to more than 55 years in a subtropical montane rain forest of eastern Puerto Rico were used to determine the rate at which labile P capital recovers during primary succession. Nine organic and inorganic soil P fractions were measured using the Hedley sequential extraction procedure. Deep soil cores (9 m) from a nearby site were also analyzed to determine the distribution of P fractions below the solum. Litterfall P was measured for two years in the landslide scars to estimate allochthonous litter P inputs, and published precipitation data were used to estimate annual atmospheric inputs of P to the recovering forests. In the upper solum (0,10 cm), organic matter increased with landslide age, as did resin-Pi, labile P (defined here as resin-Pi + HCO3 -Pi + HCO3 -Po) and total organic P. Occluded P decreased with increasing landslide age. No significant changes in P concentrations or pools were observed in 10 to 35 or in 35 to 60 cm depth intervals across the chronosequence. Labile soil P increased to approximately two-thirds of the pre-disturbance levels in the oldest landslide scar (>55 yr). Thus, plants, their associated microflora/fauna, and P inputs from off-site substantially altered the distribution of soil P fractions during forest recovery. Across the chronosequence, the increase in labile P accumulated in soil and biomass appeared to be greater than the estimated allochthonous inputs from litter and precipitation, indicating that as the forest developed, some occluded P may have been released for use by soil biota. Resin-Pi and labile P were correlated with soil organic matter content, suggesting, as in other highly weathered soils, organic matter accumulation and turnover are important in maintaining labile P pools. Primary mineral P (apatite) was scarce, even in deep soil cores. [source]

    A 3000-year palaeoenvironmental record from annually laminated sediment of Lake Korttajarvi, central Finland

    BOREAS, Issue 4 2003
    MIA TILJANDER
    High-resolution physical analyses (varve thickness and relative X-ray density) were conducted on a 3000-year varved sediment sequence in Lake Korttajarvi, central Finland. Climate and the local environment strongly influence the properties of the lake sediments, and, through a combination of physical proxies, severe and favourable climate periods and anthropogenic effects on sedimentation with an annual to decadal resolution could be detected. We observed previously identified historical climate periods in the Lake Korttajarvi varve record. The Medieval Climate Anomaly (often termed the Medieval Warm Period) of AD 980,1250, which is characterized by highly organic sediment and a minor minerogenic flux during mild winters, started and terminated abruptly, but also included a short (30-year) colder period lasting between AD 1115 and AD 1145. The Little Ice Age, however, was not clear in our record, although there were two minor cooling periods in AD 1580,1630 and AD 1650,1710. Natural variability in the sediment record was disrupted by increased human impact in the catchment area at AD 1720. There is a distinct positive anomaly in mineral matter accumulation between 907 and 875 BC, which indicates more severe climate conditions. This period exists contemporary with a cold event, recorded worldwide, c. 2800 years ago. [source]