•Bourtangermoor, former extensive raised bog in the north of the Netherlands.•Bourtangermoor bog iron ores, unique in size and mineralogy.•Historic literature and maps are compared to present-day ...seepage data.•Present-day seepage good proxy to reconstruct historic bog iron ores in raised bogs.•Local geology and hydrology dictated location of seepage from deep aquifers.•Bog iron ores both beneficial and harmful for wetland restoration.•Use of bog iron ores as source of iron could give information on the use and perception of raised bogs by past societies.•Lagg dictated the location of bog iron ores.
Bog iron ores are well-known lumps of Fe-(oxy)hydroxides (goethite, limonite) found along streams and in seasonally flooded, low-lying areas. Historic literature of the Bourtangermoor, a former raised bog in the north of the Netherlands and adjacent Germany, however, revealed a second, rare type of bog iron ores, exclusively composed of siderite (Fe-carbonate) with accessory vivianite (Fe-phosphate), minerals only stable under anaerobic conditions. In this research we compared historic literature and maps mainly from the first half of the 20th century, when parts of the bog were still intact, with present-day seepage data to allow analysis whether recent seepage could be used to reconstruct the location of historic bog iron ores in the Bourtangermoor. Our results showed two distinctly different present-day seepage patterns: one related to shallow aquifers, one to deeper aquifers. Present-day seepage from deeper aquifers was related to historic siderite bog iron ore deposits (deposits exclusively limited to the lower, early formed, still groundwater-fed part of the raised bog). Present-day seepage – deep or shallow – did not show a clear relation to historic classic-type bog iron ores (lumps of goethite and limonite). We conclude that present-day seepage patterns from deep aquifers can be used to reconstruct historic siderite bog iron ores in the Bourtangermoor. Present-day seepage patterns – deep or shallow – are however not representative for historic bog iron ores deposited along streams. Our results could be useful for wetland restoration projects as iron can contribute to nutrient-poor conditions by capturing phosphate in bog iron ores and for archaeological research regarding the potential use of bog iron ores by past societies.
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•Raised bog water table fluctuations vary at nearby points and cannot be extrapolated.•Hydrological similarities emerge according to the types of raised bog habitats.•A correlation ...was found between hydrological and botanical indicators and NDVI/NDWI.•NDVI/NDWI can be used as indicators of hydroclimatic trends.
Peatland vegetation requires water-logged conditions for peat-forming plant communities to survive. Changes in water regimes have been found to alter the soil environment and cause shifts in species composition. Occasionally, the spatial and chronological constraints in water table monitoring impede the correct evaluation of the status of these sensitive ecohydrological systems. Therefore, it is important to combine in situ and remote sensing methods to assess ecohydrological diversity over large areas of threatened peatland ecosystems. The present study assessed the relationship between hydrological indicators (the in situ water table fluctuations of 57 measurement wells and five study plots in the 2019 and 2020 growing seasons); botanical indicators (in situ species composition in three raised bog habitat types, namely, bog woodland, a semi-open raised bog, and an open raised bog); and spectral indices (NDVI – Normalised Difference Vegetation Index and NDWI – Normalised Difference Water Index, 2015–2020, Sentinel 2) for the evaluation of heterogeneous raised bog spatial patterns and temporal change. There were statistically significant relationships between vegetation and water table depth in different raised bog habitat types. Deeper water tables prevailed in woodland habitats (trees, green mosses, Rhododendron tomentosum) and vice versa in areas where open raised bog plants (Sphagnum) occupied the surface. Moderate relationships (r > |0.4|, p <.05) were detected between some of the botanical and hydrological indicators and spectral indices. The application of high-resolution remote sensing data may be useful for raised bog measurements, and changes in vegetation cover and related spectral indices may become hydroclimatic indicators.
Afforestation is a significant cause of global peatland degradation. In some regions, afforested bogs are now undergoing clear-felling and restoration, often known as forest-to-bog restoration. We ...studied differences in water-table depth (WTD) and porewater chemistry between intact, afforested, and restored bogs at a raised bog and blanket bog location. Solute concentrations and principal component analysis suggested that water-table drawdown and higher electrical conductivity (EC) and ammonium (NH4-N) concentrations were associated with afforestation. In contrast, higher dissolved organic carbon (DOC) and phosphate (PO4-P) concentrations were associated with deforestation. Drying-rewetting cycles influenced seasonal variability in solute concentrations, particularly in shallower porewater at the raised bog location. WTD was significantly deeper in the oldest raised bog restoration site (~9 years post-restoration) than the intact bog (mean difference = 6.2 cm). However, WTD in the oldest blanket bog restoration site (~17 years post-restoration), where furrows had been blocked, was comparable to the intact bog (mean difference = 1.2 cm). When averaged for all porewater depths, NH4-N concentrations were significantly higher in the afforested than the intact sites (mean difference = 0.77 mg L−1) whereas significant differences between the oldest restoration sites and the intact sites included higher PO4-P (mean difference = 70 μg L−1) in the raised bog and higher DOC (mean difference = 5.6 mg L−1), EC (mean difference = 19 μS cm−1) and lower SUVA254 (mean difference = 0.13 L mg−1 m−1) in the blanket bog. Results indicate felled waste (brash) may be a significant source of soluble C and PO4-P. Mean porewater PO4-P concentrations were between two and five times higher in furrows and drains in which brash had accumulated compared to other locations in the same sites where brash had not accumulated. Creating and maintaining brash-free buffer zones may therefore minimise freshwater impacts.
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•Elevated electrical conductivity and NH4-N were associated with the forestry.•Elevated PO4-P and DOC were associated with restoration and clear-felling.•WTD was not significantly different from the intact bog in the restored blanket bog.•PO4-P was significantly higher where brash accumulated in drains and furrows.•The legacy effects of afforestation were influenced by sea-salt deposition.
The results of dendrochronological and palynological analyses of subfossil pine trees occurring in the peat deposits of the Puścizna Wielka raised bog (Polish Carpathians, Southern Poland) – the only ...site with numerous subfossil pine trees in the mountainous regions of Central Europe presently known – indicate that the majority of the tree populations grew in the peat bog during the periods ca 5415–3940 cal BP and 3050–2560 cal BP. Several forestless episodes, dated to 5245–5155 cal BP, 4525–4395 cal BP and 3940–3050 cal BP, were preceded by tree dying-off phases caused by an extreme periodical increase in humidity and general climate cooling trends. These events are documented based on analyses of pollen and non-pollen palynomorph assemblages, dendrochronological analyses of the trees, as well as numerous radiocarbon datings of the sediment horizons occurring within the peat bog profile. The phases of germinations, and, in turn, of tree and shrub invasions of the peat bog areas have been closely connected to drying and occasional warming of the regional climate. The last of the forestless periods began about 2600 years ago and continued up to the very recent times. Currently, as a result of desiccation of the peat bog and the lowering of the groundwater level (due to improved water drainage system), pine trees have returned the peat bog again. These results demonstrate that studies of subfossil bog-pine trees are quite effective in documenting and reconstructing periods of humidity fluctuation that occurred within the Carpathian region over the last several millennia.
•New site in Central Europe with subfossil bog pine (5415–2560 cal BP) is described.•Dendro-and multi-proxy studies allow to reconstruct climate fluctuations in last 5 ka.•Trees germination and dying-off phases are affected by palaeoecological changes.•Bog pine is very sensitive to hydrology and thermal conditions of the peatlands.
Lead pollution in Arctic ice reflects midlatitude emissions from ancient lead–silver mining and smelting. The few reported measurements have been extrapolated to infer the performance of ancient ...economies, including comparisons of economic productivity and growth during the Roman Republican and Imperial periods. These studies were based on sparse sampling and inaccurate dating, limiting understanding of trends and specific linkages. Here we show, using a precisely dated record of estimated lead emissions between 1100 BCE and 800 CE derived from subannually resolved measurements in Greenland ice and detailed atmospheric transport modeling, that annual European lead emissions closely varied with historical events, including imperial expansion, wars, and major plagues. Emissions rose coeval with Phoenician expansion, accelerated during expanded Carthaginian and Roman mining primarily in the Iberian Peninsula, and reached a maximum under the Roman Empire. Emissions fluctuated synchronously with wars and political instability particularly during the Roman Republic, and plunged coincident with two major plagues in the second and third centuries, remaining low for >500 years. Bullion in silver coinage declined in parallel, reflecting the importance of lead–silver mining in ancient economies. Our results indicate sustained economic growth during the first two centuries of the Roman Empire, terminated by the second-century Antonine plague.
We describe an ombrotrophic bog profile from Tinovul Mohoş, Eastern Carpathians, Romania to quantitatively reconstruct the hydroclimate and the palaeoecological evolution over the past 1000 years. ...Findings are based on high-resolution analyses of testate amoebae, plant macrofossils, pollen, micro- and macrocharcoal, δ13C stable carbon isotopes, organic matter content and bulk density, supported by AMS radiocarbon dating. We identify five major hydroclimatic intervals. Between AD 1050 and 1300, a wet period occurred associated with a time of reduced human population. Between AD 1300 and 1600, wet conditions continued to prevail, but with tendency towards drier mire settings. The third period from AD 1600–1680 revealed two abrupt disturbances in the local hydrology (strong dry-wet shifts). The fourth period, from AD 1680–1950, showed intermediate moist conditions with an increased humidity. After AD 1950, mire conditions became dry and there was an intensification in disturbances activity (forest clearance, fire and peatland drainage). Our multi-proxy reconstruction represents one of the few studies of the hydroclimate and palaeoecological evolution of the last millennium in the central-eastern Europe. Findings show good agreement with other hydroclimate reconstructions from this region, but not with records from north-western Europe. More high-resolution multi-proxy studies are needed to improve our understanding of the feedback mechanisms in peatlands and the factors behind these changes.
•A hydroclimate reconstruction is presented from an ombrotrophic mountain bog in Romania.•Five major hydroclimatic shifts are identified over the past 1000 years.•This dataset represents one of the few last millennium reconstructions from central-eastern Europe.•Good correlation exists with other palaeohydrological records from central eastern Europe.•Contrasting conditions with others estimates from northwest Europe.
A lack of information concerning the hydrology and hydrogeology of intact blanket bogs limits current understanding of how their alteration to mature forestry plantations impacts stream flow and ...associated water quality. An integrated hydrological/hydrogeological monitoring programme compared processes operating in a relatively intact blanket peat‐covered catchment with conditions encountered in an adjacent area under closed canopy plantation forestry. Groundwater monitoring revealed contrasting water level regimes and deeper summer water tables in the afforested area, with forest groundwater also having more elevated specific electrical conductance (SEC) and containing higher concentrations of dissolved organic carbon (DOC). Near‐simultaneous pairwise runoff sampling at the relatively intact catchment and afforested catchment outlets demonstrated no significant difference in DOC concentration. Conversely, water samples from the afforested catchment outlet displayed significantly greater SEC; this arose in part because of higher concentrations of dissolved calcium and magnesium, discharging via artificial drainage. Comparison of base flow runoff SEC with peat groundwater samples reflected in significant contrasts in ionic signature and greater levels of mineralisation in surface water, pointing to contributions of deeper water, derived from inorganic substrate materials. Study findings indicate that disturbance to the ground in that part of the catchment under plantation forestry has led to greater variations in stream flow and water quality for aquatic ecosystems. Comparable conditions have been observed instreams flowing through plantation forestry in similar physical settings elsewhere. Study findings suggest that plantations on deep peat can adversely affect stream ecosystems and this may impact on a water body's legal status.
The impact that mature plantation forestry on blanket peat has on stream flow, water quality and aquatic ecosystems is poorly understood. An integrated programme, investigating groundwater and surface water, compared conditions in an area of relatively‐intact open blanket bog with an adjacent area affected by plantation forestry. Study findings revealed that stream flow and surface water quality in the area under forestry proved more variable, giving rise to more variable abiotic supporting conditions for aquatic ecosystems.
ABSTRACT
Two conspicuous wet shifts in the peat stratigraphy of Store Mosse in southern Sweden, associated with bog‐wide changes in vegetation and degree of peat decomposition, were analysed at high ...resolution. The bog‐surface wetness (BSW) proxy data (organic matter bulk density, C/N ratio, plant macrofossils and testate amoebae) highlight the importance of interactions between vegetation composition, microtopography and degree of peat decomposition, and show that the bog system operated consistently during the two wet shifts (dated to c. 2700 and 1000 cal a
bp) despite different internal and external conditions. A sensitive bog‐system state, associated with a degraded microtopography and well‐decomposed surface peat with low hydrological conductivity developed during sustained dry conditions, probably contributed to the large BSW amplitudes registered. Comparable bog systems are expected to operate in the same way, and regionally high sensitivity that developed in response to atmospheric circulation changes may partly explain synchronous registration of wet shifts. The wet shifts in Store Mosse were attributed to solar and volcanic forcing, respectively, and wet shifts of similar magnitude registered in other NW European bogs are likely to also have been externally forced.
Permafrost peatlands store one‐third of the total carbon (C) in the atmosphere and are increasingly vulnerable to thaw as high‐latitude temperatures warm. Large uncertainties remain about C dynamics ...following permafrost thaw in boreal peatlands. We used a chronosequence approach to measure C stocks in forested permafrost plateaus (forest) and thawed permafrost bogs, ranging in thaw age from young (<10 years) to old (>100 years) from two interior Alaska chronosequences. Permafrost originally aggraded simultaneously with peat accumulation (syngenetic permafrost) at both sites. We found that upon thaw, C loss of the forest peat C is equivalent to ~30% of the initial forest C stock and is directly proportional to the prethaw C stocks. Our model results indicate that permafrost thaw turned these peatlands into net C sources to the atmosphere for a decade following thaw, after which post‐thaw bog peat accumulation returned sites to net C sinks. It can take multiple centuries to millennia for a site to recover its prethaw C stocks; the amount of time needed for them to regain their prethaw C stocks is governed by the amount of C that accumulated prior to thaw. Consequently, these findings show that older peatlands will take longer to recover prethaw C stocks, whereas younger peatlands will exceed prethaw stocks in a matter of centuries. We conclude that the loss of sporadic and discontinuous permafrost by 2100 could result in a loss of up to 24 Pg of deep C from permafrost peatlands.
The West Siberian Plain stands out among other boreal plains by phenomenal bogging, which has both global and regional significance. The polygonal bogs, frozen raised-mound bogs, and ombrotrophic ...ridge-hollow raised bogs are the most extensive bog types in the study area. These bogs commonly show highly diverse surface patterns consisting of mounds, polygons, ridges, hollows, and fens that correspond to the microtopes. Here we investigated how the microtopographic features of the landscape affect the thermal and hydrologic conditions of the soil as well as the nutrient availability and consequently, the dynamics of carbon and related elements. The effect of the surface heterogeneity on the temperature regimes and depths of permafrost is most significant. All of these factors together are reflected, through the feedback system, by a number of hydrochemical parameters of bog waters, such as dissolved organic and inorganic carbon (DOC, DIC), specific conductivity (Cond), SO42–, Cl–, P, Sr, Al, Ti, Cu, V, B, Cs, Cd, Rb, As, U, and rare earth elements (REEs). Among the studied parameters, DOC, SO42–, Al, V, and Mn differ most significantly between the convex and concave microforms. The DOC content in bog water is significantly affected by the water residence time, which is significantly longer in soils of mound/polygons than fens. Plants biomass is higher on the mounds which also have some effect that, due to leaching, should lead to more carbon entering into the water of the mounds. It is also shown that atmospheric-dust particles have a noticeable effect on the hydrochemical parameters of bog waters, especially on mounds. The ongoing climate warming will lead to an increase in the fens area and to a decrease in the content of DOC and many elements in bog waters.
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