The Distribution of Photoassimilated Carbon and the Growth of Douglas-fir Seedlings

Two-year-old Douglas-fir seedlings accumulated photoassimilated carbon in the tissues of new needles, previous years' needles, new shoots, stem, and roots at rates relative to tissue carbon of 1.25, 0.57, 0.42, 0.60, 0.61%/d, respectively. These daily net accumulation rates were measured just after bud set, and the rates parallel the carbon accumulation expected based on phenological observation. Results were obtained with a new system for long-term labelling of groups of seedlings with 14CO2 at a constant specific activity. This system is described.

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Modelling past, present and future peatland carbon accumulation across the pan-Arctic region

Biogeosciences ◽

10.5194/bg-14-4023-2017 ◽

2017 ◽

Vol 14 (18) ◽

pp. 4023-4044 ◽

Cited By ~ 21

Author(s):

Nitin Chaudhary ◽

Paul A. Miller ◽

Benjamin Smith

Keyword(s):

Carbon Sink ◽

Accumulation Rate ◽

Arctic Region ◽

Terrestrial Ecosystems ◽

Cold Climate ◽

Carbon Accumulation ◽

Accumulation Rates ◽

Eastern Canada ◽

The Holocene

Abstract. Most northern peatlands developed during the Holocene, sequestering large amounts of carbon in terrestrial ecosystems. However, recent syntheses have highlighted the gaps in our understanding of peatland carbon accumulation. Assessments of the long-term carbon accumulation rate and possible warming-driven changes in these accumulation rates can therefore benefit from process-based modelling studies. We employed an individual-based dynamic global ecosystem model with dynamic peatland and permafrost functionalities and patch-based vegetation dynamics to quantify long-term carbon accumulation rates and to assess the effects of historical and projected climate change on peatland carbon balances across the pan-Arctic region. Our results are broadly consistent with published regional and global carbon accumulation estimates. A majority of modelled peatland sites in Scandinavia, Europe, Russia and central and eastern Canada change from carbon sinks through the Holocene to potential carbon sources in the coming century. In contrast, the carbon sink capacity of modelled sites in Siberia, far eastern Russia, Alaska and western and northern Canada was predicted to increase in the coming century. The greatest changes were evident in eastern Siberia, north-western Canada and in Alaska, where peat production hampered by permafrost and low productivity due the cold climate in these regions in the past was simulated to increase greatly due to warming, a wetter climate and higher CO2 levels by the year 2100. In contrast, our model predicts that sites that are expected to experience reduced precipitation rates and are currently permafrost free will lose more carbon in the future.

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Carbon accumulation rates in two poor fens with different water regimes: Influence of anthropogenic impact and environmental change

The Holocene ◽

10.1177/0959683614544062 ◽

2014 ◽

Vol 24 (11) ◽

pp. 1539-1549 ◽

Cited By ~ 11

Author(s):

Barbara Fiałkiewicz-Kozieł ◽

Beata Smieja-Król ◽

Natalia Piotrowska ◽

Jarosław Sikorski ◽

Mariusz Gałka

Keyword(s):

Promising Result ◽

Bulk Composition ◽

Mean Value ◽

Carbon Accumulation ◽

Ice Age ◽

Accumulation Rates ◽

Boreal Peatlands ◽

The Mean ◽

Carbon Accumulation Rates

Fens are underestimated carbon sinks. Knowledge about their role in the sequestration of CO2 in the past is limited. The research reported here focused on identifying long-term carbon accumulation rates (CARs) in a drained fen (Bagno Bruch) and a waterlogged fen (Bagno Mikołeska) in southern Poland. On the basis of 210Pb and AMS 14C dates and age–depth modeling, 7000- and 2000-year records of changes in bulk composition and carbon and sulfur content are presented and discussed. Strong human impact is detected, especially in Bagno Bruch. However, minor climatic signals linked to the ‘Little Ice Age’ and to the influence of wind-blown sands are also evident. The sand may have influenced the plant composition, peat accumulation rates (PARs), and CARs, in addition to the bulk composition at Bagno Mikołeska. The mean value of the CAR in the youngest peat layers spanning the last 200 years is generally lower in two cores from Bagno Bruch ( c. 85 and 86 g/m2/yr) than in two cores from Bagno Mikołeska ( c. 140 and 142 g/m2/yr). The fens are characterized by higher CARs compared with boreal peatlands. The reproducibility of the CAR values is the most promising result, suggesting the low mobility of 210Pb and the reliability of this method in assessing the chronology of fens.

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Carbon accumulation rates of Holocene peatlands in central-eastern Europe document the driving role of human impact for the past 4000 years

10.5194/cp-2021-65 ◽

2021 ◽

Author(s):

Jack Longman ◽

Daniel Veres ◽

Aritina Haliuc ◽

Walter Finsinger ◽

Vasile Ersek ◽

...

Keyword(s):

Eastern Europe ◽

Human Impact ◽

Anthropogenic Impact ◽

Carbon Sink ◽

Carbon Accumulation ◽

Accumulation Rates ◽

Central Eastern Europe ◽

Central Eastern ◽

Carbon Accumulation Rates

Abstract. Peatlands are one of the largest terrestrial carbon sinks on the planet, yet little is known about carbon accumulation rates (CARs) of mountainous examples. The long-term variability in the size of the associated carbon sink and its drivers remain largely unconstrained, especially when long-term anthropogenic impact is also considered. Here we present a composite CAR record of nine peatlands from central-eastern Europe (Romania and Serbia) detailing variability in rates of carbon accumulation across the Holocene. We show examples of extremely high long-term rates of carbon accumulation (LORCA > 120 g C m−2 yr−1), indicating that at times, mountain peatlands constitute an efficient regional carbon sink. By comparing our data to modelled palaeoclimatic indices and to measures of anthropogenic impact we disentangle the drivers of peat carbon accumulation in the area. Variability in early and mid-Holocene CARs is linked to hydroclimatic controls, with high CARs occurring during the early Holocene and lower CARs associated with the transition to cooler and moister mid-Holocene conditions. By contrast, after 4000 years (calibrated) before present (yr BP) the trends in CARs indicate a divergence from hydroclimate proxies, indicating that other processes became the dominant drivers of peat CARs. We suggest that enhanced erosion following tree cover reduction as well as enhanced rates of long-distance atmospheric dust fallout might have played a role as both processes would result in enhanced mineral and nutrient supply to bog surfaces, stimulating peat land productivity. Surprisingly though, for the last 1000 years, reconstructed temperature is significantly correlated with CARs, with rising temperatures linked to higher CARs. We suggest under future climate conditions, predicted to be warmer in the region, peat growth may expand, but that this is entirely dependent upon the scale of human impact directly affecting the sensitive hydrological budget of these peatlands.

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Greenhouse climate forces expansion of peatlands into inland areas

10.5194/egusphere-egu2020-3988 ◽

2020 ◽

Author(s):

Zhihui Zhang ◽

Chengshan Wang ◽

Dawei Lv ◽

Tiantian Wang

Keyword(s):

Natural Science ◽

Middle Jurassic ◽

Carbon Pool ◽

Carbon Accumulation ◽

Accumulation Rates ◽

High Carbon ◽

Geological Time ◽

Greenhouse Climate ◽

Carbon Reservoir

<p>As a significant terrestrial carbon reservoir, peatland has great potential to affect the global carbon cycle and global climate. However, our understanding of broad-scale mechanisms that control the long-term global peatland expansion and carbon accumulation rates is still limited. Here we present a new data synthesis of global coal deposit location, thickness changes, carbon concentration, and distribution area changes, along with new carbon pool estimates of global peatlands from Devonian through geological time. By identifying orbital cycles in coal seams, we show that the long-term rate of carbon accumulation (LORCA) in peatland calculated from published data is controlled by <em>p</em>O<sub>2</sub>, <em>p</em>CO<sub>2</sub>, temperature, precipitation, and total solar irradiance. We use this relationship and latitudinal temperature gradients to reconstruct the equations between LORCA with latitude on different geological time. The results suggest that there are three main sets of high carbon pool and high carbon accumulation rate of global peatlands in Late Paleozoic, Early-Middle Jurassic, and Late-Cretaceous to Early Cenozoic under low tectonic activity and high terrestrial plant diversity background. In addition, we measure the shortest distances between all coal locations and coastlines based on the new Scotese&#8217;s paleo-Atlas for the past 400 million years, in order to exhibit the extent of peatland expansion into inland. The result shows the Early-Middle Jurassic period has the longest average distance, which is probably due to the high sea level that minimizes the development of peat swamps on coastal areas and facilitated the moisture to move into deeper inland under the Jurassic Greenhouse climate condition. This study highlights that combining comprehensive coal-related database with paleoclimate, tectonics, and evolution of land plants provides insights into the mechanisms of the long-term behavior of the peatland expansion and carbon reservoir through deep time.</p><p>Keywords: Greenhouse climate, Peatland expansion, Carbon pool, Cabon accumulation rates, Coal</p><div> <div> <div> <p>This study wasfinancially supported by the National Natural Science Foundation of China (grant No. 41888101), the National Key R&D Plan of China (grant No. 2017YFC0601405) and the National Natural Science Foundation of China (grants 41790450, 41772096).</p> </div> </div> </div>

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Local Spatial Heterogeneity of Holocene Carbon Accumulation throughout the Peat Profile of an Ombrotrophic Northern Minnesota Bog

Radiocarbon ◽

10.1017/rdc.2018.37 ◽

2018 ◽

Vol 60 (3) ◽

pp. 941-962 ◽

Cited By ~ 5

Author(s):

Karis J McFarlane ◽

Paul J Hanson ◽

Colleen M Iversen ◽

Jana R Phillips ◽

Deanne J Brice

Keyword(s):

Spatial Heterogeneity ◽

Carbon Accumulation ◽

Experimental Warming ◽

Accumulation Rates ◽

Boreal Peatlands ◽

Aerobic Decomposition ◽

Peat Profile ◽

Carbon Accumulation Rates ◽

Plot Location

ABSTRACTWe evaluated the spatial heterogeneity of historical carbon accumulation rates in a forested, ombrotrophic bog in Minnesota to aid understanding of responses to an ongoing decade-long warming manipulation. Eighteen peat cores indicated that the bog has been accumulating carbon for over 11,000 years, to yield 176±40 kg C m−2 to 225±58 cm of peat depth. Estimated peat basal ages ranged from 5100 to 11,100 cal BP. The long-term apparent rate of carbon accumulation over the entire peat profile was 22±2 kg C m−2 yr−1. Plot location within the study area did not affect carbon accumulation rates, but estimated basal ages were younger in profiles from plots closer to the bog lagg and farther from the bog outlet. In addition, carbon accumulation varied considerably over time. Early Holocene net carbon accumulation rates were 30±6 g C m−2 yr−1. Around 3300 calendar BP, net carbon accumulation rates dropped to 15±8 g C m−2 yr−1 until the last century when net accumulation rates increased again to 74±57 g C m−2 yr−1. During this period of low accumulation, regional droughts may have lowered the water table, allowing for enhanced aerobic decomposition and making the bog more susceptible to fire. These results suggest that experimental warming treatments, as well as a future warmer climate may reduce net carbon accumulation in peat in this and other southern boreal peatlands. Furthermore, our we caution against historical interpretations extrapolated from one or a few peat cores.

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Estimating Long-Term Carbon Accumulation Rates in Boreal Peatlands by Radiocarbon Dating

Radiocarbon ◽

10.1017/s0033822200031064 ◽

1995 ◽

Vol 37 (2) ◽

pp. 575-584 ◽

Cited By ~ 35

Author(s):

Atte Korhola ◽

Kimmo Tolonen ◽

Jukka Turunen ◽

Högne Jungner

Keyword(s):

Carbon Accumulation ◽

Accumulation Rates ◽

Raised Bog ◽

Constant Input ◽

Wetland Type ◽

Land Uplift ◽

Radiocarbon Dates ◽

Boreal Peatlands ◽

Carbon Accumulation Rates

We used direct radiocarbon dates of peat samples, pollen dates and land-uplift chronology from >1300 cores comprising all or most of the Holocene in the boreal region of Finland, Estonia and Maine (USA) to obtain long-term carbon accumulation rates for boreal peatlands. The “apparent” long-term rate of carbon accumulation (LORCA; g C m−2 a−1) ranged from 4.6 to 85.8 (mean 19.9 ± 10.7), depending on the geographical location, wetland type and the age of the mire. The “true” or “actual” rate of carbon accumulation (ARCA), as derived from models for peatbog growth, was usually ca. 70% of LORCA. We studied the raised bog Reksuo more intensely in terms of growth dynamics, and we report preliminary results of the “three-dimensional” or spatial carbon accumulation rates. These results strongly contradict the concept of constant input and constant decay throughout the millennia. The study emphasizes the importance of exploring the formation and dynamics of entire mire ecosystems, and the role of carbon in these systems, in addition to studying single cores.

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Peatland formation, succession and carbon accumulation at a mid-elevation poor fen in Pacific Canada

The Holocene ◽

10.1177/0959683619862041 ◽

2019 ◽

Vol 29 (11) ◽

pp. 1694-1707

Author(s):

Terri Lacourse ◽

Matthew A Adeleye ◽

Johanna R Stewart

Keyword(s):

British Columbia ◽

Carbon Accumulation ◽

Early Holocene ◽

Plant Functional Groups ◽

Accumulation Rates ◽

Poor Fen ◽

Relative Water ◽

Lateral Extent ◽

Coastal British Columbia

We reconstructed peatland formation, succession and long-term rates of carbon (C) accumulation at a mid-elevation poor fen on Vancouver Island in coastal British Columbia, Canada. Multi-proxy paleoecological analyses including bulk chemistry, peat composition, macrofossils, pollen and non-pollen palynomorphs show terrestrialization starting from a small oligotrophic lake 14,000 cal BP. Peat accumulation began by 11,600 cal BP with the transition to an emergent Nuphar-dominated shallow-water marsh. Terrestrialization in the center of the peatland was more or less complete by 10,400 cal BP with the development of a Sphagnum-dominated poor fen that continues to the present. Outward expansion by paludification appears to have brought the peatland close to its modern lateral extent by 10,000 cal BP, suggesting that terrestrialization and paludification played important concurrent roles in the early development of this poor fen. Mean long-term rates of C accumulation (13 g C/m2/yr) are lower than at most Northern Hemisphere peatlands including nearby lowland bogs. Maximum rates of 43 g C/m2/yr occurred in the early Holocene during accumulation of Nuphar peat and the transition to Sphagnum peat and coincided with high summer temperatures and increased seasonality, which promote growing season productivity and reduce winter decomposition. Early Holocene increases in C accumulation rates occurred at two nearby lowland bogs during similar wetland stages. Collectively, these studies demonstrate that climate and autogenic succession, including changes in relative water table depth and plant functional groups, interacted to drive Holocene peatland dynamics and C accumulation rates in the maritime setting of coastal British Columbia.

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Modelling past, present and future peatland carbon accumulation across the pan-Arctic

10.5194/bg-2017-34 ◽

2017 ◽

Author(s):

Nitin Chaudhary ◽

Paul A. Miller ◽

Benjamin Smith

Keyword(s):

Carbon Sink ◽

Accumulation Rate ◽

Far East ◽

Terrestrial Ecosystems ◽

Cold Climate ◽

Carbon Accumulation ◽

Accumulation Rates ◽

Eastern Canada ◽

The Holocene

Abstract. Most northern peatlands developed during the Holocene, sequestering large amounts of carbon in terrestrial ecosystems. However, recent syntheses have highlighted the gaps in our understanding of peatland carbon accumulation. Assessments of the long-term carbon accumulation rate and possible warming driven changes in these accumulation rates can therefore benefit from process-based modelling studies. We employed an individual- and patch-based dynamic global ecosystem model with dynamic peatland and permafrost functionality and vegetation dynamics to quantify long-term carbon accumulation rates and to assess the effects of historical and projected climate change on peatland carbon balances across the pan-Arctic. Our results are broadly consistent with published regional and global carbon accumulation estimates. A majority of modelled peatland sites in Scandinavia, Europe, Russia and Central and eastern Canada change from carbon sinks through the Holocene to potential carbon sources in the coming century. In contrast, the carbon sink capacity of modelled sites in Siberia, Far East Russia, Alaska and western and northern Canada was predicted to increase in the coming century. The greatest changes were evident in eastern Siberia, northwest Canada and in Alaska, where peat production, from being hampered by permafrost and low productivity due the cold climate in these regions in the past, was simulated to increase greatly due to warming, wetter climate and greater CO2 levels by the year 2100. In contrast, our model predicts that sites that are expected to experience reduced precipitation rates and are currently permafrost free will lose more carbon in the future.

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Misinterpreting carbon accumulation rates in records from near-surface peat

Scientific Reports ◽

10.1038/s41598-019-53879-8 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 7

Author(s):

Dylan M. Young ◽

Andy J. Baird ◽

Dan J. Charman ◽

Chris D. Evans ◽

Angela V. Gallego-Sala ◽

...

Keyword(s):

Land Use ◽

Land Use Policy ◽

Carbon Accumulation ◽

Accumulation Rates ◽

Near Surface ◽

Carbon Accumulation Rates ◽

Surface Peat ◽

Land Use Practices ◽

Over Time

AbstractPeatlands are globally important stores of carbon (C) that contain a record of how their rates of C accumulation have changed over time. Recently, near-surface peat has been used to assess the effect of current land use practices on C accumulation rates in peatlands. However, the notion that accumulation rates in recently formed peat can be compared to those from older, deeper, peat is mistaken – continued decomposition means that the majority of newly added material will not become part of the long-term C store. Palaeoecologists have known for some time that high apparent C accumulation rates in recently formed peat are an artefact and take steps to account for it. Here we show, using a model, how the artefact arises. We also demonstrate that increased C accumulation rates in near-surface peat cannot be used to infer that a peatland as a whole is accumulating more C – in fact the reverse can be true because deep peat can be modified by events hundreds of years after it was formed. Our findings highlight that care is needed when evaluating recent C addition to peatlands especially because these interpretations could be wrongly used to inform land use policy and decisions.

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Reviews and syntheses: <sup>210</sup>Pb-derived sediment and carbon accumulation rates in vegetated coastal ecosystems – setting the record straight

Biogeosciences ◽

10.5194/bg-15-6791-2018 ◽

2018 ◽

Vol 15 (22) ◽

pp. 6791-6818 ◽

Cited By ~ 26

Author(s):

Ariane Arias-Ortiz ◽

Pere Masqué ◽

Jordi Garcia-Orellana ◽

Oscar Serrano ◽

Inés Mazarrasa ◽

...

Keyword(s):

Specific Activity ◽

210Pb Dating ◽

Coastal Ecosystems ◽

Carbon Accumulation ◽

Coastal Sediments ◽

Tidal Marshes ◽

Accumulation Rates ◽

Seagrass Meadows ◽

Sediment Organic Carbon ◽

Heterogeneous Sediments

Abstract. Vegetated coastal ecosystems, including tidal marshes, mangroves and seagrass meadows, are being increasingly assessed in terms of their potential for carbon dioxide sequestration worldwide. However, there is a paucity of studies that have effectively estimated the accumulation rates of sediment organic carbon (Corg), also termed blue carbon, beyond the mere quantification of Corg stocks. Here, we discuss the use of the 210Pb dating technique to determine the rate of Corg accumulation in these habitats. We review the most widely used 210Pb dating models to assess their limitations in these ecosystems, often composed of heterogeneous sediments with varying inputs of organic material, that are disturbed by natural and anthropogenic processes resulting in sediment mixing and changes in sedimentation rates or erosion. Through a range of simulations, we consider the most relevant processes that impact the 210Pb records in vegetated coastal ecosystems and evaluate how anomalies in 210Pb specific activity profiles affect sediment and Corg accumulation rates. Our results show that the discrepancy in sediment and derived Corg accumulation rates between anomalous and ideal 210Pb profiles is within 20 % if the process causing such anomalies is well understood. While these discrepancies might be acceptable for the determination of mean sediment and Corg accumulation rates over the last century, they may not always provide a reliable geochronology or historical reconstruction. Reliable estimates of Corg accumulation rates might be difficult at sites with slow sedimentation, intense mixing and/or that are affected by multiple sedimentary processes. Additional tracers or geochemical, ecological or historical data need to be used to validate the 210Pb-derived results. The framework provided in this study can be instrumental in reducing the uncertainties associated with estimates of Corg accumulation rates in vegetated coastal sediments.

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