Misinterpreting carbon accumulation rates in records from near-surface peat

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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Constructive criticism of “Misinterpreting carbon accumulation rates in records from near-surface peat” by Young et al: Further evidence of charcoal impacts in relation to long-term carbon storage on blanket bog under rotational burn management

10.32942/osf.io/t4g3m ◽

2021 ◽

Author(s):

Andreas Heinemeyer ◽

Mark Andrew Ashby

Keyword(s):

Carbon Accumulation ◽

Accumulation Rates ◽

Near Surface ◽

Core Data ◽

Peat Core ◽

Blanket Bog ◽

The Impact ◽

Carbon Accumulation Rates ◽

Surface Peat ◽

Model Scenarios

t is with great interest that we read the recent paper by Young et al. entitled “Misinterpreting carbon accumulation rates in records from near-surface peat”. However, we have some concerns about: (i) the use of an unvalidated deep drainage model to criticise studies investigating the impact of heather burning; (ii) the model scenarios and underlying model assumptions used; and (iii) misleading claims made about net C budgets and deep C losses. We feel that these issues require clarification and, in some cases, correction, especially as Young et al. has been used by a leading peatland policy and conservation body (IUCN UK Peatland Programme) to incorrectly characterise two recent studies by Heinemeyer et al. and Marrs et al. as having “presented misleading conclusions”. We strongly believe that one of the main ways to increase our scientific understanding is through vigorous and factual debate. Whilst we are open to and welcome criticism, such criticism needs to be accurate, balanced and evidence-based. Criticism must avoid unfounded or speculative accusations, especially when based on unrelated and unvalidated model scenarios. Indeed, study aims, hypotheses and discussion sections all need to be considered to ensure any criticism is applicable. We accept that deep C losses can be caused by peatland drainage and that this can lead to the misinterpretation of peat surface C accumulation rates or peatland C budgets. But these issues do not apply to the Heinemeyer et al. study, which investigated two specific and clearly stated burn-related hypotheses (charcoal impacts on peat properties and thus peat C accumulation), which only required comparisons of C accumulation rates within recent peat layers. Moreover, using peat core data collected by Heinemeyer et al., we provide strong evidence that the accusations of deep C losses by Young et al. are unfounded. However, the peat core data from Heinemeyer et al. does highlight the value of the Young et al. model scenarios for predicting short-term C loss caused by recent drainage. Finally, we also highlight the value of a detailed peat layer organic C content (%Corg) assessments to detect potential management (i.e. drainage) induced deep peat C loss.

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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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Relationships between environmental governance and water quality in growing metropolitan areas: a synthetic view through the coupled natural and human system lens

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-10-7395-2013 ◽

2013 ◽

Vol 10 (6) ◽

pp. 7395-7424 ◽

Cited By ~ 2

Author(s):

H. Chang ◽

P. Thiers ◽

N. R. Netusil ◽

J. A. Yeakley ◽

G. Rollwagen-Bollens ◽

...

Keyword(s):

Water Quality ◽

Land Use ◽

Environmental Governance ◽

Metropolitan Areas ◽

Water Governance ◽

Land Development ◽

Land Use Policy ◽

Riparian Restoration ◽

Over Time

Abstract. We investigate relationships between environmental governance and water quality in two adjacent, growing metropolitan areas in the western US. While the Portland, Oregon and Vancouver, Washington metro areas share many biophysical characteristics, they have different land development histories and water governance structures, providing a unique opportunity for examining a coupled human and natural system (CHANS). We conceptualize feedback loops in which water quality influences governance directly, using monitoring efforts as a metric, and indirectly, using the metric of changes in the sale price of single-family residential properties. Governance then influences water quality directly through, for example, changes in the monitoring regime and riparian restoration and indirectly through land use policy. We investigate these hypotheses by presenting evidence of these linkages. Our results show that changes in monitoring regimes and land use differed in response to differences in governance systems. On the other hand, property sale prices increased in response to water quality improvement for both studied watersheds. Our results show that sales prices responded positively to improved water quality (i.e. DO) in both cities. Furthermore, riparian restoration efforts improved over time for both cities, indicating the positive effect of governance on this land-based resource that may result in improved water quality. However, as of yet, there were no substantial differences across study areas in changes in water temperature over time. While urban areas expanded more than 20% over 24 yr, water temperature did not change. The mechanisms by which water quality was maintained was similar in the sense that both cities benefited from riparian restoration, but different in the sense that Portland benefitted indirectly from land use policy. A combination of a long-term legacy effect of land development and a relatively short history of riparian restoration in both the Portland and Vancouver regions may have masked any subtle differences in both regions. An alternative explanation is that both cities exhibited combinations of positive indirect and direct water quality governance that resulted in maintenance of water quality in the face of increased urban growth. These findings suggest that a long-term water quality monitoring effort is needed to identify the effectiveness of alternative land development and water governance policies.

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Sedimentation and belowground carbon accumulation rates in mangrove forests that differ in diversity and land use: a tale of two mangroves

Wetlands Ecology and Management ◽

10.1007/s11273-016-9481-3 ◽

2016 ◽

Vol 24 (2) ◽

pp. 245-261 ◽

Cited By ~ 24

Author(s):

Richard A. MacKenzie ◽

Patra B. Foulk ◽

J. Val Klump ◽

Kimberly Weckerly ◽

Joko Purbospito ◽

...

Keyword(s):

Land Use ◽

Carbon Accumulation ◽

Mangrove Forests ◽

Accumulation Rates ◽

Belowground Carbon ◽

Carbon Accumulation Rates

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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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Land-Use Intensity Effects on Soil Organic Carbon Accumulation Rates and Mechanisms

Ecosystems ◽

10.1007/s10021-006-9010-y ◽

2007 ◽

Vol 10 (1) ◽

pp. 59-74 ◽

Cited By ~ 231

Author(s):

A. Stuart Grandy ◽

G. Philip Robertson

Keyword(s):

Land Use ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Accumulation ◽

Land Use Intensity ◽

Accumulation Rates ◽

Carbon Accumulation Rates

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

Climate of the Past ◽

10.5194/cp-17-2633-2021 ◽

2021 ◽

Vol 17 (6) ◽

pp. 2633-2652

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 the carbon accumulation rates (CARs) of mountainous peatlands. The long-term variability in the size of the associated carbon sink and its drivers remain largely unconstrained, especially when the 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 the rates of carbon accumulation during the Holocene. We show examples of extremely high long-term rates of carbon accumulation (LORCA>120 gCm-2yr-1), indicating that mountain peatlands constitute an efficient regional carbon sink at times. 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 (years BP), the trends in CARs indicate a divergence from hydroclimate proxies, suggesting that other processes became the dominant drivers of peat CARs. We propose that enhanced erosion following tree cover reduction as well as increased 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 peatland productivity. Surprisingly though, for the last 1000 years, reconstructed temperature is significantly correlated with CARs, with rising temperatures linked to higher CARs. Under future climate conditions, which are predicted to be warmer in the region, we predict that 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.

Download Full-text