scholarly journals The browning and re-browning of lakes: Divergent lake-water organic carbon trends linked to acid deposition and climate change

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Carsten Meyer-Jacob ◽  
Neal Michelutti ◽  
Andrew M. Paterson ◽  
Brian F. Cumming ◽  
Wendel (Bill) Keller ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Acid Deposition ◽  
Lake Water ◽  
Spectroscopic Techniques ◽  
Central Canada ◽  
Atmospheric Acid Deposition ◽  
Aquatic Productivity ◽  
Productivity Potential

Abstract Dissolved organic carbon (DOC) concentrations and water colour are increasing in many inland waters across northern Europe and northeastern North America. This inland-water “browning” has profound physical, chemical and biological repercussions for aquatic ecosystems affecting water quality, biological community structures and aquatic productivity. Potential drivers of this “browning” trend are complex and include reductions in atmospheric acid deposition, changes in land use/cover, increased nitrogen deposition and climate change. However, because of the overlapping impacts of these stressors, their relative contributions to DOC dynamics remain unclear, and without appropriate long-term monitoring data, it has not been possible to determine whether the ongoing “browning” is unprecedented or simply a “re-browning” to pre-industrial DOC levels. Here, we demonstrate the long-term impacts of acid deposition and climate change on lake-water DOC concentrations in low and high acid-deposition areas using infrared spectroscopic techniques on ~200-year-long lake-sediment records from central Canada. We show that acid deposition suppressed naturally higher DOC concentrations during the 20th century, but that a “re-browning” of lakes is now occurring with emissions reductions in formerly high deposition areas. In contrast, in low deposition areas, climate change is forcing lakes towards new ecological states, as lake-water DOC concentrations now often exceed pre-industrial levels.

scholarly journals Differential long-term effects of climate change and management on stocks and distribution of soil organic carbon in productive grasslands

2012 ◽  
Vol 9 (1) ◽  
pp. 1055-1096 ◽  
Author(s):  
A. M. G. De Bruijn ◽  
P. Calanca ◽  
C. Ammann ◽  
J. Fuhrer
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Climate Change Scenarios ◽  
Long Term Effects ◽  
Organic C ◽  
Soil C ◽  
The Impact ◽  
Soc Stocks

Abstract. We studied the impact of climate change on the dynamics of soil organic carbon (SOC) stocks in productive grassland systems undergoing two types of management, an intensive type with frequent harvests and fertilizer applications and an extensive system where fertilization is omitted and harvests are fewer. The Oensingen Grassland Model was explicitly developed for this study. It was calibrated using measurements taken in a recently established permanent sward in Central Switzerland, and run to simulate SOC dynamics over 2001–2100 under three climate change scenarios assuming different elements of IPCC A2 emission scenarios. We found that: (1) management intensity dominates SOC until approximately 20 yr after grassland establishment. Differences in SOC between climate scenarios become significant after 20 yr and climate effects dominate SOC dynamics from approximately 50 yr after establishment, (2) carbon supplied through manure contributes about 60% to measured organic C increase in fertilized grassland. (3) Soil C accumulates particularly in the top 10 cm soil until 5 yr after establishment. In the long-term, C accumulation takes place in the top 15 cm of the soil profile, while C content decreases below this depth. The transitional depth between gains and losses of C mainly depends on the vertical distribution of root senescence and root biomass. We discuss the importance of previous land use on carbon sequestration potentials that are much lower at the Oensingen site under ley-arable rotation and with much higher SOC stocks than most soils under arable crops. We further discuss the importance of biomass senescence rates, because C balance estimations indicate that these may differ considerably between the two management systems.

scholarly journals Drivers of Dissolved Organic Carbon Mobilization From Forested Headwater Catchments: A Multi Scaled Approach

2021 ◽  
Vol 3 ◽  
Author(s):  
Thomas Adler ◽  
Kristen L. Underwood ◽  
Donna M. Rizzo ◽  
Adrian Harpold ◽  
Gary Sterle ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Acid Deposition ◽  
Iterative Process ◽  
Catchment Scale ◽  
Regional Patterns ◽  
Headwater Catchments ◽  
Catchment Characteristics ◽  
Pattern Approach

Understanding and predicting catchment responses to a regional disturbance is difficult because catchments are spatially heterogeneous systems that exhibit unique moderating characteristics. Changes in precipitation composition in the Northeastern U.S. is one prominent example, where reduction in wet and dry deposition is hypothesized to have caused increased dissolved organic carbon (DOC) export from many northern hemisphere forested catchments; however, findings from different locations contradict each other. Using shifts in acid deposition as a test case, we illustrate an iterative “process and pattern” approach to investigate the role of catchment characteristics in modulating the steam DOC response. We use a novel dataset that integrates regional and catchment-scale atmospheric deposition data, catchment characteristics and co-located stream Q and stream chemistry data. We use these data to investigate opportunities and limitations of a pattern-to-process approach where we explore regional patterns of reduced acid deposition, catchment characteristics and stream DOC response and specific soil processes at select locations. For pattern investigation, we quantify long-term trends of flow-adjusted DOC concentrations in stream water, along with wet deposition trends in sulfate, for USGS headwater catchments using Seasonal Kendall tests and then compare trend results to catchment attributes. Our investigation of climatic, topographic, and hydrologic catchment attributes vs. directionality of DOC trends suggests soil depth and catchment connectivity as possible modulating factors for DOC concentrations. This informed our process-to-pattern investigation, in which we experimentally simulated increased and decreased acid deposition on soil cores from catchments of contrasting long-term DOC response [Sleepers River Research Watershed (SRRW) for long-term increases in DOC and the Susquehanna Shale Hills Critical Zone Observatory (SSHCZO) for long-term decreases in DOC]. SRRW soils generally released more DOC than SSHCZO soils and losses into recovery solutions were higher. Scanning electron microscope imaging indicates a significant DOC contribution from destabilizing soil aggregates mostly from hydrologically disconnected landscape positions. Results from this work illustrate the value of an iterative process and pattern approach to understand catchment-scale response to regional disturbance and suggest opportunities for further investigations.

Re-browning of Sudbury (Ontario, Canada) lakes now approaches pre-acid deposition lake-water dissolved organic carbon levels

2020 ◽  
Vol 725 ◽  
pp. 138347 ◽  
Author(s):  
Carsten Meyer-Jacob ◽  
Andrew L. Labaj ◽  
Andrew M. Paterson ◽  
Brie A. Edwards ◽  
Wendel (Bill) Keller ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Acid Deposition ◽  
Lake Water

scholarly journals Differential long-term effects of climate change and management on stocks and distribution of soil organic carbon in productive grasslands

2012 ◽  
Vol 9 (6) ◽  
pp. 1997-2012 ◽  
Author(s):  
A. M. G. De Bruijn ◽  
P. Calanca ◽  
C. Ammann ◽  
J. Fuhrer
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Climate Change Scenarios ◽  
Long Term Effects ◽  
Organic C ◽  
Soil C ◽  
The Impact ◽  
Soc Stocks

Abstract. We studied the impact of climate change on the dynamics of soil organic carbon (SOC) stocks in productive grassland systems undergoing two types of management, an intensive type with frequent harvests and fertilizer applications and an extensive system without fertilization and fewer harvests. Simulations were conducted with a dedicated newly developed model, the Oensingen Grassland Model. It was calibrated using measurements taken in a recently established permanent sward in Central Switzerland, and run to simulate SOC dynamics over 2001–2100 under various climate change scenarios assuming different elements of IPCC A2 emission scenarios. We found that: (1) management intensity dominates SOC until approximately 20 years after grassland establishment. Differences in SOC between climate scenarios become significant after 20 years and climate effects dominate SOC dynamics from approximately 50 years after establishment. (2) Carbon supplied through manure contributes about 60 % to measured organic C increase in fertilized grassland. (3) Soil C accumulates particularly in the top 10 cm of the soil until 5 years after establishment. In the long-term, C accumulation takes place in the top 15 cm of the soil profile, while C content decreases below this depth. The transitional depth between gains and losses of C mainly depends on the vertical distribution of root senescence and root biomass. We discuss the importance of previous land use on carbon sequestration potentials that are much lower at the Oensingen site under ley-arable rotation with much higher SOC stocks than most soils under arable crops. We further discuss the importance of biomass senescence rates, because C balance estimations indicate that these may differ considerably between the two management systems.

How useful are MIR predictions of total, particulate, humus, and resistant organic carbon for examining changes in soil carbon stocks in response to different crop management? A case study

Soil Research ◽  
2013 ◽  
Vol 51 (8) ◽  
pp. 719 ◽  
Author(s):  
K. L. Page ◽  
R. C. Dalal ◽  
Y. P. Dang
Keyword(s):  
Organic Carbon ◽  
Soil Carbon ◽  
Management Practices ◽  
Crop Management ◽  
Carbon Stocks ◽  
Carbon Pools ◽  
Spectroscopic Techniques ◽  
Direct Measurements ◽  
Soil Carbon Stocks

Measures of particulate organic carbon (POC), humus organic carbon (HOC), and resistant organic carbon (ROC) (primarily char) are often used to represent the active, slow, and inert carbon pools used in soil carbon models. However, these fractions are difficult to measure directly, and mid infrared (MIR) spectroscopic techniques are increasingly being investigated to quantify these fractions and total organic carbon (TOC). This study examined the change in MIR-predicted pools of TOC, POC, HOC, and ROC in response to different crop management between two time periods (1981 and 2008) in a long-term wheat cropping trial in Queensland, Australia. The aims were (i) to assess the ability of MIR to detect changes in carbon stocks compared with direct measurements of TOC (LECO-TOC); and (ii) to assess how well the behaviour of POC, HOC, and ROC corresponded with the active, slow, and inert conceptual carbon pools. Significant declines in carbon stocks were observed over time using both LECO-TOC and MIR-predicted stocks of TOC, POC, HOC, and ROC, although MIR-TOC under-estimated loss by 27–30% compared with LECO-TOC. The decline in MIR-POC and MIR-HOC was consistent with the expected behaviour of the active and slow conceptual pools; however, the decline in ROC was not consistent with that of the inert pool. In addition, MIR measurements did not accurately detect differences in the rate of carbon loss under different crop management practices.

scholarly journals Comparison of Topsoil Organic Carbon Stocks on Slopes under Soil-Protecting Forests in Relation to the Adjacent Agricultural Slopes

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 390
Author(s):  
Paweł Wiśniewski ◽  
Michael Märker
Keyword(s):  
Climate Change ◽  
Soil Erosion ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Organic Matter Content ◽  
Carbon Stocks ◽  
Matter Content ◽  
Soil Organic Carbon Pools ◽  
Production Areas

Soil erosion is one of the major processes degrading the natural environment but also agricultural production areas. Soil erosion may lead to soil organic carbon (SOC) loss, especially from sloping agricultural terrain units. The use of phytomelioration in environmental management, particularly long-term, permanent forest vegetation, is widely recognized as a possible measure for soil erosion protection and mitigation of climate change through carbon sequestration. The aim of this study was to compare of the topsoil organic carbon stocks on the slopes under soil-protecting forests in relation to the adjacent agricultural slopes. The research was conducted in the young glacial landscape of North-Central Poland. The study indicated the significant role of forest management on the increase of soil organic matter content and SOC stock. The results show that land use and slope gradients are important factors controlling soil organic carbon pools in topsoil in young glacial areas. This topic is extremely important particularly as the effects of climate change become more and more visible, and society faces new challenges in preventing these changes.

scholarly journals Providing a long-term hydroclimatic perspective for the recent extreme decline of Lake Prespa (SW Balkans) through quantitative reconstruction of lake water-balance changes over the past 5000 years

2021 ◽  
Author(s):  
Tim van der Schriek ◽  
Christos Giannakopoulos
Keyword(s):  
Climate Change ◽  
Lake Water ◽  
Water Loss ◽  
Water Surface ◽  
Lake Level ◽  
Open Water ◽  
Water Levels ◽  
The Past ◽  
Lake Water Balance

<p>Ancient lakes throughout the Mediterranean are at risk of disappearing due to a combination of climate change and human impacts. The growing imbalance between water availability and demand is creating unprecedented ecological problems. There is an urgent need for better understanding the patterns of natural lake water variability to improve water resource management and conservation. The incorporation of long-term cycles is particularly important for assessing low frequency – high magnitude trends in lake water levels.</p><p>The Ohrid-Prespa Lake system is amongst the oldest permanent lake systems in Europe, with an age of >1 million years, and hosts a globally significant biodiversity. The closed-basin Prespa Lakes are particularly sensitive to climatic variability with long-term water level changes informing on the dynamic balance between [1] runoff and precipitation supplying water to the lakes, and [2] water loss from the lakes by evaporation and underground karst outflow.</p><p>The large, ongoing, fall of the Prespa Lakes that started in 1987 threatens the biodiversity and water resources of the interconnected lake system. This decline is caused by climate change, specifically by decreases of 10% in precipitation and 25% in runoff, amplified by water abstraction. There is no precedent for this water level fall in the observational record (1951-present), although geological archives indicate equally low water levels at least twice over the past five millennia. </p><p>Here we present the first quantified estimates of changes in the lake water balance over time that are based on the strong relationship between open water surface area and water loss. This quantification allows direct comparison of lake low- and highstand events across time and assessing magnitudes of regional hydro-climatic changes. This study uses a novel approach that reconstructs absolute lake levels and related open water surface areas for different past periods, using the landform-sediment record.</p><p>The hydro-climate of the Prespa catchment shows a drying trend of since the mid Holocene. The recent (2001-2018) lake lowstand is the most significant over the past 700 years in terms of water loss changes. A lake lowstand period of a similar magnitude occurred about 2000 years ago. The most extreme lowstand period over the past 5000 years occurred between 1100-800 years ago during the Medieval Climate Anomaly, when water loss changes were >50% higher compared to the present lowstand. However, the renewed decline in lake level and surface area since 2019 requires close monitoring; if lake level falls a further 2m to 840m.a.s.l. it would become the largest recorded fall over the entire Holocene, with unknown impacts for the wider system.</p><p> </p>

Long-Term Increase in Dissolved Organic Carbon in Streamwaters in Norway Is Response to Reduced Acid Deposition

2007 ◽  
Vol 41 (22) ◽  
pp. 7706-7713 ◽  
Author(s):  
Heleen A. de Wit ◽  
Jan Mulder ◽  
Atle Hindar ◽  
Lars Hole
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Acid Deposition
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