Carbon flux response and recovery to drought years in a hemi-boreal peat bog between different vegetation types

2020 ◽  
Author(s):  
Chris R Taylor ◽  
Ben Keane ◽  
Iain Hartley ◽  
Gareth Phoenix
Keyword(s):  
Carbon Dioxide ◽  
Nutrient Availability ◽  
Anthropogenic Activities ◽  
Terrestrial Ecosystems ◽  
Phosphorus Limitation ◽  
Atmospheric Concentration ◽  
Ecosystem Responses ◽  
N Limitation ◽  
Plant Soil ◽  
P Limitation

<p>Terrestrial ecosystems absorb 30% of anthropogenic carbon dioxide (CO<sub>2</sub>) emissions, slowing its rising atmospheric concentration and substantially inhibiting climate change. This uptake is believed to be due to elevated CO<sub>2</sub> (eCO<sub>2</sub>) stimulating plant photosynthesis and growth, thus increasing carbon (C) storage in plants and soil organic matter. However, nitrogen (N) limitation can reduce ecosystem C uptake capacity under eCO<sub>2</sub> by as much as 50%. Phosphorus (P) limitation in ecosystems is almost as common as N-limitation and is increasing due to ongoing deposition of N from anthropogenic activities. Despite this, we do not know how P-limited ecosystems will respond to eCO<sub>2</sub>, constituting a major gap in our understanding of how large areas of the biosphere will impact atmospheric CO<sub>2</sub> over the coming decades.</p><p>In the first study conducted into the effect of eCO<sub>2</sub> on P-limited ecosystems with manipulated nutrient availability, the Phosphorus Limitation And ecosystem responses to Carbon dioxide Enrichment project (PLACE), investigates the effects of eCO<sub>2</sub> on C cycling in grasslands, which are a critical global C store. Turf mesocosms from P-limited acidic and limestone grasslands, where N and P inputs have been manipulated for 20 years (control, low N (3.5 g m<sup>-2</sup> y<sup>-1</sup>), high N (14 g m<sup>-2</sup> y<sup>-1</sup>), and P (3.5 g m<sup>-2</sup> y<sup>-1</sup>)), have been exposed to either ambient or eCO<sub>2</sub> (600 ppm) in a miniFACE (mini Free Air Carbon Enrichment) system. Long-term P addition has alleviated P limitation while N additions have exacerbated it. The two contrasting grasslands contain different amounts of organic versus mineral P in their soils and, thus, plants may have to use contrasting strategies to acquire the additional P they need to increase growth rates under elevated CO<sub>2</sub>.</p><p>We present data from the first two growing seasons, including above and below ground productivity, and C, N and P cycling through plant, soil and microbial pools. Aboveground harvest data from the second year have shown eCO<sub>2</sub> has only increased biomass production in the limestone grassland (by 17%; p< 0.0001), and not in the acid grassland. There was also a significant effect of nutrient treatment (p< 0.001) with biomass increasing under P and HN, indicating some co-NP limitation. Stable isotope tracing, using the fumigation CO<sub>2</sub> signal has shown the fate of newly assimilated C and its contribution to gaseous C flux to the atmosphere in the form of methane (CH<sub>4</sub>) and respired CO<sub>2</sub>.  In summary, our first two years of eCO<sub>2</sub> treatment suggests that productivity of limestone and acidic grassland respond differently and that these responses depend on nutrient availability, indicating the complexity of predicting P-limited ecosystem responses as atmospheric CO<sub>2 </sub>continues to rise.</p>

Soil Ecology

Ecology ◽  
2012 ◽  
Author(s):  
Franciska T. De Vries ◽  
Richard D. Bardgett
Keyword(s):  
Global Change ◽  
New Technologies ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Soil Ecology ◽  
Biological Interactions ◽  
Soil Biodiversity ◽  
Ecosystem Responses ◽  
Plant Soil

The study of soil ecology has a long tradition. Most of this interest, until relatively recently, has been from an agricultural perspective, but now it is widely accepted that soil ecology is central to the study of terrestrial ecology. Early research in soil ecology was largely descriptive, detailing the abundance of diversity of organisms in soils of different habitats. However, interest in functional soil ecology started in the 1980s with studies of trophic interactions in soil and their importance for nutrient cycles and decomposition. Now, the topic has blossomed, with the help of new technologies that allow the study of soil organisms and their activities in situ, and there is currently widespread recognition that soil ecology is fundamental to our understanding of the functioning of terrestrial ecosystems and their response to global change. Today, the field of soil ecology is dominated by discussions on the use of new molecular tools that enable ecologists to understand what regulates patterns of diversity in soil, the functional role of soil biodiversity and plant-soil interactions, especially those that occur at the root-soil interface, and the role of soil biological communities in regulating ecosystem responses to global change, including the global carbon cycle under climate change. Many challenges still remain in soil ecology, and perhaps the most significant is the need for a stronger theoretical basis for the subject; almost all studies in this area have been carried out from an empirical perspective, and modeling approaches are still in their infancy. As a consequence, our ability to make predictions about the role of soil biological interactions and feedbacks in regulating terrestrial ecosystem processes and their response to global change remains limited.

scholarly journals Exploring the distance between nitrogen and phosphorus limitation in mesotrophic surface waters using a sensitive bioassay

2017 ◽  
Vol 14 (2) ◽  
pp. 379-387 ◽  
Author(s):  
Enis Hrustić ◽  
Risto Lignell ◽  
Ulf Riebesell ◽  
Tron Frede Thingstad
Keyword(s):  
Baltic Sea ◽  
Incubation Time ◽  
Phosphorus Limitation ◽  
Early Summer ◽  
Parameter Estimates ◽  
Nitrogen And Phosphorus ◽  
Field Station ◽  
N Limitation ◽  
P Limitation ◽  
Two Samples

Abstract. The balance in microbial net consumption of nitrogen and phosphorus was investigated in samples collected in two mesotrophic coastal environments: the Baltic Sea (Tvärminne field station) and the North Sea (Espegrend field station). For this, we have refined a bioassay based on the response in alkaline phosphatase activity (APA) over a matrix of combinations in nitrogen and phosphorus additions. This assay not only provides information on which element (N or P) is the primary limiting nutrient, but also gives a quantitative estimate for the excess of the secondary limiting element (P+ or N+, respectively), as well as the ratio of balanced net consumption of added N and P over short timescales (days). As expected for a Baltic Sea late spring–early summer situation, the Tvärminne assays (n =  5) indicated N limitation with an average P+ =  0.30 ± 0.10 µM-P, when incubated for 4 days. For short incubations (1–2 days), the Espegrend assays indicated P limitation, but the shape of the response surface changed with incubation time, resulting in a drift in parameter estimates toward N limitation. Extrapolating back to zero incubation time gave P limitation with N+ ≈  0.9 µM-N. The N : P ratio (molar) of nutrient net consumption varied considerably between investigated locations: from 2.3 ± 0.4 in the Tvärminne samples to 13 ± 5 and 32 ± 3 in two samples from Espegrend. Our assays included samples from mesocosm acidification experiments, but statistically significant effects of ocean acidification were not found by this method.

Climate-forced changes of bio-productivity of Belorussian terrestrial ecosystems

2019 ◽  
pp. 77-88
Author(s):  
S. A. Lysenko
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Vegetation Index ◽  
Precipitation Amount ◽  
Terrestrial Ecosystems ◽  
Vegetation Period ◽  
Climatic Trend ◽  
Vegetation Growth ◽  
Current Century ◽  
The Impact

The spatial and temporal particularities of Normalized Differential Vegetation Index (NDVI) changes over territory of Belarus in the current century and their relationship with climate change were investigated. The rise of NDVI is observed at approximately 84% of the Belarus area. The statistically significant growth of NDVI has exhibited at nearly 35% of the studied area (t-test at 95% confidence interval), which are mainly forests and undeveloped areas. Croplands vegetation index is largely descending. The main factor of croplands bio-productivity interannual variability is precipitation amount in vegetation period. This factor determines more than 60% of the croplands NDVI dispersion. The long-term changes of NDVI could be explained by combination of two factors: photosynthesis intensifying action of carbon dioxide and vegetation growth suppressing action of air warming with almost unchanged precipitation amount. If the observed climatic trend continues the croplands bio-productivity in many Belarus regions could be decreased at more than 20% in comparison with 2000 year. The impact of climate change on the bio-productivity of undeveloped lands is only slightly noticed on the background of its growth in conditions of rising level of carbon dioxide in the atmosphere.

scholarly journals Greenhouse gases, global warming and glacier ice melt in Nepal

2007 ◽  
Vol 8 ◽  
pp. 1-7
Author(s):  
Krishna B. Karki
Keyword(s):  
Carbon Dioxide ◽  
Nitrous Oxide ◽  
Greenhouse Gases ◽  
Greenhouse Effect ◽  
Anthropogenic Activities ◽  
Mineral Fertilizer ◽  
Water Shortage ◽  
Water Volume ◽  
Greenhouse Gasses ◽  
Glacier Ice

Concentration of greenhouse gases has been found increasing over the past centuries. Carbon dioxide (9-26% greenhouse effect), methane (4-9%), and nitrous oxide (3-6%) are the three principal greenhouse gasses though chloroflourocarbon and halon are also included as greenhouse gasses but are in very small greenhouse effect. These gasses are produced both from natural process and anthropogenic activities .Increase of these greenhouse gasses from nature in the atmosphere is mainly from the decomposition of organic matter, nitrification and denitrification of nitrogen including respiration by the plants. Anthropogenic production of carbon dioxide is from burning of fossil fuel whereas for methane livestock and paddy cultivation. Agricultural activities mainly use of mineral fertilizer is responsible for nitrous oxide emission. Increase of these gasses in atmosphere increases temperature that further accelerates evaporation of moisture from the earth’s surface. Increase in water vapor in the atmosphere will further aggravate temperature rise. This increase in atmospheric temperature has direct effect in the melting of glacier ice in Nepalese Himalaya. Melting of ice and increases water volume in the glacier fed rivers and glacier lakes. Rise in water volume beyond its capacity the glacial lakes bursts releasing millions of cubit meters of water and takes million of lives and properties downstream. If this continues there will be no more ice left in the Himalaya and in the long run all the rivers of Nepal will go dry and country will face serious water shortage for drinking, irrigation and other purposes. The Journal of AGRICULTURE AND ENVIRONMENT Vol. 8, 2007, pp. 1-7

scholarly journals On the potential vegetation feedbacks that enhance phosphorus availability – insights from a process-based model linking geological and ecological timescales

2014 ◽  
Vol 11 (13) ◽  
pp. 3661-3683 ◽  
Author(s):  
C. Buendía ◽  
S. Arens ◽  
T. Hickler ◽  
S. I. Higgins ◽  
P. Porada ◽  
...  
Keyword(s):  
Biomass Production ◽  
Primary Productivity ◽  
Chemical Weathering ◽  
Production Efficiency ◽  
Root Exudation ◽  
Terrestrial Ecosystems ◽  
Global Scale ◽  
P Uptake ◽  
P Availability ◽  
P Limitation

Abstract. In old and heavily weathered soils, the availability of P might be so small that the primary production of plants is limited. However, plants have evolved several mechanisms to actively take up P from the soil or mine it to overcome this limitation. These mechanisms involve the active uptake of P mediated by mycorrhiza, biotic de-occlusion through root clusters, and the biotic enhancement of weathering through root exudation. The objective of this paper is to investigate how and where these processes contribute to alleviate P limitation on primary productivity. To do so, we propose a process-based model accounting for the major processes of the carbon, water, and P cycles including chemical weathering at the global scale. Implementing P limitation on biomass synthesis allows the assessment of the efficiencies of biomass production across different ecosystems. We use simulation experiments to assess the relative importance of the different uptake mechanisms to alleviate P limitation on biomass production. We find that active P uptake is an essential mechanism for sustaining P availability on long timescales, whereas biotic de-occlusion might serve as a buffer on timescales shorter than 10 000 yr. Although active P uptake is essential for reducing P losses by leaching, humid lowland soils reach P limitation after around 100 000 yr of soil evolution. Given the generalized modelling framework, our model results compare reasonably with observed or independently estimated patterns and ranges of P concentrations in soils and vegetation. Furthermore, our simulations suggest that P limitation might be an important driver of biomass production efficiency (the fraction of the gross primary productivity used for biomass growth), and that vegetation on old soils has a smaller biomass production rate when P becomes limiting. With this study, we provide a theoretical basis for investigating the responses of terrestrial ecosystems to P availability linking geological and ecological timescales under different environmental settings.

scholarly journals Responses of pea (Pisum sativum L.) to the rising atmospheric concentration of carbon-dioxide

2017 ◽  
pp. 185-188
Author(s):  
András Tamás ◽  
Ágnes Törő ◽  
Tamás Rátonyi ◽  
Endre Harsányi
Keyword(s):  
Carbon Dioxide ◽  
Environmental Factors ◽  
Atmospheric Carbon Dioxide ◽  
Photosynthetic Apparatus ◽  
Carbon Dioxide Concentration ◽  
Growing Season ◽  
Atmospheric Concentration ◽  
Pisum Sativum L ◽  
Key Factor ◽  
Carbon Dioxide Levels

The atmospheric concentration of carbon dioxide increases from decade to decade in increasing pace. In 1957, atmospheric carbon dioxide levels were around 315 ppm, while in 2012 it amounted to 394.49 ppm concentration. In parallel, the global temperature is rising,which is projected to average 1.5–4.5 °C. The carbon dioxide concentration is a key factor – in interaction with the light – affects the plant's photosynthesis. Among the various factors significant interactions prevail: environmental factors affect - the growth and the development of plants, leaf area size and composition, the function of the photosynthetic apparatus, the duration of growing season.

scholarly journals Comparative Analysis of Atmospheric Carbon Dioxide Concentration and Temperature between Forest and Non-Forested Domains in Oyo State, Nigeria

2021 ◽  
Vol 25 (3) ◽  
pp. 445-449
Author(s):  
B.M. Awosusi ◽  
I.S. Adamu ◽  
A.R. Orunkoyi ◽  
D.O. Atiba ◽  
A.A. Obe ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Anthropogenic Activities ◽  
Carbon Dioxide Concentration ◽  
High Rate ◽  
Afternoon Session ◽  
Forest Reserve ◽  
Positive Correlation ◽  
Routine Monitoring ◽  
Reduce Carbon Dioxide

This study was carried out to assess the concentration levels of CO2 and temperature and also to correlate their values among selected locations in Oyo State, Nigeria. CO2 and temperature readings were taken using a portable CO2 meter, and a GPS was use to capture co-ordinates of sample points, this was done twice a day. Data were collected from 7am to 11am for morning session while afternoon session data were collected between 1pm and  5pm making a total of 8 hours monitoring. There were negative correlation between CO2 and temperature in all the forests while we have positive correlation between CO2 and temperature in non-forested domains, this,  by implication, means that presence of trees in the forest reserve help to reduce Carbon dioxide during the day since trees  manufacture their food using CO2 in the presence of sunlight. Also, the positive correlation between CO2 and temperature in the towns is due to high rate of human anthropogenic activities during the day. The values of CO2 obtained in this study were higher when  compared with IPCC limit of 435 ppm (parts per million) of CO2 emission. Routine monitoring of carbon dioxide and public education is recommended. Keywords: Carbon dioxide, Temperature, Forest, Non-Forest, Forest Reserve

scholarly journals Biomass and Carbon Stock Estimation of Udawattakele Forest Reserve in Kandy District of Sri Lanka

2019 ◽  
Vol 8 (2) ◽  
Author(s):  
A.M.S.K. Abeysekara ◽  
S.K. Yatigammana ◽  
K.T. Premakantha
Keyword(s):  
Carbon Dioxide ◽  
Sri Lanka ◽  
Carbon Stock ◽  
Anthropogenic Activities ◽  
Terrestrial Ecosystem ◽  
Total Carbon ◽  
Total Biomass ◽  
Moderate Amount ◽  
Forest Reserve ◽  
Rate Of Increase

Carbon dioxide has gained lot of attention in recent past as a greenhouse gas, and therefore it has a potential to affect the climate pattern of the world. Several anthropogenic activities are known to be responsible for the increased level of carbon in the atmosphere and disruption of the global carbon cycle. However, nature has its own mechanism of sequestering and storing the carbon in its “reservoirs”. Forest has the ability to sequester carbon in their biomass and reduce the rate of increase of atmospheric carbon dioxide. The carbon sequestered in the forest trees are mostly referred to as the biomass of a tree or a forest. It has been identified five carbon pools of the terrestrial ecosystem, involving biomass. The study was designed to estimate biomass stock and then the carbon stock of the Udawattakele Forest Reserve (7°17'58 "N, 80°38'20’’E) in Kandy, Sri Lanka. Allometric equations were used to calculate biomass of trees. The total biomass stock was estimated to be 9475.56 t ha-1 (Mega gram-Mg) and the total carbon stock was estimated to be 4,453.55 t ha-1 (Mg) in the Udawattakele Forest Reserve (UFR). This amount is equivalent to 16,344.52 Mg of carbon dioxide in the atmosphere. UFR holds a moderate amount of biomass/carbon stock and the total carbon density of natural forest and plantations was found to be 36.55 Mg ha-1 and 44.89 Mg ha-1 respectively.

Stochastic analysis of time-series related to ocean acidification

2021 ◽  
Author(s):  
Georgios Vagenas ◽  
Theano Iliopoulou ◽  
Panayiotis Dimitriadis ◽  
Demetris Koutsoyiannis
Keyword(s):  
Carbon Dioxide ◽  
Time Series ◽  
Ocean Acidification ◽  
Atmospheric Carbon Dioxide ◽  
Anthropogenic Activities ◽  
Time Lag ◽  
Carbon Dioxide Concentration ◽  
Carbon Dioxide Partial Pressure ◽  
Chemical Transformations ◽  
Mauna Loa

<p>Since the pre-industrial era at the end of the 18<sup>th</sup> century, the atmospheric carbon dioxide concentration (CO<sub>2</sub>) has increased by 47.46% from the level of 280 ppmv (parts per million volume) to 412.89 ppmv (Mauna Loa – NOAA Station, November 2020). These increased concentrations caused by natural & anthropogenic activities, interact with the aquatic environment which acts as a safety valve. Nevertheless, the absorbed CO<sub>2 </sub>amounts undergo chemical transformations, resulting in increasing ionized concentrations that can significantly reduce the water’s pH, a process described as ocean acidification. Here, we use the HOT (Hawaii-Ocean-Time series) to perform time series analysis for temperature, carbon dioxide partial pressure and pH. More specifically, we analyze their temporal changes in month and annual time lag. Then, we proceed in comparisons with relevant studies on atmospheric data to evaluate the produced results. Finally, we make an effort to disentangle the results with simplified assumptions connected with the observed impact of ocean acidification on the aquatic ecosystems.</p>

Climate Change as a Threat to Brazil’s Amazon Forest

2013 ◽  
Vol 4 (3) ◽  
pp. 1-12 ◽  
Author(s):  
Philip M. Fearnside
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Forest Fires ◽  
Climate Changes ◽  
Woody Vegetation ◽  
Amazon Forest ◽  
Atmospheric Concentration ◽  
Current Century ◽  
Climate Convention ◽  
Definition Of

Climate changes predicted for Brazilian Amazonia place much of the forest in danger of dieoff from the combined effect of drought and heat within the current century, and much sooner for some areas. Increases are expected in the frequency and magnitude of droughts from both the El Niño phenomenon and from the Atlantic dipole. These changes imply increased frequency of forest fires. Forest death from drought, fires or both would be followed by a transformation either to a savanna or to some type of low-biomass woody vegetation, in either case with greatly reduced biodiversity. This risk provides justification for Brazil to change its negotiating positions under the Climate Convention to accept a binding target now for national emissions and to support a low atmospheric concentration of carbon dioxide (400 ppmv or less) as the definition of “dangerous” interference with the climate system.

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