biomass loss
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2022 ◽  
Vol 8 ◽  
Author(s):  
Francisco J. L. Gordillo ◽  
Raquel Carmona ◽  
Carlos Jiménez

Continuous winter darkness at a latitude of 79°N was simulated in cultures of four species of Arctic seaweeds at 3 and 8°C. The laminarians Saccharina latissima and Alaria esculenta, and the rhodophytes Phycodrys rubens and Ptilota gunneri were monitored for 4 months in total darkness and after 1 week following light return in early spring, under controlled laboratory conditions. Biomass loss during darkness was enhanced by the high temperature in all species. At 8°C, the two laminarians were unable to resume growth upon re-illumination. Alaria esculenta showed new blade production by the end of the dark period, but only at 3°C. In all species, the photosynthetic ability was sustained, not suspended, during the whole dark period. P. rubens exhibited lower photosynthetic potential at 8°C than at 3°C during the darkness period, but it was able to recover its O2 evolving potential upon re-illumination, as P. gunneri and S. latissima did, but the latter only at 3°C. The reactivation of photosynthesis seemed to involve photosystem II over photosystem I, as 7 d of photoperiod after the prolonged darkness was not enough to fully recover the PAM-related photosynthetic parameters. Only small changes were recorded in the internal chemical composition (total C, total N, carbohydrates, proteins, and lipids), but species-specific differences were observed. Unlike subarctic areas with an operating photoperiod along the year, a warmer polar night might pose a limit to the ability of multi-year seaweeds to occupy the new ice-free illuminated areas of the Arctic coasts, so that newcomers will potentially be restricted to the spring-summer season.


Author(s):  
Emma Ladouceur ◽  
Shane Blowes ◽  
Jonathan Chase ◽  
Adam Clark ◽  
Magda Garbowski ◽  
...  

Global change drivers such as anthropogenic nutrient inputs simultaneously alter biodiversity, species composition, and ecosystem functions such as above ground biomass. These changes are interconnected by complex feedbacks among extinction, invasion, and shifting relative abundance. Here, we use a novel temporal application of the Price equation to separate species richness and biomass change through time and quantify the functional contributions of species that are lost, gained, and persist under ambient and experimental nutrient addition in 59 global grasslands. Under ambient conditions, compositional and biomass turnover was high, but species losses (i.e., local extinctions) were balanced by gains (i.e. colonization). Under fertilization, there was biomass loss associated with species loss. Few species were gained in fertilized conditions over time but those that were, and species that persisted, contributed to net biomass gains, outweighing biomass loss. These components of community change are associated with distinct effects on measures of ecosystem functioning.


2022 ◽  
Author(s):  
Lauren M Tom ◽  
Martina Aulitto ◽  
Yu-Wei Wu ◽  
Yu W Gao ◽  
Kai Deng ◽  
...  

Plant cell walls are interwoven structures recalcitrant to degradation. Both native and adapted microbiomes are particularly effective at plant cell wall deconstruction. Studying these deconstructive microbiomes provides an opportunity to assess microbiome performance and relate it to specific microbial populations and enzymes. To establish a system assessing comparative microbiome performance, parallel microbiomes were cultivated on sorghum (Sorghum bicolor L. Moench) from compost inocula. Biomass loss and biochemical assays indicated that these microbiomes diverged in their ability to deconstruct biomass. Network reconstructions from time-dependent gene expression identified key deconstructive groups within the adapted sorghum-degrading communities, including Actinotalea, Filomicrobium, and Gemmanimonadetes populations. Functional analysis of gene expression demonstrated that the microbiomes proceeded through successional stages that are linked to enzymes that deconstruct plant cell wall polymers. This combination of network and functional analysis highlighted the importance of cellulose-active Actinobacteria in differentiating the performance of these microbiomes.


2021 ◽  
Vol 64 (11) ◽  
pp. 839-845
Author(s):  
V. P. Meshalkin ◽  
O. B. Butusov ◽  
V. G. Dovi ◽  
A. Yu. Belozerskii ◽  
V. V. Chelnokov

The considered operating ferrous metallurgy enterprise uses three different technological modes of steel smelting, each of which is characterized by an individual composition of the ingredients of chemical pollutant emissions into the atmosphere affecting the state of the forest areas around this enterprise. Based on the decoding of satellite pixel photographs of forest areas, the technological mode with the least impact on forest areas was determined. It corresponds to the condition of the minimum area of ecological zones around the ferrous metallurgy enterprise. The authors propose an assessment of the impact of chemical pollution of ferrous metallurgy enterprises on forests in the form of areas of ecological zones of the state of forest vegetation and the volume of biomass in its various parts. The mosaic of ecological zones of forest areas is determined from their satellite pixel photographs using an original algorithm of “controlled cluster analysis”. The main recommendation for ferrous metallurgy enterprises to choose one of several alternative technological modes is as follows: the choice of technological mode should be based on a comparison of sizes of the areas of ecological zones. In this case, the technological mode with the smallest dimensions of the area is selected. Assessment of the damage caused by the chemical pollution of the plant to forest areas was determined by the area of ecological zones and the volume of biomass loss in forest areas in comparison with the background areas. The boundaries of ecological zones can be determined according to the “dose-effect” dependencies typical for the considered region.


2021 ◽  
Vol 10 (6) ◽  
pp. 3178-3190
Author(s):  
Ahmad Yahya Dawod ◽  
Mohammed Ali Sharafuddin

Mangrove is one of the most productive global forest ecosystems and unique in linking terrestrial and marine environment. This study aims to clarify and understand artificial intelligence (AI) adoption in remote sensing mangrove forests. The performance of machine learning algorithms such as random forest (RF), support vector machine (SVM), decision tree (DT), and object-based nearest neighbors (NN) algorithms were used in this study to automatically classify mangrove forests using orthophotography and applying an object-based approach to examine three features (tree cover loss, above-ground carbon dioxide (CO2) emissions, and above-ground biomass loss). SVM with a radial basis function was used to classify the remainder of the images, resulting in an overall accuracy of 96.83%. Precision and recall reached 93.33 and 96%, respectively. RF performed better than other algorithms where there is no orthophotography. 


2021 ◽  
Author(s):  
Stefanie Falk ◽  
Ane V. Vollsnes ◽  
Aud B. Eriksen ◽  
Lisa Emberson ◽  
Connie O'Neill ◽  
...  

Abstract. The unique vegetation of the subarctic region acclimatized to extremes of cold and midnight sun are likely to be at threat from the combined impacts of climate change and increasing ozone concentrations [O3]. The atmospheric and climatic characteristics of the subarctic are known to lead to pronounced peak [O3] in spring. To date, only a few studies assessed the response of subarctic vegetation to variations in climate and air pollution. This study looks to fill this knowledge gap by examining essential climate variables, in particular ozone, over the past few decades. We evaluate the extent to which two recent years (2018 and 2019) deviate from climatic and [O3] norms and how these potentially more frequent future deviations may influence ozone damage to subarctic vegetation. We find that 2018 was an anomalously warm and bright year, particularly in spring and early summer. Higher than average [O3] was observed in April/May while frequent episodes of ozone volume mixing ratios (VMRs) above 40 ppb occurred in June–August. These episodes are in part attributable to forest fires in the Northern Hemisphere and warmer and sunnier conditions. We apply the integrated flux-metric Phytotoxic Ozone Dose (POD) to determine ozone risk and damage to vegetation as a function of [O3], environmental factors, and species-specific physiology. Our study suggests that using generic parameterizations in assessments likely leads to underestimating the risk of ozone damage in this region. We find that bespoke parameterizations of plant functional types (PFTs) for subarctic vegetation bio-types result in an ozone-induced biomass loss of 2.5 to 17.4 %. For some species, this loss is up to 6 % larger than projected from generic parameterizations. Efforts should be targeted towards accurately defining subarctic vegetations' physiological response to essential climate variables. Our method could help to improve regional and global scale biogeochemical cycling under current and future climates.


2021 ◽  
Author(s):  
Nor Syazwani Zainal Abidin ◽  
Khairul Azlan Mustapha ◽  
Wan Hasiah Abdullah ◽  
Zainey Konjing

Abstract The eight coal seams of Neogene paralic coals from Mukah coalfield, Sarawak, Malaysia, were investigated using petrographical, palynological, and organic geochemical analyses to describe coal-forming vegetation, conditions during peat development and precursor mires, and their associations in a sequence-stratigraphic context. The petrographic data of the coals implies the existence of oxygen-deficient and water-saturated conditions in the precursor mires. The condition of low mire oxidation was followed by biomass loss from the mires. The Mukah coals are suggested to be deposited in freshwater peat swamps, and the rich preservation of angiosperm pollens indicates that the organic matter in dense and lowland forest vegetation was mostly terrigenous. The overwhelming presence of Casuarina and Calamus types, suggesting the paleomires were closely linked to Kerapah/Kerangas peat forest and marginally bordered by rattan and supported by the biomarker data. Rheotrophic–ombrotrophic mires were temporarily formed because of water table fluctuations, which strongly depend on ever-wet climate changes and syn-depositional tectonic during the Neogene, resulting in balanced to high peat accumulation and preservation. A maximum thickness of 35m of peat deposits that formed between 10,000 and 175,000 years ago is suggested. The coals are proposed to be influenced by transgressive to initial highstand cycles within the paralic setting.


Fire ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 64
Author(s):  
Liubov Volkova ◽  
Wahyu Catur Adinugroho ◽  
Haruni Krisnawati ◽  
Rinaldi Imanuddin ◽  
Christopher John Weston

Although accurate estimates of biomass loss during peat fires, and recovery over time, are critical in understanding net peat ecosystem carbon balance, empirical data to inform carbon models are scarce. During the 2019 dry season, fires burned through 133,631 ha of degraded peatlands of Central Kalimantan. This study reports carbon loss from surface fuels and the top peat layer of 18.5 Mg C ha−1 (3.5 from surface fuels and 15.0 from root/peat layer), releasing an average of 2.5 Gg (range 1.8–3.1 Gg) carbon in these fires. Peat surface change measurements over one month, as the fires continued to smolder, indicated that about 20 cm of the surface was lost to combustion of peat and fern rhizomes, roots and recently incorporated organic residues that we sampled as the top peat layer. Time series analysis of live green vegetation (NDVI trend), combined with field observations of vegetation recovery two years after the fires, indicated that vegetation recovery equivalent to fire-released carbon is likely to occur around 3 years after fires.


2021 ◽  
Author(s):  
Ulrike Hiltner ◽  
Andreas Huth ◽  
Rico Fischer

Abstract. Disturbances, such as extreme weather events, fires, floods, and biotic agents, can have strong impacts on the dynamics and structures of tropical forests. In the future, the intensity of disturbances will likely further increase, which may have more serious consequences for tropical forests than those we have already observed. Thus, quantifying aboveground biomass loss of forest stands due to tree mortality (hereafter biomass loss) is important for the estimation of the role of tropical forests in the global carbon cycle. So far, the long-term impacts of altered tree mortality on rates of biomass loss have been described little. This study aims to analyse the consequences of long-term elevated tree mortality rates on forest dynamics and biomass loss. We applied an individual-based forest model and investigated the impacts of permanently increased tree mortality rates on the growth dynamics of humid, terra firme forests in French Guiana. Here, we focused on biomass, leaf area index (LAI), forest height, productivity, forest age, quadratic mean stem diameter, and biomass loss. Based on the simulations, we developed a multiple linear regression model to estimate biomass losses of forests in different successional states from the various forest attributes. The findings of our simulation study indicated that increased tree mortality altered the succession patterns of forests in favour of fast-growing species, which changed the forests’ gross primary production, though net primary production remained stable. Tree mortality intensity had a strong influence on the functional species composition and tree size distribution, which led to lower values in LAI, biomass, and forest height at the ecosystem level. We observed a strong influence of a change in tree mortality on biomass loss. Assuming a doubling of tree mortality, biomass loss increased (from 3.2 % y−1 to 4.5 % y−1). We also obtained a multidimensional relationship that allowed for the estimation of biomass loss from forest height and LAI. Via an example, we applied this relationship to remote sensing data of LAI and forest height and mapped biomass loss for French Guiana. We estimated a mean biomass loss rate of 3.2 % per year. The approach described here provides a novel methodology for quantifying biomass loss, taking the successional state of tropical forests into account. Quantifying biomass loss rates may help to reduce uncertainties in the analysis of the global carbon cycle.


2021 ◽  
Author(s):  
Ling Fei ◽  
ShaoFan Zuo ◽  
JiaXin Zhang ◽  
ZhaoLong Wang

Abstract Phytoextraction strategy by harvesting dead leaves provides non-stop phytoremediation and a great saving in disposal cost of hazardous plant residues. This strategy is entirely dependent upon the amount of cadmium (Cd) accumulated in dead leaves. However, it is unknown that whether the leaf Cd accumulation is associated with its senescence and how to regulate its Cd accumulation. This study showed that Cd was preferentially and consistently distributed to and accumulated in the senescent leaves with the new leaf emergence and the old leaf dieback under 75 µM of Cd stress in tall fescue (Festuca arundinacea). Individual leaf monitoring from its emergence to senescence showed that Cd concentration increased exponentially with the leaf life cycle, while leaf biomass decreased gradually after 14 d of leaf emergence. The total amount of Cd accumulated in the leaf showed an exponential increase during leaf senescence, regardless of the leaf biomass loss. Our results demonstrated that leaf Cd accumulation was significantly associated with its senescence and the highest Cd accumulated in dead leaves could be contributed from the continuous Cd input during the leaf senescent process, indicating that further regulatory studies should be focused on the leaf senescence process to achieve higher Cd accumulation and phytoextraction efficiency by harvesting dead leaves.


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