Structure and function of biological soil crusts from Antarctica with a special respect to their microtopography and UV-B sensitivity

2019 ◽  
Vol 9 (2) ◽  
pp. 243-250
Author(s):  
Kateřina Trnková ◽  
Nele Tschense
Keyword(s):  
Biological Soil Crusts ◽  
Quantum Yields ◽  
Professional Literature ◽  
Fine Grained ◽  
Soil Crusts ◽  
Acclimatory Response ◽  
James Ross Island ◽  
Special Respect ◽  
And Function

Although an extensive professional literature exists on biological soil crusts (BSCs), especially on the species composition of hetero- and autotrophs forming the micro-biological comunity, micromorphological information on BSCs is extremely scarce. In our study, we focused on microstructure of the BSCs from the James Ross Island (Antarctica). We combined the approach of digital microscopy to study surface roughness of the BSCs with taxonomy of BSC-forming autotrophs and chlorophyll fluorescence study focused on the photosynthetic functioning of BSCs when exposed to controlled UV-B stress. Microprofiling of BSCs resulted in the finding that the examined BSCs might be classified as fine-grained surface with roughness characteristics: Ra (37.9 μm) and Rz (136.9 μm). The BSCs were rich in microautotrophs, both algae and cyanobacteria, however, Microcoleus sp. was found dominating species. It formed multifilament ropes on and inside the BSCs. Under UV-B stress, Microcoleus- and Nostoc-dominated BSC parts showed similar sensitivity and acclimatory response so long-term UV-B treatment, however, Microcoleus seemed to be slightly more sensitive to UV-B. Microcoleus-dominated parts of BSCs showed less pronounced acclimation to UV-B treatment than Nostoc-dominated parts. It was reflected in lower values of maximum (FV/FM) and effective (FPSII) quantum yields recorded after 6 d exposition.

scholarly journals Climate change and physical disturbance cause similar community shifts in biological soil crusts

2015 ◽  
Vol 112 (39) ◽  
pp. 12116-12121 ◽  
Author(s):  
Scott Ferrenberg ◽  
Sasha C. Reed ◽  
Jayne Belnap
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Summer Rainfall ◽  
Community Change ◽  
Biological Soil Crusts ◽  
Physical Disturbance ◽  
Precipitation Frequency ◽  
Soil Crusts ◽  
Altered Precipitation

Biological soil crusts (biocrusts)—communities of mosses, lichens, cyanobacteria, and heterotrophs living at the soil surface—are fundamental components of drylands worldwide, and destruction of biocrusts dramatically alters biogeochemical processes, hydrology, surface energy balance, and vegetation cover. Although there has been long-standing concern over impacts of physical disturbances on biocrusts (e.g., trampling by livestock, damage from vehicles), there is increasing concern over the potential for climate change to alter biocrust community structure. Using long-term data from the Colorado Plateau, we examined the effects of 10 y of experimental warming and altered precipitation (in full-factorial design) on biocrust communities and compared the effects of altered climate with those of long-term physical disturbance (>10 y of replicated human trampling). Surprisingly, altered climate and physical disturbance treatments had similar effects on biocrust community structure. Warming, altered precipitation frequency [an increase of small (1.2 mm) summer rainfall events], and physical disturbance from trampling all promoted early successional community states marked by dramatic declines in moss cover and increases in cyanobacteria cover, with more variable effects on lichens. Although the pace of community change varied significantly among treatments, our results suggest that multiple aspects of climate change will affect biocrusts to the same degree as physical disturbance. This is particularly disconcerting in the context of warming, as temperatures for drylands are projected to increase beyond those imposed as treatments in our study.

scholarly journals Water and Heat-Triggered Changes of Bacterial Community Structure and Function in Biological Soil Crusts

2021 ◽  
Author(s):  
Xiaoting Wei ◽  
Fuwen Qin ◽  
Bing Han ◽  
Huakun Zhou ◽  
Miao Liu ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Aridity Index ◽  
Soil Improvement ◽  
Biological Soil Crusts ◽  
Structure And Function ◽  
Soil Crusts ◽  
And Function

Abstract Background and Aims：The outstanding ability of biological soil crusts (BSCs) in soil microenvironments regulation is mainly attribute to microorganisms that colonizing in biocrusts. We aimed to investigate the changes of bacterial community structure and function with biocrust succession, as well as their responses to climatic changes across large geographical scales.Methods: Algal BSCs and lichen BSCs were sampled along an aridity gradient on alpine grasslands. Bacterial communities in biocrusts were measured using high-throughput sequencing, and soil underlying biocrusts (0-5 cm) was collected for nutrients determination. Results: Our results indicated that compared with algal BSCs, bacterial community in lichen BSCs was characterized by lower diversity, more complex co-occurrence network and mutually beneficial relationships. The bacterial community assembly was governed mainly by stochastic processes for lichen BSCs, which was different from the almost equally important roles of stochastic and deterministic processes for algal BSCs. Geographical location had a significant effect on bacterial communities in both algal and lichen BSCs, while had a greater effect on lichen BSCs. It is noteworthy that the bacterial diversity of algal BSCs was positively correlated with aridity index, while that of lichens was negatively correlated with aridity index. Moreover, we determined lower soil pH and higher soil phosphorus content underlying lichen BSCs, implying their advantages in soil improvement. Conclusions: Aridity index was one of important driving factors of bacterial community in biocrusts, and its effects were biocrust type dependent. Lichen BSCs had greater effects on soil improvement than that of algal BSCs.

Effects of inoculated Microcoleus vaginatus on the structure and function of biological soil crusts of desert

2010 ◽  
Vol 47 (4) ◽  
pp. 473-480 ◽  
Author(s):  
Yunpu Zheng ◽  
Ming Xu ◽  
Jiancheng Zhao ◽  
Shuqing Bei ◽  
Lihua Hao
Keyword(s):  
Biological Soil Crusts ◽  
Structure And Function ◽  
Soil Crusts ◽  
Microcoleus Vaginatus ◽  
And Function

Discussion on wind factor influencing the distribution of biological soil crusts on surface of sand dunes

2013 ◽  
Vol 5 (6) ◽  
pp. 739
Author(s):  
Wu YongSheng ◽  
Erdun Hasi ◽  
Yin RuiPing ◽  
Zhang Xin ◽  
Ren Jie ◽  
...  
Keyword(s):  
Sand Dunes ◽  
Biological Soil Crusts ◽  
Soil Crusts

scholarly journals Domain randomization-enhanced deep learning models for bird detection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xin Mao ◽  
Jun Kang Chow ◽  
Pin Siang Tan ◽  
Kuan-fu Liu ◽  
Jimmy Wu ◽  
...  
Keyword(s):  
Deep Learning ◽  
Continuous Monitoring ◽  
Bird Species ◽  
Training Data ◽  
Learning Models ◽  
Fine Grained ◽  
Bird Detection ◽  
Relationship Of ◽  
The Relationship

AbstractAutomatic bird detection in ornithological analyses is limited by the accuracy of existing models, due to the lack of training data and the difficulties in extracting the fine-grained features required to distinguish bird species. Here we apply the domain randomization strategy to enhance the accuracy of the deep learning models in bird detection. Trained with virtual birds of sufficient variations in different environments, the model tends to focus on the fine-grained features of birds and achieves higher accuracies. Based on the 100 terabytes of 2-month continuous monitoring data of egrets, our results cover the findings using conventional manual observations, e.g., vertical stratification of egrets according to body size, and also open up opportunities of long-term bird surveys requiring intensive monitoring that is impractical using conventional methods, e.g., the weather influences on egrets, and the relationship of the migration schedules between the great egrets and little egrets.

scholarly journals Climate Mobility and Development Cooperation

2021 ◽  
Author(s):  
Robert Stojanov ◽  
Sarah Rosengaertner ◽  
Alex de Sherbinin ◽  
Raphael Nawrotzki
Keyword(s):  
Climate Adaptation ◽  
Human Mobility ◽  
Climate Impacts ◽  
Development Cooperation ◽  
Climate Variability And Change ◽  
Policy Frameworks ◽  
And Migration ◽  
And Function ◽  
Role And Function

AbstractDevelopment cooperation actors have been addressing climate change as a cross-cutting issue and investing in climate adaptation projects since the early 2000s. More recently, as concern has risen about the potential impacts of climate variability and change on human mobility, development cooperation actors have begun to design projects that intentionally address the drivers of migration, including climate impacts on livelihoods. However, to date, we know little about the development cooperation’s role and function in responding to climate related mobility and migration. As such, the main aim of this paper is to outline the policy frameworks and approaches shaping development cooperation actors’ engagement and to identify areas for further exploration and investment. First, we frame the concept of climate mobility and migration and discuss some applicable policy frameworks that govern the issue from various perspectives; secondly, we review the toolbox of approaches that development cooperation actors bring to climate mobility; and third, we discuss the implications of the current Covid-19 pandemic and identify avenues for the way forward. We conclude that ensuring safe and orderly mobility and the decent reception and long-term inclusion of migrants and displaced persons under conditions of more severe climate hazards, and in the context of rising nationalism and xenophobia, poses significant challenges. Integrated approaches across multiple policy sectors and levels of governance are needed. In addition to resources, development cooperation actors can bring data to help empower the most affected communities and regions and leverage their convening power to foster more coordinated approaches within and across countries.

scholarly journals Non-Local and Multi-Scale Mechanisms for Image Inpainting

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3281
Author(s):  
Xu He ◽  
Yong Yin
Keyword(s):  
Markov Random Fields ◽  
Receptive Fields ◽  
Image Inpainting ◽  
Long Distance ◽  
Visual Appearance ◽  
Fine Grained ◽  
Multi Scale ◽  
Non Local ◽  
Relationship Of

Recently, deep learning-based techniques have shown great power in image inpainting especially dealing with squared holes. However, they fail to generate plausible results inside the missing regions for irregular and large holes as there is a lack of understanding between missing regions and existing counterparts. To overcome this limitation, we combine two non-local mechanisms including a contextual attention module (CAM) and an implicit diversified Markov random fields (ID-MRF) loss with a multi-scale architecture which uses several dense fusion blocks (DFB) based on the dense combination of dilated convolution to guide the generative network to restore discontinuous and continuous large masked areas. To prevent color discrepancies and grid-like artifacts, we apply the ID-MRF loss to improve the visual appearance by comparing similarities of long-distance feature patches. To further capture the long-term relationship of different regions in large missing regions, we introduce the CAM. Although CAM has the ability to create plausible results via reconstructing refined features, it depends on initial predicted results. Hence, we employ the DFB to obtain larger and more effective receptive fields, which benefits to predict more precise and fine-grained information for CAM. Extensive experiments on two widely-used datasets demonstrate that our proposed framework significantly outperforms the state-of-the-art approaches both in quantity and quality.

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