scholarly journals Expanding Perspectives of Element Cycling from 1970 to 2020: The Influence of Stumm and Morgan

2021 ◽  
Author(s):  
David A. Dzombak ◽  
Miranda R. Gorman
Keyword(s):  
Element Cycling

scholarly journals Marine Gel Interactions with Hydrophilic and Hydrophobic Pollutants

Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 83
Author(s):  
Peter H. Santschi ◽  
Wei-Chun Chin ◽  
Antonietta Quigg ◽  
Chen Xu ◽  
Manoj Kamalanathan ◽  
...  
Keyword(s):  
Metal Ions ◽  
Food Web ◽  
Microbial Ecology ◽  
Particle Interactions ◽  
Marine Microbes ◽  
Element Cycling ◽  
Exopolymeric Substances ◽  
Hydrophobic Pollutants ◽  
Pollutant Distribution ◽  
Ultimate Fate

Microgels play critical roles in a variety of processes in the ocean, including element cycling, particle interactions, microbial ecology, food web dynamics, air–sea exchange, and pollutant distribution and transport. Exopolymeric substances (EPS) from various marine microbes are one of the major sources for marine microgels. Due to their amphiphilic nature, many types of pollutants, especially hydrophobic ones, have been found to preferentially associate with marine microgels. The interactions between pollutants and microgels can significantly impact the transport, sedimentation, distribution, and the ultimate fate of these pollutants in the ocean. This review on marine gels focuses on the discussion of the interactions between gel-forming EPS and pollutants, such as oil and other hydrophobic pollutants, nanoparticles, and metal ions.

scholarly journals Grasshopper herbivory immediately affects element cycling but not export rates in an N‐limited grassland system

Ecosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Karin Potthast ◽  
Stefanie Meyer ◽  
Alexander Tischer ◽  
Gerd Gleixner ◽  
Anne Sieburg ◽  
...  
Keyword(s):  
Element Cycling

scholarly journals Element Cycling in the Critical Zone as Viewed by New Isotope Tools

2014 ◽  
Vol 10 ◽  
pp. 173-178 ◽  
Author(s):  
Friedhelm von Blanckenburg ◽  
Jan A. Schuessler
Keyword(s):  
Critical Zone ◽  
Element Cycling

scholarly journals High-throughput amplicon sequencing reveals the spatiotemporal effects, abiotic and biotic shaping factors for the microbial communities in tropical mangrove sediments in Sanya, China

2020 ◽  
Author(s):  
Wu Qu ◽  
Boliang Gao ◽  
Jie Wu ◽  
Min Jin ◽  
Jianxin Wang ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Communities ◽  
Fungal Community ◽  
Amplicon Sequencing ◽  
Biotic Factors ◽  
Community Structures ◽  
Mangrove Sediments ◽  
Element Cycling ◽  
Microbial Community Structures

Abstract Background Microbial roles in element cycling and nutrient providing are crucial for mangrove ecosystems and serve as important regulators for climate change in Earth ecosystem. However, some key information about the spatiotemporal influences and abiotic and biotic shaping factors for the microbial communities in mangrove sediments remains lacking. Methods In this work, 22 sediment samples were collected from multiple spatiotemporal dimensions, including three locations, two depths, and four seasons, and the bacterial, archaeal, and fungal community structures in these samples were studied using amplicon sequencing. Results The microbial community structures were varied in the samples from different depths and locations based on the results of LDA effect size analysis, principal coordinate analysis, the analysis of similarities, and permutational multivariate ANOVA. However, these microbial community structures were stable among the seasonal samples. Linear fitting models and Mantel test showed that among the 13 environmental factors measured in this study, the sediment particle size (PS) was the key abiotic shaping factor for the bacterial, archaeal, or fungal community structure. Besides PS, salinity and humidity were also significant impact factors according to the canonical correlation analysis (p ≤ 0.05). Co-occurrence networks demonstrated that the bacteria assigned into phyla Ignavibacteriae, Proteobacteria, Bacteroidetes, Chloroflexi, and Acidobacteria were the key biotic factors for shaping the bacterial community in mangrove sediments. Conclusions This work showed the variability on spatial dimensions and the stability on temporal dimension for the bacterial, archaeal, or fungal microbial community structure, indicating that the tropical mangrove sediments are versatile but stable environments. PS served as the key abiotic factor could indirectly participate in material circulation in mangroves by influencing microbial community structures, along with salinity and humidity. The bacteria as key biotic factors were found with the abilities of photosynthesis, polysaccharide degradation, or nitrogen fixation, which were potential indicators for monitoring mangrove health, as well as crucial participants in the storage of mangrove blue carbons and mitigation of climate warming. This study expanded the knowledge of mangroves for the spatiotemporal variation, distribution, and regulation of the microbial community structures, thus further elucidating the microbial roles in mangrove management and climate regulation.

scholarly journals Geographical and Seasonal Thermal Sensitivity of Grazing Pressure by Microzooplankton in Contrasting Marine Ecosystems

2021 ◽  
Vol 12 ◽  
Author(s):  
Marco J. Cabrerizo ◽  
Emilio Marañón
Keyword(s):  
Thermal Sensitivity ◽  
Grazing Pressure ◽  
Open Ocean ◽  
Effect Of Temperature ◽  
Extensive Literature ◽  
Thermal Dependence ◽  
Food Web Structure ◽  
Element Cycling ◽  
Large Variability ◽  
Microzooplankton Grazing

Grazing pressure, estimated as the ratio between microzooplankton grazing and phytoplankton growth rates (g:μ), is a strong determinant of microbial food-web structure and element cycling in the upper ocean. It is generally accepted that g is more sensitive to temperature than μ, but it remains unknown how the thermal dependence (activation energy, Ea) of g:μ varies over spatial and temporal scales. To tackle this uncertainty, we used an extensive literature analysis obtaining 751 paired rate estimates of μ and g from dilution experiments performed throughout the world’s marine environments. On a geographical scale, we found a stimulatory effect of temperature in polar open-ocean (∼0.5 eV) and tropical coastal (∼0.2 eV) regions, and an inhibitory one in the remaining biomes (values between −0.1 and −0.4 eV). On a seasonal scale, the temperature effect on g:μ ratios was stimulatory, particularly in polar environments; however, the large variability existing between estimates resulted in non-significant differences among biomes. We observed that increases in nitrate availability stimulated the temperature dependence of grazing pressure (i.e., led to more positive Ea of g:μ) in open-ocean ecosystems and inhibited it in coastal ones, particularly in polar environments. The percentage of primary production grazed by microzooplankton (∼56%) was similar in all regions. Our results suggest that warming of surface ocean waters could exert a highly variable impact, in terms of both magnitude and direction (stimulation or inhibition), on microzooplankton grazing pressure in different ocean regions.

Freshwater mussel shells (Unionidae) describe anthropogenic changes to trace element cycling within a North American river

2018 ◽  
Vol 616-617 ◽  
pp. 1066-1076 ◽  
Author(s):  
W. Aaron Wilson ◽  
Andrea K. Fritts ◽  
Mark W. Fritts ◽  
Jason M. Unrine ◽  
Brent N. Tweedy ◽  
...  
Keyword(s):  
Trace Element ◽  
North American ◽  
Freshwater Mussel ◽  
Element Cycling ◽  
Anthropogenic Changes ◽  
American River ◽  
Mussel Shells

Integrated Element Cycling

2017 ◽  
pp. 131-139 ◽  
Author(s):  
Christopher S. Cronan
Keyword(s):  
Element Cycling

scholarly journals A new terrestrial biosphere model with coupled carbon, nitrogen, and phosphorus cycles (QUINCY v1.0; revision 1772)

2019 ◽  
Author(s):  
Tea Thum ◽  
Silvia Caldararu ◽  
Jan Engel ◽  
Melanie Kern ◽  
Marleen Pallandt ◽  
...  
Keyword(s):  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Ecosystem Dynamics ◽  
Soil Conditions ◽  
Monitoring Networks ◽  
Nitrogen And Phosphorus ◽  
Element Cycling ◽  
Terrestrial Biosphere ◽  
Ecosystem Monitoring ◽  
Terrestrial Ecosystem Model

Abstract. The dynamics of terrestrial ecosystems are shaped by the coupled cycles of carbon, nitrogen and phosphorus, and strongly depend on the availability of water and energy. These interactions shape future terrestrial biosphere responses to global change. Many process-based models of the terrestrial biosphere have been gradually extended from considering carbon-water interactions to also including nitrogen, and later, phosphorus dynamics. This evolutionary model development has hindered full integration of these biogeochemical cycles and the feedbacks amongst them. Here we present a new terrestrial ecosystem model QUINCY (QUantifying Interactions between terrestrial Nutrient CYcles and the climate system), which is formulated around a consistent representation of element cycling in terrestrial ecosystems. This new model includes i) a representation of plant growth which separates source (e.g. photosynthesis) and sink (growth rate of individual tissues, constrained by nutrients, temperature, and water availability) processes; ii) the acclimation of many ecophysiological processes to meteorological conditions and/or nutrient availabilities; iii) an explicit representation of vertical soil processes to separate litter and soil organic matter dynamics; iv) a range of new diagnostics (leaf chlorophyll content; 13C, 14C, and 15N isotope tracers) to allow for a more in-depth model evaluation. We present the model structure and provide an assessment of its performance against a range of observations from global-scale ecosystem monitoring networks. We demonstrate that the framework is capable of consistently simulating ecosystem dynamics across a large gradient in climate and soil conditions, as well as across different plant functional types. To aid this understanding we provide an assessment of the model's sensitivity to its parameterisation and the associated uncertainty.

Forest Element Cycling

1986 ◽  
pp. 55-60
Author(s):  
J. O. Reuss ◽  
D. W. Johnson
Keyword(s):  
Element Cycling

An integrated watershed/plot-scale study of element cycling in spruce ecosystems of the black forest

1990 ◽  
Vol 54 (4) ◽  
pp. 545-560 ◽  
Author(s):  
K. -H. Feger ◽  
G. Brahmer ◽  
H. W. Zöttl
Keyword(s):  
Black Forest ◽  
Element Cycling
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