Coupling of nutrient cycling and carbon dynamics in the Arctic, integration of soil microbial and plant processes

1999 ◽  
Vol 11 (2-3) ◽  
pp. 135-146 ◽  
Author(s):  
Sven Jonasson ◽  
Anders Michelsen ◽  
Inger K Schmidt
Keyword(s):  
Nutrient Cycling ◽  
Carbon Dynamics ◽  
The Arctic ◽  
Soil Microbial

scholarly journals Labile carbon limits late winter microbial activity near Arctic treeline

2020 ◽  
Author(s):  
Patrick F. Sullivan ◽  
Madeline C. Stokes ◽  
Cameron K. McMillan ◽  
Michael N. Weintraub
Keyword(s):  
Nutrient Cycling ◽  
Microbial Activity ◽  
Microbial Respiration ◽  
Soil Microbial Communities ◽  
The Arctic ◽  
Late Winter ◽  
Soil Microbial ◽  
Arctic Soils ◽  
Labile C ◽  
Soil Temperatures

It is well established that soil microbial communities remain active during much of the Arctic winter, despite soil temperatures that are often well below −10°C1. Overwinter microbial activity has important effects on global carbon (C) budgets2, nutrient cycling and vegetation community composition3. Microbial respiration is highly temperature sensitive in frozen soils, as liquid water and solute availability decrease rapidly with declining temperature4. Thus, temperature is considered the ultimate control on overwinter soil microbial activity in the Arctic. Warmer winter soils are thought to yield greater microbial respiration of available C, greater overwinter CO2 efflux and a flush of nutrients that could be available for plant uptake at thaw3. Rising air temperature, combined with changes in timing and/or depth of snowpack development, is leading to warmer Arctic winter soils5. Using observational and experimental approaches in the field and in the laboratory, we demonstrate that persistently warm winter soils can lead to labile C starvation of the microbial community and reduced respiration rates, despite the high C content of most arctic soils. If Arctic winter soil temperatures continue to rise, microbial C limitation will reduce cold season CO2 emissions and alter soil nutrient cycling, if not countered by greater labile C inputs.

scholarly journals Arctic riparian shrub expansion indicates a shift from streams gaining water to those that lose flow

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Anna K. Liljedahl ◽  
Ina Timling ◽  
Gerald V. Frost ◽  
Ronald P. Daanen
Keyword(s):  
Microbial Communities ◽  
Soil Microbial Communities ◽  
Late Summer ◽  
Field Measurements ◽  
The Arctic ◽  
Shrub Expansion ◽  
Riparian Ecosystems ◽  
Stream Length ◽  
Area Index ◽  
Soil Microbial

AbstractShrub expansion has been observed across the Arctic in recent decades along with warming air temperatures, but tundra shrub expansion has been most pronounced in protected landscape positions such as floodplains, streambanks, water tracks, and gullies. Here we show through field measurements and laboratory analyses how stream hydrology, permafrost, and soil microbial communities differed between streams in late summer with and without tall shrubs. Our goal was to assess the causes and consequences of tall shrub expansion in Arctic riparian ecosystems. Our results from Toolik Alaska, show greater canopy height and density, and distinctive plant and soil microbial communities along stream sections that lose water into unfrozen ground (talik) compared to gaining sections underlain by shallow permafrost. Leaf Area Index is linearly related to the change in streamflow per unit stream length, with the densest canopies coinciding with increasingly losing stream sections. Considering climate change and the circumpolar scale of riparian shrub expansion, we suggest that permafrost thaw and the resulting talik formation and shift in streamflow regime are occurring across the Low Arctic.

scholarly journals Soil microbial biomass, activity and community composition along altitudinal gradients in the High Arctic (Billefjorden, Svalbard)

2018 ◽  
Vol 15 (6) ◽  
pp. 1879-1894 ◽  
Author(s):  
Petr Kotas ◽  
Hana Šantrůčková ◽  
Josef Elster ◽  
Eva Kaštovská
Keyword(s):  
Community Structure ◽  
Microbial Biomass ◽  
High Arctic ◽  
The Arctic ◽  
Soil Parameters ◽  
Organic Carbon Content ◽  
Soil Microbial ◽  
Environmental Controls ◽  
Arctic Soils ◽  
Tundra Ecosystem

Abstract. The unique and fragile High Arctic ecosystems are vulnerable to global climate warming. The elucidation of factors driving microbial distribution and activity in arctic soils is essential for a comprehensive understanding of ecosystem functioning and its response to environmental change. The goals of this study were to investigate microbial biomass and activity, microbial community structure (MCS), and their environmental controls in soils along three elevational transects in the coastal mountains of Billefjorden, central Svalbard. Soils from four different altitudes (25, 275, 525 and 765 m above sea level) were analyzed for a suite of characteristics including temperature regimes, organic matter content, base cation availability, moisture, pH, potential respiration, and microbial biomass and community structure using phospholipid fatty acids (PLFAs). We observed significant spatial heterogeneity of edaphic properties among transects, resulting in transect-specific effects of altitude on most soil parameters. We did not observe any clear elevation pattern in microbial biomass, and microbial activity revealed contrasting elevational patterns between transects. We found relatively large horizontal variability in MCS (i.e., between sites of corresponding elevation in different transects), mainly due to differences in the composition of bacterial PLFAs, but also a systematic altitudinal shift in MCS related to different habitat preferences of fungi and bacteria, which resulted in high fungi-to-bacteria ratios at the most elevated sites. The biological soil crusts on these most elevated, unvegetated sites can host microbial assemblages of a size and activity comparable to those of the arctic tundra ecosystem. The key environmental factors determining horizontal and vertical changes in soil microbial properties were soil pH, organic carbon content, soil moisture and Mg2+ availability.

scholarly journals Identification of new microbial functional standards for soil quality assessment

2019 ◽  
Author(s):  
Sören Thiele-Bruhn ◽  
Michael Schloter ◽  
Berndt-Michael Wilke ◽  
Lee A. Beaudette ◽  
Fabrice Martin-Laurent ◽  
...  
Keyword(s):  
Plant Growth ◽  
Nutrient Cycling ◽  
Greenhouse Gas ◽  
Soil Quality ◽  
Plant Growth Promotion ◽  
Ecosystem Service ◽  
Enzyme Activities ◽  
Growth Promotion ◽  
Soil Microbial ◽  
Microbiological Methods

Abstract. The activity of microorganisms in soil is important for a robust functioning soil and related ecosystem service. Hence, there is a necessity to identify the indigenous soil microbial community for its functional properties using soil microbiological methods in order to determine the natural properties, functioning and operating range of soil microbial communities, and to assess ecotoxicological effects due to anthropogenic activities. Numerous microbiological methods currently exist in the literature and new, more advanced methods continue to be developed; however, only a limited number of the methods are standardized. Consequently, there is a need to identify the most promising non-standardized methods for assessing soil quality and develop these into standards. In alignment with the "Ecosystem Service Approach", new methods should focus on soil microbial function, including nutrient cycling, pest control and plant growth promotion, carbon cycling and sequestration, greenhouse gas emission, and soil structure. The few existing, function-related standard methods available focus on the estimation of microbial biomass, basal respiration, enzyme activities related to nutrient cycling, and organic chemical biodegradation. This paper sets out to summarize and expand on recent discussions within the International Organization for Standardization (ISO), Soil Quality - Biological Characterization sub-committee (ISO TC 190/SC 4) where a need was identified to develop scientifically sound methods which would best fulfil the practical needs of future users for assessing soil quality. Of particular note was the current evolution of molecular methods in microbial ecology that uses quantitative real time PCR (qPCR) to produce a large number of new endpoints and is more sensitive as compared to "classical" methods. Quantitative PCR assesses the activity of microbial genes that code for enzymes that catalyse major transformation steps in nitrogen and phosphorus cycling, greenhouse gas emissions, chemical transformations including pesticide degradation, and plant growth promotion pathways. In the assessment of soil quality methods, it was found that fungal methods were significantly underrepresented. As such, techniques to analyse fungal enzyme activities are proposed. Additionally, methods for the determination of microbial growth rates and efficiencies, including the use of glomalin as a biochemical marker for soil aggregation, are discussed. Furthermore, field methods indicative of carbon turnover, including the litter bag test and a modification to the tea bag test, are presented. As a final note, it is suggested that endpoints should represent a potential function of soil microorganisms rather than actual activity levels, as the latter can largely be dependent on short-term variable soil properties such as pedoclimatic conditions, nutrient availability, and anthropogenic soil cultivation activities.

Effect of Drought and Recovery on Grazing Animal, Microbial, and Fungal Response in a Diverse Multi-Crop Rotation

2020 ◽  
Author(s):  
Douglas Landblom ◽  
Songul Senturklu
Keyword(s):  
Nutrient Cycling ◽  
Beef Cattle ◽  
Microbial Activity ◽  
Crop Rotation ◽  
Cover Crop ◽  
Crop Production ◽  
Microbial Respiration ◽  
Soil Nutrient ◽  
Soil Microbial ◽  
Animal Grazing

<p>Beef cattle grazing, soil microbial respiration, and Rhizobia spp. populations serve important roles in soil nutrient cycling and during periods of drought, when abnormal precipitation declines, forage production for animal grazing and performance are negatively impacted. Soil nutrient availability is essential for adequate crop production and extended drought reduces soil microbial activity and therefore nutrient cycling. During the 2017 growing season between April and October in the northern Great Plains region of the USA, effective precipitation for crop production and animal grazing was severely reduced due an exceptional drought as classified by the US Drought Monitor. At the NDSU – Dickinson Research Extension Center, Dickinson, North Dakota, USA, a long-term integrated system that includes yearling steer grazing within a diverse multi-crop rotation (spring wheat, cover crop, corn, pea-barley intercrop, and sunflower). Within the rotation of cash and forage crops, beef cattle graze the pea-barley, corn, and cover crop (13-specie) within the rotation and is being utilized to monitor the effects of animal, microbial and fungal activity over time and space in the crop and animal production system. Nitrogen fertilizer has been replaced in the system by soil microbial and fungal activity (Potential Mineralizable Nitrogen: 8.4 mg N/kg) such that for each 1% increase in SOM there is a corresponding increase of 18.8 kg of potential nitrogen mineralized per ha. Animal grazing days are severely reduced when precipitation is inadequate for soil microbial respiration to occur. What is even more concerning, when relying on microbial activity to supply plant nutrients, is recovery time for microbial activity to fully recover from exceptional drought as was the case in this research project. Compared to the 2016 crop production year that preceded the 2017 drought, cover crop (13-specie), pea-barley, and corn yields were reduced 86, 33, and 64% during the 2017 drought. This decline in crop production reduced the number of days of grazing by an average 50% and average daily gains were also reduced. Steer average daily gains were 1.05 0.95, and 0.83 kg/steer/day in 2017 when grazing pea-barley, corn, and cover crop, respectively. For this research that relies on soil derived plant nutrients soil analysis for microbial and Rhizobia spp. biomass began recovery in 2018 and continued into 2019 as evidenced by large percentage increases in organism biomass; however, complete production recovery did not occur by the end of the 2019 grazing season in which days of grazing were reduced compared to the 2016 grazing season. Biological animal, crop, microbial, fungal, and nutrient replacement recovery will be presented in the poster.</p>

scholarly journals Filtered mud improves sugarcane growth and modifies the functional abundance and structure of soil microbial populations

PeerJ ◽  
2022 ◽  
Vol 10 ◽  
pp. e12753
Author(s):  
Ahmad Yusuf Abubakar ◽  
Muhammed Mustapha Ibrahim ◽  
Caifang Zhang ◽  
Muhammad Tayyab ◽  
Nyumah Fallah ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
High Throughput ◽  
High Throughput Sequencing ◽  
Soil Nutrient ◽  
Clay Loam ◽  
Sugarcane Production ◽  
Bacterial Phyla ◽  
Soil Microbial ◽  
Soil Nutrient Cycling ◽  
Growth Properties

Background Exploring high-quality organic amendments has been a focus of sustainable agriculture. Filtered mud (FM), a sugar factory waste derived from sugarcane stems, could be an alternative organic amendment for sugarcane production. However, the effects of its application proportions on soil fertility, nutrient cycling, structure of soil bacterial and fungal communities, and the growth of sugarcane in clay-loam soils remain unexplored. Methods Three application proportions of FM: (FM1-(FM: Soil at 1:4), FM2-(FM: Soil at 2:3), and FM3-(FM: Soil at 3:2)) were evaluated on sugarcane growth and soil nutrient cycling. High throughput sequencing was also employed to explore soil microbial dynamics. Results We observed that FM generally increased the soil’s nutritional properties while improving NO3− retention compared to the control, resulting in increased growth parameters of sugarcane. Specifically, FM1 increased the concentration of NH4+−N, the N fraction preferably taken up by sugarcane, which was associated with an increase in the plant height, and more improved growth properties, among other treatments. An increase in the proportion of FM also increased the activity of soil nutrient cycling enzymes; urease, phosphatase, and β-glucosidase. High throughput sequencing revealed that FM reduced the diversity of soil bacteria while having insignificant effects on fungal diversity. Although increasing FM rates reduced the relative abundance of the phyla Proteobacteria, its class members, the Gammaproteobacteria and Betaproteobacteria containing some N-cycling related genera, were stimulated. Also, FM stimulated the abundance of beneficial and lignocellulose degrading organisms. These included the bacterial phyla Actinobacteria, Bacteroidetes, Acidobacteria, Chloroflexi, and the fungal phylum Ascomycota. The distribution of the soil microbial community under FM rates was regulated by the changes in soil pH and the availability of soil nutrients. Since FM1 showed more promise in improving the growth properties of sugarcane, it could be more economical and sustainable for sugarcane production in clay-loam soils.

scholarly journals Arctic Survey Hunts for Missing Nitrogen and Phosphorus

Eos ◽  
2016 ◽  
Vol 97 ◽  
Author(s):  
David Shultz
Keyword(s):  
Nutrient Cycling ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
The Arctic ◽  
Nitrogen And Phosphorus ◽  
Shed Light

A new survey of ocean waters flowing in and out of the Arctic may shed light on how dissolved organic nitrogen and phosphorus contribute to nutrient cycling in the Arctic.

scholarly journals Intracellular Storage Reduces Stoichiometric Imbalances in Soil Microbial Biomass – A Theoretical Exploration

2021 ◽  
Vol 9 ◽  
Author(s):  
Stefano Manzoni ◽  
Yang Ding ◽  
Charles Warren ◽  
Callum C. Banfield ◽  
Michaela A. Dippold ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Nutrient Cycling ◽  
Theoretical Perspective ◽  
Nutrient Retention ◽  
Model Parameters ◽  
Soil C ◽  
Soil Microbial ◽  
Pulse Experiment ◽  
Intracellular Storage

Microbial intracellular storage is key to defining microbial resource use strategies and could contribute to carbon (C) and nutrient cycling. However, little attention has been devoted to the role of intracellular storage in soil processes, in particular from a theoretical perspective. Here we fill this gap by integrating intracellular storage dynamics into a microbially explicit soil C and nutrient cycling model. Two ecologically relevant modes of storage are considered: reserve storage, in which elements are routed to a storage compartment in proportion to their uptake rate, and surplus storage, in which elements in excess of microbial stoichiometric requirements are stored and limiting elements are remobilized from storage to fuel growth and microbial maintenance. Our aim is to explore with this model how these different storage modes affect the retention of C and nutrients in active microbial biomass under idealized conditions mimicking a substrate pulse experiment. As a case study, we describe C and phosphorus (P) dynamics using literature data to estimate model parameters. Both storage modes enhance the retention of elements in microbial biomass, but the surplus storage mode is more effective to selectively store or remobilize C and nutrients according to microbial needs. Enhancement of microbial growth by both storage modes is largest when the substrate C:nutrient ratio is high (causing nutrient limitation after substrate addition) and the amount of added substrate is large. Moreover, storage increases biomass nutrient retention and growth more effectively when resources are supplied in a few large pulses compared to several smaller pulses (mimicking a nearly constant supply), which suggests storage to be particularly relevant in highly dynamic soil microhabitats. Overall, our results indicate that storage dynamics are most important under conditions of strong stoichiometric imbalance and may be of high ecological relevance in soil environments experiencing large variations in C and nutrient supply.

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