scholarly journals Carbon acquisition in a Baltic pico-phytoplankton species - Where does the carbon for growth come from?

2020 ◽  
Author(s):  
Luisa Listmann ◽  
Franziska Kerl ◽  
Nele Martens ◽  
C-Elisa Schaum
Keyword(s):  
Organic Carbon ◽  
Environmental Change ◽  
Growth Curve ◽  
Primary Productivity ◽  
Growth Rates ◽  
Net Primary Productivity ◽  
List Type ◽  
Bornholm Basin ◽  
Potential Growth ◽  
North East

Summary- Pico-phytoplankton have ample scope to react to environmental change. But we know little about the underlying physiological mechanisms that govern how evolutionary history may affect short-term responses to environmental change.- We investigated growth rates and carbon uptake related traits (i.e. fitness proxies) in different temperatures and at different times during the microbial growth curve of eight novel strains of Ostreococcus sp. (ca. 1-2µm). The strains were isolated from two distinct regions of the Baltic Sea differing in salinity and temperature from North-East (Bornholm Basin) to South-West (Kiel area).- Strains from the warmer, more variable Kiel area had higher growth rates in general and showed more variable growth rates compared to strains from the colder and less variable Bornholm Basin.- In addition, growth was maintained in early stages of the growth curve by organic carbon acquisition and the increase in growth over time and with temperature was associated with an increase in inorganic carbon acquisition (net primary productivity).- Based on the differences between net primary productivity and potential growth on organic carbon, we postulate a shift in carbon acquisition between inorganic and organic sources in Ostreococcus sp. with potential implications on ecological dynamics within microbial communities.

scholarly journals Differences in Carbon Acquisition Could Explain Adaptive Responses in a Baltic Sea Pico-Phytoplankton

2021 ◽  
Vol 8 ◽  
Author(s):  
Luisa Listmann ◽  
Franziska Kerl ◽  
Nele Martens ◽  
C-Elisa Schaum
Keyword(s):  
Organic Carbon ◽  
Environmental Change ◽  
Baltic Sea ◽  
Growth Curve ◽  
Growth Rates ◽  
Carbon Sources ◽  
Lag Phase ◽  
Limiting Factor ◽  
Bornholm Basin ◽  
North East

Pico-phytoplankton have ample scope to react to environmental change. Nevertheless, we know little about the underlying physiological mechanisms that govern how evolutionary history may affect short-term responses to environmental change. We investigated growth rates and carbon uptake related traits at 15° and 22°C and at different times during the microbial growth curve (lag phase, mid and late exponential) of eight novel strains of Ostreococcus sp. (ca. 1 μm). The strains were isolated from two distinct regions of the Baltic Sea differing in salinity and temperature as well as variability therein from North-East (Bornholm Basin) to South-West (Kiel area). Strains from Kiel area had ca. 10% higher growth rates on average and showed more variation between strains compared to strains from the Bornholm Basin. While biomass increased throughout the experiment in both temperature, CUE (carbon use efficiency, indicative of photosynthetically derived carbon available for growth) was too low to explain positive growth throughout the entire growth curve at 15°C and during the early stages at 22°C. Throughout the growth curve CUE then increased enough to sustain growth, but only at 22°C. Consequently, we then tested whether Ostreococcus use organic carbon to supplement growth when light is not a limiting factor. We show that Ostreococcus qualitatively modulate their potential to grow on organic carbon sources throughout a single growth curve. Based on the differences between CUE and a potential to grow on organic carbon, we postulate a shift in carbon acquisition between inorganic and organic sources in Ostreococcus sp. with potential implications on ecological dynamics within microbial communities.

scholarly journals Divergent controls of soil organic carbon between observations and process-based models

2021 ◽  
Author(s):  
Katerina Georgiou ◽  
Avni Malhotra ◽  
William R. Wieder ◽  
Jacqueline H. Ennis ◽  
Melannie D. Hartman ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Global Scale ◽  
Mean Annual Temperature ◽  
Biogeochemical Models ◽  
Soc Stocks ◽  
Process Based Models

AbstractThe storage and cycling of soil organic carbon (SOC) are governed by multiple co-varying factors, including climate, plant productivity, edaphic properties, and disturbance history. Yet, it remains unclear which of these factors are the dominant predictors of observed SOC stocks, globally and within biomes, and how the role of these predictors varies between observations and process-based models. Here we use global observations and an ensemble of soil biogeochemical models to quantify the emergent importance of key state factors – namely, mean annual temperature, net primary productivity, and soil mineralogy – in explaining biome- to global-scale variation in SOC stocks. We use a machine-learning approach to disentangle the role of covariates and elucidate individual relationships with SOC, without imposing expected relationships a priori. While we observe qualitatively similar relationships between SOC and covariates in observations and models, the magnitude and degree of non-linearity vary substantially among the models and observations. Models appear to overemphasize the importance of temperature and primary productivity (especially in forests and herbaceous biomes, respectively), while observations suggest a greater relative importance of soil minerals. This mismatch is also evident globally. However, we observe agreement between observations and model outputs in select individual biomes – namely, temperate deciduous forests and grasslands, which both show stronger relationships of SOC stocks with temperature and productivity, respectively. This approach highlights biomes with the largest uncertainty and mismatch with observations for targeted model improvements. Understanding the role of dominant SOC controls, and the discrepancies between models and observations, globally and across biomes, is essential for improving and validating process representations in soil and ecosystem models for projections under novel future conditions.

How plastic mulching affects net primary productivity, soil C fluxes and organic carbon balance in dry agroecosystems in China

2020 ◽  
Vol 263 ◽  
pp. 121470
Author(s):  
Fei Mo ◽  
Kai-Liang Yu ◽  
Thomas W. Crowther ◽  
Jian-Yong Wang ◽  
Hong Zhao ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Primary Productivity ◽  
Carbon Balance ◽  
Net Primary Productivity ◽  
Soil C ◽  
Plastic Mulching

scholarly journals Non-Flat Earth Recalibrated for Terrain and Topsoil

Soil Systems ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 64 ◽  
Author(s):  
Robert Blakemore
Keyword(s):  
Organic Carbon ◽  
Primary Productivity ◽  
Land Surface ◽  
Net Primary Productivity ◽  
Lidar Data ◽  
Vam Fungi ◽  
Empirical Estimates ◽  
Digital Elevation ◽  
Vesicular Arbuscular ◽  
Global Soil

Earth’s land surface is raised from conventionally flat 15 Gha to >64 Gha accounting for hilly slope undulation and topsoil relief detail. Three main aspects are: topography, rugosity/tortuosity, and micro-relief/porosity of ice/vegetation-free ground. Recalibration arises from four approaches: First, direct empirical estimates of compiled satellite/LiDAR data means of +2.5–26% surface progressively overlain by +94% at cm2 scale for soil ruggedness then +108% for mm2 micro-relief; Second, from digital elevation models with thrice 1.6–2.0 times flat areas; Third, by ‘reverse engineering’ global soil bulk densities and carbon reserves requiring ×4–6 land. Finally, a Fermi estimation doubles the Earth’s surface—as exposed to Sun, air and rain—conveniently set at 100 Gha (with 64 Gha land:36 Gha ocean). Soil organic carbon (SOC) thereby grows to 8580 Gt mainly in SOM-humus with its biotic complexity plus roots, Vesicular-Arbuscular Mycorrhiza (VAM-fungi), leaf-litter and earthworms itself totaling 17,810 Gt. Although four to six times IPCC’s or NASA/NOAA’s calculated 1500–2300 Gt SOC, this is likely an underestimation. Global biomass and biodiversity are at least doubled (×2–3.5) and net primary productivity (NPP) increases to >270 Gt C yr−1 due to terrain. Rationale for a ‘Soil Ecology Institute’ gains ground.

scholarly journals Global patterns and climatic controls of belowground net carbon fixation

2020 ◽  
Vol 117 (33) ◽  
pp. 20038-20043 ◽  
Author(s):  
Laureano A. Gherardi ◽  
Osvaldo E. Sala
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Primary Production ◽  
Primary Productivity ◽  
Carbon Fixation ◽  
Net Primary Productivity ◽  
Net Primary Production ◽  
Belowground Carbon ◽  
Belowground Productivity ◽  
Carbon Productivity

Carbon allocated underground through belowground net primary production represents the main input to soil organic carbon. This is of significant importance, because soil organic carbon is the third-largest carbon stock after oceanic and geological pools. However, drivers and controls of belowground productivity and the fraction of total carbon fixation allocated belowground remain uncertain. Here we estimate global belowground net primary productivity as the difference between satellite-based total net primary productivity and field observations of aboveground net primary production and assess climatic controls among biomes. On average, belowground carbon productivity is estimated as 24.7 Pg y−1, accounting for 46% of total terrestrial carbon fixation. Across biomes, belowground productivity increases with mean annual precipitation, although the rate of increase diminishes with increasing precipitation. The fraction of total net productivity allocated belowground exceeds 50% in a large fraction of terrestrial ecosystems and decreases from arid to humid ecosystems. This work adds to our understanding of the belowground carbon productivity response to climate change and provides a comprehensive global quantification of root/belowground productivity that will aid the budgeting and modeling of the global carbon cycle.

scholarly journals Global environmental change and the nature of aboveground net primary productivity responses: insights from long-term experiments

Oecologia ◽  
2015 ◽  
Vol 177 (4) ◽  
pp. 935-947 ◽  
Author(s):  
Melinda D. Smith ◽  
Kimberly J. La Pierre ◽  
Scott L. Collins ◽  
Alan K. Knapp ◽  
Katherine L. Gross ◽  
...  
Keyword(s):  
Environmental Change ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Global Environmental Change ◽  
Aboveground Net Primary Productivity ◽  
Global Environmental ◽  
Long Term Experiments
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