scholarly journals Horizontal heterogeneity of seston, organic carbon and picoplankton in the photic zone of Lago Maggiore, Northern Italy

2004 ◽  
Vol 63 (2) ◽  
pp. 244 ◽  
Author(s):  
Roberto BERTONI ◽  
Roberta PISCIA ◽  
Cristiana CALLIERI
Keyword(s):  
Organic Carbon ◽  
Northern Italy ◽  
Photic Zone ◽  
Horizontal Heterogeneity

Alternatives to Glyphosate in conservation agriculture: effects on carbon sequestration in a field experiment in northern Italy

2020 ◽  
Author(s):  
alessia perego ◽  
marco acutis ◽  
calogero schillaci
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Field Experiment ◽  
Biomass Production ◽  
Cover Crops ◽  
Management Practices ◽  
Block Design ◽  
Northern Italy ◽  
Cash Crop

<p>Conservative Agriculture (CA) practices are recognized to enhance soil organic carbon stock and in turn to mitigate the effect of climate change. One of the CA principles is to integrate cover crops (CC) into the cropping systems. The termination of CC before the cash crop sowing and the weeds control are the most critical aspects to manage in the CA. The technique currently adopted by farmers for the termination of CC implies the use of Glyphosate. However, the European Commission is currently discussing the possibility of banning the use of this herbicide due to the negative effects on human health and the agro-environment. The disk harrow (DH) or the roller-crimper (RC) can be adopted in CA as an alternative to the use of Glyphosate for the devitalization of CC, their incorporation into the soil (in the case of the disk harrow), and the reduction of weed pressure on the subsequent cash crop.</p><p>From November 2017 to October 2019, soil organic carbon (SOC, g kg<sup>-1</sup>) and crop biomass production were observed in a 2-year field experiment located in Lodi (northern Italy), in which minimum tillage (MT) has been applied for the last 5 years. The soil was loamy and SOC was 16.2 g kg<sup>-1</sup> at the beginning of the experiment. The winter CC was barley (from November to May) and the cash crop was soybean (from June to October). The experiment consisted in three treatments replied for two consecutive years in a randomized block design: Glyphosate spray + DH + sowing + hoeing (MT-GLY); DH + sowing + hoeing (MT-ORG); RC + sod seeding (NT-ORG).</p><p>At the end of 2019, SOC resulted in a higher increase in MT-GLY (+15%) and in MT-ORG (+14%) than in NT-ORG (+6%; p<0.01). This was due to the fact that CC litter in NT-ORG was not in direct contact with soil particles and the process of immobilization was lower than in the other treatments.</p><p>Moreover, the increase in SOC resulted positively correlated to the CC biomass (2018+2019), which was significantly lower in NT-ORG. In particular, no differences of soybean and CC between the three treatments were observed at the end of 2018, but MT-GLY resulted in significantly higher CC and soybean biomass at the end of the second year (+32%, p<0.01). MT-GLY allows to stock more carbon via photosynthesis that in turn results in higher SOC content.</p><p>However, if we consider the tractor fuel consumption (for Glyphosate spray, DH, RC, hoeing), along with the biomass production, the carbon sequestration did not vary between the three treatments.</p><p>Further studies are needed for the definition of optimized field management practices to reduce the passage of machinery while increasing crop production and SOC.</p>

scholarly journals Soil Carbon Investigation in Three Pedoclimatic and Agronomic Settings of Northern Italy

2020 ◽  
Vol 12 (24) ◽  
pp. 10539
Author(s):  
Valentina Brombin ◽  
Enrico Mistri ◽  
Mauro De Feudis ◽  
Camilla Forti ◽  
Gian Marco Salani ◽  
...  
Keyword(s):  
Organic Carbon ◽  
C Sequestration ◽  
Soil Microbial Activity ◽  
Soil Disturbance ◽  
Northern Italy ◽  
Cold Climate ◽  
Soil C ◽  
Organic Farm ◽  
Soil Sustainability ◽  
Soil C Sequestration

Sustainable agricultural management is needed to promote carbon (C) sequestration in soil, prevent loss of soil fertility, and reduce the release of greenhouse gases. However, the influence of agronomic practices on soil C sequestration depends on the existing pedoclimatic features. We characterized the soils of three farms far away each other in the Emilia-Romagna region (Northern Italy): an organic farm in the Northern Apennines, a biodynamic farm, and a conventional farm on the Po Plain. The total, inorganic, and organic carbon in soil, as well as the distinct humic fractions were investigated, analyzing both the elemental and isotopic (13C/12C) composition. In soils, organic matter appears to be variously affected by mineralization processes induced by microorganisms that consume organic carbon. In particular, organic carbon declined in farms located in the plain (e.g., organic carbon down to 0.75 wt%; carbon stock0-30 cm down to 33 Mg/ha), because of the warmer climate and moderately alkaline environment that enhance soil microbial activity. On the other hand, at the mountain farm, the minimum soil disturbance, the cold climate, and the neutral conditions favored soil C sequestration (organic carbon up to 4.42 wt%; carbon stock0-30 cm up to 160 Mg/ha) in humified organic compounds with long turnover, which can limit greenhouse gas emissions into the atmosphere. This work shows the need for thorough soil investigations, to propose tailored best-practices that can reconcile productivity and soil sustainability.

Cycling of organic carbon in the photic zone of a eutrophic lake with special reference to the heterotrophic bacteria

1989 ◽  
Vol 34 (5) ◽  
pp. 840-855 ◽  
Author(s):  
Olav Vadstein ◽  
Bjørn Ola Harkjerr ◽  
Arne Jensen ◽  
Yngvar Olsen ◽  
Helge Reinertsen
Keyword(s):  
Organic Carbon ◽  
Special Reference ◽  
Heterotrophic Bacteria ◽  
Eutrophic Lake ◽  
Photic Zone

Soil Organic Carbon Variation in Alpine Landscape (Northern Italy) as Evaluated by Diffuse Reflectance Spectroscopy

2014 ◽  
Vol 78 (3) ◽  
pp. 794-804 ◽  
Author(s):  
Claudio Colombo ◽  
Giuseppe Palumbo ◽  
Erika Di Iorio ◽  
Vincenzo Michele Sellitto ◽  
Roberto Comolli ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
Northern Italy ◽  
Alpine Landscape

Biomarker evidence of algal-microbial community changes linked to redox and salinity variation, Upper Devonian Chattanooga Shale (Tennessee, USA)

2020 ◽  
Vol 133 (1-2) ◽  
pp. 409-424 ◽  
Author(s):  
Yi Song ◽  
Geoffrey J. Gilleaudeau ◽  
Thomas J. Algeo ◽  
D. Jeffrey Over ◽  
Timothy W. Lyons ◽  
...  
Keyword(s):  
Microbial Community ◽  
Organic Carbon ◽  
Upper Devonian ◽  
Photic Zone ◽  
Sharp Reduction ◽  
Green Algal ◽  
Chattanooga Shale ◽  
Lipid Biomarker ◽  
Community Changes ◽  
Microalgal Community

Abstract Late Devonian marine systems were characterized by major environmental perturbations and associated biotic community changes linked to climate change and widespread oceanic anoxia. Here, we provide high-resolution lipid biomarker chemostratigraphic records from the Upper Devonian Chattanooga Shale (Tennessee, USA) to investigate algal-microbial community changes in the southern Illinois Basin that were related to contemporaneous shifts in marine redox (as proxied by trace metals, Fe-species, and Corg/P) and salinity conditions (as proxied by B/Ga, Sr/Ba, and S/total organic carbon). The Frasnian was characterized by dominantly bacterial lipids (high hopane/sterane), near-marine salinity, and a shift from oxic to increasingly reducing conditions in response to increasing organic carbon sinking fluxes. Aryl isoprenoids and aryl isoprenoid ratios reveal that the O2-H2S chemocline was unstable and intermittently shallow (i.e., within the photic zone). The Frasnian-Famennian boundary was marked by a shift in microalgal community composition toward green algal (e.g., prasinophyte) dominance (lower C27 and higher C28 and C29 steranes), a sharp reduction in watermass salinity, and a stable O2-H2S chemocline below the photic zone, conditions that persisted until nearly the end of the Famennian. We infer that changing watermass conditions, especially a sharp reduction in salinity to possibly low-brackish conditions (<10 psu), were the primary cause of concurrent changes in the microalgal community, reflecting tolerance of low-salinity conditions by green algae. Transient spikes in moretane/hopane (M/H) ratios may record enhanced terrestrial weathering at the Frasnian-Famennian and Devonian–Carboniferous boundaries, triggered by coeval glacio-eustatic falls and increased inputs of soil organic matter. High M/H and pristane/phytane, in combination with low chemical index of alteration and K/Al, record a decrease in chemical weathering intensity during the Famennian that may have been due to contemporaneous climatic cooling, and a concurrent reduction in silt content may reflect stabilization of land surfaces by vascular plants and resulting reduced sediment yields. This study demonstrates the effectiveness of combining organic and inorganic geochemical proxies (including novel paleosalinity indices) for determination of environmental controls on the composition and productivity of plankton communities in paleomarine systems.

scholarly journals Impact of the Paleoclimate, Paleoenvironment, and Algae Bloom: Organic Matter Accumulation in the Lacustrine Lucaogou Formation of Jimsar Sag, Junggar Basin, NW China

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1488 ◽  
Author(s):  
Yuhan Jiang ◽  
Dujie Hou ◽  
Hang Li ◽  
Ziming Zhang ◽  
Ruibo Guo
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Water Column ◽  
Shale Oil ◽  
Photic Zone ◽  
Sweet Spot ◽  
Algae Bloom ◽  
Organic Matter Accumulation ◽  
Lucaogou Formation ◽  
Water Stratification

Shale oil exploration has been a key area of onshore oil and gas exploration in China in recent years. In this study, organic geochemistry and element geochemistry are united to study the shale oil and source rock in the Lucaogou formation of Jimusar sag, in order to reveal the paleoclimate, paleoenvironment, source of organic matter, and factors affecting organic matter accumulation and shale oil generation. The shale oil in the study area is mainly accumulated in two strata with good reservoir properties and oiliness, known as the upper sweet spot and lower sweet spot. Indexes of biomarkers and sensitive elements revealed the warm and semi-arid paleoclimate during Lucaogou formation, and the water column was brackish to salty. Water stratification caused a suboxic to anoxic environment in the deep-water column and coincided with the anoxic photic zone phenomenon. Compared with the lower sweet spot, the more humid climate, deeper and fresher water, and stronger water stratification characterize the upper sweet spot during sedimentation. This made the photic zone with freshwater more suitable for the reproduction of algae in the upper sweet spot. Meanwhile, the organic matter was well-preserved in the anoxic zone. Volcanic ash caused algae bloom, which promoted primary productivity and ensured the supply of organic matter. The composition and distribution pattern of biomarkers prove that phytoplankton is the most important source of organic matter in the study area and the contribution of higher plants is insignificant. The relationship between parameters of paleoproductivity and the redox condition versus total organic carbon (TOC) suggests that compared with the preservation conditions, the input of organic carbon is the most important controlling factor of organic matter accumulation in the study area.

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