ASSESSMENT OF BIOTURBATION ACTIVITY OF MARENZELLERIA SPP. IN THE EASTERN PART OF THE GULF OF FINLAND

Author(s):  
Ekaterina Voloshchuk ◽  
Ekaterina Voloshchuk ◽  
Tatjana Eremina ◽  
Tatjana Eremina ◽  
Alexey Isaev ◽  
...  

Macrofauna is supposed to influence on physic-chemical characteristics of the sea bottom sediments. Through its bioturbation mechanism porosity, area of oxygenated layer and oxygen penetration depth have increased. This lead to alterations in nutrient cycling as well as improvement in redox conditions which define direction of fluxes in the sediments. In oxic conditions phosphorus is transformed into particulate form and thus, its retention and burial increase. In contrary, denitrification is getting weaker and nitrogen returns into the water. The impact of benthic organisms bioirrigation activity on other chemical components in solid sediments is not sufficiently studied. Present investigations were carried out for the most abundant benthic species in the Gulf of Finland Marenzelleria spp. Those polychaetes are active turbators and their irrigation effect lead to significant changes in chemical compounds in the solid sediment. On the basis of statistical analysis of data on vertical distribution of organic carbon content, total iron and manganese in solid sediments and abundance of Marenzelleria spp. there was found that polychaetes have a significant impact on organic carbon content, while for total iron and manganese such regularity is not revealed.

Author(s):  
Ekaterina Voloshchuk ◽  
Ekaterina Voloshchuk ◽  
Tatjana Eremina ◽  
Tatjana Eremina ◽  
Alexey Isaev ◽  
...  

Macrofauna is supposed to influence on physic-chemical characteristics of the sea bottom sediments. Through its bioturbation mechanism porosity, area of oxygenated layer and oxygen penetration depth have increased. This lead to alterations in nutrient cycling as well as improvement in redox conditions which define direction of fluxes in the sediments. In oxic conditions phosphorus is transformed into particulate form and thus, its retention and burial increase. In contrary, denitrification is getting weaker and nitrogen returns into the water. The impact of benthic organisms bioirrigation activity on other chemical components in solid sediments is not sufficiently studied. Present investigations were carried out for the most abundant benthic species in the Gulf of Finland Marenzelleria spp. Those polychaetes are active turbators and their irrigation effect lead to significant changes in chemical compounds in the solid sediment. On the basis of statistical analysis of data on vertical distribution of organic carbon content, total iron and manganese in solid sediments and abundance of Marenzelleria spp. there was found that polychaetes have a significant impact on organic carbon content, while for total iron and manganese such regularity is not revealed.


Author(s):  
Ian R. Napier

The dry weight and organic carbon content of eggs and components of Clyde spring herring eggs were measured at intervals during their development. Comparison with previously published data suggests that an increase has occurred in the weight of these eggs over the past thirty years. It is clear that only a small proportion of the material deposited in the form of herring spawn actually remains attached to the substratum when the larvae hatch and so is available for potential integration into the benthic food web. This was confirmed by the determination at intervals over two years of the organic carbon content of the gravel sediments on spawning grounds of the Clyde spring herring. Although the deposition of herring spawn resulted in an immediate marked increase in the carbon content of the spawning ground sediments, carbon levels quickly returned to pre-spawning levels and there was no evidence of any permanent or long lasting increase. This held true when the spawn died and decayed in situ and even when it was mixed into the sediment by wave action. The rapid decrease in carbon levels is attributed to the strong water movements which frequently occur over the spawning grounds.


Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1871 ◽  
Author(s):  
Porntip Puttaso ◽  
Weravart Namanusart ◽  
Kanjana Thumanu ◽  
Bhanudacha Kamolmanit ◽  
Alain Brauman ◽  
...  

Leaf litter plays a major role in carbon and nutrient cycling, as well as in fueling food webs. The chemical composition of a leaf may directly and indirectly influence decomposition rates by influencing rates of biological reactions and by influencing the accumulation of soil organic carbon content, respectively. This study aimed to assess the impact of the chemical composition of rubber (Hevea brasiliensis (Willd. ex A. Juss.) Muell. Arg.) leaves on various soil properties of different ages of rubber (4–5, 11–12, and 22–23 year-old). Synchrotron-based Fourier transform infrared microspectroscopy (Sr-FTIR) was utilized for analyzing the chemical composition of plant leaves. The Sr-FTIR bands illustrated that the epidermis of rubber leaves from 4–5-year-old trees was found to contain a high quantity of polysaccharides while mesophyll from 22–23-year-old trees had a large number of polysaccharides. The change in soil properties in the older rubber plantation could be attributed to its chemical composition. The change in soil properties across all tree ages, i.e., increased litter and organic carbon content, was a relatively strong driver of soil biota evolution. The aliphatic of C-H in the leaves showed high correlation with soil organic carbon (SOC) and permanganate-oxidizable C (POXC) from 22–23 year-old trees. This study shows the differences in the organic chemical composition of leaves that are consequential to soil organic carbon.


2012 ◽  
Vol 92 (3) ◽  
pp. 413-418 ◽  
Author(s):  
Thomas E. Fenton

Fenton, T. E. 2012. The impact of erosion on the classification of Mollisols in Iowa. Can. J. Soil Sci. 92: 413–418. The fertile black soils in the Great Plains and Western States of the United States are dark brown Chernozems in the Canadian system of soil taxonomy and Mollisols, when a mollic epipedon is present, according to the United States soil taxonomy. Other primary criteria are organic carbon content, color, structure, and thickness of the mollic epipedon. Accelerated erosion can affect all of these properties and is especially critical for soils that have slope gradients of more than 2%. Accelerated erosion and erosion phases are recognized in field mapping based on the amount of A horizon remaining but criteria provided in the Soil Taxonomy guidelines conflict with procedures outlined in the Soil Survey Field Manual and result in a dichotomy between the classification system and field mapping practices. Soil map unit data for the five most extensive Mollisol soil series in Iowa that have multiple phases of slope and erosion were summarized and variations between the taxonomic and survey principles were identified. Eroded units comprise 26 to 77% of the total mapped area of the series studied and do not qualify as Mollisols under the taxonomic system. However, under the principle of following the genetic thread to classify soils, the taxonomic system should be modified to accommodate the eroded units that have the same genetic pathway as their uneroded counterparts. This could be accomplished by placing primary emphasis on the organic carbon content and waiving the color requirement for eroded soil map units.


2020 ◽  
Vol 31 (5) ◽  
pp. 557-567 ◽  
Author(s):  
Surajit Mondal ◽  
Debashis Chakraborty ◽  
Kalikinkar Bandyopadhyay ◽  
Pramila Aggarwal ◽  
Dharamvir Singh Rana

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaodan Sun ◽  
Gang Wang ◽  
Qingxu Ma ◽  
Jiahui Liao ◽  
Dong Wang ◽  
...  

Abstract Background Soil organic carbon (SOC) is important for soil quality and fertility in forest ecosystems. Labile SOC fractions are sensitive to environmental changes, which reflect the impact of short-term internal and external management measures on the soil carbon pool. Organic mulching (OM) alters the soil environment and promotes plant growth. However, little is known about the responses of SOC fractions in rhizosphere or bulk soil to OM in urban forests and its correlation with carbon composition in plants. Methods A one-year field experiment with four treatments (OM at 0, 5, 10, and 20 cm thicknesses) was conducted in a 15-year-old Ligustrum lucidum plantation. Changes in the SOC fractions in the rhizosphere and bulk soil; the carbon content in the plant fine roots, leaves, and organic mulch; and several soil physicochemical properties were measured. The relationships between SOC fractions and the measured variables were analysed. Results The OM treatments had no significant effect on the SOC fractions, except for the dissolved organic carbon (DOC). OM promoted the movement of SOC to deeper soil because of the increased carbon content in fine roots of subsoil. There were significant correlations between DOC and microbial biomass carbon and SOC and easily oxidised organic carbon. The OM had a greater effect on organic carbon fractions in the bulk soil than in the rhizosphere. The thinnest (5 cm) mulching layers showed the most rapid carbon decomposition over time. The time after OM had the greatest effect on the SOC fractions, followed by soil layer. Conclusions The frequent addition of small amounts of organic mulch increased SOC accumulation in the present study. OM is a potential management model to enhance soil organic matter storage for maintaining urban forest productivity.


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