The aim of the study was to recognise the accumulation of organic carbon (SOC) in the soils of Polish grasslands (GL) and to consider the possibility of increasing its sequestration in these soils. The Tiurin method (mineral soils) and the mass loss method (soil of organic origin) were used. It was found that: (i) the average SOC content of mineral soils is 2.44% and of organic soils – 10.42%; (ii) according to the Polish criteria, approximately 84% of GL mineral soils are classified as classes with high and very high SOC content, and over 15% and 1% – in classes with medium and low SOC content, respectively; more than 99% of organic soils belong to two classes with the highest SOC content and less than 1% to the class with an average content; (iii) according to the European Soil Bureau, the share of GL mineral soils with a high SOC content is slightly over 4%, medium – slightly over 47%, and low and very low – around 50%; for organic soils they are 67, 29, and 4%, respectively; (iv) the reserves of organic carbon in the 0–30 cm layer on the entire surface of GL soils amount to 412.7 Tg of SOC. There is considerable scope for increasing the SOC stock in meadow-pasture soils.

Organic carbon, nitrogen, and phosphorus in the soils of the High Arctic play an important role in the context of global warming, biodiversity, and richness of tundra vegetation. The main aim of the present study was to determine the content and spatial distribution of soil organic carbon (SOC), total nitrogen (N tot ), and total phosphorus (P tot ) in the surface horizons of Arctic soils obtained from the lower part of the Fuglebekken catchment in Spitsbergen as an example of a small non−glaciated catchment representing uplifted marine terraces of the Svalbard Archipelago. The obtained results indicate that surface soil horizons in the Fuglebekken catchment show considerable differences in content of SOC, N tot , and P tot . This mosaic is related to high variability of soil type, local hydrology, vegetation (type and quantity), and especially location of seabird nesting colony. The highest content of SOC, N tot , and P tot occurs in soil surface horizons obtained from sites fertilized by seabird guano and located along streams flowing from the direction of the seabird colony. The content of SOC, N tot , and P tot is strongly negatively correlated with distance from seabird colony indicating a strong influence of the birds on the fertility of the studied soils and indirectly on the accumulation of soil organic matter. The lowest content of SOC, N tot , and P tot occurs in soil surface horizons obtained from the lateral moraine of the Hansbreen glacier and from sites in the close vicinity of the lateral moraine. The content of N tot ,P tot , and SOC in soil surface horizons are strongly and positively correlated with one another, i.e. the higher the content of nutrients, the higher the content of SOC. The spatial distribution of SOC, N tot , and P tot in soils of the Hornsund area in SW Spitsbergen reflects the combined effects of severe climate conditions and periglacial processes. Seabirds play a crucial role in nutrient enrichment in these weakly developed soils.

Water samples were collected at 12 oceanographic stations from six standard depths ranging from 0 to 100 and 150 m. The number of bacteria and concentration of organic components were expressed in adequate units per 1 litre of sea water and in the form of the integrated values for the whole water column under I m2 of sea of organic components were expressed in adequate units per 1 litre of sea water and in the form of the integrated values for the whole water column under 1 m2 of sea surface. Total numbers of bacteria (TC) ranged from 0.16 to 7.31 x 107/1 and 1.74 — 5.67 x 10, 2/m2 saprophytic bacteria (CFU) 0.10 — 46.85 x 103/1 and 0.62 — 27.7x 108/m2. contents of particulate organic carbon (РОС) 0.02 — 0.25 mg/1 and 3.5 — 20.0 g/m2 dissolved organic carbon (DOC) 0.07 — 3.02 mg/1 and 53.5 — 207.9 g/m2, dissolved free amino acids (DFAA) 0 — 1.8965 μmol/1 and 2.7 -151.5 mmol/m2, dissolved combined amino acids (DCAA) 0 2.9366 μmо1/1 and 16.5— 163.5 mmol/m2, particulate combined amino acids (PCAA) 0 — 3.0215 μmо1/1 and 3.7 — 249.0 mmol/m2. Total numbers of bacteria and РОС, DOC and DCAA concentrations, widely differentiated in the investigated area, were on the average much lower than the values obtaine in previous years. The saprophytic bacteria content and DFAA and PCAA concentrations were at a similar level to that in the past years. Higher TC and CFU values were observed in the areas with high concentrations of phytoioplankton to the NW of Anvers I. and around Clarence I.

This study presents the spatial variability and dynamics of soil organic carbon (SOC), soil organic matter (SOM) and soil pH contents at the Wonji Shoa Sugar Estate (WSSE), Ethiopia. Soil samples were collected immediately after the sug-arcane was harvested and then analysed for SOC, SOM and pH content using standard procedures. The analysis resultsshowed that the pH value varied between 6.7–8.4 (neutral to moderately alkaline) and 7.3–8.5 (neutral to strongly alkaline) for the top and bottom soil profiles, respectively. The SOM content is in the range of 1.1–6.7% and 0.74–3.3% for the upper and lower soil layers, respectively. Nearly 45% of the samples demonstrated a SOM content below the desirable threshold (<2.1%) in the bottom layer and, hence, inadequate. Moreover, most of the topsoil layer (95%) has an SOM content exceed-ing the desirable limit and hence is categorized within the normal range. Interestingly, the SOC content showed a spatial variability in both the surface and sub-surface soil layers. A lower SOC and SOM content was found for the sub-soil in the south and southwestern part of the plantation. A further decline in the SOC and SOM content may face the estate if the cur-rent waterlogging condition continues in the future for a long period. Overall, the study result emphasizes the need to min-imize the pre-harvest burning of sugarcane and action is needed to change the irrigation method to green harvesting to fa-cilitate the SOC retention in the soil and minimize the greenhouse emission effect on the environment, hence improving soil quality in the long-term.

The Passhatten Member (Anisian–Ladinian) is the most westward exposure of the Middle Triassic sedimentary sequence of Spitsbergen. The member has an average organic carbon of 2.21 wt %. The sediments were deposited in a shallow shelf environment under conditions of high biological productivity stimulated by a well−developed upwelling system and an enhanced nutrient supply from land areas. The high biological productivity caused a high supply of organic particles to the shelf bottom. Decomposition of organic matter initiated oxygen deficiency in the bottom waters; however, bottom water dynamics on the shallow shelf temporarily replenished the oxygen. Consequently, the Passhatten Mb section is bioturbated, even in thick black shale horizons and consists of alternately spaced lithological layers with variable organic carbon content. The organic matter is dominated by type II kerogen with a mixture of strongly altered marine and/or land derived organic matter. Calculated initial hydrogen index values suggest oil−prone organic matter similar to kerogen I and II types. The organic matter is in the upper intermediate stage of thermo−catalytic alteration, close to the cata− and metagenetic boundary. Maturity indicators including Rock−Eval, Maximum Temperature, Organic Matter Transformation Ratio, Residual Carbon content, as well as the volume of methane generated suggest mature to overmature organic matter. Methane potential retained in the black shales sequence is significant. Unexpelled gas is estimated at 395 mcf/ac−ft for the examined section.

A sediment core (LS-1) collected from Long Lake in King George Island, South Shetland Islands (West Antarctica) was analyzed for a variety of textural, geochemical, isotopic and paleontological properties together with 14C age dates. These data combined with published records of other studies provide a detailed history of local/regional postglacial paleoproductivity variation with respect to terrestrial paleoclimate change. The lithologic contrast of a lower diamicton and an upper fine-grained sediment demonstrates glacial recession and subsequent lake formation. The upper fine-grained deposit, intercalated by mid-Holocene tephra-fallout followed by a tephra gravity flow, was formed in a lacustrine environment. Low total organic carbon (TOC) and biogenic silica (Sibio) contents with high C/N ratios characterize the diamicton, whereas an increase of TOC and Sibio contents characterize the postglacial lacustrine fine-grained sediments, which are dated at c. 4000 yrBP. More notable are the distinct TOC maxima, which may imply enhanced primary productivity during warm periods. Changes in Sibio content and δ13C values, which support the increasing paleoproductivity, are in sympathy with these organic matter variations. The uniform and low TOC contents that are decoupled by Sibio contents are attributed to the tephra gravity flows during the evolution of the lake rather than a reduced paleoproductivity. A very recent TOC maximum is also characterized by high Sibio content and δ13C values, clearly indicating increased paleoproductivity consequent upon gradual warming across King George Island . Comparable with changes in sediment geochemistry, the occurrence and abundance of several diatom species corroborate the paleoproductivity variations together with the lithologic development. However, the paleoclimatic signature in local terrestrial lake environment during the postglacial period (for example the Long Lake) seems to be less distinct, as compared to the marine environment.

51 samples from the Middle Triassic black shales (organic carbon−rich silt− stones; up to 4.9% TOC – Total Organic Carbon) from the stratotype section of the Bravaisberget Formation (western Spitsbergen) were analyzed with respect to isotopic composition of pyritic sulphur (δ34S) and TOC. Isotopic composition of syngenetic py− rite−bound sulphur shows wide (δ34S from −26‰ to +8‰ VCDT) and narrow (δ34S from −4‰ to +17‰ VCDT) variation of the δ34S in upper and lower part of the section, respec− tively. Range of the variation is associated with abrupt changes in dominant lithology. Wide δ34S variation is found in lithological intervals characterized by alternation of black shales and phosphorite−bearing sandstones. The narrow δ34S variation is associated with the lithological interval dominated by black shales only. Wide and narrow variation of the δ34S values suggests interplay of various factors in sedimentary environment. These fac− tors include oxygen concentration, clastic sedimentation rate, bottom currents and bur− rowing activity. Biological productivity and rate of dissimilatory sulphate reduction had important impact on the δ34S variation as well. Wide variation of the δ34S values in the studied section resulted from high biological productivity and high rate of dissimilatory sulphate reduction. Variable degree of clastic sedimentation rate and burrowing activity as well as the activity of poorly oxygenated bottom currents could also cause a co−occurrence of isotopically light and heavy pyrite in differentiated diagenetic micro−environments. Occurrence of organic matter depleted in hydrogen could also result in a wide variation of the δ34S values. Narrow variation of the δ34S values was due to a decrease of biological productivity and low rate of dissimilatory sulphate reduction. Low organic matter supply, low oxygen concentration and bottom currents and burrowing activity were also responsible for narrow variation of the δ34S. The narrow range of the δ34S variation was also due to occurrence of hydrogen−rich organic matter. In the studied section the major change in range of the δ34S variation from wide to narrow appears to be abrupt and clearly associated with change in lithology. The change of lithology and isotopic valuesmay sug− gest evolution of the sedimentary environment from high− to low−energy and also facies succession from shallow to deeper shelf. The evolution should be linked with the Late Anisian regional transgressive pulse in the Boreal Ocean.

Experiments have been carried out on the influence exerted by Aroclor 1254 upon the photosynthetic production of organic 14C by an assemblage of marine Antarctic diatoms (Thalassiosira sp. 48%, Nitzschia sp. 21%, Chaetoceros sp. 15% and Corethron iriophilum 10%). Samples of various numbers of cells per cm3 of water have been used. Incorporation of 14C02 by the diatoms proved to be proportional to the increased number of cells in the sample only at the lowest levels of concentration in per cm3. Further increase of the level of 14C in diatoms has not been found as number of cells in the sample kept growing. Calculation of brutto photosynthesis has indicated that low concentration of Aroclor 1254 (0,01 to 1 ppm) may stimulate the photosynthetic incorporation of carbon, yet the photosynthetic release of carbon from cells within the photorespiratory process is stimulated to a higher degree. High concentration of Aroclor (1 to 50 ppm) inhibit the brutto assimilation, yet the release of carbon during the photorespiratory process is inhibited to a higher degree. A hypothesis is being considered implying that the relation between the intensity of photosynthesis and intensity of photorespiration may vary according to the rate of concentration of Aroclor.

The study analysed the relationship between the granulometric composition of grassland soils as determined by laser diffraction and their content of mineral forms of nitrogen and organic carbon. The content of mineral forms of nitrogen (NO _3-N and NH _4-N) in soil samples – after their extraction with 1% solution K ₂SO ₄, was determined by flow colourimetry. Soil organic carbon content was determined using the Tyurin method. The study examined soil samples collected from 169 control and measurement sites located in different regions of Poland in terms of conditions for agricultural production. Statistical analyses of the research results showed that the grain size of grassland soils had a significant effect on their ammonium nitrogen content but not on their nitrate nitrogen and organic carbon content. In this respect, it was found that there was a positive correlation between the share of the sand fraction and the content of ammonium nitrogen in soils and an opposite relation between the share of coarse silt, fine silt and clay and the content of the aforementioned component. Results of the analyses differ considerably from the results of studies by other authors on the influence of soil grain size distribution on the content of mineral nitrogen and organic carbon in soils based on classical methods of measurements of soil particle size distribution. There is a need to develop solutions to convert and compare results obtained by laser diffraction and standard methods.

Seabirds constitute an important link between marine and terrestrial ecosystems, one of its manifestations being the transport of organic matter from the sea to breeding grounds. The main aim of our study was to determine the impact of gregarious and planktivorous little auks on the quantity and chemistry of soil organic matter along the western coast of Spitsbergen, Svalbard archipelago. Samples from the vicinity of four breeding colonies and respective controls were investigated using the elemental analyzers as well as the Fourier transform infrared spectrometer with attenuated total reflection module. The results clearly indicate that soils affected by little auks are characterized by significantly higher content of soil organic carbon, total nitrogen, water-extractable organic carbon, and water-extractable total nitrogen in comparison with those unaffected by the birds. The size of the local population of little auks appears to be the crucial factor here. The chemistry of soil organic matter in soils affected by little auks is significantly different from that in soils unaffected by the birds. This is associated with fertilization of soils via guano deposition as well as differences in the quantity and quality of vegetation cover related to aforementioned process.