Stable isotope studies of moss sulfur and sulfate from bog surface waters

Abstract

Two moss genera (Sphagnum and Polytrichum) were collected seasonally in two close (~0.45 km distance) but environmentally different locations, an Open bog and a Spruce forest at Hala Izerska (the Izerskie Mts./SW Poland), for the stable isotope analyses of plant in-body sulfur. Simultaneously, surface water was collected in places of moss growth and along the creek discharging the bog, for stable isotope analysis of sulfate sulfur (5 locations/5 times in growing seasons). The δ 34 S value of the analyzed mosses varies from 3.99 to 10.24‰ for Sphagnum and from 4.18 to 6.48‰ for Polytrichum. The δ 34 S value of aqueous sulfate in creek waters, depending on location and season, ranges from 3.72 to 20.26‰. The significant correlation between the plant in-body sulfur concentration and the isotopic composition was observed for Sphagnum as well as loose correlation between δ 34 S of sulfates in surface water and moss in-body sulfur. The fractionation factor, possibly caused by two processes of sulfate assimilation by Sphagnum and sulfate reduction by bacteria, calculated based on Rayleigh's distillation model equals about 4‰. The high correlation and simultaneous increase of δ 34 S(SO 4 2-) and δ 13 C(DIC) values downstream the creek discharging the bog suggest that the lighter isotopes of carbon and sulfur ( 12 C and 32 S) are preferentially removed, probably due to assimilation by plants. The present results imply the original signature of the source of sulfur in the environment is greatly altered by the biological activities in bog water.

Identification of Sulfate Sources and Biogeochemical Processes in an Aquifer Affected by Peatland: Insights from Monitoring the Isotopic Composition of Groundwater Sulfate in Kampinos National Park, Poland

“…A large proportion of the sulfates in the studied aquifer might originate from the decomposition of peat during times of low water table. Similar trends were observed in [45,46]. Sulfur compounds may be retained in the peat as both (i) organic forms and (ii) reduced inorganic forms (RIS), depending on the oxygen availability [4].…”

“…Rainfall facilitates the dissolution of sulfates (e.g., gypsum) and their transfer to the aquifer. During times of high groundwater level caused by heavy rains in autumn and snow thawing in spring, a peat layer occurs within the saturation zone, and a considerable admixture of additional sulfates with an atmospheric origin or related to gypsum dissolution or dissolution (oxidation) or RIS compounds can reach groundwater, increasing the sulfate concentration in the water in the aquifer below the peat layer [44][45][46]. At a depth of 3.3 m, the y-axis intercept yielded a δ 34 S I value of −7.9% , the same as the average for all water samples ( Figure 5B).…”

Sulfur isotopes in coal constrain the evolution of the Phanerozoic sulfur cycle

“…In many modern peats, rainwater is often cited as a major source of sulfate to the plants forming the peat (e.g., refs. 21,25,31). This view, however, is heavily biased by the large fluxes of anthropogenic sulfur to the atmosphere from multiple vectors including biomass burning and fossil fuel combustion.…”

“…Due to this limitation, the peats have low organic sulfur contents (0.32 ± 0.09 wt % S) with δ 34 S values similar to the plants forming the peats and the surface waters in the swamp (18,19). Furthermore, in a study of moss and underlying peats from the Karkonosze Mountains in Southwestern Poland (20), the isotope signal from the moss was transferred to the underlying peat (within about 2 per mil), and in the peat bog "Nad Jagniecym Potokiem" in the Izerska Mountains in Southwest Poland, the δ 34 S of Sphagnum and Polytrichum mosses were consistently within 2-3 per mil of the surface water sulfate source (21). In a comprehensive study of Sphagnum moss from a variety of spruce forest floors in Europe, the δ 34 S of the plant sulfur resembled that of the source sulfate, but with a consistent 2 per mil shift to 34 S-depleted values during assimilation (22).…”

δ 34 S values and S concentrations in native and transplanted Pleurozium schreberi in a heavily industrialised area

“…In the laboratory 10 g of wet moss mass was separated. The moss was washed briefly twice with redistilled water (Gałuszka, 2005;Skrzypek et al, 2008) to remove loosely attached dust and soluble sulphur forms deposited on the plant surface. Subsequently, the moss samples were vacuum-dried (freeze-dried in a Labogene ApS CoolSafe 55-4 lyophilizer, Denmark) and weighed.…”