Effect of floods on the δ13C values in plant leaves: a study of willows in Northeastern Siberia

Different survival strategies involve carbon translocation rather than de novo C assimilation under complete submergence in rice plant

This study investigated the effect of transient submergence on the recovery of photosynthetic activity and translocation of photosynthate in IR67520 (Sub1A genotype) and IR72442 (non-Sub1A genotype) using ¹³C-labeled tracer, coupled with some photosynthetic physiological assessments. Plant growth, photosynthetic capacity, and photosynthetic recovery were studied by treating the two rice genotypes without or completely submerged for 7 days in transparent acrylic tanks filled with water to a depth of 80 cm, followed by 7 days of reaeration. Results revealed that the IR67520 was able to obtain new carbon source for assimilation during at 7 days of recovery periods. The IR72442 genotype partitioned ¹³C to the newly developed upper leaves more than the IR67520 genotype did. This was due to its inability to obtain CO₂ from other source during post submergence. Recovery of chlorophyll content, ability to retain higher biomass, and ability to grow faster at 7 days of recovery periods also indicated the ability of Sub1A genotype to reactivate its photosynthetic capacity.

Of herds and societies-Seasonal aspects of Vinča culture herding and land use practices revealed using sequential stable isotope analysis of animal teeth

Late Neolithic Vinča communities, spread over much of central and northern Balkans during the late sixth to mid-fifth millennium BC and characterised by unusually large and densely population centres, would have required highly organised food production systems. Zooarchaeological analysis indicates that domesticate livestock were herded, but little is known about the seasonal husbandry practices that helped ensure a steady supply of animal products to Vinča farming communities. Here, we present new stable carbon (δ13C) and oxygen (δ18O) isotopic measurements of incremental bioapatite samples from the teeth of domesticated livestock and wild herbivore teeth from two late Neolithic Vinča culture sites: Vinča-Belo brdo and Stubline (Serbia). Our results show a low variation overall within sheep and goats in terms of pasture type that may have been composed of seasonal halophyte plant communities, which have higher δ13C values due to the saline rich growing environments. Cattle feeding strategies were more variable and provided with supplementary forage, such as cut branches or leafy hay, during winter. The sharp distinction in the management of cattle and sheep/goat may be associated with the development of herding strategies that sought to balance livestock feeding behaviours with available forage or, more provocatively, the emergence of household-based control over cattle-an animal that held a central economic and symbolic role in Vinča societies.

Isotopic compositions of ground ice in near-surface permafrost in relation to vegetation and microtopography at the Taiga-Tundra boundary in the Indigirka River lowlands, northeastern Siberia

The warming trend in the Arctic region is expected to cause drastic changes including permafrost degradation and vegetation shifts. We investigated the spatial distribution of ice content and stable isotopic compositions of water in near-surface permafrost down to a depth of 1 m in the Indigirka River lowlands of northeastern Siberia to examine how the permafrost conditions control vegetation and microtopography in the Taiga–Tundra boundary ecosystem. The gravimetric water content (GWC) in the frozen soil layer was significantly higher at microtopographically high elevations with growing larch trees (i.e., tree mounds) than at low elevations with wetland vegetation (i.e., wet areas). The observed ground ice (ice-rich layer) with a high GWC in the tree mounds suggests that the relatively elevated microtopography of the land surface, which was formed by frost heave, strongly affects the survival of larch trees. The isotopic composition of the ground ice indicated that equilibrium isotopic fractionation occurred during ice segregation at the tree mounds, which implies that the ice formed with sufficient time for the migration of unfrozen soil water to the freezing front. In contrast, the isotopic data for the wet areas indicated that rapid freezing occurred under relatively non-equilibrium conditions, implying that there was insufficient time for ice segregation to occur. The freezing rate of the tree mounds was slower than that of the wet areas due to the difference of such as soil moisture and snow cover depends on vegetation and microtopography. These results indicate that future changes in snow cover, soil moisture, and organic layer, which control underground thermal conductivity, will have significant impacts on the freezing environment of the ground ice at the Taiga–Tundra boundary in northeastern Siberia. Such changes in the freezing environment will then affect vegetation due to changes in the microtopography of the ground surface.