Impact of non-outbreak insect damage on vegetation in northern Europe will be greater than expected during a changing climate

Background insect herbivory, in addition to insect outbreaks, can have an important long term influence on the performance of tree species. Since a projected warmer climate may favour insect herbivores, we use a dynamic ecosystem model to investigate the impacts of background herbivory on vegetation growth and productivity, as well as distribution and associated changes in terrestrial ecosystems of northern Europe. We used the GUESS ecosystem modelling framework and a simple linear model for including the leaf area loss of Betula pubescens in relation to mean July temperature. We tested the sensitivity of the responses of the simulated ecosystems to different, but realistic, degrees of insect damage. Predicted temperature increases are likely to enhance the potential insect impacts on vegetation. The impacts are strongest in the eastern areas, where potential insect damage to B. pubescens can increase by 4–5%. The increase in insect damage to B. pubescens results in a reduction of total birch leaf area (LAI), total birch biomass and birch productivity (Net Primary Production). This effect is stronger than the insect damage to leaf area alone would suggest, due to its second order effect on the competition between tree species. The model's demonstration that background herbivory may cause changes in vegetation structure suggests that insect damage, generally neglected by vegetation models, can change predictions of future forest composition. Carbon fluxes and albedo are only slightly influenced by background insect herbivory, indicating that background insect damage is of minor importance for estimating the feedback of terrestrial ecosystems to climate change.     

Late archean komatiites and global features of their ore potential

Doklady Earth Sciences -     

New Data on the Age of Neoproterozoic Volcanic Rocks of the Isakovka Terrane,Sayan–Yenisei Accretion Belt (U–Pb,Zircon)

Doklady Earth Sciences - A Late Neoproterozoic U–Pb zircon age is established for the first time for arc metadacites (691 ± 8.8 Ma) and basalts (572 ± 6.5 Ma) from the...     

A Linear Dynamic Model for Calculating the Transverse Oscillation of Free-Floating Ice Cover

A linear dynamic model is developed for evaluating the parameters of the mode of deformation of ice cover under the effect of an under-ice current and free-flowing water mass on the upper ice surface. An analytical solution describing the flexure of ice slab in the water–ice system is derived.     

Decline in Length of the Summer Season on the Kola Peninsula, Russia

By analysing records made in the northern taiga forests of the Lapland Reserve (Kola Peninsula, Russia) during 1930–1998, we unexpectedly discovered a decline in the length of the snow-free and ice-free periods by 15–20 days due to both delayed spring and advanced autumn/winter. Respective seasonal temperatures best explained the dates of all phenological phases: 1 °C shift in temperature was approximately equal to 2–5 day shift in phenology. However the phenological shiftsduring the observation period are much larger than could be expected from the slight (0.56 °C) drop in temperatures during August–September, suggesting that the biotic effects of a very slight cooling have been enhanced by one or more unknown factors. Although emissions of sulphur dioxide from the nickel-copper smelter at Monchegorsk may have contributed to the observed trend (via changes in regional radiative budget), we found no evidence of direct pollution impact on dates of birch autumnal coloration or birch leaf fall, which exhibited the largest (22 days) shift between 1930 and 1998. The detected phenological trends agree with an increase in winter (snow) precipitation in the study area by 44%; however, effects of precipitation on any of the investigated phenological phases were far from significant. Our results highlight the importance of phenological records for the assessment of past regional environmental changes, and demonstrates that the prediction of even the simplest biotic responses to the Global Changes requires a profound understanding of the interactive impact of abiotic factors on the ecosystem.     

Genesis of ringwoodite during metamorphism induced by impact waves: Experimental data

Ringwoodite, a high-density olivine modification, was first synthesized by loading plagioclase-biotite-quartz schist containing garnet and staurolite by impact waves. Ringwoodite was identified in the impact-thermal aggregates that replaced biotite (together with a mineral corresponding to spinel in chemical composition and with a biotite residue). The physical parameters under which ringwoodite was synthesized in this experiment (P _imp ～ 20–30 GPa and T ～ 1060–1500°C) include a pressure approximately 1.5 times higher than that in static analogous experiments. The ringwoodite was formed via the regrouping of and the associated removal and addition of material, as follows from the development of ringwoodite after biotite, a mineral of principally different composition. Component migration was reliably confirmed by the microprobe mapping of the chemistries of the original and newly formed minerals, which makes the origin of the ringwoodite similar to the origin of diamond (togorite) in the Kara astrobleme, where the impact loading was up to ten times higher than the static pressure.     

C-and Sr-isotope chemostratigraphy as a tool for verifying age of Riphean deposits in the Kama-Belaya aulacogen,the east European platform

The Kyrpy Group of the East European platform is regarded by tradition as correlative with the Lower Riphean Burzyan Group of the Bashkirian meganticlinorium in the southern Urals. Age and correlation of the Kyrpy Group remain problematic, however, because of a limited geochronological information and controversial interpretation of paleontological materials. Data of C-and Sr-isotope chemostratigraphy contribute much to the problem solution. In the Kyrpy Group of the Kama-Belaya aulacogen, the Kaltasy Formation carbonates 1300 to 2400 m thick (boreholes 133 and 203 of the Azino-Pal’nikovo and Bedryazh areas) show ⁸⁷Sr/⁸⁶Sr ratios ranging around 0.7040 and narrow diapasons of δ¹³C values: about 0.5‰ (V-PDB) in shallow-water facies and-2.0‰ (V-PDB) in sediments of deeper origin. Despite the facies dependence of carbon isotope composition, δ¹³C variations not greater than ±1.0‰ are depicted in chemostratigraphic profiles of carbonate rocks characterizing separate stratigraphic intervals up to 800 m thick in the above borehole sections. Low ⁸⁷Sr/⁸⁶Sr ratios and almost invariant δ¹³C values in carbonates of the Kaltasy Formation are obviously contrasting with these parameters in the Middle and Upper Riphean deposits, being comparable with isotopic characteristics of the Lower Riphean sediments (Mesoproterozoic deposits older than 1300 Ma). Consequently, the results obtained evidence in favor of the Early Riphean age of the Kaltasy Formation and the Kyrpy Group as a whole.     

Geochemistry,Formation Settings,and Ore Potential of the Volcano-Sedimentary Complexes of Pryangarya,Yenisei Ridge

Doklady Earth Sciences - In the Angara part of the Yenisei Ridge, a sequential section of the metapicrite–basalt sequence and the overlying carbonate rocks of the Gorevskaya suite has been...     

Characteristics of short-period internal waves in the Kara Sea inferred from satellite SAR data

In this paper we present the results of short-period internal wave (SIW) observations in the Kara Sea on the basis of satellite ENVISAT ASAR data between July and October 2007. Altogether, 248 internal wave (IW) packets and solitons are identified in 89 SAR images. Detailed spatial statistics of IW signatures and their properties in the Kara Sea is presented. The primary regions of IW activity are the areas near the Kara Gates Strait, the southeastern part of the Novaya Zemlya Trough, and in the vicinity of Cape Zhelaniya. We identify the regions where large IW packets are observed with wavelengths up to 2–3 km and the front length exceeding 200 km. The mean interpacket distance for observed IWs is about 20 km, but it may reach 50–60 km. Consequent IW packets are observed to travel up to 500 km from the presumed generation points. The results of satellite observations are compared with results of previous studies.