Issues Related to Incorporating Northern Peatlands into Global Climate Models

Northern peatlands cover ~3–4 million km2 (~10% of the land north of 45°N) and contain ~200–400 Pg carbon (~10–20% of total global soil carbon), almost entirely as peat (organic soil). Recent developments in global climate models have included incorporation of the terrestrial carbon cycle and representation of several terrestrial ecosystem types and processes in their land surface modules. Peatlands share many general properties with upland, mineral-soil ecosystems, and general ecosystem carbon, water, and energy cycle functions (productivity, decomposition, water infiltration, evapotranspiration, runoff, latent, sensible, and ground heat fluxes). However, northern peatlands also have several unique characteristics that will require some rethinking or revising of land surface algorithms in global climate models. Here we review some of these characteristics, deep organic soils, a significant fraction of bryophyte vegetation, shallow water tables, spatial heterogeneity, anaerobic biogeochemistry, and disturbance regimes, in the context of incorporating them into global climate models. With the incorporation of peatlands, global climate models will be able to simulate the fate of northern peatland carbon under climate change, and estimate the magnitude and strength of any climate system feedbacks associated with the dynamics of this large carbon pool

Potential for Abrupt Changes in Atmospheric Methane

Methane (CH4) is the second most important greenhouse gas that humans directly influence, carbon dioxide (CO2) being first. Concerns about methane’s role in abrupt climate change stem primarily from (1) the large quantities of methane stored as solid methane hydrate on the sea floor and to a lesser degree in terrestrial sediments, and the possibility that these reservoirs could become unstable in the face of future global warming, and (2) the possibility of large-scale conversion of frozen soil in the high- latitude Northern Hemisphere to methane producing wetland, due to accelerated warming at high latitudes. This chapter summarizes the current state of knowledge about these reservoirs and their potential for forcing abrupt climate change

The syntheses of methyl jasmonate and analogs of alpha-methylene-gamma-butyrolactone utilizing titanium medicated cyclocarbonylation

From its humble beginnings as a novel carbon–carbon bond forming reaction, the Pauson–Khand reaction has lead to the synthetic development of a variety of natural products. One particular variation of the Pauson–Khand reaction was called the hetero Pauson–Khand. This reaction differs from the normal Pauson–Khand reaction because the reaction employs an intramolecular titanium mediated cycloaddition using enal and enones instead of alkenes and alkynes functional groups to prepare a variety of natural products. These natural products usually contain a bicyclic cyclopentenone core. Because the new ring contains a hetero atom, the name hetero Pauson–Khand was coined. Alpha–Methylene–Gamma–Butyrolactones posses a wide range of biological activities. These activities range from antibacterial to anti–inflammatory and make these lactones interesting targets for synthetic groups to produce in labs. In an attempt to expand our knowledge of titanium chemistry, alpha–methylene–gamma–butyrolactones syntheses were investigated using titanium catalyzed hetero Pauson–Khand reaction. Several substituted titanacene metallacycles were produced in good to excellent yields since the carbon monoxide insertion under pressure proved problematic. Because of its importance to the perfume industry; many synthetic groups have synthesized methyl jasmonate. Methyl jasmonate was synthesized from 3–(tert–Butyl–dimethyl–silanyloxy)–propionaldehyde and 5–Bromo–penta–1,3–diene using the hetero Pauson–Khand reaction in twelve steps. Methyl jasmonate was converted from jasmonic acid in 60 % yield as clear oil. In an effort to circumvent the problems associated with synthesizing alpha–methylene–gamma–butyrolactones from the hetero Pauson–Khand reaction; isonitrile insertions into allenals and allenones were investigated. If successful, these iminocyclopentanones would have been hydrolyzed to the corresponding alpha–methylene–gamma–butyrolactones. Initial titanacene macrocycles formed, but the desired iminocyclopentanones intermediates were never produced

GABA-B controls persistent Na+ current and coupled Na+-activated K+ current

AbstractThe GABA-B receptor is densely expressed throughout the brain and has been implicated in many CNS functions and disorders, including addiction, epilepsy, spasticity, schizophrenia, anxiety, cognitive deficits, and depression, as well as various aspects of nervous system development. How one GABA-B receptor is involved in so many aspects of CNS function remains unanswered. Activation of GABA-B receptors is normally thought to produce inhibitory responses in the nervous system, but puzzling contradictory responses exist. Here we report that in rat mitral cells of the olfactory bulb, GABA-B receptor activation inhibits both the persistent sodium current (INaP) and the sodium-activated potassium current (IKNa), which is coupled to it. We find that the primary effect of GABA-B activation is to inhibit INaP, which has the secondary effect of inhibiting IKNabecause of its dependence on persistent sodium entry for activation. This can have either a net excitatory or inhibitory effect depending on the balance of INaP/IKNacurrents in neurons. In the olfactory bulb, the cell bodies of mitral cells are densely packed with sodium-activated potassium channels. These channels produce a large IKNawhich, if constitutively active, would shunt any synaptic potentials traversing the soma before reaching the spike initiation zone. However, GABA-B receptor activation might have the net effect of reducing the IKNablocking effect, thus enhancing the effectiveness of synaptic potentials.</jats:p

The first-order effect of Holocene Northern Peatlands on global carbon cycle dynamics

Given the fact that the estimated present-day carbon storage of Northern Peatlands (NP) is about 300–500 petagram (PgC, 1 petagram = 1015 gram), and the NP has been subject to a slow but persistent growth over the Holocene epoch, it is desirable to include the NP in studies of Holocene carbon cycle dynamics. Here we use an Earth system Model of Intermediate Complexity to study the first-order effect of NP on global carbon cycle dynamics in the Holocene. We prescribe the reconstructed NP growth based on data obtained from numerous sites (located in Western Siberia, North America, and Finland) where peat accumulation records have been developed. Using an inverse method, we demonstrate that the long-term debates over potential source and/or sink of terrestrial ecosystem in the Holocene are clarified by using an inverse method, and our results suggest that the primary carbon source for the changes (sinks) of atmospheric and terrestrial carbon is the ocean, presumably, due to the deep ocean sedimentation pump (the so-called alkalinity pump). Our paper here complements ref. 1 by sensitivity tests using modified boundary conditions

The association between playgroup participation, learning competency and social-emotional wellbeing for children aged four-five years in Australia

Data from Growing Up in Australia: The Longitudinal Study of Australian Children is used to examine the associations between playgroup participation and the outcomes for children aged 4 to 5 years. Controlling for a range of socio-economic and family characteristics, playgroup participation across the ages of 0-3 years was used to predict learning competence and social-emotional functioning outcomes at age 4-5 years. For learning competence, both boys and girls from disadvantaged families scored 3-4% higher if they attended playgroup when aged 0-1 and 2-3 years compared to boys and girls from disadvantaged families who did not attend playgroup. For social and emotional functioning, girls from disadvantaged families who attended playgroup when they were aged 0-1 and 2-3 years scored nearly 5% higher than those who did not attend. Demographic characteristics also showed that disadvantaged families were the families least likely to access these services. Despite data limitations, this study provides evidence that continued participation in playgroups is associated with better outcomes for children from disadvantaged families