Activity and abundance of denitrifying bacteria in the subsurface biosphere of diffuse hydrothermal vents of the Juan de Fuca Ridge Biogeosciences DOI 10.5194/bg-9-4661-2012 22 November 2012 Based on our rate measurements, and on published data on hydrothermal fluid fluxes and residence times, we estimated that up to ~10 Tg N yr−1could globally be removed in the subsurface biosphere of hydrothermal vents systems, thus, representing a small fraction of the total marine N loss (~275 to > 400 Tg N yr−1). Read more
Bioerosion by microbial euendoliths in benthic foraminifera from heavy metal-polluted coastal environments of Portovesme (south-western Sardinia, Italy) Biogeosciences DOI 10.5194/bg-9-4607-2012 20 November 2012 We found that carbonate dissolution induced by euendoliths is selective, depending on the Mg content and morpho-structural types of foraminiferal taxa. This study provides evidences for a connection between heavy metal dispersion, decrease in pH of the sea-water and bioerosional processes on foraminifera. Read more
High-resolution interpolar difference of atmospheric methane around the Last Glacial Maximum Biogeosciences DOI 10.5194/bg-9-3961-2012 16 October 2012 Here we present new high-resolution methane records from the North Greenland Ice Core Project and the European Project for Ice Coring in Antarctica Dronning Maud Land ice cores covering Termination 1, the Last Glacial Maximum, and parts of the last glacial back to 32 000 years before present. Read more
Marine bacteria in deep Arctic and Antarctic ice cores: a proxy for evolution in oceans over 300 million generations Biogeosciences DOI 10.5194/bg-9-3799-2012 5 October 2012 Ice cores offer the opportunity to study evolution of marine microbes over ~ 300 million generations by analysing their genomes vs. depth in glacial ice over the last 700 000 yr as frozen proxies for changes in their genomes in oceans. Read more
The carbon budget of terrestrial ecosystems in East Asia over the last two decades Biogeosciences DOI 10.5194/bg-9-3571-2012 7 September 2012 We estimate the current terrestrial carbon balance of East Asia and its driving mechanisms during 1990–2009 using three different approaches: inventories combined with satellite greenness measurements, terrestrial ecosystem carbon cycle models and atmospheric inversion models. Read more
Tree height integrated into pantropical forest biomass estimates Biogeosciences DOI 10.5194/bg-9-3381-2012 27 August 2012 Aboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H). We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer various questions. Read more
A synthesis of carbon in international trade Biogeosciences DOI 10.5194/bg-9-3247-2012 23 August 2012 In a globalised world, the transfer of carbon between regions, either physically or embodied in production, represents a substantial fraction of global carbon emissions. The resulting emission transfers are important for balancing regional carbon budgets and for understanding the drivers of emissions. Read more
Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications Biogeosciences DOI 10.5194/bg-9-3047-2012 10 August 2012 During the August 2009 Mackenzie Light and Carbon (MALINA) Program, the absorbed photon-based efficiency spectra of NH4+photoproduction (i.e. photoammonification) were determined using water samples from the SE Beaufort Sea, including the Mackenzie River estuary, shelf, and Canada Basin. Read more
Detecting anthropogenic carbon dioxide uptake and ocean acidification in the North Atlantic Ocean Biogeosciences DOI 10.5194/bg-9-2509-2012 11 July 2012 Fossil fuel use, cement manufacture and land-use changes are the primary sources of anthropogenic carbon dioxide (CO2) to the atmosphere, with the ocean absorbing approximately 30% (Sabine et al., 2004). Ocean uptake and chemical equilibration of anthropogenic CO2 with seawater results in a gradual reduction in seawater pH and saturation states (Ω) for calcium carbonate (CaCO3) minerals in a process termed ocean acidification. Read more
Bioerosion by euendoliths decreases in phosphate-enriched skeletons of living corals Biogeosciences DOI 10.5194/bg-9-2377-2012 2 July 2012 While the role of microboring organisms, or euendoliths, is relatively well known in dead coral skeletons, their function in live corals remains poorly understood. They are suggested to behave like ectosymbionts or parasites, impacting their host’s health. However, the species composition of microboring communities, their abundance and dynamics in live corals under various environmental conditions have never been explored. Read more
