Are benthic fluxes important for the availability of Si in the Gulf of Finland?

We estimated the efflux of dissolved silicon (DSi) from sediments in the Gulf of Finland and compared it to sedimentation fluxes, burial of Si and existing data on Si loading and stocks, reassessing the reliability of existing Si budgets. Benthic fluxes of DSi measured in situ and in vitro were several times higher than estimates from diffusion calculations. The spatial variability in the open Gulf of Finland was relatively small, while both very high and low fluxes were measured from coastal areas. Fluxes were highest in late summer and lowest in early spring. In our re-assessed budget we present a new lower estimate for Si burial in the sediments, ca. 6 Gmol a(-1) and show that more than half of the sedimentation flux of Si is released back into the water column. Changes in the efficiency of internal DSi recycling may thus affect the prevalence of siliceous phytoplankton within the ecosystem, and the diatom spring bloom may be regulated by the functioning of this internal recycling pump. We also show that the seasonal variation in benthic DSi fluxes and dissolved phosphate fluxes is similar, and that a tentative connection between hypoLxia and high DSi efflux exists. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe

Towards a more comprehensive understanding of lacustrine greenhouse gas dynamics — two-year measurements of concentrations and fluxes of CO2, CH4 and N2O in a typical boreal lake surrounded by managed forests

Peer reviewe

Methane and carbon dioxide fluxes over a lake : comparison between eddy covariance, floating chambers and boundary layer method

Freshwaters bring a notable contribution to the global carbon budget by emitting both carbon dioxide (CO2) and methane (CH4) to the atmosphere. Global estimates of freshwater emissions traditionally use a wind-speed-based gas transfer velocity, k CC (introduced by Cole and Caraco, 1998), for calculating diffusive flux with the boundary layer method (BLM). We compared CH4 and CO2 fluxes from BLM with k CC and two other gas transfer velocities (k TE and k HE), which include the effects of water-side cooling to the gas transfer besides shear-induced turbulence, with simultaneous eddy covariance (EC) and floating chamber (FC) fluxes during a 16-day measurement campaign in September 2014 at Lake Kuivajarvi in Finland. The measurements included both lake stratification and water column mixing periods. Results show that BLM fluxes were mainly lower than EC, with the more recent model k TE giving the best fit with EC fluxes, whereas FC measurements resulted in higher fluxes than simultaneous EC measurements. We highly recommend using up-to-date gas transfer models, instead of kCC, for better flux estimates. BLM CO2 flux measurements had clear differences between daytime and night-time fluxes with all gas transfer models during both stratified and mixing periods, whereas EC measurements did not show a diurnal behaviour in CO2 flux. CH4 flux had higher values in daytime than night-time during lake mixing period according to EC measurements, with highest fluxes detected just before sunset. In addition, we found clear differences in daytime and night-time concentration difference between the air and surface water for both CH4 and CO2. This might lead to biased flux estimates, if only daytime values are used in BLM upscaling and flux measurements in general. FC measurements did not detect spatial variation in either CH4 or CO2 flux over Lake Kuivajarvi. EC measurements, on the other hand, did not show any spatial variation in CH4 fluxes but did show a clear difference between CO2 fluxes from shallower and deeper areas. We highlight that while all flux measurement methods have their pros and cons, it is important to carefully think about the chosen method and measurement interval, as well as their effects on the resulting flux.Peer reviewe

Effects of cooling and internal wave motions on gas transfer coefficients in a boreal lake

Peer reviewe

The group on earth observations carbon and greenhouse gas initiative

An improved understanding of the global carbon cycle is important to the success of efforts to mitigate climate change, such as agreed in the Paris meeting of the UN Conference of the Parties in 2016. Climate change mitigation and adaptation requires action by individual countries, municipalities, cities, and their citizens. These actions require a diverse range of information. Current efforts responding to the need for these carbon observations are, however, fragmented. There is a need to coordinate observations on carbon, GHG measurements, and ecosystem processes related to carbon cycle dynamics. The GEO Carbon and Greenhouse Gas Initiative (GEO-C) was launched to further support continuity and coherence of the ongoing efforts and facilitate their cooperation and interoperability. The GEO-C Initiative (1) supports the development of a holistic cross-domain, global carbon cycle and GHG monitoring system that provides long-term, high quality, and open access; (2) engages with users and policy makers and ensures the fitness for purpose of the observation and reporting system; and (3) aims to establish a common terminology (including scientists and decision makers) involved in addressing GHG emissions. This chapter describes the background of the GEO-GHG initiative and describes the main aims of the initiative and first steps toward implementation

RVD induction and autologous stem cell transplantation followed by lenalidomide maintenance in newly diagnosed multiple myeloma:a phase 2 study of the Finnish Myeloma Group

Abstract Autologous stem cell transplantation (ASCT) combined with novel agents is the standard treatment for transplant-eligible, newly diagnosed myeloma (NDMM) patients. Lenalidomide is approved for maintenance after ASCT until progression, although the optimal duration of maintenance is unknown. In this trial, 80 patients with NDMM received three cycles of lenalidomide, bortezomib, and dexamethasone followed by ASCT and lenalidomide maintenance until progression or toxicity. The primary endpoint was the proportion of flow-negative patients. Molecular response was assessed if patients were flow-negative or in stringent complete response (sCR). By intention to treat, the overall response rate was 89%. Neither median progression-free survival nor overall survival (OS) has been reached. The OS at 3 years was 83%. Flow-negativity was reached in 53% and PCR-negativity in 28% of the patients. With a median follow-up of 27 months, 29 (36%) patients are still on lenalidomide and 66% of them have sustained flow-negativity. Lenalidomide maintenance phase was reached in 8/16 high-risk patients but seven of them have progressed after a median of only 6 months. In low- or standard-risk patients, the outcome was promising, but high-risk patients need more effective treatment approach. Flow-negativity with the conventional flow was an independent predictor for longer PFS