Subscribe: BGD - Latest Articles
http://www.biogeosciences-discuss.net/xml/rss2_0.xml
Added By: Feedage Forager Feedage Grade A rated
Language: English
Tags:
biogeosciences  carbon  discuss https  discussion open  doi org  doi  https doi  https  org  phytoplankton  review discussion  thinsp 
Rate this Feed
Rate this feedRate this feedRate this feedRate this feedRate this feed
Rate this feed 1 starRate this feed 2 starRate this feed 3 starRate this feed 4 starRate this feed 5 star

Comments (0)

Feed Details and Statistics Feed Statistics
Preview: BGD - Latest Articles

BG - recent papers



Combined list of the recent articles of the journal Biogeosciences and the recent discussion forum Biogeosciences Discussions



 



Carbon and nitrogen pools in thermokarst-affected permafrost landscapes in Arctic Siberia

Fri, 16 Feb 2018 20:25:38 +0100

Carbon and nitrogen pools in thermokarst-affected permafrost landscapes in Arctic Siberia
Matthias Fuchs, Guido Grosse, Jens Strauss, Frank Günther, Mikhail Grigoriev, Georgy M. Maximov, and Gustaf Hugelius
Biogeosciences, 15, 953-971, https://doi.org/10.5194/bg-15-953-2018, 2018
Our paper investigates soil organic carbon and nitrogen in permafrost soils on Sobo-Sise Island and Bykovsky Peninsula in the north of eastern Siberia. We collected and analysed permafrost soil cores and upscaled carbon and nitrogen stocks to landscape level. We found large amounts of carbon and nitrogen stored in these frozen soils, reconstructed sedimentation rates and estimated the potential increase in organic carbon availability if permafrost continues to thaw and active layer deepens.



Imprint of Southern Ocean eddies on chlorophyll

Fri, 16 Feb 2018 20:25:38 +0100

Imprint of Southern Ocean eddies on chlorophyll
Ivy Frenger, Matthias Münnich, and Nicolas Gruber
Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-70,2018
Manuscript under review for BG (discussion: open, 0 comments)
Although mesoscale ocean eddies are ubiquitous in the Southern Ocean (SO), their spatial and seasonal association with phytoplankton has not been quantified in detail. We identify over 100,000 eddies and determine the associated phytoplankton biomass anomalies using satellite-based chlorophyll-a (Chl) as a proxy. The Chl anomalies can be explained largely by lateral advection by eddies. The clear impact of eddies on phytoplankton may implicate a downstream effect on SO biogeochemical properties.



Influence of climate variability, fire and phosphorus limitation on vegetation structure and dynamics of the Amazon–Cerrado border

Thu, 15 Feb 2018 20:25:38 +0100

Influence of climate variability, fire and phosphorus limitation on vegetation structure and dynamics of the Amazon–Cerrado border
Emily Ane Dionizio, Marcos Heil Costa, Andrea D. de Almeida Castanho, Gabrielle Ferreira Pires, Beatriz Schwantes Marimon, Ben Hur Marimon-Junior, Eddie Lenza, Fernando Martins Pimenta, Xiaojuan Yang, and Atul K. Jain
Biogeosciences, 15, 919-936, https://doi.org/10.5194/bg-15-919-2018, 2018
Using a dynamic vegetation model, we demonstrate that fire occurrence is the main determinant factor of vegetation changes along the Amazon–Cerrado border, followed by nutrient limitation and interannual climate variability. Although we simulated more than 80 % of the variability of biomass in the transition zone, in many places the simulated biomass clearly does not match observations. The accurate representation of the transition is important for understanding the savannization of the Amazon.



Technical note: Comparison of methane ebullition modelling approaches used in terrestrial wetland models

Thu, 15 Feb 2018 20:25:38 +0100

Technical note: Comparison of methane ebullition modelling approaches used in terrestrial wetland models
Olli Peltola, Maarit Raivonen, Xuefei Li, and Timo Vesala
Biogeosciences, 15, 937-951, https://doi.org/10.5194/bg-15-937-2018, 2018
Emission via bubbling, i.e. ebullition, is one of the main CH4 emission pathways from wetlands to the atmosphere, yet it is still coarsely represented in wetland CH4 models. In this study three ebullition modelling approaches are evaluated. Modeled annual CH4 emissions were similar, whereas temporal variability in CH4 emissions varied an order of magnitude between the approaches. Hence realistic description of ebullition is needed when models are compared to and calibrated against measurements.



Endolithic Boring Enhance the Deep-sea Carbonate Lithification on the Southwest Indian Ridge

Thu, 15 Feb 2018 20:25:38 +0100

Endolithic Boring Enhance the Deep-sea Carbonate Lithification on the Southwest Indian Ridge
Hengchao Xu, Xiaotong Peng, Shun Chen, Jiwei Li, Kaiwen Ta, and Mengran Du
Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-46,2018
Manuscript under review for BG (discussion: open, 0 comments)
Processes involved in the formation of deep-sea carbonate rocks remain controversial. It is reported in present study that endolithic boring may trigger the dissolution of the original calcite above the saturation horizon and thus drive deep-sea carbonate lithification on mid-ocean ridges. The novel mechanism proposed here for non-burial carbonate lithification at the deep-sea seafloor sheds light on the potential interactions between deep-sea biota and sedimentary rocks.



Quantification of the fine-scale distribution of Mn-nodules: insights from AUV multi-beam and optical imagery data fusion

Thu, 15 Feb 2018 20:25:38 +0100

Quantification of the fine-scale distribution of Mn-nodules: insights from AUV multi-beam and optical imagery data fusion
Evangelos Alevizos, Timm Schoening, Kevin Koeser, Mirjam Snellen, and Jens Greinert
Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-60,2018
Manuscript under review for BG (discussion: open, 0 comments)
AUV hydro-acoustic and optical data enhance high resolution quantitative mapping of deep sea hard substrates such Mn-nodules. Machine learning algorithms predict with good accuracy the Mn-nodules abundances over large scale areas utilizing one third of ground truth optical data. Accurate maps of Mn-nodule abundances raise new questions about the role of fine scale geomorphology in nodule formation, provide new insights in deep sea ecological studies, and improve mineral assessment estimations.



Field-warmed soil carbon changes imply high 21st century modeled uncertainty

Thu, 15 Feb 2018 20:25:38 +0100

Field-warmed soil carbon changes imply high 21st century modeled uncertainty
Katherine Todd-Brown, Bin Zheng, and Thomas Crowther
Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-72,2018
Manuscript under review for BG (discussion: open, 0 comments)
The temperature sensitivity of soil carbon loss is a critical parameter for projecting future CO2. Isolating soil temperature response in the field is challenging due to difficulties isolating root and microbial respiration. We use a database of direct-warming soil carbon changes to generate a new global temperature sensitivity. Incorporating this into Earth system models reduces projected soil carbon. But it also shows that variation due to this parameter is as high as all other causes.



Satellite remote sensing reveals a positive impact of living oyster reefs on microalgal biofilm development

Tue, 13 Feb 2018 20:25:38 +0100

Satellite remote sensing reveals a positive impact of living oyster reefs on microalgal biofilm development
Caroline Echappé, Pierre Gernez, Vona Méléder, Bruno Jesus, Bruno Cognie, Priscilla Decottignies, Koen Sabbe, and Laurent Barillé
Biogeosciences, 15, 905-918, https://doi.org/10.5194/bg-15-905-2018, 2018
Using satellite technology and a life-size experiment, we analysed the impact of oyster reefs on mats of microscopic algae that develop within coastal mudflats. We showed that the relationship between microalgae and oysters is not limited to a one-way process where microalgae are a food source to oysters, but that oysters also promote microalgae mats development, presumably by providing nutrients to them. This might yield new insights into coastal ecosystem management.



Microbial Community Structure and Activity Changes in Response to the Development of Hypoxia in a Shallow Estuary

Tue, 13 Feb 2018 20:25:38 +0100

Microbial Community Structure and Activity Changes in Response to the Development of Hypoxia in a Shallow Estuary
Yunjung Park, Sujin Kim, Soonja Cho, Jaeho Cha, and Soonmo An
Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-64,2018
Manuscript under review for BG (discussion: open, 0 comments)
Our work addresses the influences of hypoxia on microbes in three independent aspects (activity, abundance and community structure). The activity and community structure in water column were less affected compared to the sediment (an interesting SRB (sulphate reducing bacteria) succession happened in sediment). Our results also illustrated that the intriguing N dynamics recently discovered in the OMZ (such as AOA dynamics) might also be important in the hypoxic zone.



Ocean acidification and nutrient limitation synergistically reduce growth and photosynthetic performances of a green tide alga Ulva linza

Tue, 13 Feb 2018 20:25:38 +0100

Ocean acidification and nutrient limitation synergistically reduce growth and photosynthetic performances of a green tide alga Ulva linza
Guang Gao, John Beardall, Menglin Bao, Can Wang, Wangwang Ren, and Juntian Xu
Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-1,2018
Manuscript under review for BG (discussion: open, 0 comments)
We investigated the physiological responses of a green tide alga to the combination of ocean acidification and nutrient limitation. Elevated pCO2 did not affect the growth rate when cultured under nutrient replete conditions but reduced it under P limitation. P limitation resulted in a larger inhibition in growth for sporelings compared to adult plants. These findings indicate that ocean acidification and nutrient limitation may hinder the occurrence of green tides in future environment.



Differential response of carbon cycling to long-term nutrient input and altered hydrological conditions in a continental Canadian peatland

Mon, 12 Feb 2018 20:25:38 +0100

Differential response of carbon cycling to long-term nutrient input and altered hydrological conditions in a continental Canadian peatland
Sina Berger, Leandra S. E. Praetzel, Marie Goebel, Christian Blodau, and Klaus-Holger Knorr
Biogeosciences, 15, 885-903, https://doi.org/10.5194/bg-15-885-2018, 2018
Peatlands play an important role in global carbon cycling, but their responses to long-term anthropogenically changed hydrologic conditions and nutrient infiltration are not well known. While experimental manipulation studies, e.g., fertilization or water table manipulations, exist on the plot scale, only few studies have addressed such factors under in situ conditions. Therefore, an ecological gradient from the center to the periphery of a continental Canadian peatland bordering a eutrophic water reservoir, as reflected by increasing nutrient input, enhanced water level fluctuations, and increasing coverage of vascular plants, was used for a case study of carbon cycling along a sequence of four differently altered sites. We monitored carbon dioxide (CO2) and methane (CH4) surface fluxes and dissolved inorganic carbon (DIC) and CH4 concentrations in peat profiles from April 2014 through September 2015. Moreover, we studied bulk peat and pore-water quality and we applied δ13C–CH4 and δ13C–CO2 stable isotope abundance analyses to examine dominant CH4 production and emission pathways during the growing season of 2015. We observed differential responses of carbon cycling at the four sites, presumably driven by abundances of plant functional types and vicinity to the reservoir. A shrub-dominated site in close vicinity to the reservoir was a comparably weak sink for CO2 (in 1.5 years: −1093 ± 794, in 1 year: +135 ± 281 g CO2 m−2; a net release) as compared to two graminoid-moss-dominated sites and a moss-dominated site (in 1.5 years: −1552 to −2260 g CO2 m−2, in 1 year: −896 to −1282 g CO2 m−2). Also, the shrub-dominated site featured notably low DIC pore-water concentrations and comparably 13C-enriched CH4 (δ13C– CH4: −57.81 ± 7.03 ‰) and depleted CO2 (δ13C–CO2: −15.85 ± 3.61 ‰) in a more decomposed peat, suggesting a higher share of CH4 oxidation and differences in predominant methanogenic pathways. In comparison to all other sites, the graminoid-moss-dominated site in closer vicinity to the reservoir featured a  ∼  30 % higher CH4 emission (in 1.5 years: +61.4 ± 32, in 1 year: +39.86 ± 16.81 g CH4 m−2). Low δ13C–CH4 signatures (−62.30 ± 5.54 ‰) indicated only low mitigation of CH4 emissions by methanotrophic activity here. Pathways of methanogenesis and methanotrophy appeared to be related to the vicinity to the water reservoir: the importance of acetoclastic CH4 production apparently increased toward the reservoir, whereas the importance of CH4 oxidation increased toward the peatland center. Plant-mediated transport was the prevailing CH4 emission pathway at all sites even where graminoids were rare. Our study thus illustrates accelerated carbon cycling in a strongly altered peatland with consequences for CO2 and CH4 budgets. However, our results suggest that long-term excess nutrient input does not necessarily lead to a loss of the peatland carbon sink function.



Post-depositional formation of vivianite-type minerals alters sediment phosphorus records

Mon, 12 Feb 2018 20:25:38 +0100

Post-depositional formation of vivianite-type minerals alters sediment phosphorus records
Nikki Dijkstra, Mathilde Hagens, Matthias Egger, and Caroline P. Slomp
Biogeosciences, 15, 861-883, https://doi.org/10.5194/bg-15-861-2018, 2018
We show that post-depositional formation of iron(II) phosphate as vivianite strongly alters the phosphorus record in sediments of the Bornholm Basin (Baltic Sea). These minerals began to precipitate in the lake sediments just after the last lake–marine transition ~ 7.5 kyr BP, migrated downwards and are now a stable feature. Formation of vivianite may affect sedimentary phosphorus records in other systems as well. This should be considered when using such records to reconstruct past environments.



Mesoscale contribution to the long-range offshore transport of organic carbon from the Canary Upwelling System to the open North Atlantic

Mon, 12 Feb 2018 20:25:38 +0100

Mesoscale contribution to the long-range offshore transport of organic carbon from the Canary Upwelling System to the open North Atlantic
Elisa Lovecchio, Nicolas Gruber, and Matthias Münnich
Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-54,2018
Manuscript under review for BG (discussion: open, 0 comments)
We find that the ocean's flow on scales of a few tens to a few hundreds of km has a central role in the lateral redistribution of the organic carbon from the coast to the open ocean. Narrow coastal filaments drive the offshore flux of organic carbon and strongly enhance its availability up to 1000 km from the coast. Eddies extend the flux up to 2000 km offshore containing 30 % of the organic matter in the open waters. Resolving these scales is essential to capture the coastal/open ocean coupling.



Reviews and syntheses: Revisiting the boron systematics of aragonite and their application to coral calcification

Mon, 12 Feb 2018 20:25:38 +0100

Reviews and syntheses: Revisiting the boron systematics of aragonite and their application to coral calcification
Thomas M. DeCarlo, Michael Holcomb, and Malcolm T. McCulloch
Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-77,2018
Manuscript under review for BG (discussion: open, 1 comment)
Understanding the mechanisms of coral calcification is limited by the isolation of the calcifying environment. The boron systematics (B / Ca and δ11B) of aragonite has recently been developed as a proxy for the carbonate chemistry of the calcifying fluid, but a variety of approaches have been utilized. We assess the available experimental B / Ca partitioning data and present a computer code for deriving calcifying fluid carbonate chemistry from the boron systematics of coral skeletons.



Basic and extensible post-processing of eddy covariance flux data with REddyProc

Mon, 12 Feb 2018 20:25:38 +0100

Basic and extensible post-processing of eddy covariance flux data with REddyProc
Thomas Wutzler, Antje Lucas-Moffat, Mirco Migliavacca, Jürgen Knauer, Kerstin Sickel, Ladislav Šigut, Olaf Menzer, and Markus Reichstein
Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-56,2018
Manuscript under review for BG (discussion: open, 0 comments)
Net fluxes of carbon dioxide at the ecosystem level measured by Eddy Covariance are a main source for understanding biosphere-atmosphere interactions. However, there is a need for more usable and extensible tools for post-processing steps of the half-hourly flux data. Therefore, we developed the REddyProc package providing data filtering, gap-filling, and flux-partitioning. The extensible functions are compatible with state-of the art tools but allow easier integration in extended analysis.



First in situ estimations of small phytoplankton carbon and nitrogen uptake rates in the Kara, Laptev, and East Siberian seas

Mon, 12 Feb 2018 20:25:38 +0100

First in situ estimations of small phytoplankton carbon and nitrogen uptake rates in the Kara, Laptev, and East Siberian seas
Bhavya P. Sadanandan, Jang Han Lee, Ho Won Lee, Jae Joong Kaang, Jae Hyung Lee, Dabin Lee, So Hyun An, Dean A. Stockwell, Terry E. Whitledge, and Sang Heon Lee
Biogeosciences Discuss., https//doi.org/10.5194/bg-2018-76,2018
Manuscript under review for BG (discussion: open, 0 comments)
Carbon and nitrogen uptake rates by small phytoplankton (0.7–5 μm) in the Kara, Laptev, and East Siberian seas in the Arctic Ocean were quantified using in situ isotope labelling experiments for the first time as part of the NABOS (Nansen and Amundsen Basins Observational System) program during August 21 to September 22, 2013. The depth integrated C, NO3, and NH4+ uptake rates by small phytoplankton showed a wide range from 0.54 to 15.96 mg C m−2 h−1, 0.05 to 1.02 and 0.11 to 3.73 mg N m−2 h−1, respectively. The contributions of small phytoplankton towards the total C, NO3, and NH4+ was varied from 24 to 89 %, 32 to 89 %, and 28 to 89 %, respectively. The turnover times for NO3 and NH4+ by small phytoplankton during the present study point towards the longer residence times (years) of the nutrients in the deeper waters, particularly for NO3. Relatively, higher C and N uptake rates by small phytoplankton obtained during the present study at locations with less sea ice concentrations points towards the possibility of small phytoplankton thrive under sea ice retreat under warming conditions. The high contributions of small phytoplankton towards the total carbon and nitrogen uptake rates suggest capability of small size autotrophs to withstand in the adverse hydrographic conditions introduced by climate change.



Phosphorus limitation and heat stress decrease calcification in Emiliania huxleyi

Fri, 09 Feb 2018 20:25:38 +0100

Phosphorus limitation and heat stress decrease calcification in Emiliania huxleyi
Andrea C. Gerecht, Luka Šupraha, Gerald Langer, and Jorijntje Henderiks
Biogeosciences, 15, 833-845, https://doi.org/10.5194/bg-15-833-2018, 2018
Calcifying phytoplankton play an import role in long-term CO2 removal from the atmosphere. We therefore studied the ability of a representative species to continue sequestrating CO2 under future climate conditions. We show that CO2 sequestration is negatively affected by both an increase in temperature and the resulting decrease in nutrient availability. This will impact the biogeochemical cycle of carbon and may have a positive feedback on rising CO2 levels.



Explaining CO2 fluctuations observed in snowpacks

Fri, 09 Feb 2018 20:25:38 +0100

Explaining CO2 fluctuations observed in snowpacks
Laura Graham and David Risk
Biogeosciences, 15, 847-859, https://doi.org/10.5194/bg-15-847-2018, 2018
Winter carbon dioxide (CO2) respiration from soils is a significant and understudied component of the global carbon (C) cycle. In this study, we were able to show with a field campaign and a model how windy (advective) conditions can affect the usually slow (diffusive) transport of CO2 from soils and out of snowpacks. This research is important to help with understanding winter CO2 dynamics, especially for continued accurate accounting of the annual global C cycle.



Virus-mediated transfer of nitrogen from heterotrophic bacteria to phytoplankton

Fri, 09 Feb 2018 20:25:38 +0100

Virus-mediated transfer of nitrogen from heterotrophic bacteria to phytoplankton
Emma J. Shelford and Curtis A. Suttle
Biogeosciences, 15, 809-819, https://doi.org/10.5194/bg-15-809-2018, 2018
This work demonstrates that lysis by viruses facilitates the transfer of nitrogen to phytoplankton in the ocean, and thus viruses are key players in nitrogen cycling in the oceans and in maintaining oxygen production by marine primary producers.



Wet–dry cycles impact DOM retention in subsurface soils

Fri, 09 Feb 2018 20:25:38 +0100

Wet–dry cycles impact DOM retention in subsurface soils
Yaniv Olshansky, Robert A. Root, and Jon Chorover
Biogeosciences, 15, 821-832, https://doi.org/10.5194/bg-15-821-2018, 2018
Dissolved organic matter (DOM) fate in soils can be impacted by frequent wet–dry cycles that occur in the subsoil environment. This study provides direct evidence that wet–dry cycles altered both composition and spatial distribution of organic carbon on a complex soil matrix. Therefore transformation of soils with a wet environment to higher fluctuation in soil moisture, as predicted by climate models, may alter the interactions between DOM and soil surfaces.