AOGS 2015 - Browse Abstracts

Browse by Session - Select Session:
Oral Presentations - Browse by Section and Presentation Day
Poster Presentations - Browse by Section


Poster Presentations of Section BG

Print this page

  BG01-D3-PM2-P-004 (BG01-A002)
Paired Coral Sr/Ca and d18O from Timor Waters: Seasonal Variation of SST and Salinity at the ITF Exit Passage
Sri Yudawati CAHYARINI1#+, Intan Suci NURHATI2, Miriam PFEIFFER3, Edvin ALDRIAN4, Wolf-Ch. DULLO5, Steffen HETZINGER5
1 Research Centre for Geotechnology, The Indonesian Institute of Sciences, Indonesia, 2 SMART, Singapore, 3 RWTH Aachen University, Germany, 4 Agency for Meteorology Climatology and Geophysics, Indonesia, 5 GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany
#Corresponding author: +Presenter

Long time series sea-surface temperature (SST) and salinity (SSS) data from the Indonesian Throughflow (ITF) is required to more understand the global ocean circulation related to Indo-Pacific climate. In this study paired coral d18O and Sr/Ca measurements spanning the period 1914-2004 is used to reconstruct both SST and SSS. These records reveal the impact of Indo-Pacific climate variations on SST and SSS at the exit passage of the ITF: Coral Sr/Ca-based SST and d18Osw–based SSS records capture the strong seasonality at Timor that results from the regional monsoon forcing; on interannual timescales, both coral SST and coral SSS are influenced by the Indian Ocean Dipole (IOD), while ENSO influences SST only; there is a strong correlation between Timor and IOD on decadal variations with the decadal IOD leading Timor SST and SSS by about 1.6 to 2 years; coral Sr/Ca thermometry improves SST reconstruction in the ITF passageway and over the Indonesian maritime region rather than using coral d18O only; coral SST records exhibits more pronounced low-frequency variability compared to the reanalysis SST product. However,it is still required longer time series coral SST(SSS) to estimate the more accurate low-frequency SST (SSS) variability, which improve the detection of warming trends in this climatically important region.

  BG01-D3-PM2-P-005 (BG01-A004)
Paleohidrography Reconstruction of the Halmahera Sea as a Part of Western Pacific Warm Pool
Luli GUSTIANTINI1#+, Franck BASSINOT2, Rina ZURAIDA3, Catherine KISSEL2, Khoiril Anwar MARYUNANI1, Yahdi ZAIM1
1 Institute Technology of Bandung, Indonesia, 2 Laboratoire des Sciences du Climat et l'Environnement (LSCE), France, 3 Marine Geological Institute, Indonesia
#Corresponding author: +Presenter

As a part of Western Pacific warm pool Halmahera sea provide essential data for understanding air-ocean interaction that distribute heat and moisture from tropic to the high latitude. Furthermore, Halmahera sea is also situated at a secondary path of ITF route, as a consequent its dynamic plays a role in modifying ITF water mass that influence the characteristics of Thermohaline circulation. Therefore we study the paleohidrography of Halmahera sea by combining d18O and Mg/Ca analysis on planktonic foraminiferaG. ruber, taken from a 39 m giant sediment core. The age model is reconstructed based on 14C dates also conducting on planktonic foraminifera.

d18O record display significant glacial – interglacial fluctuation by 2 ‰ difference value, while the LGM and Holocene SST difference approximately 2.30C. We learn that although the SST pattern exhibit good correlation to the global SST record, the calcite d18O (d18Oc) value indicate different trend particularly during early Holocene. The d18Oc value is still extremely declined until approximately 6 ka, anti-correlated with the seawater d18O (d18Osw) record that is still extremely increased. Better correlation value between d18Oc and the d18Osw compared with that between d18Oc and SST suggest local dynamics in this case salinity variability play a role in Halmahera sea hydrography. The precipitation was considered abruptly increase in the beginning of warmer episode resulting extremely decrease in salinity that influence the d18O value.

  BG01-D3-PM2-P-006 (BG01-A013)
Soft Tissue, Collagen and Significant 14C Content in Dinosaur Bones - What Does it Mean?
1 Paleo Group, United States, 2 Paleo Group, France, 3 Paleo Group, Poland, 4 Retired, France, 5 Mt Blanco Fossil Museum, United States
#Corresponding author: +Presenter

We examine the implications of several experiments that isolated constituent components of fossil material: 1) Removing carbonates from some dinosaur bones with weak organic acids revealed soft tissue, osteocytes and fibrous collagen [Schweitzer et al. 2005, Armitage et al. 2014]; 2) Removing calcium carbonate from calcareous fossil wood embedded in rock within a coal mine yielded wood that is both flexible and burnable [Dawson 1846]; 3) Carbon-14 testing of collagen and bioapatite in dinosaur bone samples with Accelerator Mass Spectrometry and conventional beta methods, following procedures that minimize the contribution of instrument and allochthonous contamination, yielded pmC levels in the range of 0.61 to 5.6 (22,020±50 to 41,010±220 years BP) [Miller et al. AGU 2014]. These numbers are notably higher than pmC results for coal [Baumgardner et al. AGU 2003]. The validity of Carbon-14 levels in dinosaur bones is reinforced by δ13C values for various bone fractions.  δ15N levels, equated to a ~1:1 ratio of δ15N to collagen, [Buhay et al. 2012] in numerous dinosaur bone samples excavated in a formerly glaciated region, Alberta, Canada, are an order of magnitude higher than the maximum of 0.35% collagen content found in ice-free areas of Montana, United States. This indicates improved preservation due to ice age cooling [Ostrom et al. 1993]. While other experiments have shown that preservation of polymers in bone may be enhanced by the presence of blood iron [Schweitzer et al. 2013], the evidence above points to ages for the fossils that starkly diverge from what is expected. This opens new avenues for research in several disciplines. The compression of the timeframe that these results indicate also raises the specter that asteroid and comet impacts and explosions present a greater risk to mankind and Earth's environment than is currently assumed.

  BG01-D3-PM2-P-007 (BG01-A014)
Archaeological and Historical Evidence for Significant Catastrophes within the Holocene Period
1 Paleo Group, United States, 2 Mt Blanco Fossil Museum, United States, 3 Retired, France, 4 Paleo Group, Poland, 5 Paleo Group, France
#Corresponding author: +Presenter

Archaeological evidence of distinct dinosaurian depictions exists world-wide from a carving of a Stegosaurus-type dinosaur on a Buddhist temple in Cambodia to Brontosaurus-type dinosaurs on the brass crypt of a late 15th century Catholic Bishop in England to a 3rd century mural on the floor of a mansion in Israel. Two chateaus built by King Francois I of France in the 1530’s contain many beautiful carvings of distinct dinosaur-like creatures. In the United States there is a brontosaurus-type dinosaur on a wall of Natural Bridge Monument in Utah. Archaeologists in the Acambaro area of Mexico have discovered hundreds of fire-hardened clay figurines of dinosaur-like creatures and Peruvian museums have distinct dinosaur depictions carved on burial stones discovered in graves of deceased humans. 14C dating of dinosaur bones has been reported by several teams of scientists including that of a marine reptile in Western Europe and 10 dinosaurs in North America as demonstrated by Seiler et al (AOGS Singapore Conference, 2012). Have there been one or more massive cataclysms that killed off most dinosaurs leaving some survivors, just as there have been human survivors of catastrophes reported world-wide by all peoples of the Earth? [Holocene Impact Working Group, Abbott et al, 2004].

  BG04-D3-PM2-P-007 (BG04-A001)
Effects of Ocean Acidification on Nitrogen Uptake by Marine Diatoms Phaeodactylum Tricornutum and Thalassiosira Weissflogii
Dongmei LI#+, Wenfang LIN, Haizheng HONG, Dalin SHI
Xiamen University, China
#Corresponding author: +Presenter

In marine ecosystems nitrogen exists in a myriad of chemical forms, among which nitrate (NO3-) and ammonium (NH4+) are the major nitrogenous nutrients supporting primary production. It is known that the rate of NO3- uptake by phytoplankton is often reduced in the presence of NH4+, although the degree of inhibition is highly variable between phytoplankton species, with nutrient prehistory, and under the impacts of environmental variables. More recent studies show that ocean acidification could decrease microbial nitrification rates and hence alter the ratio of NH4+/NO3- in surface seawaters. How such an indirect effect coupled with the potential direct effects of ocean acidification may influence the interaction between NH4+ and NO3- remains largely unknown. In this laboratory study, the inhibitory effect of NH4+ on NO3- uptake by the nitrogen-starved and nitrogen-limited diatoms Phaeodactylum tricornutum and Thalassiosira weissflogiiwas examined under different carbon dioxide (CO2) conditions. Our preliminary data show that both NO3- uptake and nitrate reductase (NR) expression were down-regulated as CO2 increased from 400 ppm to 800 ppm in both nitrogen-limited and starved P. tricornutum. However, in T. weissflogii, elevated pCO2 up-regulated NO3- uptake and NR expression under nitrogen limitation, whereas it down-regulated them under nitrogen starvation. In both P. tricornutum and T. weissflogii, the presence of NH4+ inhibited NO3- uptake and NR expression at either 400 ppm or 800 ppm CO2, and the inhibitory effects were similar at the two different pCO2 levels. These results suggest that ocean acidification may have different effects on NO3- uptake and incorporation in different diatom species and with different nutrient prehistory. Further study is in progress to elucidate underlying mechanisms responsible for the above observation, and to reveal how other global change environmental factors would modify the effects caused by ocean acidification.

  BG04-D3-PM2-P-008 (BG04-A002)
Mechanistic Understanding of the Effects of Ocean Acidification on the Dominant Marine N2 Fixing Cyanobacterium Trichodesmium IMS101
Rong SHEN1#+, Siwei CHANG2, Haizheng HONG1, Dalin SHI1
1 Xiamen University, China, 2 College of the Environment and Ecology, Xiamen University, China
#Corresponding author: +Presenter

The marine filamentous N2-fixing cyanobacterium Trichodesmium spp. has been shown to be exceptionally sensitive to ocean acidification (OA). Previous studies showed OA generally enhances N2 fixation, carbon fixation and growth in Trichodesmium cultured in the nutrient-replete artificial seawater medium YBCII. The beneficial effects have been attributed largely to the down-regulation of CCM, from which the energetic resources saved could be reallocated to other cellular processes. However, it has been reported that OA has negative effects on the growth and N2 fixation in the same diazotroph cultured in iron-limited natural seawater based medium (Aquil*). In this study, using these two different media, we systematically examined and compared the effects of OA on Trichodesmium erythraeum IMS101 under iron-replete conditions. The results confirmed that OA had positive effects on Trichodesmium grown in YBCII medium, whereas no effect was observed with the diazotroph grown in iron-sufficient Aquil* medium. By varying pCO2 and pH of the medium independently, we found that elevated pCO2 indeed stimulated the growth and N2 fixation of Trichodesmium, while decreasing pH had the opposite effects. We proposed that elevated pCO2 down-regulated the CCM and thus benefited Trichodesmium in both YBCII and Aquil* media; however, decreasing pH had opposite effects in the two media due most likely to the difference in trace metal chemistry in the two systems. Furthermore, in order to examine whether cellular energy could be reallocated among different metabolic pathways in the organism, we added ammonium to inhibit N2 fixation. The results showed that when N2 fixation was suppressed as demonstrated by the disappearance of diazocytes and the dramatically diminished nitrogenase activity, the POC and PON was significantly increased. It therefore suggested that energy saved from one cellular process such as the CCM and N2 fixation could be reallocated and utilized in other metabolic pathways in Trichodesmium.

  BG04-D3-PM2-P-009 (BG04-A003)
Ocean Acidification Increases the Iron Demand for the Growth and N2 Fixation in Trichodesmium and Croscosphaera
Wenfang LIN#+, Rong SHEN, Haizheng HONG, Dalin SHI
Xiamen University, China
#Corresponding author: +Presenter

Dinitrogen (N2)-fixing cyanobacteria Trichodesmium spp.and Crocosphaera spp. contribute significantly to biological N2 fixation in the contemporary ocean. Both of the diazotrophs are found to dwell in oligotrophic regions of the ocean where very low concentrations of iron (Fe) in surface waters often limit their growth and N2 fixation. It has recently been demonstrated that ocean acidification could decrease the bioavailability of Fe in seawaters, which therefore will likely lead to intensified Fe limitation for the growth and N2 fixation in Trichodesmium and Crocosphaera. In the present study, we cultured Trichodesmium erythraeum IMS101 and Crocosphaera watsonii WH8501 under different carbon dioxide (CO2) conditions using natural seawater based Aquil* medium, and measured their growth rates, N2 fixation rates, and cellular Fe quotas. The results show that as CO2 increased from 400 ppm to 800 ppm, the maximum growth rate and N2 fixation rate of both cyanobacteria decreased slightly. More strikingly, the half-saturation constant for growth with respect to Fe increased by more than three folds, a substantial change much more significant than that in the concentrations of bioavailable Fe (Fe'). These results suggested that ocean acidification not only will alter the concentration of bioavailable iron, but also will change the cellular requirement of Fe in the dominant marine N2-fixing cyanobacteria.

  BG04-D3-PM2-P-010 (BG04-A004)
Interactive Effects of Light, Nitrogen Source and Carbon Dioxide on Energy Metabolism in the Diatom Thalassiosira Pseudonana
Weiying LI#+, Dongmei LI, Wenfang LIN, Haizheng HONG, Dalin SHI
Xiamen University, China
#Corresponding author: +Presenter

As the Earth progresses further into the anthropocene, marine phytoplankton are likely confronted with an aquatic milieu featuring higher light intensity, larger proportion of ammonium (NH4+) than nitrate (NO3-) as the nitrogen source, and more carbon dioxide (CO2), caused either individually or jointly by intensified stratification, as a result of warming, and ocean acidification. To seek a mechanistic understanding of how marine primary producers would balance energy harvesting and dissipation to cope with the changing environment, the centric diatom Thalassiosira pseudonana was cultured under an array of conditions characterizing a matrix of irradiance (30 or 250 μmol photons m−2 s−1), nitrogen source (NO3- or NH4+), and CO2 level (400 or 800 ppm). The results showed that light intensity had the predominant effect on the growth rate of T. pseudonana, followed by nitrogen source, while pCO2 had no obvious effect. Under high light, cells grown on NO3- up-regulated the protein expression and activity of nitrate reductase (NR), which helped dissipate excessive cellular energy and was in good agreement with higher cellular nitrogen uptake and protein content. However, elevated pCO2 reduced the protein expression and activity of NR, which resulted in lower particulate organic nitrogen (PON) and total protein content, consequently leading to an increase in the C:N ratio. In the meantime, elevated pCO2 stimulated T. pseudonana to produce more carbohydrate to store excessive energy. When NH4+ was the sole nitrogen source, there was no NR activity and expression. As a result, in order to compensate for the absence of nitrate assimilation, fatty acid biosynthesis, which consumed more energy than other carbohydrate, was induced significantly, in particular under HL. Taken together, this study demonstrates that T. pseudonana could adjust the metabolic pathways and biochemical composition to balance the cellular energy budget to cope with the changing environment likely encountered in the future ocean.

  BG04-D3-PM2-P-011 (BG04-A010)
The Effect of Desiccation on the Emission of Volatile Bromocarbons from Macroalgae
1 University of East Anglia, United Kingdom, 2 University of Malaya, Malaysia
#Corresponding author: +Presenter

Exposure of intertidal macroalgae during low tide has been linked to the emission of a variety of atmospherically-important trace gases into the coastal atmosphere. In recent years, several studies have investigated the role of inorganic iodine and organoiodides as antioxidants and their emission during exposure to combat oxidative stress, yet the role of organic bromine species during desiccation is less well understood. In this study the emission of dibromomethane (CH2Br2) and bromoform (CHBr3) during exposure and desiccation of two common temperate macroalgae, Fucus vesiculosus and Ulva intestinalis, is reported. Determination of the impact exposure may have on algal physiological processes is difficult as intertidal species are adapted to desiccation and may undergo varying degrees of desiccation before their physiology is affected. For this reason we include comparisons between photosynthetic capacity (Fv/Fm) and halocarbon emissions during a desiccation time series. In addition, the role of rewetting with freshwater to simulate exposure to rain was also investigated. Our results show that an immediate flux of bromocarbons occurs upon exposure, followed by a decline in bromocarbon emissions. We suggest that this immediate bromocarbon pulse may be linked to volatilisation or emissions of existing bromocarbon stores from the algal surface rather than the production of bromocarbons as an antioxidant response.

  BG05-D3-PM2-P-009 (BG05-A003)
GOSAT Satellite Carbon Dioxide Data Assimilation Experiment Based on Tan-Tracker System
Rui HAN+, Xiangjun TIAN#
Institute of Atmospheric Physics, Chinese Academy of Sciences, China
#Corresponding author: +Presenter

The performance of a joint data assimilation system(Tan-Tracker) based on PODEn4Dvar assimilation method, which intent to reach high flexibility and high computational efficiency, has been assessed by designing a data assimilation experience of GOSAT satellite carbon dioxide data as observations. Firstly, We simulatedatmospheric 3-D CO2 concentrations and CO2 surface fluxes (CFs) of the first half year of 2010 using GEOS-Chem(Goddard Earth Observing System-Chemistry) model. Subsequently, the simulated results, worked as background field, were put into the Tan-Tracker system to assimilate the Japanese Greenhouse Gases Observation Satellite (GOSAT) column average dry-air mole fraction data of CO2(XCO2), data version ACOS_V3.3, to optimize the concentrations together with CFs at the same assimilation window to get the assimilated atmospheric 3-D CO2 concentrations and CFs. Simulated and assimilated retrieved XCO2model(XCO2Sim and XCO2TT) at the satellite scan location, latitude and longitude, were compared with the GOSAT XCO2(XCO2Obs) by month. Root-Mean Square Error(RMSE) of XCO2model and XCO2Obs was dramatic decline(about 40%) after assimilating, with the change of correlation coefficient (CORR) of XCO2model and XCO2Obswas less obvious, for each month. A marked fall of errors between XCO2model and XCO2Obs were found at Northern Africa(Sahara), Indian Peninsula, Southern Africa, Southern North America and Western Australia after assimilating. While the assimilated result of the latter half of year 2010 was not as good as simulated, futher research of the usability and parameters correction of GOSAT XCO2 data is needed.

  BG05-D3-PM2-P-010 (BG05-A009)
Signature of Fossil Fuel Emission of CO2 from Large Point Sources in GOSAT XCO2 Data
Rajesh JANARDANAN ACHARI1#+, Tomohiro ODA2, Shamil MAKSYUTOV1, Johannes KAISER3, Makoto SAITO1, Alexamder GANSHIN4, Yukio YOSHIDA1, Tatsuya YOKOTA1
1 National Institute for Environmental Studies, Japan, 2 Colorado State University, National Oceanic and Atmospheric Administration, United States, 3 Max Planck Institute for Chemistry, Germany, 4 Central Aerological Observatory, Russian Federation
#Corresponding author: +Presenter

We analyzed three and half years (June 2009 through December 2012) of GOSAT column-averaged CO2 (XCO2) data for presence of fossil fuel emission signature by estimating XCO2 abundance at each observation location where high-resolution (0.10) inventory-based (ODIAC) transport model simulated above 0.1 ppm enhancement in fossil XCO2, relative to mean clean background observations in global 100x100 regions. Corrections for contributions from biospheric and biomass burning fluxes were made based on simulated values using high resolution fluxes from Vegetation Integrative SImulator of Trace gases (VISIT) model and Global Fire Assimilation System (GFAS). We assume influence from oceanic CO2 fluxes to continental fine-scale variability is relatively small. Observed and simulated fossil fuel enhancements were clustered and averaged according to the simulated discrete enhancement levels (each 0.2 ppm levels) for each month and 100x100 region. The results were aggregated for the whole analysis period and the observed values were linearly regressed against simulated ones. Results show near linear relations between observed and inventory based XCO2 enhancements, for the globe and  large continental regions which contribute significantly to the global atmospheric CO2 through emission from fossil fuel use. Our finding of linear scaling between satellite derived and observation based fossil fuel enhancements shows the utility of GOSAT to verify fossil fuel emission inventory. Considerably better performance can be expected for emission monitoring if sufficient number of observations of Large Point Sources and surrounding cleaner areas by GOSAT or similar satellites.

  BG08-D3-PM2-P-005 (BG08-A001)
Effects of Nitrification and Urease Inhibitors on Greenhouse Gases Emissions and Crop Yield in a Wheat-Maize Double Cropping System : A Two-Year Field Study
Zichao ZHAO+, Yuefeng SHI, Cong XU, Wenliang WU, Fanqiao MENG#
China Agricultural University, China
#Corresponding author: +Presenter

Wheat and maize are the most widely grown cereals in North China. Nitrogen (N) fertilizer has been employed by famers as one of the most effective measures since 1980s in the region to maintain high crop yield of wheat and maize, while the negative environmental impacts including Greenhouse Gas (GHG) emission have also been intensively addressed. Nitrification and urease inhibitors are proposed as the alternatives to decrease nitrous oxide (N2O) emission without decrease of crop yield. To evaluate the effects of nitrification and urease inhibitors, we conducted a two year-round measurements of N2O and CH4 fluxes in the experiment consisting five treatments of 1) no N fertilizer (CK), 2) urea (U), 3) urea + DMPP (NI), 4) urea + NBPT (UI) and 5) urea + DMPP + NBPT (NIUI) on a wheat–maize cropping system in China. The study found that NI, UI and NIUI reduced N2O emission by 48.3%, 16.4% and 35.5% compared with U treatment in 2012-2013, and 54.1%, 33.1% and 45.7 % in 2013-2014. Nitrification and urease inhibitors significantly decreased the CH4 uptake (16.3-49% in 2012-2013 and 32.9-54.2% in 2013-2014). The crop yields of NI, UI and NIUI were 4.0%, 2.0% and 6.8% higher than that of U in 2012-2013 and 11.7%, 8.3%, 13.1% higher in 2013-2014. Greenhouse gas intensity (GHGI) of CK, U, NI, UI and NIUI were 63.8, 97.8, 48.0, 80.2 and 58.4 g CO2-eq kg-1 yield (2012-2013) and 68.4, 125.0, 51.2, 76.5 and 59.1kg CO2-eq kg-1 yield (2013-2014) respectively. These results indicated that nitrification and urease inhibitors could effectively mitigate the emission of N2O, whilst increasing yield and significantly reducing GHGI. The combination of DMPP with urea could be a better farming measure to reduce N2O emission and improve the crop yield in North China.

Keywords: nitrification inhibitor, urease inhibitor, N2O, CH4, crop yield.

  BG08-D3-PM2-P-006 (BG08-A002)
Maintaining of High Crop Yield and GHG Emission Reduction Can Be Achieved by Optimized Fertilization: Evidences from a 4-Year Field Experiments
Yuechen TAN1+, Dongxue LIU1, Wenliang WU1, Jørgen E. OLESEN2, Fanqiao MENG1#
1 China Agricultural University, China, 2 Aarhus University, Denmark
#Corresponding author: +Presenter

Many field experiments have been conducted to investigate the reduction of Greenhouse Gas (GHG) emission by diverse farming measures, and these studies are mostly within the short period of 1-2 years. China, including many other developing countries, faces the challenge of sustainably maintaining a high crop yield and reducing of GHG emission. We established a field experiment with optimized nitrogen (N) fertilization management (OPT), 1/3 lower of N than local farmer’s practice (FP) from 2008 to 2012 and monitored the GHG emission and crop yield dynamics on a typical intensive winter wheat-summer maize cropping system in North China. The N2O emission from OPT was 36.8%, 8.9% and 35.1% lower than that of FP during the 1st, 2nd and the 4th rotation year, respectively. The CH4 uptake from OPT was 20.5% and 41.3% higher than that of FP treatment the 1st and the 4th rotation year, but 11% lower in the 2nd rotation year. OPT had significant higher or similar crop yield compared with FP; annual nitrogen utilization efficiency (NUE) of OPT was 12-14% higher than that of FP during the four years period of experiment. Inorganic N (NO3- and NH4+) of topsoil for FP treatment was significantly higher than that of OPT, indicating a higher risk of N entering into water bodies by conventional farmer’s practice. OPT treatment significantly reduced net global warming potential (NGWP) and Greenhouse gas intensity (GHGI) by 23.6-34.9% and 24.2-37.7%, respectively, compared with FP treatment during the experimental period. Our results suggest that optimized N management (up to 1/3 of N reduction) can achieve the dual goals of maintaining high crop yield while reducing the GHG emission in the intensified farming region of North China. High variations among the four cropping years also highlighted the necessities of long-term field experiments on GHG reduction by various farming practices.

  BG08-D3-PM2-P-007 (BG08-A003)
Impacts of Natural Factors and Management Practices on Greenhouse Gas Emissions in the Intensively Managed Agricultural Region of North China: A Meta-analysis
Cong XU1+, Jianting XU1, Wenliang WU1, Jørgen E. OLESEN2, Fanqiao MENG1#
1 China Agricultural University, China, 2 Aarhus University, Denmark
#Corresponding author: +Presenter

North China, the most important wheat and maize production region, could have a significant impact on greenhouse gas (GHG) emission and the country’s food security. A quantitative understanding of the impact is strongly necessary for screening appropriate mitigation technologies to achieve the dual goals of maintaining high crop yield and reducing the GHG emission. A meta-analysis (76 published studies on 21 sites) was conducted on the analysis of effects of natural factors and farming measures on area-scaled and yield-scaled GHG (CO2-eq) emission in North China. We found that soil pH, annual mean temperature and soil organic matter had significant positive correlation with annual N2O emission and yield-scaled GWP. Higher nitrogen (N) fertilization (with the range of 100–600 kg N ha−1 yr-1) significantly increased N2O emission and area-scaled GWP. The highest crop yield occurred at 400-500 kg N ha-1 yr-1 and the yield-scaled GWP was remarkably lower than that of 500-600 kg N ha-1 yr-1 (84.9 vs. 103.6 kg CO2-eq Mg-1). Annual N2O emission under straw return (3127 g N2O-N ha-1) was significantly higher than that of no straw return (2586 g N2O-N ha-1) and straw return showed a lower yield-scaled GWP compared with no straw return (84.1 vs. 95.7 kg CO2-eq Mg-1) which was mainly attributed to the increment in crop yield under straw return. No tillage (NT) significantly decreased N2O emission by 9.4% for wheat season and 30.4% for maize season than tillage (T), however there was no significant differences on crop yield, area-scaled GWP and yield-scaled GWP between T and NT. Our results suggest that there indeed are potentials to reduce GHG emissions without decreasing of crop yield through innovating farming practices in North China.

Keywords: agricultural intensification, natural factors, farming practices, Greenhouse Gas emission, North China

  BG10-D3-PM2-P-007 (BG10-A005)
Improving Crop Yield and Soil Organic Matter by Straw Return in China, Results from Long-Term Experiments
Jinzhou WANG1+, Minggang XU2#, Wenju ZHANG2, Wendy WANG3
1 Chinese Academy of Agricultural Sciences, China, 2 Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, China, 3 University of Maryland, United States
#Corresponding author: +Presenter

Straw incorporation is highly recommended in China during the last decades for its positive effects on sustainable soil fertility and crop productivity, but the extent and duration of these effects remain uncertain. In this study, we analyzed data from 76 paired trials of long-term (>10 years) straw return vs. straw removal treatments with similar management practices in the major agricultural zones of China. Compared with straw removal, continuous straw return significantly increased crop yield, SOC and TN. At various durations ranging from 10 to 30 years, the increase fluctuated around 7.0%, 10.1% and 11.0% for yield, SOC and TN, respectively. This result implied that the improvements of straw return on sustainable crop production and SOC accumulation can be effective in a short-term (~10 years), but limited in a long-term period. The increments of crop yield and stocks of SOC and TN, were positively and linearly related to the amount of straw input (e.g., straw-C and -N), indicating that direct C and nutrients input from straw are the major contributors to those increments. Furthermore, based on the mean value of straw-C sequestration efficiency, i.e., 7.7%, 10.3% and 9.4% for corn, wheat and rice straw, respectively, the gross SOC sequestration potential under 100% straw return was estimated to be 281.7 Tg C in 18 years in China. Our results highlight that straw return is an effective way to improve crop productivity, but has limited effect on long-term soil C sequestration.

Keywords: straw return; soil organic carbon, crop yield, long-term experiment

  BG10-D3-PM2-P-008 (BG10-A008)
Decomposition of Organic Carbon in Soil Particles and Their Responses to Temperature Change
Wenjuan SUN1#+, Fan DING1, Hong XU2, Yao HUANG1
1 Institute of Botany, Chinese Academy of Sciences, China, 2 Beijing Normal University, China
#Corresponding author: +Presenter

To investigate the CO2 emission from soils with different textures, we conducted a 107-day incubation experiment. The soils were sampled from forest, grassland, cropland (upland and paddy soil) in China. The incubation was conducted over three short-term cycles of changing temperature from 5°C to 30°C. Results indicated that CO2 emissions from sand (> 50 μm), silt (2-50μm), and clay (<2μm) particles increased exponentially with increasing temperature. The sand fractions emitted more CO2 (CO2-C per unit fraction-C) than the silt and clay fractions in forest, grassland and cropland soils. The temperature sensitivity of the CO2emission from soil particles, which is expressed as Q10, decreased in the order clay>silt>sand. The Q10 of bulk soil decreased in the order synthetic fertilizer-applied upland >manure-applied upland> grassland >forest. Our results suggested that the decomposition of organic carbon in fine-textured soils that are rich in clay or silt could be more sensitive to warming than those in coarse sandy soils and SOC might be more vulnerable in fertilized cropland soil than in native grassland and forest soils under future warming.

  BG10-D3-PM2-P-009 (BG10-A009)
Contributions of Wheat and Maize Residues to Soil Organic Carbon Under Long-Term Rotation in North China
Wenju ZHANG1#+, Jinzhou WANG2, Wendy WANG3, Minggang XU1, Xueyun YANG4, Shaomin HUANG5
1 Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, China, 2 Chinese Academy of Agricultural Sciences, China, 3 University of Maryland, United States, 4 Northwest Agricultural and Forestry Science and Technology University, China, 5 Institute of Plant Nutrition, Resources and Environment, Henan Academy of Agricultural Sciences, China
#Corresponding author: +Presenter

Soil organic carbon (SOC) dynamics in agro-ecosystem is largely influenced by cropping. However, quantifying the contributions of various crops has been lacking. Here we employed a stable isotopic approach to evaluate the contributions of wheat and maize residues to SOC at three long-term experiment sites in north China. Soil samples were collected from 0-20, 20-40, 40-60, 60-80 and 80-100 cm after 13 and 20 years of wheat-maize rotation, and SOC and its stable 13C composition were determined. Our data showed that the δ13C value of SOC varied, on average, from -22.1‰ in the 0-20 cm to -21.5‰ in the 80-100 cm. Based on a mixing model method, carbon input through maize residues ranged from 35% to 68% whereas the contribution of maize residues to SOC (0-40 cm) was only 28-40%. Our analyses suggested that the retention coefficient might be 8.0-13.6% for maize residues and 16.5-28.5% for wheat residues. The large difference in the retention coefficient between maize and wheat residues was due to the differences in the quality of residues and probably also in the cumulative effective temperature during the growing season. Our study highlighted the importance of cropping management on carbon sequestration in agricultural lands.

  BG11-D3-PM2-P-012 (BG11-A003)
Ammonium Distribution in the South China Sea Based on Shipboard High Resolution Measurements
Yifan ZHU1+, Minhan DAI1#, Yong ZHU2, Dongxing YUAN1
1 Xiamen University, China, 2 The Second Institute of Oceanography (SIO), State Oceanic Administration (SOA), China
#Corresponding author: +Presenter

As the most reactive species of dissolved inorganic nitrogen in seawater, oceanic ammonium (NH4+) plays a vital role in marine ecological processes and therefore a key component in marine nitrogen cycle. However, reports on ammonium in the oligotrophic ocean have been rare due to its extremely low concentrations and proneness to contamination during sampling and analysis. A batch flow analyzer with solid phase extraction (SPE) and fluorescence detection was used to measure ammonium during a cruise to the South China Sea (SCS) in May-July 2014. Based on high spatial resolution depth profiles of the dissolved inorganic nitrogen (DIN) species (ammonium, nitrite and nitrate) and chlorophyll a, we found that the ammonium concentrations ranged from the limit of detection (0.7 nM) to 133.4 nM NH4+. While the primary nitrite maximum(PNM, 81.9-339.5 nM) was observed in all stations, subsurface ammonium maximum (AM, 24.4-133.4 nM) was observed in some stations but not in others. When AM observed they usually occurred between 50 and 100 m near deep chlorophyll maximum (DCM) in association with PNM we measured during the cruise. This suggests that in summer stratified oligotrophic waters, microbial oxidation of ammonium (nitrification) might be a key process that generated nitrite maxima. In other stations, the AM was absent. The concentrations of ammonium at those sites were nearly uniform with depth. Ammonium concentrations in surface waters had large variations (0~72 nmol/L) while small variations (0~25 nmol/L) in waters deeper than 1000 m. Vertically integrated nitrate concentrations in the upper 100 m was 2~3 orders of magnitude higher than nitrite and ammonium inventories. Nitrite inventory generally four times greater than those of ammonium, suggesting more efficient use of reduced nitrogen by micro- and pico-planktons.

  BG11-D3-PM2-P-013 (BG11-A004)
The Effects of Increased Water Flow on Ecohydrology of the Everglades as Observed in Multi-Year Time Series of MODIS Terra NDVI Imagery
Douglas FULLER#+
University of Miami, United States
#Corresponding author: +Presenter

Desiccation of freshwater wetlands can lead to a wide range of ecological changes such as increased oxidation of peat soils and atmospheric CO2 fluxes, invasion of woody plants that do not tolerate flooded conditions, increased frequency of fires, and loss of vertebrates, such as wading birds. Therefore, efforts are underway in many areas to restore water flows that were reduced from wetland drainage efforts designed to reclaim land in the 20th century. In this study, we utilized a 14-year time series (2001-2014) of 8-day composites of the normalized difference vegetation index (NDVI) from the MODIS Terra sensor to study how increased water flows have affected the photosynthetic activity in marshes and tree islands of the Shark River slough (SRS) in the northern portion of Everglades National Park in Florida, USA. Preliminary results showed that increased water flows associated with the removal of a dam-like structure in 2013 increased photosynthetic activity of marsh and prairie plants in the dry season, while the NDVI declined in the wet season most likely due to increased water in each pixel, which may have led to greater absorption of near infrared radiance. While it is too early to discern how increased water flows will affect plant and vertebrate communities, our time series analysis shows the potential of continuous NDVI monitoring as a way to gauge the functional response of a large,  subtropical wetland system to a massive and sudden increase in freshwater inputs.

  BG11-D3-PM2-P-014 (BG11-A008)
Simulating Soil Carbon Dynamics in Alaskan Terrestrial Ecosystems
Xin WANG1#+, Masayuki YOKOZAWA2, Hazuki ARAKIDA3, Kensuke MORI4, Takeshi ISE5, Miyuki KONDO6, Masao UCHIDA6, Keiji KUSHIDA7, Motomu TODA1
1 Hiroshima University, Japan, 2 Shizuoka University, Japan, 3 RIKEN, Japan, 4 University of Calgary, Canada, 5 Kyoto University, Japan, 6 National institute for Environment Studies, Japan, 7 Nihon University, Japan
#Corresponding author: +Presenter

Boreal terrestrial ecosystems act as large reservoir of carbon, most of which is mainly stored in permafrost in the deeper soils. Recently, many observational studies have revealed that ongoing climate warming would stimulate the permafrost thaw and then accelerate soil carbon decomposition rate. Further release of CO2 into the atmosphere from the soil carbon due to increased temperature. That may create a positive feedback in relation to carbon cycle between the atmosphere and boreal terrestrial ecosystems.  In the present study, we examined the effects of increased temperature on soil carbon dynamic change in the typical boreal forest (65°07'24.4"N, 147°29'15.2"W) and tundra (68°54'17"N, 148°52'33"W) sites in Alaska, especially focused on permafrost soil layers by using a Physical and Biogeochemical Soil Dynamics Model (PB-SDM).

In the present study, we conducted a climate warming experiment with an average temperature rise of 4.8° C from 2000 to 2100. The simulated results showed that in year 2000-2100, the amount of SOC in organic layer reduced by 5 kg C m-2 in boreal forest site and 2 kg C m-2 in tundra site, respectively. But, the SOC in mineral layer released by the permafrost thawing was about ten times larger in tundra site than that in boreal forest site due to increased temperature. It is suggested that surface cover condition and soil properties play a dominant role in affecting permafrost thaw. In particular, a thin organic cover can significantly buffer the permafrost against severe degradation.

  BG11-D3-PM2-P-015 (BG11-A011)
Age of the Fossil-Rich Gyeongsang Supergroup in South Korea
Su-Chin CHANG#+
The University of Hong Kong, Hong Kong SAR
#Corresponding author: +Presenter

Abundant fossils have been discovered from the 9000 meter thick Gyeongsang Supergroup in the southern part of the Korean Peninsula. Although most fossils are yet to be well studied, and only few of the fossil occurrences have been published in western journals, the Gyeongsang Supergroup has great potential for substantially increasing our knowledge of Cretaceous terrestrial ecosystems and paleogeography in East Asia. In addition to the body fossils, abundant and well-preserved dinosaur, bird and pterosaur tracks are found from these formations. Well-preserved and extensive vertebrate ichnofaunas from the Gyeongsang Supergroup represent the largest concentration of Cretaceous vertebrate track sites reported from the Asian continent. Furthermore, the stratigraphic frequency of track-bearing levels is greater than that reported for any other region in Asia, and the diversity and abundance of named bird tracks is greater than for any other region. Determining the age of the Gyeongsang Supergroup is critical to understanding several fundamental questions. For examples 1) when did Gyeongsang fauna first appear? 2) Were the Gyeongsang fauna and the Jehol Biota contemporaneous? 3) When did the extensive volcanism occur in this area? 4) Did the frequent volcanic eruptions impact the Gyeongsang ecosystem? In this study, we investigate geological background and establish reliable radioisotopic age for the fossil-rich Gyeongsang Spergroup. 

  BG11-D3-PM2-P-016 (BG11-A012)
A Study on the Distribution Characteristics of Aquatic Ecosystem Health in Nakdong River Basins Based on Spatial Autocorrelation
Myung-hee JO1#, Jun-Seok SIM2, Sung-Hyun JANG3+
1 Kyungpook National University, South Korea, 2 Geo C&I Co., Ltd., Korea, South, South Korea, 3 Geo C&I Co., Ltd., South Korea
#Corresponding author: +Presenter

This study aims to analyze the trends and spatial distribution characteristics of aquatic ecosystem health in the nakdong river basin using the spatial autocorrelation. The distribution characteristics of the riparian habitat and physical-chemical factors that influence aquatic ecosystem are analyzed to provide information about the restoration through the ecological preservation. In situ data acquired between 2011 and 2013 are used to investigate and assess aquatic ecosystem health. In addition, in order to analyze the spatial distribution characteristics of the Nakdong River Basins health, Hotspot (Getis-Ord Gi,) and LISA (Local Indicator of Spatial Association) are utilized. According to the results of hotspot anlaysis for the aquatic ecosystem health of biological index, good health areas are indicated as the hotspot. These areas include the Andong dam, Wangpicheon, Imha dam. Coldspot areas include Nakdong Namhae, Nakdong downstream, Suyoung river basin. The results of LISA analysis are similar to the result of Hotspot analysis. But spatial outliers are shown in Gawha cheon, Hapcheon dam, upper young river. These areas have a high biological health index, but the neighbor areas have a low biological health index. The spatial outliers areas need to be managed. The aquatic ecosystem health data can be used by analytical methods based on spatial information technology. The results of aquatic ecosystems based on the spatial analysis of the health data can be used to provide the information for river basin management.

  BG11-D3-PM2-P-017 (BG11-A014)
Photoassimilated Carbon Allocation and Root Decay in an Intensified Wheat-Soil System Revealed by 14CO2 Pulse Labeling
Zhaoan SUN+, Bo QU, Fanqiao MENG#, Qing CHEN
China Agricultural University, China
#Corresponding author: +Presenter

Intensive farming has being widely adopted in the North China Plain since 1980s to achieve high yield, however little is known about the flows of carbon (C) from winter wheat (Triticum aestivum L.) into belowground and soil organic matter (SOM). A pot experiment on winter wheat by 14CO2 pulse labeling technique, was conducted to quantify the distribution and translocation of the assimilated C from plants to a Calcareous soil. Four growth stages of winter wheat plants (tillering, elongation, anthesis, grain filling) were chosen for pulse labeling with exposure to 14CO2 for 3-hour in each stage. Destructive samplings were applied 5 days after labeling and at the end of growth season. The accumulation of aboveground biomass carbon of winter wheat at elongation and grain filling accounted for 45% and 55% of the total C assimilated over the whole growth cycle respectively. Approximately 25-64% and 2-10% of the 14C present in the winter wheat-soil system were located in the belowground and soil over 5 days period after labeling respectively. At the end of growth season, the proportion of 14C in the belowground and soil accounted for 19-33% and 1-5% of 14C present in the winter wheat-soil system respectively. The respiratory 14C-CO2 losses, calculated as the difference between the total amounts of 14C recovered in the soil-plant system at 5 days and at the end of growth season, accounted for 15-62% of the total 14C fixed. Of the roots formed at the tillering stage, 48% had decayed at the end of crop growth in winter wheat. Since most of the roots were produced around tillering stage, these values were used as estimates of accumulated annual root decay. The data can contribute to a more complete and concise quantification of C management in the North China Plain.

  BG11-D3-PM2-P-018 (BG11-A019)
Biological Organic Carbon Export Estimated from Annual Carbon Budget in the Surface Water of Western Subarctic and Subtropical North Pacific Ocean
Masahide WAKITA1#, Sayaka YASUNAKA1+, Makio HONDA1, Kazuhiko MATSUMOTO1, Tetsuichi FUJIKI1, Hajime KAWAKAMI1, Yoshikazu SASAI2, Chiho SUKIGARA3, Mario UCHIMIYA4, Minoru KITAMURA1, Toru KOBARI5, Yoshihisa MINO3, Akira NAGANO1, Shuichi WATANABE1, Toshiro SAINO1
1 Japan Agency for Marine-Earth Science and Technology, Japan, 2 Frontier Research Center for Global Change, Japan, 3 Nagoya University, Japan, 4 National Institute of Polar Research, Japan, 5 Kagoshima University, Japan
#Corresponding author: +Presenter

The annual flux of biologically produced organic carbon from surface waters is equal to the annual flux of net community production (NCP) at steady state and is exported as particulate and dissolved organic carbon (POC and DOC) to deep water. NCP was estimated from the carbon budget of salinity-normalized dissolved inorganic carbon (nDIC) inventories at two time-series stations in the western subarctic (K2) and subtropical (S1) North Pacific Ocean. By using biogeochemical observations from 2004 to 2013, monthly means of nDIC inventories were integrated from the surface to the annual maximum of the mixed layer depth and corrected for changes due to net air-sea CO2 exchange, net CaCO3 production, vertical diffusion from the upper thermocline, and horizontal advection. The annual organic carbon flux at K2 (~1.5 mol m−2 year−1) was comparable to that at S1 (1.0–2.2 mol m−2 year−1). These fluxes can be classified into three types: POC flux exported vertically (K2: 1.4 mol m–2 yr–1; S1: 0.7–1.9 mol m–2 yr–1) and vertical diffusive fluxes of DOC (K2: 0.03 mol m–2 yr–1; S1: 0.25 mol m–2 yr–1) and suspended POC (K2: 0.03 mol m–2 yr–1; S1: 0.07 mol m–2 yr–1). Estimated export fluxes of POC at K2 and S1 were comparable to the sum of the POC fluxes into sediment traps and active carbon export by migrating zooplankton. The export fluxes were twice those reported at other time-series sites in the eastern subarctic and central subtropics.

  BG11-D3-PM2-P-019 (BG11-A022)
Warming and Human Activity Enhancing Carbon Burial in the Bosten Lake Over the Past 50 Years
Xiujun WANG1,2#+, Zhitong YU3
1 Beijing Normal University, China, 2 University of Maryland, United States, 3 Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, China
#Corresponding author: +Presenter

Lake sediment is an important carbon reservoir that may play a big role in the terrestrial carbon cycle. Bosten Lake is the largest inland freshwater lake in China. In this study, a 22-cm long sediment core was collected from the deepest (14 m) location of the lake in August, 2012. The core was cut into 0.5-cm intervals, and total carbon (TC) and total organic carbon (OC) were measured. We also analyzed isotopic (13C) compositions of OC and inorganic carbon (IC), and 137Cs and 210Pb. Our study showed an increasing trend, with OC accumulation rate from ~10 g C m-2 yr-1 in the 1950s to 30-50 g C m-2 yr-1 in 1990-2012, and IC from ~30 in the 1950s to ~100 in the 1990s. Warming and land use change are largely responsible for the enhancements in carbon burial of the Bosten Lake.

  BG11-D3-PM2-P-020 (BG11-A023)
In Situ Estimation of New and Regenerated Production in Lakes Using Triple Oxygen Isotopes as Tracers
Fumiko NAKAGAWA1#+, Urumu TSUNOGAI1, Daisuke KOMATSU1, Takuya OHYAMA1, Takanori MIYAUCHI1, Makoto UMEDA2, Atsushi TANAKA3
1 Nagoya University, Japan, 2 Tohoku University, Japan, 3 National Institute for Environmental Studies, Japan
#Corresponding author: +Presenter

The gross primary production rate is an essential parameter to study biogeochemical processes in hydrosphere. It is often controlled by supply rates of fixed nitrogen to each hydrospheric environment and often divided into “new production” and “regenerated production” based on nitrogen uptake in the form of NO3- and NH4+, respectively. These parameters had been traditionally estimated based on incubations of sampled water in bottles by adding isotope-labeled compounds. The estimated values, however, corresponds to instantaneous uptake rates when sampling was done and their large errors could be expected for the hydrospheric environments with significant temporal variations.

In this study, we determined the above-mentioned parameters based on the Δ17O value of dissolved O2and NO3- in lake waters instead of using incubation methods. Most of the oxygen-containing molecules on earth show mass-dependent relative variation between 17O/16O ratios and 18O/16O ratios. On the other hand, atmospheric O3 photochemically produced from O2 shows an anomalous enrichment in 17O, so that residual atmospheric O2 becomes slightly depleted in 17O in comparison with the mass-dependent relative relation. Δ17O values of NO3- also deviate from the mass-dependent relative relation, because at least one of the O atoms in atmospheric NO3- is derived from atmospheric O3. Since Δ17O value does not vary during the general mass-dependent reactions such as decompositions, we can estimate the mixing ratio between atmospheric O2 and photosynthetic O2 from Δ17O value of O2 and that between atmospheric NO3- and remineralized NO3- from Δ17O value of NO3-. This leads to determine both the primary production rate and NO3- uptake rate simultaneously. One of the priorities of this Δ17O method is that the estimated rate corresponds to the average value of each instantaneous rate, so that the results can be a more reliable and accurate than those from the incubation methods.