scholarly journals Vertical profiles of leaf photosynthesis and leaf traits and soil nutrients in two tropical rainforests in French Guiana before and after a 3-year nitrogen and phosphorus addition experiment

2022 ◽  
Vol 14 (1) ◽  
pp. 5-18
Author(s):  
Lore T. Verryckt ◽  
Sara Vicca ◽  
Leandro Van Langenhove ◽  
Clément Stahl ◽  
Dolores Asensio ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Large Scale ◽  
French Guiana ◽  
Photosynthetic Capacity ◽  
Leaf Traits ◽  
Environmental Drivers ◽  
Nutrient Cycle ◽  
Tropical Rainforests ◽  
Vertical Profiles ◽  
Nitrogen And Phosphorus

Abstract. Terrestrial biosphere models typically use the biochemical model of Farquhar, von Caemmerer, and Berry (1980) to simulate photosynthesis, which requires accurate values of photosynthetic capacity of different biomes. However, data on tropical forests are sparse and highly variable due to the high species diversity, and it is still highly uncertain how these tropical forests respond to nutrient limitation in terms of C uptake. Tropical forests often grow on soils low in phosphorus (P) and are, in general, assumed to be P rather than nitrogen (N) limited. However, the relevance of P as a control of photosynthetic capacity is still debated. Here, we provide a comprehensive dataset of vertical profiles of photosynthetic capacity and important leaf traits, including leaf N and P concentrations, from two 3-year, large-scale nutrient addition experiments conducted in two tropical rainforests in French Guiana. These data present a unique source of information to further improve model representations of the roles of N, P, and other leaf nutrients in photosynthesis in tropical forests. To further facilitate the use of our data in syntheses and model studies, we provide an elaborate list of ancillary data, including important soil properties and nutrients, along with the leaf data. As environmental drivers are key to improve our understanding of carbon (C) and nutrient cycle interactions, this comprehensive dataset will aid to further enhance our understanding of how nutrient availability interacts with C uptake in tropical forests. The data are available at https://doi.org/10.5281/zenodo.5638236 (Verryckt, 2021).

scholarly journals Vertical profiles of leaf photosynthesis and leaf traits, and soil nutrients in two tropical rainforests in French Guiana before and after a three-year nitrogen and phosphorus addition experiment

2021 ◽  
Author(s):  
Lore Talle Verryckt ◽  
Sara Vicca ◽  
Leandro Van Langenhove ◽  
Clément Stahl ◽  
Dolores Asensio ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Large Scale ◽  
French Guiana ◽  
Photosynthetic Capacity ◽  
Leaf Traits ◽  
Environmental Drivers ◽  
Nutrient Cycle ◽  
Tropical Rainforests ◽  
Vertical Profiles ◽  
Nitrogen And Phosphorus

Abstract. Terrestrial biosphere models typically use the biochemical model of Farquhar, von Caemmerer and Berry (1980) to simulate photosynthesis, which requires accurate values of photosynthetic capacity of different biomes. However, data on tropical forests are sparse and highly variable due to the high species diversity, and it is still highly uncertain how these tropical forests respond to nutrient limitation in terms of C uptake. Tropical forests often grow on phosphorus (P)-poor soils and are, in general, assumed to be P- rather than nitrogen (N)-limited. However, the relevance of P as a control of photosynthetic capacity is still debated. Here, we provide a comprehensive dataset of vertical profiles of photosynthetic capacity and important leaf traits, including leaf N and P concentrations, from two three-year, large-scale nutrient addition experiments conducted in two tropical rainforests in French Guiana. These data present a unique source of information to further improve model representations of the roles of N, P, and other leaf nutrients, in photosynthesis in tropical forests. To further facilitate the use of our data in syntheses and model studies, we provide an elaborate list of ancillary data, including important soil properties and nutrients, along with the leaf data. As environmental drivers are key to improve our understanding of carbon (C)-nutrient cycle interactions, this comprehensive dataset will aid to further enhance our understanding of how nutrient availability interacts with C uptake in tropical forests. The data are available at DOI 10.5281/zenodo.4719242 (Verryckt, 2021).

scholarly journals A new model of the coupled carbon, nitrogen, and phosphorus cycles in the terrestrial biosphere (QUINCY v1.0; revision 1996)

2019 ◽  
Vol 12 (11) ◽  
pp. 4781-4802 ◽  
Author(s):  
Tea Thum ◽  
Silvia Caldararu ◽  
Jan Engel ◽  
Melanie Kern ◽  
Marleen Pallandt ◽  
...  
Keyword(s):  
Large Scale ◽  
Terrestrial Ecosystems ◽  
Ecosystem Dynamics ◽  
Nutrient Cycle ◽  
Monitoring Networks ◽  
Nitrogen And Phosphorus ◽  
Terrestrial Biosphere ◽  
Seamless Integration ◽  
New Model ◽  
Terrestrial Ecosystem Model

Abstract. The dynamics of terrestrial ecosystems are shaped by the coupled cycles of carbon, nitrogen, and phosphorus, and these cycles are strongly dependent on the availability of water and energy. These interactions shape future terrestrial biosphere responses to global change. Here, we present a new terrestrial ecosystem model, QUINCY (QUantifying Interactions between terrestrial Nutrient CYcles and the climate system), which has been designed from scratch to allow for a seamless integration of the fully coupled carbon, nitrogen, and phosphorus cycles with each other and also with processes affecting the energy and water balances in terrestrial ecosystems. This new model includes (i) a representation of plant growth which separates source (e.g. photosynthesis) and sink (growth rate of individual tissues, constrained by temperature and the availability of water and nutrients) processes; (ii) the acclimation of many ecophysiological processes to meteorological conditions and/or nutrient availability; (iii) an explicit representation of vertical soil processes to separate litter and soil organic matter dynamics; (iv) a range of new diagnostics (leaf chlorophyll content; 13C, 14C, and 15N isotope tracers) to allow for a more in-depth model evaluation. In this paper, we present the model structure and provide an assessment of its performance against a range of observations from global-scale ecosystem monitoring networks. We demonstrate that QUINCY v1.0 is capable of simulating ecosystem dynamics across a wide climate gradient, as well as across different plant functional types. We further provide an assessment of the sensitivity of key model predictions to the model's parameterisation. This work lays the ground for future studies to test individual process hypotheses using the QUINCY v1.0 framework in the light of ecosystem manipulation observations, as well as global applications to investigate the large-scale consequences of nutrient-cycle interactions for projections of terrestrial biosphere dynamics.

scholarly journals Leaf Nutrient Relations of Cycads in a Common Garden

2021 ◽  
Vol 14 ◽  
pp. 194008292110365
Author(s):  
Thomas E. Marler ◽  
Anders J. Lindström
Keyword(s):  
Common Garden ◽  
Nutrient Content ◽  
Leaf Traits ◽  
Botanical Garden ◽  
Active Management ◽  
Nitrogen And Phosphorus ◽  
Representative Species ◽  
Nutrient Relations ◽  
Homogeneous Environment ◽  
Dry Combustion

Background and Aims Research required to clarify leaf nutrient relations of cycad species has been inadequate. Common garden studies are useful for determining the influence of genetics on leaf traits because of the homogeneous environment among experimental units. To date, there have been no common garden studies which included all ten genera of cycads. The full phylogenetic breadth has, therefore, not been included in this important area of study. Methods We examined macronutrient and micronutrient content of leaves from one representative species from each of the ten cycad genera at Nong Nooch Tropical Botanical Garden in Thailand. Nitrogen content was determined by dry combustion, and the remaining nutrients were quantified by spectrometry. Results The least variable elements were nitrogen and phosphorus, and the most variable elements were boron and sodium. Nutrient content based on leaflet area was more variable than based on leaflet mass, reflecting species differences in specific leaf area. There were no universal macronutrient or micronutrient signals indicating clear phylogenetic distinctions. Implications for Conservation: Active management of threatened cycad taxa requires research to develop the knowledge to enable evidence-based decisions. This common garden study inclusive of all 10 cycad genera creates a foundation to determine leaf nutrient sufficiency ranges to inform management decisions.

scholarly journals Characteristic Study of Briquette Cyanobacteria as Fuel in Chemical Looping Combustion with Hematite as Oxygen Carrier

2021 ◽  
Vol 11 (10) ◽  
pp. 4388
Author(s):  
Haifeng Zhang ◽  
Laihong Shen ◽  
Huijun Ge ◽  
Hongcun Bai
Keyword(s):  
Large Scale ◽  
Oxygen Carrier ◽  
Compressive Load ◽  
Phosphorus Recovery ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Carbon Conversion ◽  
Nitrogen And Phosphorus ◽  
Liquid Products ◽  
Lower Temperature

Due to the more and more serious cyanobacteria bloom problem, it is particularly urgent to find a technology suitable for large-scale disposal and the efficient recovery of abundant nitrogen and phosphorus resources in cyanobacteria. The combination of chemical looping combustion (CLC) and biomass densification technology is thought to be a promising utilization selection. Based on the experimental results, the mechanical strength and energy density of briquette cyanobacteria are evidently increased with the compressive load; whereas, 10% is the optimal moisture content in the densification process. A higher heating rate in TGA would result in the damage of the internal structure of the briquette cyanobacteria, which are conducive to the carbon conversion efficiency. The presence of a hematite oxygen carrier would enhance the carbon conversion and catalyzed crack liquid products. CO2 yield is increased 25 percent and CH4 yield is decreased 50 percent at 900 °C in the CLC process. In addition, the lower temperature and reduction atmosphere in CLC would result in a lower NO emission concentration. The reactivity and porous property of hematite OC in CLC also increased during 10 redox cycle experiments. The CLC process accelerates the generation of CaH2P2O7 and CaHPO4 in cyanobacteria ash, which is more conducive to phosphorus recovery.

Risk Factors for a Positive Hepatitis C Status in Fishermen in Kuantan Malaysia

2019 ◽  
Vol 31 (3) ◽  
pp. 227-237
Author(s):  
Priya Lall ◽  
Rumana Saifi ◽  
Diva Baggio ◽  
Samantha Fitzsimmons Schoenberger ◽  
Martin Choo ◽  
...  
Keyword(s):  
Hepatitis C ◽  
Confidence Interval ◽  
Risk Taking ◽  
Odds Ratio ◽  
Large Scale ◽  
Adjusted Odds Ratio ◽  
Environmental Drivers ◽  
Negative Effects ◽  
Risk Taking Behaviors ◽  
Risk Communities

Malaysia currently has an estimated hepatitis C virus (HCV) prevalence of 1.3% with an infected population of 384,000. Fishermen in Malaysia are at risk of HCV infection due to injection drug use and disproportionately high rates of incarceration. This study used quantitative data from Project WAVES, a large-scale mixed methods project charting environmental drivers of risk-taking behaviors among a respondent-driven sample of 406 fishermen in Malaysia. Over a quarter of participants (27.9%) reported injecting drugs in the past month; 49.8% of the sample tested positive for HCV. Respondents who had previously been arrested displayed increased odds of being HCV-positive (adjusted odds ratio = 4.79, confidence Interval = 2.46-9.35). Participants who reported being in lock-up displayed close to 6-fold odds of being HCV-infected (adjusted odds ratio = 5.49, confidence interval = 2.77-10.90, P < .001). These findings underscore the need for policies and structural interventions targeting the negative effects of aggressive incarceration contributing to the burden of HCV among high-risk communities.

scholarly journals Lianas reduce carbon accumulation and storage in tropical forests

2015 ◽  
Vol 112 (43) ◽  
pp. 13267-13271 ◽  
Author(s):  
Geertje M. F. van der Heijden ◽  
Jennifer S. Powers ◽  
Stefan A. Schnitzer
Keyword(s):  
Tropical Forests ◽  
Large Scale ◽  
Net Primary Production ◽  
Carbon Dynamics ◽  
Carbon Accumulation ◽  
Carbon Uptake ◽  
Woody Vines ◽  
Significant Difference ◽  
Agent Of Change ◽  
The Impact

Tropical forests store vast quantities of carbon, account for one-third of the carbon fixed by photosynthesis, and are a major sink in the global carbon cycle. Recent evidence suggests that competition between lianas (woody vines) and trees may reduce forest-wide carbon uptake; however, estimates of the impact of lianas on carbon dynamics of tropical forests are crucially lacking. Here we used a large-scale liana removal experiment and found that, at 3 y after liana removal, lianas reduced net above-ground carbon uptake (growth and recruitment minus mortality) by ∼76% per year, mostly by reducing tree growth. The loss of carbon uptake due to liana-induced mortality was four times greater in the control plots in which lianas were present, but high variation among plots prevented a significant difference among the treatments. Lianas altered how aboveground carbon was stored. In forests where lianas were present, the partitioning of forest aboveground net primary production was dominated by leaves (53.2%, compared with 39.2% in liana-free forests) at the expense of woody stems (from 28.9%, compared with 43.9%), resulting in a more rapid return of fixed carbon to the atmosphere. After 3 y of experimental liana removal, our results clearly demonstrate large differences in carbon cycling between forests with and without lianas. Combined with the recently reported increases in liana abundance, these results indicate that lianas are an important and increasing agent of change in the carbon dynamics of tropical forests.

scholarly journals Climate engineering and the ocean: effects on biogeochemistry and primary production

2017 ◽  
Author(s):  
Siv K. Lauvset ◽  
Jerry Tjiputra ◽  
Helene Muri
Keyword(s):  
Primary Production ◽  
Radiative Forcing ◽  
Large Scale ◽  
Stratospheric Aerosol ◽  
Climate Impacts ◽  
Environmental Drivers ◽  
Earth System ◽  
Climate Engineering ◽  
Mean Sea Surface ◽  
Radiation Management

Abstract. Here we use an Earth System Model with interactive biogeochemistry to project future ocean biogeochemistry impacts from large-scale deployment of three different radiation management (RM) climate engineering (also known as geoengineering) methods: stratospheric aerosol injection (SAI), marine sky brightening (MSB), and cirrus cloud thinning (CCT). We apply RM such that the change in radiative forcing in the RCP8.5 emission scenario is reduced to the change in radiative forcing in the RCP4.5 scenario. The resulting global mean sea surface temperatures in the RM experiments are comparable to those in RCP4.5, but there are regional differences. The forcing from MSB, for example, is applied over the oceans, so the cooling of the ocean is in some regions stronger for this method of RM than for the others. Changes in ocean primary production are much more variable, but SAI and MSB give a global decrease comparable to RCP4.5 (~ 6 % in 2100 relative to 1971–2000), while CCT give a much smaller global decrease of ~ 3 %. The spatially inhomogeneous changes in ocean primary production are partly linked to how the different RM methods affect the drivers of primary production (incoming radiation, temperature, availability of nutrients, and phytoplankton) in the model. The results of this work underscores the complexity of climate impacts on primary production, and highlights that changes are driven by an integrated effect of multiple environmental drivers, which all change in different ways. These results stress the uncertain changes to ocean productivity in the future and advocates caution at any deliberate attempt for large-scale perturbation of the Earth system.

scholarly journals Nuisance growth ofJuncus bulbosus: the roles of genetics and environmental drivers tested in a large-scale survey

2012 ◽  
Vol 58 (1) ◽  
pp. 114-127 ◽  
Author(s):  
THERESE F. MOE ◽  
ANNE K. BRYSTING ◽  
TOM ANDERSEN ◽  
SUSANNE C. SCHNEIDER ◽  
ØYVIND KASTE ◽  
...  
Keyword(s):  
Large Scale ◽  
Environmental Drivers ◽  
Large Scale Survey

In-cloud scavenging scheme for sectional aerosol modules – implementation in the framework of the Sectional Aerosol module for Large Scale Applications version 2.0 (SALSA2.0) global aerosol module

2021 ◽  
Author(s):  
Eemeli Holopainen ◽  
Harri Kokkola ◽  
Anton Laakso ◽  
Thomas Kühn
Keyword(s):  
Wet Deposition ◽  
Large Scale ◽  
Climate Model ◽  
Radiation Budget ◽  
Cloud Formation ◽  
The Arctic ◽  
Vertical Profiles ◽  
Size Classes ◽  
Aerosol Emission ◽  
Aerosol Module

&lt;p&gt;&lt;span&gt;Black carbon (BC) affects the radiation budget of the Earth by absorbing solar radiation, darkening snow and ice covers, and influencing cloud formation and life cycle. Modelling BC in remote regions, such as the Arctic, has large inter-model variability which causes variation in the modelled aerosol effect over the Arctic. This variability can be due to differences in the transport of aerosol species which is affected by how wet deposition is modelled. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt; In this study we developed an aerosol size-resolved in-cloud wet deposition scheme for liquid and ice clouds for models which use a size-segregated aerosol description. This scheme was tested in the ECHAM-HAMMOZ global aerosol-climate model. The scheme was compared to the original wet deposition scheme which uses fixed scavenging coefficients for different sized particles. The comparison included vertical profiles and mass and number wet deposition fluxes, and it showed that the current scheme produced spuriously long BC lifetimes when compared to the estimates made in other studies. Thus, to find a better setup for simulating aerosol lifetimes and vertical profiles we conducted simulations where we altered the aerosol emission distribution and hygroscopicity.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt; We compared the modelled BC vertical profiles to the ATom aircraft campaign measurements. In addition, we compared the aerosol lifetimes against those from AEROCOM model means. We found that, without further tuning, the current scheme overestimates the BC concentrations and lifetimes more than the fixed scavenging scheme when compared to the measurements. Sensitivity studies showed that the model skill of reproducing the measured vertical BC mass concentrations improved when BC emissions were directed to larger size classes, they were mixed with soluble compounds during emission, or BC-containing particles were transferred to soluble size classes after aging. These changes also produced atmospheric BC lifetimes which were closer to AEROCOM model means. The best comparison with the measured vertical profiles and estimated BC lifetimes was when BC was mixed with soluble aerosol compounds during emission.&lt;/span&gt;&lt;/p&gt;

Site-level soil moisture controls water-use efficiency improvement and climate response in sugar maple: a dual dendroisotopic study

2021 ◽  
pp. 1-12
Author(s):  
R. Dietrich ◽  
F.W. Bell ◽  
M. Anand
Keyword(s):  
Soil Moisture ◽  
Water Use Efficiency ◽  
Water Use ◽  
Tree Ring ◽  
Sugar Maple ◽  
Photosynthetic Capacity ◽  
Environmental Drivers ◽  
Tree Level ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Given the large contribution of forests to terrestrial carbon storage, there is a need to resolve the environmental and physiological drivers of tree-level response to rising atmospheric CO2. This study examines how site-level soil moisture influences growth and intrinsic water-use efficiency in sugar maple (Acer saccharum Marsh.). We construct tree-ring, δ18O, and Δ13C chronologies for trees across a soil moisture gradient in Ontario, Canada, and employ a structural equation modelling approach to ascertain their climatic, ontogenetic, and environmental drivers. Our results support previous evidence for the presence of strong developmental effects in tree-ring isotopic chronologies — in the range of −4.7‰ for Δ13C and +0.8‰ for δ18O — across the tree life span. Additionally, we show that the physiological response of sugar maple to increasing atmospheric CO2 depends on site-level soil moisture variability, with trees only in relatively wet plots exhibiting temporal increases in intrinsic water-use efficiency. These results suggest that trees in wet and mesic plots have experienced temporal increases in stomatal conductance and photosynthetic capacity, whereas trees in dry plots have experienced decreases in photosynthetic capacity. This study is the first to examine sugar maple physiology using a dendroisotopic approach and broadens our understanding of carbon–water interactions in temperate forests.

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