Automated Monitoring of Soil Respiration: an Improved Automatic Chamber System

We designed, constructed and tested an automated chamber system for continuously monitoring soil respiration. Our objective was to design a system that would permit monitoring of CO2 efflux rates over long time periods without altering microclimate inside the chamber. The measuring principle is based on the measurement of the increase in CO2 concentration within an automated chamber in a fixed amount of time using a non linear regression method. The chamber operates by closing over the soil in response to a control signal and remains closed for a fixed amount of time. In this way, the chamber allows normal drying and wetting of the soil between measurements. We report results that show the reliability of soil CO2 efflux measurements in comparison with Li-Cor 6400. The system holds great potential for long term continuous measurements campaigns in natural environments

Assessing the contribution of beach-cast seagrass wrack to global GHGs emissions: experimental models, problems and perspectives

6openopenGloria Misson, Guido Incerti, Giorgio Alberti, Gemini Delle Vedove, Tiziana Pirelli, Alessandro PeressottiMisson, Gloria; Incerti, Guido; Giorgio, Alberti; Gemini Delle Vedove, ; Tiziana, Pirelli; Alessandro, Peressott

Carbon Dynamics in younger Stands of Pedunculate Oak during two Vegetation Periods

U radu je procijenjena neto produktivnost ekosustava (NEP) i neto bilanca ugljika (NECB) u mladoj sastojini hrasta lužnjaka (Quercus roburL.) pomoću dvije neovisne metode i to: a) mikrometeorološke metode vrtložne kovarijance (EC) te, b) kombinirane metode koja je uključivala biometrijsku izmjeru šumske biomase i periodičko mjerenje respiracije tla (SR). Maksimalni NEP zabilježen vrtložnom kovarijancom iznosio je 10,7 gC m-2 dan-1u 2008.godine, odnosno 12,2 gC m-2dan-1u 2009. godini. Godišnje vrijednosti NEP kretale su se od 384 gC m-2god-1u 2008. do 584 gC m-2god-1u 2009. Godini,iz čega je razvidno da su sastojine u dohvatu mjerne stanice u obje godine bile neto spremnik ugljika. Biometrijskom metodom praćenja prirasta i produkcije listinca i sitnog drvnog otpada dobivenaje neto primarna produktivnost (NPP)od 777 gC m-2 god-1u 2008.godine, odnosno 846 gC m-2god-1u 2009. godini. Udio heterotrofne respiracije (Rh) procijenjen je na 50% od izmjerene ukupne SR, pa je Rh procijenjena na 438 gC m-2god-1u 2008.godini, odnosno 441 gC m-2god-1u 2009. godini. Kombiniranom metodom NEP je dobivena kao razlika NPP i Rh, a iznosila je 339 i 405 gC m-2god-1u 2008.godini, odnosno 2009. godini. Usporedba dvaju metoda procjene NEP-a daje dobro slaganje do srpnja za obje promatrane godine. Do odstupanja dolazi u drugom dijelu ljeta i jeseni kada prestaje debljinski prirast, ali stabla očito i dalje aktivno spremaju ugljik. Kombinirana metoda daje manje vrijednosti NEP-a u odnosu na metodu vrtložne kovarijance, iz više razloga npr.: udio Rh je manji od 50 %, omjer podzemnog i nadzemnog dijela biomase; R:S je veći od 0,257,i sl. Potrebna su daljnja istraživanja koja bi empirički odredila udio Rhu SR, omjer R:S te istraživanja količine ugljika u sastavnicama tla.Net Ecosystem Productivity (NEP) and Net Ecosystem Carbon Balance (NECB) of young Pedunculate oak (Quercus roburL.) stand were investigated. Two independent methods for assessing NEP were used: a) micrometeorological method of Eddy covariance (EC) and, b) combination of biometric method for assessing Net Primary Productivity (NPP) and periodic soil respiration (SR) measurements (named for reasons of brevity the combined method). NEP from combined method was obtained as a difference of NPP and heterotrophic respiration (Rh) which was estimated to have 50% share in the measured total SR. Maximal measured daily NEP from eddy covariance was 10,7 gC m-2 day-1in 2008., and 12,2 gC m-2day-1in 2009. The annual NEP ranged from 384 gC m-2yr-1in 2008 to584 gC m-2yr-1in 2009 indicating that the stands around the EC tower were actively storing carbon during both years. From biometric measurements of stem increment using dendrometer bands, height increment and litter production we obtained an average NPP of the stands in the footprint of 777 gC m-2yr-1in 2008 and 846 gC m-2yr-1in 2009. Heterotrophic respiration (Rh) , estimated from SR measurements was 438 gC m-2yr-1in 2008 and 441 gC m-2yr-1in 2009. By subtracting Rhfrom NPP, we obtained NEP of 339 and 405 gC m-2yr-1in 2008 and 2009, respectively. Comparison of results for NEP during vegetation season reveals that agreement between the two methods was very good until July for both years. Later in the summer and autumn, discrepancy occurs when stem growth ceases but trees continue to actively store carbon. This leads to the underestimation of NEP from combined method during that period, leading to the overall lower values of NEP when compared with NEP values from eddy covariance. There could be several reasons for the discrepancies namely, share of Rhin total SR could be less than 50 %, R:S could be higher than 0.257, or various combinations of both. Further research is needed that would provide better estimates of share of Rhin SR, R:S ratio and soil carbon content

Carbon Dynamics in younger Stands of Pedunculate Oak during two Vegetation Periods

U radu je procijenjena neto produktivnost ekosustava (NEP) i neto bilanca ugljika (NECB) u mladoj sastojini hrasta lužnjaka (Quercus roburL.) pomoću dvije neovisne metode i to: a) mikrometeorološke metode vrtložne kovarijance (EC) te, b) kombinirane metode koja je uključivala biometrijsku izmjeru šumske biomase i periodičko mjerenje respiracije tla (SR). Maksimalni NEP zabilježen vrtložnom kovarijancom iznosio je 10,7 gC m-2 dan-1u 2008.godine, odnosno 12,2 gC m-2dan-1u 2009. godini. Godišnje vrijednosti NEP kretale su se od 384 gC m-2god-1u 2008. do 584 gC m-2god-1u 2009. Godini,iz čega je razvidno da su sastojine u dohvatu mjerne stanice u obje godine bile neto spremnik ugljika. Biometrijskom metodom praćenja prirasta i produkcije listinca i sitnog drvnog otpada dobivenaje neto primarna produktivnost (NPP)od 777 gC m-2 god-1u 2008.godine, odnosno 846 gC m-2god-1u 2009. godini. Udio heterotrofne respiracije (Rh) procijenjen je na 50% od izmjerene ukupne SR, pa je Rh procijenjena na 438 gC m-2god-1u 2008.godini, odnosno 441 gC m-2god-1u 2009. godini. Kombiniranom metodom NEP je dobivena kao razlika NPP i Rh, a iznosila je 339 i 405 gC m-2god-1u 2008.godini, odnosno 2009. godini. Usporedba dvaju metoda procjene NEP-a daje dobro slaganje do srpnja za obje promatrane godine. Do odstupanja dolazi u drugom dijelu ljeta i jeseni kada prestaje debljinski prirast, ali stabla očito i dalje aktivno spremaju ugljik. Kombinirana metoda daje manje vrijednosti NEP-a u odnosu na metodu vrtložne kovarijance, iz više razloga npr.: udio Rh je manji od 50 %, omjer podzemnog i nadzemnog dijela biomase; R:S je veći od 0,257,i sl. Potrebna su daljnja istraživanja koja bi empirički odredila udio Rhu SR, omjer R:S te istraživanja količine ugljika u sastavnicama tla.Net Ecosystem Productivity (NEP) and Net Ecosystem Carbon Balance (NECB) of young Pedunculate oak (Quercus roburL.) stand were investigated. Two independent methods for assessing NEP were used: a) micrometeorological method of Eddy covariance (EC) and, b) combination of biometric method for assessing Net Primary Productivity (NPP) and periodic soil respiration (SR) measurements (named for reasons of brevity the combined method). NEP from combined method was obtained as a difference of NPP and heterotrophic respiration (Rh) which was estimated to have 50% share in the measured total SR. Maximal measured daily NEP from eddy covariance was 10,7 gC m-2 day-1in 2008., and 12,2 gC m-2day-1in 2009. The annual NEP ranged from 384 gC m-2yr-1in 2008 to584 gC m-2yr-1in 2009 indicating that the stands around the EC tower were actively storing carbon during both years. From biometric measurements of stem increment using dendrometer bands, height increment and litter production we obtained an average NPP of the stands in the footprint of 777 gC m-2yr-1in 2008 and 846 gC m-2yr-1in 2009. Heterotrophic respiration (Rh) , estimated from SR measurements was 438 gC m-2yr-1in 2008 and 441 gC m-2yr-1in 2009. By subtracting Rhfrom NPP, we obtained NEP of 339 and 405 gC m-2yr-1in 2008 and 2009, respectively. Comparison of results for NEP during vegetation season reveals that agreement between the two methods was very good until July for both years. Later in the summer and autumn, discrepancy occurs when stem growth ceases but trees continue to actively store carbon. This leads to the underestimation of NEP from combined method during that period, leading to the overall lower values of NEP when compared with NEP values from eddy covariance. There could be several reasons for the discrepancies namely, share of Rhin total SR could be less than 50 %, R:S could be higher than 0.257, or various combinations of both. Further research is needed that would provide better estimates of share of Rhin SR, R:S ratio and soil carbon content

Eddy covariance vs. biometric based estimates of net primary productivity of Pedunculate Oak (Quercus robur L.) forest in Croatia during ten years

We analysed 10 years (2008⁻2017) of continuous eddy covariance (EC) CO2 flux measurements of net ecosystem exchange (NEE) in a young pedunculate oak forest in Croatia. Measured NEE was gap-filled and partitioned into gross primary productivity (GPP) and ecosystem reparation (RECO) using the online tool by Max Planck Institute for Biogeochemistry in Jena, Germany. Annual NEE, GPP, and RECO were correlated with main environmental drivers. Net primary productivity was estimated from EC (NPPEC), as a sum of −NEE and Rh obtained using a constant Rh:RECO ratio, and from independent periodic biometric measurements (NPPBM). For comparing the NPP at the seasonal level, we propose a simple model that aimed at accounting for late-summer and autumn carbon storage in the non-structural carbohydrate pool. Over the study period, Jastrebarsko forest acted as a carbon sink, with an average (±std. dev.) annual NEE of −319 (±94) gC m−2 year−1, GPP of 1594 (±109) gC m−2 year−1, and RECO of 1275 (±94) gC m−2 year−1. Annual NEE showed high inter-annual variability and poor correlation with annual average global radiation, air temperature, and total precipitation, but significant (R2 = 0.501, p = 0.02) correlation with the change in soil water content between May and September. Comparison of annual NPPEC and NPPBM showed a good overall agreement (R2 = 0.463, p = 0.03), although in all years NPPBM was lower than NPPEC, with averages of 680 (±88) gC m−2 year−1 and 819 (±89) gC m−2 year−1, respectively. Lower values of NPPBM indicate that fine roots and grasses contributions to NPP, which were not measured in the study period, could have an important contribution to the overall ecosystem NPP. At a seasonal level, two NPP estimates showed differences in their dynamic, but the application of the proposed model greatly improved the agreement in the second part of the growing season. Further research is needed on the respiration partitioning and mechanisms of carbon allocation

Local Stategies for Land Management according to Kyoto Protocol. Exploring New Management Tools for Co2 Sequestration in Agricultuural Lands and Forests.

he Kyoto Protocol promotes and encourages new strategies for land manage-ment oriented to carbon sequestration and greenhouse gases removal. In or-der to make these strategies the most effective, a large scale implementation at local, regional and national level is requested. Therefore administrative au-thorities responsible for land management shall individualize these strategies and operates for planning choices in coherence with the aims of Kyoto Protocol. Within this frame European regions can play a new role, not already foreseen in the ac-tual Kyoto commitments and strategies, but desirable for the development of new ap-proaches evolving from the bottom up. If so, supported by the scientific community, Re-gions could test small-scale policy experiments at the local level so to contribute to com-bat climate change and adapt to its unavoidable consequences, and at the same time to allow local population to benefit directly of the environmental policies. The Carbon-Pro project supplies public authorities responsible for land planning with useful and easily suitable tools for transferring some concepts of the Kyoto Protocol and carbon sequestration into local and regional land planning strategies. This is also the meaning of the Agreement on local management strategies for Carbon sequestration, signed in Lubljana within Carbon-Pro and focused on the creation of local carbon markets

Kinematic Evidence of Root-to-Shoot Signaling for the Coding of Support Thickness in Pea Plants

Plants such as climbers characterized by stems or tendrils need to find a potential support (e.g., pole, stick, other plants or trees) to reach greater light exposure. Since the time when Darwin carried out research on climbing plants, several studies on plants’ searching and attachment behaviors have demonstrated their unique ability to process some features of a support to modulate their movements accordingly. Nevertheless, the strategies underlying this ability have yet to be uncovered. The present research tries to fill this gap by investigating how the interaction between above- (i.e., stems, tendrils, …) and below-ground (i.e., the root system) plant organs influences the kinematics of their approach-to-grasp movements. Using three-dimensional (3D) kinematic analysis, we characterized the movements of pea plants (Pisum sativum L.) as they leaned towards supports whose below- and above-ground parts were characterized by different thicknesses (i.e., thin below- thick above-ground, or the opposite). As a control condition, the plants were placed next to supports with the same thickness below and above ground (i.e., either entirely thin or thick). The results suggest that the information regarding below- and above-ground parts of a support appears to be integrated and modulates the reach-to-grasp behavior of the plant. Information about the support conveyed by the root system seems to be particularly important to achieve the end-goal of movement