Biosphere-atmosphere exchange of NOx in the tropical mangrove forest
TL;DR: In this paper, the Sundarban mangrove forest along the northeast coast of the Bay of Bengal, India, showed uptake rate of −0.84 to −1.63 ng N m−2 s−1 during the day and both uptake and emission rates of − 0.36 to 5.19 ng Nm−2 S−1 in the night from September to February.
Abstract: [1] Biosphere-atmosphere exchange of NOx at the Sundarban mangrove forest along the northeast coast of the Bay of Bengal, India, showed uptake rates of −0.84 to −1.63 ng N m−2 s−1 during the day and both uptake and emission rates of −0.36 to 5.19 ng N m−2 s−1 during the night from September to February. However, during the period from March to August, NOx emission ranged between 0.34 and 2.13 ng N m−2 s−1 and 0.88 and 3.26 ng N m−2 s−1 in daytime and nighttime, respectively. During the postmonsoon period, NOx uptake could be attributed to mangrove stomatal activity during the day. Mangroves absorbed nitrogen from both the soil and the atmosphere. Seasonal and diurnal variability of NOx and O3 is partly due to plant growth in the postmonsoon period. In addition to the NOx-O3 photochemical cycle, stomatal uptake of NOx could also be an important process for keeping a low-ozone state at the land-ocean boundary of the northeast coast of the Bay of Bengal.
Citations
More filters
TL;DR: In this paper, the authors used a box model approach to assess the nitrogen budget in the Sundarban mangrove ecosystem, which acts as a sink for atmospheric nitrogen in terms of NOx, NH3, N2, and water column dissolved inorganic nitrogen.
56 citations
TL;DR: In this article, the distribution and exchange fluxes of methane (CH4) were measured in a mangrove vegetated island and its bordering estuarine system of the Sundarbans biosphere from June 2010 to December 2011 on monthly basis.
47 citations
TL;DR: In this paper, a ship-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements were performed within the SHIVA campaign on board RV Sonne in the South China and Sulu Sea.
35 citations
TL;DR: In this paper, the capacity of world's largest mangrove, the Sundarbans (Indian part) to sequester anthropogenic CO 2 emitted from the proximate coal-based thermal power plant in Kolaghat (∼100 km away from mangroves site).
34 citations
TL;DR: In this article, the relative changes in present level of reservoirs organic carbon contents in response to the future increase of atmospheric carbon dioxide were examined in the Avicennia-dominated mangrove forest at the land-ocean boundary of the northeast coast of the Bay of Bengal.
Abstract: Because of the difficulties in setting up arrangements in the intertidal zone for free-air carbon dioxide enrichment experimentation, the responses to increasing atmospheric carbon dioxide in mangrove forests are poorly studied. This study applied box model to overcome this limitation, and the relative changes in present level of reservoirs organic carbon contents in response to the future increase of atmospheric carbon dioxide were examined in the Avicennia- dominated mangrove forest at the land–ocean boundary of the northeast coast of the Bay of Bengal. The above- and below-ground biomass (AGB+BGB) and sediment held different carbon stock (53.20±2.87Mg C ha −1 (mega gram carbon per hectare) versus 18.52±2.77Mg C ha −1 ). Carbon uptake (0.348mg C m −2 s −1 ) is more than offset by losses from plant emission (0.257mg C m −2 s −1 ), and litter fall (13.52µg C m −2 s −1 ) was more than soil CO 2 and CH 4 emission (8.36 and 1.39µg C m −2 s −1 , respectively). Across inventory plots, Sundarban mangrove forest carbon storage in above- and below-ground live trees and soil increased by 18.89 and 5.94Mg C ha −1 between June 2009 and December 2011. Box model well predicted the dynamics of above- and below-ground biomass and soil organic carbon, and increasing atmospheric carbon dioxide concentrations could be the cause of 1.1- and 1.57-fold increases in carbon storage in live biomass and soil, respectively, across Sundarban mangrove forest rather than recovery from past disturbances. Keywords: carbon stock, CO 2 sensitivity, box model, mangrove forest, India (Published: 23 April 2013) Citation: Tellus B 2013, 65 , 18981, http://dx.doi.org/10.3402/tellusb.v65i0.18981
33 citations
References
More filters
TL;DR: In this article, a chamber technique was used to study the uptake of NO and NO 2 by branches of Scots pine trees at concentrations ranging from about I ppbv (ambient levels) up to about 50 pbv.
Abstract: A chamber technique was used to study the uptake of NO and NO 2 by branches of Scots Pine trees at concentrations ranging from about I ppbv (ambient levels) up to about 50 ppbv. The measurements were performed under field conditions of light intensity and temperature. Rates of photosynthesis and transpiration were determined from continuous measurements of CO 2 and water vapour. The uptake of NO was small at all concentrations. The deposition rate per projected needle area was less than 0.1 mm s -l . For NO 2 , the uptake varied linearly with concentration. At high levels, the uptake was limited both by a stomata1 and an internal resistance and a marked diurnal variation was observed. Typical deposition rates per projected needle area at concentrations larger than 10 ppbv were 1-2 mm s -l during the day and 0.05-0.2 mm s -l during the night. The internal resistance constituted between 3% and 60% of the total resistance to NO 2 uptake. Contrary to observations made at high concentrations, no uptake of NO 2 could be detected when the concentration was decreased to 1 to 3 ppbv. Using a leaf area index of 3 m 2 m -2 , which is a typical value for a pine forest in Sweden, a deposition velocity per ground area of < 1 mm s -l is obtained. This is significantly lower than other values reported in the literature. Since the NO 2 concentration in the atmosphere of large rural areas covered with coniferous forest is of the same order of magnitude as that where no uptake of NO 2 was observed, this finding is of great importance for modelling of atmospheric chemistry and transport in the boundary layer. A comparison with the uptake of SO 2 and O 3 shows that daytime deposition velocities for these gases are a factor 10 larger than those for NO 2 . DOI: 10.1111/j.1600-0889.1987.tb00204.x
94 citations
TL;DR: The photodissociation rate of NO 2 by sunlight, j NO 2, has been measured as a function of solar zenith angle, χ, at a nonurban field site in the Colorado mountains under a variety of sky conditions as discussed by the authors.
80 citations
TL;DR: In this article, the effect of N2O5 hydrolysis on sulfate aerosols on NOx and O3 budgets in the Tropospheric Ozone Production about the Spring Equinox (TOPSE) was investigated.
Abstract: [1] The distributions of NOx and O3 are analyzed during TOPSE (Tropospheric Ozone Production about the Spring Equinox). In this study these data are compared with the calculations of a global chemical/transport model (Model for OZone And Related chemical Tracers (MOZART)). Specifically, the effect that hydrolysis of N2O5 on sulfate aerosols has on tropospheric NOx and O3 budgets is studied. The results show that without this heterogeneous reaction, the model significantly overestimates NOx concentrations at high latitudes of the Northern Hemisphere (NH) in winter and spring in comparison to the observations during TOPSE; with this reaction, modeled NOx concentrations are close to the measured values. This comparison provides evidence that the hydrolysis of N2O5 on sulfate aerosol plays an important role in controlling the tropospheric NOx and O3 budgets. The calculated reduction of NOx attributed to this reaction is 80 to 90% in winter at high latitudes over North America. Because of the reduction of NOx, O3 concentrations are also decreased. The maximum O3 reduction occurs in spring although the maximum NOx reduction occurs in winter when photochemical O3 production is relatively low. The uncertainties related to uptake coefficient and aerosol loading in the model is analyzed. The analysis indicates that the changes in NOx due to these uncertainties are much smaller than the impact of hydrolysis of N2O5 on sulfate aerosol. The effect that hydrolysis of N2O5 on global NOx and O3 budgets are also assessed by the model. The results suggest that in the Northern Hemisphere, the average NOx budget decreases 50% due to this reaction in winter and 5% in summer. The average O3 budget is reduced by 8% in winter and 6% in summer. In the Southern Hemisphere (SH), the sulfate aerosol loading is significantly smaller than in the Northern Hemisphere. As a result, sulfate aerosol has little impact on NOx and O3 budgets of the Southern Hemisphere.
75 citations
TL;DR: In this article, the effect of NO 2 fumigation on root N uptake and metabolism was investigated in 3-month-old spruce (Picea abies L. Karst) seedlings.
Abstract: The effect of NO 2 fumigation on root N uptake and metabolism was investigated in 3-month-old spruce (Picea abies L. Karst) seedlings. In a first experiment, the contribution of NO 2 to the plant N budget was measured during a 48h fumigation with 100 mm 3 m -3 NO 2 . Plants were pretreated with various nutrient solutions containing NO 3 - and NH 4 + , NO 3 - only or no nitrogen source for 1 week prior to the beginning of fumigation. Absence of NH 4 + in the solution for 6 d led to an increased capacity for NO 3 - uptake, whereas the absence of both ions caused a decrease in the plant N concentration, with no change in NO 3 - uptake. In fumigated plants, NO 2 uptake accounted for 20-40% of NO 3 - uptake. Root NO 3 - uptake in plants supplied with NH 4 + plus NO 3 - solutions was decreased by NO 2 fumigation, whereas it was not significantly altered in the other treatments. In a second experiment, spruce seedlings were grown on a solution containing both NO 3 - and NH 4 + and were fumigated or not with 100 mm 3 m -3 NO 2 for 7 weeks. Fumigated plants accumulated less dry matter, especially in the roots. Fluxes of the two N species were estimated from their accumulations in shoots and roots, xylem exudate analysis and 15 N labelling. Root NH 4 + uptake was approximately three times higher than NO 3 - uptake. Nitrogen dioxide uptake represented 10-15% of the total N budget of the plants. In control plants, N assimilation occurred mainly in the roots and organic nitrogen was the main form of N transported to the shoot. Phloem transport of organic nitrogen accounted for 17% of its xylem transport. In fumigated plants, neither NO 3 - nor NH 4 + accumulated in the shoot, showing that all the absorbed NO 2 was assimilated. Root NO 3 - reduction was reduced whereas organic nitrogen transport in the phloem increased by a factor of 3 in NO 2 -fumigated as compared with control plants. The significance of the results for the regulation of whole-plant N utilization is discussed.
69 citations
TL;DR: The pasture was found to be a net sink for nitrogen in the form of NOx, and Corrections made to NO and NO2 fluxes to compensate for chemical reactions showed flux divergences of the order of 30%, but these were not statistically significantly different from the measured fluxes.
67 citations