Gallagher, J.B.; Chew, S.-T.; Madin, J., and Thorhaug, A., 2020. Valuing carbon stocks across a tropical lagoon after accounting for black and inorganic carbon: Bulk density proxies for monitoring. Journal of Coastal Research, 36(5), 1029–1039. Coconut Creek (Florida), ISSN 0749-0208. Total organic carbon (TOC) stocks of seagrass and mangroves across a Southeast Asian lagoon were measured and valued after correcting for black carbon (BC) and calcareous carbon equivalents (PICequiv) in mitigating CO2 emissions, along with sediment dry bulk densities (DBDs), as a cost-effective means of estimating carbon stock concepts. Overall, seagrass and mangrove TOC densities ranged from 15.3 ± 4.3 and 124.3 ± 21.1 Mg C ha–1, respectively, across the lower lagoon and 175.2 ± 46.9 and 103.2 ± 19.0 Mg C ha–1 for seagrass and 355.0 ± 24.8 and 350.3 ± 35.2 Mg C ha–1 for mangroves across the two upper lagoon branches. Only mangrove biomass made significant additional contributions, ranging from 178.5 ± 62.3 to 120.7 ± 94.8 Mg C ha–1 for lower and upper regions, respectively. The difference between the lagoon's seagrass and mangrove TOC total stock (5.98 ± 0.69 and 390 ± 33.22 Gg C, respectively) was further amplified by the larger mangrove area. When corrected for BC and PICequiv, the carbon stock mitigation service was reduced by a moderate 14.2%. Across the lagoon the sedimentary DBD showed strong (R2 = 0.85, p < 0.001) to moderate (R2 = 0.67, p < 0.001) linear correlations with seagrass and mangrove [TOC], respectively and moderate correlations with seagrass [PIC] (R2 = 0.6, p < 0.001). There was an invariant and relatively constant response to mangrove [PIC] (2.7 ± 0.07 kg m–3). Valuations were worth on average US$0.44 million y–1 over 20 years, and less than the total income of the indigenous custodians (US$1.8 and US$7.4 million y–1). [ABSTRACT FROM AUTHOR]
UECKER, TED M., KASPARI, SUSAN D., MUSSELMAN, KEITH N., and SKILES, S. MCKENZIE
Journal of Hydrometeorology. Aug2020, Vol. 21 Issue 8, p1777-1792. 16p.
WILDFIRE prevention, CARBON-black, SOOT, WATER supply, SNOW, CLIMATE change models, and FOREST canopies
Wildfires in the snow zone affect ablation by removing forest canopy, which enhances surface solar irradiance, and depositing light absorbing particles [LAPs, such as black carbon (BC)] on the snowpack, reducing snow albedo. How variations in BC deposition affects post-wildfire snowmelt timing is poorly known and highly relevant to water resources. We present a field-based analysis of BC variability across five sites of varying burn age and burn severity in the Cascade Range, Washington State, United States. Single particle soot photometer (SP2) analyses of BC snow concentrations were used to assess the impact of BC on snow albedo, and radiative transfer modeling was used to estimate the radiative effect of BC on snowmelt. Results were compared to Snowpack Telemetry (SNOTEL) data from one site that burned in 2012 and another in a proximal unburned forest. We show that post-wildfire forests provide a significant source of BC to the snowpack, and this effect increases by an order of magnitude in regions of high versus low burn severity, and decreased by two orders of magnitude over a decade. There is a shift in the timing of snowmelt, with snow disappearance occurring on average 196 9 days earlier post-wildfire (2013-19) relative to pre-wildfire (1983-2012). This study improves understanding of the connection between wildfire activity and snowmelt, which is of high relevance as climate change models project further decreases in snowpack and increases in wildfire activity in the Washington Cascades. [ABSTRACT FROM AUTHOR]
Natural rubber (NR) composites filled with carbon nanotubes (CNT), and carbon black (CB) were prepared. Also, other rubber matrices were tested, namely epoxidized-NR (ENR) and isoprene rubber (IR). The aim was to examine the effects of polarity and non-rubber constituents in rubber on mechanical and piezoresistive sensor properties. Thus, the relative resistances during extension were determined under static (stepwise) and dynamic (cycling) deformation of the composites. It was found that ENR-CNT/CB exhibited mechanical properties superior to NR-CNT/CB and IR-CNT/CB. This is attributed to the chemical ENR-CNT/CB linkages and physical interactions of non-rubber components with CNT/CB surfaces. This also helps the recovery of resistivity to the original value after 20 extension cycles. After 10 000 cycles, the resistivity had changed by 2 orders of magnitude before showing the constant resistivity. Thus, ENR-CNT/CB composites can serve in sensors for health monitoring, motion sensors, and other related products, being cost-effective and easy-to-process materials. [ABSTRACT FROM AUTHOR]
This study aimed to investigate the working hazards and health problems among rubber farmers in the southern part of Thailand. A cross-sectional survey questionnaire was employed to identify the workers' working hazards and health problems, workers' postures, and the measurement of the intensity of light, lung function, and eye vision. Results indicated that 45.5 % of the rubber farmers were exposed to a chemical substance, 87 % were exposed to a scorpion, and 27.6 % had a high job strain. Furthermore, 43.8 % of the rubber farmers had a high ergonomic risk when collecting the rubber latex. However, the intensity of the headlamp had met the standard. Findings also revealed some common health problems among rubber farmers. These were musculoskeletal disorders (87.7 %), depression symptoms (15.7 %), and hand eczema (8.9 %). Additionally, nearly half of the Thai rubber farmers had an accident at work (45.1 %, while 22 % reported to have bitten by a poisonous animal. Lastly, 78.4 % of the rubber farmers had a low level of visual requirement and half of them had an abnormal lung function (57.2 %). These findings suggest a need for work process modifications to prevent health hazard in Thai rubber farmers. [ABSTRACT FROM AUTHOR]
The effect of thermally induced crystallization of high-cis polybutadiene (BR) on dynamic mechanical spectra is analyzed under different heating and cooling conditions. It is studied how the addition of carbon black and the blending with styrene-butadiene rubber (SBR) and natural rubber (NR) is affecting the crystallization. For unfilled BR an increased heating rate after fast cooling delivers less crystallization demonstrating that crystal formation requires time. With rising carbon black (CB) loading, a pronounced increase of crystallization speed is found indicating that CB supports nucleation and growth of BR crystals. In BR/SBR blends, which are detected as a single phase in dynamic mechanical spectra, crystallization is reduced for low SBR amounts and seems to disappear totally for 50/50 blends. In blends of BR, SBR, and NR the filler distribution is determined by comparing the peak heights in the loss modulus G? of unfilled and filled compounds. The filler located in each phase is determined from the increase of the peak height corresponding to the respective phase. It is found that the filler is mainly located in the NR phase. [ABSTRACT FROM AUTHOR]