Increased Litterfall in Tropical Forests Boosts the Transfer of Soil CO2 to the Atmosphere

Aboveground litter production in forests is likely to increase as a consequence of elevated atmospheric carbon dioxide (CO2) concentrations, rising temperatures, and shifting rainfall patterns. As litterfall represents a major flux of carbon from vegetation to soil, changes in litter inputs are likely to have wide-reaching consequences for soil carbon dynamics. Such disturbances to the carbon balance may be particularly important in the tropics because tropical forests store almost 30% of the global soil carbon, making them a critical component of the global carbon cycle; nevertheless, the effects of increasing aboveground litter production on belowground carbon dynamics are poorly understood. We used long-term, large-scale monthly litter removal and addition treatments in a lowland tropical forest to assess the consequences of increased litterfall on belowground CO2 production. Over the second to the fifth year of treatments, litter addition increased soil respiration more than litter removal decreased it; soil respiration was on average 20% lower in the litter removal and 43% higher in the litter addition treatment compared to the controls but litter addition did not change microbial biomass. We predicted a 9% increase in soil respiration in the litter addition plots, based on the 20% decrease in the litter removal plots and an 11% reduction due to lower fine root biomass in the litter addition plots. The 43% measured increase in soil respiration was therefore 34% higher than predicted and it is possible that this ‘extra’ CO2 was a result of priming effects, i.e. stimulation of the decomposition of older soil organic matter by the addition of fresh organic matter. Our results show that increases in aboveground litter production as a result of global change have the potential to cause considerable losses of soil carbon to the atmosphere in tropical forests

Beyond literacy and numeracy in patient provider communication: Focus groups suggest roles for empowerment, provider attitude and language

<p>Abstract</p> <p>Background</p> <p>Although the number of people living in the United States with limited English proficiency (LEP) is substantial, the impact of language on patients' experience of provider-patient communication has been little explored.</p> <p>Methods</p> <p>We conducted a series of 12 exploratory focus groups in English, Spanish and Cantonese to elicit discussion about patient-provider communication, particularly with respect to the concerns of the health literacy framework, i.e. ability to accurately understand, interpret and apply information given by providers. Within each language, 2 groups had high education and 2 had low education participants to partially account for literacy levels, which cannot be assessed consistently across three languages. Eighty-five (85) adults enrolled in the focus groups. The resulting video tapes were transcribed, translated and analyzed via content analysis.</p> <p>Results</p> <p>We identified 5 themes: 1) language discordant communication; 2) language concordant communication; 3) empowerment; 4) providers' attitudes; 5) issues with the health care system. Despite efforts by facilitators to elicit responses related to cognitive understanding, issues of interpersonal process were more salient, and respondents did not readily separate issues of accurate understanding from their overall narratives of experience with health care and illness. Thematic codes often appeared to be associated with education level, language and/or culture.</p> <p>Conclusion</p> <p>Our most salient finding was that for most of our participants there was no clear demarcation between literacy and numeracy, language interpretation, health communication, interpersonal relations with their provider and the rest of their experience with the health care system.</p

Soil Respiration in Relation to Photosynthesis of Quercus mongolica Trees at Elevated CO2

Knowledge of soil respiration and photosynthesis under elevated CO2 is crucial for exactly understanding and predicting the carbon balance in forest ecosystems in a rapid CO2-enriched world. Quercus mongolica Fischer ex Ledebour seedlings were planted in open-top chambers exposed to elevated CO2 (EC = 500 µmol mol−1) and ambient CO2 (AC = 370 µmol mol−1) from 2005 to 2008. Daily, seasonal and inter-annual variations in soil respiration and photosynthetic assimilation were measured during 2007 and 2008 growing seasons. EC significantly stimulated the daytime soil respiration by 24.5% (322.4 at EC vs. 259.0 mg CO2 m−2 hr−1 at AC) in 2007 and 21.0% (281.2 at EC vs. 232.6 mg CO2 m−2 hr−1 at AC) in 2008, and increased the daytime CO2 assimilation by 28.8% (624.1 at EC vs. 484.6 mg CO2 m−2 hr−1 at AC) across the two growing seasons. The temporal variation in soil respiration was positively correlated with the aboveground photosynthesis, soil temperature, and soil water content at both EC and AC. EC did not affect the temperature sensitivity of soil respiration. The increased daytime soil respiration at EC resulted mainly from the increased aboveground photosynthesis. The present study indicates that increases in CO2 fixation of plants in a CO2-rich world will rapidly return to the atmosphere by increased soil respiration

Light and Heavy Fractions of Soil Organic Matter in Response to Climate Warming and Increased Precipitation in a Temperate Steppe

Soil is one of the most important carbon (C) and nitrogen (N) pools and plays a crucial role in ecosystem C and N cycling. Climate change profoundly affects soil C and N storage via changing C and N inputs and outputs. However, the influences of climate warming and changing precipitation regime on labile and recalcitrant fractions of soil organic C and N remain unclear. Here, we investigated soil labile and recalcitrant C and N under 6 years' treatments of experimental warming and increased precipitation in a temperate steppe in Northern China. We measured soil light fraction C (LFC) and N (LFN), microbial biomass C (MBC) and N (MBN), dissolved organic C (DOC) and heavy fraction C (HFC) and N (HFN). The results showed that increased precipitation significantly stimulated soil LFC and LFN by 16.1% and 18.5%, respectively, and increased LFC∶HFC ratio and LFN∶HFN ratio, suggesting that increased precipitation transferred more soil organic carbon into the quick-decayed carbon pool. Experimental warming reduced soil labile C (LFC, MBC, and DOC). In contrast, soil heavy fraction C and N, and total C and N were not significantly impacted by increased precipitation or warming. Soil labile C significantly correlated with gross ecosystem productivity, ecosystem respiration and soil respiration, but not with soil moisture and temperature, suggesting that biotic processes rather than abiotic factors determine variations in soil labile C. Our results indicate that certain soil carbon fraction is sensitive to climate change in the temperate steppe, which may in turn impact ecosystem carbon fluxes in response and feedback to climate change

Climate and species affect fine root production with long-term fertilization in acidic tussock tundra near Toolik Lake, Alaska

Author Posting. © The Author(s), 2007. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Oecologia 153 (2007): 643-652, doi:10.1007/s00442-007-0753-8.Long-term fertilization of acidic tussock tundra has led to changes in plant species composition, increases in aboveground production and biomass and substantial losses of soil organic carbon (SOC). Root litter is an important input to SOC pools, though little is known about fine root demography in tussock tundra. In this study, we examined the response of fine root production and live standing fine root biomass to short- and long-term fertilization, as changes in fine root demography may contribute to observed declines in SOC. Live standing fine root biomass increased with long-term fertilization, while fine root production declined, reflecting replacement of the annual fine root system of Eriophorum vaginatum, with the long-lived fine roots of Betula nana. Fine root production increased in fertilized plots during an unusually warm growing season, but remained unchanged in control plots, consistent with observations that B. nana shows a positive response to climate warming. Calculations based on a few simple assumptions suggest changes in fine root demography with long-term fertilization and species replacement could account for between 20 and 39% of observed declines in SOC stocks.This project was supported by National Science Foundation research grants 9810222, 9911681, 0221606 and 0528748

Improving healthcare empowerment through breast cancer patient navigation: a mixed methods evaluation in a safety-net setting

BACKGROUND: Breast cancer mortality rates in the U.S. remain relatively high, particularly among ethnic minorities and low-income populations. Unequal access to quality care, lower follow up rates, and poor treatment adherence contribute to rising disparities among these groups. Healthcare empowerment (HCE) is theorized to improve patient outcomes through collaboration with providers and improving understanding of and compliance with treatment. Patient navigation is a health care organizational intervention that essentially improves healthcare empowerment by providing informational, emotional, and psychosocial support. Patient navigators address barriers to care through multilingual coordination of treatment and incorporation of access to community services, support, and education into the continuum of cancer care. METHODS: Utilizing survey and qualitative methods, we evaluated the patient navigation program in a Northern California safety-net hospital Breast Clinic by assessing its impact on patients’ experiences with cancer care and providers’ perspectives on the program. We conducted qualitative interviews with 16 patients and 4 service providers, conducted approximately 66 hours of clinic observations, and received feedback through the self-administered survey from 66 patients. RESULTS: The role of the patient navigator at the Breast Clinic included providing administrative assistance, psychosocial support, improved knowledge, better understanding of treatment process, and ensuring better communication between patients and providers. As such, patient navigators facilitated improved collaboration between patients and providers and understanding of interdisciplinary care processes. The survey results suggested that the majority of patients across all ethnic backgrounds and age groups were highly satisfied with the program and had a positive perception of their navigator. Interviews with patients and providers highlighted the roles of a navigator in ensuring continuity of care, improving treatment completion rates, and reducing providers’ workload and waiting time. Uncertainty about the navigator’s role among the patients was a weakness of the program. CONCLUSIONS: Patient navigation in the Breast Clinic had a positive impact on patients’ experiences with care and healthcare empowerment. Clarifying uncertainties about the navigators’ role would aid successful outcomes