Activation of Methanogenesis in Arid Biological Soil Crusts Despite the Presence of Oxygen

Methanogenesis is traditionally thought to occur only in highly reduced, anoxic environments. Wetland and rice field soils are well known sources for atmospheric methane, while aerated soils are considered sinks. Although methanogens have been detected in low numbers in some aerated, and even in desert soils, it remains unclear whether they are active under natural oxic conditions, such as in biological soil crusts (BSCs) of arid regions. To answer this question we carried out a factorial experiment using microcosms under simulated natural conditions. The BSC on top of an arid soil was incubated under moist conditions in all possible combinations of flooding and drainage, light and dark, air and nitrogen headspace. In the light, oxygen was produced by photosynthesis. Methane production was detected in all microcosms, but rates were much lower when oxygen was present. In addition, the δ13C of the methane differed between the oxic/oxygenic and anoxic microcosms. While under anoxic conditions methane was mainly produced from acetate, it was almost entirely produced from H2/CO2 under oxic/oxygenic conditions. Only two genera of methanogens were identified in the BSC-Methanosarcina and Methanocella; their abundance and activity in transcribing the mcrA gene (coding for methyl-CoM reductase) was higher under anoxic than oxic/oxygenic conditions, respectively. Both methanogens also actively transcribed the oxygen detoxifying gene catalase. Since methanotrophs were not detectable in the BSC, all the methane produced was released into the atmosphere. Our findings point to a formerly unknown participation of desert soils in the global methane cycle

Relationship-centered Care: A Constructive Reframing

All illness, care, and healing processes occur in relationship—relationships of an individual with self and with others. Relationship-centered care (RCC) is an important framework for conceptualizing health care, recognizing that the nature and the quality of relationships are central to health care and the broader health care delivery system. RCC can be defined as care in which all participants appreciate the importance of their relationships with one another. RCC is founded upon 4 principles: (1) that relationships in health care ought to include the personhood of the participants, (2) that affect and emotion are important components of these relationships, (3) that all health care relationships occur in the context of reciprocal influence, and (4) that the formation and maintenance of genuine relationships in health care is morally valuable. In RCC, relationships between patients and clinicians remain central, although the relationships of clinicians with themselves, with each other and with community are also emphasized