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A Brief History of Nutritional Medicine and the Emergence of Nutrition as a Medical Subspecialty
Published in Michael M. Rothkopf, Jennifer C. Johnson, Optimizing Metabolic Status for the Hospitalized Patient, 2023
Michael M. Rothkopf, Jennifer C. Johnson
The concept of a nitrogen cycle was emerging. It envisioned that nitrogen was extracted from the air by specific plants which were later eaten by animals who excreted nitrogen back into the soil to be used by other plants as a fertilizer.
Pufferfish Aquariums
Published in Ramasamy Santhanam, Biology and Ecology of Toxic Pufferfish, 2017
Nitrogen cycle: It is the basic process of biological filtration in the aquarium. Ammonia is one of the key elements in the nitrogen cycle. Fish produce ammonia directly both as a by-product of respiration and as a waste product from the digestion of foods. Solid wastes are also converted into ammonia. It is therefore important to remove these solid wastes through mechanical filtration. Uneaten food, plant materials, and other organic items that decay in the tank are also converted to ammonia. This ammonia, a nitrogen-based compound, is extremely toxic. In any aquarium, it can build up quickly and threaten all the fish in the tank. The bacteria already accumulated in the gravel bed of the aquarium help in this regard. Nitrosomonas sp. will first act upon the ammonia (in the presence of dissolved oxygen) and convert the same into nitrite, a toxic compound. This compound in the long run tends to be a larger problem than ammonia. Subsequently another species of bacteria viz. Nitrobacter sp. converts it into nitrate, a relatively harmless compound that can be used up by plants and algae.
Policy Strategies for Reducing the Climate Impact of Food and Agriculture
Published in Joyce D’Silva, John Webster, The Meat Crisis, 2017
Stefan Wirsenius, Fredrik Hedenus, David Bryngelsson
These rather limited technological potentials are related to the fact that these methane and nitrous oxide emissions occur due to intrinsic characteristics of the systems. The digestive system of ruminants inevitably involves production of methane at significant levels that cannot be drastically reduced without fundamentally manipulating the digestive process. Similarly, nitrous oxide production is an inherent part of the nitrogen cycle, and a high nitrogen turnover per land area – which is required for medium to high crop yields – inevitably entails production and release of significant amounts of nitrous oxide.
Analysis of marine microbial communities colonizing various metallic materials and rust layers
Published in Biofouling, 2019
Yimeng Zhang, Yan Ma, Jizhou Duan, Xiaohong Li, Jing Wang, Baorong Hou
In case of the archaea, Candidatus nitrosopumilus belonging to the Thaumarchaeota, dominated the archaeal communities in seawater, in the sea mud and on all three metal surfaces, even on the toxic copper surface (Table 2). Members of this genus grow chemolithoautotrophically by aerobically oxidizing ammonia to nitrite (Könneke et al. 2005) and have high specific affinity for reduced nitrogen which ensures that they successfully compete with heterotrophic bacterioplankton and phytoplankton (Martens-Habbena et al. 2009). Thus they are widespread in the marine environment with a high abundance, contributing to the marine nitrogen cycle. Previous studies have shown that bacteria contribute mostly to surface colonization, while archaea are seldomly detected (Dang et al. 2008, Webster and Negri 2006). However, archaeal members were determined in all samples from metal surfaces in the present study. Their role in metal surface colonization should be revaluated.