User:Elivernois3/sandbox

Article evaluation

The nitrogen cycle article seems to be well written. The article addresses all parts of the nitrogen cycle and is fairly comprehensible. There are many links to other wikipedia articles and the article doesn't go into too much detail about subjects that are probably covered in those articles. I was a little confused about why there was a separate section on the marine part of the nitrogen cycle. That section did not seem as well organized as the rest of the article and I am not sure that section is necessary because the steps of the nitrogen cycle take place in marine areas as well as terrestrial ones. In general the article seems to be fairly neutral. The section on the human influences on the nitrogen cycle is especially good at focusing on quantifiable facts. The section on the consequences of human modification of the nitrogen cycle have a point of view, but seem to be showing provable facts and not opinions. The article seemed to be fairly well sourced. Every link that I clicked on worked, and most of the citations were for review articles which are considered good sources for wikipedia.

The calcium cycle article seems to contain mostly relevant information about the cycle of calcium without many gaps, but the organization of the article makes the relationship between the ideas confusing. There isn't a clear structure which makes the flow of the cycle obvious, and there are a few sections that seem to talk about the relationship between people and the calcium cycle, but they are not grouped together. I also was a little confused by the figure showing the carbonate cycle, I didn't feel like that material was covered in the text and the images in that section really interrupt the flow of the article. There are some key links to other wikipedia articles where appropriate, which is good. In general the article seems to be fairly neutral. There were a few sections, especially the industrial use of calcium, and importance of calcium and future predictions sections near the end, where the article was presenting things in a factual tone, but the facts were connected to humans and climate change and so seemed to be making an argument, and these sections were not as well cited as the rest of the article. The last section in particular had an entire paragraph with no citations. When there were enough sources, the sources seemed pretty good. All but one of the links that I clicked on worked, however there were several links to original research and the link that didn't work looked like it went to a private company, so it's not clear that the sources are as neutral as they could be.

The iron cycle article seems to contain good information about the cycle of iron, but it had less information about the iron cycle, especially the steps of iron cycling than some of the other cycle articles did. The structure of the article was straightforward, and there weren't any sections that overlapped or repeated. I thought that it was alright that the marine and terrestrial sections were separated, but I felt like each section individually could have used a little more detail about the cycling of iron in those environments, and not just its importance. Some of the information about cycling was in the introduction section and I feel like some of those details could have been moved to later sections since the information wasn't elaborated on. I liked that there was a section about the geological history of the iron cycle, but again I wish there were more information about the processes of the cycling. There are links to other wikipedia articles but it doesn't seem like it is linked to the major articles describing steps of iron cycling in a systematic way, so it isn't obvious where one would look to see elaboration on the chemistry of the individual processes. This article seems very neutral. The links I clicked on all worked. The references are sometimes to original research so that is not perfect, and a few times I looked at the citation it wasn't immediately obvious that the source shared that exact fact, because the paper was focused on something a little different and the fact was just a small part of the paper.

The figure in the iron cycling article is pretty high quality. It is readable and the image makes sense. The different regions are clearly labeled and there are arrows showing the flow of material, but it feels a little busy. I wish that the processes were labeled with a different size font than the estimated fluxes, and that there was a more clear difference between processes in the cycle and states that the iron can be in, but that might be a little nit picky. To the best of my knowledge, the figure is scientifically accurate, and the units are very clear.

Article Draft:

Biogeochemical zinc cycle. Zinc fluxes between the lithosphere and biosphere, through basins in soil, biomass, water systems, and industry. Estimated fluxes are shown as labeled arrows in Gg/year.

The zinc cycle is the biogeochemical cycle that transports zinc through the lithosphere, hydrosphere, and biosphere.

Natural Zinc Cycle

The zinc cycle has historically been characterized by episodic changes in zinc deposits. Major global events such as the formation or breakup of supercontinents and periods of significant volcanic activity tend to create new deposits of zinc in the lithosphere. In between these events, zinc tends to cycle through the biosphere at a lower rate of change.

Zinc minerals in the earths crust exist primarily as sulfides, such as sphalerite and wurtzite, and carbonates such as smithsonite. Because zinc is not only present in carbonate minerals but is also an essential nutrient the zinc cycle is linked to both the sulfur cycle and the carbon cycle. Zinc minerals enter the terrestrial environment through weathering and human activities. Zinc is either used by plants and other organisms or it enters aquatic systems where it either settles into sediments or eventually enter the oceans.

Zinc is a significant marine micronutrient which, as a heavy metal, tends to be in higher concentration in the deep ocean and is transformed into organic zinc which enters the food chain by diatoms blooms during upwelling events in the Southern Ocean. Some marine zinc settles to the ocean floor such that marine sediments in ocean trenches contain an average of 86 ppm of zinc and it is estimated that 112 Gg of zinc flux into the mantle from the subduction of ocean trenches.

Anthropogenic Influence

The anthropogenic effect on the zinc cycle has been significant. Zinc is mined as a mineral resource used by humans at a rate of 9800 Gg/yr for use in metal alloys including brass and nickel silver, for galvanizing steel, and in zinc compounds such as zinc oxide. Half of zinc waste from industrial use is from tailings and slag released in the production of zinc, the rest comes from the oxidation of zinc metals and landfill waste. Scientists estimate that 85% of all zinc that has been mined for human use is still in use, so the amount of zinc waste going into landfills is expected to increase. Zinc is a trace nutrient present in fertilizers, which contribute to 21 Gg/yr of the zinc in crops. Commercial fertilizers contain as much as 36% zinc. Only a small portion of the zinc which enters the agricultural system is removed in crops that are consumed by humans, a significant portion is recycled in manure and compost and accumulates in the soil.