Editing Plankton (section)

=== Humans and plankton ===
Plankton have many direct and indirect effects on humans.

Around 70% of the oxygen in the atmosphere is produced in the oceans from [[phytoplankton]] performing photosynthesis, meaning that the majority of the oxygen available for us and other organisms that [[Cellular respiration#Aerobic respiration|respire aerobically]] is produced by plankton.<ref>{{Cite journal |last1=Sekerci |first1=Yadigar |last2=Petrovskii |first2=Sergei |date=2015-12-01 |title=Mathematical Modelling of Plankton–Oxygen Dynamics Under the Climate Change |url=https://doi.org/10.1007/s11538-015-0126-0 |journal=Bulletin of Mathematical Biology |language=en |volume=77 |issue=12 |pages=2325–2353 |doi=10.1007/s11538-015-0126-0 |pmid=26607949 |s2cid=8637912 |issn=1522-9602|hdl=2381/36058 |hdl-access=free }}</ref>

Plankton also make up the base of the marine food web, providing food for all the trophic levels above. Recent studies have analyzed the marine food web to see if the system runs on a [[Top-down and bottom-up design|top-down or bottom-up approach]]. Essentially, this research is focused on understanding whether changes in the food web are driven by nutrients at the bottom of the food web or predators at the top. The general conclusion is that the bottom-up approach seemed to be more predictive of food web behavior.<ref>{{Cite journal |last1=Frederiksen |first1=Morten |last2=Edwards |first2=Martin |last3=Richardson |first3=Anthony J. |last4=Halliday |first4=Nicholas C. |last5=Wanless |first5=Sarah |date=November 2006 |title=From plankton to top predators: bottom-up control of a marine food web across four trophic levels |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2656.2006.01148.x |journal=Journal of Animal Ecology |language=en |volume=75 |issue=6 |pages=1259–1268 |doi=10.1111/j.1365-2656.2006.01148.x |pmid=17032358 |bibcode=2006JAnEc..75.1259F |issn=0021-8790}}</ref> This indicates that plankton have more sway in determining the success of the primary consumer species that prey on them than do the secondary consumers that prey on the primary consumers.

In some cases, plankton act as an intermediate [[Host (biology)|host]] for deadly parasites in humans. One such&nbsp;case is that of [[cholera]], an infection caused by several pathogenic strains of ''[[Vibrio cholerae]]''. These species have been shown to have a symbiotic relationship with chitinous zooplankton species like [[copepod]]s. These bacteria benefit not only from the food provided by the chiton from the zooplankton, but also from the protection from acidic environments. Once the copepods have been ingested by a human host, the chitinous exterior protects the bacteria from the stomach acids in the stomach and proceed to the intestines. Once there, the bacteria bind with the surface of the small intestine and the host will start developing symptoms, including extreme diarrhea, within five days.<ref>{{Cite journal |last1=Lipp |first1=Erin K. |author-link1 = Erin Lipp|last2=Huq |first2=Anwar |last3=Colwell |first3=Rita R. |date=October 2002 |title=Effects of Global Climate on Infectious Disease: the Cholera Model |journal=Clinical Microbiology Reviews |language=en |volume=15 |issue=4 |pages=757–770 |doi=10.1128/CMR.15.4.757-770.2002 |issn=0893-8512 |pmc=126864 |pmid=12364378 }}</ref>