Editing Adélie penguin (section)

===Osmoregulation===
Adélie penguins are faced with extreme [[osmotic]] conditions, as their frozen habitats offer little fresh water. Such desert conditions mean that the vast majority of the available water is highly saline, causing the diets of Adélie penguins to be heavy in salt.<ref name="Cite1">{{cite journal|last1=Janes|first1=Donald|title=Osmoregulation by Adélie Penguin Chicks on the Antarctic Peninsula|journal=The Auk|date=1997|volume=114|issue=3|pages=488–95|doi=10.2307/4089249|jstor=4089249|doi-access=free}}</ref> They manage to circumvent this problem by eating krill with internal concentrations of salt at the lower end of their possible concentrations, helping to lower the amount of ingested salts.<ref name="Cite1" /> The amount of sodium imposed by this sort of diet is still relatively heavy and can create complications when considering the less tolerant chicks. Adult Adélie penguins feed their chicks by regurgitating the predigested krill, which can impose an excessive salt intake on the chicks. Adult birds address this problem by altering the ion concentrations while the food is still being held in their stomachs. By removing a portion of the sodium and potassium ions, adult Adélie penguins protect their chicks from ingesting excessive amounts of sodium.<ref name="Cite1" /> Adélie penguins also manage their salt intake by concentrating [[cloaca]]l fluids to a much higher degree than most other birds are capable. This ability is present regardless of ontogeny in Adélie penguins, meaning that both adults and juveniles are capable of withstanding extreme levels of salt ion concentration.<ref name="Cite1" /> However, chicks do possess a greater ability to concentrate chloride ions in their cloacal fluids.<ref name="Cite1" /> [[Salt gland]]s also play a major role in the excretion of excess salts. In aquatic birds such as the Adelie penguin, nasal salt glands excrete an extremely concentrated sodium chloride solution, reducing the load on their kidneys.<ref name="Cite2">{{cite journal|last1=Schmidt-Nielsen|first1=Knut|title=The Salt-Secreting Gland of Marine Birds|journal=Circulation|date=1980|volume=21|issue=5|pages=955–67|doi=10.1161/01.cir.21.5.955|pmid=14443123|doi-access=free}}</ref>

These excretions are crucial in the maintenance of Antarctic ecosystems. Penguin [[rookeries]] can be home to thousands of penguins, all of which are concentrating waste products in their digestive tracts and nasal glands.<ref name="Cite4">{{cite journal|last1=Andrzej|first1=Myrcha|last2=Anderzej|first2=Tatur|title=Ecological Role of the Current and Abandoned Penguin Rookeries in the Land Environment of the Maritime Antarctic|journal=Polish Polar Research|date=1991|volume=12|issue=1|pages=3–24}}</ref> These excretions inevitably drop to the ground. The concentration of salts and nitrogenous wastes helps to facilitate the flow of material from the sea to the land, serving to make it habitable for bacteria which live in the soils.<ref name="Cite4" />

[[File:Adelie Penguins on iceberg.jpg|thumbnail|left|In Antarctica|alt=On an iceberg in Antarctica]]