Editing Antarctic krill (section)

===Decline with shrinking pack ice===
[[File:Krillicekils.gif|thumb|Temperature and pack ice area over time, after data compiled by Loeb ''et al.'' 1997.<ref name="L+97">{{cite journal |author1=V. Loeb |author2=V. Siegel |author3=O. Holm-Hansen |author4=R. Hewitt |author5=W. Fraser |author6=W. Trivelpiece |author7=S. Trivelpiece |year=1997 |title=Effects of sea-ice extent and krill or salp dominance on the Antarctic food web |journal=[[Nature (journal)|Nature]] |volume=387 |issue=6636 |pages=897–900 |doi=10.1038/43174 |url=http://www.magazine.noaa.gov/stories/pdfs/loeb.nature.paper.1997.pdf |bibcode=1997Natur.387..897L |s2cid=205032748 |access-date=2011-05-10 |archive-url=https://web.archive.org/web/20110524093822/http://www.magazine.noaa.gov/stories/pdfs/loeb.nature.paper.1997.pdf |archive-date=2011-05-24 |url-status=dead }}</ref> The scale for the ice is inverted to demonstrate the correlation; the horizontal line is the freezing point—the oblique line the average of the temperature.]]
A possible decline in Antarctic krill biomass may have been caused by the reduction of the [[pack ice]] zone due to [[global warming]].<ref name="Gr05">{{cite journal |author=Liza Gross |year=2005 |title=As the Antarctic ice pack recedes, a fragile ecosystem hangs in the balance |journal=[[PLOS Biology]] |volume=3 |issue=4 |page=e127 |doi=10.1371/journal.pbio.0030127 |pmid=15819605 |pmc=1074811 |doi-access=free }}</ref> Antarctic krill, especially in the early stages of development, seem to need the pack ice structures in order to have a fair chance of survival. The pack ice provides natural cave-like features which the krill uses to evade their predators. In the years of low pack ice conditions the krill tend to give way to [[salp]]s,<ref name="A+04">{{cite journal |author1=Angus Atkinson |author2=Volker Siegel |author3=Evgeny Pakhomov |author4=Peter Rothery |year=2004 |title=Long-term decline in krill stock and increase in salps within the Southern Ocean |journal=[[Nature (journal)|Nature]] |volume=432 |issue=7013 |pages=100–103 |doi=10.1038/nature02996 |pmid=15525989 |bibcode=2004Natur.432..100A|s2cid=4397262 }}</ref> a barrel-shaped free-floating [[filter feeder]] that also grazes on plankton.