Watermelon snow 4337752 213584238 2008-05-19T23:31:16Z Bob the Wikipedian 1531408 {{Taxobox | name = ''Chlamydomonas nivalis'' |image=Green algal.jpg | regnum = [[Plant]]ae | phylum = [[Chlorophyta]] | classis = [[Chlorophyceae]] | ordo = [[Volvocales]] | familia = [[Chlamydomonadaceae]] | genus = ''[[Chlamydomonas]]'' | species = '''''C. nivalis''''' | binomial = ''Chlamydomonas nivalis'' | binomial_authority = (Bauer) [[Johan Nordal Fischer Wille|Wille]] }} '''Watermelon snow''', also called '''snow algae''', is [[snow]] that is reddish or pink in color, with the slight scent of a fresh [[watermelon]]. This type of snow is common during the summer in alpine and coastal polar regions worldwide, such as the [[Sierra Nevada (U.S.)|Sierra Nevada]] of [[California]]. Here, at altitudes of 10,000 to 12,000 feet (3,000–3,600&nbsp;m), the temperature is cold throughout the year, and so the snow has lingered from winter storms. Compressing the snow by stepping on it or making snowballs leaves it looking red. Walking on watermelon snow often results in getting bright red soles and pinkish pant cuffs. Watermelon snow is caused by the presence mainly of '''''Chlamydomonas nivalis''''', a species of [[green algae]] containing a secondary red [[carotenoid]] [[pigment]] ([[astaxanthin]]) in addition to [[chlorophyll]]. Unlike most species of fresh-water algae, it is [[Psychrophile|cryophilic]] (cold-loving) and thrives in freezing water.<ref>{{cite journal | title = Surface gas-exchange processes of snow algae | author = William E. Williams, Holly L. Gorton, and Thomas C. Vogelmann | journal = [[Proceedings of the National Academy of Sciences of the United States of America]] | date = [[January 21]], [[2003]] | volume = 100 | issue = 2 | pages = 562–566 | doi = 10.1073/pnas.0235560100 | url = http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=141035 }}</ref> Its specific epithet, ''nivalis'', is from [[Latin]] and refers to snow. ==History== [[Image:Watermelon snow pits.jpg|thumb|Unusual watermelon snow pits, superimposed with an orange-ish bootprint.]] The first accounts of watermelon snow are in the writings of [[Aristotle]]. Watermelon snow has puzzled mountain climbers, explorers, and [[natural history|naturalist]]s for thousands of years, some speculating that it was caused by mineral deposits or oxidation products that were leached from rocks. In May 1818, four ships sailed from England to search for the [[Northwest Passage]] and chart the Arctic coastline of North America. Severe weather made them finally turn the ships back, but the expedition made valuable contributions to science. Captain [[John Ross (Arctic explorer)|John Ross]] noticed crimson snow that streaked the white cliffs like streams of blood as they were rounding [[Cape York (Greenland)|Cape York]] on the northwest coast of [[Greenland]]. A landing party stopped and brought back samples to England. ''[[The Times]]'' wrote about this discovery on [[December 4]], [[1818]]:<ref>{{cite news | title = Red snow from the Arctic regions | work = [[The Times]] | pages = 2 | date = [[December 4]], [[1818]]}}</ref> {{cquote|Captain Sir John Ross has brought from [[Baffin Bay|Baffin's Bay]] a quantity of red snow, or rather snow-water, which has been submitted to <!-- chymical: This is not a typo!-->chymical analysis in this country, in order to the discovery of the nature of its colouring matter. Our credulity is put to an extreme test upon this occasion, but we cannot learn that there is any reason to doubt the fact as stated. Sir John Ross did not see any red snow fall; but he saw large tracts overspread with it. The colour of the fields of snow was not uniform; but, on the contrary, there were patches or streaks more or less red, and of various depths of tint. The liquor, or dissolved snow, is of so dark a red as to resemble red port wine. It is stated, that the liquor deposits a sediment; and that the question is not answered, whether that sediment is of an animal or vegetable nature. It is suggested that the colour is derived from the soil on which the snow falls: in this case, no red snow can have been seen on the ice.}} A follow-up article three days later erroneously concluded that the coloration was caused by meteoric iron deposits:<ref>{{cite news | title = The King's health | work=[[The Times]] | pages=2 | date=[[December 7]], [[1818]]}}</ref> {{cquote|Some doubt has been expressed as to the red snow observed by Sir John Ross and his associates in the newly discovered arctic region; but when it is known that the iron which was also found there, lying on the surface, in heaps, and in considerable quantities, was all meteoric, the doubt will cease, and the fact will admit of an easy solution. Sir John Ross brought home small specimens of this iron, which has been subjected by Mr. Professor Brande to the usual tests, and it is found to be precisely of the kind of the meteoric stones that occasionally fall in more southern latitudes. It is impregnated with nickel, which is never found in earth iron. That, therefore, which loads the atmosphere with the fluid which composes this meteoric iron, serves to colour the snow; iron being found to be the colourist of all metallic as well as vegetable matter.}} Watermelon snow was finally attributed to blooms of algae at the end of the nineteenth century. ==''Chlamydomonas nivalis''== [[Image:Watermelon snow streaks 3.jpg|thumb|left|Watermelon snow streaks.]] ''Chlamydomonas nivalis'' is a [[green alga]] that owes its red color to a bright red [[carotenoid]] [[pigment]], which protects the chloroplast from intense visible and also [[ultraviolet radiation]], as well as absorbing heat, which provides the alga with liquid water as the snow melts around it. [[Algal bloom]]s may extend to a depth of 25 cm (10 inches), with each cell measuring about 20 to 30 [[micrometers]] in diameter, about four times the diameter of a human [[red blood cell]]. It has been calculated that a teaspoon of melted snow contains a million or more cells. The algae sometimes accumulate in [[sun cup]]s, which are shallow depressions in the snow. The carotenoid pigment absorbs heat and as a result it deepens the sun cups, and accelerates the melting rate of [[glacier]]s and snowbanks. During the winter months, when snow covers them, the algae become dormant. In spring, nutrients, increased levels of light and meltwater, stimulate germination. Once they germinate, the resting cells release smaller green [[flagellate]] cells which travel towards the surface of the snow. Once the flagellated cells reach the surface, they may lose their [[flagella]]e and form [[aplanospore]]s, or thick-walled resting cells, or they may function as [[gamete]]s, fusing in pairs to form [[zygote]]s. Many species feed on ''C. nivalis'', including [[protozoa]]ns such as [[ciliate]]s, [[rotifers]], [[nematodes]], [[ice worm]]s and [[springtail]]s. ==References== *Armstrong, W.P. 1999. [http://waynesword.palomar.edu/plaug98.htm "Watermelon Snow: A Strange Phenomenon Caused by Algal Cells of The Chlorophyta"] Wayne's Word Noteworthy Plants: Aug 1998. (24 April 2006). <references/> ==See also== * [[Ice algae]]: algal communities encountered in annual and multi-year sea-ice. ==External links== <!-- * [http://www.chikyu.ac.jp/takeuchi/snowalgae.html Snow algae] LINK IS DEAD--> * [http://waynesword.palomar.edu/plaug98.htm Waynes word article] [[Category:Green algae]] [[Category:Snow]] [[de:Blutschnee]] [[it:Neve rossa]] [[pl:Śnieg arbuzowy]]