LAUSR

Dissolved organic matter (DOM) input is a key factor for freshwater ecology, since it regulates many aspects of aquatic ecosystem metabolism. Aquatic and terrestrial animals that inhabit or frequent aquatic environments also influence the DOM inputs via their faeces, supplying nutrients such as carbon (C), nitrogen (N), and phosphorus (P). Here, we analyse the response of a bacterial community in the newly formed proglacial Lake Ventisquero Negro (Mount Tronador) to the addition of dissolved nutrients from faeces leachate of the native goose ( Chloephaga poliocephala Sclater, 1857; locally called “cauquén”) and the European hare ( Lepus europaeus Pallas, 1778). A laboratory incubation experiment was carried out with unenriched lake water and lake water enriched with leachate from hare or goose faeces. The results showed that faeces and leachates of geese were richer in nutrients than those of hares. Spectrofluorometric analysis of the DOM also showed differences between the two sources. Nutrient enrichment positively affected bacterial respiration and short-term carbon consumption. Thus, the faeces of these two animals may play an important ecological role by supplying allochthonous DOM and nutrients to this new ecosystem.