First evidence of testate amoebae in Lago Fagnano (54° S), Tierra del Fuego (Argentina): Proxies to reconstruct environmental changes. (December 2015)

• Record Type: Journal Article
• Authors: Caffau, Mauro; Lenaz, Davide; Lodolo, Emanuele; Zecchin, Massimo; Comici, Cinzia; Tassone, Alejandro
• Is Part Of: Journal of South American earth sciences. Volume 64:Part 1(2015:Dec.)
• Page Start: 27
• Page End: 41
• Publication Date: 2015-12
• Subjects: Tierra del Fuego -- Lago Fagnano -- Testate amoebae -- Earthquake -- Environmental changes; Geology -- Latin America -- Periodicals; Earth sciences -- Latin America -- Periodicals; Geology -- Antarctica -- Periodicals; Earth sciences -- Antarctica -- Periodicals; Geology -- Caribbean Area -- Periodicals; Earth sciences -- Caribbean Area -- Periodicals; Géologie -- Amérique latine -- Périodiques; Sciences de la terre -- Amérique latine -- Périodiques; Géologie -- Antarctique -- Périodiques; Sciences de la terre -- Antarctique -- Périodiques; Géologie -- Caraïbes (Région) -- Périodiques; Sciences de la terre -- Caraïbes (Région) -- Périodiques; Earth sciences; Geology; Antarctica; Caribbean Area; Latin America; Periodicals; 550.5
• DOI: 10.1016/j.jsames.2015.09.007
• Languages: English
• ISSNs: 0895-9811

Abstract

Abstract: We report here the first findings of testate amoebae at high southern latitudes (54° S) from four gravity cores recovered in the Lago Fagnano (Tierra del Fuego, Argentina), where twelve taxa have been recognized. Among them, C entropyxis constricta "constricta", Centropyxis elongata, Difflugia globulus, Difflugia oblonga "oblonga", and Difflugia protaeiformis "amphoralis" are always present, while other taxa are randomly distributed. According to the sand/silt ratio in the different cores, the Total Organic Carbon content and the Carbon/Nitrogen ratio, as well as the presence/disappearance and abundance of testate amoebae from cluster analysis, we infer a correlation between major textural/granulometrical changes found in the cores and environmental changes. A seismic event occurred on 1949, which substantially modified the morphology of the eastern Lago Fagnano shoreline and the supply pattern from two main eastern tributaries of the lake, is recorded in the studied cores. This event has in part modified the distribution of testate amoebae taxa within the studied cores. Present results show that testate amoebae represent important indicators to detect changes occurring in the environment in which they live. Graphical abstract: Highlights: The first findings of testate amoebae at high southern latitudes (Tierra del Fuego, 54° S) is reported. Twelve taxa have been recognized Four gravity cores recovered in the Lago Fagnano (Tierra del Fuego, Argentina), have been analyzed. A correlation between major textural/granulometrical changes occurred during a seismic event (1949, Moment magnitude 7.5 earthquake), and testate amoebae distribution was found. Testate amoebae represent important indicators to detect changes occurring in the environment in which they live.