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    Introduo Cincia do Sistema Terrestre

    Segunda Lista de Exerccios

    Questo 1

    Oscilaes milenares e mudanas abruptas no paleo-ambiente do

    Sistema Terrestre. A figura abaixo do livro texto indica registrospaleoclimticos na escala milenar para dois stios de pesquisa, indicandooscilaes na escala milenar e mudanas abruptas. Estude a figura, consultebibliografia especializada de modo a entender to completamente quantopossvel os dados apresentados. Suas respostas devem ser feitas num textoentre 1,5 e 3 pginas, com referncias e um glossrio de todos os termostcnicos.

    Fig. 2.6. Milennial scale oscillations and abrupt changes

    Low latitude expression of millennia scale climate oscillations taken fromGISP2 oxygen isotopes, Santa Barbara basin (Site 893) bioturbation index andhigh-frequency variations in the CaC03 record of 70KL (Behl and Kennett

    1996). Comparison of site 893 bioturbation index and benthic foraminiferal6180 records with 6180 ice time series from GISP2, showing the excellentcorrelation of site 893 anoxia (lamination) events to 16 of 17 of the warminterstadials of GISP2. Bioturbation index is presented as a 49 cm (ca. 300-400 years) running average to dampen high-frequency variation and to matchthe resolution of the GISP2 record. Chronologies for GISP2 and site 893 wereindependently derived. Radiocarbon age control points (+) and SPECMAP dataused for the site 893 age model are shown to the right. Numbers in 0 refer tostandard data of the SPECMAP stratigraphy. The base of each core interval inHole 893A is indicated by arrows to the left (Behl RJ, Kennett JP (1996) Brief

    interstadial events in the Santa Barbara Basin, NE Pacific, during the past 60kyr. Nature 379: 243-24

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    Questo 2

    Acidificao dos Oceanos. Com base no material includo a seguir e emoutros materiais sobre o assunto que voc pode consultar, o que vocentende pelo processo chamado de acidificao dos oceanos. Escreva umtexto entre 1,5 e 3 pginas.

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    Acidificao dos Oceanos

    (Feely et al., 2008)

    *

    Acidificao dos Oceanos

    pH = 7.8 aragonita no se forma

    ameaa 40% dos organismos

    marinhos de estrutura ssea

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    CO2absorption by the oceans

    Carbon dioxide is less soluble in warmer water

    Rising sea temperatures bring about less CO2absorption

    Positive feedback in abrupt transitions fromglacial to interglacial periods

    2.3.2 BiogeochemicalProcesses

    CO2absorption by the oceans

    Carbon dioxide is less soluble in warmer water

    Rising sea temperatures bring about less CO2absorption

    Positive feedback in abrupt transitions fromglacial to interglacial periods

    2.3.2 BiogeochemicalProcesses

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    Vilcinskas 2000

    Surface Ocean pH decreases with withincreasing atmospheric CO2:

    Solas Science and Implemantation Plan

    Time series of average surface [CO3-2] in

    the Southern Ocean for the PIUB-Bernreduced complexity model (Orr et al,Nature, 2005)

    2.3.2 BiogeochemicalProcesses

    From R. Buddemeier, based on Kleypas et al. 1999

    2.3.2 BiogeochemicalProcesses

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    From R. Buddemeier, based on Kleypas et al. 1999

    2.3.2 BiogeochemicalProcesses

    From R. Buddemeier, based on Kleypas et al. 1999

    2.3.2 BiogeochemicalProcesses

    Questo 3

    Estados mltiplos de equilbrio entre vegetao e clima.

    Possivelmente, o melhor exemplo da importncia da vegetao como fatorformador do clima pode ser derivado da mudana abrupta de vegetao noNorte da frica, de savana para deserto, no mdio Holoceno. Explique quetipo de interao entre a superfcie vegetada e a atmosfera possa ter ocorrido

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    que possa explicar o carter abrupto da mudana de vegetao (texto entre1,5 e 3 pginas).

    Source:Steffen at al., 2004. Global Change and the Earth System. A planet under preassure. IGBP Book Series. Springer VerlagChapter 2: Planetary Machinery: The dynamics of the earth system prior to significant human influence pg. 69.

    Fig. 2.60.The abrupt change fromsavanna to desert in North Africa duringthe mid-Holocene: a change in theregional flux of solar radiation at Earth'ssurface due to a small change in theEarth's orbit; b simulated change inrainfall ultimately triggered by thechange in incident solar radiation; cchange in fraction vegetation cover inresponse to changing rainfall; and dmodel predictions(solid line)andobservations(broken line)of theresulting increase in wind erosion and

    deposition of sand off the West Africancoast (Claussen et al. 1999; deMenocalet al. 2000)

    Springer

    -VelargBerlinHeidelberg2005