( Scientists ( ( have ( been ( ( ( divided ( in ( ( a ( fierce debate ) ) ( on ( ( the stability ) ( of ( ( the ( East ( Antarctic ( ice sheet ) ) ) ) ( since 1984 ) ) ) ) ) ) ) ) , ) ( when ( ( ( ( ( fossilized ( microscopic ( oceanic plants ) ) ) , ) ( called diatoms ) ) , ) ( were ( discovered ( in ( rocks ( deposited ( by ( glaciers ( in ( the ( Transantarctic Mountains ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Scientists)) (VP (VBP have) (VP (VBN been) (VP (VBN divided) (PP (IN in) (NP (NP (DT a) (JJ fierce) (NN debate)) (PP (IN on) (NP (NP (DT the) (NN stability)) (PP (IN of) (NP (NP (DT the) (NNP East) (NNP Antarctic) (NN ice) (NN sheet)) (PP (IN since) (NP (CD 1984))))))))) (, ,) (SBAR (WHADVP (WRB when)) (S (NP (NP (JJ fossilized) (JJ microscopic) (JJ oceanic) (NNS plants)) (, ,) (VP (VBN called) (NP (NNS diatoms))) (, ,)) (VP (VBD were) (VP (VBN discovered) (PP (IN in) (NP (NP (NNS rocks)) (VP (VBD deposited) (PP (IN by) (NP (NP (NNS glaciers)) (PP (IN in) (NP (DT the) (NNP Transantarctic) (NNPS Mountains))))))))))))))) (. .)))
Scientists have been divided in a fierce debate on the stability of the East Antarctic ice sheet since 1984, when fossilized microscopic oceanic plants, called diatoms, were discovered in rocks deposited by glaciers in the Transantarctic Mountains.
(ROOT (S (NP (NNS Scientists)) (VP (VBP know) (SBAR (IN that) (S (NP (DT some) (NNS mountains)) (VP (VBD were) (ADVP (RB once)) (PP (IN at) (NP (NP (DT the) (NN bottom)) (PP (IN of) (NP (DT an) (NN ocean))))) (SBAR (IN because) (S (NP (JJ marine) (NNS fossils)) (VP (VBP have) (VP (VBN been) (VP (VBN found) (PP (IN on) (NP (NP (DT the) (NNS peaks)) (PP (IN of) (NP (DT some) (NNS mountains)))))))))))))) (. .)))