( ( These plankton ) ( ( ( ( ( bloom annually ) ( in ( ( the ( ( spring and ) summer ) ) ( as ( day ( length ( increases ( and ( sea ( ice retreats ) ) ) ) ) ) ) ) ) ) , ) ( before ( ( lowering ( in number ) ) ( during ( the winter ) ) ) ) ) . ) )
(ROOT (S (NP (DT These) (NN plankton)) (VP (VBP bloom) (ADVP (RB annually)) (PP (IN in) (NP (NP (DT the) (NN spring) (CC and) (NN summer)) (PP (IN as) (NP (NN day) (NN length) (NNS increases) (CC and) (NN sea) (NN ice) (NNS retreats))))) (, ,) (PP (IN before) (S (VP (VBG lowering) (PP (IN in) (NP (NN number))) (PP (IN during) (NP (DT the) (NN winter))))))) (. .)))
These plankton bloom annually in the spring and summer as day length increases and sea ice retreats, before lowering in number during the winter.
(ROOT (S (NP (NP (DT A) (-LRB- -LRB-) (NN n) (-RRB- -RRB-) (NN increase)) (PP (IN in) (NP (NN length)))) (VP (VBZ happens) (PP (TO to) (NP (NN metal) (NN railroad) (NNS tracks))) (PP (IN during) (NP (NP (DT the) (NN heat)) (PP (IN of) (NP (DT a) (NN summer) (NN day)))))) (. .)))