( ( ( ( Algae ( secrete ( gas bubbles ) ) ) or ) ( have ( gas filled ) ) ) ( ( floats ( to ( ( ( keep them ) ( in ( sunlit ( surface waters ) ) ) ) ( to ( maximize photosynthesis ) ) ) ) ) . ) )
(ROOT (S (S (VP (VP (VB Algae) (NP (JJ secrete) (NN gas) (NNS bubbles))) (CC or) (VP (VB have) (NP (NP (NN gas)) (VP (VBN filled)))))) (VP (VBZ floats) (S (VP (TO to) (VP (VB keep) (NP (PRP them)) (PP (IN in) (NP (JJ sunlit) (NN surface) (NNS waters))) (S (VP (TO to) (VP (VB maximize) (NP (NN photosynthesis))))))))) (. .)))
Algae secrete gas bubbles or have gas filled floats to keep them in sunlit surface waters to maximize photosynthesis.
(ROOT (S (NP (NNP Gas) (NN bubble) (NNS holes)) (VP (VBZ helps) (NP (NP (JJ pumice) (NN float)) (PP (IN in) (NP (NN water))))) (. .)))