( ( ( ( Water chemistry ) : ) ( ( Lake Tanganyika ) ( is ( ( the lake ) ( in ( ( Rift Valley ) ( with ( the ( highest alkalinity ) ) ) ) ) ) ) ) ) . )
(ROOT (NP (NP (NNP Water) (NN chemistry)) (: :) (S (NP (NNP Lake) (NNP Tanganyika)) (VP (VBZ is) (NP (NP (DT the) (NN lake)) (PP (IN in) (NP (NP (NNP Rift) (NNP Valley)) (PP (IN with) (NP (DT the) (JJS highest) (NN alkalinity)))))))) (. .)))
Water chemistry : Lake Tanganyika is the lake in Rift Valley with the highest alkalinity.
(ROOT (S (NP (NNS Craters) (CC and) (NNS rifts)) (VP (VBP become) (NP (NNS lakes)) (SBAR (WHADVP (WRB when)) (S (NP (PRP they)) (VP (VBP fill) (PP (IN with) (NP (NN water))))))) (. .)))