( ( ( ( ( Elevated ( nutrient concentrations ) ) , ) ( primarily ( caused ( by ( ( ( ( fertilizer application ) ( on ( fields ( upstream ( of ( most sites ) ) ) ) ) ) and ) ( ( municipal wastewater ) ( at ( a ( few sites ) ) ) ) ) ) ) ) ) , ) ( ( are ( causing eutrophication ) ) . ) )
(ROOT (S (NP (NP (JJ Elevated) (NN nutrient) (NNS concentrations)) (, ,) (VP (ADVP (RB primarily)) (VBN caused) (PP (IN by) (NP (NP (NP (NN fertilizer) (NN application)) (PP (IN on) (NP (NP (NNS fields)) (ADVP (RB upstream) (PP (IN of) (NP (JJS most) (NNS sites))))))) (CC and) (NP (NP (JJ municipal) (NN wastewater)) (PP (IN at) (NP (DT a) (JJ few) (NNS sites))))))) (, ,)) (VP (VBP are) (VP (VBG causing) (NP (NN eutrophication)))) (. .)))
Elevated nutrient concentrations, primarily caused by fertilizer application on fields upstream of most sites and municipal wastewater at a few sites, are causing eutrophication.
(ROOT (S (NP (NP (DT An) (NN excess)) (PP (IN of) (NP (NP (NNS fertilizers)) (CC and) (NP (JJ other) (NNS nutrients))))) (VP (VBZ causes) (ADJP (JJ eutrophication) (S (VP (TO to) (VP (VB occur)))))) (. .)))