With no explanation, label each line with "O", "other-chemicalthing", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
Nutrient
pollution
is
a
primary
cause
of
eutrophication
of
surface
waters
,
in
which
excess
nutrients
,
usually
nitrates
or
phosphates
,
stimulate
algae
growth
.
Nutrient:O
pollution:O
is:O
a:O
primary:O
cause:O
of:O
eutrophication:O
of:O
surface:O
waters:O
,:O
in:O
which:O
excess:O
nutrients:O
,:O
usually:O
nitrates:other-chemicalthing
or:O
phosphates:other-chemicalthing
,:O
stimulate:O
algae:O
growth:O
.:O