There
are a number of ways that human activity increase nitrogen running
off into rivers. Dead zones can develop with too much nitrogen build
up and that is bad for fishing.
In
the long run, not just over-fishing and direct habitat destruction
from road building and mining activity bring ruin to fisheries,
nitrogen as well as acidification each challenge life in rivers and
possibly oceans to exist.
It
is easy to imagine a great river like the Yukon accumulating over
time myriad new sources of nitrogen input from farming and
fertilizer, auto exhaust etc. Downstream the Bering Sea could be the
immediate casualty as well as the river itself. It would be great if
public land use designers could anticipate these temporal
‘externalities’ to various business and recreational activity
that bring about dead zones in the long run.
