Lobby > Exhibits > Hot Spring Ecology > Hydrothermal Influx in Fresh Water > Aquatic Macroinvertebrates
More types and greater numbers of insect larvae are present in the parts of the
Firehole River warmed by hydrothermal influx. The bicarbonates increase plant growth,
which means there are more surfaces for bottom-dwelling creatures to attach themselves,
as well as more available food.
The macroinvertebrates in the thermally influenced waters vary more in shape and
size than their counterparts in cooler water, and some species demonstrate changes
in respiration, growth rates, and feeding behavior.
Most stream insects have an annual turnover-once a species hatches, the entire
population disappears from the water and doesn't reappear until the following year.
However, in thermally influenced areas, some of these stream insects are reproducing
two times a year!
1 > 2 > 3 > 4 > 5 | Next Section: Microbes