Organisms that are large (macro) enough to be seen with the naked eye and lack a backbone (insects in their larval or nymph form, crayfish, clams, snails, and worms).
Most live most of their life cycle attached to submerged rocks, logs, and vegetation.
Macroinvertebrates - indicators of Topolniţa River water quality
Collecting
macroinvertebrates
What are the macroinvertebrates ?
References
1. Luiza Florea, Hidrobiologie, Caiet de laborator, Universitatea "Dunărea de Jos" Galati, 2006
2. http://water.epa.gov/
The locations for collecting samples
Macroinvertebrates as bioindicators
1. Spend up to one year in
the stream.
2. Have little mobility
3. They are affected by the
physical, chemical, and biological
conditions of the stream.
4. They are relatively easy
to sample and identify.
- direct tributary of the Danube
- 44 km length
- flows into the Danube at east of Drobeta Turnu - Severin
Group 1 - pollution sensitive
(require higher DO, neutral pH, cold water)
Ex. mayflies, stoneflies, caddisflies
- 11 km length
- the second largest in the country
the 17th largest in the world
Identified macroinvertebrates
Mayfly Nymph
Ecdyonurus sp.
Ephemeroptera
Common pond skater Common water strider
Categories
of
Stream
Macroinvertebrates
Gerris lacustris
Hemiptera
Ecdyonurus is a genus of mayfly, aquatic insects whose immature stage (called "nymph") usually lasts one year in fresh water. The adults are short-lived, from a few minutes to a few days.
Is declared a natural monument
Group 2 – somewhat pollution
tolerant
They have six legs; the first pair is short and stubby while the other two pairs are thin and elongated which are used for moving over the water surface which we call "walking on water".
Stonefly nymph
Perla cephalotes
Plecoptera
Water strider
Argyroneta aquatica
Gerridae
All species of Plecoptera are intolerant of water pollution, and their presence in a stream is an indicator of good water quality.
Ex. scuds, dragonflies, damselflies
It is the only spider known to spend its whole life under water. It breathes air, which it traps in a bubble held by hairs on its abdomen and legs. This gives it a silvery appearance.
Damselfly Nymph
Calopteryx
Calopteryx is a genus of large damselflies belonging to the family Calopterygidae.
Fresh water amphipod crustacean
Conclusions
Gammarus pulex (sp.)
Amphipoda
Austropotamobius torrentium
Astacidae
Adult males may reach a total length of 21 mm,
while females only grow to 14 mm
Drobeta Turnu-Severin
Schitul Topolniţei
Is an European species of freshwater crayfish in the family Astacidae
The preferred habitat is cold, fast-flowing streams. It digs burrows in the
banks and hides under submerged roots or rocks, emerging at night to feed.
Healthy stream
We identified several problems related to water pollution:
- the water is turbid, full of sand (due to a sandy bottom)
- lack of vegetation on the river banks.
- sewage smell (we are near a former city garbage dump).
- the presence of litter, plastic bottles, plastic bags, tires and other garbages on the stream bank or in the river
- the presence of the ballast station, causing changes in landforms, the accumulation of waste, disturbance of ecosystems.
Macroinvertebrates identified :
1. Dominant organisms
Mayfly Nymph
Stonefly Nymph
2. Rare
Fresh water amphipod
Stone crayfish
Common pond skater
Group 3 - Pollution tolerant
(can tolerate low oxygen,
lower/higher pH, warmer water)
Macroinvertebrates identified :
Rare organisms
Mayfly Nymph
Damselfly Nymph
Water spider
Common pond skater
Stone crayfish
Ex. Water Striders, aquatic worms, midge larva
Unhealthy stream
From Schitul Topolnitei to Drobeta Turnu-Severin, the river Topolnita passes through 4 villages: Schitul de Jos, Balotesti, Izvorul Barzii, Rascolesti and in almost 20 km the quality of water is changed from an "excellent water" to a "polluted water", due to the presence of human and to the negligence, indifference towards the environment.