Biota of Aquatic Environemnts

1
(No Transcript)
2
Aquatic Macrophytes

• Free-floating (very significant in tropics,
  particularly in water bodies with fluctuating
  water levels)
• - Lemna (duckweed), Salvinia (water fern),
  Eichhornia (water hyacinth)
• Rooted (confined to the shallow water)
• - Emergent Typha (cattail), Phragmites (giant
  reed)
• - Submergent Hydrilla, Utricularia
  (bladderwort)
• - Floating-leaved Nymphaea (water lily),
  Victoria amazonica (giant water lily)

3
Lemna (duckweed)
Floating Aquatic Macrophytes
Eichhornia (water hyacinth)
4
Water hyacinth Eichhornia crassipes
Giant water lily Victoria amazonica
5
Floating-leaved (Nymphaea odorata)
Submerged (Hydrilla verticillata)
Emergent (Panicum hemitomon)
6
Changes in vegetation with water depth Zonations
commonly applied to temperate zone lakes and
rivers
7
Riparian vegetation (bank of a river or other
body of water)
8
Phragmites australis (Giant reed) Native to the
United States. Genetic analysis has shown,
however, that more aggressive European genotypes
have replaced the native genotype in much of the
former American range and have invaded new areas.
9
Stream order nomenclature
10
(No Transcript)
11
(No Transcript)
12
During annual floods, over 200 species of fish
consume fruits that fall into the water of South
American floodplain forests.
Colossoma macropomum
13
(No Transcript)
14
Seasonally inundated floodplain forest along
Amazon River. Note white and black water
stretches (True-color Terra MODIS image
September 8, 2002).
15
High-resolution image of Amazonia. Farms cleared
from the jungle spread out on either side of a
narrow dirt road. Above and to the right of the
river is almost unbroken forest. The river, a
tributary of the Amazon, is colored brown by the
large amount of sediment it carries, possibly the
result of deforestation upstream.
Source IKONOS satellite Space Imaging Corporation
16
(No Transcript)
17
Azolla caroliniana
18
Cultural eutrophication (due to sewage inflow,
nutrient runoff, soil erosion, etc) causes
conditions with either excessive macrophytes or
excessive algae. What factors determine whether
a lake will be dominated by plants or by algae?

• The pre-impact condition of the lake
• The extent of the littoral zone
• The nutrient loading rates

19
(No Transcript)