Aquatic life

Unit 1, Topic 2

2

Aquatic habitats

• Vary in characteristics• Streams• Rivers• Ponds• Lakes• Vernal pools

3

Aquatic flora• Ecological requirements

• Types:Sunlight, carbon dioxide, oxygen, nutrients, space

Microscopic photosynthetic protists

Macroscopic photosynthetic protists

Plants

4

Aquatic fauna

• Ecological requirements

• Types:–Microfauna (microscopic plankton)–Macrofauna (invertebrates and vertebrates)

Oxygen, space, plants, habitat, tolerance limits

5

Microfauna

6

Macroinvertebrates

• Worms• Insects• Molluscs

7

Vertebrates

• Amphibians• Reptiles• Fish• Birds• Mammals

8

Indicator Species: Biological Smoke Alarms

• Species that serve as early warnings of damage to a community or an ecosystem.– eg: Presence or absence of trout species in freshwater bodies because they are sensitive to temperature and oxygen levels.

9

Indicator species: Amphibians

• Frogs serve as indicator species because different parts of their life cycles can be easily disturbed.

Figure 7-3Figure 7-3

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Why are Amphibians Vanishing?

• Habitat loss and fragmentation.• Prolonged drought.• Pollution.• Increases in ultraviolet radiation.• Parasites.• Viral and Fungal diseases.• Overhunting.• Natural immigration or deliberate introduction of nonnative predators and competitors.

11

Invertebrate indicators

• Macroinvertebrates are good measures of longterm water quality

• Broadly classify as “sensitive”, “somewhat tolerant”, and “pollution tolerant”

• Scenarios:– We only find organisms that are “tolerant”. What can we definitively say about the longterm water quality?

– We find numerous individuals of a species that is “sensitive” to pollution and many individuals of various species that are “tolerant”. What can we definitively say about the longterm water quality?