Freshwater Ecology

1. FRESHWATER ECOLOGY is the study of a freshwater ecosystem or also termed as Limnology is a specialized subcategory of the overall study of organisms and the environment. Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes and ponds, rivers, streams and springs, and wetlands

2. FRESHWATER ECOLOGY Freshwater habitats can be classified by different factors, including temperature, light penetration, transparency, etc. Freshwater ecosystems can be divided into lentic ecosystems and lotic ecosystems.

3. TYPES OF FRESHWATER HABITAT Lentic habitat Calm freshwater habitat or standing water refers to standing or relatively still water, from the Latin lentus , which means sluggish. Lotic Habitat Washed or the running water refers to flowing water, from the Latin lotus , to wash

4. Lentic Habitat Lakes - is a body of relatively still fresh water of considerable size, localized in a basin, that is surrounded by land.

5. Lentic Habitat b . Ponds- body of standing water, either natural or man-made, that is usually smaller than a lake.

6. Lentic Habitat c . Swamp - is a wetland that is forested

7. Lentic Habitat d . Bog - is a wetland that accumulates peat, a deposit of dead plant material—often mosses, and in a majority of cases, Sphagnum moss.

8. Lotic H abitat a. Spring – kind of freshwater habitat where water flows out of the ground

9. Lotic Habitat b. River - is a body of water with current moving in one general direction .

10. Lotic Habitat c. Stream - a thin body of water which has a continuous flow of water, often referred to as a creek or a brook.

11. LIMITING FACTORS I. Temperature Water thermal properties combine to minimize temperature change II. Current Current direction is a very important limiting factors Largely determine the distribution if vital gases, salts and small organisms

12. LIMITING FACTORS III. Transparency Turbidity, especially when caused by clay and slit particles Can be measured using an instrument called a Secchi disk

13. LIMITING FACTORS Concentration of respiratory gases Oxygen and carbon dioxide concentration are often limiting in the fresh water environment Concentration of biogenic salts Nitrates and phosphates seem to be limiting in a freshwater ecosystem Calcium and other salts are likely to be limiting in soft water lakes and streams

14. MAJOR GROUPS OF FRESHWATER ORGANISMS Classified into: Major niches (based on their position in the energy level or food chain) Autotrophs (producers) Phagotrophs (Macroconsumers) Saphotrophs (microconsumers/decomposers)

15. MAJOR GROUPS OF FRESHWATER ORGANISMS Classified Into: Life Form Of Habitat (Based On Their Mode Of Life) Benthos – Resting Or Living In The Bottom Of Sediments. Ex. Clams And Snail Periphyton – Organisms Living On The Stems And Leaves Of Rooted Plants. Ex . algae, cyanobacteria

16. MAJOR GROUPS OF FRESHWATER ORGANISMS Classified into: Life form of habitat (based on their mode of life) Plankton – floating organisms whose movements depend on the current. Nekton – swimming organisms able to navigate at will. Ex. Fishes Neuston – organisms resting or swimming on the surface. Ex. protozoans, bacteria

17. MAJOR GROUPS OF FRESHWATER ORGANISMS Classified into: Region or subhabitat …. In lake Littoral zone – shallow water region with light penetration to the bottom. Limnetic zone – open water zone to the depth of effective light penetration which photosynthesis balances respiration. Profundal zone – bottom and deep water area.

18. MAJOR GROUPS OF FRESHWATER ORGANISMS Zones of a lake

19. MAJOR GROUPS OF FRESHWATER ORGANISMS Classified into: Region or Subhabitat ….in streams Rapid zone – shallow water where velocity of current is great enough Pool zone – deeper water where velocity of current is reduced.

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