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

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.

TYPES OF FRESHWATER HABITAT

I. Lentic habitat Calm freshwater habitat or standing water refers to standing or relatively still water, from the

Latin lentus, which means sluggish.II. Lotic Habitat

Washed or the running water refers to flowing water, from the Latin lotus, to

wash

Lentic Habitat

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

Lentic Habitat

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

Lentic Habitat

c. Swamp - is a wetland that is forested

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.

Lotic Habitat

a. Spring – kind of freshwater habitat where water flows out of the ground

Lotic Habitat

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

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.

LIMITING FACTORS

I. Temperature Water thermal properties combine to minimize

temperature changeII. Current

Current direction is a very important limiting factors

Largely determine the distribution if vital gases, salts and small organisms

LIMITING FACTORS

III. Transparency Turbidity, especially when caused by clay and slit

particles Can be measured using an instrument called a

Secchi disk

LIMITING FACTORS

IV. Concentration of respiratory gases Oxygen and carbon dioxide concentration are often

limiting in the fresh water environmentV. 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

MAJOR GROUPS OF FRESHWATER ORGANISMS

Classified into:1. Major niches (based on their position in the

energy level or food chain)a. Autotrophs (producers)b. Phagotrophs (Macroconsumers)c. Saphotrophs (microconsumers/decomposers)

MAJOR GROUPS OF FRESHWATER ORGANISMS

Classified Into:2. Life Form Of Habitat (Based On Their Mode Of

Life)a. Benthos – Resting Or Living In The Bottom Of

Sediments. Ex. Clams And Snailb. Periphyton – Organisms Living On The Stems And

Leaves Of Rooted Plants. Ex. algae, cyanobacteria

MAJOR GROUPS OF FRESHWATER ORGANISMS

Classified into:2. Life form of habitat (based on their mode of

life)c. Plankton – floating organisms whose movements

depend on the current.d. Nekton – swimming organisms able to navigate at

will. Ex. Fishese. Neuston – organisms resting or swimming on the

surface. Ex. protozoans, bacteria

MAJOR GROUPS OF FRESHWATER ORGANISMS

Classified into:3. Region or subhabitat

…. In lakea. Littoral zone – shallow water region with light

penetration to the bottom. b. Limnetic zone – open water zone to the depth of

effective light penetration which photosynthesis balances respiration.

c. Profundal zone – bottom and deep water area.

MAJOR GROUPS OF FRESHWATER ORGANISMS

Zones of a lake

MAJOR GROUPS OF FRESHWATER ORGANISMS

Classified into:3. Region or Subhabitat

….in streamsa. Rapid zone – shallow water where velocity of

current is great enoughb. Pool zone – deeper water where velocity of current

is reduced.

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