This document provides an overview of freshwater ecology, including the types and classification of freshwater ecosystems. It discusses the key limiting factors for freshwater habitats, such as light penetration, temperature, oxygen levels, and nutrient concentrations. Freshwater ecosystems are classified as lentic (still water) or lotic (flowing water). Lentic systems include lakes and ponds, while lotic systems include rivers and streams. Each system has different zones defined by factors like depth, flow, and light levels, which influence the types of organisms that can survive there.

1. FRESHWATER
ECOLOGY

2.  Freshwater ecology
 Types and limiting factors
 Classification
 Lentic communities
 Lotic and springs

3. - The study of freshwaterecosystem
- Freshwaterecosystems are a
subset of Earth’s aquatic
ecosystems. They include lakes,
ponds, streams, springs, and
wetlands.

4.  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.
 Classified on the basis of depth and flow of water

5.  A. Light Penetration
 1. Aphotic zone
 2. Photic zone
 B. Distance from the shore and depth of the body of
water
 1. Limnetic zone
 2. Profundal zone
 3. Benthic zone

6.  C. Amount of Organic Matter
 1. Oligotrophic – deep cold small surface area
relative to depth nutrient-poor phytoplankton are
sparse, not very productive don’t contain much life
waters often very clear sediments low in
decomposable organic matter
 2. Mesotrophic - moderate nutrient content
moderate amount of phytoplankton reasonably
productive

7.  EUTROPHIC – shallow warm large surface area
relative to depth nutrient-rich phytoplankton
more plentiful and productive waters often
murky high organic matter content in benthos
leads to high decomposition rates and
potentially low oxygen

9.  Temperature
 Current - Largely determine the
distribution if vital gases, salts and small
organisms
 Transparency - Turbidity
 Can be measured using an instrument
called a Secchi disk

10.  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

11.  Lentic ecosystem (Nonflowing water) Calm freshwater
habitat or standing water; it refers to standing or
relatively still water; from the Latin “lentus”, which
means sluggish.
 Lotic ecosystem (Flowing water) Washed or the running
water; refers to flowing water; from the Latin ‘lotus’, to
wash

12. Lakes
Ponds
Inland wetlands

13.  Lakes - is a body of relatively still fresh water of
considerable size, localized in a basin, that is
surrounded by land; vary in depth of 1m to more
than 200 m
 Formed by glacial erosion and deposition, shifts in
Earth’s crust, uplifting ,ountains or displacing rock
strata, craters of some extinct volcanoes,
landslides
 By nongeologic activity beaver dams streams to
make shallow but often extensive ponds; humans
create lakes by rivers and streams for power,
irrigation or water shortage and smaller ponds for
recreating fishing and wildlife

15.  Light penetration-influenced by silt and other
materials and natural attenuation
 Temperature-vary seasonally and with depth
 Oxygen-can be limiting especially in summer,
because only a small proportion of of the water
is in direct contact with air and respiration by
decomposers.
 These three strongly influence the distribution
and adaptations of life in lakes and ponds

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

17. Swamp - is
a wetland
that is
forested

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

19.  The waters are usually flowing and
exhibit a longitudinal gradation in
temperatures, concentration of
dissolved material, turbidity, and
atmospheric gases, from the source to
the mouth
 Include rivers and streams (outlets of
ponds and lakes); some emerge from
glaciers and flows in a direction
dictated by the lay of the land

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

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

22. RIVERCONTINUUM

23.  Stream- a thin body of water which has a
continuous flow of water, often referred to as a
creek or a brook.
 TWO SUBHABITATS
 1. Turbulent riffle – shallow water where velocity of
current is great enough; site of primary production
in the stream; periphyton or aufwuchs, diatoms,
cyanobacteria, and water moss dominate

24. 2. Pool – deeper water where velocity of current is reduced; site of
decomposition; major site of CO2 production during summer or
fall necessary for the maintenance of a constant supply of
bicarbonate in solution.

25.  Fast Stream
 Streamlined form
 Caddisflies, water
moss(Fontinalis), hevy-
branched filamentous
algae
 Slow Stream
 Larval forms of insects
have flattened bodies and
broad flat limbs that
enable them to cling to
stones
 Smallmouth bass with
compressed bodies
 Snails, burrowing
mayflies, catfish, water
striders

26.  Shredders – insect larvae that feed on coarse
particulate organic matter (CPOM); includes
caddisflies (Tricoptera) and stoneflies
(Plecoptera)
 Collectors – pick up the fine particulate organic
matter (FPOM) from what shredders and
microbes broken up,
 Include filtering collectors and
gathering collectors

27.  Grazers – feed on the algal coting of stones
and rubbles ; includes the beetle larvae, water
penny, and a number of mobile caddisfly larvae
 Gougers – burrow into water-logged limbs and
trunks of fallen tree

29.  Horizontal zone – obvious to the eye
 Littoral zone – shallow water zone; surrounds most
lakes and ponds, in which light reaches the bottom,
stimulating the growth of rooted plants
 Limnetic zone – open water; extends to the depth of
light penetration; inhabiting this zone are microscopic
phytoplanktons (autotrophs) and zooplanktons
(heterotrophs) and nektons (free-swimming organisms)
 Profundal zone – depth of light is compensated ; the
point at which respiration balances photosynthesis;
depends on a rain of organic material from the limnetic
zone for energy

30.  Vertical zone – influenced by depth of light
penetration
 Benthic zone/bottom region – common to both littoral
and profundal zones
 Primary place for decomposition

31.  Limnetic Zone-
 phytoplanktons like
desmids, diatoms,
filamentous algae
 Zooplanktons like tiny
crustaceans
 Nektons like fish like
summer fishes large
mouth bass, pike,
muskellurge; and winter
fish like lake trout

32.  Depends on the temperature and availability of
oxygen is limited because of depletion by
decomposers
 Only during spring and fall turnovers that life is
abundant in this zones
 Mostly decomposed substances are found here

33.  Organisms can tolerate cool temperatures and
low oxygen levels
 Anaerobic bacteria
 Periphyton/Aufwuchs which colonize the leaves
of submerged aquatic plants; on stones, woods
froming a crustlike growth of cyanobacteria
 Algae and diatoms are fast-growing and lightly
attached

36. VERTEBRATES INVERTEBRATES

37. Nature with our intelligent help,can cope with man’s
physiological needs and wastes, but she has no homeostatic
mechanisms to cope with bulldozers, concrete, and the kind
of agroindustrial air, water, and soil pollution that will be
hard to contain as long as the human population itself
remains out of control.
(Odum, 1971p. 361st
Ed.)

38. Thank You!!!