fresh and marine water

1. Maintaining a body in a “steady
state”
Homeostasis
©
Cincinnati
Zoo
By
Dr. Priti D.Diwan
Assistant Professor
Department of Zoology
J.D.Patil Sangludkar Mahavidyalay Daryapur.

2. Environments where freshwater is
scarce:
• Desert
• Invertebrates
• Reptiles
• Terrestrial Mammals
• Ocean
• Invertebrates
• Fish
• Marine Mammals, Turtles, & Birds
• Hypersaline Lakes
• Invertebrates

3. Adaptations for osmoregulation
(water balance)
• ↓ Water Loss
– Conservation
– Utilization (↑Efficiency)
– ↑ Storage capacity
– ↕ Solute/waste excretion

4. LE 44-5
Water
balance in a
kangaroo rat
(2 mL/day)
Water
balance in
a human
(2,500 mL/day)
Water
gain
Water
loss
Derived from
metabolism (1.8 mL)
Ingested
in food (0.2 mL)
Derived from
metabolism (250 mL)
Ingested
in food
(750 mL)
Ingested
in liquid
(1,500 mL)
Evaporation (900 mL)
Feces (100 mL)
Urine
(1,500 mL)
Evaporation (1.46 mL)
Feces (0.09 mL)
Urine
(0.45 mL)

5. Adaptations for osmoregulation
(water balance)
• ↓ Water Loss
– Conservation
– Utilization (↑Efficiency)
– ↑ Storage capacity
– ↕ Solute/waste excretion

6. LE 44-8
Nitrogenous bases
Nucleic acids
Amino acids
Proteins
—NH2
Amino groups
Most aquatic
animals, including
most bony fishes
Mammals, most
amphibians, sharks,
some bony fishes
Many reptiles
(including birds),
insects, land
snails
Ammonia Urea Uric acid

7. Marine Invertebrates
• Most inverts are osmo –
isotonic with environment
(e.g. sponges)
• Some have specialized
protonephridia composed
of ciliated flame cells to
transport solutes and
waste products for
elimination
Polyclad Flatworm

8. Osmoregulation in marine fish
Marine fish face two problems: they tend to
lose water and gain ions.

9. Osmoregulation in freshwater fish
Freshwater fish face two problems: they tend
to lose ions and gain water.

11. Filtration

12. Metanephridia: most annelids

13. Green Sea Turtle
(Chelonia mydas)
• The primary osmo-regulatory
mechanism in sea turtles is the salt
gland
• The surface area: volume ratio is
different for age classes: a 50g
immature has greater surface area,
and larger relative salt glands (0.3% of
body size) than a 50 kg subadult (0.05
–0.1%)
– i.e., osmotic challenge varies by age
Kingdom Animalia Phylum Chordata Subphylum Vertebrata Class
Reptilia Order Testudines Family Cheloniidae

14. Leatherback Sea
Turtle
(Dermochelys coriacea)
• Salt glands secrete monovalent ions (Na+),
which is the main constituent of seawater,
while renal system processes bivalent ions
(Mg++)
• Sea turtles, marine reptiles & marine birds:
super-saline secretions from salt glands
– Lacrymal (turtles) – eye secretions
– Nasal (lizards)
– Post-orbital (birds)
– Sublingual or premaxillary (snakes)
– Lingual (crocodiles)
Kingdom Animalia Phylum Chordata Subphylum Vertebrata Class
Reptilia Order Testudines Family Dermocheliidae
Prange, H.D. 1985. Osmoregulation: water and salt balance in sea turtles Copeia 1985
(3): 771-776.
Hudson, D. M. and P. L. Lutz 1986. Salt Gland Function in the Leatherback Sea Turtle,
Dermochelys coriacea Copeia, 1986 (1):247-249

15. Salt glands in marine birds
Nostril
with salt
secretions
Nasal salt gland
• Salt glands of marine birds remove excess sodium chloride
from the blood
• Use transport epithelia, which are specialized cells that
regulate solute movement arranged in complex tubular
networks
Pink-footed Shearwater (P. Hodum)
Puffinus cretapus