Environmental Engineering Reference
In-Depth Information
Fig. 6.15
Telescopium
telescopium abundantly
found on the mudflats of
Sundarbans
Fig. 6.16
Littorina sp.
feeding on fresh mangrove
leaves
When gastropods consume and digest food,
carbon is introduced to the haemolymph and
passed along to the extrapallial fluid in the same
manner as atmospheric carbon dioxide. There, it
mixes with atmospheric carbon before becoming
incorporated in the shell carbonate (Wilbur
1972
). Carbon derived from urea takes a more
indirect pathway. Urea that is not expelled by the
gastropod breaks down into carbon dioxide and
ammonia via a urease reaction (Stott
2002
). The
resulting carbon dioxide is then reintroduced
directly to the extrapallial
1983
), 36
73 % (Romaniello et al.
2008
) and
w100 % (Stott
2002
).
Terrestrial gastropods ingest water from mul-
tiple sources, including dew, soil moisture,
standing water and precipitation, all of which
contain some amount of dissolved inorganic
carbon (DIC). Water is taken up through the foot
of the gastropod by contact rehydration (Bala-
krishnan and Yapp
2004
) and introduced to the
haemolymph before being passed on to the ex-
trapallial
-
uid.
The soft
fl
uid and ultimately
incorporated into the shell carbonate. Estimates
of the amount of carbon derived from plants,
either directly or indirectly through urea, vary
between 25 and 40 % (Goodfriend and Hood
fl
eshy meat and shells of gastropods
are storehouse of carbon as evidenced from the
concentrations of total carbon (% dry weight) in
the soft tissues and shells of gastropods. A com-
parative study conducted by the present authors
fl
