178
Examination of representative portions of the dolphin enterolith specimen
showed that both calcium phosphate carbonate (85 % of the outer shell of the stone)
and struvite (15 %) were the main components there. However the mineral phase’s
content within different layers, which were observed within the enterolith, was not
homogenous. For example “the largest layer of mineral that completely surrounded
the nidus was composed of 95 % calcium phosphate carbonate and 5 % struvite.
Additionally, a band within the internal portion of the enterolith consisted of 45 %
calcium phosphate carbonate and 55 % brushite,” (Burdett and Osborne 2010 ).
Interestingly, the chemical composition of this enterolith was similar with that of
vaginal calculi isolated from other delphinid species (Sawyer and Walker ( 1977 );
Woodhouse and Rennie 1991 ).
Faecoliths Marine leatherback turtles not only swallow wood, feathers, sand and
seaweed, but are also known to swallow plastic bags and man-made garbage such
as the twine and polystyrene (e.g. Brongersma 1969 ; Den Hanog and Van Nierop
1984 ). In some cases, these materials play a role of the nucleation side for biominerals formation. The large male leatherback beached at Harlech in North
Wales, UK (Eckert and Luginbuhl 1988 ) had a hard, clay-like ball at the junction
between the small and large intestines, while the rectum of a turtle beached at
Midway Atoll in the north-western Hawaiian Islands contained a hard, smooth,
ovoid ball (Davenport et al. 1993 ). The occurrence of hard masses in the intestine
of chelonians is not uncommon either, but these are usually formed from masses
of chitinous pans of insects or accumulated indigestible cellulose fi bres. Such
masses can cause constipation, though intestinal parasitic nematodes may help to
break the masses down. The faecolith from chelonian turtle reported by Davenport
et al. ( 1993 ) consisted, however, of biomineralized faecal material. The mineral
was found to be struvite.
Interestingly, much material of anthropogenic origin (plastics in sheet and linear
form, plus other packaging materials and monofi lament nylon) was incorporated
into the faecolith structure. It is hypothesized that the formation of struvite stems
from the interaction of the leatherback’s osmotic physiology with the metabolism of
faecal bacteria. The hind fl uid is likely to contain relatively high concentrations of
magnesium, calcium and sulphate ions, but little sodium or chloride. However, the
ammonium and phosphate ions of struvite are presumably derived from the faecal
bacteria (Davenport et al. 1993 ). While the formation of the faecolith may be pathological, it could alternatively be an adaptive response to package garbage (whether
natural or man-made).
3.7.1 Conclusion
The pathological biomineralization is related to poorly studied but very intriguing
phenomenon. Of course, we can accept that this kind of biomineralization is an
example of “uncontrolled pathological crystallization resulting in painful or even
3 Biocomposites and Mineralized Tissues
Examination of representative portions of the dolphin enterolith specimen
showed that both calcium phosphate carbonate (85 % of the outer shell of the stone)
and struvite (15 %) were the main components there. However the mineral phase’s
content within different layers, which were observed within the enterolith, was not
homogenous. For example “the largest layer of mineral that completely surrounded
the nidus was composed of 95 % calcium phosphate carbonate and 5 % struvite.
Additionally, a band within the internal portion of the enterolith consisted of 45 %
calcium phosphate carbonate and 55 % brushite,” (Burdett and Osborne 2010 ).
Interestingly, the chemical composition of this enterolith was similar with that of
vaginal calculi isolated from other delphinid species (Sawyer and Walker ( 1977 );
Woodhouse and Rennie 1991 ).
Faecoliths Marine leatherback turtles not only swallow wood, feathers, sand and
seaweed, but are also known to swallow plastic bags and man-made garbage such
as the twine and polystyrene (e.g. Brongersma 1969 ; Den Hanog and Van Nierop
1984 ). In some cases, these materials play a role of the nucleation side for biominerals formation. The large male leatherback beached at Harlech in North
Wales, UK (Eckert and Luginbuhl 1988 ) had a hard, clay-like ball at the junction
between the small and large intestines, while the rectum of a turtle beached at
Midway Atoll in the north-western Hawaiian Islands contained a hard, smooth,
ovoid ball (Davenport et al. 1993 ). The occurrence of hard masses in the intestine
of chelonians is not uncommon either, but these are usually formed from masses
of chitinous pans of insects or accumulated indigestible cellulose fi bres. Such
masses can cause constipation, though intestinal parasitic nematodes may help to
break the masses down. The faecolith from chelonian turtle reported by Davenport
et al. ( 1993 ) consisted, however, of biomineralized faecal material. The mineral
was found to be struvite.
Interestingly, much material of anthropogenic origin (plastics in sheet and linear
form, plus other packaging materials and monofi lament nylon) was incorporated
into the faecolith structure. It is hypothesized that the formation of struvite stems
from the interaction of the leatherback’s osmotic physiology with the metabolism of
faecal bacteria. The hind fl uid is likely to contain relatively high concentrations of
magnesium, calcium and sulphate ions, but little sodium or chloride. However, the
ammonium and phosphate ions of struvite are presumably derived from the faecal
bacteria (Davenport et al. 1993 ). While the formation of the faecolith may be pathological, it could alternatively be an adaptive response to package garbage (whether
natural or man-made).
3.7.1 Conclusion
The pathological biomineralization is related to poorly studied but very intriguing
phenomenon. Of course, we can accept that this kind of biomineralization is an
example of “uncontrolled pathological crystallization resulting in painful or even
3 Biocomposites and Mineralized Tissues