of the organic remains included in them. Murray determined bizarre algae
(Discophaera thomsoni [Order Coccosphaerales]), diatoms, radiolarians, and a
few fish bones. It is remarkable that the author already described that those organic
seed structures represent the origin of the deposits. Besides a profound analysis of
the nodules, Murray gave also the first descriptions of the phosphatic concretion/
crusts, collected during the Challenger Expedition (Murray 1891) and later during
the Valdivia Expedition (Murray and Philippi 1908). Already, first reflections on
the mode of synthesis of crusts and nodules were outlined including also organic
matter and “granular and fragmentary objects” that facilitate the oxidation of Fe(II)
to Fe(III) and Mn(II) to Mn(IV), involving also the hydration intermediates. The
present-day collection of nodules and crusts for geophysical prospecting, e.g., by
the German research vessel “Sonne” or the Chinese “Haiyang 4,” follows the same
principles and uses almost the same methods (Fig. 4.2d and e).
4.3 Principles of Biomineralization in Marine Ore
Lowenstam and Weiner (Lowenstam 1981; Lowenstam and Weiner 1989; Weiner
and Dove 2003) introduced a classification of biomineralization processes
(Fig. 4.3). They distinguished two categories of biomineralization; first, the
BIOLOGICALLY INDUCED MINERALIZATION (Fig. 4.3d). Biominerals represent genuine
composite materials, formed from the inorganic “polymer”/mineral and the organic
component (protein, polysaccharide, glycoprotein). The processes of biomineralization occur extracellularly and describe reactions proceeding on the interface
between organic membranes and the inorganic environment. Such reactions are
frequently observed in the aquatic milieu (within an organism or outside of it)
during nucleation of epicellular mineralization processes and are characterized by a
certain degree of heterogeneity (Bazylinski and Frankel 2003). The inhomogeneity
in the element composition of biominerals is due to the concentrations of the
inorganic chemical components in the environment, e.g., in the water, which
counteract the selection processes, guided by the organic molecules. Biomineralization processes can be subdivided first into a SEED PHASE, during which the organic
matrix functions as a nucleation platform for the deposition of the mineral. In order
to distinguish the organic component that initiates a biomineralization process,
from an inorganic nucleus that initiates crystallization of a mineral, the term bioseed is appropriate. While inorganic seed particles allow controlled nucleations and
crystal growth in a supersaturated environment of the inorganic precursors, bioseeds facilitate the initiation of biomineral formation also in non-saturated
concentrations of the inorganic precursors. An example is the marine snow, amorphous aggregations of organic particles that display not only adverse effects on
the marine biota but have also mineralization activity. Marine snow is a threedimensional organic/mineral meshwork (Amy et al. 1987; Herndl 1988; M€ uller
et al. 1998; Leppard 1999) that is formed in the photic zone down to 100 m (Cottrell
4 Biogenic origin of nodules and crusts
81
(Discophaera thomsoni [Order Coccosphaerales]), diatoms, radiolarians, and a
few fish bones. It is remarkable that the author already described that those organic
seed structures represent the origin of the deposits. Besides a profound analysis of
the nodules, Murray gave also the first descriptions of the phosphatic concretion/
crusts, collected during the Challenger Expedition (Murray 1891) and later during
the Valdivia Expedition (Murray and Philippi 1908). Already, first reflections on
the mode of synthesis of crusts and nodules were outlined including also organic
matter and “granular and fragmentary objects” that facilitate the oxidation of Fe(II)
to Fe(III) and Mn(II) to Mn(IV), involving also the hydration intermediates. The
present-day collection of nodules and crusts for geophysical prospecting, e.g., by
the German research vessel “Sonne” or the Chinese “Haiyang 4,” follows the same
principles and uses almost the same methods (Fig. 4.2d and e).
4.3 Principles of Biomineralization in Marine Ore
Lowenstam and Weiner (Lowenstam 1981; Lowenstam and Weiner 1989; Weiner
and Dove 2003) introduced a classification of biomineralization processes
(Fig. 4.3). They distinguished two categories of biomineralization; first, the
BIOLOGICALLY INDUCED MINERALIZATION (Fig. 4.3d). Biominerals represent genuine
composite materials, formed from the inorganic “polymer”/mineral and the organic
component (protein, polysaccharide, glycoprotein). The processes of biomineralization occur extracellularly and describe reactions proceeding on the interface
between organic membranes and the inorganic environment. Such reactions are
frequently observed in the aquatic milieu (within an organism or outside of it)
during nucleation of epicellular mineralization processes and are characterized by a
certain degree of heterogeneity (Bazylinski and Frankel 2003). The inhomogeneity
in the element composition of biominerals is due to the concentrations of the
inorganic chemical components in the environment, e.g., in the water, which
counteract the selection processes, guided by the organic molecules. Biomineralization processes can be subdivided first into a SEED PHASE, during which the organic
matrix functions as a nucleation platform for the deposition of the mineral. In order
to distinguish the organic component that initiates a biomineralization process,
from an inorganic nucleus that initiates crystallization of a mineral, the term bioseed is appropriate. While inorganic seed particles allow controlled nucleations and
crystal growth in a supersaturated environment of the inorganic precursors, bioseeds facilitate the initiation of biomineral formation also in non-saturated
concentrations of the inorganic precursors. An example is the marine snow, amorphous aggregations of organic particles that display not only adverse effects on
the marine biota but have also mineralization activity. Marine snow is a threedimensional organic/mineral meshwork (Amy et al. 1987; Herndl 1988; M€ uller
et al. 1998; Leppard 1999) that is formed in the photic zone down to 100 m (Cottrell
4 Biogenic origin of nodules and crusts
81