20
3 Biology of Fronts
on this layer’s production. Thus, the canopy is comparable to the euphotic layer
in the sea, while below lies an equivalent of benthos, where organisms live
entirely on secondary materials that fall from above (or roots and fungi). The
basis of such analogy is the three-dimensional character of the forest and the
ocean, and the equivalent significance of the vertical dimension in both types of
habitats (Fig. 3.5). In both cases, the maximum thickness in which the light can
be used and the chlorophyll is active is about 100 m high (Bates 1960; Margalef
1997). The main difference between primary producers of both types of ecosystems lies in the microscopic size of marine phytoplankton organisms, which
contrasts with the much larger size of terrestrial plants. The biomass of the trees
comprise a major fraction of transport and supporting tissues, which forms part
of a very effective system that brings nutrients from the ground to the lit canopy. Phytoplankton, on the other hand, appears as a community which is poorly
Fig. 3.5 Both in the forest and in the sea photosynthesis occurs in the well illuminated upper
part (the canopy and the euphotic zone, respectively) while remineralization takes place in the
lower and shadowy stratum. A main difference is that in terrestrial ecosystems the upward nutrient transport is internal and under plant’s control, while phytoplankton depends on the mechanical energy of the ocean for bring nutrients in the euphotic zone
3 Biology of Fronts
on this layer’s production. Thus, the canopy is comparable to the euphotic layer
in the sea, while below lies an equivalent of benthos, where organisms live
entirely on secondary materials that fall from above (or roots and fungi). The
basis of such analogy is the three-dimensional character of the forest and the
ocean, and the equivalent significance of the vertical dimension in both types of
habitats (Fig. 3.5). In both cases, the maximum thickness in which the light can
be used and the chlorophyll is active is about 100 m high (Bates 1960; Margalef
1997). The main difference between primary producers of both types of ecosystems lies in the microscopic size of marine phytoplankton organisms, which
contrasts with the much larger size of terrestrial plants. The biomass of the trees
comprise a major fraction of transport and supporting tissues, which forms part
of a very effective system that brings nutrients from the ground to the lit canopy. Phytoplankton, on the other hand, appears as a community which is poorly
Fig. 3.5 Both in the forest and in the sea photosynthesis occurs in the well illuminated upper
part (the canopy and the euphotic zone, respectively) while remineralization takes place in the
lower and shadowy stratum. A main difference is that in terrestrial ecosystems the upward nutrient transport is internal and under plant’s control, while phytoplankton depends on the mechanical energy of the ocean for bring nutrients in the euphotic zone