7. EPILOGUE
there seems to be a large variation in basic growth processes, and consequently architectures, possible. For example the organisms shown in Fig. 1.4
are formed in a radiate accretive growth process . This type of growth pro -
cess was also used as a case study in Sect. 4.6 on accretive growth models. It
is possible to identify many other different types of basic growth processes
and architectures in marine sessile organisms (see for example for sponges
Wiedenmayer 1977). An example was also given in Fig. 2.19, of a skeleton with
a dense axial condensation, resulting in a very different overall architecture.
In seaweeds it is possible to distinguish a wide variety of different types of
growth processes. Simulation models in which more of these basic growth
patterns are included might enable us to further explore the morphospace of
possible morphologies.
UNDERWATER LIGHT MODELS. Until now only highly simplified models of
underwater light distributions have been applied in the growth models. In
reality factors such as reflection and scattering (for example due to suspended
material) for various wave lengths, the position of the sun during a day, etc.,
may have an important role. To investigate these questions, more elaborate
light models are required.
In many marine sessile organisms, for example in stony corals, a combination is used of photosynthesis and filter feeding. In general the literature
on these organisms gives no quantitative indication about the ratio between the two energy sources. This type of information is required for the
construction of models of organisms using this mixed energy source. An alternative approach could be to explore the photosynthesis/particle feeding
space systematically through simulation.
GROWTH INTURBULENT FLOW. In all the simulated growth processes, presented in Sects. 4.5 and 4.6, a laminar flow regime was assumed. Although
this assumption is valid to a certain extent for a part of the marine environment, in reality many of the marine sessile organisms inhabit an environment
exposed to higher flow velocities. Consequently in simulations it is required
to simulate turbulent flow in three dimensions. The method discussed in
Sect. 4.3 is basically suitable for simulating flows for higher Reynolds numbers, although quite a few computational problems can be expected here. For
example it might be necessary to scale up the dimensions of the simulation
box, increase the simulation time, and adapt the tracer step. Turbulence can
be expected to have a strong mechanical influence as well as a strong impact on the distribution of food particles. In simulations the Re and Pe (see
(2.3) and (2.4)) parameter space can be explored and it becomes possible
to construct morphodiagrams, similar to the photosynthesis/particle feeding parameter space discussed in the previous paragraph. Morphodiagrams
give an overview of all potential morphologies and are for example used in
evolutionary studies (see McGhee 1998).
THREE-DIMENSIONAL MORPHOLOGICAL ANALYSIS. In Chap.j we presented several methods for two-dimensional morphological analysis and
some preliminary results for three-dimensional morphological analysis of
marine sessile organisms. At least to our knowledge, there seems to be very
little work done on the morphological analysis of modular organisms; work
on the three-dimensional morphological analysis of these organisms is vir171
there seems to be a large variation in basic growth processes, and consequently architectures, possible. For example the organisms shown in Fig. 1.4
are formed in a radiate accretive growth process . This type of growth pro -
cess was also used as a case study in Sect. 4.6 on accretive growth models. It
is possible to identify many other different types of basic growth processes
and architectures in marine sessile organisms (see for example for sponges
Wiedenmayer 1977). An example was also given in Fig. 2.19, of a skeleton with
a dense axial condensation, resulting in a very different overall architecture.
In seaweeds it is possible to distinguish a wide variety of different types of
growth processes. Simulation models in which more of these basic growth
patterns are included might enable us to further explore the morphospace of
possible morphologies.
UNDERWATER LIGHT MODELS. Until now only highly simplified models of
underwater light distributions have been applied in the growth models. In
reality factors such as reflection and scattering (for example due to suspended
material) for various wave lengths, the position of the sun during a day, etc.,
may have an important role. To investigate these questions, more elaborate
light models are required.
In many marine sessile organisms, for example in stony corals, a combination is used of photosynthesis and filter feeding. In general the literature
on these organisms gives no quantitative indication about the ratio between the two energy sources. This type of information is required for the
construction of models of organisms using this mixed energy source. An alternative approach could be to explore the photosynthesis/particle feeding
space systematically through simulation.
GROWTH INTURBULENT FLOW. In all the simulated growth processes, presented in Sects. 4.5 and 4.6, a laminar flow regime was assumed. Although
this assumption is valid to a certain extent for a part of the marine environment, in reality many of the marine sessile organisms inhabit an environment
exposed to higher flow velocities. Consequently in simulations it is required
to simulate turbulent flow in three dimensions. The method discussed in
Sect. 4.3 is basically suitable for simulating flows for higher Reynolds numbers, although quite a few computational problems can be expected here. For
example it might be necessary to scale up the dimensions of the simulation
box, increase the simulation time, and adapt the tracer step. Turbulence can
be expected to have a strong mechanical influence as well as a strong impact on the distribution of food particles. In simulations the Re and Pe (see
(2.3) and (2.4)) parameter space can be explored and it becomes possible
to construct morphodiagrams, similar to the photosynthesis/particle feeding parameter space discussed in the previous paragraph. Morphodiagrams
give an overview of all potential morphologies and are for example used in
evolutionary studies (see McGhee 1998).
THREE-DIMENSIONAL MORPHOLOGICAL ANALYSIS. In Chap.j we presented several methods for two-dimensional morphological analysis and
some preliminary results for three-dimensional morphological analysis of
marine sessile organisms. At least to our knowledge, there seems to be very
little work done on the morphological analysis of modular organisms; work
on the three-dimensional morphological analysis of these organisms is vir171