156
Benthic Microftora, Periphyton and Plant Associations
The primary production of benthic plant associations was measured in
different individuals of their common species (Marsh 1970; Quasim and
Bhattathiri 1971; Wanders 1976b; West and Larcum 1983; Titlyanov et al.
1983b, 1985; Morrissey 1985) as well as in their associations inhabiting
different reef zones (Odum and Odum 1955; Marsh 1970, 1974; Wanders
1976b; Odum et al. 1959; Murphey and Kremer 1983; Littler 1979). The 14C
and oxygen release methods were employed (ct. Sect. 10.1). In crustose
coralline algae the gross photosynthesis varies within 1O-20I1gCcm-2h-l
(0.03-0.06I1g 02cm-2h-1), which is equal to 100-230I1gCcm-2day-l or
to 1-2.3 g C m -2 at 100% cover (Marsh 1970; Littler 1973a; Littler and Doty
1975; Wanders 1976b). The respiration rates in them varied within 40100I1gCcm-2day-l, and the P:M ratio within 2 to 4. So their net primary
production was relatively high: 40-150 I1g C m -2 day-I, thus providing their
linear growth of 10-20 mm year-I, which was comparable with the growth
rates of massive corals (Agegian 1981). The diurnal course of photosynthesis
in red Corallinaceae appeared to be resembling that in reef corals (Wanders
1976b; ct. Sects. 8.4, 9.1). The ratio of photosynthesis production per day to
that per 1 h in coralline algae was 9-11 (Wanders 1976b), while our
estimates for the periphytonic communities were within 9-10.5 (Sorokin
1986a). Having these an average value of 9.6, we use it for the recalculation
of daily photosynthesis rates for generalizations given in Table 4.18.
The compensation point of gross photosynthesis and respiration, when its
net production is zero in diurnal balance was attained in the coralline algae
at a very low illumination: 1-2.5 x 10 3 1x, that is 1-3% of midday PARS
(photosynthetically active radiation penetrated under the water surface).
This level of illumination happens to reign in transparent oceanic waters
(20-40 m Sechi disk visibility) at depths of 60-80 m. On outer reef slopes
off the Marshall I. the compensation point in coralline algae was found at a
depth of -80 m (Marsh 1970). The light saturation point of photosynthesis
in coralline algae was usually attained at 7-9 klx (Marsh 1970; Wanders
1976b; ct. Fig. 4.6). About the same level of saturation light intensity was
recorded in other reef macrophytes: 9-11 klx (ct. Fig. 4.7). Thus, coralline
algae are adapted also to a high level of illimination.
Associations of reef thallomic macrophytes have an extremely high level
of gross primary production - up to 1O-12gCm- 2 day-l (Tables 4.14,4.18).
This high level of communitary photosynthesis is provided by the high
photosynthesis rates of individual plants, which in most macrophytes is
2-4I1g02g-1h-l, reaching in some of them even 10 I1g 0 zg-l (Table
14.19). The lower values of gross photosynthesis, calculated per gram dry
weight, are peculiar to the calcareous thallomic algae, like Halimeda or
Penicillus, because their thalloms are loaded with the inert calcareous
skeletal material. But calculated per surface of thalloms, the rate of
photosynthesis in Halimada, for example, is twice as high as in coralline
algae. The coefficient of specific production (PIB) in Halimeda is around
0.07 (Drew and Abel 1983). The green calcareous alga Penicillus produces
Benthic Microftora, Periphyton and Plant Associations
The primary production of benthic plant associations was measured in
different individuals of their common species (Marsh 1970; Quasim and
Bhattathiri 1971; Wanders 1976b; West and Larcum 1983; Titlyanov et al.
1983b, 1985; Morrissey 1985) as well as in their associations inhabiting
different reef zones (Odum and Odum 1955; Marsh 1970, 1974; Wanders
1976b; Odum et al. 1959; Murphey and Kremer 1983; Littler 1979). The 14C
and oxygen release methods were employed (ct. Sect. 10.1). In crustose
coralline algae the gross photosynthesis varies within 1O-20I1gCcm-2h-l
(0.03-0.06I1g 02cm-2h-1), which is equal to 100-230I1gCcm-2day-l or
to 1-2.3 g C m -2 at 100% cover (Marsh 1970; Littler 1973a; Littler and Doty
1975; Wanders 1976b). The respiration rates in them varied within 40100I1gCcm-2day-l, and the P:M ratio within 2 to 4. So their net primary
production was relatively high: 40-150 I1g C m -2 day-I, thus providing their
linear growth of 10-20 mm year-I, which was comparable with the growth
rates of massive corals (Agegian 1981). The diurnal course of photosynthesis
in red Corallinaceae appeared to be resembling that in reef corals (Wanders
1976b; ct. Sects. 8.4, 9.1). The ratio of photosynthesis production per day to
that per 1 h in coralline algae was 9-11 (Wanders 1976b), while our
estimates for the periphytonic communities were within 9-10.5 (Sorokin
1986a). Having these an average value of 9.6, we use it for the recalculation
of daily photosynthesis rates for generalizations given in Table 4.18.
The compensation point of gross photosynthesis and respiration, when its
net production is zero in diurnal balance was attained in the coralline algae
at a very low illumination: 1-2.5 x 10 3 1x, that is 1-3% of midday PARS
(photosynthetically active radiation penetrated under the water surface).
This level of illumination happens to reign in transparent oceanic waters
(20-40 m Sechi disk visibility) at depths of 60-80 m. On outer reef slopes
off the Marshall I. the compensation point in coralline algae was found at a
depth of -80 m (Marsh 1970). The light saturation point of photosynthesis
in coralline algae was usually attained at 7-9 klx (Marsh 1970; Wanders
1976b; ct. Fig. 4.6). About the same level of saturation light intensity was
recorded in other reef macrophytes: 9-11 klx (ct. Fig. 4.7). Thus, coralline
algae are adapted also to a high level of illimination.
Associations of reef thallomic macrophytes have an extremely high level
of gross primary production - up to 1O-12gCm- 2 day-l (Tables 4.14,4.18).
This high level of communitary photosynthesis is provided by the high
photosynthesis rates of individual plants, which in most macrophytes is
2-4I1g02g-1h-l, reaching in some of them even 10 I1g 0 zg-l (Table
14.19). The lower values of gross photosynthesis, calculated per gram dry
weight, are peculiar to the calcareous thallomic algae, like Halimeda or
Penicillus, because their thalloms are loaded with the inert calcareous
skeletal material. But calculated per surface of thalloms, the rate of
photosynthesis in Halimada, for example, is twice as high as in coralline
algae. The coefficient of specific production (PIB) in Halimeda is around
0.07 (Drew and Abel 1983). The green calcareous alga Penicillus produces