58
Reef Environments
Table 2.5. Phosphate flows between components of bottom biotopes and water column
during daylight; Kp - initial P04-P content in water, ~mol 1-1; Ac - uptake flow; Aerelease flow; ±A, - net changes of P04-P content in water (After Sorokin 1990c)
Component
Kp
Flows of P04-P
~g Pkg- I h- I
mg Pm- 2 day-1
Ac
Ac
A,
Ac
A,
Piece of reef-flat rock, covered with
1.00
84.3
27.3
-57.0 10.1
-6.8
periphyton
0.35
18.2
15.1
-3.1
2.2
-0.4
Coral rubble from reef flat covered
1.0
59.1
20.1
-38.4 11.3
-7.4
with periphyton
0.35
31.0
18.0
-13.0
3.7
-1.6
0.16
11.5
21.5
-10.0
1.4
+1.2
Dead branch of coral Stylophora
1.0
85.6
44.4
-41.2 18.5
-8.9
covered with periphyton
0.35
56.0
53.9
-2.1
12.1
-0.5
0.16
14.6
17.4
+2.8
3.2
-0.6
Living branch of the same coral
1.0
110.5
31.9
-78.6 15.9
-11.3
colony
0.35
51.7
28.8
-22.9 11.2
-4.9
0.16
12.6
11.4
-1.2
2.3
-0.2
Coral sand from leeward reef-flat
1.0
25.0
19.3
-5.7
4.8
-1.1
0.35
15.2
23.2
+8.0
2.9
+ 1.5
0.16
6.1
11.2
+5.1
1.2
+0.9
overgrowths over the flat rocks, dead coral colonies and rubble were
accomplished in aquaria. Studies of the P04-P exchange flows between the
coral sands and the water column were performed in situ in dark and light
plastic enclosures.
These experiments proved the existence of the above-mentioned
reciprocal flows of P04-P from and into the periphytonic communities
(Table 2.5, Fig. 2.10). The same was recorded for coral sands. Both these
Ae
Fig. 2.10. Dependence of the consumption (Ac) and release (Ae) of P04-P (~g P kg- I h- I )
by coral Pocillopora damicarnis between rubble overgrown by periphyton and the water
column; for designations, cf. Fig. 2.9. (After Sorokin 1990c)