13
Carbon cycle
- - --
-
- - -
--
-
-
150
1 020
38 100
650
50
Deep ocean
Dissolved organic C
Labile
dissolved
organic C
Sediments
Ocean surface
Marine
biota
3
4
6
6
0.2
40
50
100
Figure 1: Carbon Cycle.
Oceans are crucial in the global
carbon cycle. It was here where life first evolved; they are
the source of our wealth and development. The living
oceans capture over half of all the Green carbon – the car-
bon bound by living organisms through photosynthesis.
Units of Carbon used. This report will use Tg C, but read-
ers will also see values for C and CO
2
, provided in a wide
range of formats. The following information may assist
in wider reading.
Definition: Measuring Carbon
1km
2
= 100ha
1 ton = 2,240lbs
1 (metric) ton = 1,000kg or 1x10
6
g
Blue carbon sinks capture CO
2
through photosynthesis
from the air and water and store it as carbon.
The rate of converting C to CO
2
is 44/12; i.e. 1 aton of C
is equivalent to 3.67t CO
2
Name
One thousand
One million
One billion
One trillion
Factor
10
3
10
6
10
9
10
12
10
15
Symbol
k (Kilo)
M (Mega)
G (Giga)
T (Tera)
P (Peta)
