Assessment of the Equatorial Indo Pacific Primary Production

In order to put in perspective how different areas contribute to the total PP of the equatorial Indo-Pacific, I designed six areas inspired from the oceanic biomes of (Longhurst, 1998). These areas are represented by the squares in Fig. 2. For each of these areas, the total amount of yearly primary production (TYPP) has been estimated using the map of PP estimates from satellite

W84-14GC

W84-14GC

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RC13-110

RC13-110

The Carbon Cycle Vertical

Figure 6: Variations of primary production estimates (solid line) in Core W84-14GC (upper panel) and Core RC13-110 (lower panel) compared with precession (Laskar, 1990) (doted line). Vertical lines represent Termination I and II.

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Figure 6: Variations of primary production estimates (solid line) in Core W84-14GC (upper panel) and Core RC13-110 (lower panel) compared with precession (Laskar, 1990) (doted line). Vertical lines represent Termination I and II.

MD97-2138

MD97-2138

Age (Ka)

MD97-2140

MD97-2140

Figure 7: Variations of primary production estimates (solid line) in Core MD972138 (upper panel) and Core MD972140 (lower panel) compared with precession (Laskar, 1990) (doted line). Vertical lines represent Termination I and II.

Figure 7: Variations of primary production estimates (solid line) in Core MD972138 (upper panel) and Core MD972140 (lower panel) compared with precession (Laskar, 1990) (doted line). Vertical lines represent Termination I and II.

Precession maximum

Precession maximum

Figure 8: Phase wheel diagram established using cross-Blackman-Tukey spectral analysis between all the PP and (black lines), 818O (grey lines) records and precession. A phase wheel can be read as a watch, time running clockwise, the "needles" make a full turn in 23 kyr; their size is proportional to their coherency. The inner grey circles represent the 80% (dark) and 90% (light) confidence level on coherency. The bars at the end of the "needles" represent the confidence (band width) of the phase. Because precession is season related, the different seasons are given inside the diagram.

Figure 8: Phase wheel diagram established using cross-Blackman-Tukey spectral analysis between all the PP and (black lines), 818O (grey lines) records and precession. A phase wheel can be read as a watch, time running clockwise, the "needles" make a full turn in 23 kyr; their size is proportional to their coherency. The inner grey circles represent the 80% (dark) and 90% (light) confidence level on coherency. The bars at the end of the "needles" represent the confidence (band width) of the phase. Because precession is season related, the different seasons are given inside the diagram.

imagery (Antoine et al., 1995). For each record ofPP, its average Holocene PP (PPh) value has been subtracted from all the PP values (PPs). These new values have been divided by the variance of the original record (PPv), and then multiplied by the total PP of the zone in which the records have been taken.

The new record of variations of total yearly production of each area (TYPPa) is given by the following equation:

In two areas two cores were studied. This was the case for Cores M49, M63, M40 and M38. The mean of cores M49 and M63, and M40 and M38 were used for the calculations presented above.

The sum of all the six different TYPPs provides the first estimate of the total yearly production of the low-latitude Indo-Pacific Ocean for the last

Ocean Productivity Latitude

Figure 9: Record of low-latitude Indo-Pacific primary production in Pg of carbon per year derived by adding the weighted variability of the different records. The weighing factor corresponds to the annual production of the area (see Fig. 2) where the core has been retrieved (solid line). The dotted line is the 8 8O stack of the cores used in that study.

Figure 9: Record of low-latitude Indo-Pacific primary production in Pg of carbon per year derived by adding the weighted variability of the different records. The weighing factor corresponds to the annual production of the area (see Fig. 2) where the core has been retrieved (solid line). The dotted line is the 8 8O stack of the cores used in that study.

180 kyr (Fig. 9). The importance of precession is clearly visible, but one cycle is missing at 115 kyr. This shows the strong weight of the eastern Pacific in that reconstruction, for which the precession cycle is not strongly marked. The obliquity signal is also strongly present. That figure shows the advance of PP on the 818O stack. The glacial/interglacial difference is of 3.5 Pg ( — 3.5 Giga tons) of carbon, which represents an increase of 50% of productivity of that area during the glacial time (MIS 2 and 6) versus interglacial time (MIS 1 and 5).

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