T

1000

Oyashio-transition Y = 10.54 X (n = 48, r2 = 0.877 )

4000

3000

2000

Kuroshio

Tosa Bay

Continental shelf ECS

2000

1500

4000

2000

1500

4000

1000

3000

2000

50 100 150 0 20 40

Standing stock of chlorophyll a (mgChl/m2)

50 100 150 0 20 40

Standing stock of chlorophyll a (mgChl/m2)

4000

3000

U 2000

1000

2000

Surface PAR (E/m2/day)

3000

2000

1000

3000

2000

1000

0 10 20 30 40 50 60 70

Figure 5: Plot of depth-integrated primary production (IPP) to (A) standing stock of chlorophyll a and (B) photosynthetically available radiation (PAR) on the surface in Oyashio-transition waters, Kuroshio waters, Tosa Bay, and continental shelf waters of the East China Sea.

The relationship between P^ (mgC/mgChl/day) and SST (T), expressed in exponential form as equation (1) (n — 175, r2 — 0.218), is similar to the theoretical maximum specific growth rate described by Eppley (1972); the highorder polynomial in equation (2) (n — 175, r2 — 0.227), parameterized using a nonlinear regression analysis of SYSTAT ver.10 (SPSS Inc, Chicago, IL, USA), is similar to a preliminary empirical model by Behrenfeld and Falkowski (1997).

5.3237 x 10"3T5

+ 0.10457T — 1.025T3 + 4.6278T2 - 6.3898T + 19.096.

Pfpt tended to increase with SST at temperatures between 0 and 30°C, with large variations above about 16°C (Fig. 6). Kuroshio waters, Tosa Bay, and ECS continental shelf waters had the same temperature regime, with Pfpt values that varied by a factor of more than three. The use of factors other than

< Japan and Okhotsk Seas v Oyashio-transition waters > Kuroshio waters □ Tosa Bay

° Continental shelf ECS

Figure 6: Relationship between sea surface temperature (SST) and maximum biomass normalized primary production (P^) around Japan. A solid line indicates an empirical function with high-order polynomial and a dashed line with exponential.

Figure 6: Relationship between sea surface temperature (SST) and maximum biomass normalized primary production (P^) around Japan. A solid line indicates an empirical function with high-order polynomial and a dashed line with exponential.

(A) Oyashio-transition (B) Kuroshio (C) Continental shelf ECS

(A) Oyashio-transition (B) Kuroshio (C) Continental shelf ECS

Figure 7: Relationship of water-column light utilization index C to total daily incident PAR in Oyashio-transition waters (A), Kuroshio waters (B), and continental shelf waters of the East China Sea (C).

SST is expected to improve algorithms to estimate primary productivity using Pfpt values.

Falkowski (1981) proposed a water-column light-utilization efficiency index, C (m2 mgC/mgChl/E), defined as:

where IPP is primary production integrated from the surface to the base of the euphotic zone over a day, IB is the chlorophyll-based biomass integrated from the surface to the base of the euphotic zone, and IE0 is PAR incident on the surface integrated over a day. Falkowski and Raven (1997) mentioned that C increased as PAR decreased on the basis of analysis of data for hundreds of stations in the world's oceans. We proposed empirical relationships between C and PAR for estimating IPP in Oyashio-transition waters, Kuroshio waters, and ECS continental shelf waters (Fig. 7), based on the standing stock of chlorophyll a (integrated from the surface to the base of the euphotic zone) and sea surface PAR (integrated over a day).

Was this article helpful?

0 0

Post a comment