Abstract. This study reports the most comprehensive data set thus far of surface seawater pCO 2 (partial pressure of CO 2 ) and the associated air-sea CO 2 fluxes in a major ocean margin, the East China Sea (ECS), based on 24 surveys conducted in 2006 to 2011. We showed highly dynamic spatial variability in sea surface pCO 2 in the ECS except in winter, when it ranged across a narrow band of 330 to 360 µatm. We categorized the ECS into five different domains featuring with different physics and biogeochemistry to better characterize the seasonality of the pCO 2 dynamics and to better constrain the CO 2 flux. The five domains are (I) the outer Changjiang estuary and Changjiang plume, (II) the Zhejiang-Fujian coast, (III) the northern ECS shelf, (IV) the middle ECS shelf, and (V) the southern ECS shelf. In spring and summer, pCO 2 off the Changjiang estuary was as low as < 100 µatm, while it was up to > 400 µatm in autumn. pCO 2 along the Zhejiang-Fujian coast was low in spring, summer and winter (300 to 350 µatm) but was relatively high in autumn (> 350 µatm). On the northern ECS shelf, pCO 2 in summer and autumn was > 340 µatm in most areas, higher than in winter and spring. On the middle and southern ECS shelf, pCO 2 in summer ranged from 380 to 400 µatm, which was higher than in other seasons (< 350 µatm). The areaweighted CO 2 flux on the entire ECS shelf was −10.0 ± 2.0 in winter, −11.7 ± 3.6 in spring, −3.5 ± 4.6 in summer and −2.3 ± 3.1 mmol m −2 d −1 in autumn. It is important to note that the standard deviations in these flux ranges mostly reflect the spatial variation in pCO 2 rather than the bulk uncertainty. Nevertheless, on an annual basis, the average CO 2 influx into the entire ECS shelf was 6.9 ± 4.0 mmol m −2 d −1 , about twice the global average in ocean margins.

[1] During the 1997 -1998 El Niño event, the average sea surface temperature (SST) in the Taiwan Strait (TWS) in the winter was $1.4°C higher than that of the winter climatological mean. The areal ratio of the warm water (!2°C above the regional mean) to the cold water (!2°C below the regional mean) in the TWS increased by 25% while the area of the eutrophic water (chlorophyll a >1 mg m À3 ) was halved. Field observations also indicate that the mixed layer in the TWS became more nutrient-poor during this winter. These observations are consistent with a diminished advection of the cold and eutrophic Zhe-Min Coastal Water, and, concomitantly, an expansive intrusion of the warm and oligotrophic South China Sea Warm Current/ Kuroshio Branch Water to the TWS as the northeast monsoon was weakened. Thus, El Niño events potentially can have significant ecological impacts on the TWS.

A correction of the imaginary frequency is necessary for 2 TS SO in Figure 1 of this paper. The old 2 TS SO shown there (located with the option opt = loose in Gaussian 03) and the new one (reoptimized with the default convergence criterion; see also the Supporting Information) are both given below, along with their frequencies and relative energies (B3LYP/LACVP** level). The large imaginary frequency in the old structure was caused by the use of a loose geometry optimization criterion. The relative energies are almost identical, and mechanistic conclusions are not affected.

A novel organic-inorganic hybrid monocapped/bicapped Keggin structure [Co(II)(bpy)3]6(H2bpy)[(Co(II)bpy)2(PMo8(VI)Mo4(V)O40)]3 [(Co(II)bpy)(PMo8(VI)Mo4(V)O40)]·16H2O (bpy = 2,2'-bipyridine) was synthesized and shown to be an efficient visible light-driven catalyst for water oxidation.