Seasonal variations of particle fluxes in the northeastern equatorial Pacific during normal and weak El Niño periods

Abstract

and normal conditions were observed in the remaining periods. The normal period was divided into two seasons based on the cycles of environmental properties in the surface ocean: cold (December-May) and warm (JuneNovember) season. During the normal period, the total mass flux was 1.7 times higher in the cold season than in the warm season. Particularly, the CaCO 3 flux was nearly three times higher in the cold season. The enhanced CaCO 3 flux in the cold season was attributed to an increased foraminiferal flux, which may have influenced the seasonal variability of the total mass flux at the KOMO station. The enhanced foraminiferal flux during the cold season may have been caused by the environmental changes of the surface ocean in response to wind-driven mixing resulting in supply of subsurface nutrient-enriched water. Particle fluxes during the weak El Niño period were lower by 30% than those during the normal period, which was consistent with previous findings in the central and eastern equatorial Pacific.

Evaluation of Resuspended Sediments to Sinking Particles by Benthic Disturbance in the Clarion-Clipperton Nodule Fields

“…In general, high total mass fluxes (38 mg m À2 day À1 on average, n ¼ 45) were observed between December and May, whereas low values (16 mg m À2 day À1 on average, n ¼ 41) were observed between June and November ( Figure 2a). This seasonal variability correlates with the migration of the ITCZ (Kim et al 2010(Kim et al , 2011. Interannual variability in total mass flux in the CCZ was closely related to the ENSO cycle (Dymond and Collier 1988;Honjo et al 1995;Kim et al 2011Kim et al , 2012.…”

“…Korea Institute of Ocean Science & Technology (KIOST, formerly known as KORDI) has completed a number of studies in the manganese nodule fields of the CCZ since 1997, including examination of the abundance of manganese nodules, deep-sea environmental properties, and particle fluxes ( Figure 1) (Jeong et al 1996;Jung et al 2001;Hyun and Yang 2005;Kim et al 2010Kim et al , 2011Kim et al , 2012. In general, meteorological and hydrographic conditions at Station KOMO (Korea Ocean Research & Development Institute Long-term Monitoring Station: 10 30 0 N, 131 20 0 W; ca.…”

“…In general, meteorological and hydrographic conditions at Station KOMO (Korea Ocean Research & Development Institute Long-term Monitoring Station: 10 30 0 N, 131 20 0 W; ca. 5005 m water depth), such as wind speed, sea surface temperature (SST), sea surface salinity (SSS), and mixed layer depth are largely influenced by the meridional fluctuation of the ITCZ between 4 N during the winter-spring period (December-May), and 11 N through the summer-fall period (June-November) (Donguy and Meyers 1996;Amador et al 2006;Kim et al 2010Kim et al , 2011. Being located in the equatorial Pacific, the interannual variation of environmental properties is also directly influenced by the ENSO cycle (Dymond and Collier 1988;Honjo et al 1995;Kim et al 2011).…”

“…However, as noted by Parthiban (2000), the difference in particle flux alone between the two periods was insufficient to differentiate between the primary flux from the overlying water column and the resuspended particle flux. In the CCZ of the northeastern equatorial Pacific, particle flux shows large natural variability due to the seasonal migration of the intertropical convergence zone (ITCZ) and differing ENSO (El Niño-Southern Oscillation) conditions (Kim et al 2010(Kim et al , 2011(Kim et al , 2012. Therefore, it will be necessary to decouple the impact of mining from the natural variability in particle flux to quantitatively determine the contribution of resuspended particles derived from mining operations.…”

Evaluation of Similarity of Water Column Properties and Sinking Particles between Impact and Preserved Sites for Environmental Impact Assessment in the Korea Contracted Area for Manganese Nodule Development, NE Pacific

“…이에 따라 태평양 및 인도양에서 망간단괴 광구 탐사권을 보유한 일부 국가들은 자국의 광구지역 또는 그 주변지역에서 해양물리, 화학, 저서생물, 지질학적 특성 등의 환경연구와 심해퇴적물 교란기를 이용한 충격시험을 수행하였다 (Ozturgut et al 1980;Trueblood et al 1997;Chung et al 2001;Sharma et al 2001). 남동태평양에서 약 10년간 수행된 독일의 충격시험(Disturbance and Recolonisation Experiment, DISCOL)에서는 충격시험 이 후 중형저서동물인 선충류(Nematode)와 저서성 요각류 (Harpacticoida)의 개체수가 50% 정도 감소한 것으로 보 고되었다 (Schriever et al 1991(Schriever et al , 1992(Schriever et al , 2002Thiel 1992;Thiel et al 2001 )에 비해 약 3배 증가하였으며, 5일 후에 는 평상시기보다 1.5~2배 높게 측정되어 비교적 빠른 재 퇴적 과정을 제시하였고 (Parthiban 2000;Sharma et al 2001), 재부유 물질의 영향으로 충격시험 기간동안 초대형 저서동물의 개체수가 32% 정도 감소한 것으로 보고되었 다 (Rodrigues et al 2001 (Dymond and Collier 1988;Honjo et al 1995;Karl et al 1995;Chavez et al 1999;Kim et al 2010Kim et al , 2011Kim et al , 2012 (Talley 1991;Bostock et al 2010). Fig.…”