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601.
Accurate determination of flushing time is crucial for maintaining sustainable production in fish culture zones(FCZs),as it represents the physical self-purification capability via tidal exchange with clean water in the outer sea.However,owing to the temporal and spatial complexity of the coastal flushing process,existing methods for determining flushing time may not be generally applicable.In this paper,a systematic method for determining the flushing time in FCZs is presented,in which bathymetry,runoff,tidal range and stratification are properly accounted for.We determine the flushing time via numerical tracer experiments,using robust 3D hydrodynamic and mass transport models.For FCZs located in sheltered and land-locked tidal inlets,the system boundary can be naturally defined at the connection with the open sea.For FCZs located in open waters,hydrodynamic tracking is first used to assess the extent of tidal excursion and thus delimit the initial boundary between clean water and polluted water.This general method is applied to all designated marine FCZs in Hong Kong for both the dry and wet seasons,including 20 sheltered FCZs(in semi-enclosed waters of Tolo Harbour,Mirs Bay,and Port Shelter) and 6 FCZs in open waters.Our results show that flushing time is the longest in inner Port Shelter(about 40 days in dry season),and the shortest for the FCZs in open waters(less than one week in dry season).In addition,the flushing time in dry season is commonly longer than that in wet season:20%~40% for most well-sheltered FCZs;2.6~4 times for the others.Our results indicate a positive correlation between the flushing time and distance to open boundary,supporting the view that the flushing time of a FCZ is closely related to its location.This study provides a solid basis for mariculture management such as the determination of carrying capacity of FCZs. 相似文献
602.
Sangheon Yi Chang-Gyun Han Keun-Chang Oh In Sun Seo Dongwook Kim Jaeyoung Lee Min Han Hanwoo Choi Jaesoo Lim Sujeong Park Chang-Pyo Jun Taesop Cho 《第四纪科学杂志》2022,37(1):100-113
We comprehensively analyzed sediments obtained from an archeological excavation. A trench sediment profile of Maedun Cave (MC), South Korea, was analyzed geoarchaeologically. Multi-proxy analyses (palynomorphs, grain size, magnetic susceptibility, animal bones and artifacts) reflected the vegetation, hydroclimate and lives of prehistoric people at Marine Isotope Stage (MIS) 3 (ca. 40–30k cal a bp ) in the early Late Paleolithic. The palynoflora consisted of pollen and non-pollen palynomorphs. Under the air-circulation system in the cave, anemophilous pollen flowed in during the day, whereas waterborne pollen and spores, and freshwater algae, were transported by flooding during the summer monsoon rainy season. Mixed conifer and deciduous broad-leaved forest with an understory of pteridophytes flourished around the north-east central Korean Peninsula during MIS 3. Freshwater algae and grass pollen records may reflect precipitation intensity. It is assumed that they had flowed in during flooding caused by high precipitation during the enhanced East Asian summer monsoon, corresponding to Dansgaard–Oeschger (D/O) events 5 and 8 of δ18O GISP2 and Hulu Cave. The prehistoric people hunted herbivorous animals in the area around MC and sheltered inside it seasonally. They also used the grains of oats growing near the dwelling as a source of food. 相似文献