Oceanic nutrient supply and uptake by microphytobenthos of the Hichirippu Lagoon, Hokkaido, Japan
[摘要] ABSTRACT: We conducted field surveys to determine spatio-temporal variations in the water quality (including inorganic nutrient concentration) of a coastal lagoon, Hichirippu Lagoon (3.56 km2), in Hokkaido, Japan. During a typical supply period (winter), a 24 h continuous survey was conducted to evaluate nutrient supply from the open ocean and examine nutrient utilization by microphytobenthos (MPB) based on the mass balance of a biophilic element. During February 2008, the majority of NO3+NO2-N was supplied from the open ocean, and the dissolved inorganic nitrogen (DIN) budget was 3.25 kmol N d1. In March 2008, the total amount of organic nitrogen was 39.0 to 588 kmol N for MPB in the surface sediment (depth, 0.5 cm). Assuming that MPB in the surface sediment used all NO3+NO2-N input (3.93 kmol N d1), their temporal division rate (NO3+NO2-N uptake/total amount of MPB) would be 0.01 to 0.10 d1. Here the annual DIN budget was estimated to be 258 kmol N yr1, which mainly depended on MPB-fixed oceanic DIN during winter.
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[效力级别] [学科分类] 海洋学与技术
[关键词] Microphytobenthos;Coastal ecosystem;Nutrient cycles;Dissolved inorganic nutrients;Mass balance [时效性]
