Temporal variability in physicochemical properties, phytoplankton standing crop and primary production for 7 years (2002-2008) in the neritic area of Sagami Bay, Japan

• Published in: Journal of oceanography Vol. 67; no. 1; pp. 87 - 111
• Main Authors: Ara, Koichi, Yamaki, Koh, Wada, Keisuke, Fukuyama, Satoshi, Okutsu, Takeshi, Nagasaka, Sadao, Shiomoto, Akihiro, Hiromi, Juro
• Format: Journal Article
• Language: English
• Published: Japan Japan : Springer Japan 01.02.2011; Springer Japan; Springer Nature B.V
• Subjects: Biogeochemistry; Brackish; Continental slope; Deep water; Dissolved inorganic nutrients; Dissolved oxygen; Earth and Environmental Science; Earth Sciences; Freshwater; Freshwater & Marine Ecology; Marine; Nutrients; Oceanography; Original Article; Particulate matter; Physicochemical properties; Phytoplankton; Plankton; Primary production; Sagami Bay, Japan; Salinity; Seasonal variations; Water depth; INW, Japan, Honshu, Kanagawa Prefect., Sagami Bay; INW, Japan Sea, Oyashio Water; INW, Pacific, Kuroshio Water; INW, Japan, Honshu, Tokyo Bay; Dissolved inorganic nutrients; Sagami Bay, Japan; Particulate matter; Physicochemical properties; Primary production
• ISSN: 0916-8370; 1573-868X
• DOI: 10.1007/s10872-011-0010-y

Seasonal and interannual variations in physicochemical properties (i.e., temperature, salinity, dissolved oxygen and dissolved inorganic nutrients), chlorophyll a (Chl-a), particulate carbon and nitrogen (PC and PN, respectively), and primary production were investigated in the neritic area of Sagami Bay, Kanagawa, Japan, from January 2002 to December 2008. These abiotic/biotic variables, except for NH₄ ⁺-N, repeated similar seasonal variations for all 7 years. On the basis of the analysis of data obtained on 167 sampling dates, depth-integrated primary production in this water can be easily estimated from Chl-a at the surface using the regression equations obtained in the present study. Intermittently high values of dissolved inorganic nutrients, Chl-a, PC, PN and primary productivity at the surface during the summer stratified period were induced by high freshwater discharge from the rivers after rainfalls and by the expansion of nutrient-rich Tokyo Bay Water. Temperature, salinity and dissolved inorganic nutrients showed drastic variations within a scale of a few days and/or weeks, and these variations were related to sea levels that represent the intrusion of the Kuroshio Water, Intermediate Oyashio Water or deep water from the continental slope. However, there was no consistent trend in the variations in Chl-a, PC, PN and primary production due to the complex effects of these waters.