Abstract
Food material (FM) derived from biochemical components (e.g., proteins, lipids, and carbohydrates) of phytoplankton can provide important quantitative and qualitative information of the food available to filter-feeding animals. The main objective of this study was to observe the seasonal and spatial variations of the biochemical compositions of phytoplankton and to identify the major controlling factors of FM as a primary food source in Jaran Bay, a large shellfish aquaculture site in South Korea. Based on monthly sampling conducted during 2016, significant monthly variations in the depth-integrated concentrations of major inorganic nutrients and chlorophyll a within the euphotic water column and a predominance (49.9 ± 18.7%) of micro-sized phytoplankton (>20 μm) were observed in Jaran Bay. Carbohydrates were the dominant biochemical component (51.8 ± 8.7%), followed by lipids (27.3 ± 3.8%) and proteins (20.9 ± 7.4%), during the study period. The biochemical compositions and average monthly FM levels (411.7 ± 93.0 mg m−3) in Jaran Bay were not consistent among different bays in the southern coastal region of South Korea, possibly due to differences in controlling factors, such as environmental and biological factors. According to the results from multiple linear regression, the variations in FM could be explained by the relatively large phytoplankton and the P* (PO43− − 1/16 × NO3−) and NH4+ concentrations in Jaran Bay. The macromolecular compositions and FM, as alternatives food source materials, should be monitored in Jaran Bay due to recent changes in nutrient concentrations and phytoplankton communities.
Highlights
Bays are important aquatic systems that provide food resources for fisheries and aquaculture since they provide habitats and prey for various marine organisms
The water samples (0.2 L) used for determining the dissolved inorganic nutrient concentrations were filtered through a 47 mm GF/F filters (0.7-μm pore size, Whatman, Maidstone, UK), and the filtrates were stored at −20 ◦ C for further analysis using an Auto Analyzer (Quaatro, Bran+Luebbe, Germany) at the National Institute of Fisheries Science (NIFS), Korea
The present study indicates that each nutrient concentration showed significant seasonal variations
Summary
Bays are important aquatic systems that provide food resources for fisheries and aquaculture since they provide habitats and prey for various marine organisms. The present study site, Jaran Bay, is one of the largest shellfish aquaculture regions for oysters and scallops in South Korea [2], and these filter-feeding oysters and scallops feed mainly on water-dwelling phytoplankton for their growth and reproduction [3,4]. Water 2020, 12, 3093 and are highly dependent on light conditions and quality [8,9,10], temperature [11], species composition [12,13] and nutrient availability [5,8,14]. Lee et al [5] reported that dissolved inorganic nitrogen loading from river discharge is a major factor that controls the photosynthetic biochemical compositions (e.g., carbohydrates, proteins and lipids) of phytoplankton in Gwangyang Bay
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
