Primary production by phytoplankton in the territorial seas of the Republic of Korea

Abstract

The primary production (PP) by phytoplankton in marine ecosystems is essential for carbon cycling and fueling food webs. Hence, estimating the PP in the territorial sea of each country is a necessary step to achieving carbon neutrality. To estimate the PP in the territorial sea of the Republic of Korea from 2005 to 2021, we analyzed various physiochemical parameters, such as sea surface temperature (SST), Secchi depth, and concentrations of chlorophyll-a and nutrients in the seas of five regions, including the East Sea, West Sea, western South Sea, eastern South Sea, and the waters off Jeju Island. During the 17-year study period, the SST tended to increase, while the nutrient concentrations declined, except in the Jeju area. Overall, the PP did not show a specific temporal trend, but daily PP in the western South Sea was the highest among the five regions. Moreover, the maximum PP in the Korean territorial waters (76,450 km2 ) was estimated at 11,227 Gg C y-1, which accounts for 0.03% of the global PP. The results may give insights into a better understanding of the PP, further resource utilization, and environmental sustainability in the studied region.

Environmental Factors Influencing Annual Changes in Bycatch per Unit Effort of Delphinus delphis around Their Main Hotspot in Korean Waters

“…Primary production is a biological factor that drives the habitat use of cetaceans. In general, primary production in marine ecosystems forms an essential part of food webs [54]. Primary production serves as the foundation of zooplankton and pelagic fish production, which can lead to feeding aggregation of cetaceans, resulting in the formation of their coastal foraging hotspots [55,56].…”

Patterns of the relationship between the Secchi disk depth and the optical characteristics of water in the Neva Estuary (Baltic Sea): the influence of environmental variables

“…The simplest method for assessing water transparency involves visually determining the depth at which the white Secchi disk becomes invisible to the observer (D sd ). This method, originally proposed in the mid-19th century by Secchi (1864), is included in various reference indicators for characterizing the environmental quality of natural waters (Aas et al, 2014) and is widely employed to detect and monitor eutrophication (Fleming-Lehtinen and Laamanen, 2012;Jacobs et al, 2020;Lim and Jeong, 2022;Roy and Das, 2022;Guo et al, 2022b). It has also been included in the widely used metric Trophic State Index (TSI), which can be calculated from both chlorophyll a concentration and Secchi disk depth (Carlson, 1977).…”

Feeding by common heterotrophic protists on the mixotrophic dinoflagellate Ansanella granifera (Suessiaceae, Dinophyceae)

“…Dinoflagellates are ubiquitous and one of the major components of marine ecosystems (Taylor et al 2008, Stern et al 2010, Kang et al 2019b. They play diverse ecological roles in marine food webs as primary producers, predators, prey, symbiotic partners, and parasites (Coats 1999, Hansen 2011, Stoecker et al 2017, LaJeunesse et al 2018, Lim and Jeong 2022. They have three trophic modes: autotrophy, mixotrophy (i.e., autotrophy + heterotrophy), and heterotrophy (Stoecker 1999).…”