Effects of Ocean Currents in the Western Pacific Ocean on Net-Phytoplankton Community Compositions

Abstract

Phytoplankton are known as important harbingers of climate change in aquatic ecosystems. This study investigated phytoplankton community structure in the western Pacific Ocean (WPO) in 2017 and revealed the spatial variability of phytoplankton in community composition and abundance, as well as their relationship to physical processes and environmental factors. The phytoplankton community was mainly composed of Dinophyta (221), followed by Bacillariophyta (105), Cyanophyta (4), and Chrysophyta (2). The cyanobacteria Trichodesmium were the dominants throughout the study period. Correlation analysis showed that dinoflagellates were mainly affected by temperature, while diatoms were significantly correlated with nutrients (silicate, phosphate, nitrite, nitrate). Phytoplankton was divided into five groups by cluster analysis, and the distribution of different groups was related to circulation and hydrological characteristics. In contrast, the highest abundance of diatoms and dinoflagellates was found in the New Guinea Coastal Current (NGCC) region, while the highest abundance of cyanobacteria was found in the Northern Equatorial Counter Current (NECC) region. Overall, we found that not only temperature and salinity, but also ocean currents and nutrients, influence the distribution of phytoplankton communities in the WPO.

Metabarcoding Analysis of Harmful Algal Bloom Species in the Western Pacific Seamount Regions

“…Of the small portion of the ASVs that could be annotated, our analysis revealed that Dinoflagellata was the most dominant group of phytoplankton in the Western Pacific seamount regions (Figure 3). This result was not totally surprising because Dinoflagellata was also previously reported to be the most dominant phyla in the Western Pacific regions [16,47], which may be due to environmental factors (including temperature) in these regions [16,48]. However, the relatively high abundance of species in Dinoflagellata estimated by ASVs cannot be simply interpreted as high cell density of these species because the relative abundance of ASVs highly depends on the copy numbers of rDNA genes.…”

Environmental Parameters And Phytoplankton Community Quality: Implications For Food Safety In Coastal Communities

“…Current velocity is an environmental parameter that affects phytoplankton. According to Chen et al, (2021), current velocity is very clearly its effect on phytoplankton distribus, not just nutrients, temperature and salinity. The movement of water masses due to currents certainly has an impact on the number of phytoplankton communities that are carried from one water to another.…”

Diatom distribution in Holocene sediments from the northern West Caroline Basin (western equatorial Pacific) and their environmental significance

“…The thermocline depth in the study area is 100-150 m. The surface seawater possesses high temperature, low salinity and low nutrient content, and is characterized by a two-layer system. A barrier layer separates the nutrient-rich deep water from the surface water (Vinogradov, 1981;Kobayashi and Takahashi, 2002;Chen et al, 2021).…”

“…The West Caroline Basin is located in the core of the Western Pacific Warm Pool, where the annual average sea-surface temperature is a minimum of 28°C (Wang et al, 2009;Qi et al, 2020;Chen et al, 2021). Sea temperature anomalies in the region influence climate change in the Asia-Pacific region and even the world by heating seawater and transporting radiant heat to the atmosphere (Long et al, 2021).…”