Two Production Stages of Coccolithophores in Winter as Revealed by Sediment Traps in the Northern South China Sea

Abstract

Coccolithophores, originating in the Late Triassic, are one of the most successful marine calcifying algae living in modern oceans. Coccoliths are the calcareous fossil remnants left in marine sediments after coccolithophores die. These calcite scales record the conditions of the surface ocean (e.g., primary productivity, seawater temperature, and carbonate chemistry) and are expected to be a promising subject in paleoceanographic and paleoclimatic studies. Hence, a comprehensive understanding of the ecology and phenology of living coccolithophores, as well as their interactions with other plankton groups, is needed to develop better constraints on their uses in paleoenvironmental studies. Here we show modern coccolithophore production through the coccolith fluxes from sediment traps at a ~500‐m water depth from 2013 to 2015 in the northern South China Sea. In addition to the expected seasonality of the coccolithophore production that occurs during winter seasons due to the strong water mixing induced by monsoon winds, a two‐stage mode for the coccolithophore production is also recognized in relatively “coastal” waters. The first stage includes the production of Gephyrocapsa oceanica in December, when the macronutrient inventory is built, and the second stage describes the growth of Emiliania huxleyi in late February with the depletion of silicate nutrients. This two‐stage mode originates from subtle differences in the nutrient assimilation ability between the two species. In addition, coccolithophore production is significantly influenced by the decadal oceanic events (i.e., El Niño) in the northern South China Sea.

Marine Paleoproductivity From the Last Glacial Maximum to the Holocene in the Southwestern Atlantic: A Coccolithophore Assemblage and Geochemical Proxy Perspective

“…(Toledo et al, 2016), making it a species with a signal that is difficult to deduce. Furthermore, as a cosmopolitan species, it may not indicate upwelling processes but is more typical of a stable regime, as observed in other studies (Andruleit and Rogalla, 2002;Jin et al, 2019).…”

“…Comparing our record to SSTs estimated by Lourenço et al (2016), we analyzed the same process described by Jin et al (2019), with E. huxleyi dominating the period with warm and stable water and Gephyrocapsa spp. with colder nutrient-rich (silicon) water of the CW (Figures 5C-F and Figures 6B-F).…”

“…However, they were separated into distinct ecological preferences, with E. huxleyi related to a more stable, warmer, and nutrient-poor water column associated with the upwelling relaxation stage and Gephyrocapsa spp. to colder water and higher nutrient availability associated with the early stages of the upwelling event (Ausín et al, 2018;Jin et al (2019) in the South China Sea also found that Gephyrocapsa spp. were dominant in coastal water associated with higher diatom production and increased silicon content, while E. huxleyi was associated with a regular nutrient regime with lower amounts of silicon.…”

Clumped isotopes in globally distributed Holocene coccoliths reveal their habitat depth

“…As for the Caribbean, mean annual primary productivity in the South China Sea is also low (Liu and Chai, 2009). Physical-biogeochemical modelling (Liu and Chai, 2009) and sediment trap studies (Jin et al, 2019) show that coccolithophores and other primary producers peak during winter-early spring (December-March), in response to the nutrient input driven by the East Asian Winter Monsoon. The large air pressure difference between the Siberian High and the Aleutian Low enhances wind intensity and consequently, water mixing and nutrient input (Tseng et al, 2005).…”

High‐Resolution Coccolithophore Morphological Changes in Response to Orbital Forcings During the Early Oligocene

“…Taken together, our results suggest that the larger size of coccolithophores during high-obliquity is attributed to the increased AMOC and Benguela upwelling. In contrast, smaller size is indicative of weakened AMOC, Benguela upwelling, and nutrient export during low obliquity (Figure8a).On the other hand, wind-driven mixing that brings nutrients from the ocean interior to the upper ocean could influence the ecology of the upper ocean, resulting in the seasonal growth of coccolithophores(Beaufort & Heussner, 2001;Beaufort et al, 2022;Hopkins et al, 2021;Jin et al, 2019;Renaud et al, 2002). This is also applicable to the study site because the west coast of South Africa also shows great obliquity-modulated seasonality in the late Quaternary(Chase, 2021;Dickson et al, 2010).…”