Abundance of Calanus sinicus across the tidal front in the Yellow Sea, China

Abstract

The abundance of Calanus sinicus eggs, nauplii, copepodites and adults and chlorophyll a (Chl‐a) concentration were studied across tidal fronts in October 2000, and May and June 2001 in the Yellow Sea, China. The aim of the study was to evaluate the role of tidal fronts in the ecology of C. sinicus. The hydrographic tidal fronts were identified by the horizontal temperature gradient in the bottom layer and the temperature profiles across the fronts. The survey results showed that the concentration of Chl‐a was high in the vicinity of the fronts, particularly in spring and early summer. The abundance of C. sinicus eggs and nauplii was usually higher in the tidal fronts than in the adjacent areas. In May and June 2001, the abundance of copepodites and adults of C. sinicus peaked in the tidal front. In June 2001 and October 2000, many copepodites and adults were found in stratified region.

Trends of satellite derived chlorophyll-a (1997–2011) in the Bohai and Yellow Seas, China: Effects of bathymetry on seasonal and inter-annual patterns

“…The strong convection currents between coastal and offshore waters formed in some seasons can enhance the coastal nutrient transporting to offshore waters (Yuan and Hsueh, 2010;Yuan et al, 2008). Liu et al (2003) observed high primary and secondary production at Yellow Sea fronts and Huang et al (2010) found a good match between the position of major spawning grounds and the position of coastal fronts. The variability of Chla between coastal and offshore waters may be responding to the variations in frontal structures on seasonal and inter-annual time scales.…”

“…They follow the 50 m isobath and play key roles in nutrient transport and high productivity (Hickox et al, 2000;Huang et al, 2010;Liu et al, 2003). The strong convection currents between coastal and offshore waters formed in some seasons can enhance the coastal nutrient transporting to offshore waters (Yuan and Hsueh, 2010;Yuan et al, 2008).…”

Associations of large jellyfish distributions with temperature and salinity in the Yellow Sea and East China Sea

“…The mechanism of how aggregations of N. nomurai respond to the tidal front in the YS was undetermined. Their increased abundance could reflect the locally high chlorophyll a concentration and zooplankton biomass (Liu et al, 2003), or the interaction between frontal circulation and their swimming behavior (Purcell et al, 2000).…”

Why did the copepod Calanus sinicus increase during the 1990s in the Yellow Sea?

“…and Paracalanus spp., followed by Acartia spp., Labidocera spp., Corycaeus spp., and immature copepods. C. sinicus is one of the key copepod species in the Yellow Sea (Jang and Kim, 1998) and East China Sea ecosystems and comprises about 85% of the total zooplankton biomass in the Yellow Sea in the spring (Liu et al, 2003). Compared to small copepods such as P. indicus and A. omorii, C. sinicus was susceptible to active predation by anchovy and sardine (Uye et al, 1990).…”