Planktonic community structure during a harmful bloom of Phaeocystis globosa in a subtropical bay, with special reference to the ciliate assemblages

Abstract

Planktonic community structure was investigated during outbreak of harmful Phaeocystis globosa bloom in a subtropical bay, the Maowei Sea, South China Sea. The phytoplankton assemblage was numerically dominated by colonial P. globosa, with its abundance ranging from 1.23 × 10(8) to 11.12 × 10(8) cells m(-3) and contributing nearly 90 % to the total abundance. Totally 66 mesozooplankton (>169 µm) and 19 ciliates species were recorded, with the densities ranged from 169 to 1633 ind m(-3) and 74 to 1118 cells L(-1), respectively. The dominant species for mesozooplankton were Copepoda (larvae), Bestiola sinicus, B. amoyensis, Macrura (larvae) and Acartia spinicauda, respectively. The ciliate assemblage was numerically dominated by Codonella rapa, Strombidium globosaneum and Mesodinium rubrum. During the bloom, P. globosa seemed to be negatively affected by the nutrient phosphate significantly (p < 0.05). However, no correlation between P. globosa and ciliate assemblage was detected, but P. globosa was negatively correlated with total biomass of mesozooplankton and abundance of B. sinicus (p < 0.05), suggesting that P. globosa was uncoupled from the grazing by both ciliates and mesozooplankton when appearing as colonies form. On the other hand, both positive and negative correlations among the dominant groups of mesozooplankton and ciliates were observed (p < 0.05) which possibly indicated that the predation of mesozooplankton upon ciliates might be strengthened during the Phaeocystis bloom and the complex effect also varied from species to species.

Progress in studies on the diversity and distribution of planktonic ciliates (Protista, Ciliophora) in the South China Sea

“…Predators also may play a role in controlling ciliate communities by top-down interactions (Gómez 2007;Sinistro 2010). In Maowei Bay of the SCS, both positive and negative correlations among the dominant groups of mesozooplankton and ciliates were observed, suggesting that the different ciliates were preferred by selected mesozooplankton species and the predation effects of mesozooplankton on ciliates were taxon-specific (Liu et al 2015a).…”

“…Rarely have they estimated the roles of biotic factors in their community structuring. As an intermediate link in energy transfer within the microbial food web, the ciliate community can also be effected by their preys and predators (Li et al 2016;Liu et al 2015a). To reveal the driving mechanism of distribution of ciliate in the SCS, stud-ies should be conducted that combine the effects of the abiotic and biotic factors on ciliates.…”

Phylogenetic Responses of Marine Free-Living Bacterial Community to Phaeocystis globosa Bloom in Beibu Gulf, China

“…For decades, blooms of P. globosa have occurred frequently in coastal regions of southern China during both winter and summer, greatly impacting local fishing, farming, and environmental health ( Wang et al, 2006 , 2010 ). Recently, P. globosa blooms have occurred frequently along the Beibu Gulf coast ( Liu et al, 2015 ; Qin et al, 2016 ; Xu et al, 2017 ), a historically important region for the economies of China and Vietnam because of the abundant and diverse marine resources ( Zheng et al, 2012 ). As such, there is a need to understand the impact of algal blooms and the mechanisms of their impact on ecosystem health.…”

Differential Gene Expression Supports a Resource‐Intensive, Defensive Role for Colony Production in the Bloom‐Forming Haptophyte, Phaeocystis globosa

“…; Liu et al. ). Decaying colonial biomass sinks and produces anoxic conditions, making Phaeocystis blooms detrimental to benthic fisheries and aquaculture (Desroy and Denis ; Peperzak and Poelman ; Spilmont et al.…”

“…Historically, colonial Phaeocystis blooms have been restricted to cold, high-latitude waters-P. globosa blooms in the English Channel and North Sea, P. pouchetii in the North Atlantic and Arctic, and P. antarctica in the Southern Ocean (reviewed in Schoemann et al 2005). In the last two decades, however, blooms have increasingly been reported in tropical and subtropical regions, including the subtropical N. Atlantic (Long et al 2007) and the subtropical and tropical South China Sea (Chen et al 2002;Doan-Nhu et al 2010;Liu et al 2015). Decaying colonial biomass sinks and produces anoxic conditions, making Phaeocystis blooms detrimental to benthic fisheries and aquaculture (Desroy and Denis 2004;Peperzak and Poelman 2008;Spilmont et al 2009).…”