INTRODUCTION
Over the last several decades, the world’s ocean and inland waters have
been experiencing enormous blooms of various kinds of micro- and
macro-algae and zooplankton, which have caused severe environmental and
economic losses. The most reported blooms in scientific papers and media
include cyanobacteria (e.g., Shi et al., 2017; Huisman et al., 2018),
dinoflagellates (e.g., Glibert et al., 2008, 2009; Zhou et al., 2008),
Sargassum (e.g., Schell et al., 2015; Wang et al., 2019), Ulva (e.g.,
Smetacek and Zingone 2013; Wang et al., 2015), jellyfish (e.g.,
Richardson et al., 2009; Jackson et al., 2001; Sun et al., 2015), andAcetes chinesis (Zeng et al., 2019). These blooms are widespread
and recurrent and have been attributed to eutrophication as well as
altered environmental conditions due to climate change and anthropogenic
activities (e.g., Anderson et al., 2002; Edwards et al., 2006; Heisler
et al., 2008).
Creseis acicula (Rang 1828) is a pteropod species, which
widespread in the world oceans and prefers warm waters, particularly in
the upper layers of the ocean ranging from 50°N-40°S (Albergoni, 1975).
Outbreaks of C. acicula were found in Indian seas (Krishna
Murthy, 1967; Sakthivel and Haridas, 1974; Peter and Paulinose, 1978;
Pillai and Rodrigo, 1984; Naomi, 1988), Mediterranean sea (Burgi et al.,
1962; Albergoni, 1975; Kokelj et al., 1994), Japan sea (Nishimura, 1965;
Morioka, 1980), and Gulf of Mexico (Hutton, 1960), occurring during the
1960s to 1990s. The last report of C. acicula bloom was in 1990
in the Mediterranean sea (Kokelj et al., 1994). Since the 1990s, for
thirty years, there has not been a single record of its outbreak
worldwide, until mid-June 2020, when a sudden outbreak happened in Daya
Bay, South China Sea (Fig. 1, 3). This bloom of C. acicula was
first observed on June 12, 2020, and persisted into July 2020. It has
caused losses to local industry and tourism, particularly the Daya Bay
Nuclear Power Plant (DNPP) built on the southwest shore, with highly
concentrated C. acicula disrupting the cooling system. Both
government and public attached great importance to this bloom, since it
has poses a potential threat to the normal operation and safety of DNPP.
Here we present a briefing of this unusual outbreak by summarizing our
observations of the bloom and its associated environmental conditions to
provide a big picture of this rare zooplankton bloom. This report would
facilitate further investigations and advocate attention to possible
recurrent aggregation of C. acicula and other organisms in the
ocean, particularly in the context of global warming.