Temporal and Spatial Distributions of Rotifers in Xiangxi Bay of the Three Gorges Reservoir, China

Abstract

The rotifer community exhibited a patchy distribution, with significant heterogeneity observed along the longitudinal axis. All rotifer communities could be divided into three groups, corresponding to the riverine, the transition and the lacustrine zone, respectively. IntroductionZooplankton heterogeneity and community structure at a range of spatial and temporal scales is an important focus of aquatic ecological research (CLARK et al., 2001). Studies on temporal variations in zooplankton distribution are common, but research on spatial patchiness has received relatively less attention. Zooplankton spatial distributions are as heterogeneous as those of terrestrial and aquatic plants and animals (FERNÁNDEZ-ROSADO and LUCENA, 2001). Now, it is a well-known phenomenon (SEDA and DEVETTER, 2000) and has been shown to be an ecologically important feature of freshwater ecosystems (PINEL-ALLOUL et al., 1999). The structure and composition of organisms and the spatial pattern of a community are of crucial importance for understanding ecosystem functioning (ROSENZWEIG, 1991;ROMARE et al., 2003) because they can affect ecosystem processes, functioning and stability (MAESTRE et al., 2005). Reservoirs are complex systems, considered as transitions between rivers and lakes. Several important differences between lakes and reservoirs are observed such as geological age, maximum depth location, shape and water retention time (STRAŠKRABA and TUNDISI, 1999). These differences are mostly pronounced in canyon-shaped reservoirs, which are spatially highly heterogeneous because of their relatively short retention times and longitudinal heterogeneity (MAŠÍN et al., 2003). A canyon-shaped reservoir presents three very distinct zones: the riverine zone, in the upper reservoir, which is subject to the influence of either the tributaries or river of origin; the transition zone, downstream from the reservoir, which functions as an intermediate river-lake ecosystem; and the lacustrine zone, located further downstream (MATSUMURA-TUNDISI and TUNDISI, 2005). These zones vary widely in flow and depth, making characterization of the reservoir more difficult than that of most natural lakes (BERNOT et al., 2004).The Three Gorges Reservoir of China (a newly impounded canyon-shaped reservoir), is a world-famous hydroelectric project (Fig. 1). This reservoir is undergoing a process of Figure 1. The location of Xiangxi Bay in China (above) and sampling stations (below).

Patterns of asynchrony for phytoplankton fluctuations from reservoir mainstream to a tributary bay in a giant dendritic reservoir (Three Gorges Reservoir, China)

“…Following the above point of view, the present study can take an applied perspective to the improvement of ecological observation programs for TGR and the reduction of long-term monitoring costs. Since TGR is one of the largest human-made lakes in the world, there has been much more attention paid to the potential change in the aquatic ecosystem after the impoundment of TGR (e.g., Cai and Hu 2006;Ye et al 2007;Shao et al 2008;Zhou et al 2009;Zhang et al 2010). Most aquatic researchers and TGR managers hope to infer ecological trends of the reservoir from the accumulation of local site-specific trends because it is very hard to carry out the full-scale observations in the giant dendritic reservoir.…”

Daily and vertical dynamics of rotifers under the impact of diatom blooms in the Three Gorges Reservoir, China

“…The diatom bloom in the Xiangxi Bay seemed to accelerate the densities of rotifers although with several days of lag. This indicates that phytoplankton is the primary food resource for rotifers (Guiral et al, 1994;Yoshida et al, 2003;Zhou et al, 2009). It has been reported that in spring the metabolism and production of zooplankton could be increased by the increasing food supply (Montagnes & Lessard, 1999).…”

Türkiye İçsuları için Yeni Bir Rotifer Türü

“…P. truncatum is reported as thermophilic specimen (Koste 1978), and its embryonic development occurs at high temperatures, and this period continues for a long time (Edmondson 1960). P. truncatum was reported from various areas in the world including; Russia (Telesh 1995), Canada (Swadling et al 2000), China (Lin et al 2003;Zhaou et al 2009 Kehayias et al 2008), and North America (Barbiero and Warren 2011), except Turkey which is located in Palearctic region. Also, it has been a subject of several studies (e.g.…”