Spatial-Temporal Variation of Characteristics of Plankton in a Seagrass Bed and an Adjacent Area of Bare Sand in Swan Lake, Rongcheng, China

Abstract

Seagrass beds are a typical coastal ecosystem. To understand the temporal and spatial variation characteristics of the plankton community structure in a Zostera marina seagrass bed and an adjacent area of bare sand in Swan Lake, Rongcheng City, Shandong Province, an investigation of plankton diversity and abundance, ecological characteristics of the seagrass bed, and key environmental factors in the Z. marina seagrass bed and its adjacent bare sand area was conducted in February, May, August, and November in 2019. Canonical correspondence analysis (CCA) and redundancy analysis (RDA) were used to explore the influence of environmental factors on the diversity of plankton species. The results showed that there were 38 species of phytoplankton, belonging to 25 genera and three phyla, among which diatom species were the most abundant (89.4%), followed by dinoflagellates (7.8%). A total of 18 species of zooplankton and three species of larvae were identified (mainly crustaceans: 71.4%), and the number of plankton species was the highest in November. The annual average abundance of phytoplankton and zooplankton in the seagrass bed was 5.4×104 cells/m3 and 1.6×104 ind./m3, respectively, which were 1.4 times and 1.5 times higher than those in the bare sand area. The CCA and RDA analyses showed that the dominant plankton species in the seagrass bed were significantly correlated with water temperature, plant density, and biomass of seagrass beds, while the dominant plankton species in the bare sand area were mainly correlated with environmental factors such as water temperature, pH value, and ammonia nitrogen content. The results showed that the seagrass bed in Swan Lake supported a higher abundance and diversity of plankton compared with the bare sand area. This study provides baseline data for further elucidating the structure and function of the seagrass bed ecosystem.

Keywords

• seagrass bed
• phytoplankton
• zooplankton
• community structure
• environmental factors
• swan lake