Temporal and spatial variations in the distribution of macroalgal communities along the Yantai coast, China

Abstract

To explore the impact of environmental variables on macroalgal communities, their temporal and spatial distributions were examined along the Yantai coast, China between April 2010 and March 2011. Macroalgae sampling was conducted monthly at four sites along the coast: Jiahe River estuary, Zhifu Island, Fisherman's Wharf, and Yangma Island. The species composition and abundance, and their relationship with environmental variables were assessed. Along the Yantai coast, 35 macroalgae species were identifi ed, including 24 Rhodophyta spp., 7 Chlorophyta, and 4 Phaeophyta spp. Highest species numbers were recorded in the summer at all sampling sites, except in the Jiahe River estuary. Macroalgae biomass was the greatest in the summer. Year-round, the highest species number and dry biomass recorded at Fisherman's Wharf and Yangma Island was attributed to the substrate type. In summer, Ulva pertusa Kjellman was the dominant species identifi ed along the Yantai coast, which indicates a risk of macroalgae blooms. Our results show that seawater temperature and nutrients appear to signifi cantly affect the temporal and spatial patterns of macroalgal abundance along the Yantai coast. The effects of environmental variables on the macroalgae on the Yantai coast need further study.

Selection of effective macroalgal species and tracing nitrogen sources on the different part of Yantai coast, China indicated by macroalgal δ15N values

“…The higher TN of algal tissue of Rhodophyta and Chlorophyta species compared to Phaeophyta species at the four sites along the Yantai coast showed different nitrogen storage between phyla. This is supported by the report that species of Rhodophyta and Chlorophyta had a competitive advantage (Kraufvelin et al, 2010;Han and Liu, 2014). Some filamentous and foliose macroalgal groups showed elevated N content and lower C:N ratios as characterized by simplest structure and/or a higher surface area (Ochoa-Izaguirre and Soto-Jiménez, 2015), which explained U. pertusa in our study showed higher tissue TN at S2, S3 and S4.…”

“…Thus, it was supposed that the growth and absorption of nitrogen of algae at S2, S2 and S4 were limited by PO 4 -P concentrations. This supposition get support from results of Han and Liu (2014) which stated that growth of macroalgae at S1, S3 and S4 were affected by PO 4 -P concentration. Impacts of metabolism to nitrogen and carbon in macrogalgae are species-specific owing to different storage capacity and nutrient requirements for growth (Hanisak and Harlin, 1978;Larned, 1998;Deutsch and Voss, 2006).…”

“…It is a typical temperate region with surface sea temperatures of approximately 2 to 3°C in winter and 24 to 28°C in summer and surface sea salinities generally of 29.0 to 31.5 psu due to river input along the coastline (Zhuang and Chen, 2003). Abundant macroalgae are distributed in the littoral zone, including Rhodophyta (e.g., Ceramium, Gelidium), Chlorophyta (e.g., Ulva) and Phaeophyta (e.g., Colpomenia) (Zhuang et al, 2010;Han and Liu, 2014), which makes it possible to use the δ 15 N values in macroalgal tissue to trace nitrogen sources along the coastline.…”

“…Over the last three decades, increased nitrogen loadings along the coastline, resulting from anthropogenic activities (e.g., agriculture, marine aquaculture, factorial, and sewage discharge), have distinctly degraded the health of the coastal ecosystem (Zhou et al, 2006;Wang et al, 2012). Frequent micro-and macroalgal blooms in coastal water have threatened the security of marine aquaculture and tourism (Hao et al, 2011;Liu et al, 2013;Han and Liu, 2014). Therefore, controlling nitrogen loading and establishing effective management policies are urgent matters.…”

Polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants (aBFRs) in sediments from four bays of the Yellow Sea, North China

“…Compared to Dalian Bay and Jiaozhou Bay, Taozi Bay and Sishili Bay are relatively open and mainly influenced by coastal currents. The mean water depths of these two bays are <20 m. Sishili Bay receives nutrients from marine aquaculture operations, wastewater inputs, and harbor pollution (Han and Liu, 2014). Dalian is a major industrial and harbor city with a population of 2.7 million people in an urban area of 2400 km 2 .…”