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

Abstract

• Yantai coast was affected by three types of DIN sources.• Macroalgal species suitable or not for DIN source tracing were suggested; • TN and δ 15 N were affected by nutrient concentrations and the metabolic factors.• P instead of N limited the tissue N uptake in low nutrient concentration sites. G R A P H I C A L A B S T R A C Ta b s t r a c t a r t i c l e i n f o To determine the dominant nitrogen sources and select effective macroalgal species for monitoring eutrophication along the Yantai coast, the total carbon (TOC), total nitrogen (TN) and nitrogen stable isotope ratio (δ 15 N) in macroalgal tissue were analyzed in conjunction with environmental variables in seawater along the Yantai coastline. The ranges of macroalgal tissue δ 15 N values together with dissolved inorganic nitrogen (DIN) composition indicated that except for the atmospheric deposition, there were three dominant types of nitrogen sources along the Yantai coast, with the agricultural fertilizer usage and factorial wastewater input at the S1 (Zhifu Island coast), the sewage discharge at S2 (the Moon Bay coast), the sewage discharge together with aquaculture impacts at S3 (Fisherman Wharf coast) and S4 (the Horse Island coast). Macroalgal growth were not limited by DIN but limited by P at S2, S3 and S4. Macroalgal species suitable or not for DIN source tracing along the Yantai coast were discussed. For sites with low DIN concentration, many species of three phyla could be used for DIN sources tracing with Laurencia okamurai, Gloiopeltis furcata and Ulva pertusa being ideal species. For site with high DIN concentration, however, species of Rhodophyta were not suitable and only Scytosiphon lomentaria and Monostroma nitidium were chosen.

Changes in trophic characteristics of two fish species of Astyanax (Teleostei: Characidae) in response to aquatic pollution

“…Morrissey et al 2013, Pastor et al 2014, Baumgartner and Robinson 2016, and primary producers (e.g. MCclelland and Valiela 1998, Cole et al 2004, Wang et al 2016. Together, results of these studies, including ours, support the finding that high δ 15 N values are good indicators of anthropogenic stress in aquatic systems.…”

Stable isotopic evidence of nitrogen sources and C4 metabolism driving the world’s largest macroalgal green tides in the Yellow Sea

“…2 ). The overwhelming dominance of fluvial N transport to the Yellow Sea is corroborated by many papers 18 , 67 – 71 . Moreover, during warmer seasons in the Yellow Sea, vertical stratification is marked, as evident in sigma t and salinity profiles, constraining upwelling of deeper layers so that upward transport of heavy N may not be a dominant mechanism 66 .…”

“…Even in the open Yellow Sea, concentrations of dissolved inorganic nitrogen are 10–80 µM near the coast, and 0.7–5.8 µM offshore 7 . Other reports confirm that concentration of coastal dissolved inorganic nitrogen range 7.4–95 µM 18 and 1–15 µM offshore 10 . Such high concentrations of nitrogen must stimulate the onset and maintain the Ulva bloom.…”

“…One of the estimates from ref. 18 had an anomalous range of −6.7 to −1.3‰ and was not included in this entry.…”

Cultural Eutrophication Is Reflected in the Stable Isotopic Composition of the Eastern Mudsnail, Nassarius obsoletus

“…Although some previous reports have used nitrogen stable isotope ratios to apportion nutrient pollution sources between inorganic agricultural fertilizer and wastewater (Derse et al, 2007; Wang et al, 2016), other studies have interpreted δ 15 N enrichment in agricultural watersheds as a sign of nitrogen overenrichment (Wasson et al, 2017). Our study found no indication that agricultural watersheds were associated with lighter stable nitrogen isotope signatures, reflecting that of chemical fertilizers (δ 15 N ≈ 0) (Marion et al, 2005).…”