Assessment of bacterial biomass in the highly contaminated urban Nanming River, Guiyang, SW China

• 作者: Hao Xiao Hua-Yun Xiao Pan Wu
• 学科: 地球科学
• 关键词: δ13C δ15N Bacterial biomass N budget Nanming River
• 年，卷（期）: 2022,（4）
• 页码范围: 638-644
• 页数: 6页
• 语种: 英文
• DOI: 10.1007/s11631-017-0251-6

摘要

High anthropogenic N loads and abundant bacteria are characteristic of highly contaminated urban rivers. To better understand the dispersal and accumulation of bacteria, we determined contents and isotopic compositions of suspended particulate organic matter (SPOM) and bacteria in a highly contaminated urban river (the Nanming) and effluents in winter and summer of 2013. Relative to SPOM, bacterial biomass in the river was depleted in 13C and 15N and its C/N ratio was lower (δ13C: -33.2‰ ± 3.1‰; δ15N:-1.5‰± 1.2‰; C/N:4.8 ± 0.6), while effluents showed higher 13C and 15N contents and C/N ratios (δ13C: - 25‰ ± 2.1‰; δ15N: + 8.5‰ ± 1.1‰; C/N: 8.1 ± 1.2). Source recognition of SPOM was based on carbon isotopes because they are conservative and distinct between end-members (effluent detritus and bacterial biomass). Using a mixing model, bacterial biomass in the river was calculated to account for < 20% and < 56% of bulk suspended particulate organic nitrogen in winter and summer, respectively. An N budget showed that bacterial N was a small proportion of total nitrogen (< 7.4%) in the riverwater.