Waterways Centre for Freshwater Management, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
Cawthron Institute, Private Bag 2, Nelson, New Zealand; Environmental Research Institute, University of Waikato, Private Bag 3105, Hamilton, New Zealand.
Sci Total Environ. 2018 Jan 15;612:71-80. doi: 10.1016/j.scitotenv.2017.08.085. Epub 2017 Sep 1.
Toxic benthic cyanobacterial proliferations, particularly of the genus Phormidium, are a major concern in many countries due to their increasing extent and severity. The aim of this study was to improve the current understanding of the dominant physicochemical variables associated with high Phormidium cover and toxin concentrations. Phormidium cover and anatoxin concentrations were assessed weekly for 30weeks in eight predominately cobble-bed rivers in the South Island of New Zealand. Phormidium cover was highly variable both spatially (among and within sites) and temporally. Generalized additive mixed models (GAMMs) identified site, month of the year, conductivity and nutrient concentrations over the accrual period as significant variables associated with Phormidium cover. Cover was greatest under low to intermediate accrual dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP) concentrations. Accrual nutrients had a strong, negative effect on cover at concentrations>0.2mgL DIN and 0.014mgL DRP. The effect of flow was generally consistent across rivers, with cover accruing with time since the last flushing flow. Total anatoxins were detected at all eight study sites, at concentrations ranging from 0.008 to 662.5mgkg dried weight. GAMMs predicted higher total anatoxin concentrations between November and February and during periods of accrual DRP<0.02mgL. This study suggests that multiple physicochemical variables may influence Phormidium proliferations and also evidenced large site-to-site variability. This result highlights a challenge from a management perspective, as it suggests that mitigation options are likely to be site-specific.
有毒底栖蓝藻的增殖，尤其是束丝藻属（Phormidium）的增殖，是许多国家的主要关注点，因为它们的范围和严重程度都在增加。本研究旨在提高对与高束丝藻覆盖率和毒素浓度相关的主要理化变量的现有认识。在新西兰南岛的 8 条主要卵石河床河流中，每周评估一次束丝藻覆盖率和鱼腥草毒素浓度，共 30 周。束丝藻的覆盖率在空间（在站点之间和站点内部）和时间上都有很大的变化。广义加性混合模型（GAMM）确定了站点、一年中的月份、电导率以及在累积期的营养物浓度是与束丝藻覆盖率相关的重要变量。在低至中等累积溶解无机氮（DIN）和溶解反应性磷（DRP）浓度下，覆盖率最高。在浓度>0.2mgL DIN 和 0.014mgL DRP 时，累积养分对覆盖率有很强的负作用。河流之间的水流效应基本一致，随着上次冲洗水流以来的时间推移，覆盖率不断增加。在所有 8 个研究点都检测到总鱼腥草毒素，浓度范围从 0.008 到 662.5mgkg 干重。GAMM 预测 11 月至 2 月和 DRP 累积期间（<0.02mgL）总鱼腥草毒素浓度更高。本研究表明，多个理化变量可能会影响束丝藻的增殖，并且还证明了站点之间存在很大的变异性。这一结果从管理角度提出了一个挑战，因为这表明缓解措施可能是特定于站点的。
