Table_1_Temporal Stability of Phytoplankton Functional Groups Within Two Agricultural Irrigation Ponds in Maryland, USA.docx

Phytoplankton functional groups and their influence on water quality have been studied in various types of water bodies but have yet to be studied in agricultural irrigation ponds. Freshwater sources (e.g., lakes, rivers, and reservoirs) have been previously shown to exhibit high spatial and temporal variability in phytoplankton populations. Improvements in the monitoring of phytoplankton populations may be achieved if patterns of stable spatial variability can be found in the phytoplankton populations through time. The objective of this work was to determine if temporally stable spatial patterns in phytoplankton communities could be detected in agricultural irrigation ponds using a functional group approach. The study was performed at two working agricultural irrigation ponds located in Maryland, USA over two summer sampling campaigns in 2017 and 2018. Concentrations of four phytoplankton groups, along with sensor-based and fluorometer based water quality parameters were measured. Temporal stability was assessed using mean relative differences between measurements in each location and averaged measurements across ponds on each sampling date. Temporally stable spatial patterns of three phytoplankton functional groups were found for both ponds over the two sampling seasons. Both ponds had locations where specific phytoplankton functional group concentrations were consistently higher or lower than the pond's average concentration for each sampling date. Zones of consistently higher or lower than average concentrations were associated with flow conditions, pond morphology, and human activities. The existence of temporally stable patterns of phytoplankton functional group concentrations can affect the outcome of a water quality assessment and should be considered in water quality monitoring designs.

目前学界已在多种水体中开展浮游植物功能群(Phytoplankton functional groups)及其对水质影响的相关研究，但针对农业灌溉池塘的相关探索仍较为匮乏。已有研究表明，湖泊、河流与水库等淡水水体中的浮游植物种群存在显著的时空异质性。若能通过时序监测识别出浮游植物种群的稳定空间分布模式，或可推动浮游植物种群监测技术的优化升级。本研究旨在采用功能群分析方法，探究美国马里兰州两处实际运行的农业灌溉池塘中，浮游植物群落是否存在具有时间稳定性的空间分布模式。本研究于2017年与2018年夏季开展了两轮采样作业，对两处农业灌溉池塘进行了采样监测。本次研究测定了四类浮游植物功能群的浓度，同时采集了基于传感器与荧光计获取的水质参数数据。研究采用各采样点位的测量值与各采样日全池塘平均测量值的平均相对差值，对浮游植物群落的时间稳定性进行评估。两轮采样季的结果均显示，两处池塘的三类浮游植物功能群均存在具有时间稳定性的空间分布格局：部分采样点位的特定浮游植物功能群浓度，在各采样日均显著高于或低于池塘整体平均浓度。上述浓度显著偏高或偏低的区域，与池塘水流条件、形态特征以及人类活动密切相关。浮游植物功能群浓度的时间稳定分布模式，会对水质评估结果产生显著影响，因此在水质监测方案设计中应予以充分考量。