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Nutrient limitation of algal biomass in the Waikato River

TR 2018/44

Report: TR 2018/44

Author: Piet Verburg (NIWA)

About this report

This report was commissioned by the Technical Leaders Group for the Healthy Rivers Wai Ora Project Report No. HR/TLG/2015-2016/3.4

This study, commissioned by the Technical Leaders Group (TLG) of the Healthy Rivers/Wai Ora project, aims to improve understanding of the relationships between algal biomass and nutrients in the Waikato River, by an in-depth analysis of the water quality data collected monthly by Waikato Regional Council (WRC) at 10 sites along the river’s length.

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Nutrient limitation of algal biomass in the Waikato River [PDF, 5.5 MB]

 

Contents

1 Introduction
2 Methods and data limitations
3 Results and Discussion
3.1 Relationships between chlorophyll a and TN and TP
3.2 Station comparisons
3.3 Seasonality
3.4 Long-term trends
3.5 Upstream nutrients versus downstream chlorophyll a, and flushing effects on chlorophyll a
3.6 Frequency distributions of potential growth limiting conditions
3.7 Nutrient conditions when chlorophyll a is high
3.8 Nutrient and chlorophyll a concentrations and relationships under different TN:TP conditions
3.9 Proportions of dissolved inorganic nutrients and particulate nutrients
3.10 National Objectives Framework Numeric Attribute States and relationships between chlorophyll a and nutrients in the Waikato River
3.11 Predicting chlorophyll a from TP and TN
4 Acknowledgements
5 References