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Nutrient limitation of algal biomass in the Waikato River

TR 2018/44
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Report: TR 2018/44

Author: Piet Verburg (National Institute of Water & Atmospheric Research Ltd (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.

Read or download the report

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