NZ Freshwater Nutrient and Biomass Measurements for Periphyton 2012 - 2020
Ministry for the Environment and Statistics New Zealand
Periphyton is the slime that coats submerged surfaces in aquatic environments. It is composed of a complex assemblage of organisms that consisting of algae, fungi, heterotrophic microbes and other microorganisms (Biggs, 2000). While periphyton is a normal part of healthy aquatic ecosystems, excess biomass can cause detrimental effects on these ecosystems by smothering habitat, decreasing the oxygen in the water (via decomposition) and degrading the aesthetic quality of the water - affecting the ability to fish, swim or carry out other activities. Periphyton biomass is controlled by a variety of factors such as temperature, shading and nutrients. As part of the National Policy Statement for Freshwater Management (NPS-FM) 2020 periphyton biomass must be managed in NZ waterways including via limiting nutrient concentrations in waterways (NPS-FM 2020, Clause 3.13)
This file contains data from direct periphyton biomass measurements from most regional councils across New Zealand over a period of 8 years (2012 to 2020). This dataset was aggregated for the purpose of creating lookup tables of nutrient concentrations that align with specific periphyton biomass outcomes of the NPS-FM 2020 (a link to the report can be found below). The table contains periphyton biomass measures (expressed in terms of Chlorophyll-a) alongside other possible explanatory variables such as nutrient concentrations (in parts per billion), turbidity, electrical conductivity, temperature, etc. The analysis did not include data from Auckland Council (timeseries were too short), West Coast Regional Council (insufficient data), Tasman District Council, Waikato Regional Council and Gisborne District Council (no suitable data).
In total 11 regional councils contributed roughly 20765 datapoints (the rows) containing 19 variables (columns). These variables are: - Site (the number of the data point itself) - RC (Regional Council that collected the measurement) - RCSiteID (the identifier used by that specific council) - SiteName (the Site where the measurement was collected) - DateChla (date the chlorophyll-a measurement was collected) - Year (Year of collection) - Month (Month of collection) - Chla ( mg chlorophyll-a per square meter) - NOxppb (Nitrous oxide parts per billion) - NH4ppb (Ammonia parts per billion) - DRPppb (Dissolved Reactive Phosphorus parts per billion) - TNppb (Total Nitrogen parts per billion) - TPppb (Total Phosphorus parts per billion) - DINppb (Dissolved Inorganic Nitrogen parts per billion) - EC (Electrical Conductivity) - pH (acidity/basicness of the water at the sample location) - Temp (water temperature in degrees Celsius at time of measurement) - Turbidity (turbidity of the water at time of measurement) - Clarity_m (water clarity, in metres, at the time of measurement)
N/A values in the data set refer to an absence of measurement for that specific variable.
For more information see:
Snelder T, Kilroy C, Booker D (2021) Derivation of Nutrient Criteria for Periphyton Biomass Objectives. Using regional council monitoring data. LWP and NIWA Ltd, Christchurch, New Zealand available at https://environment.govt.nz/publications/derivation-of-nutrient-criteria-for-periphyton-biomass-objectives/
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National Institute of Water and Atmospheric Research; all regional councils
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