Freshwater Update 78, September 2018

The diatom (Lindavia intermedia) that causes lake snow—nuisance slime in clean-water lakes that ruins angling and can block water intakes—was apparently introduced to New Zealand shortly before 2002, but was widespread by 2005.

A seminal review has just been completed. It describes aquatic life within aquifers, outlines the ecosystem services and values supported by groundwater ecosystems, and discusses the key factors that affect and threaten groundwater ecosystems.

A technical guide to the Periphyton Attribute Note under the National Policy Statement for Freshwater Management (NPS-FM) 2014 (as amended 2017) has been released, as a draft, this month by the Ministry for the Environment.

Many of the riverine and peat lakes in the Lower Waikato are degraded, with turbid water and algal blooms predominating. Recent research has focused on assessing the potential use of geo-engineering products, to clear the water column and cap lake sediments, to minimise the release of the nutrient phosphorus that can fuel algal blooms.

Swimming is a popular activity in Aotearoa-New Zealand. Two attributes of waters that strongly affect aesthetic quality and safety for swimming are visual clarity and faecal contamination. It turns out that these two attributes are fairly well-correlated (inversely) in New Zealand rivers, such that (easily seen) visual clarity provides a rough-but-useful guide to (unseen) microbial quality.

NIWA is working with DairyNZ, Regional Councils and farmers on a new project to evaluate riparian planting options that have economic as well as environmental benefits. The project is co-funded by the Sustainable Farming Fund. Read the article Research into productive riparian buffers on the DairyNZ website,  or contact Dr Fleur Matheson.