Soil erosion during heavy rainfall has resulted in the deposition of a thick layer of mud on an intertidal flat in this estuary, smothering much of the shellfish bed shown, and killing the shellfish. This is one example of how human activities in the surrounding catchment can impact on a fragile estuarine ecosystem. NIWA is developing and applying a range of modelling techniques to help understand and predict effects such as this. Examples are given in the news forum, Alien predator: freshwater jellyfish in New Zealand and Assessing human impacts on estuaries: it’s a risky business in this issue.
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Ian Boothroyd
Kay Etheredge
John Green
Jellyfish are familiar marine animals, but they are also found in freshwater. One species is quite common in New Zealand.
Many people will have seen jellyfish washed up on the beaches around the New Zealand coastline following storms at sea. Some will be aware of the notorious “stingers” (box jellyfish – Chironex sp.) that make Northern Queensland beaches potentially lethal for swimming during December and January.
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Kevin Collier
Steph Parkyn
John Quinn
Mike Scarsbrook
For invertebrates intent on recolonising a stream after a disturbance or during stream restoration, simply getting to the stream site is only half the battle.
How far may a mayfly fly? Answers to this sort of question are important for understanding how long it takes a stream to recover from major disturbances, and for predicting whether sensitive stream insects will recolonise restored areas of stream.
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John Austin
Greg Bodeker
Hamish Struthers
Climate change is one problem, ozone depletion is another. True? Maybe not. New modelling techniques are helping to unravel the links between these two environmental issues, and to assess the implications of changes.
Perhaps the two most debated environmental issues in recent years have been climate change and ozone depletion. In the past these have usually been treated as two different and unconnected phenomena. However, recent research has revealed a range of processes that link them.
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Alastair Senior
Malcolm Green
A team of modellers at NIWA Hamilton has developed a way to help environmental managers assess "risk" in sediment-impacted estuaries.
Estuaries are often muddy – ask any Helice crassa (mud crab). The reason is that clay, mud and silt are continuously being eroded from the land and then delivered to the estuary by streams and rivers. Most sediment arrives during and after heavy rainfall.
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Pip Nicholls
When one marine animal has a large influence on other parts of its ecosystem, we call it a key species. These animals can be very useful in monitoring programmes.
One of the goals of marine ecology is to detect and assess the scale of human effects – such as scallop dredging, heavy metal contamination or increasing turbidity – on marine ecosystems.
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Jody Richardson
Bankside and overhanging vegetation not only provides shelter for fish; it also helps a stream to form diverse habitat.
Inanga are one of five galaxiid species that make up the whitebait catch, and in most rivers and streams they form the bulk of the catch. After they have migrated from the sea in spring, inanga spend about six months growing to maturity in fresh water.
On this page
Chief Executive succession
NIWA’s National Centres
NIWA scientist to take up international role
Coastal & Storm Hazards workshop
Sea levels on New Zealand’s eastern flank monitored
Self-cleaning air: prize-winning research
Filthy fumes killing us?
SKINDEEP visits New Zealand
Marine biodiversity – capacity-building in communities
Granular surfaces: structure, organisation, memory
Mapping team discovers underwater volcanoes north of New Zealand
NIWA joins with DHI Water and Environment group
Chief Executive succession
NIWA’s Chief Executive, Paul
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Alastair Suren
Eric Graynoth
Barry Biggs
Shelley McMurtrie
Rachel Barker
Stream restoration in Christchurch is turning drains into living streams.
Have you ever thought what happens when it rains in a city? Rainwater and oily road grime mix into a greasy cocktail, causing traffic accidents on slippery roads. Water and debris quickly flow off impervious roads, carparks and roofs. Stormwater drains can become blocked, causing localised flooding. Stormwater is often conveyed to small streams, which run dirty as the water races to the sea.
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Ben Liley
The products of burning in the tropics can be detected in the atmosphere as far away as New Zealand.
When bush fires rage across parts of Australia, as they did from Boxing Day 2001, they produce spectacular sunsets, and sometimes a haze visible by day as the plume crosses the Tasman Sea.
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Murray Smith
Richard Gorman
Craig Stevens
John McGregor
Waves generated in shallow, enclosed estuaries can have a big impact on marine life. Computer modelling of these wave systems is helping us to predict their effects.
A familiar sight along New Zealand’s coast is waves growing, steepening and breaking as they approach the shore. Even to the most casual observer it is clear these waves must have major impacts on any aquatic plants tough enough to grow beneath them.
