New Zealand's icy visitors - past and present
Scour marks of the seabed were probably made by an iceberg measuring between 2 and 5 km long.
November saw some unusual visitors to New Zealand waters, with several icebergs reaching the South Island’s east coast. NIWA oceanographer Dr Mike Williams estimated that the bergs probably came from the Ronne Ice Shelf on the other side of Antarctica.
Estuary health check
Scientists from NIWA and Canterbury University are developing a diagnostic toolkit to assess the health of the Avon-Heathcote Estuary before and after a new wastewater outfall is installed.
Treated wastewater has been discharged into the estuary for about 40 years. The high levels of nutrients it contains may be responsible for problem blooms of sea lettuce in summer.
Customary Coastal Management Workshop
Karengo harvest at Mahia. (Photo: Sheryl Miller, NIWA)
21–22 June, Te Papa, Wellington.
NIWA’s National Centres for Coasts & Oceans and Fisheries & Aquaculture will host a workshop to highlight how increased scientific knowledge can advance customary management of the coastal environment.
Increasingly, iwi and managers of taiapure and mātaitai (traditional fishing grounds) have regulatory responsibilities for customary management of the coastal environment and kaimoana resources.
A flexible way to model sediment dispersal
Water depth in the Middle Waitemata Harbour, represented on a flexible grid.
NIWA has recently upgraded its modelling software for simulating the dispersal of sediments and contaminants in coastal waters.
The new software represents water depth on a ‘flexible grid’. This allows the user to zoom in on water flow and sediment transport in areas that are complicated or of particular interest, such as valuable habitats or near stormwater discharges.
GeoEel sees beneath the seafloor
Profile of sedimentary basins in the Gulf of California. Scripps Institute of Technology
Ever wished you had Superman’s X-ray vision? Our new digital seismic streamer is the next best thing.
The ‘GeoEel’ streamer is an array of 768 hydrophones towed behind a ship. The hydrophones pick up sound signals reflected off sedimentary layers and geological structures up to 3 km beneath the seabed.
Sophisticated sonar for marine habitat mapping
Map of seafloor habitat types on Wellington’s south coast.
NIWA vessels’ multibeam sonar capabilities offer a rapid, accurate means of mapping marine habitats, with myriad applications.
NIWA recently applied this technology to map 46 square kilometres of seafloor habitats in and around the proposed Taputeranga Marine Reserve on Wellington’s south coast, in conjunction with Victoria University and the Department of Conservation.
Combining the shallow water capabilities of survey launch Pelorus and RV Kaharoa enabled the team
Ocean Survey 20/20 gets underway
An orange roughy swims above a stony coral reef on the Pyre seamount, northern Chatham Rise, at a depth of 1020 m.
RV Tangaroa spearheaded the first of the Government’s Ocean Survey 20/20 (OS 20/20) projects last month with the first of three voyages to the Chatham Rise and Challenger Plateau.
OS 20/20 is a long-term Government strategy to survey and explore New Zealand’s oceans, including those around Antarctica, to better manage and sustainably use their resources.
Little is known about the biodiversity of New Zealand’s offshore seabed
Ashley Estuary in good shape
Ashley Estuary
Environment Canterbury (ECan) commissioned NIWA to survey the central and southern portion of the Ashley Estuary following its designation as an Area of Significant Natural Value.
The survey was to provide baseline information on the estuary’s intertidal sediments and associated biota (plant and animal life), and to compare the current state of the sediments with their condition when last surveyed in 1982.
Results showed that the organic content of the sediments was generally low.
Bounty and Antipodes Islands surveyed
Antipodes
NIWA has recently submitted results of hydrographic surveys of the Bounty and Antipodes Islands to Land Information New Zealand (LINZ).
These rugged, uninhabited islands lie in subantarctic waters 650 to 850 km southeast of New Zealand, forming the southeastern sector of our Exclusive Economic Zone (EEZ).
The seafloor around the islands was mapped from RV Tangaroa last year using high-resolution multibeam echosounding equipment.
Workshop explores coastal
Parliamentary Commissioner for the Environment Dr Morgan Williams (centre) with NIWA’s General Manager Coasts and Freshwater Dr Clive Howard-Williams (left) and Centre Leader for the National Centre for Coasts & Oceans Dr Ian Wright (right).
Nearly 100 participants attended our two-day workshop on ‘Effects of land-based activities on the coastal environment’ in May.
Making the most of a little iron
Deploying the CTD (Conductivity, Temperature, Depth) instrument, which captures water samples at depth.
A NIWA-led study has shed light on the role of iron in controlling plankton productivity, and points to dust as a source of this important element in the New Zealand EEZ.
Iron is essential to life in the oceans, where it’s used by microscopic plants (phytoplankton) living in the surface layer to convert sunlight to energy.
