Cross-shelf Exchange (C-SEX) database

The C-Sex programme aims to determine the processes driving variability in shelf circulation, nutrient supply, and productivity on the northeastern NZ shelf and coastal zone. The 14th voyage (Dec 2002) is a pilot study upon which a series of 'seasonal' voyages over the next year will be based. These voyages will be designed to determine the impact of sediment biogeochemistry and nutrient fluxes on pelagic production in the Firth of Thames. Objectives will include: - Characterise the spatial distribution of sediment organic matter in the Firth of Thames. - Map spatial gradients in water column properties throughout the Firth of Thames. - Continue moored time-series of physical properties at two contrasting sites: outer shelf and coastal. - Augment time-series of hydrographic data along a cross-shelf transect from shallow to deep water off Cape Brett. Purpose: To determe how open-ocean processes affect coastal ecosystems, in particular, look at how processes such as upwelling, mixing, internal waves and stratification affect the nutrient supply and ecosystem productivity of coastal and shelf environments.

Measurements for: fluorescence, current, temperature, salinity, conductivity, pressure, dissolved oxygen, turbidity, trace gases, chlorophyll a, nutrients, HPLC pigment, plankton, sediment, 12-hr primary production

Tutukaka shelf edge, Firth of Thames

since 1996 (including north-western side of Coromandel Peninsula), however the seasonal collection of Firth of Thames water column properties started in Dec 2002.

Biofish/ADCP transects, core sampling, CTD and water sampling casts, acoustic current meter, MicroCAT and temperature loggers. Permanent moorings at the Poor Knights and entrance to Firth of Thames. Frequency of collection: repeated 'seasonally' – usually March, July, September, December.

Mooring sampling failure. Gaps in collection: The Firth of Thames is not sampled during the early stages of the project (1996-97). Samples lost from the project due to varying reasons are documented in the voyage reports. Data quality: Not reported Attribute accuracy: Biological variables, particularly chlorophyll, difficult to measure from moorings due to fouling. Reliable biological measurements were taken during vessel sampling. Completeness: Not reported

voyage reports, graphs, maps Digital Format: MS Access, MS Word

Sediment – pelagic interactions Aquaculture - Assessment of suitable AMA, effects of current marine farms. General resource management Fisheries

See NIWA Sensitivity/Confidentiality: See NIWA

Further survey voyages planned until 2005.