Integrated Catchment Management

Long term in–situ data collection in Tasman Bay

 Research Status: Ongoing
Data buoy

Data buoy

Introduction

The Motueka River plume outwelling region of Tasman Bay has been characterized through a series of synoptic surveys of water column and seabed properties/processes. Such point-in-time investigations, however, do not adequately demonstrate either the evolving effects of short term variation in river flow/composition (e.g. flood events) or the longer term implications of changing weather patterns (e.g abnormal wet or dry periods) on coastal ecosystem processes. Long term data collection is therefore a prerequisite to filling in the gaps in our understanding of the effects of catchment activities on the river plume ecosystem.

A buoy-mounted, in situ, real time data collection facility was therefore deployed in the plume-affected region of western Tasman Bay. The buoy station is located 6 km offshore from the Motueka River mouth and has subsequently been adopted by the Tasman District Council as a State of the Environment (SOE) monitoring site. The station was purposely established at a point 1 km from the outer boundary of an aquaculture management area proposed for long line culture of GreenshellTM mussels.

Research Approach

Hourly midwater measurements of current speed & direction, conductivity, temperature, depth, chlorophyll a and turbidity are telemetered to Cawthron to automatically update data files and graphics. Additional surface and bottom water sensors are included to identify stratification characteristics, and variation in the quality of the feeding environment for scallops is assessed with near-bottom chlorophyll a and turbidity sensors.

Research Results

Over the one-week period, 15-22 March 2007, we observed a 2C decrease in seawater temperature (18.5-16.5 C). This temperature decline seemed to signal the onset of a brief autumnal phytoplankton bloom with a series of chlorophyll a peaks of up to ~7 mg/m3.

A short sharp rainfall event was captured 23-24 May that resulted in a slight decrease in midwater temperatures and salinities along with a distinct peak in turbidity. It took about 12 hours for the suspended sediment plume to reach the buoy.

More details »

Map of buoy location Autumn algal bloom March 2007

Map of buoy location

Autumn algal bloom March 2007

Recent Publications

Year Title File Size
2012 A Summary of Outcomes and selected formal publications from the Integrated Catchment Management (ICM)research programme:2000 – 2011
pdf       1.08MB
2011 Integrated Catchment Management – Special Issue of the NZ Journal of Marine & Freshwater Research  
2010 Spatial Delienation of the Motueka River Plume Influence in Tasman Bay based on Seabed Characteristics pdf       2.33MB
2007 Nutrient Loading from the Motueka River into Tasman Bay, 2005 and 2006. pdf       873KB
More publications on this topic »
All ICM Publications »

BMPs, BEPs and Guidelines

Title Description
Tonga Island Marine Reserve: Proposed protocol for ongoing subtidal biological monitoring This document presents a proposed protocol for ongoing monitoring of the Tonga Island Marine Reserve...More »  
All BMPs, BEPs & Guidelines »

Primary Contacts:


Image - Reid Forrest Reid Forrest  EmailSend email to reid.forrest
Phone: 035482319
Institute
Cawthron Institute
Expertise
Sediment geochemistry
Image - Paul Gillespie Paul Gillespie  EmailSend email to paul
Phone: 03 548 2319
Fax: 03 546 9464
Institute
Cawthron Institute
Expertise
Estuarine & marine microbial ecology
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Page last updated Tuesday, 20 November 2007

Related areas

Ecosystem models of Tasman & Golden Bays Fine sediment: bringing the geomorphology and biology together River monitoring River plume ecosystem Sediment generation, delivery and impacts Sediment learning group Stakeholder issues Tasman Bay productivity