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Abstract: Otago Harbour is a long (23km), narrow (mean width=2km), shallow (mean water depth=4.5m) tidal inlet covering 46km2 on the southeast coast of South Island, New Zealand (45°50′S, 170°35′E). Development of the City of Dunedin (pop. 125,000) and its associated port at Port Chalmers has been associated with extensive dredging, land reclamation, and shoreline construction. Here we develop a carbonate sediment budget for Otago Harbour, with limits defined at Mean High Water Spring and the harbour entrance; from the water–air interface to a few cm below the sediment–water interface. Carbonate is added to this system primarily by in-situ production (∼10,000tonnesCaCO3 y−1) and by transport though the harbour entrance from the longshore system (∼24,000tonnesCaCO3 y−1). Shellfishing (∼2tonnesCaCO3 y−1), dredging (∼18,000tonnesCaCO3 y−1), and early sea-floor processes such as abrasion and dissolution (∼2000tonnesCaCO3 y−1) remove carbonate from the system. The present-day carbonate budget results in ∼14,000tonnesCaCO3 y−1 sediment storage, equivalent to ∼0.14mmy−1 accumulation. Two thousand years ago, the budget would have had nearly the same inputs but many fewer outputs, potentially resulting in storage twice what it is today; projected increases in human impacts suggest that carbonate storage may end within 100 years. Carbonate storage in sediments has a role in preserving environmental information and sequestering carbon, but the major value of a budget model is in clarifying the importance of human impacts. Urban harbours are not in a ‘natural’ state, and increasing human activity, both locally and globally, affects their overall health. [ABSTRACT FROM AUTHOR]

The idea of urban fringe belts has been recognised as a powerful means of understanding the physical form of urban areas and the process of urban outward growth and internal change. Surrounding Auckland's city core, an inner fringe belt can be recognised. Farther out there are middle and outer fringe belts. Fluctuations in socio-economic development, the adoption of new transport modes, land reclamation and topography are major factors influencing the formation of these fringe belts. The examination of changes to fringe belts highlights important issues of urban transformation, which are pertinent to planning and design policies for urban landscape management. [ABSTRACT FROM AUTHOR]

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Denitrification is considered to be an important N removal process is land-based wastewater treatment systems, although in situ denitrification rates have rarely been reported. We investigated the contribution of denitritication to N removal in a land treatment systemby measuring in situ denitrification rates for 12 mo in a Monterey pine (Pines radiata D. Don) sorest irrigated with tertiary-treated wastewater. The variability of denitrification rates was investigated using a nested field design that divides the land treatment system intofour spatial components (irrigation block, topographic position, field site, and sample plot) and two temporal components (sample period,sample day). Denitrification was measured using undisturbed soil cores collected daily, for six consecutive days on 21 occasions throughout the year. Soil moisture content, N03 concentration, available C, denitrifying enzyme activity, and temperature also were measured. The annual denitrification rate in the irrigated soil was 2.4 kg N ha-1 yr-1, and only slightly higher than the unirrigated soil (1.7 kg N ha-1 yr-1). Temporal effects (i.e., seasonal and day-to-day variation) contributedmore than spatial effects to the overall variation in denitrification rates. Multiple regression analysis showed that soil factors could only explain 29 % of the variation in denitrification rates. Soil water-filled porosity was low in the land treatment system, and less than the critical threshold value (74% water-filled porosity) determinedin a laboratory study. We concluded that denitrification in this land treatment system studied was limited by excessive aeration in the free-draining sons. [ABSTRACT FROM AUTHOR]