The large fucoid alga Durvillaea potatorum (southern bull kelp) has been identified as a suitable species for offshore seaweed aquaculture due to its large size, preference for wave-exposed sites, and high levels of bioproducts. However, there is a limited understanding of its reproduction and early life-cycle biology and a lack of scalable nursery techniques. We conducted experiments assessing: 1) gamete release, fertilisatio...

Ocean acidification (OA) driven by increasing atmospheric CO 2 is altering marine biodiversity. However, impacts of OA on ecosystem functioning at the community level, including calcification, primary production and nutrient uptake, remain largely unknown. Here, we conducted community transplant experiments at natural CO 2 vents to assess how declining pH affects marine community species composition, biomass, and key ecosystem...

Seaweed cultivation is gaining interest world-wide for both food and non-food applications. Global seaweed aquaculture production currently exceeds 32 Mt WW per annum but is dominated (86% of total) by Asian countries. To meet future demand for seaweed products, regions beyond Asia with aquaculture production potential are being explored. The goal of this study was to assess the suitability of the native kelp Macrocystis pyrif...

Ongoing ocean global change due to anthropogenic activities is causing multiple chemical and physical seawater properties to change simultaneously, which may affect the physiology of marine phytoplankton. The coccolithophore Emiliania huxleyi is a model species often employed in the study of the marine carbon cycle. The effect of ocean acidification (OA) on coccolithophore calcification has been extensively studied; however, p...

The threat posed by ocean acidification (OA) to the diversity and productivity of New Zealand marine ecosystems is assessed in a synthesis of published trends and impacts. A 20‐year time series in Subantarctic water, and a national coastal monitoring programme, provide insight into pH variability, and context for experimental design, modelling and projections. A review of the potential impact of changes in the carbonate system...

Organisms are projected to face unprecedented rates of change in future ocean conditions due to anthropogenic climate‐change. At present, marine life encounters a wide range of environmental heterogeneity from natural fluctuations to mean climate change. Manipulation studies suggest that biota from more variable marine environments have more phenotypic plasticity to tolerate environmental heterogeneity. Here, we consider curre...

In the Northern Hemisphere, brown seaweeds in the Order Fucales have been used extensively as bio‐monitors of heavy metal contamination in sea water, but in New Zealand there has been no assessment of the suitability of the Fucales in this role. We measured iron (Fe) and zinc (Zn) concentrations in the intertidal fucalean seaweed Hormosira banksii at three sites in Otago, southeastern New Zealand and two sites at Leigh, northe...

A study of water velocities near subtidal kelp fronds, relative to the motion of the kelp itself, is described. The dynamic model developed by Utter and Denny (1996) is used to develop a quantitative measure of the relative velocity vector, u r . The numerical model is extended through the addition of a current, use of a larger drag coefficient, and explicit consideration of u r . The model is tested by comparing it with micro...