Dynamic Seas

Fisherman onboard a boat overseeing a fishing trawl in the ocean

Using biophysical science to investigate how ecosystems work, are connected and how they respond to change; and providing an evidence-base for effective ecosystem based management (EBM)

Programme leader: Conrad Pilditch, University of Waikato

Our biophysical science underpins the EBM knowledge and tools that Sustainable Seas is developing. Our main themes are ecosystem ‘connectivity’ and ‘tipping points’.

‘Connectivity’ has many aspects but essentially involves how organisms and materials in a marine ecosystem are interlinked. Our research extends from coastal waters to deep offshore canyons, where land-derived material may support bottom-dwelling communities and high productivity on the seabed.

‘Tipping points’, where ecosystems go into rapid decline, are things to be avoided, but not enough is known about the exact conditions and interactions involved to be certain we can prevent them from happening. We are investigating ‘stressing’ factors that are likely to contribute to tipping points in estuary and nearshore rocky reef systems to determine their critical thresholds. These ecosystems can be greatly affected by a wide range of marine and land-derived stressors, such as excessive nutrient and sediment runoff.

Species diversity is a key feature of coastal communities that underpins many ecological functions, but is difficult and time-consuming to gauge over large areas. We are using recently developed genetic barcoding techniques to develop tools that can identify species from environmental DNA found in water samples. This is hoped to be a much more practical and cost-effective than directly sampling each species one-by-one.

Projects

Ecosystem connectivity: tracking biochemical fluxes to inform ecosystem based management

Forensic food webs

We are tracing the fate of water and sediments from land through coastal food webs, evaluating connections between coastal and deep sea habitats, and identifying the effects of key coastal developments (for example, aquaculture) on food web connectivity.  

Tipping points in ecosystem structure, function and services

What causes tipping points?

Tipping points are a rapid transformation that happens when an ecosystem loses its capacity to cope with change. To understand how they manifest in New Zealand waters, we are doing the first national marine experiment in estuaries, harbours and rocky reefs, to identify tipping points, risks and how systems respond to change.  

Stressor footprints and dynamics

Investigating the 'footprint' of materials that flow into the oceans

We are defining the footprint of materials that stress marine ecosystems, such as contaminants, nutrients and sediment. We are using the latest in marine observational technology to collect data – including drifters and ocean gliders – and building better mathematical models to understand water flows within the region.

Submarine canyons: how important are they for connecting coastal and deep-sea ecosystems? (innovation fund)

Comparing submarine canyons’ productivity and role in transport of organic materials

New Zealand’s deep submarine canyons vary in shape, physical characteristics and ecological productivity. To investigate what is behind this difference in productivity, we are using forensic chemistry to track the chemical ‘signatures’ of land- and coastal-derived plant material in the canyon’s sediment and food webs.

Sediment tolerance and mortality thresholds of offshore benthos (innovation fund)

Effects of sediment on seabed species

We are investigating the effects that suspended sediment from human activities, such as mining and fishing, have on the health and survival of important deep-sea species in the South Taranaki Bight. These innovative laboratory experiments will help us understand how resilient species are, and how quickly they can recover.

Quantifying marine biodiversity using environmental DNA (innovation fund)

Measuring biodiversity using eDNA

We are developing an innovative, high-throughput and cost-efficient way to quantify marine biodiversity using environmental DNA extracted from marine water samples. In our initial study, we identified the presence of around 60 species in the test areas, and could clearly distinguish species from neighbouring but distinct habitats.

Estimating historic effects from sedimentation and fishing, Nelson Bays (innovation fund)

Investigating the historical collapses of Nelson Bays' fisheries

Nelson Bays used to support productive green-lipped mussel, oyster and scallop fisheries, which have each collapsed within the last 10–50 years. A review into their decline highlighted sedimentation and bottom contact fishing as potential factors. This project will quantify the fishery losses attributed to historic and contemporary sediment from land, and identify the land-uses the sediment derived from. It will also investigate the additive effects of bottom contact fishing.

Overnight tipping points from a cataclysmic event: impacts, recovery and constraints on rocky reef ecosystems (innovation fund)

Investigating the recovery of Kaikoura's coastal kelp forests

The uplift of Kaikōura’s coastline due to the November 2016 earthquakes caused an unprecedented loss of kelp forests, which provide habitat and energy for other species. This has significant implications for nutrient cycling, primary productivity and overall functioning of nearshore ecosystems. This project is investigating the long-term resilience of kelp thrust into shallow water in the subtidal zone, and the potential mechanisms affecting canopy expansion, colonisation and survival. This will help determine which kelp beds are likely to recover, the environmental conditions likely to promote recovery, and which beds are vulnerable to further decline.

Latest news and updates

Award recognises contribution to marine science

University of Waikato scientist Professor Conrad Pilditch is the 2018 winner of the New Zealand Marine Sciences Society Award. The Award recognises his continued and outstanding contribution to marine science in New Zealand.

Consultation opens re 2019–2024 strategy

Improving marine management is critical to New Zealand's future health and wealth, but research in isolation is not enough. Excellent engagement with, and participation from, all users and sectors of society is essential.

We therefore invite comment on our draft strategy for Phase II (2019–2024). This strategy has been co-developed with Māori and stakeholders.

Sun, sea, sand – and marine science

During Seaweek, more than 4,600 school pupils joined 6 Sustainable Seas researchers for 3 days of marine science fieldwork in Tasman Bay, as part of the LEARNZ virtual field trip Sustainable seas – essential for New Zealand’s health and wealth.