Heat is destroying Australia’s underwater forests. Seaweed biobanks could help save them

by bpckle | Jun 29, 2026 | In the Media

Australia’s Great Southern Reef is built not by coral but by seaweed. The seaweed forests on these rocky reefs stretch more than 8,000 kilometres around southern Australia.

Amid the swaying fronds live seadragons, rock lobsters, giant cuttlefish and southern blue devils. The reef is home to more than 1,500 seaweed species and contributes billions to the economy each year.

But these remarkable cold water forests face a worsening threat. The ocean is getting steadily warmer, pushing seaweed species outside their survival zone. Much of this damage is done by sudden marine heatwaves, where temperatures spike and remain high for some time. Heatwaves have driven the decline of seaweed forests across the country.

To protect these underwater forests, we need to preserve their genetic diversity. We led the first attempt to cryopreserve (freezing and storing reproductive material at ultra-low temperatures) a key Australian seaweed, crayweed, and found the idea shows promise, though the techniques need to be perfected.

Why does seaweed matter?

Most of us encounter seaweed as a slightly stinky mass spotted when walking along a beach. But underwater, these large algae (not plants) form beautiful forests swaying in the current – some as tall as 30 metres.

Seaweed forests are among the most productive ecosystems on Earth. Like forests on land, they provide habitat, shelter and food for many creatures. They underpin valuable fisheries such as lobster and abalone.

When local populations are wiped out, they take something important with them – genetic diversity. Species with high genetic diversity can better adapt to change. Some populations will be able to tolerate heat better, for instance. But if these populations disappear, their unique genes go with them.

In 2011, an extreme marine heatwave in Western Australia led to two common seaweed species losing an estimated 30 to 65% of their genetic diversity. These losses may mean poorer outcomes in response to intensifying threats.

Consider the crayweed

Golden-brown crayweed (Phyllospora comosa) once formed extensive underwater forests along Sydney’s coastline. Many of these disappeared in the 1980s, likely due to sewage pollution. But crayweed didn’t return even after pollution levels fell.

Over the past 14 years, scientists and divers have replanted this species around Sydney through Operation Crayweed. Their work has led to the return of self-sustaining populations, including Australia’s first named seaweed forest – Yanggaa forest at Coogee Beach.

But restoration may not be enough in a rapidly warming ocean. Our research shows separate crayweed populations harbour unique genetic diversity – and some individuals appear better equipped to tolerate heat. It may make sense to plant germlings (baby seaweed) from these individuals in vulnerable populations to boost their chances of survival.

Of seed banks, biobanks and cryopreservation

For decades, thousands of land-based plant species have had their genetic diversity preserved through seed banks. The seeds stored are sleeping but still alive. If planted in the right conditions, they will grow.

Some kelp species can also be kept alive in biobanks – not as seeds, but in a microscopic form (gametophytes) able to be kept alive in laboratories for years. Current kelp collections support research, aquaculture and restoration programs around the world, including in Australia.

These banks are important. But they won’t be enough. The majority of seaweed species dominating the Great Southern Reef are known as fucoids. Unlike true kelps, fucoids don’t have this microscopic life stage – they release sperm and eggs directly into seawater that fertilise and form germlings. This makes species such as crayweed, bull kelp (Durvillaea potatorum), Cystophora sp. and Scytothalia dorycarpa more challenging to conserve.

It is possible to bank species which rely on sexual reproduction, such as humans, cows, corals and fucoids. Assisted reproduction methods such as IVF rely on cryopreservation: storing reproductive material, tissue or early life stages at ultra-low temperatures (around –196 °C) so it remains viable for future use.

Our recent research tested whether frozen crayweed sperm and germlings were viable after being thawed. We found the sperm did well, but the germlings did not (for now). Our ultimate goal is to develop proven methods able to work across a broader range of Australian seaweed species.

Preserving the genetic diversity of seaweed species would mean these genes can be drawn on to bring them back. This buys valuable time and keeps the door open for new methods such as assisted gene flow, where individuals from better-adapted populations are used to help vulnerable ones cope with warmer conditions.

Time for seaweed biobanks?

Australia already has an impressive algal culture collection and is a global leader in coral cryobanking.

Even so, it will take real work to develop methods of preserving the forest-forming seaweed species that rely on sexual reproduction. We need to learn which populations contain unique or threatened genetic diversity, understand which are most vulnerable to climate change and improve freezing and recovery techniques.

Choosing which species and populations should be done alongside Indigenous custodians, governments, conservation organisations and local communities.

Cryobanking doesn’t solve climate change or replace the need to protect habitat. It’s an insurance policy for biodiversity. Much has already been lost. Preserving the remaining genetic diversity of our seaweed forests may well be critical to the survival of the Great Southern Reef.

Catalina A. Musrri received funding from the Australian Government International Research Training Program scholarship and the University of Sydney, Marine Studies Institute Ruhm Award in Marine Ecology. This work is funded by an Australian Research Council Linkage Grant.

Georgina Wood is supported by the Australian Research Council through an Industry Fellowship and Linkage Grant, and a Revive & Restore Wild Genomes grant.

As communities face more frequent hazard warnings, we need better systems to avoid ‘emergency fatigue’

by bpckle | Jun 29, 2026 | In the Media

Earlier this month, Wellington declared a local state of emergency, including evacuation orders, when forecast powerful swells threatened to inundate coastal properties.

Hundreds of people evacuated, but when the damage and inundation remained limited, mainstream and social media raised questions about whether the hazard warning was an overreaction that risked creating “emergency warning fatigue”.

As extreme weather events are becoming more frequent as a consequence of climate change, communities will be dealing with more hazard warnings. Some of them may turn out to be too cautious.

Researchers are investigating why some people already fail to follow protective orders in emergency warnings.

We argue a “relational governance” approach can address this issue by building trust and shared responsibility between communities, experts and governing bodies before and after events.

This concept provides a platform for effective communication, not just in the lead-up to a hazardous event but also afterwards. This reduces the risk of people taking warnings less seriously even when some turn out to be false alarms.

Forecasts are probabilities, not promises

Science does not provide certainties, but rather probabilities informed by observations, models and prior understanding.

In the case of the Wellington swell, scientists could say with high confidence that waves would be large. Atmospheric conditions drove a sustained and strong southerly airflow extending some 2,000 kilometres from near the Antarctic margin all the way past the eastern coast of the North Island.

Strong winds sustained over a long, uninterrupted distance provided conditions for generating large swells with damaging impacts on shore. Indeed, one wave buoy recorded a maximum wave height of around 10 metres, with peak averages closer to 4 metres. This was without doubt an extreme event.

But local impacts, such as coastal inundation and damage, depend on many additional factors. This includes tide levels, local-scale coastal topography and bathymetry, and subtle variations in storm evolution.

Models capture some of these variables, but not perfectly. Small differences in these factors can lead to large differences in outcomes from one place to the next.

Nevertheless, decision-makers are often forced to act in situations of deep uncertainty in which scenarios may not play out as expected.

Crying wolf

Based on Aesop’s Fable, the “cry wolf” syndrome suggests that repeated false alarms undermine the efficacy of early warning systems.

The syndrome has been studied in psychology, economics, sociology and hazard-management disciplines. Generally, research suggests the likelihood of people responding appropriately to a hazard warning is not diminished by it, as long as the basis for the warning is well understood.

Social connectedness, previous experiences of disasters and institutional trust all play a role in how people respond to alarms.

Narrative escalation

In April 2026, a widespread red warning was issued over the North Island due to the uncertain track and potential severity of ex-tropical cyclone Vaianu.

Some councils in the Hawkes Bay region declared local states of emergency. One local mayor refused to join them, suggesting the country was becoming “woke” when it came to emergency declarations.

This narrative escalation mirrors dynamics that have been observed during other politically contested events such as pandemics, wildfires and floods.

When trust in institutions is contested, precautionary warnings can become entangled with narratives about government competency, bureaucratic overreach and legitimacy. The overall effect is more akin to “institutional trust fatigue” than emergency warning fatigue.

When that happens, hazard warnings become subject to political agendas rather than acting as technical communications. The “woke” frame now exists in New Zealand’s political discourse and could apply to future emergency declarations.

What happens afterwards matters just as much

In New Zealand, emergency declarations are designed primarily as legal and operational tools, rather than risk-communication tools.

Sound precautionary emergency management can appear indistinguishable from overreaction when damage is either successfully avoided or the hazard impact is less than forecast.

One solution is to move from a model focused on issuing warnings to one that offers clear justification and publicly accessible reviews following an event. Such systems already exist elsewhere.

For instance, California’s emergency-management system requires timely, open post-event reports that explore what happened, what decisions were made, the effectiveness of actions, and the lessons learned.

However, such systems often focus on what an agency learned from an event rather than public legitimacy. While public accountability is required, it is an insufficient measure for rebuilding trust.

Relational governance focuses attention on relationship – between communities, experts and agencies – before, during and after extreme events.

Iwi and community groups should be involved, as critical knowledge-holders, in the design of such frameworks, including input into thresholds that trigger actions.

Post-event reporting can then form the basis of iterative and reflective processes of public engagement that build trust, legitimacy and a shared understanding of uncertainty.

As communities encounter climate hazards with increasing frequency, such relational work to strengthen connections between communities and agencies may prove as important as the warning systems themselves.

Shaun Eaves receives funding from Royal Society Te Ap?rangi Marsden Fund.

James Renwick receives funding from MBIE via an Endeavour grant.

Cathrine Dyer does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.