New Zealand’s sea temperatures are also hitting record highs. Between 2022 and 2023, oceanic and coastal waters reached their warmest annual temperatures since measurements began in 1982, according to Stats NZ data.
This warming is already threatening coral reefs – the Great Barrier Reef is the hottest it’s been in 400 years – and marine life. But it is also reshaping ecosystems at the very basis of ocean food webs.
Microscopic algae, or phytoplankton, are ubiquitous in the surface layers of the ocean. They represent the foundation of the marine food web and serve as a substantial carbon sink.
Unless we act to cut emissions, these shifts in microalgal composition are projected to get worse as ocean temperatures continue to rise, globally and regionally in the waters off Aotearoa New Zealand.
We are already seeing changes in New Zealand’s microalgal communities.
The abundance and activity of microalgae is usually measured by tracking Chlorophyll A, the pigment most plants use for photosynthesis. Recent reports by Stats NZ show shifts in microalgal biomass, with increases in some regions and declining levels in others.
This graph shows changes in phytoplankton biomass along New Zealand’s coast from 2003 to 2022.Author provided, CC BY-SA
Abrupt shifts in microalgal communities can drive ecosystems into altered states, affecting food webs and fisheries. Such a “regime shift” happened in the North Pacific in 1977 and 1989, with far-reaching consequences for the the entire ecosystem and salmon and halibut fisheries.
More recently in New Zealand waters, lower microalgal biomass and a collapsing food web have been implicated in the cause of “milky flesh syndrome” in snapper from the Hauraki Gulf.
Harmful algal blooms
Harmful algal blooms also appear to be on the rise in New Zealand. The toxins these microalgae produce accumulate in shellfish, and their consumption can be poisonous for people and animals and threaten the economic stability of fisheries.
According to data gathered by the Ministry of Primary Industries, the rise in harmful algal blooms in New Zealand during 2023/24 resulted in the highest number of shellfish harvest closures from biotoxins this decade.
Rising ocean temperatures can accelerate the growth of microalgae that cause toxic blooms, while reducing the nutritional quality and size of microalgae species other marine organisms depend on for food.
As our research shows, microalgal toxins affect the reproduction and early life stages of shellfish species indigenous to New Zealand. New Zealand’s fisheries and aquaculture sectors, collectively worth nearly NZ$4 billion, already face harvest closures, stock losses and reduced recruitment of larvae.
Climate change affects the physiology of microalgae, which in turn has impacts on other marine organisms.Eden Cartwright, Bird Circus, CC BY-SA
Toxic microalgal blooms can also kill marine mammals or make them less resilient to other stress factors, such as higher temperatures.
Addressing the challenge
Understanding how microalgal communities might change under different climate scenarios is a crucial first step.
This knowledge will help us forecast and investigate the downstream effects on the marine environment and develop effective management strategies to safeguard ocean ecosystems and public health.
Knowing when and where harmful algal blooms are likely to occur will lessen the risk for industry and enable effective restoration efforts. Improving our knowledge of the impacts of microalgal toxins on human health will enable safe recreational water use and give clarity on appropriate responses to algal blooms.
Filling these knowledge gaps is urgent. Changes in microalgal communities are already evident and will likely continue at an accelerating pace, with possibly irreversible knock-on effects on ecosystems and ocean-based industries.
Anne Rolton Vignier receives funding from the New Zealand Ministry of Business, Innovation and Employment.
Kirsty Smith receives funding from the New Zealand Ministry of Business, Innovation and Employment.
The gas industry has been unleashing a firehose of rhetoric over concerns Australia could suffer a shortage of gas.
In a series of articles in the Australian newspaper under the banner “Gas Crisis”, industry figures and the Coalition’s energy spokesperson, Ted O’Brien, claim a shortage is going to “destroy” the economy, cause a “crippling energy crisis” and have Australians suffering the ignominy of “cold showers”.
The Medlow Dam in the Blue Mountains has been disconnected by WaterNSW as a “precautionary measure” as investigations continue into the presence of PFAS, known as “forever chemicals”, in the water.
As the WA government looks to expand quarantine boundaries to help stop the spread of the shot-hole borer, a WA arborist who is part of the fight says the pest keeps him awake at night.
Across Australia and around the world, citizen scientists are protecting species by recording sightings, surveying landscapes and collecting samples. No job is too big or too small. As wildlife ecologists, we are indebted to this army of volunteers.
Citizen scientists are everyday people, who are not necessarily experts but who conduct scientific research. There are more than 100,000 citizen scientists in Australia alone. As a nation, we’re the third-biggest contributor to the global citizen science platform iNaturalist. This is staggering considering our relatively small population.
We wanted to find out how citizen science data contributes to decisions by governments and conservation organisations about which species are at risk of extinction, and how they can be conserved.
One of the main ways to help conserve biodiversity is through species extinction risk assessments. These allow scientists and decision-makers to determine how threatened a species is and the best ways to protect it.
Because citizen scientists collect so much data on biodiversity, this information could dramatically improve our ability to accurately assess species. But how useful is citizen science data in achieving this goal? Our new research set out to answer this question.
While we found room for improvement, it’s important to recognise and celebrate the immense value of citizen science data. We would be lost without it.
Citizen science projects can connect communities to biodiversity research and create passionate environmental advocates.Benjamin Fleming
5 types of citizen science data
Our first step was to summarise what types of data citizen scientists are collecting. We found five key types:
evidence that a species occurs at a specific location (usually an image or sound recording including the date and time)
evidence that a species has not been recorded at a specific location
answers to a set of questions about a species and its environment
physical samples such as scat (poo), soil or water samples
collected stories or oral histories, including the voices of First Nations people.
We then considered each data type in terms of its use in addressing the globally accepted criteria for assessing extinction risk. The criteria are set by the International Union for the Conservation of Nature (IUCN), an international organisation devoted to nature conservation and the sustainable use of natural resources.
Searching for fungi with coauthor Jasmin Packer in the Adelaide Hills.University of Adelaide/Nelson Da Silva
Room to improve
We found the data citizen scientists typically collect were often not what was most needed to assess extinction risk under IUCN criteria.
Meeting the criteria requires more than just a record of a species occurring at a given location. Detailed information such as geographic range, and evidence of population decline, is also required.
So simply encouraging citizen scientists to record more ad hoc observations of species is not the best way to inform threatened species listing. Unfortunately, this means the assessment process can’t always benefit from the great work being done.
People charged with assessing a species’ conservation status could make better use of citizen science data. While this wasn’t an explicit finding of the research, the IUCN recognises this. Its recent white paper examines how Indigenous and local knowledge could be better harnessed.
There are ways to ensure citizen science data is better used to inform IUCN assessments. They can include:
planning projects from the outset to ensure the required data is captured
asking citizen scientists to complete structured ecological surveys or collect specific samples
integrating citizen scientist data with that collected by professional scientists.
But our research also revealed good news! We found new methods of data analysis – such as extracting population numbers – are helping scientists use citizen science more effectively.
Australian success stories: Fungimap and FrogID
Some citizen science projects in Australia are feeding into threatened species assessments. We described two of them in our research.
Getting a closer look at a colourful Cortinarius sinapicolor mushroom for Fungimap.University of Adelaide/Nelson Da Silva
In Fungimap, scientists have added extra information to the data collection fields – such as habitat and what the fungus is growing in (animal, soil or wood) – to make records more useful for assessing whether a species is threatened.
New England tree frog (Litoria subglandulosa)Jodi Rowley/Australian Museum
The second is FrogID, led by coauthor Jodi Rowley. It’s a free smartphone app that enables people to record frog calls. Frog experts then identify which species is making the call. More than one million frog records have been collected this way in about six years.
FrogID data helped scientists understand frog persistence after the catastrophic 2019–20 bushfires in southeast Australia. Several species, including the sphagnum frog, have now been listed as threatened using FrogID data alongside professional data.
In both projects, scientists review the images and sound recordings. This ensures their accuracy and means the data is more likely to be included in government databases. Professional scientists also tell citizen scientists what they need to help provide the knowledge needed to assess a species’ extinction risk.
Here’s how to get involved
Citizen science observations are now the largest source of open-source biodiversity data in Australia. It’s important to ensure the data we’re collecting keeps growing.
There are many ways to get involved. The Australian Citizen Science Association website hosts a helpful project finder. You can search for projects in your local area, on a particular subject or theme, or focus on projects suitable for children or beginners.
Erin Roger is the former Chair of the Australian Citizen Science Association and is currently employed by the Atlas of Living Australia, at CSIRO.
Jasmin G Packer is Vice President of Fungimap Inc., a not-for-profit citizen science organisation for Australia's native fungi, and a Research Fellow in the Environment Institute, University of Adelaide. Jasmin receives funding from state and local government, and not-for-profit environmental organisations, for conservation research with citizen scientists and local communities.
Jodi Rowley is the Lead Scientist of the Australian Museum's citizen science project, FrogID. She has received funding from state, federal and philanthropic agencies.
Rachael Gallagher receives funding from the Australian Research Council and the Commonwealth Department of Climate Change, Environment, Energy and Water.
Thomas Mesaglio is currently employed by the Atlas of Living Australia, at CSIRO.
