Category: Science

Source: NIWA – National Institute of Water and Atmospheric Research

Strange fish behaviour has been captured by NIWA scientists working in New Zealand’s Marlborough Sounds.

They were looking at the abundance and anatomy of blue cod (Parapercis colias), research that involved using lasers attached to underwater cameras to measure fish size and number.

NIWA marine ecology technician Charlotte Bodie noticed something unusual when analysing the video footage. 

“When trying to count and measure the blue cod, we saw that they were chasing our lasers, just like cats do! I have trudged through a lot of underwater footage in my time, but never seen something like this. No other species seemed to be doing it.

“It certainly broke up the monotony of the work. We do a lot of video analysis and see plenty of interesting and unique fish behaviours, but unfortunately don’t have time to investigate everything,” said Charlotte.

Fellow NIWA marine ecology technician Brooke Madden said that while it was a nuisance at first, the behaviour was quite useful.  

“It made it hard for us to count blue cod as they tended to aggregate and follow the lasers. But it also meant we could measure the fish more accurately because they swam closer to the lasers,” says Brooke.

Unfortunately, because the research in question wasn’t about fish behaviour, the team have yet to decode why the cod were acting in this way.

“They are very inquisitive fish with large lateral eyes that can rotate independently, allowing them to see almost anywhere around them. Finding out why they chase the lasers like cats could make a great project one day,” said Charlotte.

The New Zealand blue cod is a temperate marine fish that prefers shallow waters and rocky coasts. Adults can grow up to 60cm in length and weigh up to 3kg. 

They are protogynous hermaphrodites, meaning they can change sex from female to male, and are an important recreational and commercially harvested species for New Zealand.

The project is funded by Fisheries New Zealand and focuses on identifying and understanding the juvenile habitats of blue cod.It uses data from MBIE-funded research, mapping juvenile fish habitat bottlenecks.

Source: NIWA – National Institute of Water and Atmospheric Research

Scientists on an expedition to the underexplored Bounty Trough off New Zealand have discovered around 100 new and potentially new ocean species.  

The three-week voyage on NIWA’s research vessel Tangaroa was the first flagship Southern Hemisphere expedition for Ocean Census, a global alliance to accelerate the discovery and protection of life in the ocean founded by The Nippon Foundation and UK ocean exploration foundation Nekton.

The team of scientists from NIWA and Te Papa in New Zealand collaborated with experts from the UK and Australia to collect almost 1800 samples from as deep as 4800 metres underwater along the 800-kilometre-long Bounty Trough. 

Ocean Census Science Director Professor Alex Rogers, who co-led the expedition, says he’s been impressed with the sheer biodiversity of life they’ve discovered.  

“It looks like we have a great haul of new, undiscovered species. By the time all our specimens are examined, we will be north of 100 new species.  But what’s really surprised me here is the fact this extends to animals like fish – we think we’ve got three new species of fish.”

Voyage co-leader NIWA marine biologist Sadie Mills says the expedition has shown the Bounty Trough is flourishing with life. 

“We’ve gone to lots of different habitats and discovered a whole range of new species, from fish to snails, to corals and sea cucumbers – really interesting species that are going to be new to science.

“Ocean Census has enabled us to explore an area of Aotearoa’s deep seafloor that we previously knew little about in terms of the animals that live there. 

“This partnership will not only add new species to our recently published New Zealand marine biodiversity inventory, but will improve our understanding of the seafloor habitats and living geographic and depth ranges of rare species.”

A global team of scientists is working to confirm the finds at taxonomic workshops at NIWA and Museum of New Zealand Te Papa Tongarewa. Over the next three weeks they are sorting and describing the specimens collected, so they can be added to the picture of Aotearoa New Zealand’s marine biodiversity. 

New species identified so far include dozens of molluscs, three fish, a shrimp, a cephalopod and a new genera of coral. One find is baffling the experts.

Queensland Museum Network Taxonomist Dr Michela Mitchell says the voyage team initially thought it might be a seastar, a sea-anemone or zoanthid-like creature, but it has so far proven to be none of those.  

“We’ve got a lot of experts here having a look who are very excited.  

“We now think it could be a new species of octocoral, but also a new genus [wider grouping of species]. Even more excitingly, it could be a whole new group outside of the octocoral. If it is, that is a significant find for the deep sea and gives us a much clearer picture of the planet’s unique biodiversity.” she says. 

Prof. Alex Rogers says the Ocean Census NIWA Bounty Trough Expedition has met the ambition of a fully collaborative research mission aimed at discovery of new species in the ocean. 

“The partnership with professional scientists from NIWA and Te Papa and the ship’s crew from the RV Tangaroa has led to a transformative change in our understanding of this remote part of the ocean and the species that live within it, leaving a fantastic legacy for the people of New Zealand.” 

Andrew Stewart, Curator Fishes, Te Papa, reflected on the exciting expedition and the vastness of the area explored. “It was a privilege to collaborate with NIWA and Ocean Census. While our findings are significant, we know that we’ve barely scratched the surface of the Bounty Trough – there’s a whole other world of fauna still waiting to be discovered.”

Dr Thom Linley, Curator of Fishes, Te Papa, is still buzzing from the expedition. “Despite being a rōpū of experts, each team found something unexpected and exciting that they couldn’t wait to share.”

The specimens collected will be housed in the NIWA Invertebrate Collection and National Museum of New Zealand Te Papa Tongarewa in their Mollusca and Fish Collections.  The knowledge gained from the expedition will be included in future editions of the New Zealand Marine Biota NIWA Biodiversity Memoir, which was recently published by NIWA and represents our knowledge of biodiversity in Aotearoa New Zealand to date, currently comprised of 18,494 known living species.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Much of the central and western North Island saw significant rainfall totals of 40-75 mm in the past week.
• However, amounts were more modest in regions such as Northland, Auckland and Bay of Plenty, where rainfall totals were generally 25 mm or less. Meanwhile, only meagre rainfall was observed along the east coast of the North Island.  
• This resulted in small to moderate soil moisture increases across much of the North Island, most notably in central and western regions. However, some additional soil moisture decreases occurred from Hawke’s Bay to Wairarapa.   
• The driest soils across the North Island, when compared to normal for this time of the year, are found in the Far North, while the wettest soils for this time of the year are found in western and southern Waikato.
• Hotspots are currently located across the Far North and eastern Northland, coastal Gisborne, and from southern Hawke’s Bay to Wairarapa.
• As of 6 March, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in Northland, Auckland, part of the Coromandel Peninsula, eastern Bay of Plenty, and much of the lower North Island. Very dry to extremely dry conditions are located in eastern Northland, far southern Manawatū-Whanganui, and Wellington.

South Island:

• Rainfall amounts of 40-100 mm affected the West Coast and Tasman in the past week, with a few areas receiving more than 100 mm.
• Although Southland received 25-40 mm, the upper and eastern South Island saw generally meagre rainfall amounts of 5-15 mm.  
• This resulted in moderate soil moisture increases along the West Coast, but the east coast generally saw small additional decreases.   
• The driest soils across the South Island, when compared to normal for this time of the year, are found across parts of Canterbury, while the wettest soils for this time of the year are found in western Southland.  
• Hotspots are currently located across much of the upper and eastern South Island, including eastern Tasman, Nelson, parts of Marlborough, a majority of Canterbury, and eastern Otago.
• As of 6 March, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in eastern Tasman, Nelson, Marlborough, northern and far southern Canterbury, and eastern Otago. Very dry to extremely dry conditions are located in Nelson, Marlborough, northern and far southern Canterbury, and northern Otago.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 6 March, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in Northland, Auckland, part of the Coromandel Peninsula, eastern Bay of Plenty, much of the lower North Island, eastern Tasman, Nelson, Marlborough, northern and far southern Canterbury, and eastern Otago. Very dry to extremely dry conditions are located in eastern Northland, far southern Manawatū-Whanganui, Wellington, Nelson, Marlborough, northern and far southern Canterbury, and northern Otago. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• High pressure is expected to bring mostly dry weather to the North Island through Monday (11 March).
• The chance for a few showers will increase on Tuesday and Wednesday (12-13 March), but any rainfall will likely be light.
• Mostly dry weather becomes favoured again during late next week.
• Weekly rainfall totals of 15 mm or less look to be widespread across the North Island in the next week. In addition, regions such as Northland and Bay of Plenty could receive less than 5 mm.
• Due to the expected rainfall in the next week, substantial soil moisture decreases could be widespread across the North Island in the next week.
• Current hotspots across the North Island will have a good chance to strengthen and expand in the next week, particularly those in Northland where weekly rainfall could be especially meagre.

South Island:

• Other than a few showers in Southland on Friday night, high pressure will bring dry weather to the South Island through Sunday (10 March).  
• A front will bring moderate to heavy rain to the lower West Coast on Monday, followed by a stronger front from late Tuesday to Wednesday (12-13 March) that will bring at least some rain to a majority of the South Island, including heavy rain for parts of the West Coast.
• Scattered showers may return by next Friday (15 March).  
• Weekly rainfall totals of 75-125 mm are possible in the lower West Coast, with 40-75 mm in the upper West Coast.
• While Southland may again see moderate weekly totals of 25-40 mm, rainfall amounts of 10-25 mm are likely across much of the upper and eastern South Island.   
• Due to the expected rainfall in the next week, additional soil moisture decreases are possible in the upper and eastern South Island, but the lower West Coast and Southland may see small soil moisture increases.
• The current hotspots in the upper and eastern South Island could strengthen and expand at least slightly in the next week, but the changes may not be substantial.

Long-term outlook (through early April):

• The drier (25^th percentile) and middle (50^th percentile) rainfall scenarios both show drier or much drier than normal conditions across much of the country, especially in the North Island and upper South Island.
• In the wetter (75^th percentile) scenario, below normal rainfall is still forecast in isolated areas, but near normal rainfall is most favoured across the country.
• Very dry soil conditions could affect the lower North Island and eastern South Island in all three rainfall scenarios, along with parts of the upper and eastern North Island in the drier scenario. The middle and drier scenarios also show the possibility for a small area of meteorological drought to form in the lower South Island.

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

A culmination of over 45 years of research is painting a grave picture for the state of our iconic glaciers.

NIWA’s Dr Andrew Lorrey says that hotter temperatures are to blame.  

“We’ve had a flurry of harsh summers and repeated marine heatwaves that have caused warm air to cook our glaciers. As part of our annual snowline survey, we’ve documented ice cover for the Southern Alps since the late 1970s by taking aerial photographs of the snowline position at the end of summer.  

“These photos are then put into a 3D model pioneered by Dr Lauren Vargo and Associate Professor Brian Anderson from Te Herenga Waka—Victoria University of Wellington, which shows how glacier volume has changed. This collaboration has provided us with a long, nearly unbroken record of ice loss,” said Dr Lorrey.

NIWA estimates that at least 13 trillion litres of water have been lost from our iconic New Zealand glaciers since the late 1970s. This is the equivalent of nearly five decades of basic household water use for the whole country. 

In addition, NIWA has recently worked with a landscape art historian Dr George Hook to study 19th Century paintings by artist John Gully, which captured ice retreat already underway in the mid-1800s. “The paintings were intended to convey the dramatic scale of a mysterious land far away from industrialised British society. They show vast and vivid snow cover across New Zealand’s mountains and documents the beginning of their retreat.  

“Serendipitously, for contemporary scientists, comparing these artworks with current photos vividly shows the magnitude of ice loss that has occurred since the mid-1800s,” said Dr Lorrey.   

Simultaneously, researchers based at University of Otago and Victoria University of Wellington have conducted a programme measuring glacier change at Brewster Glacier, located in Mount Aspiring National Park, since the early 2000s.   

Professor Nicolas Cullen from the University of Otago is part of the team. His work involves snow probing and installing ablation stakes into the ice with a steam drill to measure how much snow and ice is gained and lost over each season.

“Our unique long-term observations on Brewster Glacier have led to it becoming a global benchmark for understanding how glaciers in the Southern Hemisphere are responding to climate change,” says Professor Cullen.  

Dr Shaun Eaves from Victoria University of Wellington has been doing similar work around the summit of Mt Ruapehu. He says the findings tell a similar story.

“We;ve done mapping around the summit region of Mt Ruapehu and its showing the same pattern as the Southern Alps, with small glaciers there disappearing fast.  

“Many are reduced to slivers of ice covered with a thin veneer of debris. All suggestions point to some going extinct in the years ahead,” says Dr Eaves. 

While the overall findings are bleak, Dr Lorrey says there is still time to make a difference. 

“These fantastic collaborative efforts from scientists across New Zealand show that our our beautiful glaciers have taken a beating, but if we act quickly, we can limit even more damage. We are writing the script as we are living the story, and we are in charge of the outcome. If we want future generations to experience what we have, we must get on top of this now by reducing carbon emissions to halt the increase in global warming.” 

More information: Frozen in time: old paintings and new photographs reveal some NZ glaciers may soon be extinct (The Conversation)

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Much of the North Island saw rainfall totals of 10-25 mm in the past week, with parts of the central North Island receiving 25-40 mm.
• However, areas in the Far North and Wairarapa saw more meagre amounts of 10 mm or less.
• This resulted in small to moderate soil moisture increases in the central North Island in the past week, while other areas generally saw little change.  
• The driest soils across the North Island, when compared to normal for this time of the year, are found in the Far North, while the wettest soils for this time of the year are found in southern Waikato and western Taranaki.
• Hotspots are now located across much of Northland, northern Auckland, northern Coromandel Peninsula, East Cape and coastal Gisborne, coastal Manawatū-Whanganui, and Wellington-Wairarapa.
• As of 28 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in Northland, Auckland, part of the Coromandel Peninsula, eastern Bay of Plenty, East Cape, and much of the lower North Island. Very dry to extremely dry conditions are located in eastern Northland, far southern Manawatū-Whanganui, and Wellington.

South Island:

• Rainfall amounts of 25-60 mm affected the West Coast and Tasman in the past week, with isolated areas receiving 75 mm or more.
• However, the rest of the South Island saw generally meagre rainfall amounts of 5-15 mm.  
• This resulted in small to moderate soil moisture decreases across a majority of the South Island.  
• The driest soils across the South Island, when compared to normal for this time of the year, are found in northern Tasman, while the wettest soils for this time of the year are found in western Southland.  
• Hotspots are currently located across much of the upper and eastern South Island, including eastern Tasman, Nelson, Marlborough, northern and southern Canterbury, and eastern Otago. In addition, central Canterbury and interior Otago are close to hotspot status.  
• As of 28 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in eastern Tasman, Nelson, Marlborough, northern and far southern Canterbury, and northern Otago. Very dry to extremely dry conditions are located in Nelson, Marlborough, northern and far southern Canterbury, and northern Otago.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 28 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in Northland, Auckland, part of the Coromandel Peninsula, eastern Bay of Plenty, East Cape, much of the lower North Island, eastern Tasman, Nelson, Marlborough, northern and far southern Canterbury, and northern Otago. Very dry to extremely dry conditions are located in eastern Northland, far southern Manawatū-Whanganui, Wellington, Nelson, Marlborough, northern and far southern Canterbury, and northern Otago. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• Mostly dry weather is expected through Saturday, but a front will bring periods of moderate rain to the western and northern North Island on Sunday (3 March).
• Monday (4 March) looks to be very wet across the island, with widespread moderate to heavy rainfall.
• After a few more showers on Tuesday (5 March), the next few days are expected to be dry once again.
• Widespread weekly rainfall totals could reach 30-50 mm in much of the central and western North Island, with some areas potentially receiving 50-80 mm. However, parts of Northland and the east coast may see substantially less rainfall, in the range of 20 mm or less.
• Due to the expected rainfall in the next week, substantial soil moisture increases may occur in western and central regions, while parts of Northland and the east coast may see additional decreases.
• The current hotspots in Northland and the eastern North Island could see additional strengthening in the next week, but in Auckland and Manawatū-Whanganui the hotspots may ease somewhat.

South Island:

• Some showers will affect the West Coast and lower South Island during the weekend (2-3 March), but other areas will be dry.  
• Low pressure will bring moderate to heavy rain to much of the island on Monday (4 March), with the West Coast and lower South Island seeing additional showers on Tuesday.
• Thereafter, mostly dry weather is expected during mid-to-late next week.  
• Weekly rainfall totals of 75-120 mm are likely in the West Coast, including Fiordland, with 40-60 mm for Southland and interior Otago.
• However, regions such as Nelson, Marlborough, and Canterbury will likely see lighter rainfall totals of 10-25 mm.   
• Due to the expected rainfall in the next week, additional soil moisture decreases are possible in the upper and eastern South Island (especially near the coast), but the West Coast and lower South Island may see soil moisture increases.
• Most current hotspots may strengthen in the next week, although those in Otago may ease at least slightly. However, additional hotspots may form in central Canterbury.

Long-term outlook (through early April):

• The drier (25^th percentile) and middle (50^th percentile) rainfall scenarios both show drier or much drier than normal conditions across much of the country.
• Even in the wetter (75^th percentile) scenario, below normal rainfall is still forecast in isolated areas, but near normal rainfall is most favoured across the country.
• Very dry soil conditions could affect the lower North Island and eastern South Island in all three rainfall scenarios, along with the upper North Island in the drier scenario. The drier scenario also shows the possibility for a small area of meteorological drought to form in the lower South Island.

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

A brief Q&A with Caroline Chin, a Marine Biology Technician with NIWA.

What is your role on the Ocean Census voyage?

I am primarily helping with recording and preserving specimens that are collected from the various sampling equipment we have. I record the data into a collections database so that we can track and locate our samples in the future. I also help with recording DTIS observations on the seafloor, as well as processing sediment from the multicorer.

 

What is it like observing the DTIS? Can you describe the deployment?

It can be a mixed bag of exciting and not-so-interesting observations, so it can either feel like time flew by very quickly or it dragged on for too long when there was nothing but muddy sediment and burrows. The deployment starts off with testing the camera before it goes over the side and then towed alongside the boat. Once it hits the bottom, we use software to record what substrate and benthic fauna we see along a given transect by watching a low-pixel resolution screen in the lab. A DTIS transect usually takes about an hour. It takes a team of three to run the deployment: one to oversee that DTIS is working smoothly, another to call out animal observations and one to record these observations.

What happens with the animals when we get back to Wellington and why is this work important? (naming the NIC).

The animals are stored at the NIWA Invertebrate Collection (NIC), one of the few nationally significant natural history collections here in New Zealand. The animals will eventually be identified by world-class taxonomists from New Zealand and other parts of the globe, then properly curated on our collection shelves for further research such as genetics, eDNA, etc. These animals will further enhance our understanding and appreciation of the biodiversity found on the seafloor in the Bounty Trough.

You’ve been on a lot of voyages! How many have you been on and what are some highlight moments?

I have been on 16 voyages. Some highlights on my trip were doing two submersible dives (1800 m and 6300 m) in the Kermadec Trench as well as seeing a humpback whale in Antarctica breaching close to the boat when setting up a Continuous Plankton Recorder (CPR) on the fantail.

You get excited when you see animals, why is that, what intrigues you about marine animals?

Animals come in all forms of cute, beautiful, ugly, bizarre, and horrifying! I grew up in Borneo, a biodiversity hotspot in Southeast Asia, so my fascination for the weird and wonderful fauna from rainforests came from an early age. As for marine animals, I am impressed and perplexed that they can survive in harsh environments like the deep sea with cold temperatures, food scarcity, and high hydrostatic pressure.

I hear you have started your PHD – what are you researching?

I am investigating benthic faunal patterns in the Kermadec Trench using video imagery and applying artificial intelligence (or deep learning) in my PhD project.

How can AI help ocean science?

It can be used as a tool to help with complex tasks or making sense of large amounts of data that are challenging for humans to analyse and process quickly. For example, for underwater imagery, manual annotations have been used to label animals in videos and photographs. However, human annotation is tedious and time-consuming, especially when a lot of imagery is collected. A one-hour video can sometimes like 3 days to analyse! Using AI can help quicken the process, so that scientists can focus on other scientific tasks rather than spend hours counting thousands of animals on a video transect.

What is your favourite animal?

I have many favourites in the marine world. Currently, it is the numbfish because it looks like a real-life electric Pokémon – apparently it can give quite a jolt despite looking like a harmless blob. Otherwise, my all-time favourite animal is Mourka, my 11-year-old tabby who is cross-eyed, has 4 teeth and gives great high fives.

Source: NIWA – National Institute of Water and Atmospheric Research

Scientists are seeing more toxic algae in our lakes and rivers compared to previous years, says NIWA.  

New Zealand’s warm, stable summer has created ideal conditions for the growth of the algae, also known as cyanobacteria, which can be harmful to people and animals as it may produce toxins. 

Algal Ecologist Karl Safi says that his work through NIWA’s Algal Services, which monitors, samples and analyses water sources for these outbreaks, has increased significantly.

“Warm, calm waters help this type of algae, commonly referred to as blue-green algae, to thrive. Shallow lakes and slow-moving rivers and streams being particularly susceptible, especially when the weather is hot. Bodies of water in the central North Island have seen a particularly dramatic increase in cyanobacterial blooms,” said Dr Safi.  

Cyanobacteria play a crucial role in our ecosystem but become a problem when found in high concentrations because of the toxins they can produce. These cyanotoxins can have health risks for people and animals if exposed through touching or swallowing contaminated water and breathing in droplets of contaminated air.   

Symptoms include irritation of the skin, eyes, and lungs, as well as stomach pain, headaches, diarrhoea, and dizziness. For animals such as dogs, cyanobacteria can be life threatening within a few hours.  

“We ask that people keep an eye out for lakes or ponds that are discoloured, cloudy or murky, especially if blue-green in colour or with a scum on the water’s surface or edge. In rivers, toxic algae generally form brown or black mats that grow on rock. There may also be a strong odour.  

“We don’t want to worry people, but instead help them be more aware when enjoying the outdoors this summer. So, if you notice any of these signs, be cautious when going in or near the water, and take special care of any pets,” said Safi.  

Visit NIWA’s Algal Monitoring Service for more information.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• Much of the North Island saw meagre rainfall totals of 5 mm or less in the past week, with a few areas seeing no rainfall at all.
• A few localised areas in the Coromandel Peninsula and Central Plateau saw amounts of 10-30 mm.
• This resulted in additional moderate to large soil moisture decreases across the entire North Island.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in eastern Northland and the Coromandel Peninsula, while the wettest soils for this time of the year are found in southern Waikato.
• Hotspots are now located across much of the North Island, including Northland, Auckland, northern Waikato, Bay of Plenty, East Cape and coastal Gisborne, coastal Taranaki, Manawatū-Whanganui, and Wellington-Wairarapa.
• As of 21 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Northland, Auckland, eastern Bay of Plenty, East Cape, and much of the lower North Island. Very dry to extremely dry conditions are located in eastern Northland, far southern Manawatū-Whanganui, and Wellington.

South Island:

• Rainfall amounts of 20-40 mm affected the West Coast in the past week, although Fiordland received 75-150 mm.
• However, the rest of the South Island saw meagre rainfall amounts of 10 mm or less, with some locations receiving no rainfall at all.  
• This resulted in moderate soil moisture decreases across nearly the entire South Island.  
• The driest soils across the South Island, when compared to normal for this time of the year, are found in Nelson, Marlborough and northern Canterbury, while the wettest soils for this time of the year are found in western Southland.  
• Hotspots are currently located across much of the upper and eastern South Island, including eastern Tasman, Nelson, Marlborough, northern and southern Canterbury, and eastern Otago. In addition, central Canterbury is close to hotspot status.  
• As of 21 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in eastern Tasman, Nelson, Marlborough, northern and far southern Canterbury, and northern Otago. Very dry to extremely dry conditions are located in Nelson, Marlborough, northern Canterbury, and northern Otago.

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 21 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Northland, Auckland, eastern Bay of Plenty, East Cape, much of the lower North Island, eastern Tasman, Nelson, Marlborough, northern and far southern Canterbury, and northern Otago. Very dry to extremely dry conditions are located in eastern Northland, far southern Manawatū-Whanganui, Wellington, Nelson, Marlborough, northern Canterbury, and northern Otago. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• After isolated showers on Friday (23 February), mostly dry weather is expected on Saturday.
• A front will bring moderate rainfall on Saturday night and Sunday morning to many regions.
• While Northland may continue to see showers on Monday, the rest of the island will be generally dry on Monday and Tuesday (26-27 February).
• After a few showers on Wednesday, late next week will be mostly dry.
• Weekly rainfall totals could reach 20-30 mm in parts of the northern and central North Island, with generally less than 20 mm elsewhere.
• Due to the expected rainfall in the next week, small soil moisture decreases may occur in drier parts of the island, although little change is expected in areas that see higher rainfall amounts.
• The current hotspots in the North Island will likely not change much in the next week, although those in areas that see less rainfall may strengthen slightly.  

South Island:

• A front moving up the South Island on Saturday (24 February) will bring moderate to heavy rain to the West Coast, Southland, and Otago.
• After dry weather on Sunday and Monday, an additional round of showers or rain may arrive on Tuesday (27 February).
• Thereafter, generally dry weather is expected through late next week.  
• Weekly rainfall totals of 70-100 mm are possible in the lower West Coast, including Fiordland, with 30-40 mm in the upper West Coast and lower South Island.
• However, regions such as Nelson, Marlborough, and Canterbury will likely see lighter rainfall totals of less than 15 mm.   
• Due to the expected rainfall in the next week, additional soil moisture decreases are likely in the upper and eastern South Island, but the lower West Coast and lower South Island may see small increases.
• Current hotspots may strengthen in the next week, while additional hotspots may form in central Canterbury.

Long-term outlook (through late March):

• The drier (25^th percentile) and middle (50^th percentile) rainfall scenarios show drier or much drier than normal conditions across much of the country.
• In the wetter (75^th percentile) scenario, below normal rainfall is still forecast in isolated areas, but near normal rainfall is most favoured.
• Very dry soil conditions could affect the lower North Island and eastern South Island in all three rainfall scenarios, along with the upper North Island in the drier scenario. The drier scenario also shows the possibility for a small area of meteorological drought to form in the lower South Island.

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

A weekly update describing soil moisture patterns across the country to show where dry to extremely dry conditions are occurring or imminent. Regions experiencing significant soil moisture deficits are deemed “hotspots”. Persistent hotspot regions have the potential to develop into drought.

Recent rainfall and current soil moisture conditions:

North Island:

• It was a dry week for the North Island. Several stations recorded no rainfall, including parts of Auckland city, Hamilton, Taupō, Hick’s Bay, Whakatu (near Hastings), Levin, and Masterton.
• Due to afternoon showers on 9 February, some sites recorded totals over 30mm in the Central North Island, including Okahune and Taurmaranui.
• This resulted in widespread soil moisture decreases across North Island.
• The driest soils across the North Island, when compared to normal for this time of the year, are found in eastern Northland, while the wettest soils for this time of the year are found in southern Waikato.
• Hotspots have expanded over the last week and are currently located in much of Northland, northern Bay of Plenty, East Cape, parts of Wellington-Wairarapa and coastal Manawatū-Whanganui.
• As of 13 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Northland, Auckland, and much of the lower North Island. Very dry to extremely dry conditions are located near the Bay of Islands, southern Manawatū-Whanganui, and Wellington.

South Island:

• Widespread rainfall amounts of more than 50-150 mm affected Fiordland in and West Coast in the last week, with the heaviest totals across the Alps and ranges. Milford Sound recorded 141 mm, with 119 mm falling in a day. Areas near the coast received 10-50 mm, with Hokitika receiving 1 mm.
• Lower Southland received 10-40 mm, such as Invercargill receiving 12 mm, and some showers delivered 1-10 mm to parts of Otago, including Queenstown which observed 7 mm, with Cromwell and Alexandra observing 2 mm apiece.
• Some showers about Canterbury were heavy last weekend, and delivered 10-30 mm to some areas. Kaikōura received 25 mm in a day, about half of their monthly normal, but was otherwise dry. Lincoln near Christchurch recorded 20 mm in a day last weekend, but was otherwise dry.
• However, much of the week was dry, and large parts of Tasman, Nelson, Marlborough, and Canterbury were either dry or received less than 5mm.
• Soil moisture decreases were generally observed everywhere except parts of north Canterbury and Southland.  
• The driest soils across the South Island, when compared to normal for this time of the year, are found in Nelson, Marlborough, and parts of eastern Otago, while the wettest soils for this time of the year are found in Southland.  
• Hotspots have emerged in eastern Tasman, Nelson, Marlborough, and eastern Otago.
• As of 13 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in Tasman, Canterbury, and eastern Otago. Very dry to extremely dry conditions are in eastern Tasman, Nelson, Marlborough, parts of Canterbury, and northern Otago. Previously observed areas of meteorological drought have dissipated but may return in the next week.  

Pictured above: Soil Moisture Anomaly Maps, relative to this time of year. The maps show soil moisture anomalies over the past two weeks.

As of 13 February, the New Zealand Drought Index (NZDI) map below shows that abnormally dry conditions are currently found in parts of Northland, Auckland, much of the lower North Island, Tasman, Canterbury, and eastern Otago. Very dry to extremely dry conditions are located near the Bay of Island, southern Manawatū-Whanganui, Wellington, eastern Tasman, Nelson, Marlborough, parts of Canterbury, and northern Otago. Previously observed areas of meteorological drought have dissipated but may return in the next week. Please note: some hotspots in the text above may not correspond with the NZDI map. This difference exists because the NZDI uses additional dryness indices, including one which integrates the rainfall deficit over the past 60 days. Changes are therefore slower to appear in the NZDI compared to soil moisture anomaly maps that are instantaneously updated.

The week ahead:

North Island:

• The week ahead looks mostly dry again, aside from the chance of some showers.
• Afternoon showers and isolated thunderstorms look to occur for the central and lower North Island this weekend (16 – 17 February).
• Showers look to become more widespread on Monday through to Wednesday, first affecting western areas, then eastern areas later.
• Weekly rainfall totals look to reach 5-15 mm for many areas, although some areas that get several rounds of showers could see as much as 20-30 mm.
• Otherwise, some areas in the lower North Island may only receive 5 mm or less.
• Due to the expected rainfall in the next week, moderate soil moisture decreases may occur in much of the North Island, although generally minor change is expected in central regions.
• The current hotspots in eastern could both strengthen further in the next week.

South Island:

• This weekend (16-17 February) looks to be generally dry, aside for the chance of isolated afternoon showers for some inland areas.
• Widespread rainfall look to affect Southland and West Coast from Monday, with some areas of lighter rain and showers with possible thunderstorms for Otago and eastern Canterbury Monday – Wednesday. Some of these showers and thunderstorms could bring some heavier, but brief, rainfall.
• After that, conditions will quickly dry out again, with settled weather for the remainder of the week.
• Weekly rainfall totals look to be 50-100 mm for parts of the elevated West Coast and Fiordland, with 5-15 mm for Southland.
• Showers and thunderstorms associated with a southerly change on Monday – Wednesday could bring up to 30 mm to some isolated areas in Otago, Canterbury and eastern Marlborough, but otherwise less than 5-10 mm is predicted.
• Many areas look to be largely dry for the entire week, including Nelson, parts of Tasman, parts of Marlborough, parts of Canterbury, and parts of Otago.
• Due to the expected rainfall in the next week, additional soil moisture decreases are likely in the for much of the South Island, except Southland where soil moisture will remain the same or slightly increase.
• Hotspots will likely worsen in the next week.

Long-term outlook (through mid-March):

• The drier (25^th percentile) and middle (50^th percentile) rainfall scenarios show drier or much drier than normal conditions across nearly the entire country.
• Even in the wetter (75^th percentile) scenario, below normal rainfall is still forecast for several regions across both islands.
• Such agreement across all three rainfall scenarios gives an increased confidence in drier than normal conditions in the coming weeks.
• Very dry soil conditions could continue to affect the lower North Island and eastern South Island in all three rainfall scenarios, along with the upper North Island in the drier scenario. Small areas of meteorological drought could occur indicated in parts of Wairarapa and the eastern South Island in the drier scenario.

Pictured above: 35-day forecast rainfall anomaly scenarios (Top), and 35-day forecast dryness and drought scenarios (Bottom). These maps are updated daily at https://niwa.co.nz/climate/seasonal-climate-outlook 

Background:

Hotspot Watch: a weekly advisory service for New Zealand media. It provides soil moisture and precipitation measurements around the country to help assess whether extremely dry conditions are imminent. 

Soil moisture deficit:  the amount of water needed to bring the soil moisture content back to field capacity, which is the maximum amount of water the soil can hold.

Soil moisture anomaly:  the difference between the historical normal soil moisture deficit (or surplus) for a given time of year and actual soil moisture deficits.

Definitions: “Extremely” and “severely” dry soils are based on a combination of the current soil moisture status and the difference from normal soil moisture (see soil moisture maps at https://www.niwa.co.nz/climate/nz-drought-monitor/droughtindicatormaps)

Hotspot: A hotspot is declared if soils are “severely drier than normal” which occurs when Soil Moisture Deficit (SMD) is less than -110 mm AND the Soil Moisture Anomaly is less than -20 mm.

Source: NIWA – National Institute of Water and Atmospheric Research

NIWA scientists leading Aotearoa New Zealand’s MethaneSAT agricultural emissions science programme are gearing up for the launch of its satellite in coming weeks. 

MethaneSAT is a global initiative led by the US Environmental Defense Fund to track and reduce methane emissions around the world. 

The US project is focused on methane leaks from oil and gas production, while the New Zealand-led agricultural programme is studying global emissions from agriculture, such as ruminant farming and rice production.

Science leader for the agricultural programme, NIWA’s Dr Sara Mikaloff-Fletcher, says the state-of-the-art satellite is unique, because it can measure over a large area and map methane at high spatial resolution and unprecedented precision.

“MethaneSAT will give us the type of data that we could never get from ground-based measurements. It will map methane over 200 by 200 kilometre regions, and it will be able to detect as few as two parts of methane per billion when averaged over a 1km spatial resolution.

 “MethaneSAT will be the first satellite well suited to quantifying diffuse agricultural emissions, due to its high precision and spatial resolution. We have the opportunity to be the first team to develop and prove this capability worldwide,” says Dr Mikaloff-Fletcher.

New Zealand provides the perfect test ground for the MethaneSAT agricultural programme, because it has an unusual greenhouse gas profile and world class greenhouse gas measurement and modelling capability. While carbon dioxide (CO2) is the most important greenhouse gas for most developed countries, New Zealand’s biggest source of emissions is methane and the lion’s share of that comes from agriculture. 

“If you are developing something very new, it is essential to prove it works. We will have a field campaign in New Zealand to measure methane emissions at the surface and from aircraft to test this capability,” says Dr Mikaloff-Fletcher. 

Atmospheric researchers on the project have been laying the groundwork since 2021, developing and testing models that will help them make sense of the satellite data, preparing and testing instruments that will be used to validate satellite information on the ground, and identifying the best places for the satellite to measure agricultural emissions around the world. Post-launch, access to data from the satellite scanning the atmosphere will herald an exciting new stage in the research.   

New Zealand has a long history of world class greenhouse gas measurements and modelling.  For example, NIWA’s atmospheric observing site at Lauder is one of the two founding Total Column Carbon Observing Network sites, which are the gold standard for validating greenhouse gas observing satellites, including MethaneSAT. 

“This capability positions us beautifully to ground truth our results. We will prove this capability in New Zealand, to demonstrate that measurements made at other locations around the world can be used with confidence,” says Dr Mikaloff-Fletcher.

The agricultural research programme is a collaboration between experts across New Zealand, including NIWA, Manaaki Whenua Landcare Research, University of Waikato, and Victoria University of Wellington, and the US based science team at Harvard University, EDF, and Smithsonian Astrophysical Observatory. The project is funded by the Ministry for Business, Innovation and Employment. Partners RocketLab and the University of Auckland’s Te Pūnaha Ātea-Auckland Space Institute are establishing and operating mission control for the satellite.