Te Arawa/Rotorua lakes field work – a PhD students perspective
I’m sitting on the plane, on the way home to Adelaide trying to sum up the Rotorua field trip. This field trip was my first time in the field for the Lakes 380 project. When I came to New Zealand last year, I was pleased with the amount of sightseeing I managed to cram in while visiting Rotorua for 3 days and felt that I had “seen the place”. Well, I was wrong.
I didn’t quite realise how many lakes the Rotorua region had to offer. The lakes we all worked on throughout the 10 day field trip varied from small basins, such as Lake Okaro and Lake Ngahewa, to whoppers like Lake Tarawera and Lake Okataiana. We sampled lakes with clear, blue water (Lake Tikitapu), and we sampled lakes that were quite green (see algal blooms) (sorry, Lake Rotoehu and Lake Rotoiti). Yet, all of the 12 lakes we visited had their own charm and were memorable for various reasons.
Photo caption: A memorable lake: Lake Tutaeinanga, which was surrounded by farmed land. We were greeted by curious cows while packing up. They licked the boats and the car.
Many of the lakes in the Rotorua region were affected by the Mount Tarawera eruption in 1886, and in-fact are underpinned by this event. This became apparent when the lakes were cored and the cores would reveal depositions of volcanic mud and tephra (ash). For some lakes, cores couldn’t be taken beyond the Tarawera eruption, while other lakes cores collected were able to push through the volcanic mud layer to ultimately reveal lake conditions (when they are analysed) before the Tarawera eruption.
Do I have a favourite lake? I don’t per se, but the one that captured my attention the most was Lake Okataina. The drive to it was a road of native forest. The lake itself, however, was surrounded by steep cliffs covered in the native forest…I never get tired of seeing tree ferns. This lake was also the lakes where things went wrong. We were out there for nearly 4 hours. I think both the water quality and coring boat found this. Everything was just made difficult by the fact the lake was 80 m deep (I think we sampled to 63 m). So, if we weren’t successful in coring, or surface sediment sampling we had to drop it down again and again. Yet, being out in the middle of the lake was so quiet and serene (I don’t use this word often), and while pulling up a difficult sample, and feeling the pain in your shoulders and forearms, it paid to look up, look around, and take in the surroundings. It’s not every day that one can have an office like this.
Photo caption: Lake Rotoiti , the last lake we sampled on the field trip. It felt great to finish here as the sun was coming down.
Of course, scenery and awe aside, this field trip was also a great learning opportunity for me. I have gathered ideas (almost too many) for my PhD, I have learned about volcanoes, associated jargon, and their effects on lake environments, I can use fun tools (Ponar, surface sediment corer, phytoplankton and zooplankton nets) to get water quality samples, and I have seen a part of New Zealand that is often missed out on the tourist trail. I’m excited to now be a part of the Lakes 380 project and look forward to investing the next few years of my life in it.
– Julia Short, PhD student, Adelaide University
Summary from Te Arawa/Rotorua lakes field work
Ngāti Tahu and Ngāti Whaoa mana whenua welcomed the Lakes380 team at Lake Ōkaro, opening our Te Arawa/Rotorua lakes fieldwork with karakia timatanga. Others from Te Arawa Lakes Trust, Tuhourangi Tribal Authority, GNS and Cawthron Māori Relationship Advisers, and a local farming family joined us for whakawhanaungatanga. Following mihimihi and kai whakanoa we ventured on to the water where mana whenua observed first-hand the collection of a sediment core about 1.5 m in length.
Over the following nine days the Lakes380 team collected sediment cores and water samples from a further 11 Te Arawa lakes; Lake Tikitapu, Lake Okareka, Lake Ngapouri ,Lake Tutaeinanga, Lake Rotoehu, Lake Okataina, Lake Tarawera, Lake Rerewhakaaitu, Lake Ngahewa, Lake Rotorua and Lake Rotoiti. We were lucky to mostly have great weather which allowed us to sample at depths up to 70 m (lakes Tarawera and Okataina). We also equally enjoyed exploring some of the lesser known smaller lakes in this region; Ngapouri, Ngahera and Tutaeinanga.
One of the unique aspects of the cores from this region was the presence of large tephra’s (layers of volcanic ash). In most cores the Tarawera tephra (1886) was clearly visible (e.g., see photograph of the core from Lake Rotoehu below). In some cores the team speculates we can see the Kaharoa tephra, which is from an eruption of Mt Tarawera about 1314. This eruption spread ash the eastern and northern North Island. This layer is an important marker for paleolimnological studies because it approximately corresponds to the start of human occupation of New Zealand. In addition to having these ‘markers of time’ in the cores, the team is very interested to see how the in lake biological community’s and processes respond to these catastrophic natural disturbances that essentially reset the lakes.
The team extends a huge thank you to the Te Arawa Trust for their guidance and support, and the BOP regional council for their generous assistance with logistics and boating.
Day 2 – Te Arawa/Rotorua lakes
Social scientists at work: Kiely McFarlane beside Don Stafford’s archives of Arawa history. Te Whare Korero o Don Stafford, Rotorua Library, 1 April 2019. Photo: Charlotte Šunde.
Lakes380 – Te Arawa/Rotorua lakes
Ngāti Tahu and Ngāti Whaoa mana whenua welcomed the Lakes380 team at Lake Ōkaro, opening our Rotorua Lakes fieldwork with karakia timatanga. Others from Te Arawa Lakes Trust, Tuhourangi Tribal Authority, GNS and Cawthron Māori Relationship Advisers, and a local farmer who has supported wetland restoration joined us for whakawhanaungatanga – engaging on and off the water. Following mihimihi (introductions) and kai whakanoa (refreshments), we ventured on to the water where mana whenua observed first-hand the extraction of a sediment core. On shore, the splitting of the core revealed a distinct layer of grey ash from a sequence of Mount Tarawera eruptions. We are grateful to mana whenua for taking time from their busy mahi to support us, and we wish them a wonderful opening of their whare tīpuna, Rahurahu, at Waimahana Marae on Saturday 20th April. Kia ora koutou!
Record (for Lakes380) 2 m long sediment cores were retrieved….with Tarawera tephra/ash starts about 50 cm down the core.
Southland – That’s a Wrap
– Katie Thomas PhD Student
When you’ve just got married and driven hundreds of kilometres down the wild West Coast of the South Island, you’d think it’s quite hard to top such experiences. I won’t say it was better than my wedding day… but flying over the endless fiords as the sun breaks over the horizon to land in some of the most untouched places in NZ… that’s something pretty darn special!
Left: Sunrise over Lake Te Anaua from helicopter. Right: Sean searching for signal, Lake Lucille.
Arriving at the tail end of a monumental field campaign, still riding the hearty highs of our wedding day, I wasn’t convinced I was a welcome sight to the weary field veterans of Te Anau. But there’s nothing like a beautiful deep blue lake with Kea flying overhead to reinvigorate even the most fatigued of field teams. I was lucky enough to join the final helicopter day out to Lakes Lucille and Troup, to the west of Te Anau, near the top of Doubtful Sound. Flying over the Wilmot Pass, we reached the edge of Doubtful Sound, lined with waterfalls washing over the edges of countless river valleys cut short by a long-gone glacier. Getting a bird’s eye view of these dramatic landscapes really helps put into perspective the large-scale process that create them, as well as the much grander geological timescales in which we must consider them. As a biologist, you tend to think about the tens, or sometimes hundreds, of year it takes for organisms to cause change to a landscape. But these rivers have existed for possibly millions of years, to then be gouged out by a giant chunk of ice during a glacial period some 18,000 years ago. This is precisely why we appreciate the knowledge and perspectives that our colleagues at GNS, Victoria and Otago Universities bring to Lakes380.
At a dizzying depth of 98 m, Lake Troup was by far our deepest lake across all regions visited so far – the next closest being Lake Lockett (57 m; Nelson/Tasman region) and the Acheron Lakes (54 m) east of Te Anau. This should not have been too surprising, looking at the sheer cliff faces surrounding us. Despite our best efforts to retrieve at least some form of core sample, the best we could get were some chunks of boulder…which just goes to show, sometimes lakes are like a box of chocolates…we never really know what we’re going to get! I have a feeling we will back here one day, next time with some serious coring equipment!
From left (clockwise): Outlet of Lake Troup looking across the top of Doubtful Sound and end of the Wilmot Pass at the many waterfalls. Left: Attempting to retrieve a Ponar grab sample at approx. 42 m. Middle: The resulting grab. Right: Lake Troup’s cool, clear water surrounded by vertical rockfaces.
Our last day of sampling in Fiordland threatened to bring wet, cold and miserable sampling conditions as we drove the long gravel roads out to South Mavora Lake. But we were pleasantly relieved of this by the time the boats were ready to launch. A misty and magical place, it is in fact one of many sites of pilgrimage for LOTR fans. No Hobbits, Orcs or Urak-hai were spotted unfortunately, though some of the grunts and contorted faces of core retrieval could have been mistaken for some undesirables of Mordor…
Left: Glassey water and stunning mountainous view down the Mavora valley. Right: Successful core retrieval.
It might seem unfair to give all the attention to the beautiful and dramatic landscapes of the high-country lakes, but I can’t say I wasn’t saddened to leave them behind as we headed further south to the big smoke of Invercargill. It was here I reminded myself that the whole reason I started my journey as a freshwater scientist was to help understand and restore these highly impacted lowland waterbodies. I had to repeat this mantra many times over as we battled the soft, gumboot-swallowing mud of Lake George, a 0.9 m deep coastal lake west of Invercargill, near Colac Bay. Thankfully the other three lakes were more forgiving but similarly shallow. What I can say for the southern plains is, what they lack in picturesque, clear lakes, they make up for in hospitality and cheese rolls – a classic Invercargill delicacy. And who knows, perhaps these sediment cores will reveal some intriguing untold tales when we cast a finer eye over them back in comfort of the lab.
From left (clockwise): Big Lagoon proving wetland lakes can be pretty too. Left: Putting the 4WDs through their paces at Lake George. Middle: Lake George putting the team through their paces, and a lot of mud. Right: Smile, it’s the last Lake! Waituna Lagoon.
-Rose Gregersen- PhD Student, Auckland University
The Southland field trip began for me with a nightmare flight into Invercargill, and ended with no desire whatsoever to head back home to Auckland.
This immense trip was an immense success. Thanks to hours and hours of organisation and preparation, seamless team work and leadership, the team was able to sample a total of forty lakes. Many of these lakes are in as close to un-impacted condition as possible and the cores collected will provide important long-term records of climatic change and reference ecosystem state.
With much of Southland being inaccessible by road, our main mode of transport to and from site was Helicopter. Not only did this serve us amazing views but also gave me immense awe for those travelling the Pounamu trail by foot hundreds of years earlier. Wanting to make the most of helicopter time we aimed to sample two lakes per day in fine weather. Adding on the time between lakes for cleaning, pack down and setup makes for long days in the field – Lucky the team is made of determined, hardworking and passionate people.
I think the breath-taking scenery is partly responsible for this determination – no one was particularly keen to take their scheduled days off. It often felt as though my eyes were deceiving me, the landscape serving as a constant reminder of the importance of Lakes 380
– John Pearman – Molecular Ecologist, Cawthron Institute
It had all started two weeks earlier when I arrived in New Zealand to start my career at Cawthron. Now I was heading south for my first experience of sampling the lakes of New Zealand in Southland.
My first experience of the sampling was an early morning start to meet the helicopters that would take us up towards the alpine zone and the first lake of the day. We rose up over the mountains with lakes emerging in the bottom of the valleys.
After a short flight we descended through the clouds and set down next to the lake side. We wrapped up warm to protect against the morning chill and as soon as the sling arrived with our equipment we got down to the business of constructing the inflatable boats. It was not long before the sun broke through the cloud, allowing the far side of the lake to be observed and a sweat to be brought about as we prepared for the upcoming paddle. With the sun beating down, the only similarity to my previous sampling experiences in Saudi Arabia, the smaller inflatable was the first to venture out onto the water. After a bit of paddling around, not quite in circles but almost, the deepest part of the lake was identified and the larger inflatable (Kea), on which the coring took place, maneuvered into position. While those on the coring boat used their brawn to tap the corers into the sediment the action on the smaller boat was slightly more sedate taking samples for water quality analysis. These included: nutrients, total and dissolved organic carbon and trace metals as well samples for zooplankton and phytoplankton. Finally, not to miss out on the fun of playing with sediments, a ponar was deployed to sample surface sediments. With the all samples on board and the coring team having pulled up four cores it was time to head back to shore and collapse and clean the equipment before the short, yet scenic, hop across to the second lake of the day where the whole process was repeated.
A speck in the vast expanse. The coring boat positioned at the deepest part of the Lake Roe to collect sediment cores.
The next couple of sampling days took place on more lowland and potentially anthropogenically impacted lakes. These two lakes were situated on farms in the Te Anau region and would provide a variety in the lake conditions sampled when considered alongside those in the alpine zone. At the first lake after meeting the farm owner and discussing his philosophy on farming and taking advantage of his local knowledge of the system the team headed down to the lake, hefted the equipment over the barbed wire protecting the lake and started unintentionally chasing the paradise shelducks around the lake in the name of science. The second lake down in the lowlands followed a similar procedure, although without the shelducks leading the way. In preparation for heading back up into the mountains a healthy dose of bleach was used to make sure the equipment was extra clean so as to avoid cross contamination of the delicate systems.
The next day started with another scenic helicopter trip (note to any budding future (or current) scientists out there…. choose your sampling field sites well). The team settled into the pattern of constructing, the boats, sampling and then dismantling and cleaning the inflatables and another two lakes were ticked off.
The next day though was not quite as uneventful. Firstly, the first lake sampled had a sandy beach from which the boats were launched. It was also the first time I had properly been stationed on the coring boat and had to use muscles that had long been forgotten about. Four cores later and am arms wondering what I had against them, we started the paddle back to shore into the strengthening breeze just to make sure that the upper body had had a proper work out and arrived just in time for the what seemed like lunchtime for the sandflies. The second lake was to bring the true excitement and will go down in Lakes380 folklore as the lake of the flying eel. The sampling went off without a hitch, with some good 1.8 m + cores obtained. As the boats were dismantled and cleaned, Jamie was down at the water edge cleaning his gloves when a post watershed shout was heard. An eel was seen gracefully arcing through the air, a position it was most likely unfamiliar with, before gravity got the better of the situation and the eel landed in the grass. It turned out that the eel had decided to take an opportunistic nibble at Jamie’s finger and this had led to the spontaneous flight lessons for the eel. The good news though is that after the recovery from the shock and disbelief both the finger and eel survived the episode.
The next lake to be sampled brought its own perils. Those of frisbees as equipment was carried across a frisbee golf course in Te Anau. Luckily this time no one was hurt in the pursuit of science and the sampling of the small Lake Henry proceeded with no dramas.
The last lake of my time in Southland also happened to be the most scenic and deepest I had sampled. The helicopter flight brought us into a bowl with steep sides encompassing most of the lake.
With Kea’s circling above the boats headed out onto the tranquil lake and started to sample the 50 m water column to obtain the water quality samples as those on the coring boat heaved up four long cores from the depths. With the sampling complete for my time in Southland all that was required now was to pack up and have one final scenic helicopter ride back.
The Lakes380 team heads north to Auckland
The third installment of Lakes380 field sampling brought the team to Auckland’s dune lakes.
First up was and environmental DNA survey at Tomarata Lake, which lies on the edge of Mangawhai forest. Being away from laboratory facilities can be difficult, but the team is comprised of well-experienced problem solvers, and an improvised motel laboratory was quickly constructed and day one ended with a late night of sample processing.
Day two we returned to Tomarata to collect sediment cores and water quality samples. Close by Lake Spectacle was next on our list. Getting stuck in the mud here tested our four-wheel drive capabilities (or should I say, our ability to read rental car manuals, how many scientists do you think it takes to switch over to four-wheel drive?).
We cruised through day three at the beautiful Lake Kareta in South Head; smooth sailing credited to the fantastic facilities, company, and kai provided by Ed and Nicole Donald who are passionate about the future of this lake.
After refreshing our forestry safety protocols on the morning of day four, we headed further up South Head to sample in the footsteps of Kawheru the giant; lakes Rototoa and Kuwakatai. Rototoa lived up to its namesake of “strong lake”, challenging us to a tug of war over the first core. It seems our determination convinced the lake to return the corer with core intact, along with what felt like permission to continue sampling. After Rototoa we ventured into the forest to peaceful Lake Kuwakatai. Unable to launch the motor boat, we paddled the raft out managing to complete all our sampling from one vessel.
The final day took us south to Lake Wainamu, a unique lake surrounded by beautiful native bush and towering black sand dunes. Access to the lake would have been impossible without the expert ATV dune driving skills of Harry from Auckland council. With help from Kevin Simon (Auckland University) and Matt Bloxham (Auckland Council) we sampling and pack down went super smoothly and was the perfect to end a successful trip.
One of the really fantastic aspects of this project is meeting and talking with members of the community, people who are passionate about the health of Aotearoa’s lakes. There are some stories lake sediment cannot tell.
Captions (clockwise): Susie and Andrew work late into the night filtering eDNA samples (but remain happy). Rose field sampling. The ATV loaded and ready for the sand dune trip. Sampling Lake Wainamu.
Caption: The Lakes380 Auckland sampling team with Ed and Nicole Donald in front of Lake Kareta.
Caption: The Lakes380 Auckland sampling team with Harry and Matt (Auckland Council) in front of Lake Wainamu.
See the Lakes380 team in action in this short video from Golden Bay
Sampling Golden Bay/Mohua – part 2
The quest to sample our 380 lakes continued last month when the crew headed over the Takaka Hill to Golden Bay. Lakes Rototai, Killarney, Otuhie and two of the Kaihoka lakes were ticked off the list early in the week (read more about these sites in Charlotte’s post below). We like to refresh the field crew to keep energy and momentum going on these lengthy and often remote field trips, so I tagged in for the second half of the trip.
The much-anticipated first heli-sampling day of the project finally arrived, bringing a stunning day of sampling on Lake Lockette in the Kahurangi National Park. Despite the picturesque surrounds, this was no holiday for the sampling team. At approx. 700 m wideand 57 m deep, Lake Lockette proved to be a physical challenge, taking over 5 hours to complete the full suite of sampling
Unfavourable weather the next day meant no heli-action, but the sampling didn’t stop. We headed northwest to the shallow, low-lying Lake Mangarakau. Wind and dark cloud descended over us making for some slow paddling progress. Having two inflatable vessels certainly makes it possible to access a range of remote lakes – but, on days like this you really miss an outboard motor!
The second chopper trip took us back into Kahurangi National Park to the much smaller and shallower Lake Peel – tucked in a mountainous bowl over the ridge from the Cobb Valley. We swooped in and got our sampling done in under three hours, but had to pack up and get out smartly before the cloud, rain and hail set in from the northeast. We better get used to these unpredictable mountain conditions for our Southland campaign, where over half of our lakes will be heli-access only!
Stay tuned for our next adventure before a well deserved christmas break, this time further north in the Auckland region. – Katie Brasell
Sampling Golden Bay/Mohua – part 1
Lakes380 launched our fieldwork in Mohua/Golden Bay with Manawhenua ki Mohua at a small blue lake, Rototai, near Takaka township. Karanga, karakia and waiata rang out in greeting to the lake and the tūpuna connected to this rohe; a karakia timatanga led by Te Ātiawa, Ngāti Tama and Ngāti Rārua whānau. It was very uplifting for all involved and opened pathways for a deeper connection to lakes and the stories accumulated within layers of whakapapa and sediment deposits. In the afternoon, we drew cores from Lake Killarney in Takaka – a small suburban lake where locals recall childhood memories of playing in the waters which are now regarded as unsafe for submersion.
Over the following few days, the team cored the two Kaihoka Lakes at Westhaven Inlet in northern Golden Bay. David Ferguson, whose family has farmed there since 1915, led us across rolling hill country through multiple farm gates on beautiful lush land where his son now farms 1700 sheep. These coastal lakes are surrounded by dense bush with grand nikau palm trees protruding like a sentinel presence, causing me to ponder who is the observed and who the observer.
Another cancelled helicopter trip meant that we made an unplanned diversion to take sediment cores and water samples from Lake Otuhie. Access was challenging and required digging a slipway by hand to launch the dinghy and inflatable canoe onto a flax-flanked creek. As we entered the wide amphitheatre of Otuhie, it felt as if the scars of separation between Ranginui and Papatūānuku were still raw, in a slow process of healing. Muscular limestone bluffs towered above, softened by the green cloak of Mother Earth, and as we worked the tears of the Sky Father fell gently upon us.
- Charlotte Šunde, 6/11/2018
(Clockwise) The Lakes380 team prepare at the edge of the Kaihoka lake a, surface sediment from Kaihoka 1, Lake Peel and the outlet of Lake Otuhie.
Lakes380 Launching Off in Wellington!
Our Lakes380 campaign began in earnest last week when the team descended upon Lake Waitawa, near Otaki, to collect our first samples in the Wellington region. The team included eight people, two boats, and three vehicles packed to the brim with all manner of equipment. Our mission: to collect all samples and clean down within half a day.
The first lake was always going to be a learning experience; the loose soupy mud and thick algal blooms at Lake Waitawa presented some logistical challenges. Nearby Lake Waiorongomai, a shallow coastal dune lake, was our second target and the first test for our shiny, new, red inflatable raft – would it fit the bill for those remote South Island lakes, accessible only by helicopter?
While the GNS Science crew retrieved four long cores from the lake bed, the rest of the team listened intently to some great korero from local kaitiaki, Caleb Royal – tales of how his ancestors once fished thousands of tuna (eels) from Waiorongomai and would bathe in its water to wash away the blood and anguish of battle on their journeys home.
Next stop was the Wairarapa and Lake Nganoke, a small shallow lake on private land in the south Wairarapa. Our sampling efforts on here saw us finishing in approximately 5 hours. We even had time to pick up a few extra samples from a very glassy, picturesque Lake Wairarapa (pictured above).
With some great improvements in coordination and teamwork we were starting to look like a pretty slick operation. The inflatable boat will be a great assets for the helicopter trips in the coming months, with the possible addition of a second smaller raft to speed up the process. Next on the agenda – sunny Nelson/Tasman! Watch this space for more updates in early November.