From helping with the gold clam survey on Lake Rotomanu in Taranaki, to being at the Ruakura campus looking at carophytes, macrophytes, wastewater treatment and clam experiments. Eleanor Thorpe writes a blog on her time as a BLAKE Freshwater Ambassador alongside Anna Meikle for Earth Sciences New Zealand.
Day 1
Anna and I started the day going to ‘Earth sciences New Zealand’s’ main office. Here we did a few rounds of introductions and got a health and safety run down. We then went along to ‘Earth sciences New Zealand’s Ruakura research facility. We were sorting the turions of the common pond weed / curly pond weed or Potamogeton crispus. Turions are shoots which are capable of growing into a full plant The two turion morphotypes are called ‘denticulate’ or ‘spiculate’. 60 samples had been taken from lake Horowhenua down in levin. The Levin city council had contracted NIWA to write a weed management plan. So understanding the various growth forms are important.
We separated the Denticulates and Spiculates and then put these into tin foiled little bags that we had previously weighed out the weight for and then put all our little bagged samples in a big oven to dry.
Figure 1 – Anna sorting the turions
Day 2 Tuesday 9th December
We spent today at the Ruakura Research facility again. Today we were tackling cleaning out two of the tanks where the plant team do plant growth trial.
We stopped at 10 and had a chat with “Dr Deborah Hofstra” we talked a bit about the work of the plant team at NIWA. invasive species. The things you have to think about when managing them, the downstream impacts, the context, funding, the goal, what is already known/ being done.
We spent most of the day cleaning these two big tanks. It was really fun actually. It was a really hot day so we had fun in the water. We rescued two frogs. At the end of the day Rupert showed us a bit of his waste water chemistry. He was working on a couple of samples of waste water from a brewery.
Day 3
Today we were on the Ruakura site again. In the morning we were recording the dry weight of the turions we did on the first day. After we smashed that out we finished off cleaning the two tanks we started yesterday. We used a water vacuum cleaner!!
Figure 2: Anna with the underwater vacuum cleaner.
Day 4:
Today Anna and I were extremely excited as we got to work on the Benthic Barrier research for the Golden Clams. We were helping Yuri in the morning with her experiments.
We started off with collecting samples and doing a bit of lab work for the waste water treatment experiments. The experiment uses algae for the treatment of waste water and is trying to see if starved algae will take more nutrients from the water.
Then we helped out with the Benthic barrier experiment for the golden clams. The experiment aims to find control methods to stop this invasive pest. The benthic Barrier method is trying to work out how long the golden clams can survive without oxygen to try and find a sweet spot where we can kill the clam and / or suppress the clams with the least amount of harm to our native clams and tuna and lampreys and other freshwater native ecology. This was day 20 of the trial so we were counting and measuring how many dead clams from deprived oxygen tanks.
After that Densise came in and taught us how to ID viable spores for Caryophytes. We then worked our way through tank 1 to ID viable spores. Amazingly these samples had been collected 15 years ago!
Figure : microscope image of viable Carophyte spores
Figure : Eleanor taking water samples from the benthic Barrier trial dead clam water.
Day 5:
We started our day bright and early today. At 5:15 am in the morning we were picked up by Inigo and Orlando. We drove out to the Waihi Estuary near Maketu beach (along pukehina parade).
We were doing some monitoring of a seagrass restoration site. This project is working alongside local iwi to restore the health of this estuary. The estuary has lost 90% of historic seagrass covering. The estuary is really impacted by the surrounding farming and agricultural activity in the surrounding area. There are 5 rivers that feed into this estuary. Inigo and Orlando had planted two seagrass sites in October and are monitoring them monthly until February. When we walked out to the sites you could see the impacts of the sedimentation and bad health of upstream waterways. Not only was there very clear sedimentation and debris, massive chunks and piles of invasive fresh water plants had washed into the estuary. There were also algae blooms growing on the seagrass and cockle beds. However, despite all that the seagrass restoration site was growing well! We waded out in our waders and measured the plots and took data from the planting site to gather data on the growing rate and health of the seagrass planting. Sea grass restoration is apparently very hard and has a low success rate. The first site there had been a lot of growth out. The second site had less new growth but interestingly the blades themselves were much longer (almost double in length)
Figure : (from left to right) eleanor and Anna collecting the seagrass replanting data
Figure : (from left to right) Orlando, eleanor, Anna and Indigo out crossing the waihi estuary.
Day 6:
We drove to Taranaki this morning. We arrived at the main site at 8am. Then we drove to Taranaki. We arrived here at about 12:30. When we arrived it was all hands on deck. There were lots of people from DOC, and the Taranaki regional council. When we arrived they were draining the lake. This had been happening over the weekend. However not all of the lake was able to be drained in time. So there was a change in plans as to what was going to happen to the fish. Originally they were going to harvest them all and drain the lake even more completely. But because they couldn’t get the water low enough and its Christmas break next week. They decided to leave it at the level it was. (So about ¾ maybe emptied). The plan was to do a delimiting survey around lake rotomanu to get an understanding of the clams spread. Together with a team from the Taranaki city council we worked together taking transects, and surveying quadrants in sample sites. Sifting for the clams. We found about 20ish in the first site, 2 in the second site and maybe 2 in the last sample site.
We started in the area where the clams had been found. (By the boat ramp). To take the transects we measured out a line of 50 meters then took quadrants, (as many that were possible) randomly from the 0, 25 and 50 meter marks. We worked in pairs to sift through the substrate searching for clams. The kid ‘Max’ who was the one who spotted and positively IDed the golden clam in Laka Rotomanu also popped in for a bit.
When we moved on to the final site we were going very slowly, but by this time the Taranaki regional council workers had gone home. By about 6 we decided to call it a day and find our accommodation. Sifting was like panning for gold. We were panning for the golden clams!
Day 7:
Day seven was our big day in Taranaki. We started our day at 7 to find food for the day. We arrived on site at 8am. We got all kitted up in our clam sifting gear. Today was forecasted to be cold and very wet. By 8 am had already rained on and off and was for sure drizzling.
We knew we had a lot of things to do today so we locked in. We had a new team with us from the Taranaki regional council.
We were continuing with the delimiting survey we had started the day before. We wanted to do sites all around lake rotomanu to get a spatial area distribution of the invasion and spread. We worked all around the lake. This took about 6/7 hours.
By around 3 we started Kick net samples to get an age – size class distribution in the areas the clams were most dense. This was around the boat ramp.
The team also placed Dissolved Oxygen probes at sites around the lake. All of this is to get an understanding of the clams invasion of this new location. But also gather information about the site itself. The size data will tell us a bit about how long the clams had been in the lake. And the distribution will give us information of the extent of the invasion. As well as how the clams may behave in different environments. The dissolved Oxygen probes will monitor the water, and give information about the lake health and quality.
Day 8:
Today was Wednesday. We gathered all our data on Monday and Tuesday. The taranaki trip was a success. So we piled into the 2 NIWA utes at 7am this morning ready to make the drive back.
We arrived back at the main site at 11 ish. We unpacked and put everything dirty into the massive walk in freezers. Then Anna and I cracked into the Taranaki Clam data. We worked through the field notes for the rest of the afternoon. Trying to decipher some of the field notes was certainly a puzzle!
Day 9:
Today we worked on the clam data again in the morning. Then clam benthic barrier work. Today was day 30. We then cleaned some of the gear we had taken to taranaki. Then went to Bobs landing with Michelle. Ground zero, now very changed. Littered with clams. Water clarity has changed so much. The water is way clearer. Then back to the office and worked on more clam data.