It has been a while since I wrote a blogpost. A lot of fun and time-consuming things have happened in the meantime which kept me from writing a blogpost (yeah yeah, it’s a bad excuse). First of all, Paola, my partner came to Sydney to visit me for 7 weeks over February and March. The weather was terrible but we did get to see a lot of great things in and around Sydney. I will write a separate blogpost about that at some point. The other exciting thing that happened was that I got to do the first experiment of my PhD! And that is what I want to dedicate this blogpost to.
As you may know, I was not very lucky in terms of my time of arrival in Sydney at the end of June 2021. I went straight into a COVID lockdown that lasted until November, and I couldn’t go to the university, let alone run an experiment. So when that was finally over, it was time to get away from my desk and over to the Sydney Institute of Marine Science (SIMS). This beautifully located institute in Sydney harbour has a great aquarium facility and that’s where I ran my experiment.
For this experiment, I was interested in the role below-ground microbes play in the performance of seagrasses when under stress from a marine heatwave. Interestingly, not much is known about the importance of below-ground microbes for seagrasses, especially not in the context of environmental change. There are indications that below-ground microbes indeed play an important role, similar to terrestrial plants, but so far there have been no experiments testing this. Coming from a terrestrial background, where the importance of the soil for plant health is now widely recognised, I felt like we should look into this more for seagrasses.
But why bother, you may ask? Seagrass meadows are incredibly important ecosystems that provide numerous benefits for other marine organisms by providing food or shelter, including for those cute seaturtles and dugons. They also protect our coasts from storms, and sequester large amounts of the carbon that we’re all happily emitting. If these microbes indeed play an important role in the health and functioning of seagrasses, and if the interactions between seagrasses and their microbes change under environmental stressors such as marine heatwaves, then this may have cascasing effects throughout the ecosystem which could impact a lot of marine organisms and humans that depend on them. So yeah, seagrasses are kind of a big deal.
Unfortunately, these important seagrasses are, like many other organisms in the world today, not doing very well in a lot of places. Coastal development, water pollution and climate change is causing them to dissappear at a rate of 20,000 soccer fields a year since the 1980’s (I know, that’s a lot…). You don’t hear so much about this compared to the loss of coral reefs or tropical rainforests, but they are in fact on of the most threatened ecosystems in the world. Many ongoing restoration efforts have only had limited success and we need to know more about their ecology to be able to improve and upscale restoration.
So for my experiment I compared the growth of seagrasses under different temperature treatments while also manipulating the presence and absence of belowground microbes in the sediment and on the roots. I have to say that I was feeling pretty nervous before starting. I like to plan everything in detail and prepare everything as much as I can to make sure things run smoothly, but since this was my first seagrass experiment there were a lot of unknowns for me. Deep down I knew I would pull it off, but still. I definitely learned that marine experiments are a lot harder than terrestrial ones. There are so many more things to take into account when it comes to fieldwork such as the weather, visibility under water, safety issues, and damn sediment is a lot heavier than soil! And I’ve lifted lots and lots of kilo’s of soil before. Then when trying to keep the seagrasses alive it’s not just a decent amount of water and light (and good soil of course) that they need like terrestrial plants, no no, you need to keep track of the pH, temperature, and salinity of the water, the right light intensity and flow rate of the water. And then there’s algae that start to grow in places you don’t want them. Oh boy, oh boy, these babies definitely kept me busy! On top of that, there were also machines breaking down, delayed deliveries and me getting COVID right before the start of the experiment. What a ride!
It was a lot of hard work, but luckily all went well, and I’m now analysing the first data that I collected. There are some interesting results already, but for that you’ll have to wait. The next step, is to extract DNA from the samples I collected to see if the microbial community composition changed in response to the different treatments and whether that might explain the health and growth of seagrasses. But first, I’ll be going to Europe for almost 2 months in 1.5 week. I’ll be working from there but also going for a holiday in Italy together with Paola. Very much looking forward to that! And I might even see some beautiful Posidonia while I’m there 😉