News • 10 September – 25 September 2020
Photos by Luis Montilla, Friederike Peiffer, and Lauren Arrington
Text by Luis Montilla
If you happen to spend some time in Naples, you will probably have the chance to taste a coffee prepared by a Neapolitan friend in a moka machine. It is likely that you will notice that before serving, they will stir the coffee inside the moka. When asked, they will tell you is that coffee is more concentrated at the bottom of the moka than at the top. By stirring it, they are doing you a favour! This mixing not only improves coffee, but similarly happens in nature when layers of different gases or substances are stirred in the air and in the water due to turbulence. Here we will tell you a little bit more about our fieldwork in the Posidonia oceanica meadows off Ischia Island last September and how this is related to stirring coffee.
From the SZN in Napoli, Dr. Ulisse Cardini, Friederike Peiffer and myself were accompanied by Laura Dennis, a Master student attending the IMBRSea Master Program, who joined us for an internship. We also joined forces with a team from the Max Planck Institute for Marine Microbiology in Bremen, Germany, composed of Dr. Dirk Koopmans, a postdoctoral researcher in the Microsensor group, and Lauren Arrington, a Master’s student in Marine Biology at the University of Bremen and student assistant in the Virology group at the MPI.
We conducted activities within the frame of an ASSEMBLE+ funded project, ECo-MOAR, aimed to perform eddy covariance measurements of seagrass metabolism in meadows exposed to reduced pH at CO2 vents off Ischia Island. This project was lead by Dirk, an expert in eddy covariance measurements, and Dr. Allison Schaap, a research engineer working on lab-on-chip technology for environmental sensing at the National Oceanography Centre, in Southampton, UK.
Dr. Ulisse Cardini, as the Person in charge from the SZN, took good care to make the campaign run successfully.
Posidonia oceanica, as any other plant, uses sunlight to generate its nutrients through photosynthesis. In the process, the plant takes up carbon dioxide and releases oxygen. The amount of carbon dioxide that a seagrass meadow can take up during the day can be considerable, to the point of altering the pH of the surrounding water. This is intriguing for scientists, since it may suggest that seagrass meadows can offer refugia to susceptible marine organisms from ocean acidification. Ischia Island offers sites where carbon dioxide is naturally emitted from the seafloor, acidifying the environment, which offer scientists a sneak peek into a potential future.
Dirk’s instruments simultaneously measured the concentration of dissolved oxygen and pH, as well as the direction and speed of turbulent motions moving in a circular fashion. These “eddies” have sizes ranging from that of ping pong balls to that of swimming pools! The term eddy “covariance” is used to indicate that to succesfully calculate benthic metabolism the method needs to quantify changes in concentration and water velocity at the same time, and how each relate to the other. The lab-on-chip sensors simultaneously measured chemical variables (pH, alkalinity), using minimal power and reagents. Finally, Friederike and Laura were using special chambers secured to the seafloor to measure seagrass community metabolism on a smaller and confined scale for the project eMBraCE, about which you can read more here.
For all of us it was an exciting opportunity to use different techniques and state of the art sensors to measure seagrass metabolism underwater. For many reasons! Not only we could continue doing the eMBraCE experiments in a different site, but we could also work with some really sensitive sensors to understand much more about how seagrass responds to changes in light, pH, and other factors.
Field work always brings some challenges too, which made our experience memorable.
For example, more often than not we had heavy underwater currents, which can be great for eddy covariance but incredibly tiring when you have to carry heavy equipment underwater! Also, visibility underwater is reduced compared to that out of the water, particularly so when currents are strong. Getting lost in those occasions is a matter of seconds! All the while, you will also need to be coordinated and in constant communication with your teammates on the boat to pull the instruments out of the water as delicately as possible.
Luckily, these troubles were not the norm, and we could also enjoy some sunny Mediterranean fieldwork days in the stunning seagrass meadows off Ischia.
Collaborations like this are very important in science and give us the opportunity to complement data sets and to learn from each other. Laura and Lauren gained valuable experience for their future careers while we benefited from their support to run the experiments. Here’s more from Laura’s perspective:
“It was such a great opportunity to be working in this team, where we had two very interesting projects going on in a unique location. I was excited! The opportunity to examine this unique naturally acidified environment was very interesting, and I loved being able to work in these large seagrass meadows surrounded by bubbles from the CO2 vents. The questions and topics brought up by the leading scientists of the team were always very stimulating. I learned a lot from them while living and working together, trying to absorb as much of the knowledge they shared as I could.
I feel that I got a well-rounded experience of being part of a scientific field campaign with the challenges and victories that go along with it. There were days with difficult conditions for diving that made some tasks difficult, which was good training for me to learn how to handle diving with strong currents and low visibility, while also carrying equipment or trying to complete tasks. Other days, everything went perfectly smooth. We were able to work through all the challenges that came up and sometimes the solutions made the project even more fun! Such as having to change our research vessel several times until we ended up in a beautiful 100-year-old wooden sailboat. Or when one of the scientists had to go on what seemed like a “Mission Impossible” mission back to land for a missing replacement part for his high-tech instruments. I was always impressed by how the PIs made things work out in the end. Through this collaboration I got hands-on experience about in situ studies with seagrass, which I was able to follow up in the lab, and I also learnt about new innovative instruments. I feel very lucky to have worked in such a beautiful place with such a strong and supportive team. It was an invaluable learning experience that I am grateful for.“
Special thanks to: Pietro, Filippo and Virginia Ferrandino for all their help and good disposition during our days working together.