Iron, together with other trace metals, is an essential micronutrient, required for the growth of all organisms, including phytoplankton that form the base of the marine food web. Given that phytoplankton convert CO2 into biomass that partly settles into the deep ocean, trace metals are key players in global climate. However, some key ocean regions remain understudied and various crucial processes remain poorly understood, making informed-policy decisions on climate strategies and management rather challenging. One of these understudied regions is the High Latitude North Atlantic, where phytoplankton and thus primary productivity is limited by the availability of iron. Since the high latitudes are changing rapidly, scientist are urged to understand how both current and future ocean changes effect global biogeochemical cycles, notably the marine iron cycle.
Consequently, the MetalGate team will collect samples for trace metals, various isotopes, nutrients, phytoplankton, and sedimentological parameters during the expedition to unravel the role metals play in this climate relevant region. The scientists will also conduct controlled bio-assays at ecologically relevant conditions to improve current understanding of the linkages between phytoplankton physiology and biogeochemistry in the high latitude North Atlantic. Samples will also be collected for colleagues from the USA, UK, Spain, Switzerland, and Brazil that cannot join the cruise, making this expedition a truly interdisciplinary and international endeavour. Insights from this work will enhance the understanding of local biogeochemical cycles and their connections to global cycles and thus climate. Such data will also result in better predictions of the likely impact, both now and in the future, of imminent Arctic and sub-Artic climate change on ocean health.
Wednesday 21 July 2021
The MetalGate Team is currently sampling their 3rd out of 40 stations during their 4 week long expedition in the North Atlantic. The team is set to sample the water column and sediments for trace metals, isotopes, ligands, and biological parameters, that is, phytoplankton in the surface ocean. Instruments are working, spirits are high, and the weather is good.
Tape on tape that is the only way
Quote of the day by Loay Jabre
Saturday 24 July 2021
By Anna Koek
When I was working with Willem on a project using a dataset from the Antarctic Peninsula almost 18 months ago, he at some point asked me if I would be in for some fieldwork experience. Without knowing what he was talking about, I said yes immediately! Of course I didn’t know that despite a slight delay due to some global pandemic, missing a plane and bags staying behind in Amsterdam, I would be cruising around Iceland on the Pelagia, investigating iron limitation in the Atlantic ocean this summer.
My first week ever on a research vessel has been amazing! We were escorted out of the port of Reykjavik by a couple of puffins and a fin whale, sampled 5 different stations, started and measured our first iron addition experiment and we were very lucky with the weather. As the biological team, we are only interested in the top layer of the ocean, where most biological activity takes place. That means most of the time we are waiting until the CTD has travelled 2000m to the seafloor and all the way up to the surface again, where we sample the top 50m for marine microalgae. In the mean time we help out the other teams, or, as they are very organized and usually don’t need much help, we sit in the sun and enjoy the view on the ocean and the occasional sighting of a pod of pilot whales. In about 4 weeks, when we set foot on land again, we hope to have gathered a lot of data that can tell us why marine microalgae are not reaching there full potential in the high latitude North Atlantic and what the role of iron in these waters is!
Saturday 24 July
By Rebecca Zitoun
We had a few hiccups along the way since the last blog post, starting at station 3 with a malfunctioning trace metal clean CTD (i.e. the custom built UCC from NIOZ). Luckily, we had all the necessary spare parts on board, thanks to NMF, and within hours, our all-rounder chief scientist, Rob Middag, together with the Pelagia crew, got the instrument working again. We had to make up for the lost time though by skipping station 4 and 5, but on the bright side the instrument is working very smoothly now and all the scientists had heaps of time to organise their workspace and prepare for station 6. We even had time to start the first of our five bioassays during transect while testing the UCC in deep water. The bioassays will look at the effect of iron addition, ammonium addition, and increased temperatures on prevalent phytoplankton. The bioassay will run for the next 4 days and the results will give us insights on how climate change will impact phytoplankton biomass and composition in the High latitude North Atlantic.
We also just finished the second successful deployment of our custom built Bottom-Gradient- Sampler (BGS). The BGS was built to sample the water column close to the seabed that can’t be reached by the CTD rosette. Hence, the collected water samples will give us a better understanding of the fate and cycling of trace metals in the lowest water column, close to the sediment.
We are now on transit to station 7 for another deployment of the UCC.
Video showing the BGS (bottom gradient sampler)
If it doesn't work, try and try again and if it still doesn't work, fix it, fix it and fix it.
Quote of the day by Sharyn Ossebaar