Day (11) and (12) – 77 days after deployment

The last two days at the field site were a whirlwind of sediment coring, carbonate chemistry sampling, bacteria sampling, tracer sampling, and, of course, the grand finale—removing all the equipment. The first day was a carbonate chemistry sampling. Armed with syringes, we collected around 180 samples from 12 plots at 5 depths, with 3 replicates per plot. Samples were filtered underwater, pH was measured on the boat, and total alkalinity awaited its turn in the lab. Reigning over this operation was Damon, taking over pH measurements that day, perched on his high throne and bravely enduring the gruelling task of waiting for pH readings to stabilize… in near-perfectly calm conditions. He declared it the hardest job of the day. The jury is still out. The plots visually looked similar with a layer of potentially dead algae and no olivine or aglime minerals to be seen be the naked eye. The following day was physically labour intensive. We hauled up 36 sediment cores, sieving them right on the boat to preserve the epifaunal communities. Meanwhile, tracer samples were collected outside the plots—our last-ditch effort to track sediment movement and any lingering olivine. Then came the bittersweet moment—removing the equipment. A sign that the experiment had officially ended, but also the beginning of data analysis and discoveries! After an intense three-month experiment full of learning curves, we’re pumped to apply what we’ve learned and dive into the next one soon.

Marianne Pelletier, Feb 2025