Steaming home

Following the recovery of the last sediment trap at 0800 this morning, we began to steam back to Oahu. Over the course of the cruise, as we have chased current-carried sediment traps, we have strayed from our original position, making the voyage home about three hours longer. Some researchers continue to finish up experiments even as others begin packing.

On the research front, the Van Mooy and Webb labs are squeezing in one last collaborative experiment on Trichodesmium, nitrogen-fixing bacteria that are colonized by heterotrophic (non-photosynthesizing) bacteria. Throughout the cruise, the Webb lab's classification of the yield of Trichodesmium colonies in their net tows has escalated from "motherload" to even greater colloquial terms of abundance. This is good news for others on the ship who have benefited from the Webb group's generosity with their bounty. On the chemistry side, the Van Mooy lab is incubating the colonies with signaling molecules that may regulate enzyme activity responsible for nutrient metabolism in the heterotrophic bacteria that colonize Tricho. The excitement this morning upon seeing statistically significant results from an enzyme assay experiment conducted Tuesday to Wednesday easily overshadowed the delight surrounding yesterday's impromptu crate/tarp spa construction. We squeezed in one last net tow, Lily quickly picked another round of Tricho, and we set the Tricho symbionts incubating with some signaling molecules. The enzyme assays tomorrow morning could help explain some aspects of Tricho nutrient use that have long puzzled scientists.