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Bioinspiration Expedition 2019 – Log 4

Single image from a series images that are part of a 3D reconstruction of Phronima inside a salp. The laser illuminates only a slice of the subject, allowing us a unique look inside. Phronima’s head is visible on the left, as well as several pairs of claws and swimming appendages (right). All that’s left of the salp is the elliptical structure surrounding the parasite.

Bioinspiration Expedition 2019 – Log 4

 

A Phronima amphipod inside its salp house, as captured by the main camera of MBARI’s ROV Doc Ricketts.

Hi, I’m Joost Daniels and I’m a research tech in the Bioinspiration Group. In true Bioinspiration fashion, my main job on this week-long cruise consists of two parts: bringing the lab to the ocean, and bringing the ocean to the lab. For the former, we’ve brought our DeepPIV instrument along, mounted on the remotely operated vehicle (ROV) Doc Ricketts, for deep-sea flow measurements. DeepPIV uses a laser to illuminate a thin sheet of water, showing the movement of particles in the water. In conjunction with a dedicated camera we can use it to study animal kinematics and the way animals use and modify water flow to their advantage.

Single image from a series images that are part of a 3D reconstruction of Phronima inside a salp. The laser illuminates only a slice of the subject, allowing us a unique look inside. Phronima’s head is visible on the left, as well as several pairs of claws and swimming appendages (right). All that’s left of the salp is the elliptical structure surrounding the parasite.

One example of an animal we’ve looked at with DeepPIV on this cruise is an alien-like crustacean in the genus Phronima. It is a hyperiid amphipod and has a big head, multiple jointed appendages, and sharp claws. If that wasn’t enough, its lifestyle completes the nightmare: it will find a salp, eat the salp’s insides, and then take up residence inside the zombified host, and even lay eggs in there. The amphipod continues to swim around with its head inside the salp, and that’s how we often encounter them in the deep sea.

We have also taken the ocean to the lab, in the form of five combinations of instruments that allow us to do various types of imaging, including two that employ lasers and cameras like DeepPIV does, but with high-speed cameras to reveal fast and fine-scale motion. This also enables us to do 3D reconstruction of certain semi-transparent subjects. So far, we’ve been using these setups for a range of subjects including various siphonophores and Tomopteris worms; we even made a 3D reconstruction of a Phronima. We are hopeful we’ll find a few more interesting targets in the coming days.

Cruise participants looking at a siphonophore that is prepped for flow analysis in one of the laser-based lab experiments. Top, left to right: Kakani Katija (MBARI), Diana Li (Hopkins Marine Station), Joost Daniels (MBARI). Bottom: Alex Hoover (University of Akron).