|Photo strip showing a dumbo octopus and a sea cucumber|
Autosub has been deployed with two cameras. The downward facing camera takes photos directly below Autosub, and these photos are used to assess the number and types of invertebrates that live on the seafloor in different areas of the plain. Sea cucumbers are the dominant type of large invertebrates that we see in the abyss, and there are at least ten different varieties in our photos. Autosub takes one photo every 0.8 seconds, so the photos overlap. This overlap means that photos can be stitched together into long strips, giving a continuous picture of the seafloor. In just a few days, we have taken more than 300,000 photos with the downward camera, which will take months to analyse!
The forward facing camera is being used to look at the numbers and distribution of abyssal fish. Fish decline in number rapidly with depth, with only a few species able to survive on the limited food supply in the abyss. The rarity and mobility of fish means that surveys must cover large distances to determine their distributions over the seabed, which is why Autosub is such a valuable tool. Fish species in the abyss look quite different from fish that you see at the fishmongers; they are dominated by eels and rattails, and are typically scavengers that can cover long distances using relatively little energy to try and find food. We need to use a forward-facing camera to monitor fish because they are mobile, so can be startled and swim away before being seen by the downward facing camera. So far, we have collected around 250,000 photos, which means lots of fish to look for!
|A steep volcanic rock face on the abyssal hill|
As we come to the end of the highly successful Autosub missions at the Porcupine Abyssal Plain and anticipate exciting new finds, we find that we are positively swimming in photos!