The Search for Didemnum: Day 5 (Now THAT'S More Like It)

Thursday, October 15, 2009

We got off to a great start!

Clear water, proper bottom type, and great lighting. Today is a day to find didemnum!

With the vehicle fully functional after the previous day's repairs, Seth and Mike began fishing in earnest.

We're no experts on identifying tunicates, but we had no problem finding spectacular examples of sea life amongst the volumes of images that Odyssey brought back.

This is a sunflower sea star.

A skate...

A flounder, doing a good job of blending in...

A tiny solaster (literally, a sun star)...

After taking a few thousand pictures, we decided to seek out more rocky bottomed waters by moving further east.

Our recovery was complicated by the rocking of the boat, but as a team we are getting used to handling the swinging vehicle.

(There were also some good pictures of the water column!)

Our second deployment went very smoothly.

Unfortunately, the water was far more turbid in our second area of operation. Sponges, anemones, and redfish dominated the images.

The sponges look like potatoes in these images.

Although beautiful to look at, anemones are not what we are after.

As the light faded, we made our last recovery for the week and prepared to head back.

We had pictures of too many starfish to count, in all shapes and sizes.

This one was hanging out inside a mussel shell. I can't tell if it's eating or just resting.

There were also quite a few crabs, hermit crabs, and sunflower sea stars.

Divide and Conquer

Wednesday, October 14, 2009

While Mike performed a miraculous teardown and rebuild of the vehicle on the deck of the Isabella & Ava,

Seth, Kyle, and I travelled back to Cambridge to put new oil into the thruster that had spent some time at the bottom of Gloucester harbor.

We met back up late that night.

The Search for Didemnum: Day 4 (One Good Mission, and Downhill From There)

Today we were accompanied by Rachel from the Northeast Consortium (NEC), the organization responsible for funding this trip.

We decided to survey near the outflow pipe from Boston because we figured that it would be warmer and more likely to sustain didemnum.

Deployment was rough. We immediately lost the vehicle behind the stern and had it pop up near the starboard bow. That can't be good.

However, everything seemed to have survived intact, so we started our day of testing. After a few false starts, we ran a survey mission to see if the warmer water from the outflow pipe would make a difference in our images.

It did...

Whether from the pipe or from the gale force winds during the previous night,

...the turbidity in the water made for terrible image quality.

This lobster trap was one of the few recognizable objects in all our photos.

Seth had no luck finding any fish, and the sea state didn't help.

Jellyfish, on the other hand were found in abundance








We decided to haul up the vehicle to try another location. It was especially difficult with the waves being higher than they were yesterday.

Odyssey swung quite a bit while we guided it to its cradle.

That's when things got worse.

"We're all done, guys" said Seth.


Besides the fact that the titanium thruster guard had been hit hard enough to crack one of its welds,

and the fact that the fiberglass CTD shroud had taken a beating,

it was the broken-off oil filling port in the thruster that got our attention.

We had been oeprating with slowly-leaking oil all day! Worse, we had no way to refill and re-close the hole; the show was over.

You can see the red paint that scraped off the bottom of the boat and onto our thruster.

There was no choice but to end the day early and attempt to do some emergency repairs.

Back to the lab!

On the way back to shore, John caught a bird that had found its way into the wheelhouse (miles from shore) and turned it loose outside.

Battery Recharge

Our battery continues to have a much tighter difference between its max and min cell voltages than we did before we replaced supercell #10.

This is what a healthy battery looks like.

The Search for Didemnum: Day 3 (Survey Patterns and Pictures)

Tuesday, October 13, 2009

Today we worked on our survey pattern behavior. We seem to have some troubles when heading due south.

Aside from that, the surveys look pretty good.

The images we are getting at 2m altitude are a little too pale. You can make out a scallop in this image, but not a lot of red channel is coming through.

We will have to fly lower to get good quality.

At 1.4 meters altitude, things are considerably better!

A crab.

A sea star.

A lobster.

A sunflower sea star, a sculpin, and a "regular" sea star.

We prepared to make the day's first recovery. Working as a team makes what would be an awkward (and somewhat hazardous) process go quite smoothly.

John (the first mate) is very good at coordinating the recovery process.

As the seas get rougher (from 25 kt gusts), deployment gets more "interesting". We try extra-hard to get the vehicle far from the boat before we let it go.

After putting Odyssey back in the water, we weren't able to accomplish much. There were some transient control issues in our way.

We did get a good sense of our minimum turning radius (at cruising speed) when we tried to hold a position.

All in all, we confirmed that the camera system is working reliably that our survey patterns actually look like survey patterns (even if dead reckoning is still a little behind).

Every trip to the surface has pictures filled with these jellyfish.