Northeast U.S. Canyons Expedition




Ask an Explorer


 

Question from:  Ed, Florida
Do either of the remotely operated vehilces (ROVs) have hydrophones to hear the environment or are the robots so noisy it would not be worthwhile?

Answer from: Brian Bingham, ROV Operations Manager, Professor at University of Hawaii

The current ROV, Deep Discoverer, does not yet have a hydrophone on board. This is the first exploration expedition for the new ROV, so we are excited that we have the major operational systems (thrusters, telemetry, etc.) running so well - 12 straight dives so far!

The NOAA Office of Ocean Exploration and Research is working to define a suite of sensors to support exploration in future expeditions, and a hydrophone may be one of the standard sensors since acoustics can be used to characterize the ocean environment.

We have had hydrophones on other ROVs for both scientific and engineering purposes. The platform can be noisy, especially when running thrusters and hydraulics, but it can also be quiet when those systems are secured.

One system you might be interested in is the Aloha Cabled Observatory in the Pacific. It has real-time streaming audio from the seafloor at 4,000 meters depth. You may find marine mammal migration, surface ships, and earthquake evidence in the data!

 


 

Question from:  Ed, Florida
Zooxanthellae can’t photosynthesize at depth. How do the corals survive without them and does any of the knowledge gained here help us understand bleaching event survival? Do the cup corals and bamboo have chemosynthetic bacteria that provide the function of the algae?

Answer from:  Andrea Quattrini, Co-Science Team Lead, PhD Student, Temple University
Great question. The corals that we see in the deep-sea are azooxanthellate corals, meaning they do not contain the symbiotic algae (Symbiodinim) as those corals in shallow depths. That means, most deep-sea corals have to feed on particulate matter and plankton in the water column. Size of prey that is able to be captured by a coral polyp depends upon the size of the polyp. Most corals therefore live in areas of strong currents in order to capture a high amount of food from the water column.

All of the corals in the deep-sea have associated “microbiomes,” a suite of various microorganisms including bacteria, and maybe even fungi and viruses. However, to our knowledge, there is no chemosynthetic bacteria living in the tissue, as corals do depend upon photosynthetic energy produced from surface waters above. Researching the microbiomes of corals is a relatively new and burgeoning field, and an exciting avenue for future research.


 

Question from:  Ed, Florida
With all the marine snow falling down, why isn’t EVERYTHING covered? Does anything eat it? Looking at overhang colonization, there seems to be an advantage to staying out of the direct snow. When it does pile up, like on those blocky rocks. The angle of repose seems shallow. Is that due to the propensity to resuspend, the rocks are actually at a steeper angle, or an ooze like flow to accumulations of the snow, or some combination?

Answer from:  Andrea Quattrini, Co-Science Team Lead, PhD Student, Temple University
Marine snow is mostly organic detritus that is nutrient rich, and a primary source of energy in the deep-sea. Many organisms do capture particles from the water column by filter feeding, and as the particulate matter falls to the bottom, it is utilized by microorganisms and other meio and macrofauna that live in and on the sediment. In areas of high currents, this “marine snow” will be swept to certain areas of the seafloor until it is deposited.

The fact that organisms are growing under ledges is likely a combination of a few geological processes on the seafloor. The corals may be oriented in a way to maximize extending their polyps in strong currents to capture food, while not being smothered by debris raining from the rocks above. High sedimentation can often smother corals. As you can see in some areas that we have dived, a veneer of sediment covered the rock faces.


 

Question from:  Aleksis, Finland
You seem to gather a lot of information with technical equipment (data, images, video). How about traditional note taking? Is there a need for taking notes with either pen and paper, or perhaps a laptop? If yes, what kind of notes?

Answer from:  Brendan Roark, Assistant Professor, Texas A&M University
Yes, we take other types of notes. For example I take notes on my laptop of our position, what the bottom looks like, what organisms are present, technical problems and other important events like the first sighting of a coral during the dive or cruise. We use these notes to write our dive summaries. I also take pen and paper notes on a printed version of our dive map to help me keep track of where we have been. There is also the IM chat room that logs all of the notes all the scientists make. We use all these notes and data, both the data, images, video and transitional notes to do our daily dive reports and web summaries. We also have pre and post dive meetings via conference phone to discuss and plan past and future dives, so that is also a more traditional form of communication.


 

Question from:  C.K. via email
What is the distance of the laser beams that are used to scale size?

Answer from:  Kasey Cantwell, Web Coordinator, NOAA Office of Ocean Exploration and Research
The distance between the laser beams is 10 cm, or just under 4 inches.


 

Question from:  Ed, Florida
Do you ever do stereo pair video capture? You almost have it now, but video stream2 is at an odd angle and streaming with a second or two delay. It would be amazing to see the video 3D live down there.

Answer from:  LTJG Brian Kennedy, NOAA Office of Ocean Exploration and Research
No, we have not done any 3D camera work however I believe a couple other groups are looking into make a 3D underwater camera. For today feed one is our main HD camera which is located lower on the ROV. Stream 2 has the view from a Mini HD camera mounted near the top of the ROV. We are using the mini HD for a wide angle view of the area while the main HD does the zoom work.


 

Question from:  Ed, Florida
Some of the chat mentioned that the holes in the rock may be a biological weathering process rather than fossil voids or vugs weathered out. Do you know if that is the case?

Answer from:  Jason D. Chaytor, Ph.D, U.S. Geological Survey, USGS Woods Hole Coastal and Marine Science Center
Several observations from the video and information about the types of rocks encountered during the dive lead us to the conclusion that the holes are the result of biological activity rather than relict voids or weathered out vugs. First the composition of the rocks: Based on work carried out of 40 or so years, rocks at this stratigraphic level likely contain a significant amount of carbonate mixed with clay, silt and sand derived from land. The carbonate is usually in the form of a cement which binds the other grains together. This cement actually makes the rocks very strong and resistant to physical erosion (this can be seen in the ability of the rock to form large overhangs), say from bottom currents, but susceptible to chemical (dissolution by acidic waters) and biological erosion. One of the important observations which points to bio-erosion is the difference between fresh surfaces of these rocks (perhaps created by a small slope failure) and the more abundant rock covered by holes. The fresh surfaces are free of any trace of holes or noticeable inclusions (such as vugs, embedded rocks, or other cavity filling materials). The question now is, what animal actually created the holes? Right now, we don't have an answer for that.


 

Question from:  Ed, Florida
I noticed several repeated hollows in the rock of relatively the same size and shape. I’m wondering if they would be due to a tunneling organism or a buried and lithified set of organisms?

Answer from:  Jason D. Chaytor, Ph.D, U.S. Geological Survey, USGS Woods Hole Coastal and Marine Science Center
I will assume you are referring to some of the larger hollows, sometimes almost big enough to stick a football in. We believe that they are burrows possibly being created, but definitely being expanded (you can often see fresh sediment piled up outside the hollows suggesting active maintenance or expansion) and utilized for shelter by one or more type of fauna. It would not be surprising if the locations of the hollows are a result of weaknesses in the rock, which are then exploited by the animals to make the process of developing the burrow easier. We do often see these along subtle changes in rock type and along fractures, especially at the base of some of the cliffs. As with the smaller holes, we still have a lot to learn about the interaction of geology and biology in the deep sea.


 

Question from:  Ed, Florida
Can you tell me what the red-bodied krill are?

Answer from:  Andrea Quattrini, Co-Science Team Lead, PhD Student, Temple University
They are Euphausids.


 

Question from:  Ed, Florida
Is there a known advantage to the impressively long antennae on the shrimp and krill observed today? Are they useful for picking up longer wave vibrations?

Answer from:  Andrea Quattrini, Co-Science Team Lead, PhD Student, Temple University; and Brendan Roark, Assistant Professor, Texas A&M University
The long antennae are typically used for tactile and chemo sensory. The shrimp use them for sensing their environment - it’s very dark in the ocean depths! They may also use them to encounter prey at longer distances, which would also be useful in the deep ocean.

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