underwater robotics

Listening for History: Exploring Thunder Bay National Marine Sanctuary with Sound

How do you find a shipwreck in a 23,000-square-mile lake? For researchers, it can be like finding a needle in a haystack. 

This spring, researchers in Thunder Bay National Marine Sanctuary undertook the second phase of a research expedition to find lost shipwrecks within sanctuary waters in Lake Huron. From May 15 through 26, they used acoustics to explore deep water areas off Presque Isle.

University of Delaware researchers monitor incoming survey data from R/V Laurentian’s science lab. Photo: NOAA

Unlike on land, where features can be documented with aerial imagery or satellites equipped with cameras, visual survey isn’t practical underwater. In some cases the water is too murky, or turbid, to take photographs. At deeper depths there simply isn’t any ambient light. A camera, therefore, would only see darkness unless an array of lights was lowered down with it to illuminate the area.

Sound, however, is astonishingly efficient underwater. The density of water, both freshwater and saltwater, allows sound waves to travel great distances. When these waves encounter an object, they bounce off and in some cases reflect back in the direction of their original travel. In fact, by knowing the speed of sound through water, researchers can calculate how far away an object is. If the object being mapped is the lake floor, in this case the bottom of Lake Huron, the distance to the bottom, or water depth, can be determined by the time delay between a sound wave emitted at the surface and its travel to the lake floor and return back to the source at the surface.

The behavior of sound in water is so reliable that hydrographers can make detailed maps of the seafloor, accurate to within inches. Archaeologists can also use this technology to locate undiscovered shipwrecks. Where the lake bottom is flat and even, a historical shipwreck will appear as a large “anomaly” in the sonar data, a feature that sits upright off the bottom in stark contrast to the surrounding natural features. Once located, researchers can return with additional tools, such as underwater robots or divers, to further document a potential discovery.

University of Delaware sonar technicians Kenny Haulsee and Peter Barron route cables from the echosounder (yellow device in foreground) along a pole mount used to lower and secure the echosounder along the side of the vessel. The team installed and tested the entire sonar system while dockside to ensure proper operation before getting underway within the survey area. Photo: NOAA

Using sound to reveal lost shipwrecks

When researchers are first characterizing the lakebed or seafloor, we use a sonar system that can see a wide strip of the bottom at once. By running a pre-planned grid of overlapping passes – a technique referred to as “mowing the lawn” for the pattern it creates – researchers end up with a complete map of a given area. However, this wide-scanning sonar results in a less detailed image, or lower-resolution one, than a more focused sonar would reveal.

As a result, a dual-phase approach is often needed. That’s where the multiple phases of the Thunder Bay shipwreck expedition come in. In Phase II, completed in May, researchers used a wide-reaching sonar to scan large portions of the lake floor. By surveying large areas as quickly as possible, previously unexplored areas can be covered and new discoveries made.

Once surveyed, archaeologists will examine the data and tag anomalies against the surrounding lake floor. These may turn out to be lost shipwrecks. Then, in June’s Phase III, researchers will return to those targets with more detailed documentation methods.

University of Delaware sonar technician Peter Barron prepares to lower a device that will measure the speed of sound throughout the entire water column. These sound velocity profiles were collected once every four hours during the entire survey. Photo: NOAA

Presque Isle: The intersection of a maritime highway

The waters off Presque Isle in central Lake Huron form a sort of crossroads for the area’s shipping lanes. The lanes for vessels traveling up and down the lakes, whether to and from the Straits of Mackinaw or the Soo Locks, all converge within about 10 miles of the Presque Isle lighthouse. Within this area, many ships have collided and sunk during periods of bad weather or limited visibility. Dozens of known shipwrecks are spread across the lake floor off Presque Isle, and many more have yet to be found.

Many ships have met their end off the shores of Presque Isle in Lake Huron. Photo: David J. Ruck/NOAA

For this reason, researchers from Thunder Bay National Marine Sanctuary selected a large, 100 square mile area off Presque Isle for a wide-area exploratory survey. Partnering with the University of Delaware and using a research vessel from the NOAA’s Great Lakes Environmental Research Lab (GLERL), they conducted a two-week survey mission in May to search for undiscovered shipwrecks.

With a six-person survey crew, the mission involved 24-hour continuous operations for six days. Breaking into two-person watches, members of the team would spend four hours running the survey gear, followed by eight hours off, then another four hours on within a given 24-hour time period. That way, a team of researchers was constantly operating the sonar. The teams logged and organized data files, selected and managed survey scan lines, and communicated with the research vessel’s crew regarding navigation, survey speed, and general movement throughout the survey area.

A preliminary side scan sonar mosaic composed of 24 individual survey lines. Across the lake’s bottom, numerous features can be seen, including geological formations and variable bottom types. Image: University of Delaware.

As sonar data was logged, researchers also took additional measurements of the speed of sound through water. Approximately every four hours, a device was sent to the bottom of the lake. As it traveled, it measured the speed of sound and produced a sound velocity profile. By accurately measuring how fast sound was moving through the water, the researchers could accurately determine the distance to the bottom.

As six days passed, over 400GB of sonar data was logged and 100 square miles of area were covered. Now, researchers have to process all of the data and review it for anomalous objects that may turn out to be new shipwreck discoveries. During Phase III operations, these targets will be investigated with high-resolution sonar onboard an autonomous underwater vehicle operated by Michigan Technological University. Stay tuned for a recap of that leg of the expedition in a few weeks!

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Vortices are a ubiquitous part of life, whether they’re draining down your bathtub or propelling underwater robots. In the latest video from the Lib Lab project, you can learn about how vortex rings form, what makes them last so long, and even make a vortex generator of your own. I can personally attest that vortex cannons are good for hours of entertainment, no matter your age. They’re even more fun with friends, as the Oregon State drumline demonstrates in the video. Want even more vortex fun? Check out leapfrogging vorticesvortex rings colliding head-on, and a giant 3 meter wide vortex cannon in action. (Video and image credit: Lib Lab)

cyberbeastswordwolfe  asked:

Hello! I just graduated from High School and I'm looking to get a degree in Marine Biology. What sort of Math, Science, History, and English classes do you recommend I take in order to achieve the degree?

Hi there and congratulations! You are in for a great experience!! The classes you’ll take will be determined largely by the school you got to and the programs available, that being said there are certain things you can focus on when choosing classes.

If you are starting at a school that does not have a marine science program you may have to get creative. Always look through the electives, you never know when you’ll find a professor with a niche interest that couldn’t be part of the curriculum and made an elective class just becasue they wanted to.

Math: Marine Biology is not a math heavy field, that being said I had to take math classes up to calculus and a bio statistics class. Stats is going to be important regardless of what type of biology you are in. It is preferable that you take a stats class based in bio, rather than something like business.

History: This one is a little tricky, people have been connected to the oceans since the beginning of recorded history. Ultimately this one is going to boil down to personal preference. I’m personally a fan ancient history and I took a History of Paris class, not becasue it had anything to do with marine bio, but becasue I thought it sounded interesting.

English: Have fun with this one! If you want to look for classes that focus on literature surrounding the oceans and beaches (there are quite a few books out there for that) then do it! But if you want to take something like Shakespearean Lit, or detective fiction, or creative writing do that. Remember that college is not just about pursuing your intended career, but also about broadening your horizons.

Language: I know you didn’t ask about this one but I’m including it anyway. It is never a bad thing to learn another language and it will make you more marketable if you do. However, it’s not necessary, I actually have never been able to learn another spoken language, but I have been able to learn a little bit of American Sign Language and it has helped me from time to time.

Science: Saved this for last! Obviously you want to take as many marine bio, marine, science, and oceanography classes as you possibly can. Anything having to do with marine life (animal and plant) will help you. Some of my classes included intro to marine bio, tropical marine bio, ichthyology, fisheries management, and underwater robotics. However, you are also going to need a strong Biology background. My school had cells & molecules and biodiversity & evolution classes that were required. I also had to take a chem and organic chem classes. As well as the first two levels of physics for life sciences.

Ultimately it boils down to a few things

1) What does your school require you to take in order to get your degree. This is huge and is going to determine most of the classes you have to take, although they usually have a few options/alternatives.

2) What aspects are you more interested in/where do your strengths lie? (fish, inverts, marine mammals, seaweeds, oceanography, etc.)

3) Which classes will give you the knowledge and skills you want/need? I love classes that involve field work because you get to focus on the practical application. It also gives you great resume material (file under “course experience”).

Well I hope this helps you! And don’t forget to have fun! College is what you make of it. I promise you will get out what you put in.

Simon Jarrett and K8/UH8 from the game SOMA, by Frictional Games c:

Hhhh I’ve wanted to draw some SOMA fan-art for… Idk when this game came out. And now I finally did it~

And man I’m happy to finally draw something I’m actually quite proud of! Feels weird but good.

I still need a bit more simple style for drawing humanoids, though…

  • Professor Moorhouse: Earth legends are such dry, dusty affairs. And always fiction.
  • The Doctor: I wonder if I should tell him about when I met Robin Hood
  • The Doctor: or the Loch Ness Monster
  • The Doctor: or when I went to Atlantis
  • The Doctor: or the other time I went to Atlantis
  • The Doctor: or that time I met an Egyptian god
  • The Doctor: or when Rose chucked Satan into space
  • The Doctor: or the vampires
  • The Doctor: or the other vampires
  • The Doctor: or the other other vampires
  • The Doctor: or the werewolf
  • The Doctor: or when Merlin turned out to be me
  • The Doctor: *smiles*
Prophet City: Part Eight

A Dean x Reader / Superhero!Au

Master List

A/N: I just want to start off by apologizing for taking so long. I worked sooo hard on this for such a long time so I truly hope you guys like it. Please let me know what you think. ily <3

Word Count: 4,027

Other Characters: Charlie

Warnings:
- language.
- mild violence.
- talk of death.
- twinge of angst.

Tags: (at the end)

*gifs are not mine. 

Doing as you were told, you froze in place, scared to even move an inch. Charlie’s voice was gone from the intercom, replaced with a soft buzzing that echoed off the bare walls of your prison. Suddenly, it was so quiet you could hear a pin drop; the only sound you heard was your own heart, hammering in your chest. 

Seconds ticked by and nothing happened, your body beginning to ache from lack of movement. When sudden muffled screams and slams could be heard outside the door, you thought you were hallucinating. Still, you didn’t move, afraid that one small muscle twitch would ruin what Dean and Charlie had planned.

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