NOAA Teacher at Sea Beverly Owens Aboard NOAA Ship Henry B. Bigelow June 10 – 24, 2013
Mission: Deep-Sea Corals and Benthic Habitat: Ground-Truthing and Exploration in Deepwater Canyons off the Northeastern Coast of the U.S. Geographical Area: Western North Atlantic Date: June 18, 2013
Weather Data from the Bridge:
Air temperature: 13.50 oC (56.3 oF)
Wind Speed: 20.05 knots (23.07mph)
Science and Technology Log
Teacher at Sea Beverly Owens, and Dewey the Dragon at the Helm
On a research vessel such as NOAA Ship Henry B. Bigelow, does the ship support the science? Or are the ship’s activities separate from those of the Science Crew? I didn’t realize how much the Ship’s Crew and the Science Crew worked hand-in-hand until I toured the Bridge.
First off, the ship is what’s known as an FSV. What does FSV stand for? FSV stands for Fisheries Survey Vessel. The primary responsibility of the Henry B. Bigelow is to study and monitor the marine fisheries stocks throughout New England (the Northeastern section of the United States). There are many scientific instruments aboard the Henry B. Bigelow that allow crew members and visiting science teams to do this and other work.
The ship has multiple labs that can be used for many purposes. The acoustics lab has many computers and can be used for modeling data collected from multibeam sonar equipment. The chemistry lab is equipped with plentiful workspace, an eyewash, emergency shower, and fume hood. Our TowCam operations are being run from the dry lab. This space has nine computers displaying multiple data sets. We have occupied the counter space with an additional eight personal laptops; all used for different purposes such as examining TowCam images or inputting habitat data. The wet lab is where the collection sorting, and filtering take place. It is used during fisheries expeditions to process and examine groundfish. During our research expedition, the wet lab is used mostly for staging TowCam operations. We also process sediment and water samples that were collected from the seafloor. Sediment is collected using a vacuum-like apparatus called a slurp pump; water is collected in a Niskin bottle. The sediment is sieved and any animals are saved for later examination. Water samples are also filtered there, to remove particulate matter that will be used to determine the amount of food in the water column.
Walking around the ship, I noticed a psychrometer set, which is used to monitor relative humidity, or moisture content in the air. There is also a fluorometer, which measures light emitted from chlorophyll in photosynthetic organisms like algae or phytoplankton. The CTD system measures physical properties of the ocean water including conductivity/salinity, temperature, and depth. Additionally, the ship has a thermosalinograph (therm = heat, salin = salt, graph = write). Saltwater is taken into the ship and directed toward this instrument, which records the sea surface salinity and sea surface temperature.
The crew of the Henry B. Bigelow not only supports the research efforts of the science team but is also actively involved in conducting scientific research. Their instrumentation, knowledge, and team work enable them to protect and monitor the western North Atlantic waters and its living marine resources.
Personal Log
Dewey the Dragon is plotting the course.
Dewey the Dragon, all the way from Crest Middle School, enjoyed getting a tour of the Bridge. Dewey the Dragon learned how to steer the ship, read charts, and monitor activity using devices such as the alidade. Thanks to Ensigns Katie Doster and Aras Zygas for showing us around.
Did You Know?
Teacher at Sea, Beverly Owens, using the Alidade on the FSV Henry B. Bigelow
The alidade is a device that allows people on the ship to sight far away objects, such as land. The person on the ship spots three separate points on land uses these sighting to determine the location of the ship. Alidades can also be used as a tool when making and verifying maritime charts.
NOAA Teacher at Sea Beverly Owens Aboard NOAA Ship Henry B. Bigelow June 10 – 24, 2013
Mission: Deep-Sea Corals and Benthic Habitat: Ground-Truthing and Exploration in Deepwater Canyons off the Northeastern Coast of the U.S. Geographical Area: Western North Atlantic Date: June 23, 2013
Weather Data from the Bridge:
Air temperature: 17.23 oC (63.014 oF)
Wind Speed: 6 knots (6.90 mph)
Science and Technology Log:
We’ve seen amazing and beautiful animals living in these deep water canyons, many of which I did not recognize. During the progression of each tow I find myself asking the scientists around me, “What is that?” But that is what science is all about: being curious and trying to obtain the answers.
No matter how many hours I’ve sat on watch, or how many TowCam images I’ve looked at on the computer monitor, it’s still exciting to be one of the few people who get to see images directly from the ocean floor! It’s incredible that a large metal apparatus with a camera can send images and data thousands of meters through a tiny cable back to computers on the ship. As the pilots navigate TowCam through the water, images are sent back to the ship every 10 seconds.
Image highlights taken using TowCam during the Canyons CSI research expedition.
So what do we see in the images that are being sent back? I’ve gotten to see amazing things living more than a mile below the ocean. These include octopods and squids, skates, sea pens, anemones, delicate brittle stars, bivalves, and lush colorful coral gardens. All these organisms live on the bottom of the ocean in cold, dark water and under extreme amounts of pressure.
Morphology: The structure of a corallum.
How many different kinds of deep-sea corals are living at the bottom of the ocean? At least 71 species are known to occur off the northeastern coast of the U.S.; and new species are likely to be discovered. Many of the deep-sea corals look similar in color or structure. How do scientists tell them apart? They use taxonomic keys and DNA analysis to identify species. Dichotomous keys are a systematic way of identifying organisms by making a series of choices based on an organism’s characteristics. These keys are particularly useful if you don’t have instrumentation to conduct a DNA analysis.
Earlier this week, marine ecologist Dave Packer from NOAA’s National Marine Fisheries Service taught me how to use a dichotomous key for deep-sea corals. Corals are actually animals, even though many of them look plant-like in shape, so they belong in the Kingdom Animalia, the Phylum Cnidaria, and the Class Anthozoa. We began by discussing animals in the four Orders of deep-sea corals within the Anthozoa that are found off our northeastern coast: Scleractinia (stony corals), Antipatharia (black corals), Alcyonacea (soft corals and sea fans), and Pennatulacea (sea pens). Compare the corals shown below. You will notice that each group has a different style or appearance.
The Four Orders of Corals
Even though corals appear to be morphologically simple animals, they are highly detailed. Individual corals can be very small. Look at the image to the left to become familiar with some of the structures. Below are some additional features that may be found on different types of corals.
Some additional features that may be found in corals
Mr. Packer showed me a piece of coral that we would be “keying out.” By looking at the surface of it, we could tell it was a stony coral and belonged to the Order Scleractinia. Stony corals are usually very hard to the touch. Then, we examined its characteristics. Look at the picture to the right, and see if you can identify the characteristics that we examined on this coral:
Try your hand at Taxonomy
Is it solitary (grows alone) or is it colonial (grows with other coral polyps)?
Are the septa (fins sticking out at the top) smooth or rough?
Are the coral polyps only on one side, or scattered in a random pattern?
Is the coenosteum (portion of the skeleton between the polyps that looks like tree branches) porous or smooth?
Corals reproduce by “budding.” Do new corals bud inside an older coral (intratenticular) or are polyps added to the outside near older coral polyps?
Does it have 24 septa?
Check your answers below to see if you got these questions correct!
Drum roll, please… This coral is Solenosmilia. Try pronouncing that one! Going through an actual dichotomous key requires answering many more questions and making more choices. Coral polyps and structures can be so small that often a microscope is necessary to look at some parts. Sometimes corals may look very similar, so DNA testing is conducted to confirm the identification. Dichotomous keys can be used in identifying many other types of organisms as well, such as plants and fungi.
Want to try your hand at using a dichotomous key? Try this sweet activity using candy! Think about the characteristics of the candy pieces listed in the picture and key: Skittles, M & M’s, Gummy Bears, packaged Lemon Heads, unpackaged Lemon Heads, Dum Dum lollipops, Sugar Babies, Atomic Fireball, Mike and Ike’s, Tootsie Rolls, and Gobstoppers. What characteristics do they have in common? If you were going to sort them, how would you begin? We’re going to start with packaged versus unpackaged. Continue to follow along with the Candy Dichotomous Key until all the candy is sorted. How are the candy pieces similar? How do they differ? You have now used a dichotomous key to identify candy!
Candy Dichotomous Key (click to enlarge)Candy Dichotomous Key (click to enlarge)
Check your answers to the Coral identification:
Colonial
The septa are rough
The coral polyps appear to be randomly scattered
The coenosteum is smooth
These corals are intratenticular – notice how some appear to be budding off from one another.
No.
Beverly Owens, Teacher at Sea, with coral sample of Solenosmilia
Personal Log:
One of my favorite marine organisms is the starfish. We have seen many brittle stars during the course of our research expedition. There have been many large white brittle stars, and many tiny pink brittle stars that live symbiotically with certain corals.
Did You Know?
Corals are actually animals? They belong in the Kingdom Animalia. Corals can live colonially, with other coral animals, or can be solitary and develop alone.
(at anchor in Behm Canal at the mouth of Chickamin River)
Mission: Hydrographic survey
Geographical area of cruise: Southeast Alaska, including Chatham Strait and Behm Canal, with a Gulf of Alaska transit westward to Kodiak
Log date: June 16, 2013
Weather conditions: 26.04⁰C, scattered altocumulus clouds, 32.91% relative humidity, 1012.18 mb of atmospheric pressure, light variable winds (speed of less than 3 knots with a heading between 26⁰ and 51⁰)
A rare bit of breathing room in the passage of NOAA Ship Rainier through Wrangell Narrows
Explorer’s Log: Preparing for the transit through Wrangell Narrows
When watching a great concert, recital, or athletic event, we often forget the hours upon hours of preparation that were invested before the starting whistle or the rise of the curtain. History remembers and recites the first few moments of Neil Armstrong’s walk on the surface of Earth’s moon, but too often neglected from that history are the many years of research, discussion, calculation, prediction, and practice by thousands of people – including Armstrong – prior to that famous “one small step,” for without those advance preparations the brilliant moment likely never would have occurred.
Photos at the top of Everest belie the training, packing, mapping, and grueling climb that precede the snapshot. Last-minute buzzer beaters arise out of years of dribbling and shooting in empty gyms long after scheduled team workouts end. The revolutionary insights of Copernicus and Kepler were built upon hundreds of previous models and millions of recorded observations and related calculations. Great campaigns are waged on drawing boards long before they approach the battlefield.
This is the chart used during the navigational team meeting in preparation for Rainier’s approach to Wrangell Narrows.
Aboard NOAA Ship Rainier the culture of preparation is omnipresent. Posted on the door of my stateroom and carried in my pocket at all times is a billet card that delineates where I am to report and what task I am assigned in each of several emergency situations aboard ship. Within an hour of getting underway from the port of Juneau, the alarm sounded for a fire drill, and every person aboard reported smartly to his or her assigned station. Heads were accounted, gear was readied, and some crew members even donned full firefighting suits and deployed hoses and fans to address the fictional fire in the XO’s office. Because every person aboard knew his or her role in advance, the ship was prepared for the drill. And more importantly, because the entire ship participated actively in the drill, dealing with a genuine emergency, if necessary, will be more seamless and effective.
Then only ten minutes later, the alarm rang again. This time an abandon ship drill. As assigned, I retrieved my emergency gear and moved quickly to Muster Station 1 on the starboard bridge wing, where ACO Mark Van Waes explained in detail what would happen in the event of such an emergency.
As this sign above the fantail proudly displays, NOAA Ship Rainier values teamwork and puts safety first in all operations and missions.Careful navigation requires attention to details, like avoiding this small dock while leaving Juneau Port.
Of course, most of the preparatory work aboard Rainier is not about emergency situations, but rather is focused on readying for the work of navigating and operating the ship or the scientific missions of conducting surveys and samples, and that aspect of life aboard ship is non-stop. Everywhere around me, crew members and scientists are constantly working together, giving formal and informal trainings and lessons, offering one another ideas, insights, questions, and answers, unencumbered by the impediments of pride and arrogance that too often prevent achievement through growth. To the left of me, a young ensign is given room to make navigational decisions, while to my right two expert hydrographers consult available data and each other while they brainstorm about technical and theoretical issues on their own horizons.
The entrance to Wrangell Narrows is alongside the town of Petersburg, Alaska.Scientists from the survey team review data and documents while aboard the launch.
And the gathering of minds aboard Rainier is impressive. Today the hydrographic survey team assembled in the wardroom to talk about the upcoming week’s launches of smaller vessels to perform multi-beam sonar surveys and gather bed samples from the floor of Behm Canal. Under the guidance of FOO Mike Gonsalves, data were shared, schedules were outlined, and every member of the team – regardless of rank or role – was encouraged to share thoughts, concerns, and inquiries relevant to preparation for the task at hand, the ultimate task of this leg of Rainier’s mission. Like those other great events throughout history, here is yet another example of prior preparation preventing poor performance at the critical moment. And those were not the last conferences regarding the survey launches, either. A meeting regarding safety and other last-minute issues was held on the fantail before putting the launches out, and the various people aboard each small vessel constantly interacted to update and modify their ideas before executing their actions.
(Note: My next blog post will be about the scientific survey launches, so stay tuned!)
A panoramic view of the passage forward through Wrangell Narrows
The most impressive preparation during the past few days, though, was that of the navigational crew. After hours of work compiling past data and available current information and building itemized route plans for passage through the potentially-treacherous Wrangell Narrows, Ensign JC Clark led a large and comprehensive meeting to discuss every bit of the upcoming traverse. Utilizing charts, mathematics, weather forecasts, and expert opinions, the group of men and women in the boardroom created a plan of execution that considered everything from tides to local traffic, from channel depths to buoy patterns. Adjustments were made in an air of excitement tempered by the confidence of experience, preparation, and skill.
This device (called an alidade) on the starboard bridge wing is used for visual bearings.
And when the ship approached the town of Petersburg at the mouth of Wrangell, the preparation paid off. Turn after turn, command after command, the teamwork was superb, and the resulting passage was seamless. The ride was so smooth as the bridge maneuvered Rainier through the slalom in that deep and narrow fjord, that only the beautiful scenery itself was breathtaking.
During a brief opportunity to look away from the water, Chief Boatswain Jim Kruger worked on maintaining his expert knot-tying skills.
We tend to envision genuine explorers as being people who dare to travel beyond the horizon, choosing adventure over caution every time they set out. But the truth is that every great explorer, long before he lifts his foot for the first step of the travel, asks himself and his companions: Quo vadimus?
Where are we going?
Field Operations Officer Mike Gonsalves conducts one last survey team meeting on the fantail before the launches get underway.
The answer to that question might be a physical location, or it could just as easily be a direction. Up that mountain. Toward that little island. Around the bend. It could even be broad and metaphorical.
The ACO pulled out the binoculars to answer his own question of why that red buoy at the entrance to Wrangell Narrows was listing so much to the right. The tilt was because these sea lions were using the buoy to bask in the warm near-solstice sun.
But regardless of the short answer, the great explorer knows that the value of good preparation ultimately is the maximization of adventure can be maximized. Explorers may appear to disregard caution, but in fact, they have done the training, built the skills, plotted the course, and considered the likely obstacles in order to address that caution before getting underway.
But regardless of the short answer, the great explorer knows that the value of good preparation ultimately is the maximization of adventure can be maximized. Explorers may appear to disregard caution, but in fact, they have done the training, built the skills, plotted the course, and considered the likely obstacles in order to address that caution before getting underway.
ACO Van Waes shared with me a superb insight: The difference between a road map and a nautical chart is that a road map outlines a suggested path of travel, while the chart simply shows the traveler what things are out there. The hydrographic survey teams and supporting scientists who work for NOAA make nautical charts so that seagoing explorers can continue the great human endeavor of creating their own maps to turn curiosity into discovery, and I am very proud to spend these weeks working and learning among the people who keep that grand tradition going forward.
So prepare yourselves, practice your skills, plan a bit, and choose a direction or two. And then keep exploring, my friends.
Personal Log: Father’s Day
On the day before I left Florida I cropped my hair closely and stopped shaving my face (for the first time ever), in part to minimize the need for maintenance away from home, and also as a minor-league scientific experiment to compare rates of hair growth on the face and on the crown. After five days the chin, cheeks, and jawline seem to be winning the race. But the most interesting datum – as so often is the case in scientific tests – is a peripheral notation: When passing a reflective window this morning, I saw a familiar face framed by the short beard and small wrinkles at the edges of the sunglasses under the brim of my hat, but the face that I saw wasn’t my own. This third Sunday in June, thousands of miles from home, sort of pensively half-smiling at a fleeting thought that was blending with a pretty view of the treeline off starboard, I saw the face of my dad looking back at me. And my smile grew a bit softer and fuller when I caught glimpses of my sons in the reflection, too.
So happy Father’s Day to you three other Ulmer men who do so much to define this Ulmer boy. I’m proud of you, and I love you guys.
And on behalf of children everywhere, happy Father’s Day to the rest of you readers who have undertaken the great task of raising kids. Your work is important.
Did you know?
Underway through Gastineau Channel, outbound from Juneau
The ship’s propellers are called screws because essentially they spiral through the water to propel the boat forward by pulling water from in front and pushing it backward. NOAA Ship Rainier has two screws, one starboard (right) and one port (left), and they spin in opposite directions to make smoother and more efficient fluid dynamics. On this ship the screws constantly spin, but they are tilted differently to increase or decrease forward propulsion.
To increase forward vessel speed, the screws hang with a vertical profile so that the water moves horizontally backward from the boat, thus pushing the boat forward. To decrease forward vessel speed, the screws are tilted toward a more horizontal plane, decreasing the backward push of water, and consequently reducing the ship’s thrust force. It’s very much like holding your open, flat hand outside the window of a moving car and feeling the wind push it backward, upward, or downward, depending upon the angle of your palm relative to the car’s (and the wind’s) trajectory. Newton’s Third Law of Motion says that every action comes with an equal and opposite reaction, and so the more directly backward the water is pushed, the more directly forward (with the same amount of force) the ship is pushed in the opposite direction.
NOAA Teacher at Sea Eric Velarde Aboard R/V Hugh R. Sharp Wednesday, June 13, 2013 – Monday, June 24, 2013
Mission: Sea Scallop Survey Geographical Area: Cape May – Cape Hatteras Date: June 15, 2013
Weather Data from Bridge Latitude: 38°19.0778 N
Longitude: 74°15.9625 W
Atmospheric Pressure: 30.7in
Wind Speed: 11.5 Knots
Humidity: 70%
Air Temperature: 66.4°F
Surface Seawater Temperature: 66.2°F
Science & Technology Log
Deploying the Rosette to collect the first water sample for C.T.D. analysis & flying the HabCam V4 was the focus of work on June 15, 2013. The Rosette is deployed so that water samples can be collected to analyze the Conductivity, Temperature, and Depth (C.T.D.) of the seawater, providing data on the physical aspects of the Atlantic Sea Scallop’s (Placopecten magellanicus) habitat. The engineering team assumes responsibility of the Rosette, which is carefully lowered into the ocean through winch operation on the bridge. Once the Rosette has reached near the seafloor, it collects seawater and is then carefully retrieved through winch operation on the bridge. The seawater is then collected into an individual sampling bottle for analysis & calibration of the instrument.
Rosette C.T.D. Apparatus
Digital image rendering of the C.T.D. analysis allows for graphic visualization of the gathered oceanographic information, as well as calibration of the instrument. Analyzing the information demonstrates the two distinct layers of the ocean, separated by a relatively abrupt dividing boundary, which defines them. Atlantic Sea Scallops (Placopecten magellanicus) inhabit the seafloor in the lower layer of the ocean, whereas Plankton and Sea Scallop larvae can be found in the upper layer. Presentation of the C.T.D. readout gives accurate data of the Voltage (purple), Oxygen (blue), Temperature (red), and Salinity (green) levels.
C.T.D. Readout
As stated in my previous post, the HabCam V4 takes a tremendous amount of teamwork in order to operate at its maximum capacity. Correspondence with the engineering team is required to launch & retrieve the HabCam V4, the pilot must remain focused on ensuring that the HabCam V4 is close enough to the seafloor for maximum image quality, while at the same time being at a safe distance to prevent accidental collision, and the co-pilot is focused on incoming images & server traffic at a 2-monitor interface. All participating members of the crew must be attentive, communicative, and actively engaged in the contributing activities of other team members at all times.
HabCam V4 Co-Pilot Interface
The best way to describe piloting the HabCam V4 is to compare it to a video game, albeit one that has no “extra lives”. There is a pressure sensitive fiber optic cable feed & retrieval control lever that allows the pilot to either decrease or increase the depth of the HabCam V4. It is vital to maintain a safe distance while being in close enough range of the seafloor so that the incoming images are properly exposed and recognizable for the co-pilot. The optimum range is between 1.7 – 1.9 meters +/- 0.2 meters. Piloting the HabCam V4 during satisfactory weather is nearly effortless once having become acclimated to the 5-monitor interface and the control lever. Piloting the HabCam V4 during foul weather is quite difficult, requiring constant conscious concentration on all variables (seafloor depth, HabCam V4 depth, sonar readout, and fiber optic cable feed & retrieval) in order to prevent an accidental collision with the seafloor.
HabCam V4 Piloting
Co-piloting the HabCam V4 requires attention to the incoming images, as well as server traffic. Incoming images must be screened so that identified individual species can be time-stamped and tagged for analysis. Using software, the co-pilot can either tag observed species using digital identification markers, or manually input text to identify a particularly intriguing image that they wish to highlight for analysis. It is important to ensure that incoming images are being written to the server for digital archiving and future annotation. Digital data management, a scarcely celebrated 21st century character trait, is one of the many strengths of the crew aboard this vessel.
HabCamV4 Co-Piloting
Personal Log
Despite a few bouts of violent seasickness, I have been having the time of my life while aboard the R/V Hugh R Sharp. The crew possesses seemingly infinite amounts of sincerity, honesty, and intelligence. The continued operation of this wonderfully engineered human machine has occurred without error, and will continue to do so while under the watchful eyes of the leadership heads. Thus far my favorite aspect of this research experience has been co-piloting the HabCam V4. Having vast amounts of digital imagery stream before my observation makes me feel as though I am at home, screening digital images that I stumble upon for both scientific beauty & significance.
HabCam V4 Co-Piloting
In addition to the technological aspects of this experience, I have also found solace in the empathetic energy provided by the ship’s captain, Jimmy Warrington. His humor, experience, and leadership create an ideal teaching & learning environment. While many may dread the monotonous nature of a safety briefing, the one provided by the Captain was both engaging and informative. Following safety briefing, newcomers to the R/V Hugh R. Sharp are required to don a safety immersion suit in less than 60 seconds. The safety immersion suit is more commonly referred as a “Gumby Suit”. The suit is quite impressive, being both insulating and buoyant. It possesses a safety whistle, flashlight, interpersonal locking hooks, and even an inflatable pillow. It is reassuring to know that above all else, safety is the primary focus of the leadership on this vessel.
Safety Immersion Suit or “Gumby Suit”
Being on duty from Midnight-Noon causes me to miss the opportunity to observe sunsets at sea on most nights, but I have been able to experience a few and they are simply the most breathtaking sunsets that I have ever seen. Watching the night divide the day is both awe-inspiring and thought provoking. Despite my colorblindness, I feel that I am still capable of absorbing all of the electromagnetic energy that the sun provides during this hour of magic.
Sunset Storm
Dredge tows will be the focus of upcoming days, and is something that I am looking forward to. As a biologist, I find all living organisms infinitely beautiful and stimulating. I cannot wait.
-Mr. V
Did You Know?
The Atlantic Sea Scallop Fishery is the largest & most valuable scallop fishery on planet Earth, valued at $580,000,000 in 2011.
I’ve donned an immersion suit, also known as a survival suit. One of the first things I did when I came aboard was to locate this suit and my life vest, two pieces of equipment that save lives. In the event we had to abandon ship, the survival suit would keep me both warm and afloat until rescue. During our evacuation drill we needed to unpack and get into the suit, and be completely zipped up in 60 seconds or less. Getting into the suit was much easier after I took my shoes off, as the soles caught on the fabric of the suit. The suit is made of neoprene, which was invented in 1930. SCUBA wetsuits are also made of neoprene, and even some laptop and tablet cases.
In an earlier blog I talked about the CTD being used to calibrate the sonar aboard the Oscar Dyson, but not all technologies on the Dyson are as high tech as the CTD and sonar equipment. In fact you can build a weather station at home that is similar to some of the equipment used by the Dyson’s crew. Below is a picture of a hygrometer. There are actually two hygrometers aboard, one is located on each side of the bridge. Hygrometers are used to measure relative humidity (how much moisture is in the air). Also pictured is the wind bird which shows the direction the wind is moving. The propeller was actually turning rapidly when the picture was taken. The camera was able to “stop” the action. The wind bird is mounted atop the jack staff, high above the bow.
Hygrometers are weather instruments used to measure relative humidity.
The following link shows you how to build six instruments for monitoring the weather.
If you checked out the above link, how many snow days to you think the kids in North Dakota had?
Did you check out ship tracker? If you did, the screen shot below will look familiar. The blue lines in the water display the Dyson’scourse. Each segment of the course is called a transect. Transects are numbered, enabling scientists to easily reference a location.
Oscar Dyson‘s course as of 6 18 13
Are you wondering why we have traveled in rectangular patterns? The scientists establish this course for a several reasons:
Transects run perpendicular to the coast line, covering a wide range of bathymetry over the shortest distance.
Regularly spaced transects (as opposed to randomly spaced or scattered) are correlated with historical data, and are the best way to describe the distribution of pollock.
The combination of transects collects sufficient data to allow scientists to estimate the overall size of the pollock population with a high degree of certainty.
Does anyone have an idea about the meaning of “bathymetry” and a “leg”? No, in this case a leg is not something you stand on. Bathymetry is the shape and depth of the ocean floor, and a bathymetry contour line on a chart connects points of equal depth (like a topographic map). A leg, in this context, is a segment of the overall distance covered in the survey.
The information collected during this year’s survey helps determine the number of pollock that can be caught in next year’s fishing season.
Here is the ship tracker link, you can check out the Dyson’s course and other NOAA ships as well.
I want to revisit the sonar of Mystery Mix One. In my last blog I talked about what was happening near the surface of the ocean. This time I want to focus beneath the sea floor.
Graphic provided by NOAA
Look beneath the red, yellow, and green bands, depicting the sea floor, at the blue color, notice how the density of color changes over time. The density of the color tells scientists about the composition of the sea bed. The denser the color, the denser or harder the seafloor is likely to be; probably, the places with the dark, dense color are rocky areas, which attract the fish schools seen in the water above.
Looking at this graph reminds me of an experiment that my husband worked on, when he worked for Charles Stark Draper Labs, in Boston, MA. He worked on a Gravity Gradiometer that was sent to the moon on Apollo 17. The gradiometer measured the changes in gravity. The changes in gravitational strength give scientists information about what lays beneath the moon surface, like the sonar provides information about the sea bed. The Gravity Gradiometer was a very specialized version of equipment that is commonly used in prospecting for oil on Earth. I am sharing this story because, in class, one of our foci is to take what we know and apply the knowledge to a new scenario. Next question: Where will what we know now, take us in the future?
