NOAA Teacher at Sea Louise Todd Aboard NOAA Ship Oregon II September 13 – 29, 2013
Mission: Shark and Red Snapper Bottom Longline Survey Geographical Area of Cruise: Gulf of Mexico Date: September 19, 2013
Weather Data from the Bridge: Barometric Pressure: 1017.17mb
Sea Temperature: 28.8˚C
Air Temperature: 27˚C
Wind speed: 18.05 knots
Science and Technology Log:
Those of you following our progress on the NOAA Ship Tracker might have noticed some interesting movements of the ship. We had some rough weather that forced us to skip a station, and the current by the mouth of the Mississippi River also forced us to skip a station. The safety of everyone on board comes first so if the seas are too rough or the weather is bad we will skip a scheduled station and move to the next one. Now we are off the coast of Florida and hope we can get some good fishing done!
This survey is being done using longlines. Longlines are exactly as their name describes, long stretches of line with lots of hooks on them. The line we are using is 6,000 feet long, the length of one nautical mile. From that long line, there are 100 shorter lines called gangions hanging down with hooks on the end. Each gangion is 12 feet long.
Gangions in the barrel
When we arrive at a sampling station, everyone on our shift helps to set the line. In order to set the line, we have to bait each one of the hooks with mackerel.
Baited gangions ready to go
Once the hooks are baited, we wait for the Officer of the Deck (OOD), driving the ship from the bridge, to let us know that we are in position at the station and ready to start setting the line. The first item deployed is a high flyer to announce the position of our line to other boats and to help us keep track of our line.
High flyers ready to be deployed
This is a bottom longline survey so after the high flyer is deployed, the first weight is deployed to help pull the line to the bottom of the ocean just above the seabed. After the first weight is deployed, it is time to put out the first 50 hooks. This is typically a three person job. One person slings the bait by pulling the gangion from the barrel and getting ready to pass it to the crew member. Another person adds a number tag to the gangion so each hook has its own number.
Number clips are attached to each gangion
A member of the deck crew attaches each gangion to the main line and sends it over the side into the water. The gangions are placed 60 feet apart. The crew members are able to space them out just by sight! The bridge announces every tenth of a mile over the radio so they are able to double check themselves as they set the line. Another weight is deployed after the first 50 hooks. A final weight is placed after the last hook. The end of the line is marked with another high flyer. Once the line has been set, we scrub the gangion barrels and the deck. The line stays in the water for one hour.
Once the line has soaked for one hour, the fun begins! Haul back is definitely my favorite part! Sometimes it can be disappointing, like last night when there was absolutely nothing on the line. Other times we are kept busy trying to work up everything on the line. When the line is set and brought back in, everything is kept track of on a computer. The computer allows us to record the time and exact location that every part of the line was deployed or retrieved. The touchscreen makes it easy to record the data on the computer.
Computer ready to document what is on each hook
Personal Log:
It is nice to be doing some fishing! There have been some long distances in between our stations so my shift has not gotten the opportunity to set the line as much as we would like. I’m hopeful that the weather holds out for us so we can get a few stations in on our shift today. Being able to see these sharks up close has been amazing. I am enjoying working with the people on my shift and learning from each one of them. Before we haul back the line, I ask everyone what their guess is for number of fish on the line. My number has been 45 the past few haul backs and I’ve been wrong every time! Christine was exactly right on one of our last haul backs when she guessed two. I know I’ll be right one of these stations. It is hard to get pictures of what comes up on the line because we get so busy processing everything. I’m going to try to get more pictures of our next stations.
The views out in the Gulf are gorgeous. I never get tired of them!
Can you see the moon?Sunset over the Gulf
Did You Know?
When we arrive at a sampling station, the officer on watch must be aware of other ships and rigs in the area. At times the bridge watchstander will make the decision to adjust the location of our sampling station based on large ships or rigs in the area.
Rigs and other ships in the area of a sampling station can force us to move the station
NOAA Teacher at Sea John Clark Aboard NOAA Ship Henry B. Bigelow September 23 – October 4, 2013
Mission: Autumn Bottom Trawl Survey Geographical Area of Cruise: North Atlantic Date: September 18, 2013
Introduction
Thank you for reading about my adventures at sea. My name is John Clark and I’m entering my 7th year teaching science at Deltona High School in Deltona, Florida. Our community is just off I-4 between Orlando and Daytona Beach. Teaching is my second career, after working in the telecommunications field, and I love getting students excited about science. I’ve even earned a few awards for being successful at it. I’m married to the love of my life, Jill, who is also a teacher. In our lives are three grown children and seven grandchildren. With great blessings, I share that they are all healthy, happy, and live close enough for us to see them regularly. At home we have replaced the kids with two cats and a dog.
My wife Jill with grandson RionJills husband – me, John ClarkSabi dog in the pool with granddaughter Morgan
In a few days, anticipation will be replaced by action as I board a plane headed for my NOAA Teacher at Sea experience I’ve waited for all summer to begin. I’ll be sailing aboard NOAA Ship Henry B. Bigelow, a ship specially built for NOAA to carry out the type of fisheries research I’ll be taking part in. I’ll be working side by side with experienced scientists who not only are knowledgeable in how to do the research conducted on board but also have the skill to share their knowledge with volunteers like me who have limited background in the science behind the work. It is the experience of a lifetime that I hope will energize my students about studying science as we carry out lesson plans developed from the experience and I share with them the stories of my time at sea. I’m sure a giant boat-eating squid will be in there somewhere.
NOAA Ship Henry B. Bigelow
Officially, I’m taking part in 2013 Autumn Bottom Trawl Survey conducted by the Ecosystems Survey Branch of the NOAA Fisheries Service. That’s a long fancy way of saying that the ship is going to drag a net for a short period of time near the bottom of the ocean and then collect data on the types of fish we catch as well as the environment they live in. Affectionately called a “critter cruise”, I now join a long line of Teacher at Sea alumni who have taken part in the biannual surveys of North Atlantic marine life. And there are a lot of critters to learn to identify as I’m finding out from watching the CD I was sent to be better prepared to support the research team. There are two types of Dogfish which look suspiciously like little sharks, flounders that are left eyed or right eyed depending on which side they decided to leave up, and squid distinguished by the length of a pair of fins down the side of the body. All you do is hold them upright, tentacles hanging toward the ground, and take a look. And don’t forget the large lump fish which is described as have the texture of a dog’s chew toy. Whatever the species, the role of the research volunteer is to sort them out and then collect data for the scientists to study.
Scientists sorting a catch aboard the Bigelow
What can be overlooked in the preparation is the part about how to handle fish. I do not like to touch fish so I will be facing my fears even while wearing gloves. And I really don’t like it when they flop around. I envision I’ll be the one with the hand in the wrong place when the shark twists around to see who is holding its tail or, at a minimum, squeeze too hard on the species that will poke you with a poison spine if you upset them. Other good advice I’ve learned from the CD is that there is a 100% recovery from seasickness and if the seas get rough, wedge yourself into your bunk with your life vest so you don’t roll around and fall out. My two year old granddaughter, Ireland, was watching the video with me while I studied and all she could say was “Oh my.”
NOAA Teacher at Sea Britta Culbertson Aboard NOAA Ship Oscar Dyson September 4-19, 2013
Mission: Juvenile Walleye Pollock and Forage Fish Survey Geographical Area of Cruise: Gulf of Alaska Date: Saturday, September 15th, 2013
Weather Data from the Bridge
Wind Speed: 11kts
Air Temperature: 12.2 degrees C
Relative Humidity: 87%
Barometric Pressure: 1010.7 mb
Latitude: 59 degrees 26.51″ N Longitude: 149 degrees 47.53″ W
Science and Technology Log
Finally, as we near the end of the cruise, I’m ready to write about one of the major parts of the survey we are doing. Until now, I’ve been trying to take it all in and learn about the science behind our surveys and observe the variety of organisms that we have been catching. In my last few entries, I explained the bongo net tow that we do at each station. Immediately after we finish pulling in the bongo nets and preparing the samples, the boat repositions on the station and we begin a tow using an anchovy net. It gets its name from the size of fish it is intended to capture, but it is not limited to catching anchovies and as you will see in the entry below, we catch much more than fish.
Why are we collecting juvenile pollock?
We are interested in measuring the abundance of juvenile pollock off of East Kodiak Island and in the Semidi Bank vicinity. We are not only focusing on the walleye pollock, we are also interested in the community structure and biomass of organisms that live with the pollock. Other species that we are measuring include: capelin, eulachon, Pacific cod, arrowtooth flounder, sablefish, and rockfish. As I described in the bongo entries, we catch zooplankton because those are prey for the juvenile pollock.
On the top is an age 2+ pollock, below that an age 1 pollock, and then below that is an age zero pollock. (Photo credit: John Eiler)
The Gulf of Alaska juvenile walleye pollock study used to be conducted every year, using the same survey grid. Now the Gulf of Alaska survey is conducted every other year with the Bering Sea surveyed in alternating years. That way, scientists can understand how abundant the fish are and where they are located within the grid or study area. With the data being collected every year (or every other year), scientists can establish a time series and are able to track changes in the population from year to year. The number of age 0 pollock that survive the winter ( to become age 1) are a good indicator of how many fish will be available for commercial fisheries. NOAA’s National Marine Fisheries Service (NMFS) will provide this data to the fisheries industry so that fishermen can predict how many fish will be available in years to come. The abundance of age one pollock is a good estimate of fish that will survive and be available to be caught by fishermen later, when they reach age 3 and beyond, and can be legally fished.
The other part of our study concerns how the community as a whole responds to changes in the ecosystem (from climate, fishing, etc.). That is why we also measure and record the zooplankton, jellyfish, shrimp, squids, and other fish that we catch.
How does it work?
The anchovy net (this particular design is also called a Stauffer trawl) is pretty small compared to those that are used by commercial fishermen. The mesh is 5 millimeters compared to the 500 micrometer mesh that we used for the bongo. The smallest organisms we get in the anchovy net are typically krill.
A picture of a generic trawling net. It’s very similar to the anchovy net that we are using.
Typically, we don’t catch large fish in the net, but there have been some exceptions. You might wonder why larger fish do not get caught in the net. It’s because the mesh is smaller and it’s towed through the water very slowly. Fish have a lateral line system where they can feel a change in pressure in the water. The bow wave from the boat creates a large pressure differential that the fish can detect. Larger fish are usually fast enough to avoid the net as it moves through the water, but small fish can’t get out of the way in time. One night we caught several Pacific Ocean Perch, which are larger fish, but very slow moving. They are equipped with large spines on their fins and are better adapted to hunkering down and defending themselves as opposed to other fish that are fast swimmers and great at maneuvering.
This is one of the Pacific Ocean Perch (rockfish) that got caught in our net.
When we pull in the trawl net, it is emptied into buckets and then the haul is sorted by species and age class. The catch is then measured, weighed, and recorded on a data sheet. After that, we return most of the fish to the sea and save 25 of the juvenile pollock, capelin, and eulachon to take back to Seattle for further investigation. We also save some of the smaller flatfish and sablefish to send back to Seattle. Check out the gallery below to see the process from beginning to end.
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Where are the pollock in the food web?
Eulachon and capelin are zooplanktivores and compete with the juvenile pollock for food. Larger eulachon and capelin are not competitors (those over 150 mm). Arrowtooth flounder and Pacific Cod are predators of the juvenile walleye pollock. Cyanea and Chrysaora jellyfish are also zooplanktivores and could potentially compete with juvenile walleye pollock, so that is why we focus on these particular jellyfish in our study.
This Cyanea jelly weighed 11.6 kilograms!
One of the most common jellies that we see, Cyanea or Lion’s Mane Jelly.
Chrysaora
What’s in that net?
When we pull in the trawl, we sort it into piles of different species and different age classes. If we get a lot of juvenile pollock (age 0), we measure and weigh 100 and freeze 25 to take back to the lab so their stomach contents can be examined. We do the same procedure for young capelin, eulachon, and flatfish. Other organisms like jellyfish are counted and weighed and put back in the ocean.
Below is a list of different organisms we have found in the anchovy net during this cruise:
Every once in a while we find Pacific Cod juveniles, which look very similar to juvenile pollock.
A pink salmon that made its way into our net.
Sometimes all we catch in the net are jellies!
The top two arrowhead flounders are facing up and the bottom one is upside down. Notice the color variation. In flounders, both of the eyes have migrated to the top of the head.
A small pile of krill that was in our anchovy net.
Sometimes we net jellies and sometimes we net kelp, but we are really looking for pollock!
These are the larval stage of a fish belonging to the family Osmeridae. They are likely Capelin or Eulachon.
Small flatfish larvae.
Sand fish found in the trawl. Note the upward pointing mouth. (Photo credit: John Eiler)
A teeny tiny octopus! (Photo credit: John Eiler)
Herring (Photo credit: John Eiler)
Here I am holding a large arrowtooth flounder that was in our trawl.
The sharp teeth of an arrowtooth flounder.
The top fish is a Eulachon, the next is a Capelin, followed by a larval osmerid (could be a Capelin) and lastly, an age zero pollock.
Personal Log
As we wind down the cruise, I’m feeling a little sad that it’s ending. I’m looking forward to going home and seeing my husband and our dog, but I’ll miss the friends I’ve made on the ship and I’ll certainly miss collecting data. Even though it can be quite repetitive after awhile, I can’t think of a more beautiful place to do this work than the Gulf of Alaska. The last few days we have had a couple of stations near the coastline around Seward, Alaska and we have ventured into both Harris Bay and Resurrection Bay. There we caught sight of some amazing glaciers and small islands. There was even an island that had bunkers from WWII on it. Yesterday, 3 Dall’s Porpoises played in our bow wake as I stood on the bridge and watched. It’s moments like this that all of the discomforts of being at sea fall away and I can reflect on what an incredible experience this has been!
Beautiful scenery from Resurrection Bay.Three Dall’s porpoises that were playing in our bow wake.
Did You Know?
Spiny lumpsuckers are tiny, cute, almost spherical fish that have a suction disk on their ventral (bottom) side. The suction disk is actually a modified pelvic fin. They use the suction disk to stick to kelp or rocks on the bottom of the ocean.
Their family name is Cyclopteridae (like the word Cyclops!). It is Greek in origin. “Kyklos” in Greek mean circle and “pteryx” means wing or fin. This name is in reference to the circle-shaped pectoral fins that are possessed by fish in this family.
These lumpsuckers are well camouflaged from their predators and their suction disk helps them overcome their lack of an air bladder (this helps fish move up and down in the water). Because lumpsuckers don’t have an air bladder, they are not great swimmers.
Spiny lumpsuckers are on average about 3 cm in length, but there are larger lumpsuckers that we have found, like the toad lumpsucker that you can see in the photo below.
NOAA Teacher at Sea Louise Todd Aboard NOAA Ship Oregon II September 13 – 29, 2013
Mission: Shark and Red Snapper Bottom Longline Survey Geographical Area of Cruise: Gulf of Mexico Date: September 16, 2013
Weather Data from the Bridge: Barometric Pressure: 1014.01mb
Sea Temperature: 28.8˚Celsius
Air Temperature: 29.9˚C
Wind speed: 19.22 knots
Science and Technology Log:
Oregon II (Photo Credit NOAA)
We left Galveston a little before 2pm on Sunday, September 15. We were in transit to our first sampling location and should arrive there around 8pm tonight. Depending on the conditions we might actually be able to do some fishing tonight!
Today we went through our abandon ship drill. The ship’s alarm is used to alert everyone on board in the event of an emergency. Abandon ship is indicated by 7 short rings followed by one long ring of the alarm. When the alarm sounds with the abandon ship signal, we must carry our survival suits, personal flotation devices (PFDs), long pants, a hat and a long-sleeved shirt to the well deck, at the bow (front) of the ship. My survival suit and personal flotation device (PFD) are kept in cabinets in my room. The survival suit is tricky to get on and it gets very, very warm when you are wearing it!
In my survival suit (Photo Credit Lisa Jones)
Personal Log:
During this initial transit, there hasn’t been much for me to do. I spent a lot of time sleeping on Sunday. The way the waves rock the ship back and forth makes me very sleepy! I have taken a few short naps today in order to be ready in case we do any fishing on the later part of my shift tonight. I am on the day shift which means I will work noon to midnight. I think it will take me some time to get used to staying up that late but I think these naps will help! As we start fishing the days will be much busier for me so staying awake will be easy I hope. The views off of the ship are amazing. I was surprised to see how blue the water gets.
View off the Oregon II
My stateroom is very comfortable and I have plenty of space in drawers and cabinets for everything I brought with me. I am getting used to latching doors and drawers behind me so they do not slam back and forth as the ship rocks. On the ship there is always someone sleeping so everyone works hard to be courteous and stay quiet.
My stateroom
My roommate is an officer on the ship so we are usually in the room at different times. Officers on NOAA ships are part of the NOAA Corps. Roommates are usually assigned based on the shifts people are working so each person has some time alone in the room. As we start fishing more I will bring my computer and other items I might want throughout the day into one of the labs on the ship so I won’t have to go in and out of the room when my roommate might be sleeping. The curtains are helpful in blocking out any light that might prevent you from sleeping. The showers are right next to my room which is convenient and the common head (bathroom) is just around the corner.
There are plenty of food choices in the galley on the ship and everything has been delicious. In the mornings you can even get eggs made to order! I certainly don’t think I will be going hungry!
Did You Know?
Even in the warmer waters of the Gulf of Mexico, hypothermia is risk due to the difference in water temperature and our body temperatures. The survival suit helps to protect our bodies from the difference in temperature.
NOAA Teacher at Sea Susy Ellison Aboard NOAA Ship Rainier September 9-26, 2013
Mission: Hydrographic Survey Geographic Area: South Alaska Peninsula and Shumagin Islands Date: September 13, 2013
Weather: current conditions from the bridge
You can also go to NOAA’s Shiptracker (http://shiptracker.noaa.gov/) to see where we are and what weather conditions we are experiencing
GPS Reading: 55o 15.037’ N 162o 38.025’ W
Temp: 10.44C
Wind Speed: 9.8 kts
Barometer: 1021.21 mb
Visibility: foggy on shore
Science and Technology Log
Since leaving Kodiak 5 days ago, I have been immersed in a hydrographic wonderland. Here’s what I’ve learned, summed up in two words (three, if you count the contraction); it’s complicated. Think about it. If I asked you to make a map of the surface of your desk you could, with a little bit of work and a meter stick, make a reasonably accurate representational diagram or map of that surface that would include the flat surface, as well as outlines of each item on the surface and their heights relative to that surface, as well as their location relative to each other on a horizontal plane. You might want to get fancy and add notes about the type of surface (is it wood, metal, or some sort of plastic), any small irregularities in that surface (are there some holes or deep scratches—how big and how deep?), and information about the types of objects on the desk top (are they soft and squishy, do they change location?). Now, visualize making this same map if your desktop was underwater and you were unable to actually see it. Not only that, the depth of the water over your desktop can change 2 times each day. If that isn’t complicated enough, visualize that the top of the water column over your desk is in constant motion. OK, not only all those variables, but pretend you are transformed into a very teeny person in a small, floating object on that uncertain water over the top of your desk trying to figure out how to ‘see’ that desktop that you can’t actually see with your own eyes? Welcome to the world of the hydrographer; the challenge of mapping the seafloor without actually touching it. It is, indeed, a complex meld of science, technology, engineering, and math (STEM, in educational parlance), as well as a bit of magic (in my mind).
How do you know what’s down there?
Challenge number one—how do you measure something you can’t see or touch with your own hands? Long ago, sailors solved that obstacle by using a lead line; literally, a line with a lead weight attached to the end. They would drop the weighted line over the side of their ship to measure the depth. These soundings would be repeated to get enough data to provide a view of the bottom. This information was added to their maps along with estimates of the horizontal aspects (shoreline features and distance from the shoreline) to create reasonably good charts that kept them off most of the underwater obstacles. A simple solution to a complex problem. No electricity required, no advanced degrees in computer science needed, no calculus-based physics necessary. Fast- forward to 2013 and the world of complex calculations made possible by a variety of computer-based algorithmic calculations (i.e. some darn fancy computing power that does the math for you). The NOAA Ship Rainier’s hydrographers use sound as their lead line, traveling in small boats known as launches that are equipped with multibeam sonar that send a series of sound ‘pings’ to the ocean floor and measures the time between sending and receiving the ping back after its trip to the bottom. Sounds simple enough, doesn’t it? If it were all that simple I wouldn’t be typing this in a room on the Rainier filled with 20 computer monitors, 10 hard drives, and all sorts of other humming and whirring electronic devices. Not only that, each launch is equipped with its own impressive array of computer hardware.
One of the launches is lowered from the ship.
So far on our survey days 2 launches have been sent out to cover identified transects. Their onboard crew includes a coxswain (boat driver), as well as 2-3 survey technicians and assistants. Each launch is assigned a polygon to survey for the day.
EVERY PING YOU TAKE…
Once they arrive at their assigned area, it’s time to ‘mow the lawn’—traverse back and forth systematically collecting data from one edge of your assigned polygon to the other until the entire area has been surveyed. Just in case you haven’t realized it yet, although that sounds pretty straightforward, it isn’t. Is the area shallow or deep? Depth affects how much area each traverse can cover; the sonar spreads out as it goes downward sending it’s little pings scampering to the ocean floor. Visualize an inverted ‘V’ of pings racing away from the sonar towards the sea floor. If it’s deep, the pings travel further before being bounced back upwards. This means that the width of each row the sonar cuts as it “mows the lawn” is wider in deeper water, and narrower in shallow. Shallower areas require more passes with the launch, since each pass covers a more limited area than it might if the water were deeper. As the launch motors back and forth ‘mowing the lawn’, the sonar signature is recorded and displayed on monitors in the cabin area and in front of the driver. Ideally, each lap overlaps the previous one by 25-50%, so that good coverage is ensured. This requires a steady hand and expert driving skills as you motor along either over or parallel to ocean swells. All you video gamers out there, take note–add boat driving to the repertoire of skills you might need if you want to find a job that incorporates video gaming with science!
One of the monitors displays the sonar. The green line is the seafloor. This image shows that the deeper the sea, the wider the swath that is covered with each pass of the launch.Calvin Burch uses a computer monitor to guide him as he drives the launch. It’s an art to ‘mow’ in straight lines while anticipating every roll and bounce of the ocean’s surface.
Here’s a small list of some of the variables that need to be considered when using sonar to calculate depth; the chemistry of the water column through which you are measuring, the variability of the water column’s depth at specific times of day, the general depth (is it shallow or deep), and the movement of the measuring device itself. So many variables!!
Starla Robinson and Randy Shingledecker set up the program that will enable them to monitor our progress
HOW FAST DOES SOUND TRAVEL?
When you’re basing your charts on how sound travels through the water column, you need to look at the specific characteristics of that water. In a ‘perfect world’, sound travels at 1500m/second through water. In our real world, that speed is affected by salinity (the concentration of salts), temperature, and depth (water pressure). The survey crew uses a CTD meter to measure Conductivity, Temperature, and Depth. The CTD meter is deployed multiple times during the day to obtain data on these parameters. It is attached to a line on the rear of the launch, dropped into the water just below the surface for 2 minutes, and then lowered to near the ocean floor to collect data. After retrieval, it’s hooked to the computer on the launch to download the data that was collected. That data is stored in its own file to use when the data is reviewed in the evening back on board the Rainier. This is one of the variables that will be applied to the sonar data file—how fast was the sound moving through the water? Without this information to provide a baseline the sonar data would not be accurate.
Randy Shingledecker gets ready to send the CTD over the side. It’s clipped into a stout line and a reel for lowering it.The CTD is lowered to just above the seafloor to collect data on Conductivity, Temperature, and Depth. This data will be applied to our sonar data to obtain an accurate sound speed for this area.
ROCKING AND ROLLING…
When you’re out on the ocean in a boat, the most obvious variable is the instability of the surface, itself. This is called ‘attitude’. Attitude includes changes to the boat’s orientation fore and aft (pitch), side-to-side (roll), and up and down (heave) as it is gently, and not-so-gently rocked by ocean swells and waves. This means that the sonar is not always where you think it is in relation to the seafloor. This is like trying to accurately measure the height of something while you, the measurer, are on a surface that is constantly moving in 3 different directions. Good luck. Luckily for this crew of hydrographers, each boat is equipped with a little yellow box whose technical name is the IMU (inertial measurement unit) that I call the heave-o-meter, as we bob up and down on this might ocean. This little box contains 3 gyroscopic sensors that record all those forward and backward pitches, sideways rolls, as well as the bobbing up and down motions that the boat does while the sonar is pinging away. This information is recorded in the launch’s computer system and is applied to the sonar data during analysis back at the Rainier.
This yellow box is the IMU. It’s internal gyros capture information about the boat’s pitch, roll, and heave.
TIME AND TIDE…
Now that you’ve gotten your launch to the correct polygon (using GPS data to pinpoint your location), taken CTD readings to create a sound transmission profile for your transect area, and started up the heave-o-meter to account for rocking and rolling on the high seas, it’s time to start collecting data. Wait—there’s still another variable to think about, one that changes twice daily and affects the height of the water column. You also have to factor in changes in the depth of the water due to tidal changes. (for an in-depth look at how tides work, check out this link: http://oceanservice.noaa.gov/education/kits/tides/tides01_intro.html). At high tide, there’s a greater likelihood that subsurface obstacles will be covered sufficiently. At low tide, however, it’s pretty important to know where the shallow spots and rocks might lurk. NOAA’s hydrographers are charting ocean depths referenced to mean lower low water, so that mariners can avoid those low-water dangers.
You might be asking yourself, who keeps track of all that tide data and, not only that, how do we know what the tide highs and lows will be in an area where there are no other tide gauges? NOAA has tide gauges along many coastal areas. You can go online to http://tidesandcurrents.noaa.gov/and find out predicted tide heights and times for any of these locations. While we are working here in Cold Bay, we are using a tide gauge in nearby King Cove, as well as a tide gauge that the Rainier’s crew installed earlier this summer. More data is better.
Here’s the tide chart from the King Cove tide gauge.
What do you do if you’re surveying in an area that doesn’t have existing tide gauges? In that case, you have to make your own gauge that is referenced to a non-moving point of known elevation (like a rock). For a detailed description of how these gauges are set, check out NOAA TAS blogs from some of the teachers who preceded me on the Rainier. On Wednesday, I helped dismantle a tide gauge on Bird Island in the Shumagin Islands that had been set up earlier this season (check out TAS Avery Martin’s July 12th posting), but had ceased to report reliable data. Our mission on Wednesday was to find out if the station had merely stopped reporting data or if it had stopped collecting data entirely.
Setting off in a skiff to check on the Bird Island tide gauge.
When we arrived at Bird Island we found out exactly why the gauge had stopped sending data—its battery bank had fallen from one rocky ledge to another, ripping apart the connections and breaking one of the plastic battery boxes in the process. That took a lot of force—perhaps a wave or some crazy gust of wind tore the 3 batteries from their mooring. Since each battery weighs over 25lbs, that means that something moved over 75lbs of batteries. Ideally, the station uses solar panels to keep the batteries charged. The batteries power up the station so that data can be sent to a satellite. Data is also stored on site in a data logger, but without power that data logger won’t work.
This is the data logger for the tide gauge. It is housed in a watertight box and was retrieved for downloading on the ship.
We retrieved all the equipment and will be able to download whatever data had been recorded before the system broke. The automated tide gauge is, basically, a narrow diameter air-filled tube that is underwater and set at a fixed depth with a narrow opening pointed downward to the seafloor. The pressure required to balance the air in the tube is equal to the pressure of the water column directly above the opening. The tide gauge measures this pressure and converts it to depth. Pressure/depth changes are recorded every six minutes—or ten times each hour. As it turns out, the damaged battery bank was only one of the problems with this station. Problem number two was discovered by the dive team that retrieved the underwater portion of the gauge; the hose had been severed in two locations. In this case, something had caused the tube to break, so it was no longer connected to the data logger. That must have been some storm!
ENS Carrier inspects the battery bank that rests on a rock ledge 2 feet below where it had been placed weeks ago!The waterproof battery boxes were broken in the tumble.The solar panels that charged the batteries were intact, still tied into bolts in the rocks.The dive crew gets ready to jump inBrrr, it’s chilly work diving in arctic waters. The divers are investigating the gauge and removing the damaged hose
While there, we set to work checking on benchmarks that had been set earlier in the season. We used a transit and survey rods (oversized rulers) to measure the relative heights of a series of benchmarks to ensure accuracy. There are 5 benchmarks along the beach. Each one was surveyed as a reference to the primary benchmark nearest the gauging station. Multiple measurements help ensure greater accuracy.
I am holding the survey rod on top of a benchmark.
I used a level to make sure the rod was plumb–perpendicular to the benchmark. No easy feat with a strong wind blowing!
We also were tasked with checking the primary benchmark’s horizontal location. While this had been carefully measured when it was set back in July, it’s important to make sure that it hasn’t moved. It might seem a crazy concept to think that a benchmark cemented into a seemingly immovable piece of rock could move, but we are in a region that experiences seismic events on an almost daily basis. (You can check out seismic activity at http://www.aeic.alaska.edu/) NOAA Corps Officer ENS Bill Carrier set up a GPS station at the benchmark to collect 4 hour’s data on its position, a process called HORCON (horizontal control). Unfortunately, the winds were in charge of how much data we were able to collect that day, and blew down the station after only 3 hours! [image of station down] Sometimes the best laid plans …..
A gust of wind blew the recording station down.
DATA, DATA, and MORE DATA
While data collection is important, it’s what you do with the data that really gets complicated. Data management is essential when working with so many files and so many variables. Before each launch returns to the Rainier, the day’s data is saved onto a portable hard drive. Immediately after being hauled back up onto the ship, the data is handed off to the ‘Night Processing Team’ and hustled off to the Plotting Room (computer HQ) to be uploaded into a computer. This is where the magic happens and an advanced degree in computer science or GIS (geographic information systems) can come in handy. I have neither of those qualifications, but I know how to read a screen, click a mouse, and follow directions. So, on Friday evening I was ushered into the ranks of ‘night processor’.
When each launch returns to the ship, their day’s data is saved onto a hard drive. This drive is transported to the plotting room to download onto the computer.
First, data is downloaded into the main computer. Each launch’s files are called raw data files and are recorded in the launch’s acquisition logs. Once the data is on the computer, it is important to set up what I call a ‘file tree’; the series of files that increase in specificity. This is analogous to having an accurate list of what files live within each drawer and section of your file cabinet. These files are color-coded according to the operations manual protocols to minimize the chance of misfiling or the data. They are definitely more organized than the files on my laptop—I might change my lackadaisical filing ways after this trip!
Once the data are placed in their folders, the fun begins. Remember, you have files for multiple variables; sonar, CTD casts, the IMU Heave-o-meter, and tide data. Not only that, you have, with any luck, performed multiple casts of your CTD meter to obtain accurate data about the conditions affecting sound wave transmission within your polygon. Now you get to do something I have never done before (and use a vocabulary word I never knew existed and one that I might try to spell in a future Scrabble game); you concatenate your CTD data. Basically, you put the data from all your CTD casts together into one, neat little file. Luckily, the computer program that is used does this for you. Next, you direct the program to add all the variables to your sonar files; the concatenated CTD data, tide data, and IMU data.
Survey Tech Brandy Geiger and NOAA Corpsman ENS Wall begin to upload the data and organize it into files.
Assuming all goes well and you have merged all your files, it’s time to ‘clean’ your data and review it to make sure there are no obvious holes or holidays in the data that was collected. Holidays can occur if the launch was bouncing too much from side to side during data collection and show up as a blank spot in the data because the sonar was out of the water and not pinging off the bottom. You can identify these holidays during the data collection process [holiday signature], but sometimes there are smaller holidays that show up once the data is merged and on your computer screen. There can also be miscellaneous errant pings caused by debris in the water column. Cleaning involves systematically searching each line of your surveyed polygon to identify and delete those ‘bad’ pings. Kind of like photoshopping away the parts of a digital image that you don’t want in the final image. You work methodically in a grid pattern from left to right and top to bottom to ensure that you are covering the whole file. It sounds easy, but to a non-PC person such as myself all that right click, left click, center click stuff was a bit boggling. The program is amazingly complex and, rumor has it, a little bit ‘buggy’ at times.
Multiple screens, multiple tasks. I am learning the art of ‘cleaning’ the data–getting rid of extraneous pings.
After all this, guess what?! You still don’t have a chart. It takes almost 2 years to go from data collection to chart publication. There’s endless amounts of data compilation, reports to be written, and quality control analysis to be completed before the final report and charts are issued.
Personal Log
So far I have spent two nights on the ship ‘in transit’, moving between ports. The other nights have been spent anchored offshore. While the first night at sea was a little bouncy, the second was, in my opinion, the wildest roller coaster ride I have ever taken. Imagine being pulled to the top of a high roller coaster, and released to fly down to the bottom while you are lying flat in your bed. That’s what it felt like as we motored from the Shumagin Islands to an anchorage in Cold Bay. An endless series of up, up, ups, followed by a wild ride down, down, down. Luckily all the drawers and doors have latches that keep them from flying open—although I had a jacket hanging on a hook that seemed to hit the latch on one closet door and actually knock it open—after this happened a couple of times I gave up and put the coat on the floor and firmly shut the door. My bathroom trash can ended up in the shower stall. At one point I heard a loud thump in the dark—and realized my survival suit in its orange bag had fallen from the top bunk to the floor—glad I wasn’t in its way! It was time to just hang on and try not to roll out of bed.
If your chair isn’t tied down, put tennis balls over the wheels to keep it from rolling!Strap the printer tightly to a table!Don’t forget to secure the trashcans!
We finally stopped rocking and rolling around 3 in the morning. I thought maybe I was just a bit sensitive to the rocking motion, but was comforted to find out the everyone agreed that it had been a wild night. In fact, one of the potential ‘hazards’ for our work on Thursday was ‘lack of sleep’.
FOO LT Meghan McGovern goes over the Plan of the Day (POD). Today’s identified hazards included ‘Lack of Sleep’.
After almost a week aboard the Rainier I have been impressed with the teamwork, precision, and overall efficiency which overlays all operations. This crew can get a launch loaded, lowered, and underway in less time than it sometimes takes me to record my morning attendance at school! This is no simple feat (the boat, not the attendance!). It reminds me of a buzzing beehive filled with activity and focused on a single task; data collection. Each day begins on the fantail (the rear of the boat) at 0800 with the FOO (Field Operations Officer) reviewing the POD (Plan of the Day) and a summary of the day’s goals, work assignments, weather, and potential hazards, prior to sending out the survey crews.
The Boatswain (bo’sun) directs the next part of this tightly choreographed activity, as the launches are lowered by their davits (small cranes), while lines and hooks are handled with an eye to safety and efficiency. Within 5 minutes the two launches have been lowered, loaded with crew and supplies, and are on the water, buzzing away from the hive like bees to perform their daily waggle dance as they move back and forth collecting hydrographic data.
At 1630 they return to the hive, filled with the sweet nectar of hydrographic data. Launches are lifted back onto the ship and the data is whisked off to the computer room for downloading. 5 Minutes later a survey team debrief is held to review work accomplished that day and any problems that may have come up so that plans can be made for the next day’s work. This crew is organized!!
