Chris Henricksen: Doing Science at Sea, May 12, 2014

NOAA Teacher at Sea

Christopher Henricksen

Aboard NOAA Ship Henry B. Bigelow

May 6 – May 16, 2014

Geographical area of cruise: Georges Bank
Mission: Spring Bottom Trawl & Acoustic Survey
Date: May 11, 2014
Air Temp: 11.2°C (52.16°F)
Relative Humidity: 100%
Wind Speed: 21.9mph
Barometer: 1010.5mb

Science and Technology Log

Here’s what a typical watch aboard the Henry B. Bigelow looks like.  Upon assuming the watch, which in my case means beginning work at midnight, the science team gets a rundown of what happened during the previous watch.  When the ship nears its next station (where it will drop the net and begin trawling), the area is surveyed to ensure that it is clear of lobster traps and large rocks before readying the nets for trawling.  Think of the trawl nets in terms of really large butterfly nets, except these nets also contain a set of sensors that tell the science team and the Officer of the Deck (the officer in charge of driving the ship) information about how deep the net is, how fast it’s traveling, etc..  The ship’s deckhands lower the nets from the aft (rear) deck of the ship into the water and then closely monitor them until reaching a specified depth.  With the trawl nets in place, the ship steams at 3 knots for about twenty minutes, pulling the nets along and catching fish and other marine life.  Once the trawl is complete, the net is hauled aboard and it’s time for the scientists to get involved.

picture of trawl net

Hauling the trawl net aboard the Henry B. bigelow

checker

Chris Henricksen

Using a crane, the net is swung over a large stainless steel hopper called the checker.  A scientist working the checker, then pushes the captured organisms onto a conveyor belt, which moves them inside the ship to the wet lab.  In the wet lab, scientists and volunteers (like me) stand along a long conveyor, sorting the catch by species and, sometimes, by sex or size, into a set of buckets.  After the catch is sorted, the buckets are consolidated and placed on another conveyor belt, which moves the buckets to the Watch Chief’s station.  The Watch Chief scans a barcode on the side of each bucket, and uses a computer to assign a species to that barcode.  The barcoded buckets are each filled with a different organism then moved to any one of three cutter stations for processing. The Cutter scans the barcode of an available bucket, which tells the computer at his or her station some basic information about the organism, such as its scientific and common names, and how much the bucket weighs.  The computer also tells the Cutter what sorts of protocols need to occur on that organisms (weighing, measuring, checking stomach contents, determining sex).  As the Cutter processes the organism, the Recorder, standing at a computer screen next to the Cutter,  assists the Cutter by inputting measurement and other data into the computer system.  Often, extra instructions pop up on the screen, instructing the Cutter that a scientist has requested that we collect specimens from an organism.  Otoliths (ear bones from fish) are collected frequently, but sometimes a request is made to freeze or preserve an organism.  Some organisms even go in a live holding tank so the scientist can have a living specimen when the ship returns to port.  This entire process can take anywhere from one hour to several, depending on the amount fish and the types of processing required.

pic of sorting line

Scientists sorting organisms for survey

Personal Log

Well, yesterday (Saturday) was a rough one for yours truly.  We ran into some higher seas, and the ship’s rocking and rolling made me sick as a dog.  So much for that Navy experience helping me in this regard…  Oh, well, that’s part of life at sea.  Everyone was very kind about it. one of my watchmates even fetched some crackers for me, which helped.  Feeling much better today. Here are a few pictures representing life aboard the Henry B. Bigelow (at least as I live it):

pic of galley

The Galley

pic of menu

Dinner menu – good food!

pic of stateroom

My stateroom. I sleep in the bunk with the open curtains

pic of head

The Head (bathroom) in my stateroom

Dave Murk: Three 2’s From the Okeanos Explorer, May 10, 2014

NOAA Teacher at Sea
Dave Murk
Aboard NOAA Ship Okeanos Explorer
May 7 – 22, 2014

Mission: EX 14-03 – Exploration, East Coast Mapping
Geographical Area of Cruise: Off the Coast of Florida and Georgia – Western portion of the Blake Plateau (Stetson Mesa)
Date: May 10, 2014

Weather data from Bridge:
Temperature 25 degrees celsius (can you convert to Fahrenheit?)
WInd – From 160 degrees at 14 knots (remember north is 0 degrees)
Latitude : 28 degrees  – Longitude: 79 degrees.

 

Science and Technolgy Log:

Two of the goals for this expedition. (There are a lot more)

Expedition coordinator Derek Sowers said his best case scenario for this mission is to meet all the cruise objectives. The main one- an aggressive 24/7 campaign to map as much seafloor as possible within top priority mapping areas offshore of the Southeast United States and along the canyons at the edge of the Atlantic continental shelf.

L – R – Chief Scientist Derek Sowers, Vanessa Self-Miller, Kalina Grabb

In addition to that mapping goal, he wants the visiting fisheries scientist on board to get good water samples for the Ocean Acidification Program and good samples from the plankton tows. Last but not least, he “wants the mission team to have a great learning experience.”

The ship has three different sonars, each of which is good for different things. One sonar sends out a single beam of sound that lets you see fish and other creatures in the water column. Another sonar sends powerful sounds that bounce back off the bottom and gives you information about the geology (rocks and sediment) of the seafloor. Perhaps the most impressive sonar onboard is the multi-beam sonar. You know how your garden hose has a setting for jet spray when you want to aim it at your brother who is 10 feet away? The water comes out in a straight narrow line. But there’s also another setting called ‘shower” or wide spray. The multibeam sonar is like combining the best of both of these sprays into one and sends out a fan of sound that allows the scientists to map a broad section of the seafloor. By measuring how long it takes this sound to reach a patch of seafloor and return to the ship, it is possible to estimate the distance and that is how the shape of the seafloor can be mapped. Using this technology enables NOAA to map the seascape in order to better protect marine habitat and reduce harm from human activities. Mapping the marine protected areas off the east coast of Florida and Georgia is important because there are deep sea corals in this area and it is important fisheries habitat.

Chris Taylor – NOAA Fisheries

This cruise features a visiting scientist from NOAA Fisheries, named Chris Taylor. Chris’s part of the expedition includes collecting water samples and towing a net that can collect very small creatures called plankton. Chris is specifically examining the plankton he catches to see if bluefin tuna use this part of the ocean to lay eggs and raise young tuna. Samples from the net will go back to a lab to be analyzed to make sure they are bluefin and not yellowfin tuna.

Chris spent most of this windy but warm night tying a rope to the net that he’ll use for HOPEFULLY – catching some baby Bluefin Tunas. Like insects, Bluefin tuna go through an egg stage THEN a larva stage. When they are very small they drift with the currents with the rest of the ocean community. Once a larva is over 7 millimeters, they can avoid the net. But If we find some Bluefin tuna – it may mean that we have found a new spawning ground for Bluefin tuna in the southern North Atlantic.

Personal Log:

Lt. Emily Rose instructs AB Tepper-Rasmussen in radar navigation techniques.

Two people who make this ship run so well:The operations officer – Lieutenant Emily Rose. Officer Rose can usually be found on the bridge of the NOAA ship Okeanos Explorer. Today she was teaching a course on small craft navigation before I caught up with her. The thing she really loves about this position is that there are new set of challenges each day. She is always learning (and I’ll add that she is almost always sharing that knowledge with others) but the ship is her first responsibility. The most difficult thing is getting up every morning before 3:00 a.m. and being away from everyone back home.

 

 

Electronics Technicians Conway and Okeson

Chief Electronics Technician Richard Conway and Electronics Technician Will Okeson are the Tech guys and they are always busy. Since Okeanos Explorer is America’s premier ocean exploration ship, there are a lot of computers, miles of cable and lots of video equipment to maintain. Richard and Will’s favorite part of the job is when all the parts work together and the public can see their product and when they can trouble shoot and help the science team reach their objectives. The most difficult thing it so be away from families when there is a crisis or joyous moment.

Two things about my personal experiences so far on EX-14-03 (our mission)

Using photometer to monitor aerosol properties. (photo taken by Mapping Intern Kalina Grabb

Using photometer to monitor aerosol properties. (photo taken by Mapping Intern Kalina Grabb

First – – “SCIENCE RULES” to quote Bill Nye. Every Okeanos Explorer crew member and scientific crew member are all about the science of the mission. When one of the science crew is going to launch something called an XBT over the side, they call and get an OK from the bridge (where the captain or second in command and the crew that are on “watch” are located). No one hesitates to ask questions of each other. Why is this? What is that? Where is the nearest ship? What’s for lunch? (just kidding ! Chief Steward Randy posts a menu every day and it beats out Golden Corral any day of the week for tastiness and diversity). But the important thing of the mission is the science and every single person on the ship works to make the mission a success.

Second – RESPECT – There is so much respect shown on the Okeanos Explorer. It’s respect for other people, for the ship, for the environment, for rules and for commons spaces.  Yesterday while on the bridge, Ensign Nick Pawlenko was taking over from Commander Ramos and they both showed such respect for rules and for each other by going over all the observations of the ship’s speed, the weather conditions and whether there were any other ships in the area.  When breakfast was over – I saw Operations Officer Rose stick her head in the galley (kitchen) and thank Chief Cook Ray and Chief Steward Randy for a great meal. No one slams doors since it might wake the crew and scientists who are on night duty. Everyone cleans up after themselves. If you ever have a question and if the crew or scientists can answer it, they will. There is respect for the environment when we separate our garbage each meal.   If only the whole world was like the Okeanos.

 

MYSTERY PICTURE – Here are two photos – what’s different about them? And WHY?? That’s the million dollar question (or an even better prize –bluefin tuna larva in our trawl nets )

IN the mess (dining area)

(see anything different?)

(see anything different?)

 

 

 

 

 

 

 

 

Denise Harrington: Post Processing — Final Days, May 2, 2014

NOAA Teacher at Sea
Denise Harrington
Aboard NOAA Ship Rainier
April 20 – May 3, 2014

Geographical Area of Cruise: North Kodiak Island

Date: May 2, 2014, 23:18

Location: 57 43.041’ N  127o 152.32.388’ W

Weather from the Bridge: 13.09C (dry bulb), Wind 1 knots @ 95o, clear, 0′ swell, balmy “crazy nice weather”  say Able Seaman Jeff Mays

Our current location and weather can also be seen at NOAA Shiptracker: http://shiptracker.noaa.gov/Home/Map

Science and Technology Log

Today’s blog is all about post processing, or “cleaning up” the data and being on night shift.  It is a balmy, sliver moon night at port here, in Kodiak.  We have come a long way in the last two weeks, during which survey crews have been working hard to finalize a Cold Bay report from last season before they devote themselves entirely to North Kodiak Island. I am in the plot room with Lieutenant Junior Grade Dan Smith who is on Bridge Duty from midnight until 4 a.m. with Anthony Wright, Able Seaman.

Able Seaman Anthony Wright consults with Ensign Steven Wall about conditions on the bridge and other things.

Able Seaman Anthony Wright consults with Ensign Steven Wall about conditions on the bridge and reports “all conditions normal.”

People work around the clock on Rainier whether it be bridge watch, processing data, or in the engine room.  One thing that makes the night shift a little easier is that there is no shortage of daylight hours in Alaska: within two months, there will be less than an hour of complete darkness at night.

After watching Commander Brennan guide us north, and seeing all the work it entails,  it is a great sight to see him enjoy a 10 p.m. sunset.

After watching Commander Brennan guide us north, with all the work it entails, it is a great sight to see him enjoy a 10 p.m. sunset with his wife (by phone).

In previous blogs, I described how the team plans a survey, collects and processes data.  In this blog, I will explain what we do with the data once it has been processed in the field. Tonight, Lieutenant Dan Smith is reviewing data collected in Sheet 5, of the Cold Bay region on the South Alaskan Peninsula.  In September, 2013, the team surveyed this large, shallow and therefore difficult to survey area.  The weather also made surveying difficult.  Despite the challenges, the team finished collecting data for Sheet 5 and are now processing all the data they collected.

Cold Bay Sheet Map

Cold Bay Sheet Map.  Recall the shallow areas are shaded light blue, and as you can see much of the north end of Sheet 5 is blue.

While I find editing to be one of the most challenging steps in the writing process, it is also the most rewarding.  Through the editing process, particularly if you have a team, work becomes polished, reliable and usable.  The Rainier crew reviews their work for accuracy as a team and while Sheet 5 belongs to Brandy Geiger, every crew member has played a part in making the Sheet 5 Final Report a reality, almost.  On the left screen, Lieutenant Smith is looking at one line of data.  Each color represents a boat, and each dot represents the data from one boat, and each dot represents a depth measurement  computed by the sonar. The right screen shows which areas of the map he has already reviewed in green and the areas he still needs to review in magenta.

Dan looks for noise after midnight.

Lieutenant Smith looks for noise after midnight.

While the plot room is calm today in Kodiak, there have been times when work conditions are challenging, at best. .

The crew continues on, despite the weather, so long as work conditions are safe.

Several days ago, Lieutenant Smith taught me the difference between a sonar ping that truly measured depth, and other dots that were not true representations of the ocean floor.  Once you get an eye for it, you kill the noise quickly.  In addition, when Lieutenant Smith finds a notable rise in the ocean floor he will “designate as a sounding.”  Soundings are those black numbers on a nautical chart that tell you how deep the water is.

This line shows three colors, meaning three boats sent pings down to the ocean floor in this area.

This line shows three colors, meaning three boats sent pings down to the ocean floor in this area.

If the line has dots that rise up in a natural way, the computer program recognizes that these pings didn’t go as far down as the others and makes a rise in the ocean floor indicated with the blue line.  It is the hydrographer’s job to review the computer processed data.  One of the differences between a map and a nautical chart is the high level of precision and review to ensure that a nautical chart is accurate.

This nautical chart went through many layers of analysis, processing and review before becoming published as a  nautical chart that can be used as a legal document.

This nautical chart of Cold Bay went through many layers of analysis, processing and review before becoming published as a nautical chart that can be used as a legal document. It may be updated after Brandy Geiger and NOAA’s hydrography work in the area is completed.

This is a topographical map of the same area, Cold Bay, that provides some information about landmarks but not necessarily the same legal standing or authority.

This is a topographical map of the same area, Cold Bay, that provides some information about landmarks but not necessarily the same legal standing or authority.

NOAA has several interesting online resources with more information about the differences between charts and maps: http://oceanservice.noaa.gov/facts/chart_map.html .

Now let’s kill some noise on this calm May evening.

In this image of a shipwreck on the ocean floor most sonar pings reached the ocean floor or the shipwreck and bounced soundings back to the survey boat.  Look carefully, however, and you see white dots, representing pings that did not make it down to the ocean floor.  Many things can cause these false soundings.  In this case, I predict that the pings bounced back off of a school of fish.  Here, the surveyor kills the “noise” or white pings by circling them with the mouse on his computer. It wouldn’t be natural for the ocean floor or other feature to float unconnected to the ocean floor, and thus, we know those dots are “noise” and not measurements of the ocean floor.

Lieutenant Smith estimates that at least half of his survey time is spent in the plot room planning or processing data.  The window of time the team has in the field to collect data is limited by weather and other conditions, so they must work fast.  Afterward, they spend long, but rewarding hours analyzing the data they have collected to ensure its accuracy and to provide synthesized information to put into a nautical chart that is easy to use and dependable. Lieutenant Smith believes that in many scientific careers, as much time or more time is spent planning, processing and analyzing data than is spent collecting data.

 

Personal Log

As we post process our data, I too, begin post processing this amazing adventure.  I am hesitant to leave: I have learned so much in these two short weeks, I want to stay and keep learning.  But at NOAA we all have many duties, and my collateral, wait–my primary duty is to my students and so, I must return to the classroom.  I will leave many fond memories and a camera, floating somewhere in Driver Bay, behind me.  I will take with me all that I have learned about the complexity of the ocean planet we live on and share my thirst to know more back to the classroom where we can continue our work. I will miss the places I’ve seen and the people I met but look forward to the road or channel of discovery that awaits me and my students.

I am also taking with me a NOAA flag, full of memories from the North Kodiak Island crew and my new friends.

I am also taking with me a NOAA souvenir flag, full of memories from the North Kodiak Island crew — my new friends.

Did You Know? The Sunflower Sea Star is the largest and fastest moving sea star travelling up to one meter per minute.

Here we taking a quick break during a tide gauge set up to look at sea stars and anemones.

Here we taking a quick break during a tide gauge set up to look at sea stars and anemones.

Below are a few photo favorites of my time at sea.

Chris Henricksen: Standing My First Watch, May 8, 2014

NOAA Teacher at Sea

Chris Henricksen

Aboard NOAA Ship Henry B. Bigelow

April 29–May 10, 2014

Geographical area of cruise: Gulf of Maine

Mission: Spring Bottom Trawl & Acoustic Survey

Date: May 7, 2014

Air Temp: 9.1°C (48.38°F)

Relative Humidity: 73%

Wind Speed: 10.83mph

Barometer: 1011.7mb

 

 

Science and Technology Log

My section stands watch from midnight to noon–twelve hours on, twelve hours off.  Today I stood my first watch, acting as one of three “recorder” on the fish sorting line.  A recorder’s role is to assist his assigned “cutter” by entering requested measurement data (e.g., length, weight, etc.) of individual fish into a computer database.  The cutter processes fish by identifying the species, then performing any number of actions (i.e., cuts, as in, with a knife) in order to retrieve information about particular fish for later use by scientists.  Such data will consist of measuring, weighing, and sexing the fish, as well as checking the contents of its stomach.  Other particular data may be gathered, such as collecting otoliths (ear bones) from the head of the fish.

photo of net prep

Preparing the net for our first trawl

After getting underway, the captain called a series of drills, one of which was abandon ship.  During this exercise, I reported to the aft deck of the ship, donned a “Gumby” survival suit, which is bright orange/red, keeps you warm while in the water, and helps you to stay afloat.  Following that, we had a collision drill.  In a disaster scenario, everyone has a muster station, so that we can be counted, and then help control the situation, if need be.

photo of abandon ship drill

Abandon Ship Drill

Today was my first of about a dozen watches I will stand.  It went smoothly, but there was considerable down time.  The first stations (the areas in which the nets are lowered and trawling begins) were about 25 nautical miles from one another, so it took a couple of hours to steam from one station to the next.  During this time, I was able to relax, grab a bite, or hang out with other members of my watch. Personal Log The food aboard ship is very good, and there is plenty of it. Between mealtimes, the cook makes sure that plenty of drinks and snacks are available, so there is no reason to go hungry aboard the Henry B. Bigelow. The ship has a huge library of DVDs with many new movies.  We can also watch TV thanks to a satellite connection (DirectTV). The only things I am not allowed to do are 1) re-enter my stateroom after going on watch, as there is always an off-watch shipmate trying to catch some shuteye, and 2) make a surprise appearance on the bridge, which is where the NOAA officers navigate and steer the ship.  That’s for safety, and I am sure they would welcome me, as long as I called ahead first. I am tired, but feeling pretty good.  I boarded the ship wearing an anti-motion sickness patch, fearing that, after twenty years of not being at sea, I might be susceptible to seasickness.  The medicine made me feel awful, so I took it off, and now feel much better!  I had almost forgotten how much I enjoy the rocking of a ship.  It’s an especially good way to fall asleep–gently rocking…

2014-05-06 deck selfie

Deck Selfie!

Denise Harrington: The Best Day Ever, April 30, 2014

NOAA Teacher at Sea
Denise Harrington
Aboard NOAA Ship Rainier
April 20 – May 3, 2014

Mission: Hydrographic Survey

Geographical Area of Cruise: North Coast Kodiak Island

Date:  April 30, 2014, 11:44 a.m.

Location: 58 03.175’ N  127o 153.27.44’ W

Weather from the Bridge: 6.3C (dry bulb), Wind 5 knots @ 250o, clear, 1-2′ swell.

Our current location and weather can also be seen at NOAA Shiptracker: http://shiptracker.noaa.gov/Home/Map

Science and Technology Log

The last couple of days have been the best ever: beautiful weather, hard work, deep science. We acquired data along the continental shelf and found a cool sea floor canyon and then set benchmarks and tidal gauges.

In hydrography, we gather data in seven steps, by determining: our position on Earth, depth of water, sound speed, tides, attitude (what the boat is doing), imagery and features.  Step 1 is to determine where we are.

In this picture you can see a GOES satellite antenna and a GPS antenna that helps us determine our precise location.

In this picture you can see a GOES satellite antenna (square white one) that is used to transmit tide data ashore and a GPS antenna (the small white eggs shaped one) that provides the tide gauge with both position and UTC time. Photo by Barry Jackson

In this picture  Brandy Geiger, Senior Survey Technician, uses the GOES from various locations to determine the exact location of the tide gauge.

In this picture Brandy Geiger, Senior Survey Technician, uses GPS to record the positions of the benchmarks we have just set for the tide gauge. Photo by Barry Jackson

tide gauge install 023

Where we are happens to be the most beautiful place on earth. Photo by Barry Jackson

 

In Step 2, we determine the depth of the water below us.

Bathymetry is a cool word that means the study of how deep the water is.  Think “bath” water and metry “measure.”  When your mom tells you to get out of the tub, tell her to wait because you’re doing bathymetry.

As I explained in my first blog, we measure depth by sending out a swath of sound, or “pings,” and count how long it takes for the pings to return to the sonar, which sits beneath the ship or smaller boat.

Yesterday we used the multi-beam sonar to scan the sea floor.  Here is a screen shot of the data we collected.  It looks like a deep canyon, because it is!

Here is the image of the trench Starla Robinson, a Senior Survey Technician, and I discovered.  We decided it should be named Denla Canyon, after us.

Here is the image of the sea floor canyon Starla Robinson, a Senior Survey Technician, and I discovered. We decided it should be named Denla Canyon, after the two scientists who discovered it.

Here I am, gathering pings.

Here I am talking with "the bridge,"  the team responsible for navigating the ship while surveyors collect data.

While collecting data, I kept in contact with “the bridge,” the team responsible for navigating the ship, by radio to ensure the ship’s safety and maximum, quality data acquisition.     Photo by Starla Robinson

 

Step 3, we take into consideration the tide’s effect on the depth of the water.  Tides are one predictable influence on water depth. There are over 38 factors or “constituents” that influence the tides.  The gravitational pull of the sun and the moon at various times of the day, the tilt of the earth, the topography, and many other factors cause water to predictably bulge in different places on earth at different times. The Rainier crew works 24 hours a day and 7 days a week, so they must find a way to measure depth throughout the days and month, by taking into account the tide. Arthur Doodson, who was profoundly deaf, invented the Doodson Numbers a system taking into account the factors influencing tide in 1921. Flash forward to the 21st century, our Commanding Officer, Commander Rick Brennan worked with a team of NOAA scientists to develop a software program called TCARI, as an alternate method to do tide adjustments, taking into account 38 factors, even the moon’s wobble. Inventions abound at NOAA.

The Rainier crew worked for 14 hours today to set up a tide gauge station, an in depth study of how the tide affects our survey area.  On this map, there is a Red X for each tide gauge we will install.  This process only happens at the beginning of the season, and I feel fortunate to have been here–the work we did was….amazing.

 

Each Red X is approximately where a tide gauge will be installed.  The one we installed today in Diver's Bay is in the north west corner of the sheet map.

Each Red X is approximately where a tide gauge will be installed. The one we installed today in Driver Bay is in the north west corner of the sheet map.

You can see an animation here that shows the combined effect of two sine waves that produce a signal like our tide data.  Just imagine what it looks like when you factor in 38 different variables.

The earth goes around the sun in 24 hours and moon goes around the earth in a little more than 12 hours, much like these two gray sine waves. Interestingly, when you add two different waves, you get the wonky blue sine wave, with ups and downs. This combined effect of the sun and the moon (two dots) causes the ups and downs of the tide (blue wave). Graph taken from Russell, D. Acoustics and Vibration Animation, PSU, http://www.acs.psu.edu/drussell/demos/superposition/superposition.html.

 

Low tide is the best time to see sea stars, mussels and barnacles, but it is also a more hazardous time in the tidal cycle for mariners to travel. Therefore, navigational charts use the mean lower low water level, low tide, for the soundings, or depth measurements on a chart.  The black numbers seen on a nautical chart, or soundings, represent depth measurements relative to mean lower low tide. Driver Bay, the area on the chart where we installed the tide gauge today, is the crescent shaped bay at the northwest end of Raspberry Island.

This is a nautical chart used to help mariners navigate safely.

This is a nautical chart used to help mariners navigate safely.

Installing Tide Gauge Stations

Before gathering sonar data, ground and boat crews install a tide gauge to measure changes in water level and to determine the mean lower low water level datum. A tide gauge is a neat device that has air pumped into it, and uses air pressure, to determine how deep the water is.   The tide gauge uses a formula of (density of sea water)(gravity)(height) = pressure.  The gauge measures pressure, and we apply factors for gravity and sea water.  The only missing factor is height, which is what we learn as the gauge collects data.  This formula and nuances for particular locations is a fascinating topic for a blog or master’s thesis.  Scientists are looking for tidal fluctuations and other location specific variances. Then, by computer they determine the mean lower low tide depth, factoring in the tidal fluctuations.

There are permanent tide gauge stations all over the world.  The nearest permanent tide gauge station to our study area is in Kodiak and Seldovia.  These permanent gauges take into account many factors that affect tides over a 19 year period of time, not just the gravitational pull of the moon.

The tide gauge stays in place for at least 28 days (one full tidal cycle).  During the month, data of the tides is collected and can be compared to the other tide gauges we install.

Installing the Tide Gauges and Benchmarks

Excitement built as the crew prepared for the “Tide Party,” packing suitcases full of gear and readying the launches.  Installing Tide Gauges signals the beginning of the season and is one of the few times crew gets paid to go on shore.

 

Why Bench Mark?

There are three reasons I have figured out after many discussions with patient NOAA crew as to why we put in bench marks.

 

I installed this benchmark by having a hole drilled in bedrock and affixing the benchmark with concrete if anyone ever returns and needs to know their exact location.

I installed this benchmark in Driver Cove by having a hole drilled in bedrock and affixing the benchmark with concrete if anyone ever returns and needs to know their exact location. Photo by Barry Jackson

The first reason we install benchmarks is to provide a reference framework to ensure both our tide staff and the tide gauge orifice are stable and not moving relative to land.  The second reason is if we ever come back here again to gather or compare data to previous years, we will know the elevation of the tidal datum at this location relative to these benchmarks and can easily install a new tide gauge.  The third reason is that the earth and ocean floor changes constantly.  As scientists, we need to make sure the survey area is “geologically stable.”  We acquire several hours of GPS measurements on the primary benchmark to measure both its horizontal and vertical position relative to the earth’s  reference frame.  Should there ever be an earthquake here, we can come back afterwards and measure that benchmark again and see how much the position of the Earth’s crust has changed.  After the last big earthquake in Alaska, benchmarks were found to move in excess of a meter in some locations!

Teacher on Land Polishing Her Benchmark Photo by Brandy Geiger

Teacher on Land
Polishing Her Benchmark
Photo by Brandy Geiger

Installing the Benchmark

Today, our beach party broke into two groups.  We located stable places, at about 200 foot intervals along the coastline.  We drilled 5 holes on land and filled them with concrete.  A benchmark is a permanent marker you may have seen at landmarks such as a mountain peak or jetty that will remain in place for 100 years or more.  We stamped the benchmark by hand with a hammer and letter stamps with our station identification.   If we chose a good stable spot, the benchmark should remain in the same location as it is now.

Tide Gauge

As one group sets up benchmarks, another group installed the tide gauge.

 

Here, Chief Jim Jacobson, Lead Survey Technician, sets up a staff, or meter stick, I used to measure the change in water depth and others used for leveling.

Here, Chief Jim Jacobson, Lead Survey Technician, sets up a staff, or meter stick, I used to measure the change in water depth and others used for leveling.  Photo by Barry Jackson

To install the tide gauge, you must have at least three approved divers who install the sensor in deep water so that it is always covered by water.  Because there were only two crew on board trained to dive, Lieutenant Bart Buesseler, who is a dive master, was called in to assist the team.   The dive team secured a sensor below the water.  The sensor measures the water depth with an air pressure valve for at least 28 days.  During this time there is a pump on shore that keeps the tube to the orifice pressurized and a pressure sensor in the gauge that records the pressure. The pressure is equal to the number of feet of sea water vertically above the gauge’s orifice. An on-board data logger records this data and will transmit the data to shore through a satellite antenna.

Divers install the tide gauge, and spent most of the day in the cold Alaska waters.  Good thing they were wearing dive suits!  Photo by Barry Jackson

Divers install the tide gauge, and spent most of the day in the cold Alaska waters. Good thing they were wearing dive suits! Photo by Barry Jackson

Leveling Run

After the gauge and benchmarks are in place, a group does a leveling run to measure the benchmark’s height relative to the staff or meter stick.  One person reads the height difference between 5 different benchmarks and the gauge. Then they go back and measure the height difference a second time to “close” the deal.  They will do the same measurements again at the end of the survey in the fall to make sure the survey area has not changed geographically more than ½ a millimeter in height!  Putting the bubble in the middle of the circle and holding it steady, leveling, was a highlight of my day.

Observation

Finally, a person–me– watches the staff (big meter stick above the sensor) and takes measurements of the water level with their eyes every six minutes for three hours.  Meanwhile, the sensor, secured at the orifice to the ocean floor by divers, is also measuring the water level by pressure. The difference between these two numbers is used to determine how far below the water’s surface the orifice has been installed and to relate that distance to the benchmarks we have just leveled to.  If the numbers are consistent, then we know we have reliable measurements.  I won’t find out if they match until tomorrow, but hope they do.  If they don’t match, I’ll have to go back to Driver Bay and try again.

As we finished up the observations, we had a very exciting sunset exit from Raspberry Island.  I was sad to leave such a beautiful place, but glad to have the memories.

Last minute update: word just came back from my supervisor, Ensign J.C. Clark, that my tidal data matches the gauge’s tidal data, which he says is “proof of my awesomeness.” Anyone who can swim with a car battery in tow is pretty awesome in my book too.

The data Starla Robinson and I collected is represented by the red line and the data the gauge collected is represented by the blue line.  The exact measurements we collected are on the table.

The data Starla Robinson and I collected is represented by the red line and the data the gauge collected is represented by the blue line. The exact measurements we collected are on the table.

Spotlight on a Scientist

Lieutenant Bart Buesseler came to us straight from his family home in the Netherlands, and before that from his research vessel, Bay Hydro II.  The main reason our CO asked him to leave his crew in Chesapeake Bay, Maryland, and join us on the Rainier is because he is a dive master, capable of installing our sensors under water, and gifted at training junior officers.

 

Lieutenant Beusseler knows he needs to be particularly nice to  Floyd Pounds, an amazing cook from the south who cooks food from every corner of our ocean planet.

Lieutenant Beusseler knows he needs to be particularly nice to the amazing chefs aboard Rainier, including Floyd Pounds, who cooks food from every corner of our ocean planet with a hint of a southern accent.

During his few years of service, LTJG Buesseler adventured through the Panama Canal, along both coasts of North America, and has done everything from repairing gear to navigating the largest and smallest of NOAA vessels through very narrow straits.  He loves the variety: “if I get tired of one task, I rotate on to another to keep engaged and keep my mind sharp.”  He explains that on a ship, each person is trained to do most tasks.  For example, he says, “during our fast rescue boat training today, Cal led several rotations. But what if he is gone? Everyone needs to be ready to help in a rescue.”  Bart says at NOAA people educate each other, regardless of their assignments, “cultivating information” among themselves. Everyone is skilled at everything aboard Rainier.
In the end, he says that all the things the crew does are with an end goal of making a chart.   His motto? Do what you love to do and that is what he’s doing.

Personal Log

Today was a special day for me for many reasons.  It is majestic here: the stark Alaskan peninsula white against the changing color of the sky, Raspberry Island with its brown, golden, crimson and forest green vegetation, waterfalls and rocky outcroppings.  I’m seeing whales, Puffins, Harlequin Ducks and got up close with the biggest red fox ever.  Most importantly, I felt useful and simultaneously centered myself by doing tide observations, leveling and hiking.  I almost dove through the surf to make it “home” to the ship just in time for a hot shower. Lieutenant Buesseler’s reference to “cultivating information” rings very true to me.  In writing these blogs, there is virtually nothing I came up with independently.  All that I have written is a product of the patient instruction of Rainier crew, especially Commander Brennan. Each day I feel more like I am a member of the NOAA crew here in Alaska.