Avery Marvin: Ebbs and Flows and Puffins! July 11, 2013

NOAA Teacher at Sea
Avery Marvin
Aboard NOAA Ship Rainier
July 8 — 25, 2013 

Mission: Hydrographic Survey
Geographical Area of Cruise: Shumagin Islands, Alaska
Date: July 11, 2013

Current Location: 54° 49.6 N, 159° 46.6 W

Weather data from bridge: 8.7°C, good visibility (6-8 miles), light and variable wind, overcast

View of Bird Island Cove from tide gauge installation point
View of Bird Island Cove from tide gauge installation point

Science and Technology Log:

Today, Rosalind and I were scientists in the field, helping the ship’s crew install tidal equipment in preparation for ocean floor survey work.  This was a complex process, so we decided to walk you through it in a step-by-step question format.

What does a navigation chart show you?

The image below shows a chart of the area that we are in right now. Our first anchor point was off the north coast of Bird Island in a cove. On the chart, you can see many tiny numbers in the water areas, which represent various depths.  These depths are measured in fathoms (1 fathom=6 feet).  This depth information helps mariners stay in safe areas that are not too shallow. The charts also show known hazards such as sub-surface rocks and ship-wrecks. This chart clearly has a lot of white space, signifying many areas were never surveyed.

Shumagin survey area
Part of our survey area. Notice the white spaces around Bird and Chernabura Islands!

But wait, why are the depth numbers “fixed” on the charts? Doesn’t the water level change with the tides?

Yes! It sounds easy to say, “the water is 10 fathoms deep at this point”. However, water is subject to the gravitational pull of the moon and sun, resulting in various water levels or tides throughout the day.  So the water will not always be “10 fathoms deep at this point.” For navigational purposes, the most hazardous water level is the lowest one, so nautical charts show the depth at the low tide water level.  Depending on the location, some places have two high tides and two low tides per day (semi-diurnal) and some places have one high tide and one low tide per day (diurnal). Here in the Shumagin Islands we are on a semi-diurnal mixed tide schedule (meaning that the two highs and two lows are not the same height).

How do you measure the tides each day?

Map of the Shumagin Island-Sand Point Tide Zones. Notice how the eastern Shumagin Islands are 6 minutes ahead of Sand Point.

There are permanent tide measuring stations all over the globe that provide information on how to “correct for” and figure out your local tide conditions. For our case, there is a tide station at Sand Point on Popof Island, which is west from our survey area.  Our survey area is in two zones, one which is in the same zone as Sand Point and the other which is in a different zone. Therefore, we installed a tide gauge in the latter to verify that the tidal times and heights of this zone are accurately predicted by the Sand Point values. According to the current information, it says that in the different zone the tides should occur 6 minutes before the tides in Sand Point and to multiply the heights by 0.98.

A tide gauge is a pretty cool device that works by the laws of physics. It is installed (by divers) on the sea floor near a coast-line, in relatively deep water, so that it will always be covered with water. The tide gauge uses the water pressure above to determine the depth of the water column (density of water and gravity are the important factors in making this calculation). The tide gauge stays in place for at least 28 days (one full tidal cycle), after which there is a record of the water level throughout that time period (as we were gathering data), as well as a rough idea of the tidal cycle each month, ready for comparison to the Sand Point data.

How do you know if the tide gauge is working?

To verify that the tide gauge is working, humans (i.e.: Rosalind and I), take water level  measurements (in an area close to the tide gauge) using a giant meter stick or “staff”. In our case, we recorded the average water level height every 6 minutes for 3 consecutive hours.  This 3-hour data set can then be compared to the tide gauge data set for that same time period, and hopefully they will show similar trends.  

Geiger_IMG_1279 (25)
Mike (XO) and Avery, taking water level data using the staff (big meter stick)
Tide staff
This is the tide staff we used to gather water level data for comparison to the tide gauge.
Map of the Shumagin Island-Sand Point Tide Zones. Notice how the eastern Shumagin Islands are 6 minutes ahead of Sand Point.
Graph showing the water height measurements from the tide staff and the tide gauge. Notice how they appear to be increasing at the same rate! That’s good.

What happens if the survey terrain changes over time? Will that affect the water depth?

The ocean floor is above a liquid mantle, so it is possible for there to be terrain changes and this would affect water depth measurements. Thus, as scientists, we must make sure the location of our survey area is “geologically stable”. To do this, we installed “benchmarks”. If you’ve ever been to the highest point on a mountain in the United States, you might have already seen something like this: they are bronze disks that mark important places, used by NOAA as well as other agencies. We stamped our benchmarks with the year and our station data, letter A-E (by hand! with a hammer and letter stamps!), and installed them at roughly 200-foot intervals along the coastline in what we hope is bedrock. Once they were cemented in place, we determined each benchmark’s relative height in relation to the staff using a survey instrument called an optical level – this process is also called “leveling.” At the end of the survey season, the ship will come back and re-level them. If the area is geologically stable, the benchmarks should all be at the same relative heights to one another as they were when they were initially installed. More so, the scientists will also be very pleased because their ocean depth measurements will be reliable going forward in time.

Stamping a benchmark
Stamping a benchmark
Cemented benchmark
A benchmark firmly cemented in place.
Avery cements her first benchmark :)
Avery next to her first cemented benchmark 🙂
Rosalind measuring distance between benchmarks
Rosalind measuring the distance between benchmarks

So what next?

Now that we have completed all necessary pre-survey measurements and research, we are ready to begin surveying the coastline and ocean floor.  Happy Hydro!

Personal log

It’s a pretty cool feeling to know that you stepped foot on an island that hasn’t seen human visitors in 20+ years. It was also refreshing to get off the big boat and head to shore for some science fieldwork. I learned all about tide gauge and benchmark installation.  I had several small but important tasks:

  • stamp each bronze benchmark with year and appropriate code using hammer and metal letter stamps
  • mix up cement batter and add to drilled rock hole and under benchmark disc to secure it in place for years to come (much harder than it looks because the cement was like “oobleck” and not very cooperative)
  • measure distance between each benchmark using extra long tape measure
  • take water level data using staff (big meter stick) in water every 6 minutes
Cool anemome I found!
Cool sea anemone I found!

In between tasks, I perused the tide pools for various critters. I saw a few new anemones and got a great shot of one with my new underwater camera.  I absolutely love tide pooling and could spend most of the day doing it.  I also enjoyed observing the puffins flying in and out of their cliff-side home. They tended to leave the cliff in packs probably to do some offshore fishing for herring and capelin. Upon return, presumably with a belly full of fish, some puffins would fly in large circles near their dwelling a few times before finally landing. This bewildered me. I thought, what a waste of energy! So I researched this and found out the following:  Puffins are much better swimmers than flyers and have poor maneuverability while in the air. They sometimes are involved in mid-air collisions or crash landings into rocky slopes. Thus, they “size up” their landing a few times by circling near it before finally flying directly into their vertical burrow entrance.

Their body is mostly adapted for swimming, with short rigid wings helping them to “fly” underwater, to 30+ ft. depths! They have durable bones that endure pressure changes while diving and their body tissues store oxygen. They use anaerobic respiration for long dives. To waterproof their wings, puffins rub their bill on their oil gland several times and then smear this oil all over their feathers. How cool!

We are seeing a lot of Tufted Puffins out here in the Shumigans because it is breeding season (June-August), the time when they return from lonely open waters to rocky islands to mate and raise young. Puffins are monogamous, usually having one partner for many years. Interestingly, a female puffin only lays one egg, which is incubated for around 45 days! Both parents share incubation and feeding duties. Right on! The chick then stays in the nest for around 45 days until ready to fly. I love puffins! They are not only adorable but very well-adapted creatures.

Tufted Puffin
Tufted Puffin

Fun/sad factoid: Alaskan and Canadian natives made reversible parkas out of puffin skin. When it was rainy out, they wore the feathers on the outside and in cold dry weather, they wore the feathers on the inside. It took 45 puffins to make one parka!

Cathrine Fox: Issue Five: Cuteness factor of eleven

JULY 24 – AUGUST 14, 2011
Personal Log:
I’d like to say that it was for purely scientific reasons that the next cartoon in the series features the Puffins of Alaska. The truth be told, it was their deliciously cute little squishy bodies, their Buddha-like serenity and comical attempts at movement above water. Not sold yet? One viewing of the live “Puffin Cam” on Seal Island National Wildlife Refuge and you will be enraptured…


Adventures in a Blue World, Issue 5
Adventures in a Blue World, Issue 5

Until our next adventure,

Caroline Singler, July,28 – August 1, 2010

NOAA Teacher at Sea: Caroline Singler
Ship: USCGC Healy

Mission: Extended Continental Shelf Survey
Geographical area of cruise: Arctic Ocean

Date of Post: 2 September 2010

The Journey Begins – 28 July to 1 August 2010

Approaching Dutch Harbor
Approaching Dutch Harbor

I left home at 5:30 a.m. on Thursday 28 July for what ended up being nearly 20 hours of travel. At the end of the day, I was exhausted but relieved to have successfully reached my destination, Dutch Harbor, Alaska. The trip from Anchorage to Dutch is 790 miles but required 2 refueling stops along the way and took more than 3 hours. It’s never a sure bet that a plane will be able to land, so we were fortunate to make a safe landing in the rain and wind.

View from Unisea Inn
View from Unisea Inn
While in Dutch Harbor, I stayed at the Unisea Inn. It’s not exactly luxury accomodations,and I couldn’t believe there was actually a hotel there when the shuttle driver dropped me off, but it was clean and there was lots of hot water, and my room looked out over the small boat harbor, which was much nicer than the nearby fish processing plants! I spent the last few days wandering around Dutch Harbor and Unalaska. The cool weather was a welcome relief after the hot, humid summer we’ve had back home. I did have to pull out the rain gear, but while it’s often cloudy, it rarely rains for long. The sky is constantly changing, and as the sky changes, everything around looks different as well. It’s been great to just be out walking around since I will be on a ship for the next 5 weeks. Here’s a view of Dutch Harbor from a hill near town.
View of Dutch Harbor
View of Dutch Harbor
Bald Eagles
Bald Eagles
When I woke up this morning, I realized it was the last time I’d wake up on land for a while. That was a strange feeling. Late this afternoon we boarded the Healy. I unpacked my bags and I’m ready to go, but we don’t leave port until tomorrow afternoon. I’ll post more after I’ve learned more about the ship’s computer system.Caroline

Kathy Virdin, July 21, 2004

NOAA Teacher at Sea
Kathy Virdin
Onboard NOAA Ship Rainier

July 20 – 28, 2004

Mission: Hydrographic Survey
Geographical Area:
Eastern Aleutian Islands, Alaska
July 21, 2004

Time: 6:00p.m.
Latitude: 55 degrees 49.65 N
Longitude: 157 degrees 56 W
Visibility: 11 nautical miles
Wind direction: 350 degrees NW
Wind speed: 7 kts
Sea wave height: 0-1 ft.
Swell wave height:2-3 ft.
Sea water temperature: 12.2 C.
Sea level pressure: 1013.0 mb.
Cloud cover: Partly cloudy

Science and Technology Log

Today I was able to go out on a launch (small boat) that did survey lines for eight hours. After the launch got underway, we lowered the transducer into the water where it will send out a spray of sound (approximately 131 pings) that will be measured on the launch’s computers. We also did a Reson line measurement which can accurately measure depths of 40 meters. We drove the launch in a line that was approximately 4-5 miles long, then turned and went back on the next line. Each line took about 40 minutes and we were able to cover 7 lines today. So in all, we were able to chart an area of 4-5 square miles. We stopped every four hours to put down a CDT which checks salinity, density and temperature. This information was immediately fed into the computers so that it can adjust the speed of sound through the waters by these factors. This launch also has a motion sensor that can measure the pitch and roll of the boat and that is factored into the speed the sound travels, which gives the calculated distance to the ocean floor.

NOAA has about 8 or 9 ships that do hydrography work which is extremely important to scientific research, as well as commerce. About 90-95% of all goods used in the U.S. are brought to us by ships! So it’s vital that they have accurate information to chart their path through our waters. The RAINIER is the only ship in the world that can do all the hydrographic survey work that it does. It’s an honor to work on a NOAA vessel and all members of the NOAA corps must have a degree in one of the sciences. The swath or path of the sonar beam that our launch is sending out covers about 200 meters. We’re seeing the data that tells us that the depths in this area are 100 meters. We have successfully measured our plot of the chart today with multi-beam swaths that intersect at the outskirts with one another. This is another measure taken to ensure accuracy.

Personal Log

I asked a lot of questions today while we were surveying, as the field operations officer with us had time to answer them. The work was mostly being done by the computers, so we were watching and checking them periodically. I learned that the launches are expensive boats because of all the high-tech equipment they carry (all of it necessary to get the job done). When we came back to the RAINIER, the sun came out and we went up on the deck to enjoy the view. I saw puffins flying over the water, and one of them flapped its wings across the water as it skimmed along the surface. This was a treat to watch the puffins as they entertained us with their antics. Tomorrow, I’m looking forward to following up on the data that was gathered from the two launches that went out today. It will be scrutinized and evaluated by the survey technicians and then stored in the folder for the day.