Tag: otter

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Patricia Donahue, August 21, 2008

NOAA Teacher at Sea
Patricia Donahue
Onboard NOAA Ship Rainier 
August 19-23, 2008

Mission: Hydrographic Survey of Bear Cove, AK
Geographical Area: Kachemak Bay, Alaska, 59.43.7 N, 151.02.9 W
Date: August 21, 2008

Weather Data from the Bridge at 1000 hours 
Broken clouds (7/8)
Visibility 11 to 27 nautical miles
Winds calm
Seas 0-1 ft (light breeze) at 9.4˚C
Air pressure 1001.5 millibars and rising slightly
Dry Bulb 12.2˚C, Wet Bulb 11.1˚C
Cumulus clouds between 3000 and 5000 feet

The lines circled in red are the track that the boat follows back and forth in order scan the bottom of the sea. It’s a lot like mowing a lawn!
The track that the boat follows back and forth in order scan the bottom of the sea. It’s a lot like mowing a lawn!

Science and Technology Log 

We are anchored in Halibut Cove near a large lagoon too shallow even for the small boats to enter. The nearby mountains have attracted my attention. According to the chart for this area, the two seen off the bow are both 3600 feet high. They have some patches of snow on them. A taller mountain, 4200 feet high, is barely visible in the distance. Nearer the shore some cliffs show evidence of an interesting geological history. Once upon a time, marine sediments collected at the bottom of the sea. The layers built steadily one atop the other, creating organic and clastic sedimentary rocks. The rocks were uplifted to nearly vertical and have eroded. The lighter colored section appears to be limestone but it’s difficult to tell from afar. Due to intense tectonic activity in the area, some of the rock was heated and crushed, causing metamorphism. The section next to what I think is limestone looks to be either a metamorphosed limestone or a batholith. I’m hopeful that someone on board knows more geology than I do!

One of these scans shows a school of fish and the other shows a mound on the sea floor. Can you guess which is which? (Answer: the scan on the left is a mound on the sea floor and the scan on the right is a school of fish.)
One of these scans shows a school of fish and the other shows a mound on the sea floor. Can you guess which is which?

Today I went out on one of the small vessels conducting single beam sonar scanning to determine the depth and shape of the bay bottom. The boat moves across the surface of the sea in straight, parallel lines much like the ones made when cutting the grass with a lawn mower. The lines in the first picture are the rows that the boat “mows.” The sonar pings go down from the bottom of the boat at a rate of 100 per second! The equipment on board measures how much time passes until the ping returns from the bottom. The longer it takes for the sound signal to bounce back, the deeper the water is in that location. The boat also has another scanner similar to what fishermen use to find schools of fish. Look at these two photographs from the scanner. Which is a school of fish and which is a 27 foot high mound on the ocean floor? The depth of the water is in large numbers in the lower left. The numbers farthest to the right are the ocean temperatures. Why is the water colder where the bottom is deeper?

This is a sea otter feasting on a clam! The tiny white spec on its belly is the clam
This is a sea otter feasting on a clam! The tiny white spec on its belly is the clam

Personal Log 

The screen above with the “mowing the lawn” lines on it clearly shows an airplane making its way back and forth. Of course I had to ask, “Why an airplane icon”? I thought they’d tell me that it was for laughs but no, there is a good reason. The airplane icon’s nose keeps in sync with the GPS and the lines better than the ship icon! The surveyors find it easier to know their position.

Animals Seen Today 

  • Many sea otters – Look closely at the picture to the left. The otter in the picture is eating clam. A shell is balanced on its belly!
  • Schools of fish under the boat “seen” by the radar
  • Several types of birds too far away to identify

Vocabulary of the Day 

While inputting the weather this morning, I noticed several screens that we did not add data to and rather than skip them, I decided to see what they were about. They were about ice conditions that a ship might encounter and include in a weather report. Here are two new words I didn’t have for ice. A bergy bit is a large piece of floating glacier ice between 100 and 300 square meters in area and showing less than 5 meters but more than 1 meter above sea level. A growler is smaller than a bergy bit. It is larger than 20 square meters in area but less than 1 meter is above the sea surface. Growlers can be transparent, green, or even black in appearance. Since its summer in Alaska, I won’t be seeing any bergy bits or growlers! I also learned that the term iceberg has a precise definition. An iceberg is a piece of ice afloat or aground that shows more than 5 meters above the sea surface. They are described more specifically by their shape.

Challenge Yourself 

Kachemak Bay receives a lot of glacial melt water. Surveyors have a difficult time with the radar equipment when they encounter freshwater because the sound waves travel at a different speed through fresh water than they do through salt water. In which type of water, salt or fresh, does sound travel faster? Why?

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Patricia Donahue, August 19, 2008

NOAA Teacher at Sea
Patricia Donahue
Onboard NOAA Ship Rainier 
August 19-23, 2008

Mission: Hydrographic Survey of Bear Cove, AK
Geographical Area: Kachemak Bay, Alaska, 59.43.7 N, 151.02.9 W
Date: August 19, 2008

Weather Data from the Bridge at 1600 hours 
Broken clouds (5/8)
Visibility 11 to 27 nautical miles
Winds 230˚ at 6 knots
Seas 0-1 ft (light breeze) at 8.3˚C
Air pressure 1003.5 millibars and falling slightly
Dry Bulb 13.1˚C, Wet Bulb 12˚C
Cumulus and cirrus clouds between 2000 and 3300 feet

Science and Technology Log 

Today I recorded the temperature twice, once in the morning and once in the afternoon. The data is written on a sheet and then entered into a specialized computer program. Once saved, the floppy containing the data is placed in a transmitter for delivery via satellite to the National Weather Service. There are few weather stations in the area so the ship is acting as one! The information will then show up on maps as a station model such as the one shown above. My students learn how to code and decode these models and it was awesome to see where the data comes from and how it is delivered.

This is a weather map symbol that shows wind direction (the arm extending from the circle) from the southwest; wind speed (the smaller arm) at 6 knots; temperature at 13.1˚C; dew point and 12˚C; pressure at 1003.5 mb; and cloud cover which is indicated by the shaded circle and shows broken clouds, meaning partly cloudy.
This is a weather map symbol that shows wind direction (the arm extending from the circle) from the southwest; wind speed (the smaller arm) at 6 knots; temperature at 13.1˚C; dew point and 12˚C; pressure at 1003.5 mb; and cloud cover which is indicated by the shaded circle and shows broken clouds, meaning partly cloudy.

Yesterday and today I also made note of true north and magnetic north. The difference between them was 17 degrees yesterday and 16 degrees today. In Texas a few weeks ago this difference was about 12 degrees. The officer on the bridge told me that there is a lot of interference that accounts for the larger difference here. I was reminded of what I’ve recently learned about the polarity reversals the Earth has undergone throughout its history. According to scientists, the planet is entering a period in which true north and magnetic north will deviate more and more from one another. I read a book I found in the wardroom about the geology of Alaska and discovered that the area we’re in now is mainly sedimentary rock. Through the “big eyes” on the flying bridge I can see a lot of stratification in the rocks. 

NOAA Ship Rainier
NOAA Ship Rainier

One of the engineers showed me the engine room. I was able to see the freshwater generator system that makes potable water for the ship. Salt water is “flashed” to its boiling point but not 100 degrees Celsius! This evaporation is done at a very low pressure by creating a vacuum of more than 90% so the boiling point of the water is much lower. This saves energy. The water evaporates, leaving behind the salts and other minerals dissolved in it. The water vapor is condensed and stored in a tank for use by the crew. One of the evaporators can make about 130 gallons of water in an hour and the ship has two of them. (If the water intake is not as salty, such as where we are now due to the glacial melt water, then more water can be generated.) There are also two storage tanks, each holding 8,400 gallons for a total of nearly 17,000 gallons.

The ship uses between 2000 and 3000 gallons per day so the amount stored could last for 5 days if necessary. There are only 53 people aboard. I did the math and realized that the crew is using a lot less water than I thought. Generally, an estimate of water use is 150 gallons per person per day. Not only is the crew careful about water use, some salt water replaces freshwater. For example, the toilets use salt water. Another interesting thing about the evaporators is that they use titanium plates. Titanium is very, very expensive! Back home people are stealing catalytic converters out of cars to recover the titanium in them! Since I teach the gas laws, distillation, and the periodic table, I plan to include a lesson about the evaporators.

Personal Log 

Today’s big events were a fire drill and an abandon ship drill. Fortunately I’ve gotten to know the ship fairly well and I was able to get to my assigned muster station in a timely fashion. The newly arrived personnel, myself included, also watched survival videos. Extra survival equipment had to be put away and I volunteered to help. I was able to climb down through hatches into the area where dry goods are stored. I wonder if they’ll let me climb the mast? My fears about seasickness have not been realized due to the fact that we are in very calm water. The bay seems more like a lake! From the ship I can see the Dixon Glacier and the Portlock Glacier. I’m sure they are a lot farther away than they appear! The survey team that went out today reported difficulties in the areas where the glacial runoff enters the bay. I hope I get to go out tomorrow.

Animals Seen Today 

Bald Eagle, Otter

Question of the Day 

How much fresh water is each person aboard the Rainier using in one day?

Challenge Yourself 

Use the internet to find out how many people are aboard a large cruise ship or a large naval vessel. Calculate how many gallons of water they would use. How many freshwater generators would the ship need? How much water would the cruise ship have to store to last for 5 days? Using the station model above, can you determine the relative humidity?