aleutian islands – NOAA Teacher at Sea Blog

July 9, 2019July 12, 2019

Meg Stewart: Aleutian Islands, Bald Eagles, Wildflowers, and Bunkers, July 8, 2019

NOAA Teacher at Sea

Meg Stewart

Aboard NOAA Ship Fairweather

July 8 – 19, 2019

Mission: Cape Newenham Hydrographic Survey

Geographic Area of Cruise: Aleutian Islands, Bering Sea

Date: July 8, 2019

Weather Data from the Bridge
Latitude: 54° 59.104 N
Longitude: 166° 28.938 W
Wind: 21 knots SE
Barometer: 1006.6 mb
Visibility: 10 nautical miles
Temperature: 53° F or 11.5° C
Weather: Partly cloudy, no precipitation

Science and Technology Log

Today, we left the port at Dutch Harbor, Unalaska, Alaska and headed toward Cape Newenham. The mission for the Cape Newenham project is to gather detailed ocean depth data in order to knit together a comprehensive and highly detailed surface chart of the seafloor near Cape Newenham. I will talk about that process in my next post.

A view of Dutch Harbor, Unalaska. The surrounding hills are volcanic, with just a thin layer of soil, and not a tree to be seen.

Dutch Harbor is a small town with a relatively deep port. The Ship Fairweather has a draft of 15.5 feet. “Draft” is the vertical length between the surface of the water and the bottom of the ship, which is called the hull. A ship’s draft determines the minimum depth of water a vessel can safely navigate and dock at a port. However, though the Fairweather has a 15.5 foot draft, the crew prefers a 20 foot depth of water at a port.

Map of Bering Sea — This overview map shows where Dutch Harbor is in relation to Alaska, the Pacific Ocean, the Aleutian Islands, the Aleutian Trench and Russia. The A-B line is shown for the cross sectional line in the next figure. Cape Newenham is out next destination.

Dutch Harbor is part of Unalaska Island, which is one of the string of Aleutian Islands. The Aleutian Islands are part of the notorious Ring of Fire that marks the edge of the Pacific tectonic plate. As the Pacific Plate moves and grinds past some plates (like along the North American Plate at the San Andreas Fault) or pulls away from other plates (like the Antarctic and Nazca plates, creating the East Pacific Ridge) or plunges beneath other plates (like the Philippine and Indian-Australian plates, where we get deep ocean depressions called the Mariana Trench and Tonga Trench, respectively), we see active volcanism (which is the “fire”) but also lots of earthquakes. The Aleutian Islands are volcanic in origin – the island chain is a volcanic arc – and are a result of oceanic crust of the Pacific Plate being subducted under the oceanic crust of the North American plate. The deep depression at this tectonic boundary – also called a subduction zone – is called the Aleutian Trench.

Referring to the A-B line shown in the overview map above, this cross section shows the mechanics of the subduction zone at the Aleutian Trench at Unalaska Island.

Aleutian Trench tectonic map — This is a tectonic map of the Aleutian Trench area (the symbol shown as a dark black curved line indicates a subduction zone). The map shows the relative motion of the Pacific and North American plates. It is clipped from the New York State Earth Science Reference Table

Looking at a schematic drawing of the side-view, or cross section, of the Aleutian subduction zone, we can visualize what this looks like beneath the surface. The older and more dense oceanic crust of the Pacific Plate is plunging under the younger oceanic crust of the North American Plate – the more dense material sinks down or subducts – and the less dense material stays floating on top, and this process is all due to gravity. With time, as the oceanic material is drawn deeper into the subduction zone, it becomes hotter, starts to melt and then comes back up to the surface as volcanic material and a string of volcanoes forming parallel – and in this case, forming an arc – to the boundary between the Pacific Plate and the North American Plate.

Personal Log

Arriving at NOAA Ship Fairweather — Arriving at NOAA Ship *Fairweather*

I arrived at Dutch Harbor on July 6, after 14 hours and three legs of air travel. Fortunately, I made all my connections and my luggage arrived at the tiny Dutch Harbor airport. I was picked up by welcome smile for a nice person from the Ship Fairweather, got to the port and settled in to my stateroom. The “stateroom” is my sleeping quarters or room. I have it all to myself, it is very comfortable with a sink, a small bed, drawers and a closet to fit all my stuff, and there’s a TV that I haven’t yet figured out how to work.

My stateroom or sleeping quarters. Caution: panoramic photos make everything look larger than they really are.

Did You Know?

On my second day in Dutch Harbor, I went out with some new friends from the ship on a lovely hike on nearby Bunker Hill. I saw so many beautiful wildflowers along the trek and an enormous number of bald eagles. I had no idea that bald eagles would be so plentiful here, but they were everywhere. It was amazing! But the other interesting thing about this hike were the bunkers. In June 1942, Dutch Harbor was bombed by the Japanese Navy (six months after Pearl Harbor) during World War II. At the time of the raid, Alaska was a U.S. territory, and following the bombing, the bunkers of the now-known-as Bunker Hill were built to help defend not only Alaska but the west coast of mainland U.S. And here I thought Dutch Harbor was only known for Deadliest Catch!

Our hiking crew being watched with eagle eyes.
So many different wildflowers and I still forgot to get a photo of the lupines.
An intact WWII bunker on the top of Bunker Hill.
A T-shirt spotted at the local grocery store.

Quote of the Day

“Even if you never have the chance to see or touch the ocean, the ocean touches you with every breath you take, every drop of water you drink, every bite you consume. Everyone, everywhere is inextricably connected to and utterly dependent upon the existence of the sea.” Sylvia Earle

August 16, 2018August 16, 2018

Tom Savage: The Physical Geography of the Aleutian Islands, August 16, 2015

NOAA Teacher at Sea

Tom Savage

Aboard NOAA Ship Fairweather

August 6 – 23, 2018

Mission: Arctic Access Hydrographic Survey

Geographic Area of Cruise: Point Hope, northwest Alaska

Date: August 16, 2018

Weather Data from the Bridge

Latitude 68 38.8 N
Longitude – 166 23.8 W
Air temperature: 10 C
Dry bulb 10 C
Wet bulb 8.9 C
Visibility: 8 Nautical Miles (8.8 miles)
Wind speed: 26 knots
Wind direction: east
Barometer: 1007 millibars
Cloud Height: 2 K feet
Waves: 6 feet

Sunrise: 6:33 am
Sunset: 11:51 pm

Physical Geography of Aleutian Islands

The Aleutian Islands are a product of a subduction zone between the North American and the Pacific Plate and known as the Aleutian Arc. Along this boundary, the Pacific Plate is being subducted underneath the North American Plate due to the difference in density. As a result, the plate heats up, melts and forms volcanoes. In this case the islands are classified as volcanic arcs. As a result of this collision, along the boundary the Aleutian Trench was formed and the deepest section measures 25,663 ft! For comparison purposes, the deepest point in the ocean is located in the Mariana’s Trench at 36,070 feet (6.8 miles)! Through the use of radioisotopic dating of basalt rocks throughout the Aleutians, geologists have concluded the formation of the island chain occurred 35 million years ago. (USGS). Today, there are 14 volcanic islands and an additional 55 smaller islands making up the island chain.

ConvergentBoundary — The Aleutian Islands – yellow line indicates subduction boundary (Courtesy of US Geologic Survey)

On the map above, the Aleutian Islands appear small. However, they extend an area of 6,821 sq mi and extend out to 1,200 miles! In comparison, North Carolina from the westernmost point to the Outer Banks is 560 miles, half of the Aleutian Islands. It takes roughly ten hours to drive from Murphy NC (western NC) to the Outer Banks of North Carolina. Since this region of the North American plate and the Pacific Plate are both oceanic plates, Island Arcs are formed. This is the same classification as the Bahamas, located southeast of Florida.

Convergence of North American and Pacific Plates – Image courtesy of US Geologic Survey

Oceanic-OceanicPlate — Convergence of two Oceanic Plate – Image courtesy of US Geologic Survey

The image above depicts a cross section of the geological forces that shaped the Aleutian Islands. As the two plates collide, the oceanic crust is subducted under the lithosphere further offshore thus generating the island arcs. Unlike the west coasts of Washington, Oregon and California, there is an oceanic/continental collision of plates resulting in the formation of volcanoes further on the continental crust, hundreds of miles inland. Examples are Mount Rainier, Mount Hood, and Mount St. Helen’s which erupted in 1980.

Alpine Glaciers are prevalent throughout the mountainous region of Alaska. What about the Aleutians Islands? Today there are a few small alpine glaciers existing on Aleutian Islands. Alpine glacier on the Attu Island is one example, which is the western most island.

Personal Log

One truth about being at sea is don’t trust the wall, floor or ceiling. Sometimes, the wall will become the floor or the ceiling will become the wall 🙂 Lately, the seas have become this ongoing amusement park ride. Although the weather has been a bit rough, data collection continues with the ship. The weather outside is more reflective of fall and winter back in North Carolina, though we have not seen any snow flakes. After surfing the waves yesterday while collecting data, today the hydrographers are processing data collected over the past few days.

Yesterday was whale day! Early afternoon, humpbacks were spotted from the port side of the ship (left side). As the afternoon went on, humpbacks were spotted all around the Fairweather, at distances of 0.5 miles to 5 miles. Humpbacks are considered the “Clowns of the Seas” according to many marine biologists. Identifying whales can be tricky especially if they are distances greater than a few miles. Humpbacks are famous for breaching the water and putting on a show, Yesterday we did not witness this behavior, however they were showing off their beautiful flukes.

Humpback whale fluke, photo courtesy of NOAA

Question of the Day: Which whale species, when surfacing, generates a v shape blow?

Until next time, happy sailing!

Tom

August 7, 2014August 21, 2021

Gregory Cook, The Dance, August 7, 2014

NOAA Teacher at Sea

Gregory Cook

Aboard NOAA Ship Oscar Dyson

July 26 – August 13, 2014

Mission: Annual Walleye Pollock Survey

Geographical Area: Bering Sea

Date: August 7, 2014

Science and Technology Log: Abiotic Factors in the Bering Sea

Ecosystems are made up of biotic and abiotic factors. Biotic is just another word for “stuff that is, or was, alive.” In a forest, that would include everything from Owl to Oak Tree, from bear to bacteria, and from fish to fungi. It includes anything alive, or, for that matter, dead. Keep in mind that “dead” is not the same as “non-living.”

Salmon and Black-Legged Kittiwake — The salmon and the black-legged kittiwake are both biotic members of the sub-arctic ecosystem.

“Non-living” describes things that are not, cannot, and never will be “alive.” These things are referred to as “abiotic.” (The prefix a- basically means the same as non-). Rocks, water, wind, sunlight and temperature are all considered abiotic factors. And while the most obvious threat to a salmon swimming up river might be the slash of a bear’s mighty claw, warm water could be even more deadly. Warm water carries less dissolved oxygen for the fish to absorb through their gills. This means that a power plant or factory that releases warm water into a river could actually cause fish to suffocate and, well, drown.

Bering Panorama — A 90 degree panorama of the Bering Sea from atop the Oscar Dyson. I’d show you the other 270°, but it’s pretty much the same. The sea and sky are abiotic parts of the sub-arctic ecosystem.

Fish in the Bering Sea have the same kind of challenges. Like Goldilocks, Pollock are always looking for sea water that is just right. The Oscar Dyson has the tools for testing all sorts of Abiotic factors. This is the Conductivity Temperature Depth sensor (Also known as the CTD).

CTD Deployment — Survey Technicians Allen and Bill teach me how to launch The Conductivity Temperature Depth Probe (or CTD).

The CTD sends signals up to computers in the cave to explain all sorts of abiotic conditions in the water column. It can measure how salty the water is by testing how well the water conducts electricity. It can tell you how cloudy, or turbid, the water is with a turbidity sensor. It can even tell you things like the amount of oxygen dissolved in the ocean.

To see how abiotic factors drive biotic factors, take a look at this.

I know, you may want to turn the graph above on its side… but don’t. You’ll notice that depth is on the y-axis (left). That means that the further down you are on the graph, the deeper in the sea you are. The blue line represents the water temperature at that depth. Where do you see the temperature drop?

Right… The temperature drops rapidly between about 20 and 35 meters. This part of the water column is called the Thermocline, and you’ll find it in much of the world’s oceans. It’s essentially where the temperature between surface waters (which are heated by the sun) and the deeper waters (typically dark and cold) mix together.

OK, so you’re like “great. So what? Water gets colder. Big deal… let’s throw a parade for science.”

Well, look at the graph to the right. It was made from another kind of data recorded by the CTD.

Fluoresence: Another depth-oriented graph from the CTD… the green line effectively shows us the amount of phytoplankton in the water column, based on depth.

The green line represents the amount of fluorescence. Fluorescence is a marker of phytoplankton. Phytoplankton are plant-like protists… the great producers of the sea! The more fluorescence, the more phytoplankton you have. Phytoplankton love to live right at the bottom of the thermocline. It gives them the best of both worlds: sunlight from above and nutrients from the bottom of the sea, which so many animals call home.

Now, if you’re a fish… especially a vegetarian fish, you just said: “Dinner? I’m listening…” But there’s an added bonus.

Look at this:

CTD Oxygen — Oxygen data from the CTD! This shows where the most dissolved oxygen is in the water column, based on depth. Notice any connections to the other graphs?

That orange line represents the amount of oxygen dissolved in the water. How does that compare to the other graphs?

Yup! The phytoplankton is hanging down there at the bottom of the thermocline cranking out oxygen! What a fine place to be a fish! Dinner and plenty of fresh air to breathe! So here, the abiotic (the temperature) drives the biotic (phytoplankton) which then drives the abiotic again (oxygen). This dance between biotic and abiotic plays out throughout earth’s ecosystems.

Another major abiotic factor is the depth of the ocean floor. Deep areas, also known as abyss, or abyssal plains, have food sources that are so far below the surface that phytoplankton can’t take advantage of the ground nutrients. Bad for phytoplankton is, of course, bad for fish. Look at this:

The Cliff and the Cod — The blue cloud represents a last grouping of fish as the continental shelf drops into the deep. Dr. Mikhail examines a cod.

That sloping red line is the profile (side view of the shape of the land) of the ocean floor. Those blue dots on the slope are fish. As Dr. Mikhail Stepanenko, a visiting Pollock specialist from Vladivostok, Russia, puts it, “after this… no more Pollock. It’s too deep.”

He goes on to show me how Pollock in the Bering Sea are only found on the continental shelf between the Aleutian Islands and Northeastern Russia. Young Pollock start their lives down near the Aleutians to the southeast, then migrate Northwest towards Russia, where lots of food is waiting for them.

Pollock Distribution — Alaskan Pollock avoid the deep! Purple line represents the ocean floor right before it drops off into the Aleutian Basin… a very deep place!

The purple line drawn in represents the drop-off you saw above… right before the deep zone. Pollock tend to stay in the shallow areas above it… where the eating is good!

Once again, the dance between the abiotic and the biotic create an ecosystem. Over the abyss, Phytoplankton can’t take advantage of nutrients from the deep, and fish can’t take advantage of the phytoplankton. Nonliving aspects have a MASSIVE impact on all the organisms in an ecosystem.

Next time we explore the Biotic side of things… the Sub-arctic food web!

Personal Log: The Order of the Monkey’s Fist.

Sweet William, a retired police officer turned ship’s engineer, tells the story of the order of the monkey’s fist.

William and the Monkey's Fist — Sweet William the Engineer shows off a monkey’s fist

The story goes that some island came up with a clever way to catch monkeys. They’d place a piece of fruit in a jar just barely big enough for the fruit to fit through and then leave the jar out for the monkeys. When a monkey saw it, they’d reach their hand in to grab the fruit, but couldn’t pull it out because their hands were too big now that they had the fruit in it. The monkey, so attached to the idea of an “easy” meal wouldn’t let go, making them easy pickings for the islanders. The Monkey’s Fist became a symbol for how clinging to our desires for some things can, in the end, do more harm than good. That sometimes letting go of something we want so badly is, in the end, what can grant us relief.

Another story of the origin of the monkey’s fist goes like this: A sea captain saw a sailor on the beach sharing his meal with a monkey. Without skipping a beat, the monkey went into the jungle and brought the sailor some of HIS meal… a piece of fruit.

No man is an Island. Mt. Ballyhoo, Unalaska, AK

Whatever the true origin of the Order is, the message is the same. Generosity beats selfishness at sea. It’s often better to let go of your own interests, sometimes, and think of someone else’s. Onboard the Oscar Dyson, when we see someone committing an act of kindness, we put their name in a box. Every now and then they pull a name from the box, and that person wins something at the ship store… a hat or a t-shirt or what have you. Of course, that’s not the point. The point is that NOAA sailors… scientists, corps, and crew… have each other’s backs. They look out for each other in a place where all they really have IS each other.

And that’s a beautiful thing.

May 6, 2013August 11, 2021

Frank Hubacz: ADCP Deployment, May 2, 2013

NOAA Teacher at Sea
Frank Hubacz
Aboard NOAA ship Oscar Dyson
April 29 – May 10, 2013

Mission: Pacific Marine Environmental Laboratory Mooring Deployment and Recovery
Geographical Area of Cruise: Gulf of Alaska and the Bering Sea
Date: May 2, 2013

Weather Data from the Bridge:

Partly sunny, WindsN 5-10 knots
Air Temperature 1.3C

Relative Humidity 60%

Barometer 1008.2 mb

Surface Water Temperature 2.8C

Surface Water Salinity 31.37 PSU

Science and Technology Log

As I described previously, one of the instruments being deployed on this cruise is an Acoustic Doppler Current Profiler (ADCP), which measures speed and direction of ocean currents across an entire water column using the principle of Doppler shift (effect). The Doppler Effect is best illustrated when you stop and listen to the whistle of an oncoming train. When the train is traveling towards you, the whistle’s pitch is higher. When it is moving away from you, the pitch is lower. The change in pitch is proportional to the speed of the train. The diagrams below illustrates the effect.

: Another view of the Doppler Effect

The ADCP exploits the Doppler Effect by emitting a sequence of high frequency pulses of sound (“pings”) that scatter off of moving particles in the water. Depending on whether the particles are moving toward or away from the sound source, the frequency of the return signal bounced back to the ADCP is either higher or lower. Since the particles move at the same speed as the water that carries them, the frequency shift is proportional to the speed of the water, or current.

The ADCP has 4 acoustic transducers that emit and receive acoustical pulses from 4 different directions. Current direction is computed by using trigonometric relations to convert the return signal from the 4 transducers to ‘earth’ coordinates (north-south, east-west and up-down. (http://oceanexplorer.noaa.gov/technology/tools/acoust_doppler/acoust_doppler.html). The most common frequencies used on these units are 600 KHz, 300 KHz, and 75 KHz. The lower the frequency the greater the distance that the wave can propagate through the ocean waters.

Determining current flow helps scientist to understand how nutrients and other chemical species are transported throughout the ocean.

Typical 4 beam ADCP sensor head. The red circles denote the 4 transducer faces.

Prior to sailing, ADCP mooring locations are selected by various research scientists from within NOAA. Next, engineers develop a construction plan to secure the unit onto the ocean floor. Once designed, the hardware needed to construct the mooring is sent to the ship that will be sailing in the selected mooring locations. Prior to arriving at the designated location it is the responsibility of the science team to construct the mooring setup following the engineering diagram shipped with each ADCP unit. ADCP moorings can be constructed to hold a wide variety of measuring instruments depending upon the ocean parameters under study by the research scientist.

The moorings are built on the ship’s deck starting with an anchor. The anchor weight is determined based upon known current strength in the area where the mooring will be located. Anchors are simply scrap iron railroad train car wheels which bury themselves into the sediment and eventually rust away after use. The first mooring unit that we assembled had an anchor composed of two train wheels with a total weight of 1,600lbs. Although this mooring was built from the anchor up this is not always the case. When setting very deep moorings the build is in the reverse order.

Anchor on the back deck below the gantry

Next, an acoustic release mechanism is attached to the anchor by way of heavy chains. This mechanism allows for recovery of the ADCP unit as well as the release mechanism itself when it is time to recover the ADCP. The units that we are deploying will remain submerged and collect data for approximately 6 months.

: Acoustic Release Mechanism

Bill attaching the acoustic release mechanism

Finally, an orange closed-cell foam and stainless steel frame containing the actual instrumentation is connected to the assembly and then craned over the back deck. The stainless steel frame has a block of zinc attached to it which acts as a sacrificial anode. Sacrificial anodes are highly active metals (such as zinc) that are used to prevent a less active metal surface from rusting or corroding away. In fact, our ship has many such anodes located on its hull. Once the entire unit is in position, a pin connected to a long chord is pulled from a release mechanism and the unit is dropped to the ocean floor. Date, time, and location for each unit are then recorded.

To recover the unit, an acoustic signal (9-12 Khz) is sent to the ship from the sunken mooring unit to aid in its location. Once located, a signal is used to activate a remote sensor which powers the release mechanism to open. The float unit then rises to the surface bringing all of its attached instruments along with it. The stored data within the units are then secured and eventually sent along to the research scientist requesting that specific mooring location for ocean current analysis.

Personal Log

On my first day of “work” I was able to watch the science teams deploy three different ADCP moorings as well as conduct several CTD runs. I will discuss CTD’s in more detail in future blogs. I was impressed by the camaraderie among all of the science team members regardless of the institution that they represented as well as with members of the deck crew. They all work as a very cohesive and efficient group and certainly understand the importance of teamwork!

Adjusting to my new work schedule is a bit of a challenge. After my work day ended today at 1200 hours, I fell asleep around 1500 hours for about 4 hours. After trying to fall back asleep again, but to no avail, I decided to have a “midnight” snack at 2000 hours (8pm). I finally fell asleep for about 2 more hours before showering for my next shift. I think I now have more empathy for students who come to my 8am chemistry class and occasionally “nap”!

A wide selection of food is always available in the ship’s galley. I have discovered that I am not the only one taking advantage of this “benefit”! I will definitely need to reestablish an exercise routine when I return home. We are currently heading for Unimak Pass which is a wide strait between the Bering Sea and the North Pacific Ocean southwest of Unimak Island in the Aleutian Islands of Alaska.

Did you know that since the island chain crosses longitude 180°, the Aleutian Islands contain both the westernmost and easternmost points in the United States. (172° E and 163° W)!

June 21, 2011April 28, 2021

Tammy Orilio, My First Pollock Trawl, June 20, 2011

NOAA Teacher at Sea: Tammy Orilio

NOAA Ship Oscar Dyson

Mission: Pollock Survey

Geographical Area of Cruise: Gulf of Alaska

Date: 20 June 2011

Weather Data from the Bridge:

Latitude: 54.29 N

Longitude: -165.13 W

Wind Speed: 12.31 knots

Surface Water Temp: 5.5 degrees C

Water Depth: 140.99 m

Air Temp: 6.1 degrees C

Relative Humidity: 97%

Science & Technology Log: walleye pollock, which is an important fish species here in Alaska. Walleye pollock make up 56.3% of the groundfish catch in Alaska (http://www.afsc.noaa.gov/species/pollock.php), and chances are you’ve eaten it before. It’s a commonly used fish in all of the fast food restaurants, in fish sticks, and it’s also used to make imitation crab meat.

Our first catch had a little over 300 walleye pollock, and we processed all of them. Three hundred is an ideal sample size for this species. If, for example, we had caught 2,000 pollock, we would only have processed 300 of the fish, and we would have released the rest of them back into the ocean. Check out the photos/captions below to see how we process the catch.

Length Station — After sexing, we then measured the length of each fish. There’s a ruler embedded in the lab table, and we laid each fish down on the ruler. Then we put a hand-held sensor at the caudal (tail) fin of the fish, and the total length was recorded on a computer.

At the sexing station, cutting open pollack.

We also removed and preserved 20 stomachs from randomly selected fish in order to (later) analyze what they had been eating prior to them being caught. One of the last things we do is collect otoliths from each of those 20 fish. Otoliths are ear bones, and they are used to determine the age of a fish- they have rings, similar to what you see in trees.

Here’s a look at some of the bycatch in our nets:

Basket Star. Marine 1: What phylum are sea stars in?

The reason(s) WHY they're called ARROWTOOTH flounder. — The reason(s) WHY they’re called ARROWTOOTH flounder.

Animals Spotted:

walleye pollock

chum salmon

rockfish

arrowtooth flounder

squid

basket star

Northern Fulmars

Gulls

Albatross (couldn’t tell what kind)

* I did spot some kind of pinniped yesterday, but have no idea what exactly it was!

Personal Log:

I was very excited that we finally got to fish today!! As an added bonus, we caught 2 salmon in the trawl, which means we’re having salmon for dinner tonight! We we supposed the have teriyaki steak, but the cook has changed it to teriyaki salmon instead 🙂 I didn’t get any pics of them because my gloves were covered in fish scales, blood, and guts by that point and I didn’t want to get any of that funk on my camera 🙂
We passed by Dutch Harbor yesterday- it should sound familiar if you watch Deadliest Catch. We didn’t go into the Harbor, so no, I didn’t see any of the crab boats or any of the guys from the show! Below are some pics of the Aleutian Islands that I’ve see thus far…many more to come, since we still have another 13 days (give or take) of sailing left!

QUESTION(S) OF THE DAY:

The Aleutian Islands were formed at the boundary where the North American and Pacific Plates are coming together. The Pacific Plate is denser than the North American Plate, so it slides underneath the North American Plate. What is this type of plate boundary called (where plates move towards each other), and what is it called when one plate slides underneath another?
One thing we’re doing on this trip is trawling for fish. We are conducting both mid-water and bottom trawls. Describe one advantage and one disadvantage to trawling in order to gather scientific data.