Lona Hall: Land and Sea, June 12, 2019

NOAA Teacher at Sea

Lona Hall

Aboard NOAA Ship Rainier

June 3 – 14, 2019

Mission: Kodiak Island Hydrographic Survey

Geographic Area of Cruise: Kodiak Island, Alaska

Date: June 12, 2019

Time:  1541 hours

Location: Saltery Cove, Kodiak Island

Weather from the Bridge:

Latitude: 57°29.1009’ N

Longitude: 152°44.0031’ W

Wind Speed: 9.0 knots

Wind Direction: N (10 degrees)

Air Temperature: 12.78° Celsius

Water Temperature: 8.89° Celsius

Lona in immersion suit
All dressed up (in an immersion suit) and no place to go

Science and Technology Log

You may be wondering what role technology plays in a hydrographic survey.  I have already written about how modern survey operations rely on the use of multibeam sonar.  What I have not described, and am still coming to understand myself, is how complex the processing of sonar data is, involving different types of hardware and software.  

For example, when the sonar transducer sends out a pulse, most of the sound leaves and eventually comes back to the boat at an angle.  When sound or light waves move at an angle from one substance into another, or through a substance with varying density, they bend. You have probably observed this before and not realized it.  A plastic drinking straw in a glass of water will appear broken through the glass. That is because the light waves traveling from the straw to your eye bend as they travel.

Refraction in a glass of water
Refraction in a glass of water

The bending of a wave is called refraction. Sound waves refract, too, and this refraction can cause some issues with our survey data. Thanks to technology, there are ways to solve this problem. The sonar itself uses the sound velocity profile from our CTD casts in real time to adjust the data as we collect it. Later on during post processing, some of the data may need to be corrected again, using the CTD cast profiles most appropriate for that area at that general time. Corrections that would be difficult and time-consuming if done by hand are simplified with the use of technology.

Another interesting project in which I’ve been privileged to participate this week was setting up a base station at Shark Point in Ugak Bay.  You have most likely heard of the Global Positioning System, and you may know that GPS works by identifying your location on Earth’s surface relative to the known locations of satellites in orbit.  (For a great, kid-friendly explanation of GPS, I encourage students to check out this website.)  But what happens if the satellites aren’t quite where we think they are?  That’s where a base station, or ground station, becomes useful. Base stations, like the temporary one that we installed at Shark Point, are designed to improve the precision of positioning data, including the data used in the ship’s daily survey operations.

power source for the base station
Setting up the power source for the base station

Setting up the Base Station involved several steps.  First, a crew of six people were carried on RA-7, the ship’s small skiff, to the safest sandy area near Shark Point. It was a wet and windy trip over on the boat, but that was only the beginning! Then, we carried the gear we needed, including two tripods, two antennae (one FreeWave antenna to connect with the ship and a Trimble GPS antenna), a few flexible solar panels, two car batteries, a computer, and tools, through the brush and brambles and up as close to the benchmark as we could reasonably get.  A benchmark is a physical marker (in this case, a small bronze disk) installed in a location with a known elevation above mean sea level. For more information about the different kinds of survey markers, click here.

Base station installers
Base station installers: damp, but not discouraged

Next we laid out a tarp, set up the antennae on their tripods, and hooked them up to their temporary power source.  After ensuring that both antennae could communicate, one with the ship and the other with the satellites, we met back up with the boat to return to the ship.  The base station that we set up will be retrieved in about a week, once it has served its purpose.


Career Focus – Commanding Officer (CO), NOAA Corps

CO Ben Evans at dinner
CO Ben Evans enjoying dinner with the other NOAA Corps officers

Meet Ben Evans.  As the Commanding Officer of NOAA Ship Rainier, he is the leader, responsible for everything that takes place on board the ship as well as on the survey launches. Evans’ first responsibility is to the safety of the ship and its crew, ensuring that people are taking the appropriate steps to reduce the risks associated with working at sea.  He also spends a good deal of his time teaching younger members of the crew, strategizing with the other officers the technical details of the mission, and interpreting survey data for presentation to the regional office.

Evans grew up in upstate New York on Lake Ontario.  He knew that he wanted to work with water, but was unsure of what direction that might take him.  At Williams College he majored in Physics and then continued his education at Woods Hole Oceanographic Institution, completing their 3-year Engineering Degree Program.  While at WHOI, he learned about the NOAA Commissioned Officers Corps, and decided to apply.  After four months of training, he received his first assignment as a Junior Officer aboard NOAA Ship Rude surveying the waters of the Northeast and Mid-Atlantic.  Nearly two decades later, he is the Commanding Officer of his own ship in the fleet.

When asked what his favorite part of the job is, Evans smiled to himself and took a moment to reply.  He then described the fulfillment that comes with knowing that he is a small piece of an extensive, ongoing project–a hydrographic tradition that began back in 1807 with the United States Survey of the Coast.  He enjoys working with the young crew members of the ship, sharing in their successes and watching them grow so that together they may carry that tradition on into the future.

Danielle Koushel, NOAA Corps Junior Officer
Danielle Koushel, NOAA Corps Junior Officer, tracks our location on the chart


Personal Log

For my last post, I would like to talk about some of the amazing marine life that I have seen on this trip.  Seals, sea lions, and sea otters have shown themselves, sometimes in surprising places like the shipyard back in Seward.  Humpback whales escorted us almost daily on the way to and from our small boat survey near Ugak Bay. One day, bald eagles held a meeting on the beach of Ugak Island, four of them standing in a circle on the sand, as two others flew overhead, perhaps flying out for coffee.  Even the kelp, as dull as it might seem to some of my readers, undulated mysteriously at the surface of the water, reminding me of alien trees in a science fiction story.

Shark Point
Looking out over Shark Point from the base station

Stepping up onto dry land beneath Shark Point, we were dreading (yet also hoping for) an encounter with the great Kodiak brown bear. Instead of bears, we saw a surprising number of spring flowers, dotting the slopes in clumps of blue, purple, and pink. I am sensitive to the smells of a new place, and the heady aroma of green things mixed with the salty ocean spray made our cold, wet trek a pleasure for me.  


Word of the Day

Davit – a crane-like device used to move boats and other equipment on a ship


Speaking of Refraction…

Rainbow
Rainbows are caused by the refraction of light through the lower atmosphere

Thank you to NOAA Ship Rainier, the Teacher at Sea Program, and all of the other people who made this adventure possible.  This was an experience that I will never forget, and I cannot wait to share it with my students back in Georgia!

Jill Bartolotta: Sounds of the Deep, June 5, 2019

NOAA Teacher at Sea

Jill Bartolotta

Aboard NOAA Ship Okeanos Explorer

May 30 – June 14, 2019

Mission:  Mapping/Exploring the U.S. Southeastern Continental Margin and Blake Plateau

Geographic Area of Cruise: U.S. Southeastern Continental Margin, Blake Plateau

Date: June 5, 2019

Weather Data:

Latitude: 29°01.5’ N

Longitude: 079°16.0’ W

Wave Height: 2 feet

Wind Speed: 10 knots

Wind Direction: 128

Visibility: 10 nm

Air Temperature: 27.7°C

Barometric Pressure: 1021.3

Sky: few

Science and Technology Log

What is sonar?

Sonar is the use of sound to describe the marine environment. Sonar can be compared to satellites that use light to provide information about Earth, but instead of light, sound is used. It is used to develop nautical charts, detect hazards under the water, find shipwrecks, learn about characteristics of the water column such as biomass, and map the ocean floor. There are two types of sonar, active and passive. Active sonar is sonar that sends out its own sound wave. The sonar sends a sound wave (ping) out into the water and then waits for the sound to return. The return sound signal is called an echo. By assessing the time, angle, and strength of the return sound wave or echo one can learn many details about the marine environment. Passive sonar does not actively send out a sound ping, but rather listens for the sound from other objects or organisms in the water. These objects may be other vessels and these organisms may be whales or marine ecosystems such as coral reefs.

Sound waves move through the water at different speeds. These speeds are known as frequencies and the unit of measurement for sound is a hertz (Hz). Lower frequencies (example 18 kHz) are able to go farther down because they move slower and have more power behind them. It is like when a car goes down your street, pumping the bass (always seems to happen when I am trying to sleep) and you can hear it for a long time. That is because it is a low frequency and has longer wave lengths. Higher frequencies (example 200 kHz) move faster, but have less power. The sound waves should reach the bottom, an object, or biomass in the water column, but there may be no return or echo. High frequency sound waves are closer together. High frequencies give you a good image of what is happening near the surface of the water column and low frequencies give you a good idea of what is happening near, on, or under the ocean floor.

Type of Sonar on Okeanos Explorer

There are many types of sonar and other equipment aboard Okeanos Explorer for use during mapping operations. All have different capabilities and purposes. Together they provide a complete sound image of what is happening below us.

Kongsberg EM302 Multibeam Sonar

Multibeam sonar sends sound out into the water in a fan pattern below the hull (bottom) of the ship. It is able to map broad areas of the water column and seafloor from depths of 10 meters to 7,000 meters. Only the deepest trenches are out of its reach. It is the most appropriate sonar system to map seafloor features such as canyons and seamounts. The fan like beam it emits is 3-5.5x the water depth with a max swath range of 8 km. However, when you get to its depths below 5,000 meters the quality of the sound return is poor so scientists keep the swath range narrower to provide a higher quality of data return. The widest swath area scientists can use while maintaining quality is a depth of 3,300-5,000 meters. The user interface uses a color gradient to show you seafloor features (red=shallow and purple=deep).

Swath ranges for the multibeam sona
Swath ranges for the multibeam sonar at various depths. The y-axis shows the water depth in meters and the x-axis shows the swath width in meters. Photo credit: SST Charlie Wilkins, NOAA Ship Okeanos Explorer
Multibeam Sonar information
Some of the information that is collected using the multibeam sonar with labels describing their purpose. Photo Credit: NOAA OER

Backscatter

Backscatter uses the same pings from the multibeam. People use backscatter to model or predict physical or biological properties and composition of the sea floor. The coloring typically is in grayscale. A stronger echo looks brighter in the image. A weaker echo looks darker in the image. It gives you a birds-eye view of seafloor characteristics such as substrate density and seafloor features.

Backscatter and Bathymetry
Top image is backscatter showing you a birds-eye view of the ocean floor. The bottom image shows you what it looks like when backscatter is overlaid over the bathymetry layer. You are able to see intensity of the sound return, but floor features are more noticeable. Photo credit: NOAA OER

XBT

An Expendable Bathy-Thermograph (XBT) provides you with information on the temperature gradients within the water. When the temperature profile is applied to a salinity profile (taken from World Ocean Atlas) you are able to determine sound velocity or the rate at which the sound waves can travel through the water. When sound moves through water it does not move in a straight line. Its path is affected by density which is determined by water type (freshwater or saltwater) and temperature. Freshwater is less dense than saltwater and cold water is denser than warm water. The XBT information accounts for sound refraction (bending) through various water densities. When near shore XBTs are launched more frequently because the freshwater inputs from land alter density of the water and temperatures in the water column are more varied. XBTs are launched less frequently when farther from shore since freshwater inputs are reduced or nonexistent and the water column temperature is more stable. However, ocean currents such as the Gulf Stream (affecting us on this cruise) can affect density as well. The Gulf Stream brings warm water from the Gulf of Mexico around the tip of Florida and along the eastern coast of the United States. Therefore, one must also take into account which ocean currents are present in the region when determining the launch schedule of XBTs.

Loading the XBT Launcher
Senior Survey Technician Charlie Wilkins and Explorer in Training, Jahnelle Howe, loading the XBT launcher. XBTs are launched off the stern of the ship.
XBT Capture
Sound speed or velocity is determined by the density of the water, which is determined by temperature and salinity. Focus on the blue line in each graph. The first graph takes the information from the temperature and salinity graphs to determine sound speed. If we look at the first graph, we see that sound speed slows with depth. Sound speed slows because according to the second graph the temperature is colder making the water denser, thus affecting sound speed. Salinity does not vary much according to the third graph so its effect on density is most likely limited. Photo credit: NOAA OER

Simrad EK60 and EK80 Split-beam Sonar

Split-beam sonar sends out sound in single beam of sound (not a fan like the multibeam). Each transducer sends out its own frequency (example 18 kHz, 38 kHz, 70 KHz, 120 kHz, and 200 kHz). Some frequencies are run at the same time during mapping operations. Mapping operations typically do not use the 38 kHz frequency since it interferes with the multibeam sonar. Data collected with the use of the EK60 or EK80 provides information about the water column such as gaseous seeps, schools of fish, and other types of dense organism communities such as zooplankton. If you remember my “did you know” from the second blog, I discussed how sonar can be used to show the vertical diurnal migration of organisms. Well the EK60 or EK80 is the equipment that allows us to see these biological water column communities and their movements.

Water column information
Water column information collected with the EK60 or EK80 split beam sonar. If you look at the first row you can see, in the image to the left, the blue dots are at the top and in the second image the blue dots are moving back down into the water column as the sun rises. The process of organisms’ movement in the water column at night to feed is known as vertical diurnal migration. Photo Credit: NOAA OER

Knudsen 3260 Sub-bottom Profiler

The purpose of using a sub-bottom profiler is to learn more about the layers (up to 80 meters) below the ocean floor. It works in conjunction with the sonar mapping the ocean floor to provide more information about the bottom substrate, such as sediment type and topography features. Sub-bottom data is used by geologists to better understand the top layers of the ocean floor. A very low frequency is used (3.5 kHz) because it needs to penetrate the ocean sediment. It will give you a cross section of the sea floor so floor features can be detected.

Cross section of the ocean seafloor
Cross section of the ocean seafloor shows you substrate characteristics. Photo Credit: NOAA OER

Telepresence

Telepresence aboard the ship allows the science team to get mapping products and raw data to land on a daily basis. The science team can also live feed data collection to shore in real time. By allowing a land based shore team to see the data in real time you are adding another system of checks and balances. It is one more set of eyes to make sure the data being collected looks correct and there are no issues. It also allows a more collaborative approach to mapping, since you are able to involve a worldwide audience in the mission. Public viewers can tune in as well.  Support for the technology needed to allow telepresence capabilities comes in partnership with the Global Foundation of Ocean Exploration (GFOE). With GFOE’s help, the protocols, high-speed satellite networks, Internet services, web and social media interfaces, and many other tools are accessible when out to sea. The NOAA Office of Exploration and Research (OER) provides the experts needed to develop, maintain, and operate the telepresence systems while at sea, but also at shore through the Exploration Command Centers (ECCs) and the University of Rhode Island’s Inner Space Center.

Live interaction
Live interaction with Okeanos Explorer, Inner Space Center at URI/GSO, and a group of high school students. Photo credit: NOAA OER

All in all, the equipment aboard Okeanos Explorer is impressive in its abilities to provide the science team with a high quality and accurate depiction of the ocean floor and water column. The science team aboard is able to interpret the data, clean out unwanted data points, store massive data files on computers, and send it back to land daily, all while rocking away at sea. Very impressive and very cool!

Personal Log

I learned all about memes today. Apparently they are very popular on the ship. So popular, we are even in the middle of a meme contest. For those of you unfamiliar to memes like I was, a meme is a funny picture with a clever caption that makes you laugh or relates to something in your life. After my tutorial in meme making, we had a great time out on the bow of the ship playing corn hole and hanging out. The night was beautiful. The humidity subsided and there was a great breeze. After the sun set, I watched the stars come out and then went inside to learn more about the mapping process. I am starting to get a better understanding of what the science team is doing. You know the how and the why of it all. After I couldn’t keep my eyes open any longer, I made my nightly venture out onto the bow to look from some bioluminescence, the glittering of zooplankton in the night. A magical site. I will leave you wondering how the ocean glitters until one of my future blogs when I describe the process of bioluminescence.

Corn hole
General Vessel Assistant Sidney Dunn (left) and General Vessel Assistant Christian Lebron (right) playing corn hole on the bow at sunset.

Did You Know?

The SOFAR (Sound Fixing and Ranging) channel occurs in the world’s oceans between depths of 800 to 1000 meters in the water column. Because of the density and pressure around this channel, sound waves travel for an extended distance. It is thought that fin whales travel to this channel to communicate with other fin whales many kilometers away.

Jill Bartolotta: All Aboard, Shipping Out, May 30, 2019

NOAA Teacher at Sea

Jill Bartolotta

Aboard NOAA Ship Okeanos Explorer

May 30 – June 14, 2019

 

Mission:  Mapping/Exploring the U.S. Southeastern Continental Margin and Blake Plateau

Geographic Area of Cruise: U.S. Southeastern Continental Margin, Blake Plateau

Date: May 30, 2019

Weather Data:

Latitude: 24° 47.7 ‘N
Longitude: 080° 20.2’W
Wave Height: 2-3 feet
Wind Speed: 10 knots
Wind Direction: 114
Visibility: 10 nm
Air Temperature: 28.2°C
Barometric Pressure: 1013.5 mb
Sky: Few clouds

 

Science Log

Today we depart Key West. The days in port have been spent readying equipment, training mission crew, and exploring the beauty that is Key West. We say our final goodbyes to terra firma and head out to sea.

Ship sign board showing departure date
Departure time!
NOAA Ship Okeanos Explorer
Home for the next two weeks.

The ship we are aboard, NOAA Ship Okeanos Explorer, is managed by NOAA’s Office of Marine and Aviation Operations. The NOAA Commissioned Officer Corps commands and operates the ship in combination with wage mariners. Equipment on board is managed by NOAA’s Office of Exploration and Research (OER) in collaboration with the Global Foundation for Ocean Exploration.

If you visit OER’s website, you will see in their mission that they are the “only federal organization dedicated to ocean exploration. By using unique capabilities in terms of personnel, technology, infrastructure, and exploration missions, OER is reducing unknowns in deep-ocean areas and providing high-value environmental intelligence needed by NOAA and the nation to address both current and emerging science and management needs.” The purpose of OER is to explore the ocean, collect data, and make this data publicly available for research, education, ocean management, resource management, and decision-making purposes.

One of OER’s priorities is to map the US Exclusive Economic Zone (EEZ) at depths of 200 meters or greater. This is some deep stuff. The EEZ distance from shore is dependent on a variety of factors such as proximity to territorial waters of other countries and the continental shelf. If you want to learn more about how EEZs are established visit the United Nations Oceans and the Law of the Sea Website https://www.un.org/en/sections/issues-depth/oceans-and-law-sea/. Within the EEZ a country has exclusive rights to various activities such as fishing, drilling, ocean exploration, conservation, and resource management.

Map of U.S. Exclusive Economic Zone
Exclusive Economic Zone (EEZ) for the United States. We are mapping in the Southeast Region (lime green). Photo Credit: NOAA

We are currently en route to our mapping area so we can map previously unmapped areas. The mapping that will occur on this mission will be used to help inform dive locations for the ROV (Remotely Operated Vehicle) mission that will take place after our mission. Mapping allows us to understand sea floor characteristics and learn more about deep sea ecosystems that can be later explored with an ROV. An ecosystem of interest for this mapping mission is deep sea coral habitat. The area where we will be mapping is thought to be the largest deep sea coral habitat in US waters and it is largely unmapped. As data is collected, it is cleaned (more on this at a later time) of noise (unwanted data points). Products such as multi-beam geospatial layers are made available to end users on land roughly 24 hours after data is collected. End users could include other researchers, educators, ocean policy and management decision-makers, and more specifically those who will be joining the ROV mission happening in two weeks.

If you want to follow Okeanos Explorer and her crew on our mission, see the live feed available through this link https://oceanexplorer.noaa.gov/livestreams/welcome.html.

Personal Log

We have just left port. The dolphins are jumping, the sea is the most perfect turquoise blue, and the wind blows on our sun-kissed faces. I have left port many times on my various trips, but today was magical. I think what makes this departure from port so magical is the journey that lies ahead. I am nervous and excited all at the same time. It is slowly settling in that I am able to participate in this once in a lifetime experience. Never in my wildest dreams did I think I would be aboard an ocean exploration vessel. Wow! Just Wow!

View of Key West from shore
Fondest farewell Key West.

So far everything is good. Dabbled pretty hard in the seasickness world today. I tried to get on my computer too early and it went down swell from there. However, some wind on my face, ginger soup, and bubbly water made everything better. Many people have told me it is important to embark on a task to get my mind off feeling unwell. I have taken this to heart and have been meeting all the wonderful people on the ship, learning more about them and their role on the ship. In the coming two weeks, I plan on learning about every facet that it takes to operate an exploration mission. From what makes the ship move forward to the detailed intricacies of mapping the sea floor to those who make it all possible.

I hope I will be able to share my experience with you so it feels like you are with me on the ship. Using words and pictures I will try to make you feel as if you are aboard with all of us. I will do my best to show you the blue hues we encountered today and explain what it is like to be out to sea with land many miles away. But I still encourage you all to try it for yourself. Words and images will only give you half the story. You need to feel the rest firsthand.

Blue water out of Key West
Bluest of blues. Words and images fail me here. The blue hues we saw today are the most spectacular colors I have ever seen.

Sunset is upon the horizon so I leave you for now. Stay tuned for more about our grand adventure.

Sun sets over the ocean
First sunset at sea

Did You Know?

You can use sonar to learn more about the organisms living in the water column. For example, sonar has the ability to show you the migration of zooplankton and their predators to the surface at night and back down when the sun rises. This phenomenon is called vertical diurnal migration.

Ship Words

Different terms are used to describe items, locations, or parts of the ship. As I learn new words I would like to share my new vocabulary with all of you. If there is a ship term you want to know more about let me know and I will find out!

Port: Left side of ship

Starboard: Right side of ship

Bow: Front of ship

Stern: Back of ship

Mess Deck: Where we eat

Head: Restroom

Scuttlebutt: Water fountain (and gossip)

Bulkhead: Walls

Overhead: Ceilings

Deck: Floor

Rack: Bed

Aft: Towards the back of the ship

Forward: Towards the front of the ship

Animals Seen Today

One dolphin

Hundreds of flying fish

Dozens of various seabirds

David Tourtellot: A Musical Perspective of Sonar, July 24, 2018

NOAA Teacher at Sea

David Tourtellot

Aboard NOAA Ship Thomas Jefferson

July 9-26, 2018

Mission:  Hydrographic Survey – Approaches to Houston

Geographic Area of Cruise: Gulf of Mexico

Date: July 24th, 2018

Weather Data from the Bridge

Latitude: 29°09.1270’N

Longitude: 093°46.5544’W

Visibility: 5 Nautical Miles

Sky Condition: 8/8

Wind: Direction: 70.1°, Speed: 13.3 knots

Temperature:

Seawater: 29.24°C

Air: Dry bulb:26.9°C          Wet bulb: 24.7°C

 

Science and Technology Log

Coming to NOAA Ship Thomas Jefferson, I was eager to learn all I could about sonar. I am amazed that we have the ability to explore the ocean floor using sound.

uncharted wreck

An uncharted wreck discovered by NOAA Ship Thomas Jefferson

Over the course of my previous blog entries, I have described the tools and processes used to survey using sonar. This time, I am going to try to frame the sounds that the sonars are using in a musical context, in the hope that doing so will help students (and myself) better understand the underlying concepts.

Note – many aspects of music are not standardized. For the purpose of this blog post, all musical tuning will be in equal temperament, at A=440. When I reference the range of a piano, I will be referencing a standard 88-key instrument. Many of the sonar frequencies do not correspond exactly to an in-tune pitch, so they have been written to the nearest pitch, with a comment regarding if the true frequency is higher or lower than the one written.

In sonar and in music, when considering soundwaves it is important to know their frequency, a measure of how many waves occur over the course of a set period of time. Frequency is measured in a unit called Hertz (abbreviated as Hz), which measures how many soundwaves occur in one second. One Hertz is equal to one soundwave per second. For example, if you heard a sound with a frequency of 100Hz, your ears would be detecting 100 soundwaves every second. Musicians also are concerned with frequency, but will use another name for it: pitch. These words are synonymous – sounds that are higher in pitch are higher in frequency, and sounds that are lower in pitch are lower in frequency.

Below are the eight octaves of the note A that are found on a piano, each labeled with their frequency. The notes’ frequencies have an exponential relationship – as you move from low to high by octave, each note has a frequency that is double that of its predecessor.

Piano As with frequencies

The frequency of each A on a piano

The highest note on a piano, C, has a frequency of 4186.01Hz

Highest Note on a piano

The frequency of the highest note on a piano

Average, healthy young humans hear sounds ranging from 20Hz to 20,000Hz. All sounds outside of that range are inaudible to people, but otherwise no different from sounds that fall within the human range of hearing. The highest note we would be able to hear would be an E♭, at a frequency of 19,912.16Hz (a frequency of exactly 20,000Hz would fall in between E♭ and E♮, though would be closer to E♭). If put on a musical staff, it would look like this:

High Eb 19kHz

The frequency of the highest note in the human range of hearing

The hull of NOAA Ship Thomas Jefferson is equipped with several sonar transmitters and receivers, which can operate at a wide variety of frequencies.

TJ Sonar

The hull of NOAA Ship Thomas Jefferson, with several sonars. Note that the projectors that transmit lower frequencies are larger than the ones that transmit higher frequencies. This is similar to musical instruments – instruments that make lower sounds, like the tuba or the double bass, are larger than instruments that make higher sounds, like the trumpet or the violin

Higher frequencies provide higher resolution returns for the sonar, but they dissipate more quickly as they travel through water than lower frequencies do. Surveyors assess the depth of the water they are surveying, and choose the frequency that will give them the best return based on their conditions. Most of the sonar frequencies are too high for humans to hear. The ship’s multi-beam echo sounder has a variable frequency range of 200,000Hz-400,000Hz, though as I’ve been on board they’ve been scanning with it at 300,000Hz. Likewise, the multi-beam sonars on the launches have also been running at 300,000Hz. The ship has a sub-bottom profiler, which is a sonar used for surveying beneath the seafloor. It operates at a frequency of 12,000Hz, and has the distinction of being the only sonar on the ship that is audible to humans, however, we have not had a need to use it during my time aboard the Thomas Jefferson.

The ship’s side scan towfish (which I described in my previous blog entry) operates at 455,000Hz.

Here, we can see what those frequencies would look like if they were to be put on a musical staff.

Assorted Sonars and reference pitches

The frequencies of sonar, with reference pitches

Altering the frequency isn’t the only way to affect the quality of the reading which the sonar is getting. Surveyors can also change the pulse of the sonar. The pulse is the duration of the ping. To think about it in musical terms, changing the pulse would be akin to switching from playing quarter notes to playing half notes, while keeping the tempo and pitch the same. Different sonar pulses yield different readings. Shorter pulses provide higher resolution, but like higher frequency pings, dissipate faster in water, whereas longer pulses provide lower resolution, but can reach greater depths.

Personal Log

Mariners have a reputation for being a rather superstitious bunch, so I decided to ask around to see if that held true for the crew of the Thomas Jefferson. Overall, I found that most didn’t strictly adhere to any, but they were happy to share some of their favorites.

Everyone I spoke to told me that it is considered bad luck to leave port on a Friday, though the Commanding Officer, CDR Chris van Westendorp, assured me that you could counteract that bad luck by making three 360° turns to the left as soon as the ship is able. Many on the crew are also avid fishermen, and told me that bringing bananas aboard would lead to a bad catch, and one went so far as to be mistrustful of yellow lighters as well.

Certain tattoos are said to bring good luck – I was told that sailors often have a chicken and a pig tattooed on their feet. According to custom, those animals were often stored in wooden crates that would float if a ship went down, and having them tattooed onto you would afford you the same benefit. When asked if he was superstitious one of our helmsmen Jim proudly showed me a tattoo he has of a dolphin. He explained that having a sea creature tattooed on your body would prevent drowning. “It works!” he said with a grin, “I’ve never drowned!”

Several maritime superstitions deal with foul weather. Umbrellas are said to cause bad weather, as is split pea soup. Whistling while on the bridge is said to “whistle in the winds.” While not a superstition per se, many crew members told me variations of the same meteorological mantra: Red sky at night, sailor’s delight. Red sky in the morning, sailors take warning.

One of the NOAA Corps Officers aboard, ENS Garrison Grant, knew several old superstitions related to shipbuilding. When laying the keel (the first piece of the ship to be put into place), shipbuilders would scatter evergreen boughs and tie red ribbons around it to ward off witches. Historically, having women aboard was considered bad luck, though, conversely it was said that if they showed their bare breasts to a storm, it would subside. This is why several ancient ships had topless women carved into the masthead. Legend has it that in order to assure that a ship would float, when it was ready to be launched for the first time, virgins would be tied to the rails that guided the ship from the ship yard into the water. The weight of the ship would crush them, and their blood would act as a lubricant, allowing the ship to slide into the water for the first time. Yikes! Thankfully, as society became more civilized, this practice evolved into the custom of breaking a bottle of champagne against a ship’s bow!

Did you know? Musical instruments play an important role in ship safety! In accordance with maritime law, ships will use auditory cues to make other vessels aware of their presence in heavy fog. For large ships, this includes the ringing of a gong at regular intervals.

Latest Highlight: During this week’s fire drill, I got to try the fire hose. It was very powerful and a lot of fun!

David Tourtellot during a fire drill

David Tourtellot during a fire drill

David Tourtellot: The Speed of Sound, July 15, 2018

NOAA Teacher at Sea

David Tourtellot

Aboard NOAA Ship Thomas Jefferson

July 9-26, 2018

Mission:  Hydrographic Survey – Approaches to Houston

Geographic Area of Cruise: Gulf of Mexico

Date: July 15th, 2018

Weather Data from the Bridge

Latitude: 28° 49.4115’N

Longitude: 93° 37.4893’W

Visibility: 10+ Nautical Miles

Sky Condition: 4/8

Wind: Direction: 240°, Speed: 7 knots

Temperature:

Seawater: 31.7°C

Air: Dry bulb:31.5°C          Wet bulb: 27.5°C

 

Science and Technology Log

 

NOAA Ship Thomas Jefferson is well underway in its mission of surveying the seafloor. The primary tool that the ship (as well as its 2 Hydrographic Survey Launches) is using to accomplish this task is sonar. Sonar was originally an acronym for SOund Navigation And Ranging. If you are familiar with echolocation – the system that some animals (such as bats and dolphins) use to navigate their surroundings – then you already have a basic understanding of how sonar works. The sonar transmits a short sound (called a ping) that will travel down, away from the ship, until it hits the seafloor. At this point, it will reflect off of the sea floor, and echo back up to the ship, where it is detected by the sonar’s receiver. The crew aboard are then able to calculate the depth of the water.

To make the necessary calculations, there are 3 variables at play: the time that it takes for the ping to travel; the distance that the ping travels; and the velocity, or the speed, at which the ping moves through the water. If we know two of those variables, it is easy to calculate the third.

When using sonar to determine the depth of the water, distance is the unknown variable – that’s what we’re ultimately trying to figure out. To do so, we need to know the other two variables. Time is an easy variable for the sonar to measure. The sonar has a transmitter, which generates the ping, and a receiver, which hears it. These two components communicate with one another to give us an accurate measure of time. The third variable, velocity, is a bit trickier.

In saltwater, sound travels approximately 1500 meters per second. However, that rate can vary slightly based on water conditions such as temperature and salinity (how salty the water is). In order for sonar to get as accurate a reading as possible, it needs to calculate the precise speed of sound for the particular water it is in at the moment. The sonar is able to do that by using a component called a sound velocity sensor, known colloquially as a singaround.

Sonar 1 Singaround

The sonar on the hull of one of the Hydrographic Survey Launches. The orange rectangles are the projector (or, the transmitter) and the receiver, and the component in the green circle is the singaround

A singaround looks like a bar with a nub on each end. One nub is a projector, and the other is a reflector. The projector broadcasts a ping that travels parallel to the hull of the ship, bounces off of the reflector, and returns to the projector. We use that information to calculate velocity. The calculation uses the same 3 variables as above (time, distance, and velocity), but this time, distance isn’t the unknown variable anymore – we know exactly how far the ping has traveled, because we know how far the projector and reflector are from one another. The singaround electronically measures how long it takes for the ping to travel, and since we now know two of the variables (distance and time) we can calculate the third (velocity) for our particular water conditions at the face of the sonar.

Sound travels roughly 4 times faster in water than it does in air (this is because water is denser than air). To ensure that the sonar gets an accurate reading, it is important that air bubbles don’t get in the way. The boat’s hull (bottom) has a triangular metal plate directly in front of the sonar, which routes air bubbles around to the side of the sonar.

Sonar 2

The hull of one of the Hydrographic Survey Launches.

 

Personal Log

Each day, the ship’s CO (Commanding Officer) publishes a POD, or Plan Of the Day. This is full of important information – it tells us what the ship will be doing; if/when we will deploy the launch boats, and who will be on them; what time meals will be; and the expected weather conditions. Below is an example from Friday, July 13th.

Plan of the Day

NOAA Ship Thomas Jefferson Plan of the Day for Friday, July 13, 2018

On Friday, I had the opportunity to go out on one of the Hydrographic Survey Launches. Because of their smaller size, the launch boats are great for surveying difficult to maneuver areas. For instance, we spent most of the day surveying an area near an oil rig, and were able to get much closer than the Thomas Jefferson could.

Mike Below Deck

Survey Tech Mike Hewlett collecting and analyzing survey data aboard a launch boat

Oil Rig and Boat

An oil rig and a supply vessel

I’ve been very impressed by how multi-talented everyone on the ship seems to be. In addition to analyzing data, the ship’s survey techs can also be found handling lines as the survey boats are launched and recovered, and do a lot of troubleshooting of the hardware and software they’re using. The coxswains (people who drive small boats) double as engineers, fixing issues on the launch vessels when away from the ship. I’m surrounded by some very gifted people!

Fixing the AC

Coxswain Francine Grains and Survey Tech Brennan Walters fixing the air conditioner on one of the launch boats that had stopped working unexpectedly. They had it up and running in no time

Did you know?: As president, Thomas Jefferson ordered the first survey of the coastline of the United States. Because of this, NOAA Ship Thomas Jefferson is named for him. 

Latest Highlight: While surveying, we spotted a water spout in the distance. A water spout is a tornado that forms over water. Luckily, we were a safe distance away. It was an amazing sight to see!

 

Brandy Hill: What Lies Beneath the Surface, July 1, 2018

NOAA Teacher at Sea

Brandy Hill

Aboard NOAA ship Thomas Jefferson

June 25, 2018 –  July 6, 2018

 

Mission: Hydrographic Survey- Approaches to Houston

Geographic Area of Cruise: Gulf of Mexico

Date: July 1, 2018

 

Weather Data from the Bridge

Latitude: 29° 10.1’ N

Longitude: 093° 54.5’ W

Visibility: 10+ NM

Sky Condition: 3/8

Wind: 16 kts

Temperature:

Sea Water: 29.4° C

Air: 27° C

 

Science and Technology Log

At this point I have been able to understand more of the sonar technology taking place during the survey aboard the Thomas Jefferson. The ship uses two types of sonar: multibeam and side scan. Both work together transmitting and receiving sound pulses to and from the ocean floor. This provides a multispectral analysis.

Julia Wallace, a physical scientist, works at the sonar acquisition station. This requires a large amount of multitasking as she communicates with the bridge (ship steering deck), watches the safety cameras, and makes sure both sonar devices are working correctly.

Julia Wallace, a physical scientist, works at the sonar acquisition station. This requires a large amount of multitasking as she communicates with the bridge (ship steering deck), watches the safety cameras, and makes sure both sonar devices are working correctly.

Multibeam sonar is located underneath the hull of the ship. Multibeam is used to detect bathymetry (the depth of the ocean floor). Multibeam backscatter (reflected wave energy) gives a reading of the surface intensity. For example, a strong signal would mean a harder surface like rock or pipeline. With multibeam sonar, you can also adjust the sound wave frequency. For example, high frequency (primarily used during this survey in the Gulf of Mexico) is used for shallower waters allowing for higher resolution images. Images from multibeam have a color gradient to allow for clear vision of contours and depth differences. One way surveyors aboard the TJ may use backscatter images is to determine areas where bottom sampling might be applicable.

A NOAA ship using mulitbeam sonar. (Courtesy of NOAA)

A NOAA ship using mulitbeam sonar. (Courtesy of NOAA)

Bathymetry acquired using multibeam echosounder layered over a nautical chart.  Blue and green wave lengths penetrate further in water, so the coloring corresponds to this observation. This poster is from a previous Thomas Jefferson hydrographic survey near Savannah, Georgia. (Prepared by CHST Allison Stone)

Bathymetry acquired using multibeam echosounder layered over a nautical chart.  Blue and green wave lengths penetrate further in water, so the coloring corresponds to this observation. This poster is from a previous Thomas Jefferson hydrographic survey near Savannah, Georgia. (Prepared by CHST Allison Stone)

3D bathymetry imagery from the Okeanos Explorer. (NOAA)

3D bathymetry imagery from the Okeanos Explorer. (NOAA)

A close-up view of multibeam data. The third window down shows multibeam backscatter.

A close-up view of multibeam data. The third window down shows multibeam backscatter.

The side scan sonar is used alongside multibeam to provide black and white scans of images. Like multibeam backscatter, side scan measures the intensity of the sound returning from the sea floor. For example, a side scan return with high intensity could indicate a difference in material like pipeline or a wreck. A low intensity value could mean that the side scan sonar waves have reached a muddy substrate. Julia used the analogy of a tennis ball being bounced against a wall of different materials. For example, the tennis ball hitting a concrete wall would bounce back with higher intensity than one being bounced against a soft wall. Side scan sonar is very effective at detecting features that protrude off the sea floor, and for shallow water surveys, typically can see farther and cover a greater area the sea floor than multibeam echosounders alone.

The side scan sonar sensor is located on a torpedo-shaped “towfish” and pulled behind the boat. When viewing side scan images, surveyors typically look for the acoustic shadow cast by a feature protruding off the sea floor. By measuring the length of the acoustic shadow, hydrographers can determine whether the feature requires additional investigation. For example, the outline of a shipwreck, bicycle, or pipeline. However, it can also detect mammals like dolphins or schools of fish.

Diagram of side scan sonar. (Courtesy of thunder bay 2001, Institute for Exploration, NOAA-OER)

Diagram of side scan sonar. (Courtesy of thunder bay 2001, Institute for Exploration, NOAA-OER)

The Thomas Jefferson sidescan sonar on deck.

The Thomas Jefferson sidescan sonar on deck.

In the early morning, the sidescan sonar picked up the image of an incorrectly charted shipwreck. Height is estimated using the "shadow" of the wreck.

In the early morning, the sidescan sonar picked up the image of an incorrectly charted shipwreck. Height is estimated using the “shadow” of the wreck.

Sidescan sonar imagery layered on a nautical chart. It is important to remember that sidescan data does not account for depth, it is a measure of differences in sea floor substrate.

Sidescan sonar imagery layered on a nautical chart. It is important to remember that sidescan data does not account for depth, it is a measure of differences in sea floor substrate.

Look closely and you can see arc lines in the sidescan imagery. Lt. Anthony Klemm explains that these arcs are from ships dragging anchor and stirring up the sea floor.

Look closely and you can see arc lines in the sidescan imagery. Lt. Anthony Klemm explains that these arcs are from ships dragging anchor and stirring up the sea floor.

While this is happening, surveyors are also towing a MVP or Moving Vessel Profiler to capture information about the water column. This is important because multiple factors in the water column need to be corrected in order for accurate sonar calculations. For example, the speed of sound in salt water is roughly 1500 m/s but may change while the ship is traveling over different parts of the sea floor or passing through a thermocline (steep temperature gradient) or halocline (steep salinity gradient). The MVP is similar to the CTD used on the launch boat (see previous post), but the MVP allows the ship to continue moving at about 10 knots (average survey speed), while the CTD must be cast when the ship is stationary.

Information from the Moving Vessel Profiler. From left to right, the MVP tracks sound speed, temperature, and salinity in relation to depth.

Information from the Moving Vessel Profiler. From left to right, the MVP tracks sound speed, temperature, and salinity in relation to depth.

For more information on multispectral analysis and sonar, see these resources:

https://oceanexplorer.noaa.gov/explorations/09bermuda/background/multibeam/multibeam.html

https://oceanservice.noaa.gov/education/seafloor-mapping/how_sidescansonar.html

Personal Log

One of my goals in the classroom is to teach students to be comfortable making and learning from mistakes. Making mistakes in math and science is common and welcome because they lead to great discussion and future change. Often, my sixth graders get discouraged or so caught up in failure that they become paralyzed in making further attempts. While aboard the Thomas Jefferson, I have witnessed several aspects not go according to plan. I think these experiences are important to share because they provide real-life examples of professionals coming together, learning from mistakes, and moving forward.

Around 4:00 am, the towfish side scan sonar became entangled with the MVP. This was a horrendous disaster. The crew spent about 16 hours contemplating the issue and collecting data using the multibeam only, which is less than ideal.  One of XO LCDR McGovern’s many roles aboard the ship is to serve as the investigator. She reviewed tapes of the early morning, talked with the crew, and later held a debrief with all involved. When something like this happens, the ship must write a clear incident report to send to shore. There were many questions about why and how this happened as well how to best proceed. In the end, the towfish and MVP were untangled with no damage present to the sensor. Within the same day, both were cast out and back in use.

I find this to be an astounding example of perseverance and teamwork. Despite being disappointed and upset that a critical tool for collecting accurate data was in dire shape, the crew came up with a plan of action and executed. Part of the engineering and scientific processes include evaluation and redesign. Elements of the sea and a center drift of the side scan lead to a documented new plan and refiguring the process so that this is unlikely to happen again.

Lt. Charles Wisotzsky's sketch of the complications with launching both the sidescan sonar (which tends to centerline) and MVP towfish with a current coming from port side.

Lt. Charles Wisotzsky’s sketch of the complications with launching both the sidescan sonar (which tends to centerline) and MVP towfish with a current coming from port side.

This camera image captures the entanglement of the sidescan sonar and MVP.

This camera image captures the entanglement of the sidescan sonar and MVP.

Peaks

+Saw a tuna eat a flying fish

Flying Fish. (www.ocean.si.edu)

Flying Fish. (www.ocean.si.edu)

+There is a large sense of purpose on the ship. Despite complex sleep schedules to enable 24 hour operations with a smaller crew, people are generally happy and working hard.

+ There seems to be an unlimited supply of ice cream in the ice cream freezer. Junior Officer, ENS Garrison Grant introduced me to a new desert- vanilla ice cream, a scoop of crunchy peanut butter, and chocolate syrup. I also found the rainbow sprinkles.

David Amidon: Science @ Sea, June 8, 2017

NOAA Teacher at Sea

David Amidon

Aboard NOAA Ship Reuben Lasker

June 2 – 13, 2017

Mission: Pelagic Juvenile Rockfish Recruitment and Ecosystem Assessment Survey

Geographic Area of Cruise: Pacific Ocean off the California Coast

Date: June 8, 2017

 

 

 

Science and Technology Log

The main scientific research being completed on the Reuben Lasker during this voyage is the Pelagic Juvenile Rockfish Recruitment and Ecosystem Assessment Survey and it drives the overall research on the ship during this voyage. Rockfish are an important commercial fishery for the West Coast. Maintaining healthy populations are critical to maintaining the fish as a sustainable resource. The samples harvested by the crew play an important role in establishing fishery regulations. However, there is more happening than simply counting rockfish here on the ship.

How does it work? Let me try to explain it a bit.

 

First, the ship will transfer to a specific location at sea they call a “Station.”

IMG_1590

Collection stations off the California Coast that the Reuben Lasker trawls annually.

For a half hour prior to arrival, a science crew member will have been observing for Marine Mammals from the bridge area. When the station is reached, a new observer from the science crew will take over the watch outside on the deck. The fishermen on the boat crew will then unwind the net and launch it behind the boat. It must be monitored from the deck in order to ensure it is located 30 m below the surface. Once everything is set, then the ship trawls with the net at approximately 2 knots. Everything must be consistent from station to station, year to year in order to follow the standardized methods and allow the data recorded to be comparable. After the 15 minutes, then the crew pulls the net in and collects the sample from the net. This process is potentially dangerous, so safety is a priority. Science crew members can not go on the deck as they have not received the proper training.

 

 

Timelapse video of the fishermen bringing in a catch. 6/7/17 (No sound)

 

Once the sample is hauled in, the science personnel decide which method will be used to establish a representative sample. They pull out a sample that would most likely represent the whole catch in a smaller volume. Then we sort the catch by species. After completing the representative samples, they will eventually stop taking counts of the more abundant organisms, like krill. They will measure the volume of those creatures collected and extrapolate the total population collected by counting a smaller representative sample. Finally, we counted out all of the less abundant organisms, such as squid, lanternfish and, of course, rockfish. After the sample is collected and separated, Chief Scientist Sakuma collects all of the rockfish and prepares them for future investigations on shore.  

 

 

A selection of species caught off the coast of San Clemente. These include Market Squid, Anchovies, Red Crab, King-of-Salmon (the long ribbonfish), and Butterfish, among others.

NOAA has used this platform as an opportunity. Having a ship like the Reuben Lasker, and the David Starr Jordan before that, collecting the samples as it does, creates a resource for furtAher investigations. During the trawls we have catalogued many other species. Some of the species we analyzed include Sanddab, Salp, Pyrosoma, Market Squid, Pacific Hake, Octopus, Blue Lanternfish, California Headlightfish and Blacktip Squid, among others. By plotting the biodiversity and comparing the levels we recorded with the historic values from the stations, we gain information about the overall health of the ecosystem.

What happens to the organisms we collect? Not all of the catch is dumped overboard. Often, we are placing select organisms in bags as specimens that will be delivered to various labs up and down the coast.

IMG_1519

Collecting subsets for classification

This is a tremendous resource for researchers, as there is really no way for many of these groups to retrieve samples on their own. Rachel Zuercher joined the crew during this survey in part to collect samples to aid in her research for her PhD.

Along with the general species analysis, the team specifically analyzes the abundance of specific krill species. Krill forms the base of the marine ecosystems in the pelagic zone. They are a major food source for many species, from fish to whales. However, different krill species are favored by different consumers. Therefore, an extension of the Ecosystem Assessment involves determining the abundance of specific krill species. Thomas Adams has been responsible for further analyzing the krill collected. He counts out the representative sample and use microscopes to identify the species collected based on their physical characteristics.  

Additionally, at most stations a Conductivity, Temperature and Depth cast (CTD) is conducted. Basically, bottles are sent overboard and are opened at a specified depth.

IMG_1589

The apparatus for collecting water during CTD casts

Then they are collected and the contents are analyzed. Often these happen during the day prior to the Night Shift taking over, with final analysis taking place after the cruise is complete. This data is then connected with the catch numbers to further the analysis. Ken Baltz, an oceanographer on the ship, uses this information to determine the production of the phytoplankton based on the amounts of chlorophyll detected at depth. This is an important part of the food web and by adding in this component, it makes the picture below the surface clearer.

 

 

img_1488.jpg

NOAA Corps’ Ryan Belcher completing the CTD collection for a station.

Finally, there are two more scientific investigations running as we cruise the open seas during the daylight hours. Michael Pierce is a birdwatcher from the Farallon Institute for Advanced Ecosystem Research who is conducting a transect survey of Seabirds and Marine Mammals. He is based on the Flying Bridge and catalogs any birds or marine mammals that pass within 300 meters of the ship’s bow. Although difficult, this study attempts to create a standardized method for data collection of this nature. As he explained, birds are more perceptive than we are – what looks like open ocean really varies in terms of temperature, salinity and diversity below the surface. Therefore, birds tend to favor certain areas over others. These are also important components of the food web as they represent upper level predators that are not collected in the trawl net. Also, on the bottom of the ship transducers are installed that are able to gather information through the EK60 Echosounder. This sonar can accurately identify krill populations and schools of fish underwater. Again, adding the data collected from these surveys help create a much more complete understanding of the food web we are analyzing out on the open sea.

 

IMG_1591

Sonar data from the EK60

Personal Log

 

Sunday, June 4

The waves were very active all day. Boy am I glad I’m wearing the patch. There was so much wind and the waves were so high, there was a question if we were even going to send the net out. High wind and waves obviously add an element of concern, especially for the safety of the boat crew working the net.

I spent some of the day up on the Bridge- the section of the boat with all of the navigation equipment. The Executive Officer (XO) gave me an impromptu lesson about using the map for navigation. They have state-of-the-art navigation equipment, but they also run a backup completed by hand and using a compass and straightedge just like you would in math class. Of note – the Dungeness Crab season is wrapping up and many fishermen leave traps in the water to catch them. When the boat is passing through one of these areas, someone will act like a spotter so the boat can avoid getting tangled up. When I was looking with him, we saw some whale plumes in the distance.

We did launch the net twice Sunday night, collecting a TON of krill each time. In the first batch, we also caught some squid and other small prey species. The second trawl was very surprising. Despite cutting it down to a 5 minute trawl, we caught about the same amount of krill. We also caught more squid and a lot of young salmon who were probably feeding on the krill.  

IMG_1493

That is a ton of krill!

 

Monday, June 5

I am getting used to the hours now – and do not feel as guilty sleeping past 2PM considering we are up past 6 in the morning. It will make for a tricky transition back to “the real world” when I go home to NY!

During the day, spent some time just talking with the science folks and learning about the various tasks being completed. I also spent some time up on the Flying Bridge as they said they had seen some Mola, or Giant Ocean Sunfish (although I did not see them). I did have a chance to make a few videos to send to my son Aiden’s 3rd grade teacher back in NY. It did not work out as well as I had hoped, but considering we are out in the middle of the ocean, I really can’t complain about spotty wi-fi.

Once we started the night shift, we really had a good night. We completed work at 5 stations – which takes a lot of time. We saw a LOT of biodiversity last night – easily doubling if not tripling  our juvenile rockfish count. We also saw a huge variety of other juvenile fish and invertebrates over the course of the night. We finally wrapped up at 6:30 AM, what a night!

Tuesday, June 6th

We found out today that we will need to dock the ship prematurely. There is a mechanical issue that needs attention. We are en route straight through to San Diego, so no fishing tonight. However, our timing will not allow us to reach port during the day, so we will get a chance to sample the southernmost stations Wednesday night. Thus is life at sea. The science crew is staying on schedule as we, hopefully, will be back on the water this weekend.

Wednesday, June 7th

After a day travelling to San Diego, we stopped at the stations near San Clemente to collect samples. Being much farther south than before, we saw some new species – red crabs, sardines and A LOT of anchovies. Closer to shore, these counts dropped significantly and krill showed up in numbers not seen in the deeper trawl. Again, I am amazed by the differences we see in only a short distance.

 

More from our anchovy haul- the bucket contains the entire catch from our second trawl, the tray shows how we analyzed a subset. Also on the tray you find Red Crab, Salps, Mexican Lanternfish and Krill.