Mission: Hydrographic Survey of the Pribilof Islands
Geographic Area of Cruise: Pribilof Islands, Alaska
Date: July 16, 2023
Weather Data
Location: 55’21.02° N, 161’02.02° W
Outside temperature: 11°C
Water temperature: 10°C
True Winds: 337°, 6.5 kts
Skies: Overcast and Cloudy
Science and Technology Log
What is Surveying?
I was in port with the NOAA Ship Fairweather for a little under a week but right now we are en route to the Pribilof Islands. During the time at port, the survey team surveyed surrounding areas, calibrated equipment and practiced troubleshooting survey systems. The goal of surveying is to gather the bathymetry data of the seafloor, or the depths and shape of the seafloor.
Surveying equipment is located on NOAA Ship Fairweather as well as four smaller boats called survey launches, which each get deployed from the ship. Depending on the mission, sea conditions and the project plan, the ship or launches may both be used, or a combination of both.
Global Positioning System (GPS) records position. The Inertial Measurement Units (IMU) measures the motion of the ship. Multibeam Echosounder (MBES) is when sound is pinged from a vessel to the seafloor and the time lapse is used to determine the depth of the seafloor. MBES is a type of sonar that uses multiple beams to get a more complete picture of the seafloor with depths and characteristics. After the data is pinpointed to a specific location, variability associated with tides is also taken into account by transforming the data vertically to the mean lowest low tide. Bathymetry data taken on NOAA Ship Fairweather as well as its four survey launches appears as strips on a map, as the ship or boat moves.
Data is measured to the mean lowest low tide because that level of water is on average the lowest of any tide for a given area. Using the lowest depth in navigation is conservative, thus allowing vessels to navigate safely through mapped waters.
Survey Data shown as green strips.
Survey launches being stored on NOAA Ship Fairweather as well as one deployed in the harbor
TAS Elli Simonen aboard one of the survey launches.
Calibrating the Data
During our time in port we took out some of the survey launches to perform a patch test; that is, calibration procedures to ensure the data we collect is as accurate as possible. A correctly calibrated system will show the same mapping of the seafloor in repeated tests, without the influence of confounding variables – speed, direction and ship motion. In a patch test, time delay, pitch, roll and heading are calculated multiple times over different depths, obstructions and slopes on the seafloor and compared to known data. The obstruction we surveyed was a shipwreck.
Planning the Patch Test
Map of the planned surveys for the Patch Test.
Survey Data showing the Wreck
To correct for how the speed of sound changes in ocean water, during surveying every four hours Conductivity, Temperature and Depth (CTD) is measured. The CTD measures Salinity and Pressure of the Water Column, aspects that can change the speed of sound. The CTD is used to further calibrate data because different depths have different levels of salinity and temperature, and therefore distort how fast the sound travels. CTD data is used in post-processing to correct for any distortions.
CTD on the survey launches.
Moving Vessel Profiler (MVP), a type of CTD that can be used while the ship is in motion, being deployed on NOAA Ship Fairweather by members of the surveying team.
Where does the data go?
Once the survey technicians gather bathymetry data, they still need to edit it before passing it along to National Centers for Environmental Information (NCEI), who package it for public view and is the data repository for environmental data in the U.S. and the U.S. Office of Coast Survey who create navigational charts. Editing the data involves rejecting spurious noise that MBES picked up that is out of range or incorrect. This data then is transformed into charts and more standardized bathymetry data.
Survey Technician showing TAS Elli Simonen the process of cleaning survey data
Personal Log
Members of the survey team are all smart, respectful and patient and take the time to explain to me the science at play no matter how many questions I have. I spend the majority of my day with the survey team but also explore other areas of the ship. I have now been onboard for over a week and things are beginning to feel routine. The sun does not set here until about 10:30pm and rises around 6am. Meals are served at regular times and more importantly, at least to me, coffee is available 24/7.
This is TAS Elli’s room aboard NOAA Ship Fairweather at 9:45pm
Mission: Fisheries: Pacific Hake Survey (More info here)
GeographicRegion: Pacific Ocean, off the coast of California
Date: July 13, 2023
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Weather Data from the bridge:
July11 (1200 PT, 1500 EST) Location: 37° 46.7’ N, 123° 26.6’ W 43nm (50mi) West of San Francisco, CA
Visibility: 2 nautical miles Sky condition: Overcast, fog Wind: 20 knots from N 250° Barometer: 1015.2 mbar Sea wave height: 2-3 feet Swell: 6-7 ft from NW 320° Sea temperature: 12.2°C (57.2°F) Air temperature: 12.7°C (57.9°F) Course Over Ground: (COG): 270° Speed Over Ground (SOG): 10 knots
July 12 (1200 PT, 1500 EST) Location: 38° 06.8’ N, 123° 01.6’ W 7nm (8mi) North of Point Reyes Lighthouse, Inverness, CA
Visibility: 2 nautical miles Sky condition: Overcast, fog Wind: 12 knots from N 350° Barometer: 1016.0 mbar Sea wave height: 1-2 feet Swell: 3-4 ft from W 280° Sea temperature: 11.0°C (57.2°F) Air temperature: 11.5°C (57.9°F) Course Over Ground: (COG): 270° Speed Over Ground (SOG): 10 knots
July 13 (1200 PT, 1500 EST) Location: 38° 17.3’ N, 123° 06.1’ W 2.5nm (4mi) Southwest of Bodega Bay, CA
Visibility: 3 nautical miles Sky condition: Few clouds, fog Wind: 13 knots from NW 300° Barometer: 1015.9 mbar Sea wave height: 1-2 feet 1-2 Swell: 3-4 ft from NW 300° Sea temperature: 10.7°C (51.3°F) Air temperature: 13.7°C (56.6°F) Course Over Ground: (COG): 340° Speed Over Ground (SOG): 10 knots
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In my July 6 post, I explained how NOAA Ship Bell M. Shimada is equipped to collect acoustic data in the form of echo grams and therefore find fish to trawl for. In my July 10 post, I explained how we get the fish onboard, and what we do with the sample once it is collected from the net. These entries described what work is done in the Acoustics Lab and the Wet Lab, but there is one more Lab onboard to explore and explain: the Chemistry Lab.
NOAA Ship Bell M. Shimada leaving Pier 30/32 in San Francisco, CA on July 5, 2023. (Just a nice photo taken by me that I wanted to include)
Science and Technology Log
Each morning after breakfast, we usually gather in the Acoustics Lab, determine what transect we are on, if we are inshore or offshore, and in some ways: hurry up and wait. Once certain patterns and blips show up on the echo grams, the Acoustics team talks with the bridge and may request to turn around and attempt a trawl. After all marine mammal observations are completed, the net is retrieved, and the samples are brought to the Wet Lab, we sort and collect data on the samples. These operations usually take place between 0800 and 2000. (8am to 8pm)
So what happens at night? In the Chemistry Lab, scientists work with the Deck and Surveys Departments to deploy a collection of electronic instruments and 12 Niskin bottles (open bottles used to collect and hold water samples, about one meter long) secured to a cylindrical frame called a rosette. It is deployed from the side sampling station instead of the stern. Scientists onboard NOAA Ship Bell M. Shimada use the instruments and collection of water samples in two ways: measuring Conductivity, Temperature, and Depth (CTD) within a water column to study oceanography, and collecting environmental DNA (eDNA).
CTD Niskin bottles arranged on a circular rosette frame.
“Nighttime operations primarily consists of deploying the Conductivity-Temperature [-Depth] (CTD) rosette which gathers oceanographic data such as conductivity, temperature, dissolved oxygen, and chlorophyll fluorescence. The CTD can also be triggered to collect water at specific depths.”
CTD stands for conductivity (ability to pass an electrical current), temperature, and depth. Scientists use the rosette frame, which is attached to the ship by cables, and has the CTD and 12 Niskin bottles attached, to collect electronic data and multiple water samples.
“A CTD device’s primary function is to detect how the conductivity and temperature of the water column changes relative to depth. Conductivity is a measure of how well a solution conducts electricity and it is directly related to salinity. By measuring the conductivity of seawater, the salinity can be derived from the temperature and pressure of the same water. The depth is then derived from the pressure measurement by calculating the density of water from the temperature and the salinity.”
Senior Survey Technician Elysha Agne gives commands to the Deck Department running the winch and cable to the rosette, and ensures quality data is being collected at each sampling depth.
“For more detailed analyses back in the lab, each of the large gray bottles captures a water sample at a different depth. The data provide scientists important information about the local aquatic environment.”
Depending on the depth at which the vessel is currently operating, the rosette will descend to one to five predetermined depths (50m-500m) for sampling. For example, if the vessel depth reads 400m, water samples will occur at 50m, 150m, 200m, and 300m (more information in Table 1 below). A water sample is also taken just below the ocean surface using a through hull fitting, which allows seawater to be collected via a hole in the hull that feeds directly to the Chem Lab.
Table 1 in Protocol manual, written by Chem Lab member and eDNA scientist Abi Wells.
While the rosette descends, data is recorded from multiple sensors and are later used by scientists to compare with Acoustic and Wet Lab data and compile and categorize new information from the survey. Pressure, depth, temperature, conductivity, salinity, oxygen, fluorescence, and turbidity were all being recorded during this leg of the survey mission.
Program displaying data collected from the CTD rosette in real time.
Environmental DNA: eDNA
During the day, Hake stay in deeper waters, averaging around 200-350m, but at night the nocturnal feeders start their daily migration through the water column to shallower depths. They feed primarily on zooplankton, shrimp, myctophids (Lanternfish), and even young Hake at this depth. As Hake move throughout the water column, they leave behind DNA in the water that can be collected later as sort of a signature of their presence in that location. The collection, filtering, and preservation of sampled water in the ocean environment is categorized as collecting eDNA. This environmental DNA can be in the form of gametes (reproductive cells), fish scales, feces, etc.
Collecting water samples at different depths in the same vertical column can show what marine life was present at that location, and what depth they were at. I relate it to reviewing school security cameras or talking to other teachers at the end of the school day, to determine where a student was at a certain time and why.
Chem Lab member and eDNA scientist Abi Wells collecting a 2.5L water sample from a Niskin bottle after a successful CTD deployment.
When the rosette is back on deck, scientists use gloves and new collection bags called Whirlpacks, to collect approximately 2.5L of water from each 10L Niskin bottle. This process is conducted with a great emphasis on sterility, including wiping the bottle spigot with DNAway to remove any contaminants, using new materials, and not allowing fingers or the spigot to touch the collection bag.
Sterile work site being set up to pour water samples into the cups and strain through the filters.Chem Lab member and eDNA scientist Abi Wells pouring a 2.5L water sample into the corresponding cup to strain through the filter.
Once the collection bags are filled and brought to the Chem Lab, filtration occurs using 1.0 micron filters. Although this size of filter, compared to smaller filters, allows some cells to pass through and not be collected, it is faster and results in less breakage of cells and loss of DNA. After 2.5L of the water sample is poured through individual filters for each depth sample, they are placed in pre-labeled (location and depth information) tubes with 2mL of preservative buffer. The tubes are stored at room temperature and away from UV light until NOAA Ship Bell M. Shimada is back in port and the samples can be further researched in on-land laboratories. Results from additional studies help to compile lists of marine life that was present in the water column and can be compared to acoustic data and species caught and logged in the Wet Lab.
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Personal Log
So, there you have it. Three Labs onboard that conduct very different research, but fit together in the puzzle of Hake development, migration, diet, niches, ecosystem, biomass, and supporting sustainable commercial fisheries. Each additional piece of data; whether it be echo sounds, physical samples, eDNA, or CTD information, strengthens the others and helps to create a cohesive summary of the data.
This was a lot to learn in the first few days, but as I’ve said before, all of the crew has been welcoming, supportive, and educational. Having a strong team that works together is priceless, and thoroughly noticed and appreciated.
A few days into the mission my Mom asked me what the best part of my day was. I had three answers and haven’t had a day yet with only one answer. I replied that it was the great salmon dinner, clean clothes, and seeing Risso’s Dolphins for the first time.
Video taken by me of Risso’s Dolphins surfacing for air. (Plays on loop)
We are now a little more than halfway through the mission and it has truly flown by. We’ve shared riddles and daily Final Jeopardy questions. We’ve laughed over daily experiences and the faces Hake fish make. We’ve played music and watched baseball during dinner. We enjoy watching marine life and breathe in the salt air while strengthening our sea legs. Sometimes we just drink coffee and snack and enjoy this opportunity with each other, and that makes every part of the day the best part.
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Did You Know?
Although Hake are occasionally cannibalistic, they are not at the top of their food chain. Humboldt Squid (Remember those 15 foot long tentacles in my Wet Lab post?), Dogfish Sharks, and marine mammals are all predators, as well as commercial fishing. Today well over 100 Spiny Dogfish Sharks were inadvertently caught in the trawl, in the same location as the baskets of Hake we sampled from. Maybe there were baby Hake fish in the sharks’ stomachs… we didn’t attempt to find out.
Basket one of Spiny DogfishBasket two of Spiny Dogfish
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New Terms/Phrases
Although I had learned the terms a few days earlier, I got to help Wet Lab Lead Ethan Beyer collect otolith and stomach samples for the first time from a sub-sample of Hake the other day.
I watched and learned, then helped scan barcodes of otolith sample bottles, add 95% ethanol that is diluted 50/50 with water, and delicately pick up the ear bones with tweezers and place them in the bottle.
Additionally, each Hake in the sub-sample has its weight recorded, along with length, sex, and developmental stage. From that sub-sample, five stomachs are removed for later analysis, and five have their stomachs opened and their diet is recorded. We often find Lanternfish (Myctophids), Krill (Euphausiidae) and small Hake.
Wet Lab Lead Ethan Beyer weighing a Hake sample. Otolith tubes are in the foreground, those with lids have samples inside them and have been scanned into the database with other measurements and samples data from the Hake.
Each day is started and then ended with a water sample from the ocean. The technology is called a CTD, but the procedure would be called a CTD cast (as if we were casting it in the ocean). CTD stands for conductivity, temperature, and depth. The CTD consists of a collection of electronic instruments that measure the properties of the water, including a laser that checks the clarity of the water. Sampling water bottles are connected to a metal frame called a “rosette”. This information on water characteristics is important to both the scientists and the survey mapping team that use cameras and sonar. This information lets them know how well the clarity of the water is and the speed of sound that helps with the depth finders and sonar.
CTD used to check water quality, conductivity, temperature, and depth.
Vocabulary Check
What is Conductivity?
Conductivity is a measure of the ability of water to pass an electrical current.
What is Salinity?
Salinity is the dissolved salt content of a body of water and is a strong conductor of water.
So why is it important for scientist to know what each of these are?
The higher salinity the water is, the higher the conductivity of electrical currents.
Temperature also plays a role in the density. Knowing each of these is important because it lets the scientists know the water quality at different depths so they can make adjustments to their cameras and sonar.
Jack Prior, Chief Scientist
Jack is a pretty “chill” guy, and I have enjoyed watching him in action the past few days. Jack is the field party chief of this mission which involves everything from planning the trip, to deciding the daily sampling locations, deploying cameras, mapping, and figuring out what to do when things go wrong. Jack is in charge of planning and submitting the protocol for the entire mission and also is responsible for the end reports of the mission. You will find Jack on this leg sitting behind multiple computers regulating and keeping a watchful eye on all of the important information regarding this mission. Jack attended the University of West Florida to get his degree in marine biology.
Chief Scientist Jack Prior
Student Question of the Day
Whenever I get a chance, I ask random crew members questions that my students back home were curious about. Here is how Jack answered some of the students’ questions.
Konnor, Nichole, Lillian ask: What degree do you have and what all is needed to do your job?
Jack started his major in biology and had originally planned on going on to be a pharmacist, but then moved to Florida where he ended up getting his degree in marine biology instead. Jack continued to also get his Masters at the University of West Florida, too. Jack changed his career path because he enjoyed marine life. Volunteer work is crucial to get experience, and can benefit you on becoming more diverse when it comes to getting a job in marine biology.
Alyson asks: What would be your dream job?
Someday Jack wants to explore the seafloor in a submarine.
Blake, Sailor, Lilli, Jenna ask: What is your favorite food on the ship?
Taco Tuesdays seem to be a huge hit on the ship, as well as Friday pizza day.
Auburn, Ashton M., Karson, Liam: What would you consider to be the coolest marine life you have seen?
Seeing large diverse reef habitats is what Jack says he finds the most interesting, especially uncommon invertebrates that you’d never see on the beach.
Jaxon and Dwight: Can you be on the ship if you have health issues and what happens if there is a medical emergency?
The ship is a pretty confined space with steep stairs, uneven footing, areas you have to be able to step over, and have the ability to carry heavy weight. If there is ever a medical emergency, the ship works alongside the United States Coast Guard to get them the help they need. However, the ship is great working with all issues and plans accordingly to those who may have special diet restrictions.
Personal Log
Well, I will say that I am getting better at having my sea legs but that is still a work in progress. I have really enjoyed getting to understand the life on this ship, and I am just amazed at how diverse everyone is and yet still make this an amazing environment. It has taken me a few days to get the hang of where things are and to get out of my comfort zone to ask what I feel like has to be a million questions about everything. I have really enjoyed getting to hear and learn about the crew’s background and how they ended up on NOAA Ship Pisces. I greatly appreciate their willingness to answer my questions, even though I am sure I am in their way at moments. Everyone has a job to do and work different hours and shifts. It is great to see how they all respect each other’s space and sleeping hours.
There is so much science around me that I never knew existed, and I am shocked on how much technology is actually being used and heavily relied upon. Today was the first day the waves were calm enough that I was able to go out on the stern (learning names of different areas of the ship) to work on the blog and soak up a little bit of Sun. It was nice to be able to get some fresh air. The food has been amazing on the ship. I love how everyone is so courteous by thanking the cooks, as well as cleaning up after themselves before leaving the mess. The mess is the area in which we eat and the kitchen is called the galley. It has taken me a few days to understand the boat “lingo” but I am starting to catch on. The stairs are pretty steep, and everyone on board says to use 3 points of contact when walking. This is so that if they hit a wave while walking you are more stable. I could definitely see this being an issue going up and down the stairs. The doors are super heavy and I am still learning how to get those twisted and sealed tight the first time I close it (I am getting there).
The mess where we eat. It is spotless and a great size to fit everyone on board.
In this post, I would like to walk you through my interactions and observations with the science research being conducted aboard the R/V Tommy Munro, in particular, the steps that were taken during a trawling process. The entire process involved three stages: Preparing for Sampling, Conducting the Sampling, and Analyzing the Sampling with each stage consisting of six distinct steps.
Step 1: The ship travels to designated coordinates for sampling sites as determined for the particular leg of the Survey by SEAMAP (Southeast Area Monitoring and Assessment Program).
Ship Transport to Sampling Site
Step 2: Once the ship reaches the site, a Secchi disk is attached to a cable and lowered into the water off the side of the ship to determine visibility. When the disk can no longer be seen, the depth is recorded and the disk is raised and secured on ship.
Deployment of Secchi Disk
Step 3: A CTD (Conductivity, Temperature, and Depth) unit is then prepared for deployment. It is a rectangular chamber with sensors designed to measure physical properties of the water below including dissolved oxygen, conductivity, transmissivity, and depth.
Preparation of CTD Unit
Step 4: The CTD unit is powered on and first is submerged just below the surface of the water and left there for three minutes for sensors to calibrate. It is then lowered to a specified depth which is 2 meters above the floor of the body of water to protect the sensors from damage.
Deployment of CTD Unit
Step 5: Once the CTD unit has reached the designated depth, it remains there only for seconds until it is raised up and secured on board the ship.
Recovery of CTD Unit
Step 6: The CTD unit is then turned off and the unit is connected through a cable to a computer in the dry lab for data upload. Once the data upload is completed, the CTD unit is flushed with deionized water using a syringe and plastic tubing and then secured on the side of the ship.
Data Upload from CTD Unit
II. Conducting the Sampling
Step 1: The trawling process now begins with the trawl nets thrown off the back of the ship. The nets are connected to two planks, each weighing about 350 lbs, which not only submerges the nets but also provide an angled resistance which keeps the nets open in the form of a cone – optimal for sampling while the ship is in motion.
Preparation of the Trawling Process Part 1
Preparation of the Trawling Process Part 2
Step 2: Once the trawl nets have been released into the water from the ship, the ship starts up and continues on its path for 30 minutes as the nets are trapping marine life it encounters.
Onset of the Trawling Process
Step 3: After 30 minutes has transpired, a siren sounds and the ship comes to a stop. The two weighted planks are pulled upon the ship followed by the trawl nets.
Conclusion of the Trawling Process Part 1
Conclusion of the Trawling Process Part 2
Step 4: The trawl nets are raised and hoisted above buckets for all specimens to be collected. Then begins the process of separation. In the first separation, the marine life is separated from seaweed, kelp and other debris. The buckets with marine life and debris are then weighed and recorded.
Content Collection from the Trawl Part 1
Content Collection from the Trawl Part 2
Step 5: The bucket(s) with marine life are emptied upon a large table on the ship’s stern for separation according to species.
Separation Based on Species Part 1
Separation Based on Species Part 2
Step 6: Each species of marine life is placed in their own tray for identification, examination, and measurements inside the wet lab.
Species Sorted in Trays Part 1
Species Sorted in Trays Part 2
III. Analyzing the Sampling
Step 1: After all species were grouped in their trays, all trays were taken into the wet lab for analysis. Each species was positively identified, counted, and recorded.
Tray Transport to Wet Lab
Step 2: Once each species was identified and counted, the total number of species was weighed while in the tray (accounting for the mass of the tray) and recorded on a spreadsheet to a connected computer display system.
Total Weight Measurements
Step 3: For each species, the length of each specimen was recorded using a magnetic wand with a sensor that facilitated the electronic recording of the value into a spreadsheet.
Individual Length Measurements
Step 4: Weights of the collected species were recorded for the first sample and every fifth one that followed.
Individual Weight Measurements
Step 5: If time permitted between samplings, the sex of selected specimens for a species was determined and recorded.
Individual Species Sex Identification
Step 6:Once the entire sampling was analyzed, selected samples of specimens were placed in a baggie and stored in a freezer for further analysis with the remaining specimens returned to a larger bucket and thrown overboard into the waters. The separation table was cleaned with a hose and buckets were piled in preparation for the next sampling.
Finalize Process and Prepare for Next
In this installment of my exercise of the Ocean Literacy Framework, I would like to ask you
to respond to three questions about the fifth essential principle (The ocean supports a great diversity of life and ecosystems.), presented in a Padlet accessed by the following link:
Remember, there are no right or wrong answers – the questions serve not as an opportunity to answer yes or no, or to get answers right or wrong; rather, these questions serve as an opportunity not only to assess what you know or think about the scope of the principle but also to learn, explore, and investigate the demonstrated principle. If you have any questions or would like to discuss further, please indicate so in the blog and I would be glad to answer your questions and initiate a discussion.
La línea hidrográfica de newport es un estudio de investigación oceanográfica realizado por científicos del Centro de Ciencias Pesqueras del Noroeste de NOAA y de la Universidad Estatal de Oregón en las aguas costeras de Newport, Oregón .
Los investigadores han recopilado métricas oceanográficas físicas, químicas y biológicas a lo largo de Newport Line cada dos semanas durante más de 20 años. Este conjunto de datos de más de veinte años nos ayuda a comprender las conexiones entre los cambios en el clima oceánico y la estructura y función del ecosistema en la corriente de California1,2,3.
Los datos de Newport Line se destilan en indicadores de ecosistemas oceánicos , que se utilizan para caracterizar el hábitat y la supervivencia de los salmónidos juveniles, y que también se han mostrado prometedores para otras poblaciones como el bacalao negro, el róbalo y la sardina4. Estos datos también brindan información crítica del ecosistema sobre problemas emergentes, como las olas de calor marinas3, la acidificación de los océanos, la hipoxia6 y la proliferación de algas nocivas7.
Newport line
Barómetro de la acidificación e hipoxia de los océanos en un clima cambiante
Los modelos climáticos globales sugieren que los cambios futuros en el afloramiento costero conducirán a una mayor incidencia de hipoxia y exacerbarán aún más los efectos de la acidificación de los océanos. La serie temporal de Newport Line proporciona una línea base de parámetros biogeoquímicos, como el estado de saturación de aragonito, un indicador de condiciones ácidas (Fig. 4). Los investigadores pueden comparar esta línea de base con posibles cambios futuros en la abundancia de organismos (p. ej., pterópodos, copépodos y krill) sensibles a la acidificación del océano y la hipoxia.
Equipo utilizado
Red vertical
Colocando la red vertical en el agua
red vertical desplegada verticalmente en el agua desde un buque de investigación
Una red vertical es una red de anillos con un ancho de malla pequeño y una forma de embudo largo. Al final, la red se cierra con un cilindro (copo) que recoge el plancton. Se despliega verticalmente en el agua desde un buque de investigación. Se utiliza principalmente para investigar la estratificación vertical/diagonal del plancton. Esto permite determinar la abundancia y distribución del mesozooplancton.
Red de bongó
Lavado de la muestra por la red bongó
Un barco de investigación tira horizontalmente de una red de bongo a través de la columna de agua.
Una red bongó consta de dos redes de plancton montadas una al lado de la otra. Estas redes de plancton son redes de anillos con un ancho de malla pequeño y una forma de embudo largo. Ambas redes están encerradas por un copo que se utiliza para recolectar plancton. Un barco de investigación tira horizontalmente de la red bongo a través de la columna de agua. Usando una red bongo, un científico puede trabajar con dos anchos de malla diferentes simultáneamente.
Asistiendo a Toby con la red Isaacs-Kidd
Red Isaacs-Kidd
Dimensiones de la red Isaacs-Kidd
La red de arrastre de media agua Isaacs-Kidd recolecta especímenes biológicos batipelágicos más grandes que los capturados por las redes de plancton estándar. La red de arrastre consiste en una red específicamente diseñada unida a una amplia paleta de buceo rígida en forma de V. La veleta mantiene abierta la boca de la red y ejerce una fuerza de presión, manteniendo la red de arrastre en profundidad durante períodos prolongados a velocidades de remolque de hasta 5 nudos. La abertura de entrada no está obstruida por el cable de remolque.
Muestras recolectadas
Muestras de red verticalMuestras de red bongó
Muestasas de Isaacs-Kidd
Kril recolectado de Isaacs-Kidd
Registro personal
¡ATAQUE DE TIBURÓN!
Así es, nuestro uCTD fue atacado por un tiburón.
Q.D.P.
En un día brillante y soleado, el equipo científico decidió lanzar el CTD en curso, ¡pero las cosas no salieron según lo planeado! Al recuperar el uCTD de regreso al barco, vimos una gran aleta dorsal zigzagueando cerca del uCTD, hasta que notamos que el uCTD ya no estaba conectado a la línea, por lo que no tuvimos más remedio que cancelar el uCTD. Deberías haber visto todas nuestras caras; no podíamos creer lo que vimos. Creemos que podría haber sido un:
Tiburón BlancoTiburón Salmon
uCTD (lo que se comió el tiburón)
CTD significa conductividad (salinidad), temperatura y (Depth) profundidad y permite a los investigadores recopilar perfiles de temperatura y salinidad de la parte superior del océano a velocidades en curso, a profundidades de hasta 500 m. Los exploradores oceánicos a menudo usan mediciones CTD para detectar evidencia de volcanes, respiraderos hidrotermales y otras características de aguas profundas que causan cambios en las propiedades físicas y químicas del agua de mar.
