- Deep Sea Fauna
- Environmental Variability
- Consequences of DWHOS
- Student Research
- DEEPEND Publications
Hello, my name is Max Weber and I am a Masters candidate in Marine Biology at Texas A&M University at Galveston. I study deep-sea fish genetics in the lab of Dr. Ron Eytan. Genetics are a powerful tool that can reveal a lot about the fishes that inhabit the deep-sea. One of my areas of research involves the investigation of population size over time in a large number of deep-sea fish species.
We used to think that even though sea surface temperatures change a lot day to day and season to season, that deep-sea temperatures were very stable (cold, but stable!). However, recent long-term monitoring studies have shown evidence of rapid alterations in deep-sea temperatures and other studies on benthic deep-sea communities have shown that those communities are currently being altered as a result of climatic changes.
Historic changes in population size (the number of individuals of a given species in a population) often reveal the effects of major ecological events on the genetic diversity of a population or a species. These fluctuations can be inferred through the use of molecular data. Global climate conditions have varied greatly since the last glacial maxima, approximately 20,000 years ago, leading to changes in global currents, oceanic temperatures, and sea level. Several studies have recently uncovered sharp declines in population sizes of coastal marine fishes attributed to these changes in the marine environment.
My Master’s research focuses on whether fluctuations in the population sizes of deep-sea fishes mirror those found in coastal/shallower water. If I find evidence of recent population expansions in deep-sea fishes, it would suggest that the deep-sea environment is more volatile than previously imagined, however, if I find that the populations of deep-sea fishes are stable, it would suggest that the environment is stable as well. To answer this question, I am using several different methods of analysis to look at DNA sequence data. One method is the Extended Bayesian Skyline Plot (see example below). This presents a visual representation of population size going back in time. Some of my preliminary analyses have revealed major population expansions in recent history. These are exciting results and may help to give us a better idea of how the deep-sea habitat has changed over time.
This is a photo of the lovely hatchetfish, Argyropelecus aculeatus, which lives between 300-6,000 feet deep. It is one of the most common species we capture on our cruises.
This is an Extended Bayesian Skyline Plot (EBSP) showing the population size of Argyropelecus aculeatus over time. It shows that the population had a major expansion followed by continued growth. I am currently working to calibrate a molecular clock that will allow me to assign dates to these changes.
This is a deep-sea dragonfish, Echiostoma barbatum, collected during one of the DEEPEND cruises.
Howdy! My name is Corinne Meinert and I am a Master’s student in marine biology at Texas A&M University in Galveston studying biodiversity of ichthyoplankton in the Northern Gulf of Mexico. When you break the word ‘ichthyoplankton’ down you get ‘ichthyo’ which means fish, and ‘plankton’ which means drifter, so all together the word refers to fish eggs and larval fish that drift in the ocean with the currents. Studying the biodiversity of these little fish is important because it can tell us how healthy the ecosystem is where they live; in general, the higher the diversity of fish, the healthier the ecosystem.
To give you an idea of how small these fish are, below is a picture of a snake mackerel (Gempylus serpens) on my finger:
In the lab, we use microscopes to visually identify our fish samples to the family level. For some families, such as tunas, billfish, and dolphinfish, we use genetics to identify the fish to species level. Over the past two years, we have collected and identified over 18,000 larval fish and have found a total of 99 different families. The most abundant families we have found are lanternfish (Myctophidae) and jacks (Carangidae), when combined, these two families make up of 25% of our total catch. Below are a few pictures of different families of fish we have collected (note: the third one is a tuna with another tuna inside of its stomach!):
We still have a lot to learn about larval fish. Understanding how abundant they are and where they live can help us make better management decisions for the future. If you want to learn more about ichthyoplankton and biodiversity, here are a few good webpages and videos to get started:
Information on ichthyoplankton: https://swfsc.noaa.gov/textblock.aspx?Division=FRD&id=6210
Information on biodiversity: https://www.youtube.com/watch?v=GK_vRtHJZu4
A compilation of other fish (and one invertebrate!) caught during DEEPEND sampling:
Blog by Sebastian Velez, Master's Student at Wilkes Honors College, Florida Atlantic University, Jupiter, FL
When you walk into a restaurant and order sushi, or a fish dinner, do you ever contemplate the series of events that led to that fish arriving onto your plate? Probably not…you’re hungry, but the odds that that particular animal would make it to a harvestable size are astounding. I’ll give you an example. A 10-year-old red snapper in the Gulf of Mexico can produce approximately 60million eggs annually. Of those 60 million eggs, only 450 individuals will reach a size of 5cm. At this size they are still susceptible to predation, starvation, and advection away from suitable habitats. My name is Sebastian Velez and I’m a Master’s student in Biology at Florida Atlantic University, studying juvenile snappers and groupers in the Northern Gulf of Mexico collected during the DEEPEND Cruises. I am particularly interested in what happens to these organisms when they are wafted far out to sea, off the continental shelf in areas where depths can reach 1500m.
This is a juvenile Red Snapper, Lutjanus campechanus. This species supports multimillion dollar recreational and commercial fisheries in the Gulf of Mexico.
Now this concept of advection away from suitable habitat is something that occurs as a result of the life history of snappers and groupers. Both families form seasonal spawning aggregations, at which point the resulting larvae are wafted out to sea for 20-50 days, and begin settling on nearshore habitats. The currents responsible for this dispersal include; the Mississippi River Discharge Plume, The Loop Current, and a series of cyclonic and anticyclonic eddies. But every once in a while these larvae get wafted a bit too far offshore. Literally hundreds of kilometers away from their preferred habitats and so the question is; what happens to these animals when they are so far from shore?
The literature is very vague as to what happens with these expatriates, with most accounts only stating that this phenomena takes place and they most likely die as a result of starvation or predation. Thanks to the DEEPEND cruises, we have found that the biodiversity of these expatriates within both families was impressive, with some of the most notable species being; Goliath Grouper, Snowy Grouper, Nassau Grouper, Red Snapper, Vermillion Snapper, Grey Snapper, and Queen Snapper. Our study also suggests that a few members within these families have the ability to stall their settlement, specifically the Wenchman snapper. Individuals were often found ranging from 14-47mm in standard length, lengths usually attributed to newly settled individuals. We also found new depth records for Red and Wenchman Snapper down to 1500m, well past their normal distributions, most likely in an attempt to find suitable habitat where none exists.
This is an unidentified member of the Subfamily Liopropomatinae, Liopropoma sp. Another type of grouper with vivid colorations and often referred to as basslets, these are very popular in the aquarium trade.
These fishes represent multi-million dollar industries in the form of commercial and recreational fisheries. Understanding the biology and life history of exploited species is imperative in informing future management decisions. The pelagic stages of these species have historically been very hard to sample, thus leaving a gap in the associated knowledge. The processes by which these individuals are dispersed represent a potential mechanism in the connectivity between populations and could help managers forecast future drops in stock abundance.
An unidentified individual from Subfamily Epinephilinae. These are your classic groupers. Examples would be Nassau and Goliath Groupers.
Written by Rosanna Milligan
It’s the end of another successful cruise and we’ve collected thousands of animals and taken hundreds of physical and chemical measurements across the northern Gulf of Mexico. My job is now to take these data, integrate them with the data from our previous research cruises, and analyze them all to try to find patterns in them that will help us understand how the deep pelagic fish communities are structured.
Understanding how animals are distributed through different environments is one of the key questions in ecology, because the answers can tell us important information about which areas might be particularly valuable. This might be because they contain particularly high biodiversity and are important to conserve, or they might be areas that might contain particularly high abundances of animals that we might want to target for fisheries or drug development for example.
While it’s easy to imagine different terrestrial environments, like deserts, forests or mountain ranges, it’s much harder to imagine what the different environments that might exist in the open oceans are, because, frankly, one patch of seawater looks much the same as any other at first glance. But, when we start looking with scientific instruments like CTDs, or using satellite imagery, we can start to see how the oceans are structured by gradients and boundaries in the physical and chemical properties of the oceans like temperature, salinity or water currents. However, we still don’t really understand is how much this environmental variability influences the animals that live in the deep pelagic oceans. Do they care about different conditions or are they happy to live anywhere? Are they just pushed around randomly by water currents or do they actively swim against them to stay in the best locations?
CTD Instrument used to measure the physical properties of water and to collect water samples from different depths.
Our work with the DEEPEND project is starting to disentangle some of these ideas. For example, we’ve been working hard to figure out how to identify different water masses in the Gulf of Mexico in an ecologically-meaningful way, and separate out how and why different water types affect different deep-sea animals and their distribution patterns. We’re working with teams of geneticists, chemists and oceanographers too, to match up all the different research strands into a coherent story. All of this will be really important in understanding how resilient or vulnerable different organisms might be to human impacts in the Gulf of Mexico, in case something like the Deepwater Horizon disaster ever happens again.
So all the work we do at sea is really just scratching the surface of the work we do when we get back. We’ve got lots more work to do and many more questions to answer!
Written by Tess Rivenbark
My name is Tess Rivenbark and I am representing the Optical Oceanography Lab at the University of South Florida College of Marine Science. Most of the scientists here focus on biology, but my job is to collect data that ties this biology to the physical processes happening in the ocean, looking at different types of particles in the water.
With the CTD, I collect water samples and then filter them to measure chlorophyll and colored dissolved organic materials. Here is a picture of the CTD as it is being deployed from the ship. We send it down to 1500 meters collecting water samples along the way at various depths and measuring the physical properties of water such as temperature, salinity, and dissolved oxygen.
Another instrument I use, a spectral backscattering sensor, is known to the other scientists as the "fish disco" because it emits multi-colored lights. It measures how these lights bounce, or scatter, off of particles in the water.
My last instrument, a handheld spectral radiometer, measures the sunlight that reflects off the water. This is the same thing that many satellites orbiting the earth, like the Aqua MODIS, are measuring. We use the data we collect out here on the water to help understand what the satellite measurements tell us about the particles in the water. The two photos below show this instrument in use at sea and below that is a satellite image showing the concentration of chlorophyll with our proposed cruise track and sample stations plotted on top.
Written by: Matt Woodstock – DEEPEND graduate student, Nova Southeastern University
Hello, my name is Matt Woodstock and I am a graduate student at Nova Southeastern University working with the DEEPEND Consortium. This is my first time on a research cruise and I wanted to share a bit of my experience so far. Our ship, the R/V Point Sur, is equipped with all the supplies we need to do our science.
Pictured here (Left to Right): Gray Lawson (Technician), Joe Lopez, Travis Richards, Laura Timm, Tracey Sutton, Jon Moore, and Rosanna Boyle
My job aboard the ship is to help Travis Richards (PhD student at Texas A&M Galveston) pull tissue samples for genetic sequencing. An average day for us begins early in the morning, hauling nets in from the tow the night before. We sort through each sample, dividing the fishes, crustaceans, squids, and jellyfishes.
Pictured here (Left to Right): Tammy Frank, Tracey Sutton, Mike Vecchione
After being identified by our experts, the animals are measured, weighed, and organized so they can be sent to different labs that study each species. We are currently freezing animals for stable isotope analysis, polycyclic aromatic hydrocarbon (PAH) analysis, and parasite analysis (my thesis study).
A Red Velvet Whalefish, Barbourisia rufa, caught between 600-1000 m that was sampled for stable isotope and genetic sequencing
Three Helmet Jellyfish, Periphylla periphylla, caught in an oblique tow (0-1500 m) is a deep-sea bioluminescent jellyfish
Other animals are persevered and sent to several different labs for later studies. We do this twice a day (day and night) and observe differences in the distribution of animals on a diurnal cycle. Occasionally we will take a break from our sample processing to see anything cool happening on the deck. This morning, we saw the sunrise.
Well, our first day of sampling was a success! We managed to deploy the MOCNESS twice at Station B081 (check out our home page to follow the ship!). While retrieving the night trawl we saw a lot of bioluminescence in the water which turned out to be pyrosomes, Pyrosoma atlantica, seen in the picture below. Each pyrosome is a colony of animals called tunicates which related to sea squirts. They form a tube which can pump water to allow them to vertically migrate. The longest species of pyrosome can get up to 20 m in length! We also saw some flyingfish which were being chased and eaten by dolphins!
Today we continued on to B082 and completed two additional successful trawls. Below are some images from the team processing the catch.
Here several of us are emptying the codends and sorting the catch.
Once we've sorted the catch, our team of taxonomic experts identify each organism to species. From front to back we have Dr. Tracey Sutton, Nova Southeastern University who specializes in fish identification, Dr. Jon Moore, Florida Atlantic University who also specializes in fish identification, Dr. Tammy Frank, Nova Southeastern University who specialized in shrimp identification, and last but not least, Mike Vecchione, NOAA's National Systematics Lab specializes in squid identification.
Here, Laura Timm, PhD student at Florida International University takes the species identified by Dr. Frank and samples them to run genetic analyses back in her lab after the cruise.
Travis Richards (foreground) is a PhD student at Texas A&M Galveston whose research involves stable isotope analysis, however, on this cruise he is taking tissue samples for the fish genetics team with the help of NSU graduate student, Matthew Woodstock (middle). I'm at the end of the line in this picture measuring fish lengths.
Our DEEPEND mascot, Squirt, hangs out with us in the lab making sure we're doing our job! You'll see more of him this week on instagram - @deepend_gom
The acoustics team have detected some very large animals under the ship. They will be blogging all about their new gear and what they are "seeing" with sound later this week!
Thank you for following our blog and stay tuned for more!
by Mike Vecchione
We are at sea. We finally got under way at 11:00 last night. We were ready at 9 PM but had to wait for two container ships to come in and get safely docked before we could go past them. One belonged to Dole and the other to Chiquita. Both were loaded with bananas. We literally had to wait for a couple of banana boats!
We made good time last night because the wind came around astern and we surfed our way out here. "Here" is almost at our first station and quite close to the wreck of the Deepwater Horizon. Seas have been running 6-8 ft (moderately unpleasant) but now they are beginning to settle down and we should be able to begin sampling this evening. We are finally out in Sargassum and water that you can see through, a big contrast with Gulfport. There was a dolphin feeding in the lights of the ship before we left and you could not see it until it broke the surface. We are surrounded by huge oil rigs in the distance. There is an support ship practicing with its very impressive water cannons for fighting fires on the rigs. There are flying fishes around but most of the birds I have seen are land birds that were blown offshore by the storm. We are all looking forward to working tonight.
Figure 1. Screen shot of the ship's navigation computer, showing oil rigs around our location.
Figure 2. Water cannons from a oil-rig support ship, presumably a fire-fighting drill.
We spent part of Friday getting the lab set up and everything tied down, the acoustics group moved their heavy gear onboard and worked feverishly to get everything connected, our MOCNESS tech got the MOCNESS frame put together so that we could attach the nets, all in time for a Friday night departure. And …… here we sit. The winds are howling, and we have whitecaps (little waves) in the harbor. What howling winds and whitecaps in the harbor mean is 10-15 foot waves and even stronger (perhaps shrieking) winds on the open ocean. Our options were to try and get out anyway, spend three days bouncing around in horrible weather with most of the scientific party seasick, and finally completing the 20 hour transit in 60 hours for an early evening arrival on station Monday night, or spending several days at the dock, leaving Sunday night, and spending 20 hours transit for an early evening arrival on station Monday night. Being scientists, we of course considered the pros and cons of each option, and since option 1 had no pros, we settled on option 2.
Written by: Dr. Tammy Frank
As I was preparing for our next research cruise I received a very exciting letter in the mail! In fact, it was more than just a letter…it was Flat Stanley! (http://www.flatstanleybooks.com/) He wants to join us on our research cruise. How could I say no? He travels light, does not take up much space, and will not require any extra food! Better yet, he has decided to join us in the van while we drive the gear from Dania Beach, FL to Gulfport, MS where the RV Point Sur is docked. It will be good to have him out there with us to show him all of the cool shrimp, squid, and fish that we collect. If we happen to lose any of our tools in tight spaces he will be able to fish them out for us! We’ve set him up with his own blog profile so that he can blog about his experiences with you guys! So keep checking the Kids blog between April 27th and May 14th to learn about his first official deep-sea cruise!
Blog posted for Jeff Plumlee:
Howdy from the Blazing Seven!
Success! We have completed our mission, with all gear intact, and two days ahead of schedule. We finished 12 stations today towing both the neuston and bongo nets. Our day started at station 37 at 06:00 hours and finished at 21:00 at station 48. Sargassum mats were still very present throughout the day but diminished towards the end. The majority of the fishes we had found in previous trawls, however, a few fish expanded our list of families, such as porcupinefish (Diodontidae) and pipefish (Syngnathidae). We continued to find billfish and flying fish larvae when sorting through the Sargassum mats.
Another group of people, aside from the scientists, that needs recognition for our success is our crew. Warm meals, posh rooms, and a fully functioning vessel, all are attributable to the hard work of the crew of the Blazing Seven.
Thomas Tunstall - Captain
All of them played many different roles throughout this trip, and all of them have put forth their best efforts to get us home safe and sound. Thanks again guys.
Well, this is my last update. We head home to Galveston, TX tomorrow morning with samples in hand. Stay tuned for our second ichthyoplankton cruise in July - we can only hope that it goes as smoothly. Cheers!
Blog posted for Jeff Plumlee:
Howdy from the Blazing Seven!
Day three turned out to be another beautiful day to be a scientist on the Blazing Seven. Flat seas, blue water, and warm sun have been a constant this trip, to our enjoyment. We began our day after making the trip from N 27 to N 28 and arriving at station 25 at 0600. Sargassum was yet again present in every tow save the last two and brought a bounty of fishes. It was the most we had seen yet, but with some new faces, including tripletail (Lobotidae) and Bermuda chub (Kyphosidae). We continued to find billfish larvae as well as flying-fish larvae. Our last two sites had an amazing amount of diverse larvae from families like Bothidae, Carangidae, and Synodontidae. We are hoping this exciting trend continues!
One of the important, sometimes overlooked, aspects of any expedition is the hard work of the field researchers that help to collect the enormous amount of specimens and data. Today's post is about recognizing the folks out here keeping the wheels turning.
PhD Student Larissa Kitchens
Graduate Technician Carlos Ruiz
Undergraduate Technician Chris Steffen
Undergraduate Technician Josh Bowling
Undergraduate Volunteer Jason Williams
Without these students and technicians putting forth their best efforts and working together as a team, these projects would run far less smoothly.
Tomorrow we hit the last leg of our journey, Stations 37-48, followed by our trip back to Port Fourchon. It's been fantastic so far but there is still a good deal of sampling left to do, so stay tuned!
Blog posted for Jeff Plumlee:
Howdy from the Blazing Seven!
Today was another rousing success with an early 500-m midwater trawl at 04:00 followed by our 13th station at N 27 W 89 36' at 06:00. Our midwater trawl consisted of shrimp, squid, jellyfish, and of course, lanternfishes (Myctophidae). It was another beautiful day with clear blue water, a gentle breeze, and 1 - 2 foot seas. We progressed through twelve stations today and continued to have Sargassum at every one. However, with Sargassum, comes abundant diversity, including filefishes (Monacanthidae), triggerfishes (Balistidae), Sargassum fish (Antennariidae), flyingfishes (Exocoetidae), dolphifishes (Coryphaenidae) and others, along with shrimp and crabs. We also found several billfish and flyingfish larvae as well in our neuston and bongo nets.
juvenile flying fish
One of our primary objectives on this cruise is to collect ichthyoplankton, primarily billfishes of the families Istiophoridae and Xiphiidae, tunas of the family Scombridae, dolphinfishes (Coryphaenidae) and flyingfishes (Exocoetidae). Dr. Jay Rooker from Texas A&M University at Galveston and many of his students utilize larvae and samples collected from these trips to create a better understanding of these pelagic fishes. Through the utilization of techniques such as otolith chemistry and genetics, along with the collection of oceanographic parameters, researchers can understand in detail the life history of these fishes as well as habitat preference, spawning locations, and population structure. Continued quantitative sampling using multiple gear types, with replicated sampling, allows detailed analysis over seasons and years, revealing long-term trends which are crucial to understanding pelagic ecosystem patterns.
Tonight we are making the trip from N 27 to N28 to begin our second leg of the trip, the westward transect back towards Port Fourchon. We have finished our last midwater trawl so sampling begins tomorrow at 06:00 with neuston and bongo net tows, so stay tuned for more updates!
Blog post from Jeff Plumlee on the Blazing Seven:
Howdy from the Blazing Seven!
We have had an incredibly productive day! This morning we woke up at 0300 as we arrived on our first site at N 27 W 91. Shortly after, we completed our first 500m mid-water tow with a ring net. In the tow we collected several deepwater species including, lanternfish (Myctophidae), deepwater shrimp, and various fish larvae. After the 500m tow we rested and prepared till 0600 to start our first site for neuston and 100-m bongo nets tows looking for billfish and tuna larvae. The most abundant feature of today was Sargassum, and there was plenty of it, a pattern we are very familiar with in Galveston, Texas. However even with the Sargassum we were able to find plenty of jacks (Carangidae), f ilefish (Monacanthidae), and a good number of flyingfish larvae, among other pelagic species. Despite the potential setbacks Sargassum can cause, we were able to complete 12 sites from N 27 W 91 to N 27 W 89.5 which, according to Captain Thomas, is a TAMUG Billfish cruise record for site sampling productivity, WHOOP!
In addition to towing nets, we also filtered water at several select stations to help aid fellow researchers at TAMUG. Dr. David Wells of Texas A&M at Galveston, and his soon-to-be PhD student, Travis Richards, are focusing their efforts as apart of the DEEPEND Consortium on pelagic organisms and their trophic connectivity. One way that this can be accomplished is through stable isotope analysis. Looking at the ratio of heavy isotopes (Carbon 13 and Nitrogen 15) can help researchers understand the contributions to an organisms' diet. Specifically, contributions from primary production (using Carbon 13), and trophic position (using Nitrogen 15). Gathering the contributors of the base of the trophic web as well as the estimates of their associated locations and oceanographic features is crucial to applying effective models to the system. That's where we come in. Filtering water and analyzing the phytoplankton collected in the filter, along with collecting vegetation from the site (like Sargassum) is an easy way to create these regional maps and is crucial to understand food web dynamics.
Tonight we will complete our second 500-m mid-water tow, and tomorrow we hope to finish our N 27 transect as well as a third 500-m mid-water tow. We are continuing to run into new and dynamic oceanographic features, so stay tuned for updates!
After a few delays and a change in available crew, the Blazing Seven is back in action! I am unfortunately not out there with them, but I will be posting blogs and updates on the cruise tracker for them. Jeff Plumlee, a researcher from Texas A&M Galveston, will be sending us updates from sea. Unfortunately, they will not be able to send pictures or videos during the cruise, but we will post some in our picture gallery after they get back. Here is the first blog from the Blazing Seven!
Jeff Plumlee, Shark Biology and Fisheries Science Lab, Texas A&M Galveston
Howdy from the Blazing Seven!
This morning, at approximately 0700 hours, The Blazing Seven left from Port Fourchon, LA with six Texas A&M at Galveston student researchers, and four Blazing Seven crew members, to begin our first Ichthyoplankton cruise looking for billfish and other pelagic fish larvae. This research team is conducting this survey as part of the GOMRI initiative as members of the DEEPEND Consortium to study pelagic fish ecology and trophic connectivity. This is our second attempt at the cruise after being stalled on June 1st due to a mechanical malfunction, but after some repairs, we're back! Today was designated primarily as a travel day, as it will take us about 20 hours to arrive at our first site, but we were still able to start collecting data.
Dr. Kevin Boswell and his Research Technician Adam Zenone, of Florida International University, have equipped the Blazing Seven with three separate SONAR transducers that they will use to monitor the DSL (deep scattering layer). The DSL is a layer of fish and zooplankton that gather at between 300 and 500 m depth during the day, and within the top 200 m at night. This mass aggregation of fishes can cause an anomaly in SONAR estimates of depth, due to the sound bouncing off of the many fishes' swim bladders, and represents a very large amount of biomass in the open ocean. Dr. Boswell will use the information gathered on the cruise to observe the intricacies of the DSL, as well as the diel vertical migration of fishes and zooplankton, and use these techniques to better understand the ecology of deepwater ecosystems.
Today we were able to deploy these three transducers as well as calibrate them for our six-day cruise throughout the Gulf collecting several cycles of the movement of the DSL. We also were able to get our first glimpse of pelagic fishes! Jacks, Tuna, Mahi, and Flying Fish galore, along with a very curious Silky Shark that was attracted to the calibration device we used for the SONAR transducers.
Tomorrow morning we start very early with our first nighttime deep water tow using a ring net at 500m. So make sure to stay tuned for what we find!
We have had some questions come in about the MOCNESS that we are using to collect our deep-sea animals. “MOCNESS” is an acronym for a Multiple Opening/Closing Net and Environmental Sampling System and it comes in a variety of sizes. The one we are using is called a 10-meter MOCNESS because it samples an area of about 10 square meters. It has a rigid frame and six different nets with codends attached that can be opened and closed at different depths through the touch of a button on the MOC10 operator’s computer. We know the exact depth of the net due to the conducting cable that attaches the MOC10 frame to the ship. This allows information to be sent back to the ship from the many sensors mounted to the frame. In addition to depth, the MOC10 sensors include temperature and conductivity (salinity). The multiple codends allow us to sample within particular depth zones so that we can learn where the organisms live. For example, whalefishes, like the one pictured here, live only below 1000 meters and the lanternfish is only found above 1000 meters.
The nets only fish one at a time and are attached to the frame in such a way that as one net closes it opens the next net. The MOC10 is sent down to its max depth of 1500 meters with the first net open which is called an oblique trawl since it samples from the surface to depth. At 1500 meters, a signal is sent through the conducting cable to tell the MOC10 frame to open the next net, which closes the first one. Our sampling plan is to target the following depth layers: 1500-1200 m, 1200-1000 m, 1000-600 m, 600-200 m, and 200 m-surface. Keep an eye out for a later post on the layers of the ocean to find out why!
Tagged in: Deepend News