- Deep Sea Fauna
- Environmental Variability
- Consequences of DWHOS
- Student Research
- DEEPEND Publications
Recent blog posts
Hello! My name is Ryan Bos and I am a Masters Candidate in Marine Science at Nova Southeastern University. Currently, I am doing an appraisal of microplastic ingestion in deep-pelagic fishes and crustaceans in the Gulf of Mexico (GoM) with Dr. Tamara Frank and Dr. Tracey Sutton.
Each day, nearly every person on Earth uses plastic items. It is all around us. It is in our clothes, cosmetics, vehicles, and if you carry a smartphone around with you, odds are that it has a plastic component. As humans, we manufacture and use plastic at alarming rates, and take it for granted. Plastic production is projected to increase with increases in the human population, yet plastic pollution is already infesting our oceans and will continue to persist for hundreds to thousands of years because of plastic’s inherent resiliency. I want to put the plastic crisis we are facing into perspective. There are ~34,000 extant species of fishes, with the most abundant genus of fish, Cyclothone, consisting of 13 species. These 13 species comprise an estimated 1,000,000,000,000,000 individuals. By the year 2050, the number of fishes in our oceans will be equal to the number of plastics. What is alarming about this statistic other than the number of fishes and plastic particles being equal? There are 33,987 more species that contribute to the total number of individual fishes in our oceans, and most of these plastic particles cannot be seen with the naked eye!
Deep-sea micronekton are integral parts of pelagic ecosystems, as they serve as key intermediates in oceanic food webs, contribute significantly to overall abundance and biomass, make substantial contributions to carbon flux, and serve as links between shallow and deep-pelagic waters. Thus, they are exemplary targets for microplastic studies.
Microplastics, as the name implies are small pieces of plastic that range in size from 1 µm - 5 mm that are categorized as being a fragment, film, spherule, foam, or fiber. Once ingested, an animal may experience pseudosatiation (the feeling that they are full but have not received any nutrition), obstruction of feeding appendages, decreased reproductive fitness, and death. Pictures of these categories are portrayed below, excluding foams, of which none were found. To determine if a particle is a piece of plastic, we used the ‘hot-needle,’ or ‘burn-test.’ It is a rapid and cost-effective technique for plastic determination. When plastic is probed with a hot-needle it either leaves a burn mark, melts, or in the case of fibers, curls up and is repelled by the needle.
Regrettably, there are no previous estimates of microplastic ingestion by deep-sea fishes and crustaceans in the GoM, despite the commercial importance of this ecosystem. A total of 723 individuals (316 fishes and 407 crustaceans) from a combined 48 species and 11 families were dissected and visually inspected for microplastics. Plastic items were found in both fishes and crustaceans. A total of 263 microplastics were identified, with crustaceans and fishes consuming 146 and 117 microplastics, respectively. Total micronektonic crustacean and fish plastic ingestion was approximately 31 % (n = 190/618) while 16 % of euphausiids (n = 96) and 11 % of crabs (n = 9) contained at least one piece of plastic.
Interestingly, there were apparent differences in type and number of microplastics ingested by fishes and crustaceans, with crustaceans ingesting predominantly fibers, as opposed to fishes, which consumed a substantial number of fragments. Further, vertically migrating taxa of fishes contained more microplastics than non-migratory taxa, but the opposite trend was observed in crustaceans. In fact, non-migratory crustaceans consumed significantly more plastic than all other taxa. Curiously, the non-migratory crustacean taxon with the highest frequency of plastic ingestion, the Benthesicymidae, are all habitual consumers of marine snow. That, coupled with the smaller size classes of microplastics found in this study, may be indicative of marine snow’s importance in biogeochemical cycling of microplastics.
As commercial fishing efforts scale up to harvest the deeper layers of the ocean, these results will be important for assessing risk associated with consumption or indirect consumption by the deep-sea biota. Importantly, larger deep-pelagic crustaceans appeared to have more plastic in them than small conspecifics, but size was not indicative of plastic ingestion by fishes, and no significance was observed for either group of animals.
Empirical cumulative distribution functions of carapace length of crustaceans (A) and standard length of fishes (B) that did and did not ingest microplastics. Two separate (one for crustaceans, one for fishes) Kolmogorov-Smirnov tests generated p-values of 0.09 and 0.924, respectively.
Deep-sea food webs are largely understudied relative to coastal studies, but results to date suggest a great deal of complexity. Our data reveal that more scrutiny should be given to deep-sea ecosystems with regards to plastic ingestion. These food webs are understudied because of the enormous expense and difficulty of obtaining deep-sea samples, highlighting the importance of projects such as DEEPEND.
A brilliant new way to aid in the fight against plastic by doing laundry: https://coraball.com/
A resource for learning more about plastic: https://marinedebris.noaa.gov/info/plastic.html
An article about how plastic is killing our oceans, by Wendy Lipscomb from the website 'It's a fish thing': https://www.itsafishthing.com/plastic-in-the-ocean/
Hi folks, welcome back to the blog! This edition of Master’s Monday will be brought to you by Mike Novotny. I am a Master’s candidate at Nova Southeastern University, working under Dr. Tracey Sutton in the Oceanic Ecology Lab, where I study the bathypelagic zone and the fishes that call this environment home.
The ocean is commonly divided into three layers based on sunlight penetration with depth. The midnight (aphotic/bathypelagic) zone is the deepest layer, which starts around 1000 meters. The bathypelagic zone receives no sunlight, has consistent near-freezing temperatures, contains pressures exceeding 100 times that found at the surface, and is the planet’s largest ecosystem! It is within the depths of the bathypelagic zone that you will find the very intriguing group of fishes that belong to the family Platytroctidae, known also as Tubeshoulders. Due to the rarity of specimens, there is very little information known about these fishes, which is where my research takes off!
Tubeshoulders get their name due to a unique tube-like structure that can be found in the shoulder region of all fishes in this family. This tube leads to an organ that contains a luminous blue/green fluid, which allows the luminescent material to be expelled, possibly, for a potential defense mechanism by temporarily distracting the would-be predator. Below is a great video about bioluminescence, but jump to 10:40 to see how platytroctids get their name!
Tubeshoulders have very large eyes, especially for a deep-sea fish! These large eyes are excellent at detecting low-level, point source light and distance ranging, suggesting they may be visual predators, however, the diet of tubeshoulders has yet to be examined. My thesis research addresses this crucial data gap by exploring the feeding behavior and documenting prey preferences of this bathypelagic fish family. Based on stomach content analysis these fishes seem to feed infrequently. I visually examined and identified the gut contents under a compound microscope, which revealed that members of this family tend to be generalist zooplanktivores, consuming a wide variety of taxa such as, copepods, ostracods, chaetognaths, gelatinous taxa, and even the occasional squid! This study represents the first investigation into the diet of this fish family, and adds to the sparse community data of the bathypelagic zone, by identifying nutrient pathways that connect this deep-sea ecosystem to the upper ocean.
Hello! My name is Richard Hartland, I am currently working on a Master’s degree in marine environmental science at Nova Southeastern University. I am a part of Dr. Tammy Frank’s Deep-Sea Biology laboratory. My thesis is focused on performing a taxonomic and distributional appraisal of the deep-pelagic shrimp genera Sergia and Sergestes of the northern Gulf of Mexico, in the area where the Deepwater Horizon oil spill occurred in 2010. The shrimp I study are important members of the oceanic community, both as consumers of zooplankton and as prey for higher trophic levels (e.g., tunas, mackerel, oceanic dolphins).
Left: Sergestes corniculum. Right: Sergia splendens. Images courtesy of T. Frank.
I will be examining the abundance (how many) and biomass (how much they weigh) of the shrimps in the Gulf, and whether or not these values have changed over the years, starting in 2011 (six months after the oil spill) and continuing from 2015, through 2016, and into 2017. The boxplot below shows changes in the patterns of abundance for the most abundant species, Sergia splendens. These data seem to show a sharp decrease in abundance between 2011 and 2015, while slowly increasing in the years to follow.
Boxplot of Sergia splendens abundance from 2011 through 2017.
What we are seeing is a reduction in the number of individuals caught from 2011 and 2015, then we see an apparent increase from 2015 to 2016 and into 2017. Although there appears to be a dramatic drop in the abundance from 2011 to 2015, we cannot state that this is due only to the oil spill in 2010, as there are many other reasons the numbers could be different. What we should do is continue to sample in the same areas and monitor how the population changes over time. I am also looking into how these shrimp move up and down the water column during daylight and nighttime hours. This daily vertical migration is one of the many ways that deep-sea organisms are important components of oceanic ecosystems – this movement takes carbon from the near surface (in the form of their food) and transports it deep into the ocean, thus helping mitigate the increases in atmospheric carbon due to the burning of fossil fuels.
Hello Everyone! My name is Devan Nichols, and I am a master’s student at Nova Southeastern University working in Dr. Tamara Frank’s deep-sea biology laboratory. Our lab specializes in deep-sea crustaceans (aka shrimp!) and my thesis focuses on a particular family of deep sea shrimp known as Oplophoridae. As we all know, shrimp are fairly small organisms in the grand scheme of creatures that live in the deep sea, so why is it important that we study them? Great question! The deep-sea shrimp that I study range in size from 2-20 cm in length. Organisms this small, are perfect prey for larger animals such as deep-sea fish, squid and marine mammals. This means that Oplophoridae make up the base of the food chain, and act as primary producers for many organisms that are higher in the food chain. When the base of the food chain is impacted, even in a small way, it can throw off the balance of an entire ecosystem. These little guys are important!
Two species of Oplophoridae; Systellaspis debils (left) and Notostomus gibbosus (right). Images courtesy of DEEPEND/Dante Fenolio 2016.
Very little is known about the effects of oil spills on the deep sea. When people think of oil spills what usually comes to mind are the impacts it has on the ocean surface. When these disasters occur, the deep sea is not often thought of. It is kind of an out of sight out of mind situation. The Deepwater Horizon oil Spill (DWHOS) occurred in the Gulf of Mexico on April 20th 2010 releasing an estimated 1,000 barrels of oil per day for a total of 87 days into the Gulf. This oil was released from a wellhead located approximately 1,500 m deep.
My thesis is unique in that I have the opportunity to examine data collected one year after the oil spill (2011) and compare it to data collected five, (2015) six (2016) and seven (2017) years after the Deepwater Horizon oil spill. I am looking particularly at oplophorid assemblages. This means that I am looking at how the numbers of shrimp may have changed (abundance) and how the weight of shrimp may have changed (biomass) over these sampling years. The boxplot shown below, shows the patterns that I am seeing so far in oplophorid abundance as time goes by. These data seem to show a sharp decrease in abundance in 2011 to subsequent years.
Boxplot of oplophorid abundances during the four sampling years.
Although we cannot attribute any of these changes to the oil spill directly because we do not have a baseline (data from the area collected before the spill), we can still monitor how this oplophorid assemblage has changed over time, and use this information as a baseline to monitor future changes in the Gulf of Mexico. Along with assemblage changes, my thesis will also provide information on whether or not certain species are seasonal reproducers, and if the presence of the Loop Current has any significant effect on oplophorid ecology. The deep sea is a mysterious place, and scientists still have a lot to learn about its complexity and the organisms found there. The picture below shows the net we use to catch these deep sea shrimp, and some of the equipment we use to lower the net into the deep sea!
A 10-m2 MOCNESS net being towed behind the RV Point Sur during a DEEPEND cruise.
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.
Hey, have you ever heard of a heteropod? You may have heard that term associated with terrestrial spiders, but what I am talking about is a group of very special marine snails! Hi, I’m Kris Clark, a graduate student from the University of South Florida College of Marine Science, studying marine gastropod molluscs collected from the DEEPEND cruises. My little creatures are within the Superfamily, Pterotracheoidea. These floating sea snails, commonly called heteropods or sea elephants (albeit they are generally small), are found throughout the world’s oceans in tropical and subtropical waters where they have adapted to pelagic (open sea) living. I like the name sea elephant as it describes their resemblance to an elephant’s trunk. These animals have an extended proboscis or nose-like feature that terminates with their mouth. The term heteropod was coined for these little beasts back in the 1800’s when they were first realized. The term was used because of the evolutionary development of their swimming fin from their ancestral foot – hetero meaning “different” or “other”.
There are three family groups that are categorized by the type (or lack) of a shell. Atlantidae have a full shell where the animal can fully retract inside. Carinariidae have only a very tiny partial shell that covers their visceral mass and gills. And lastly, the Pterotracheidae lack a shell entirely. All heteropods have mostly transparent bodies, have an evolved foot that now serves as a swimming fin, have a mobile proboscis for feeding, and have spherically gelatinous eyes for locating prey. They feed on copepods, polychaetes, brine shrimp, salps, tiny crustacea, jellyfish, pteropods, and other heteropods.
Most people have not ever heard of heteropods. And that’s not surprising. This group of sea-life is still understudied, however more investigations are developing, including mine. One important and interesting finding about heteropods is that there are a lot of them in the oceans. And since they are found in every ocean and are very abundant it is estimated that these swimming snails are highly important to the ocean foodweb – mainly fishes rely on the heteropods to eat, and larger prey eat these fishes, and so on. So heteropods post an important position in the food hierarchy in the ocean system. Many other compelling attributes have been discovered about little heteropods… keep in touch with our future articles for more curious discoveries!
Want to learn more now? Check out these fun videos of swimming Pterotracheoidea…
Left to right: back: Jessica, Alex, Michelle, Cori, Travis, Jillian, and Nina; front: Jason and Rich
HAPPY 4th of JULY!
Scientists still get to celebrate while we’re out at sea! Check out our tattoos! :)
Today is our last day of sampling. We started bright and early again at 6am. It rained a bit, but it was accompanied by a full rainbow arching over the boat. Nice way to start off the morning!
You guys are probably wondering how we collect all of the larval fish I showed you on the last blog post. Well, we deploy a bongo net off the back of the boat and a neuston net off the side. Both nets are brought on board and the samples are washed down into the codends. The contents of the codends are rinsed/poured and put into our sample jars. The samples are brought into the wet lab for a closer look and a potential photo. Some of the larger specimens (e.g., tunas, swordfish) are frozen for genetic analyses.
I set up a GoPro around the boat to show you guys how we sample at each station. Let’s take a look of some of our scientists at work:
Bongo nets and the sunset last night. Neuston net.
Rich is collecting water for the YSI and for the food web study. Nina is reading the water's temperature, salinity, and dissolved oxygen.
Rich, Nina, Jillian, and Jason are retrieving the bongo nets. Everyone's rinsing down the nets, while Michelle is recording the
Jillian is pouring her plankton sample out of the codend. Jason and Nina are rinsing the bongo nets.
Nina and Jessica are putting the sample into the jar. Jessica is looking at a larval tuna under the microscope/taking a picture.
Alex and Cori just retrieved the neuston net. Jillian, Alex, Cori, and Travis are sorting the neuston net sample.
Jason and Travis sorting through Sargassum. Jason and Alex looking at our catch!
Dr. Michelle Sluis is the PI on the cruise. She is recording the data for each tow (e.g., start time, location, etc.) in the pictures above.
Hope you enjoyed the pictures!
Last night we cruised towards our southern transect. We arrived at our first station and began sampling at sunrise (6am). We've hit 10 stations so far today! We collected many of our targeted species and more!
On the boat, we use a camera attached to our microscope to help us take pictures of the tiny fish. Here's some of our catch:
Alex found a siphonophore.
Cori, Travis and Jillian on deck and ready for the next tow!
All smiles here!
My name is Nina Pruzinsky. I’m out in the northern Gulf of Mexico with Texas A&M sampling for fish larvae on the R/V Pelican. We’ll be out here from July 1-5th. The scientists onboard include: Dr. Michelle Sluis (TAMUG), Jessica Lee (TAMUG), Travis Richards (TAMUG), Cori Meinert (TAMUG), Jillian Gilmartin (TAMUG), Alex Southernland (TAMUG), Jason Mostowy (TAMUG), Richard Jones (FAU) and Nina Pruzinsky (NSU).
We left the port at LUMCON at midnight on June 30th and traveled to the first station (Station 48) during the night. We started our sampling around 10am yesterday. We finished nine stations during the day and did two night tows. During the day we are using a neuston net and bongo nets to sample for larval fish. The neuston net tows for 10 minutes at the surface and the bongo nets sample to about 100 m depth. At night, we only tow the neuston net. This way, we can compare the differences between day and night tows at the same station. Additionally, Alex is sampling for gelatinous zooplankton (jellyfish) for genetic analyses, Jillian is Gtowing another plankton net to look at the community structure of zooplankton, and Travis is collecting water samples in order to characterize the food web in the Gulf.
Yesterday we caught tunas, billfish, dolphinfish, flyingfish, eel larvae, remora, frogfish, triggerfish, pufferfish, rough scad, lanternfish (at night) and more! Check out the pictures below! As you can see, all of our fish are extremely small!
Today we started sampling at sunrise around 6am and have completed three stations. We already caught some tuna and dolphinfish larvae!
Stay tuned for more pictures and updates on the cruise!
R/V Pelican before depature.
Larval dolphinfish (mahi-mahi).
Michelle and Cori preparing the neuston net.
Jillian setting up the plankton net along with the bongo nets.
We also were able to dip net a juvenile tuna last night for my thesis!
Another day at sea – one of our last for this cruise.
My name is Laura Timm and I am a PhD student at Florida International University. This is my fourth DEEPEND cruise and the data we collect from it will contribute to the last chapter of my dissertation.
I work on crustacean genetics. Specifically, I use the DNA of a few shrimp species to describe diversity and characterize how (or if) it is moving within the Gulf. These two things, diversity and gene flow, provide a lot of insight into the health and resilience of these target species. Most of my work with DEEPEND has focused on three shrimp: Acanthephyra purpurea is a bright red color and produces a bioluminescent spew to scare off predators.
Systellaspis debilis is also red (though younger ones can look orange), but with tiny light-producing organs called photophores polka-dotting its body.
Sergia robusta can be dark red or even purple and has photophores around its mouth and tail.
To me, all three are uniquely beautiful.
My research focuses on questions related to genetic diversity, which is a good metric for species health. Where is the most diversity found? Has this changed since 2011? How is diversity distributed? Is some genetic diversity unique to certain places? Answers to these questions provide unprecedented insight into how the Gulf copes with disturbances.
Now, a little perspective.
We trawl with a MOC10 net. It is very large. Every person on the ship could go stand in the frame of the net. However, when compared to the size of the ocean, it is tiny – it has been described as the equivalent of investigating terrestrial diversity using just a butterfly net. Yet, we still catch thousands of shrimp. Of these thousands of shrimp, a few hundred are targeted (A. purpurea, S. debilis, S. robusta). Of these hundreds, 96 are sequenced (this is due to the sequencing process; I can only sequence 96 at a time). The genomes of these species have not been sequenced, so I target a few thousand base pairs of DNA. A few thousand base pairs out of billions of base pairs. About 100 shrimp out of hundreds, hundreds out of thousands, thousands out of every shrimp in the Gulf. This tiny amount of data (which, in the history of science, is unprecedentedly large) can tell us so much about the animals living in the Gulf and how they came to be there and whether they are likely to survive whatever comes next.
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.
For centuries, sailors and scientists have observed birds landing on ships. A ship out at sea is like a moving island in the ocean. Various birds may seek refuge on ships, especially when storms occur, or are attracted to the lights of the ship at night. It makes sense that many of these birds are sea birds, but a number of land birds may make migrations across ocean areas or get blown out to sea by storms along the coast. Given the several storms during our cruise, it is no surprise we have had a number of birds land on or fly close to our ship, while it was 100-150 miles off the coast of Louisiana, Mississippi, and Alabama. So, here is a short rundown of the birds we have seen recently…
Purple Gallinule – spent a couple days resting on one of the deck cranes until it took off.
Louisiana Waterthrush – this wood warbler took refuge in a corner of the deck for a while before flying away.
Northern Oriole – just showed up on the ship superstructure, rested for an hour, and took off.
Cattle Egrets – we have had several stay around the ship, with a flock of 14 circling the ship one morning.
Bobolink – a few individuals flew around the boat this morning and one perched on the anchor chains and other structures on the bow.
Barn Swallows – One morning just before another squall, there was a flock of approximately 100 circling the ship from 5-6 AM. A flock of about 8 flew by the ship yesterday after several days of clear weather. This morning 3 were perched on some fixtures.
We also had a very large flock of a small birds that might have been American Goldfinches, but it was too dark at 4-5 AM to see them clearly.
Coastal birds we have also seen far out at sea include…
Osprey – one landed on a container on the forward deck, sat for a few minutes, and then left when it was disturbed by a crew member.
Brown Pelicans – three juveniles paddled along with the ship and flew short stretches to catch up again.
Caspian Tern and Royal Terns – one Caspian and two Royals sought a perch on a part of the stern of the ship during a rain storm.
Laughing Gulls – 3 juveniles and 1 adult stayed around the boat for a day during and immediately after a storm.
Studying the animals in the deep sea within their natural habitat is very difficult. It often requires sophisticated instruments or equipment and scientists have to be careful to make sure that they don’t disturb the animals they are studying. During the DEEPEND cruises, we use sound to study how animals move through the ocean and the daily movement patterns as they go up and down from the surface at night to the deep sea during the day. Using sonars, we can create a picture of where the animals are by measuring how much sound they reflect. While this gives scientists a broad picture of where the animals are, it does not provide enough detail to look at the individuals within the layers.
During this cruise, we have been using a new tool to study fish and invertebrates down in the depths of the ocean. We have attached an autonomous sonar (WBAT- WideBand Autonomous Transceiver) on to the MOCNESS (see photo above) to look at the animals that are near the net. This new sonar provides much higher resolution data at small scales, kind of like an underwater magnifying glass. With this new instrument we can look at the individuals that are being collected by the MOCNESS and then compare this back to what we see on the ship’s sonar. So far we have noticed that the animals do not seem to avoid the net as we expected they would.
This is my first research cruise in over ten years, and I am quite excited by the great opportunity. I once went out to sea fairly routinely when I worked at Harbor Branch Oceanographic Institution (HBOI), but the goals were much different then. This time for DEEPEND, we focus on the pelagic mid water column organisms in the Gulf of Mexico, which remains a fairly new habitat for me to explore.
My role for DEEPEND on this DP05 cruise is to ensure proper collection of new bacterioplankton samples from Gulf of Mexico seawater at various depths. I am basically following the same procedures as past cruises for consistency.
The main instrument for collecting water is the CTD (conductivity, temperature, and depth) which is loaded with a rosette (circular arrangement) of twelve Niskin bottles that can each hold 12 L. These traditional aquatic water collectors close at precise depths which I can control from the ship. R/V Point Sur crew member, Marshall Karmanec, helped get me accustomed to running and deploying the CTD on this cruise. With the controls, I can designate where and when bottles are opened at specific depths. Once the bottles are filled and back on deck, I am able to drain 4-5 L of seawater and bring them into the lab. I share a filtering station corner of the ship’s lab with FWC/USF technician Tess Rivenbark. While most of the other DEEPEND scientists are identifying charismatic deepwater megafauna, I filter marine microbiomes onto special sterile 0.45 micron filters. “Sterile” is the operative word here, since the lab is not the optimal place for traditional “microbiology” methods. Essentially I am preserving the communities on the filter by careful handling, freezing and recording, so they can all be brought back intact to my molecular lab at the NSU Oceanographic Center for DNA extractions and sequencing that will eventually illuminate the distribution and dynamics bacterioplankton in much greater detail.
The CTD also measures where the very important oxygen minimum and chlorophyll maximum zones occur vertically within the water column. These zones represent important parameters for oceanographic work since they can delimit where food chains begin or end, where maximum photosynthesis (the production of oxygen from cyanobacteria) happens, and we also have found distinct microbial communities (also known as “microbiomes”) associated with each zone. With DEEPEND postdoctoral scientist Cole Easson, we have been characterizing these microbiomes from past cruises, and our current results point to significant depth stratification of microbiomes in DEEPEND Year 1 data, which among other interesting findings will be submitted in a forthcoming manuscript. This year 3 sampling adds to the temporal dimension of the project and is also very exciting.
On every cruise, it’s tradition to send decorated Styrofoam cups down on one of the instruments to shrink them. Styrofoam is mostly air, so when cups made of Styrofoam are sent to the depths, as the pressure increases with depth, the air inside the cups is compressed, and the cups shrink accordingly. Once they shrink, they stay that way, as Styrofoam isn’t particularly flexible – it doesn’t expand again when it comes to the surface. This year, we received a set of beautifully decorated cups from Theresa McCaffrey’s Advanced Art Classes at Tualatin High School. Ruth Musgraves, who developed and runs our Creep into the DEEPEND summer camps (http://whaletimes.org/?p=2186) has a daughter in one of these art classes, and they heard about the shrinking cups through her. They send out a box of cups, and the artwork is quite amazing, as you can see in the photos below. The best part is that they made some cups for us as well.
I’m really thrilled about that, because I’m pretty much still at the stick figure level when it comes to my artistic endeavors.
There is a pretty careful protocol that we must follow to package the cups, so that the cups shrink without collapsing inside of each other as they shrink at different rates. If two cups shrink together, one inside of the other, they’re almost impossible to get apart without breaking one. They must be loaded in mesh bags with open ends facing each other, with each row separated by tie wraps so they don’t float together and collapse together.
We can load 14 cups per bag, and two bags per CTD rosette. The CTD rosette is deployed to collect water samples at various depths, monitoring conductivity (C – as a measurement of salinity) and temperature (T) as a function of depth (D). We have to be careful that the bags do not interfere with any of the sensors or closing mechanisms on the bottles, so we never load more than two bags per deployment.