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We have lots of great posts planned about tiny sea monsters, what its like to live and work at sea on a research ship, and introductions to the crew of the R/V Atlantic Explorer (the guys who make the whole thing happen). So keep visiting and keep the great questions comming!!!
Steve Tuorto
What has been the weirdest copepod you’ve seen?
Justin, what kind of skills do you need to create your own instruments ?
Before you design any instrument, you should first decide what problem you are trying to solve. This may be something scientific, but can also be something just for fun. The design process generally starts with a pencil and paper design and is followed by computer simulations or models. Once you obtain the necessary hardware (e.g. optics, mounts, microcontrollers, sensors, and so on), it is time to get to work in the lab. This is often the most fun part, and usually involves revising your initial ideas. At some point, you will be ready to move your design outside of the lab, and this may involve designing the housing for your instrument. What happens after this depends on the purpose of your instrument, but often includes calibration and testing, and perhaps field deployments. It is often the case that you’ll work with other engineers throughout this process, especially for more complex instruments. In fact, the best way to get started building instruments is to work on a smaller part of a larger project. The necessary technical (hardware and software) skills may vary depending on the project, but most important is being interested in solving problems!
-Justin
Jonathan Cohen – What made you take an interest in studying how marine organisms see?
Ha! Good question. My father is an optometrist, which probably had something to do with my interest in eyes. But my interest in marine animal vision began on a short research cruise in 1998 near Bermuda. We collected plankton during the day, observed and experimented with them on the ship, then repeated this at night. Doing this, I got to see diel vertical migration first hand. Diel vertical migration is the vertical movement of zooplankton and fish from deep waters during the day into shallower waters at night. This happens at sunset, and by sunrise the animals descend again to their daytime depths. This behavior allows the animals to avoid predators in deep dark water during the day, and then to feed “under the cover of darkness” in surface waters at night. After seeing this on that cruise, and the amazing marine zooplankton that do it, I was hooked and have been studying zooplankton behavior and physiology ever since! Jon Cohen
Mr. Cohen, out of all the species in the ocean why did you choose to study the eyes of a copepods? Also are there other methods to test the sensitivity of an organisms eyes? If so what are they?
you guys are doing pretty well out there, i have to know why did you decide to go on this trip?
Jonathan, what equipment do you use to see how marine organisms view through their eyes?
Professor Cohen: Do fish in general see color or in 3 dimension?
Some fish do see in color, particularly in shallow and clear waters. In the deep-sea, where the wavelengths are limited to the blues, few fish seem to have that ability.
-from Jonathan Cohen
Justin Haag:
What type of instruments did you develop in order to understand how the animals use light to avoid predators.
Hi Lauren,
Please see part of my response to a previous post:
For my work, I’ve chosen to focus on predation aversion, and two particular aspects of this: physical appearance and the ambient light field. I previously built an instrument to measure how light is scattered from the skin of a few deep sea species of mirrored squid and fish. These measurements provide us with a quantitative understanding of the appearance of some of the animals that live in these parts of the ocean. More recently, I built two highly-sensitive radiometers that measure a quantity called `downwelling irradiance’ which can be thought of as the light that is falling downward (from the surface) in the ocean. These are the instruments that I brought with me on the CST cruise. I am interested to see what the downwelling irradiance looks like at up to 500 meters deep in the ocean, as we have many models, but few measurements at these depths. I hope that with the combination of information from animal appearance and an improved idea of what the deep sea habitats look like, we can discover some of nature’s strategies for deep sea biological camouflage.
Thanks for the question!
-Justin
Jonathon Cohen:
How are you going to study the eye of this animal and then further understand how deep it sees light?
Jonathan Cohen:
How will testing the sensitivity of the copepods eyes allow you to know how they will use their vision and light to find food, avoid predators, and find mates? Do you think the copepods above or below 200-500 meters would have different results?
Karen Stanieszkin:
What will you do with the zooplankton size-diversity index once you have completed it?
Hello- thank you for your question! I will use the size-diversity indexes from each station on this cruise to do a few things:
1) I will compare the size diversity at each station to environmental parameters, like day vs. night, nutrient availability, amount of chlorophyll available as food for zooplankton, etc. From this, I hope to get an idea of what conditions support larger-bodied or smaller-bodied zooplankton.
2) I would like to compare the diversity indexes from this area to a contrasting area, such as the Gulf of Maine, or maybe the Arctic or Antarctic Oceans. From that comparison, I hope to contribute to a growing understanding of global plankton size diversity, and the mechanisms driving those big patterns.
Zooplankton body size is important because it is related to food web dynamics and even carbon flux. Larger plankton can support larger and more upper trophic (food web) levels, such as fish. Larger zooplankton also have larger fecal pellets. When a zooplankter eats lots of smaller plankton, and repackages them into larger fecal pellets, those pellets are more likely to sink to the seafloor. If they sink deep enough, they can be sequestered from the ocean-atmosphere system for a long time. In this way, zooplankton size is important to the global carbon cycle. Understanding the ocean conditions that support different sizes of zooplankton can therefore help us understand variability in ocean food webs and carbon cycling!
~Karen S.
Mr. Cohen, what does the equipment you use to study the copepod’s eyes look like and how does it work?
Several of you have sent in great questions on how I do my experiments, and how the data can be used to understand visual ecology, so I will answer them together here.
There are several options for measuring how zooplankton can see. One common way is to use the animal’s swimming behavior toward or away from a light to determine what color(s) they see and how much light it takes to generate a behavioral response. This has been done on research ships, but is difficult because these animals live in the open water and are not used to contacting hard surfaces like the walls of the experimental chambers used for behavioral experiments. Once in a test chamber, they may just spin in circles, or they may just lie on the bottom disoriented. So, on this cruise I am using a technique called “electroretinogram recording” to study eye function in copepods and other zooplankton. The basic idea is that the cells in the eye which absorb light and are used for vision (called “photoreceptors”) change the electric field around the eye when these cells capture light. By using a very small “electrode” which is just a tiny metal wire, and an amplifier, I can measure these small changes in the electric field around the eye. It is important that the animal is kept at the temperature of its habitat during the experiments, and is kept in the dark unless it is being given the quick (100 millisecond) light flashes during which I measure the electric field around the eye. It is also important to eliminate all stray electrical activity around the animal – this is easier said than done because there are wires carrying electricity everywhere on a ship! To keep all these things under control, I have the animal inside a metal box called a Faraday Cage, and in a temperature-controlled water bath. The copepod or other zooplankter is super glued to the head of a pin to keep it from swimming away during the experiment (not an easy thing to do on a rocking ship!). All of this stuff can be packed in a few big boxes and brought anywhere around the world to do these experiments on land or at sea!
The experiments I am doing on the ship have focused on visual sensitivity, or how much light is needed for the copepod Pleuromamma to see. I have also done some experiments with krill that were also caught in the plankton nets. When I return home from this research cruise, I’ll take the visual sensitivity data and create a mathematical model (basically a set of equations that let me calculate how much light reaches each depth in the ocean) and hopefully the measurements made by Justin Haag on this cruise, and figure out how deep in the ocean these copepods can see. Pleuromamma are strong diel vertical migrators (see my earlier response to questions for an explanation) and I would like to find out if and how they are using their eyes in this predator avoidance behavior. I expect that their eyes will be more sensitive to light than the eyes of shallower species. It may also be that Pleuromamma are using vision to detect bioluminescence for avoiding predators, and for finding food or mates. With the visual sensitivity data and some measurements on the shape and size of the copepod’s eye, I can model the copepod’s ability to see a luminescent flash at different times of day, from different distances, and so on. This sort of process is pretty typical of sea-going science – the work we do on a research ship is just the tip of the iceberg, many other analyses are done once we return home.
-from Jonathan Cohen
Jonathan Cohen
what new information have you found about deep-see animal’s bioluminesence?
On this cruise, I have not been focusing on bioluminescence. But, the main copepod I am working on, Pleuromamma, is luminescent, so it will be interesting to see if its visual system may relate to its light production. On a recent scientific expedition in the Arctic I was studying vision and bioluminescence in the “polar night” along with colleagues from Norway and the US. Our findings from the far north suggest that luminescence of deep-sea organisms is important in shallower waters during the polar winter.
-from Jonathan Cohen
To Justin Haag-
What kind are you served on the ship?????
The Food
Gerardo,
I think you’ll be happy to see the new ‘Meet the Chefs’ post. We eat what they cook!
-Justin
Jonathon Cohen:
What percent of the ocean is unexplored?
This question is for Steve Techtmann how much oil and pollutants can each Organism absorb/ How will you figure this out ?
Thanks ,
Max
@Steve Techtmann
Will you be looking into developing a group of different and most efficient oil-eating bacteria that scientist will effectively be able to use in a certain area for the future? Please explain, thank you and greetings from San Diego High (MVPA)
Hi Aisha and Elvis,
That’s a great question. What we have found so far is that similar oil-eating bacteria are present in many of the oceans where we have looked. We are hoping to find ways of stimulating the native oil-eating bacteria in an environment rather than adding bacteria that are not native. While it’s appealing to get the best oil-eating bacteria from around the world and use them to clean up oil spills, we’ve found that if we try to add a non-native bacteria into an environment they often can’t compete and will die off. So it’s better to use the native oil-eating bacteria, that most likely live in most environments to clean up the oil and find ways of helping them do it better. So what I’m trying to do is find out oil-eating bacteria live in these waters and how well they eat oil as well as what can help them do it better. By studying oil-eating bacteria in the lab we can find out what is required for them to function effectively and use that information to stimulate the native bacteria in an environment in the event of an oil spill.
Thanks,
Steve Techtmann
Hi dad,
Do you get any free time or do
You just work all day and all night
Hi Payton!!
Most of my spare time I have spent working on the blog or have meetings, but I do get some free time. Not much, I am very busy day and night. But I got to watch a movie, do some reading, and hang out with people and talk. The people I am on the ship with are very nice and very interesting so I like to talk with them.
Cant wait to see you, miss you very very much!
Love,
Dad
Ps. Tell Sydney and mommy that I said Hi and I miss and love them!!
What day are you coming back
Hi Syd!
We are pulling up to Bermuda right now! We have a few days of unloading the ships and meetings, and then I will be flying back to NJ. I will be home late on Thursday. You guys might have to come pick me up from the train station.
See you soon!
Love, Dad.
Justin Haag:
how exactly did you go about studying different animals camouflage strategies. what did you look for to determine how effective a certain deep sea animals style of camouflage is at protecting them from predators
Christopher Hayes:
do aerosols have any negative impacts on the ocean environment. if so how could we limit these harmful effects on the ocean
Hello,
I was wondering if you enjoy the lifestyle of going on research trips and working on a boat. I know it is work, but is there time to stop and enjoy it?
-Max
Hello Max,
This was my first cruise, but I loved the lifestyle. It is tons of constant work, and you are always exhausted, but it is terrific to constantly be at sea. And we do get time here and there to read, or just enjoy the ocean. So even though it is a lot of work, it is totally worth it.
Thanks,
Steve Tuorto
This is a question for Katherine Allen
What role does the ocean play in climate change?
Karen Stanieskin
Why do you study Plankton poop?
Steve Tuorto
how does bacteria grow?
Hello Hannah,
Bacteria grow the same way we do. We eat the nutrients we need to get energy, grow and keep our bodies healthy. Some bacteria do this in strange ways, but most of the bacteria on earth do this the same way we do… they eat a carbon source that has the nutrients they need, and their cells break it down into all of the parts they need.
Thanks for the question,
Steve Tuorto
why do study small animals instead of big animals
Hi Hannah, Many people do study larger animals, just no one on this cruise. But many of the smaller animals have a much bigger impact on the ecosystem. For instance, if you add up all the copepods in the ocean, they will weigh more than any other animals on earth.. even all the elephants or whales all added together do not weigh more than all of the copepods.
Thanks,
Dr Steve
Sam Monk- what have you found so far?