Past Questions of the Day:
February 10, 2007
Question 1: Can ultraviolet rays enter the seawater and cause mutations in the genetic material of the microorganisms that you are studying?
Answer: Ultraviolet rays can induce damage to genetic material in microbes, however, UV rays can only penetrate approximately a meter into seawater so most organisms don't encounter UV radiation. The shallowest depth that we sample from is 5 meters.
Question 2: We learned that there are huge swarms of krill further sounth in the ocean. Do they eat Prochlorococcus?
Answer: Prochlorococcus doesn't appear to survive in very cold waters. Their numbers diminish rapidly as water temperatures decrease and it seems like 20 degrees Celsius is their lower limit of survivbility. Krill are found in huge abundances where the water temperature is very cold (i.e.: the Southern Ocean). The temperature that is suitable for the krill is far too cold for Prochlorococcus to survive.
Above: The amount of cloud cover is sometimes a factor in what types of organisms we collect.
Question of the Day (February 08, 2007): Do atmosphere and surface weather at any given time impact the types of organisms that you capture from the ocean? (Otis Brown)
Answer: The answer to this question is both yes and no. Some organisms (i.e.: zooplankton and dinoflagellates) are able to move up and down in the water column and researchers onboard (Sue Brown and Karen Selph) have noticed differences in the microbial community depending on what time of day the samples are taken. Other organisms that are non-motile (can't move on their own), like Prochlorococcus, are found in the same part of the water column whether or not it is a cloudy day. We take note of the weather each day so that we can later correlate weather conditions with the results we have obtained for that station.
Question of the Day (February 06, 2007): Have you seen any large marine mammals since you left Hawaii? (M. Saxton, Knoxville, TN)
Answer: To our surprise, we have not seen any large marine mammals since we departed. No whales, dolphins, porpoises or seals. We thought for sure we'd have seen some whales because we passed through some of their breeding grounds, but so far we haven't.
Above: Filters are some of the most important things that we use to study microbes in the water. The outer part of this filter (white) does not have any organisms on it. The central, brown portion has organisms that have been filtered out of the water onto it.
Topic of the Day (February 05, 2007): You may have noticed that several pictures on this website are of filters or of people filtering water. Filters are an essential part of our research supplies. They are important for collecting the organisms we study from the water. They can also be used to exclude organisms of a certain size from our experiments. We work with many different types of filters onboard. The filters we use are made from a variety of materials including glass fibers, nylon and polycarbonate just to name a few. Filters can have different sized "holes" in them, we call the holes in a filter "pores". The pore sizes of filters that are used onboard vary from larger than one millimeter to 0.02 micrometers (that is .00000002 meters) depending on what we want to use the filter for. Large pore sizes are good at excluding organisms like copepods from experiments where we are trying to grow phytoplankton (copepods eat phytoplankton). Very small pore-size filters (0.02 micrometer) are used for filtering viruses out of the water so they can be enumerated (counted) using a microscope. Many filters are round in shape and are flat. If a filter is to be used to process lots of water it will sometimes be cylindrical in shape and have pleats in it to increase the surface area of the filter. The larger surface area ensures that the filter doesn't get clogged too rapidly.
Above: Ms. Graciela Breece's 3rd grade class from Nontaburi, Thailand at the Anubin Nontaburi School.
Ms. Breece's class has been following the progress of our trip very closely and they have submitted the questions we have answered below. We would like to ask any other classes or individuals that have been following our voyage to submit pictures as well. We'd love to see who has been traveling along with us. We'll put your picture up on the web too!
Questions of the Day (February 02, 2007): The folowing questions were submitted by third graders from Anubin Nontaburi School in Thailand. The students nicknames are given in parentheses and our answers are given in bold type.
1) How many kilometers have you traveled so far ? (Nut). As of this evening we have traveled 9,389 kilometers (that is 5,834 miles).
2) Do you want to do this trip again and do you like it? (Petch Girl and TungPang). Normally for this type of research you don't get to follow the same cruise track more than once. We are having a good time and would love to do it again, if possible.
3) How far down is the deepest part of the sea where you have sailed (PomPam)? The deepest part of the ocean we sailed over was deeper than 4,500 meters.
4) How fast do you go (Baiteay)? Optimally the ship cruises at 12 knots/ hr (13.8 mph or 22 kph). Currently because of our power problems we are traveling at 6 knots/ hr (11.1 kph).
5) Do you like to swim in the pool (Japan)? I have not gone in the pool, but some people do enjoy it after working all day.
Above: A dissecting microscope image of a barnacle that was foundin a net tow the other day. This barnacle was attached to a small piece of debris. There were many such pieces of debris that had these barnacles on them. The little tentacle-like projections coming out out the shell are what the barnacle use to catch food floating in the water.
Question of the Day (February 01, 2007): When you perform your diel experiments does each person stay up the whole time or do you work in shifts? ( Mrs. Prevenas's Seventh Grade Science Classes, Maui, Hawaii).
Answer: In general, all members of the science party are awake for the whole diel experiment. There is so much work that needs to be done that there is no time for sleep! In addition to the responsibilities of our own projects, we all pitch-in to help with the launching and recapturing of the CTD and any other deployments that are made. During the diel experiments we launch the CTD rosette every two hours, so by the time you finish processing your samples the CTD is already coming back onboard with more water to process!
The crew operates on a different schedule that the scientists onboard. Crew members work two four hour shifts each day. They generally work four hours and then have eight hours off. They do this everyday while at sea. The science technicians onboard work twelve hours straight each day and then have the next twelve hours off. The Captain of the Kilo Moana (and all ships) is on call 24 hours a day.
Topic of the day (January 27, 2007):
Left: Dissecting microscopic image of a colony of the cyanobacterium Trichodesmium. Right: Epifluorescent microscopic image of a Trichodesmium colony referred to in the text below.
January 29, 2007: Today we are going to highlight an organism that is being studied by several members of our science party. We have mentioned this organism previously, but now we'll discuss it in a little more depth. Thank you to Dr. Eric Webb for providing us with a micrograph and also a description of what we are looking at.
From Dr. Webb (see above picture): Marine cyanobacteria (prokaryotic photosynthesizing organisms) are important for providing the air that we breathe. Members of the genus Trichodesmium are also import for the global nitrogen cycle, since they are capable of converting atmospheric nitrogen gas into "fixed" nitrogen that other organisms can use for cellular materials. Since the open ocean is known for having extremely low nutrient concentrations (including "fixed" nitrogen), the importance of organisms like Trichodesmium cannot be overstated. On this cruise we are interested in determining the factors (or chemicals) that are limiting the growth and activity of Trichodesmium . Trichodesmium are special bacteria in that they can be seen by the naked eye and isolated from the water with a simple net tow. This is due to the fact that the cells frequently aggregate into floating structures called colonies.
The picture shows the results of a phosphate stress assay that we perform on the ship. Shown is an epifluorescent micrograph of a Trichodesmium field sample from the Western South Pacific assayed for phosphate stress, using an alkaline phosphatase (PhoA) detection technique (outlined in detail in Dyhrman et al Limnol. Oceanogr. 2002). Phosphate is thought to be important for limiting the growth of Trichodesmium in many oceanic regions. In the picture red/orange phycoerythrin autofluorescence (due to photosynthetic pigments) is visible in the filaments, while the green fluorescent product is due to PhoA activity. This particular colony of Trichodesmium had sufficient phosphate, but it would appear that it was supporting a large amount of other bacteria that were stressed for phosphate (the large green area).
Top: An image of water temperature and wind data taken from the Tropical Atmosphere Ocean Project (TAO) / TRITON buoys. The colors indicate sea surface temperature (SST). Warmer colors are indicative of warmer temperatures and the arrows indicate wind speed and direction (longer arrows are higher-speed winds). The data presented are 5 day averages. To learn more about the TAO/ TRITON project click on the following link www.pmel.noaa.gov/tao/index.shtml.
Question of the day (January 26, 2007):What is it about the water in the warm pool that causes it to get so warm? (Johanna R-K, Athens, GA).
Answer: The sea surface temperature (SST) in the Western Pacific Warm Pool annually climbs above 30 degrees Celsius. There are many factors that can influence seawater temperature, but the greatest factors influencing the temperatures found in the Warm Pool are the wind and the Sun. From the figure above you can see that the winds generally blow from east to west along the Equator. You can also see that the coolest water along the equator is at the eastern side of the Pacific (right side of figure). So basically, what happens is that the winds blowing from the east push water westward. This westward moving water is constantly being warmed by the Sun (Recall that the Sun is strongest at the Equator). Eventually the winds push the water all the way to the western side of the Pacific near Papua New Guinea (the gray island in the figure above) where all of this warm water continues to be heated by the Sun eventually resulting in temperatures higher than 30 degrees C.
Pictured: A view of coastal Noumea taken during our port call yesterday.
Question of the day (January 25, 2007): Does Prochlorococcus sp. have a way of reproducing that allows for genetic reshuffling? (Kalama Intermediate School).
Answer: Prochlorococcus, like other prokaryotes, reproduces asexually via binary fission. However, through a process known as horizontal gene transfer, genetic reshuffling can occur. This happens independent of reproduction, and occurs when foreign DNA gets into the cell and splices its way into the chromosome. Just how this is done, and how often this occurs, is a subject of great current interest to microbiologists.
Top: Shawn, Jan and Donnie are the three stewards on the ship. Bottom: A picture of the cabin bunks. The cabins are small, but sufficient.
Question of the day (January 23, 2007): What type of food do you eat onboard? Is the food good? How are the sleeping cabins? Do you share a room with someone else? (Devin, San Diego, CA)
Answer: To say the the food onboard is delicious would be a HUGE understatement. Mealtime on the Kilo Moana is truly one of the highlights of our daily routine. We are fed everything from king crab to filet mignon to veggie lasagna. Shawn is the chief steward onboard and he is assisted by Donnie and Jan. The three of them are very accommodating to all dietary requirements and restrictions. Each night we usually have two or three entree choices. It is a challenge for everyone onboard to maintain their weight, especially with the constant supply of cookies, cakes, ice cream, muffins, and danish that they bake daily! Shawn told me the ship goes through 20 pounds of bacon and 360 eggs a week! The living quarters onboard are probably smaller that you are used to at home, but they are certainly adequate. Two people share a sleeping cabin and two cabins share a bathroom. The space is a little small so you really have to be mindful of your roommate and be careful not to invade his/ her space.
Top: Dan Ohnemus throws a grappling hook to try and snag the drogue line. Bottom: After being hooked and passed to the back deck, a winch hauls the drogue array aboard.
Question of the day (January 20, 2007): How do you collect your water samples using the drogue? How do you get the drogue back on deck when you are done using it for the day? (Karen L., West Haven, CT) .
Answer: The drogue doesn't actually collect samples. It is just a way for us to follow the same mass of water. If we wanted to collect some water samples from where the drogue was located we would simply use the CTD rosette. When we are done using the drogue we bring it back on board through a pretty complex process. The pictures above depict how it is done. The captain initially brings the ship close to the drogue, but not too close! There is always a danger of lines getting caught in the propellers so we must be extremely careful to prevent this from happening. Next people stationed along the side of the ship throw grappling hooks (basically a big metal hook tied to a long line) in order to catch the drogue line. Once the drogue line is caught, the grappling line is passed to the back deck. From the back deck the grappling line is hooked to a winch and hauled aboard.
Top: Drogue array is placed on deck prior to deployment. 2nd from Top: Dan lowers the sock portion of the drogue off the back deck. 3rd from Top: Lawson hurls the hi-flyer buoy and radar beacon off the back deck and into the water. Bottom: The drogue is successfully deployed and on its own and being moved by the currents!
January 17, 2007: Today we are going to explain a piece of equipment that was deployed for the first time on this cruise. It is called a drogue. This piece of equipment is useful if you are interested in studying the same parcel of water over several hours or days. Remember that the water beneath the ship is constantly moving (think currents!). If the ship stays in one spot and continues sampling, but the water underneath the vessel keeps moving, each time we collect a sample it will be from a different parcel of water. By deploying a drogue we can follow the same parcel of water, thereby ensuring our samples can be compared to one another. The drogue basically consists of three major parts. The sock portion, the buoy and the radar beacon. The sock portion is the part that looks like a large tube. It acts almost like a parachute and gets pulled around by the currents under the ship. The sock is connected by a line or cable to the buoys. The buoys float on the surface of the water and allow us to see where the drogue is. The buoys also support the radar beacon and keep it above water. The radar beacon helps us to find the drogue if it should drift out of sight from the ship. After sampling is finished we can haul the drogue back in to use another day.
Left: Transmission electron micrograph of Prochlorococcus sp. Note the cell dividing into two on the left half of the image. Each cell is appoximately a micrometer in length, or about one millionth of a meter (Photo credit: C. Ting)
Question of Day: Is the Prochlorococcus sp. the scientists are studying classified as a plant or a protist or a monera or an archeobacteria? (Mrs. Prevenas's Seventh Grade Science Classes, Maui, Hawaii).
Answer: Prochlorococcus is a member of the cyanobacteria, which are bacteria that are capable of photosynthesis. Traditionally, the bacteria were grouped into the Kingdom Monera. However, with more recent genetic studies, it is becoming clear that rather than 5 Kingdoms, there are three Domains: Eukarya, Eubacteria, and Archaea. Eukarya is composed of the plants, animals, protists, and fungi (most, but not all are multicellular). The Eubacteria (bacteria) and Archaea are both microbes, but are as different from each other as we humans are to bacteria! Some of the other cyanobacteria that some of us are studying on this cruise, called Trichodesmium, are in fact multicellular, and "colonies" of them can be seen by the naked eye.
Left: Jeremy and Ryan haul in the CTD rosette. Right: Filters containing organisms collected from different depths in the water column.
Question of Day: Do you scoop [organisms] up with a micro-fine net or do you suck them up or what? (Liz Z., Michigan)
Answer (Part II): Yesterday we showed you a device called a plankton net that is used to collect some pretty small members of the planktonic community, but not the smallest! In order to collect the really small organisms (bacteria and viruses) we use what is called a CTD rosette. CTD stands for Conductivity-Temperature and Depth. These parameters are measured by electronics in the center of the package. This piece of equipment also has 24 bottles that surround the electronics and are initially cocked open. We can position the CTD at any depth in the water column using a crane and close the bottles using a computer on deck. This traps water from that depth within the closed bottles. We can then bring the water to the surface and filter the bacteria and viruses out of it. The second picture above shows 4 different filters with organisms from 3 different depths in the water column. The first filter on the left is brand new and does not have any organisms on it. The second filter from the left has organismsfound in water collected at 5 meters. The third filter from the left has organisms from 75 meters and the filter on the right has organisms from 200 meters depth. Note the differences in the color of the filters!
Question of Day: Do you scoop [organisms] up with a micro-fine net or do you suck them up or what? (Liz Z., Michigan)
Left: Copepod collected in plankton net viewed under a light microscope. Right: Dreux (left) and Annette (right) remove specimens from plankton net.
Answer: We use multiple techniques to collect different organisms of interest. Larger organisms like copepods are collected using a plankton net. This net is similar to a butterfly net and is dragged behind the ship to collect specimens. Things caught in the net are funneled down into a plastic jar that can be removed and brought back to the lab on the ship (Dreux is holding the plastic jar in her hands). Really small organisms like bacteria are too tiny to be caught by this type of device. Tomorrow we'll show you how we collect these microbes.
Question of Day: Why does the Kilo Moana have a funny shape (two hulls)? (Hokulani Elementary School)
Answer: The R/V Kilo Moana is from a class of ships referred to as swath vessels. The twin (two) hull design allows the ship to be more stable and move more efficiently through the water. In fact, the R/V Kilo Moana is so advanced that it was recently called one of ten "Super Ships" in the world by the Discovery Channel (Zackary Johnson, Chief Scientist, University of Hawaii).