//
you're reading...

Methodology

Science at Sea

The posts on oceanbites.org focus mostly on recently published scientific papers, and sometimes we don’t mention how the researchers got their data (it is often not the most entertaining part of the story). Sometimes it can seem like scientists just wave a wand and collect all their data! Unfortunately, real life is not like the world of Harry Potter- so how do scientists actually get to the end product of their research? First, they need to acquire their samples. For oceanographic research, many samples must come from (surprise, surprise) the ocean! This means researchers must collect water, rocks, or organisms they are interested in from the location in the ocean they are studying.

I just returned from a cruise aboard the R/V Endeavor , which is one of the National Science Foundation-owned vessels used for conducting scientific research. Scientists go on cruises to conduct all sorts of research (analyzing water chemistry, collecting different types of fishes, taking cores of ocean sediment, etc.) and those varied goals of research require different instruments. On this cruise, I had firsthand experience with a few common oceanographic instruments (as well as one brand new one!) that scientists use for conducting their research. Let’s take a look at how science is typically done on board a ship:

First things first – the days are long. Operating a ship is expensive and money doesn’t grow on trees, so every hour of ship time counts. Scientists must carefully plan which instruments can be deployed at specific times and make sure that samples are collected as efficiently as possible. For many scientists, this equates to working very long days (18+ in some cases!). So, guess you could say that one of the most important research instruments on a ship is the coffee pot!

The instrumentation: Scientists use a variety of tools to sample and collect data based on the needs of their research. My cruise focused on teaching us to use some of the basic instruments, which are summarized below.

Nets – Nets come in all sorts of shapes and sizes, and are made for with all sorts of different purposes (Figure 1). Nets can have varying mesh sizes, which are used to capture different organisms (think: you want to catch a bunch of big cod? Need a big mesh size. Want some plankton? Better use a much smaller mesh size).

Figure 1: Some of the different types of nets used for collecting samples. A) Large plankton net being deployed off the back of a research vessel (image from earthobservatory.nasa.gov). B) MOCNESS with multiple nets on a single frame (image from (www.gma.org). C) Isaacs-Kid Midwater trawl (image from www.hydrobios.de) and D) Bongo net- with two nets towed side by side (image from www.hydrobios.de).

Figure 1: Some of the different types of nets used for collecting samples. A) Large plankton net being deployed off the back of a research vessel (image from earthobservatory.nasa.gov). B) MOCNESS with multiple nets on a single frame (image from www.gma.org). C) Isaacs-Kid Midwater trawl (image from www.hydrobios.de) and D) Bongo net- with two nets towed side by side (image from www.hydrobios.de).

Some nets are controlled by onboard computers to close at a certain depth because in some cases, scientists only want to collect animals at a certain depth so they can be confident their samples are from the depth they care about. – Some nets are even fancier and include instruments to measure certain environmental conditions in the water (i.e. temperature) or have multiple nets all linked together on one frame to sample at multiple depths (MOCNESS, or multiple opening and closing net with environmental sensing system; Figure 1b). Scientists have to determine what type of organisms they want to collect and at what depths they need to sample in order to choose a proper net.

Figure 2: A) CTD package being deployed off the side of a research vessel (image from oceanexplorer.noaa.gov) B) scientist collecting water samples out of a Niskin bottle on the CTD (Image from www.schmidtocean.org).

Figure 2: A) CTD package being deployed off the side of a research vessel (image from oceanexplorer.noaa.gov) B) Scientist collecting water samples out of a Niskin bottle on the CTD (Image from www.schmidtocean.org).

CTD – (or Conductivity, Temperature, Depth Sensors; Figure 2). As the name suggests, this instrument senses salinity (measured via conductivity), temperature, and depth of the water. The CTD is attached to a large frame (called a rosette) which holds a bunch of water sampling bottles (called Niskin bottles). Occasionally, other probes are also attached to the rosette, such as oxygen or fluorescence meters. The instrument is deployed using one of the boat’s winches and is then lowered to the desired depth. As the instrument descends, CTD probes gather information about the physical and chemical properties of the water. Scientists can use these physical and chemical properties to determine where they would like to collect water samples. To do this, someone on board the ship tells the CTD to close one of the Niskin bottles, trapping water from that depth. The scientists can now move to a new depth, close another Niskin bottle, and continue until all samples have been taken. Once the instrument is pulled back onto the ship, scientists can collect the water samples from the different depths to use for their analyses.

Figure 3: The Wire Flyer developed by scientists at the University of Rhode Island’s Graduate School of Oceanography (image from gregory-designs.com).

Figure 3: The Wire Flyer developed by scientists at the University of Rhode Island’s Graduate School of Oceanography (image from gregory-designs.com).

The Wire Flyer – This is a relatively new instrument for oceanographic sampling (Figure 3). It was developed by scientists at the University of Rhode Island’s Graduate School of Oceanography. Dr. Chris Roman and some of his colleagues were on board testing out their device and making sure it was ready to take out for future data collection. See Chris Roman explain the concept behind his device in this video.

This device measures similar properties to the CTD. The difference is that, instead of descending to a depth once and sampling within that same horizontal profile like a CTD, the wire flyer is towed behind the boat, “flying” up and down on a wire- increasing the area sampled within the water column.

Figure 4: a yummy tie dye cake (image from http://birdonacake.blogspot.com/2012/02/rainbow-tie-dye-cake.html)

Figure 4: a yummy tie dye cake (image from http://birdonacake.blogspot.com/2012/02/rainbow-tie-dye-cake.html)

To give you an idea of why the wire flyer is different from other instruments, let’s take a more manageable example: You get one of these cool tie dye cakes for your birthday (Figure 4). You want to know which colors are where in the cake. To do this, you are given a single slice of the cake. You can see that the colors are stacked: red, yellow, green, blue, purple from top to bottom. But you have no idea if the colors are layered that way throughout the cake. To get a better idea you take another slice and find the layers are now red, orange, green, yellow, blue, purple – different from before. The more and more slices of cake you take, the clearer the picture you get about the composition of the whole cake.

Same with oceanographic testing – the CTD essentially takes a single piece of cake (one profile of the ocean), while the Wire Flyer is able to keep going back and grabbing more pieces to get a better picture of the actual composition of the ocean.

Conclusion:

A lot of hard work goes into gathering the samples needed to conduct research. Scientists use instruments like those explained here to collect the samples for their specific research project. The data collected from experiments at sea can be taken back to the lab, analyzed, and published in articles like the ones we share with you on oceanbites.org.

This cruise was sponsored by Rhode Island Teachers at Sea to teach Rhode Island grade school teachers about this scientific process. To see more about the cruise and to get the perspective from the teachers involved visit: http://www.gso.uri.edu/rieducatorscruise/ or watch this video the teachers put together, documenting their experience on board the R/V Endeavor.

Discussion

One Response to “Science at Sea”

  1. I was lucky enough to accompany some grad students aboard the RV Cap’n Bert recently, as they surveyed the bottom of Narragansett Bay. The story is on my blog, “Science and Nature for a Pie.”

    http://scienceandnatureforapie.com/what-lies-beneath-uri-surveys-rhode-island-waters/

    Posted by Hugh Markey | August 28, 2015, 8:02 pm

Post a Comment

Instagram

  • by oceanbites 2 weeks ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 1 month ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 2 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 3 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 3 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 3 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 4 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 4 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 4 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 5 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 6 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 6 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 7 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 7 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 8 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 8 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 9 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
  • by oceanbites 9 months ago
    Feeling a bit flattened by the week? So are these summer flounder larvae. Fun fact: flounder larvae start out with their eyes set like normal fish, but as they grow one of their eyes migrates to meet the other and
WP2Social Auto Publish Powered By : XYZScripts.com