you're reading...


Smart sampling of the world’s oceans

Costello, M. J., Basher, Z., Sayre, R., Breyer, S., & Wright, D. J. (2018). Stratifying ocean sampling globally and with depth to account for environmental variability. Scientific reports, 8(1), 11259.

The ocean is a gigantic environment, covering more than two thirds of the Earth’s surface. It is so big, the word “ocean” has come to describe something that is very large or unlimited in size: Love as deep as the ocean, a drop in the ocean, an ocean of people. Besides being an evocative part of our lexicon, the ocean is also a critical component of eco- and climate systems at just about every scale (check out any of the other articles on this blog!).

Figure 1 – The average range of temperature and oxygen in the global ocean. Notice how slowly both values vary below 1000 meters (Adapted from Costello et al., 2018).

Measuring and monitoring the world’s vast seas is a highly involved, enormous task. How do you go about observing a body of water so immense and complex? There are many dedicated scientists, using an array of methods and tools, attempting to do so. But even with an army of researchers and a navy of vessels, no one could ever hope to capture the whole picture. Researchers necessarily have to economize and deploy their limited resources in a principled way.

Like many other oceanographers, Dr. Mark Costello of the University of Auckland recognized that there is no realistic way that the oceanographic community could densely sample the ocean at every point. He and several colleagues sought a scientifically grounded framework to manage resources for ocean observation. They hope that a principled approach, applied by the community at-large, could facilitate better ocean observing. Such a scheme would need to take into account the range of scales that phenomena occur on: El Niños take place over the entire Pacific Basin on a roughly 10 year cycle. But eddies can mix things up over a few kilometers and last a matter of days to several months. Further complicating observation efforts is that these processes all interact with each other in subtle ways.

Figure 2 – Global maps outlining the contours of the proposed EMUs. Each number and color corresponds with a different zone. Each panel is a slice at a different depth (adapted from Costello et al., 2018).

In their recent Scientific Reports paper, Costello and his team proposed that ocean sampling be stratified, or divided, based on longitude, latitude, depth, and time. The basic insight of their approach is that the time-scale of change in the ocean is different depending on where you are looking. Physical and chemical shifts in water at the ocean surface, for example, happen more rapidly then in the midwater. Costello makes clear that this does not mean that one zone is more important than another. His point is rather that more slowly varying waters do not need to be sampled as frequently as those that turn over quickly.

Consider the global average of temperature, oxygen, and current speed as a function of depth (fig. 1). Both parameters fluctuate rapidly in the upper 1000 meters of the ocean, but are stable almost all the way to the bottom. There is, of course, huge amounts of regional variability. But, in the aggregate, the middle of the ocean is pretty quiet.

Costello and his team analyzed a suite of such environmental parameters to propose dividing the ocean into Ecological Marine Units (EMUs). The group suggests that the ocean can be separated into 37 distinct EMUs, each with a unique physical and chemical signature (fig. 2). Costello makes no particular prescriptions on how to design studies or appropriately deploy monitoring resources in these regions. He merely proposed them as a tool and guiding principle.

The ocean is a challenging part of the world to study – it is vast, deep, difficult to access, and expensive to sample. It behooves the scientific and policy-making communities to carefully consider how to use their resources – financial and human – to best study the sea. We do not want to miss anything, but we also cannot observe everything, all the time. Costello’s EMUs might not be the ideal way to find the balance between desire and reality. But it is a start. And one that could lead us in the right direction.


No comments yet.

Post a Comment


  • by oceanbites 3 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 4 months 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 5 months 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 6 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 6 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 7 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 7 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 8 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 8 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 8 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 8 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 9 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 9 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 9 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 10 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 11 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 11 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 12 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 12 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 1 year 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 
WP2Social Auto Publish Powered By : XYZScripts.com