Open source. Open science. Open Ocean. Oceanography for Everyone and the OpenCTD

Andrew compares the OpenCTD readout to a hand refractometer, because apparently he's a hipster ecologist.

Andrew compares the OpenCTD readout to a hand refractometer, because apparently he’s a hipster ecologist.

Nearly four years ago, Kersey Sturdivant and I launched a bold, ambitious, and, frankly, naive crowdfunding initiative to build the first low-cost, open-source CTD, a core scientific instrument that measures salinity, temperature, and depth in a water column. It was a dream born from the frustration of declining science funding, the expense of scientific equipment, and the promise of the Maker movement. After thousands of hours spent learning the skills necessary to build these devices, hundreds of conversations with experts, collaborators, and potential users around the world, dozens of iterations (some transformed into full prototypes, others that exist solely as software), and one research cruise on Lake Superior to test the housing and depth and temperature probes, the OpenCTD has arrived.

Kersey strike a pose while deploying an OpenCTD in our local estuary.

Kersey strikes a pose while deploying an OpenCTD in our local estuary.

Over the last week, Kersey and I have been hard at work building a battery of CTDs while methodically documenting the construction process. You can watch the event unfurl on the #HackTheOcean hashtag. We now have three new CTDs ready to be distributed to collaborators at various institutions for more field tests and, in particular, to assess the precision of three different conductivity probes, all of which have been calibrated and validated here, in Virginia.

OpenCTD versus commercial CTD temperature and depth test. Conductivity test are occurring this summer, but initial surveys indicated no significant deviation from commercial instruments (indeed, we’re even using a commercial conductivity circuit that has been thoroughly tested in other environmental monitoring contexts.)

Now, finally, after 4 years of challenges and opportunities, of redesigns, re-education, and re-development, it’s time for you to join our open-source community of Citizen Oceanographers and build your own OpenCTD!

We’ve hosted the entire build guide, as well as the software, 3D printer files, support documentation, and raw data from our first research cruise in the Oceanography for Everyone GitHub repository, where you can also find guides and designs for the BeagleBox field computer and the Niskin3D 3D-printable Niskin bottle. 3D print files are also available on Thingiverse, if you’re more comfortable with that platform. We’ve also gone out of our way to make the build as simple as possible. You’ll need to learn basic programming and electronics, but the technical aspects of building your own CTD shouldn’t be a barrier to entry.

Over these four years, the OpenCTD has grown from a single project to a community of citizen oceanographers committed to making the tools needed to study the oceans as accessible as possible. As my friend and colleague Eric Stackpole said upon launching the first OpenROV kickstarter:

“Ocean exploration shouldn’t require a research grant, it should require curiosity.”


Since launching, numerous people have asked us if we can build an OpenCTD for them. We are not really set up to be a manufacturer of CTDs, however, get in touch with either me ([email protected]) or Kersey ([email protected]) and we can talk about holding an OpenCTD training workshop with your institution or organization.

The Ocean belongs to everyone. Shouldn’t we all have access to the tools needed to study it?

Oceanography for Everyone – The OpenCTD

I believe that scientific research should have as few barriers to participation as possible. I believe that not only should the results of scientific research be freely available to the public, but that the tools–software, hardware, and expertise–of science should be made as accessible as possible. In many cases, this is not possible. A sequencer costs what a sequencer costs. Stable isotope analysis comes with a heavy price tag. A Ph.D. requires a massive investment in time and energy and subsequently comes with implicit authority over a subject matter. But where the gates can be thrown open, they should be thrown open.

The Ocean belongs to everyone. Above almost any other resource, the ocean is the common property of all humankind. The tools to study the ocean–vessels and instruments–are expensive, and this expense creates an unacceptably high barrier to entry for anyone interested in studying the ocean.

I genuinely believe that all ocean stakeholders–scientists, commercial fishers, recreational users, industry, conservation NGO’s, mariners of all stripes–have something valuable to contribute to our ongoing understanding of the ocean. For this reason, above all else, myself and a small team are building open-source oceanographic instruments that are low-cost and accurate enough for robust, scientific studies.

The first device, which has been mentioned numerous times here and elsewhere, is the OpenCTD.

Conductivity, temperature, and depth (CTD). With these three measurements, marine scientists can unlock ocean patterns hidden beneath the waves. The ocean is not uniform, it its filled with swirling eddies, temperature boundaries, layers of high and low salinity, changing densities, and many other physical characteristics. To reveal these patterns, oceanographers use a tool called the CTD. A CTD is found on almost every major research vessel. Rare is the scientific expedition–whether it be coastal work in shallow estuaries or journeys to the deepest ocean trenches–that doesn’t begin with the humble CTD cast.

The CTD is not cheap. Commercial CTD’s start at more the $5,000 and can climb as high as $25,000 or more.

We believe that the prohibitive cost of a CTD is an unacceptable barrier to open science. The price tag excludes individuals and groups who lack research grants or significant private funds from conducting oceanographic research. We want to make this tool–the workhorse of oceanographic research–available to anyone with an interest in the oceans.

We’re building a CTD. 

We have reached the final week of our fund raising campaign, having raised slightly more than 50% of our goal, and we need your help. If you believe in open-source oceanography and open science, please consider donating to Oceanography for Everyone. Every dollar helps.

Together, we can explore the open ocean.

Oceanography for Everyone – The OpenCTD

Two weeks left to Support the OpenCTD and help us build an oceanographic tool for everyone!

Wow! Since we launched the OpenCTD we’ve raised nearly $4,000 to help develop an oceanographic tool the anyone can build. But $4,000 is only 40% of our funding goal, and we’ve got 12 days left to fund the rest of the project. If you believe in open source oceanography, think to tools of scientific research should be available to everyone, or just think a low-cost CTD would be a great addition to your research, teaching, or recreational activities, consider contributing to the OpenCTD. Even a few dollars will help us reach our goal.

Over the last month, I’ve talked to dozens of excited contributors with their own ideas for OpenCTD Projects. Here are a few of the most exciting:

  • Equip participants in catch-and-release fishing tournaments with an OpenCTD, so that they can take water column data and correlate it with presence of large pelagic fish. This would provide even greater insight into the movement, behavior, and migration patterns of hard-to-sample species.
  • Incorporate the OpenCTD into a SCUBA divers’ standard kit, so that your dive profile includes conductivity as well as temperature and depth. This would allow divers to discover local variability in the water column and correlate it with observations of marine life.
  • Affix the OpenCTD to commercial shrimp trawlers, so the fishermen can more accurately track the depth of their gear and determine which oceanographic conditions produce the best shrimp catches and the least by-catch.
  • Run an oceanographic “Big Year” challenge to promote open-source data by having private citizens compete to produce the most high-resolution data from a full seasonal cycle.
  • Put a CTD in every coast-, estuary-, river-, and lake-adjacent classroom, so that students have easy access to the tools necessary to explore their local aquatic ecosystems.

I want to see all of these projects, and more, come to fruition, but in order to make them happen, we need funding to finish developing the instrument. We have a proof-of-concept prototype, but through discussions with our donors and supporters, have developed even better systems to produce accurate, high-resolution data at low cost.

What does an OpenCTD mean to marine ecologists?

kerseysquaeThe OpenCTD–a conductivity-temperature-depth (or CTD) sonde is considered the ‘work-horse’ of oceanography. Three relatively simple probes constitute the CTD and allow researchers to make basic water quality measurements. These fundamental measurements are the foundation upon which marine science is built.  As was aptly stated by Dr. Thaler, “Rare is the scientific expedition–whether it be coastal work in shallow estuaries or journeys to the deepest ocean trenches–that doesn’t begin with the humble CTD cast.” CTD’s are commercially produced by a number of companies, but the associated cost of purchasing one of these instruments (ranging from $5,000 to $25,000) is an unacceptable barrier of entry into marine science. Thus the OpenCTD project—an attempt to construct a low-cost CTD that is scientifically applicable—was born.. Our goal is to produce free blue-prints, instructions, and schematics for the physical construction and calibration of a low-cost, open-source CTD.  The final cost of the device will be low enough (~$200) to be readily accessible to those interested in constructing one, regardless of financial limits.

Read More

OpenCTD first soak test

Two weeks ago, we launched Oceanography for Everyone–The OpenCTD, a crowdfunding project to develop a low-cost, open-source CTD. After a few days hunting around for the best sealants, I put the prototype (name pending, suggestions welcome) through its first soak test.

IMG_4531

OpenCTD first soak test. Please ignore how dirty my tub is.

The results were… mixed. I left the CTD soaking for 12 hours (with hardware removed) to see if there was any water incursion. Unfortunately, it seems like there is a small leak around the cap pipe cap. Total water incursion after 12 hours was less than 1 ml, but for us, that isn’t acceptable. Fortunately, we have a couple solutions in the works. For the prototype, we’re planning on adding teflon plumbers tape and additional sealant to help fill the voids. Longterm, we’re looking into a different cap assembly that would allow us to incorporate an O-ring into the assembly.

Developing a low-cost, open-source CTD costs time and money. You can helps us achieve our goal of making oceanography accessible to everyone by funding our Rockethub project–The OpenCTD.

What can we do with an OpenCTD – high resolution hurricane monitoring

Last Friday we launched Oceanography for Everyone–The OpenCTD, a crowdfunding project to develop a low-cost, open-source CTD. This project won’t succeed without your help. To demonstrate how valuable a device like the OpenCTD is, for the next several weeks I’ll be presenting various projects that could be accomplished with access to low-cost CTD’s. First up on the docket is an array of volunteer nodes to measure the effects of hurricanes.

Imagine a category 2 hurricane barreling down the eastern seaboard. As the swirling air mass builds strength, it absorbs heat from the ocean. The powerful winds alter local currents, mixing layers of seawater, and depositing freshwater on the surface in the form of rain. The effects of a hurricane reach far beyond the eye of the storm and changes may take several months to return to the status quo.

Wouldn’t it be awesome if there were a group of enthusiastic (and safety minded) volunteers taking ocean measurements before* and after the hurricane passed? And not just on the regional scale like we do now, but at an extremely high resolution, charting changes in local estuaries, sounds, and dozens or hundreds (or, dare I dream, thousands) of points along the coast? Enthusiastic volunteers with access to their own local waterways and a low-cost CTD could monitor these water bodies for months following the storm, documenting changing sea conditions. Uploaded to a shared database like Marinexplore, this kind of data would provide a massive baseline for assessing hurricane impacts, anticipating recovery, and informing management of affected marine populations.

A low-cost, open-source CTD could help make this kind of large-scale monitoring project possible. With your help, we can make the OpenCTD a reality.

Please visit our Rockethub project page and consider donating (even a few dollars helps!). You can also follow us on our Google+ page–Oceanography for Everyone for project updates and additional media.


*While, of course, maintaining a conservative window of time to evacuate ahead of the storm.

Oceanography for Everyone – Help us build a CTD!

Head over to our Rockethub Page for more information!

Conductivity, temperature, and depth (CTD). With these three measurements, marine scientists can unlock ocean patterns hidden beneath the waves. The ocean is not uniform, it its filled with swirling eddies, temperature boundaries, layers of high and low salinity, changing densities, and many other physical characteristics. To reveal these patterns, oceanographers use a tool called the CTD. A CTD is found on almost every major research vessel. Rare is the scientific expedition–whether it be coastal work in shallow estuaries or journeys to the deepest ocean trenches–that doesn’t begin with the humble CTD cast.

The CTD is not cheap. Commercial CTD’s start at more the $5,000 and can climb as high as $25,000 or more.

We believe that the prohibitive cost of a CTD is an unacceptable barrier to open science. The price tag excludes individuals and groups who lack research grants or significant private funds from conducting oceanographic research. We want to make this tool–the workhorse of oceanographic research–available to anyone with an interest in the oceans.

We’re building a CTD, but we need your help!

The ocean belongs to us all. Let’s ensure that we have access to the tools needed to study it.

Head over to our Rockethub Page for more information!