The ways scientists study the oceans become more and more sophisticated over time. To keep pace with their curiosity, oceanographers must often invent devices capable of helping them observe very specific phenomena. Here are five new instruments in the Scripps arsenal that are transforming the way we see the Blue Planet.
Name: ZRay Glider
Chief Scientist: Gerald D’Spain
Function: Listening to sounds in the ocean
Detecting and identifying ocean sounds has been a mission of ocean acousticians, geophysicists, marine bioacousticians, and sonar signal/array processors at Scripps since before World War II. Today, passive acoustic sensing provides improved understanding of ocean properties and processes, but gaps in knowledge still exist in several important areas.
A novel method for simultaneously collecting a wide range of ocean acoustic and environmental data is now available thanks to an eight-year effort from the Flying Wing Autonomous Underwater Glider team. This team, led by Scripps, also includes members from the Applied Physics Lab at the University of Washington, and the Space and Naval Warfare Systems Center Pacific.
Their product is the flying wing-shaped ZRay glider, funded by the Office of Naval Research. This glider has been designed exclusively by members of the Flying Wing glider team, and constructed by the machine shops at Scripps’s Nimitz Marine Facility in Point Loma and its La Jolla campus. The autonomous programmable craft with a 6-meter (20-foot) wingspan provides constant acoustic sensing with a 27-element hydrophone array installed in a sonar dome in the glider’s leading edge. In addition, there are very wide-band acoustic sensors in the nose, tail, and wingtips. Environmental sensors presently include ocean salinity and temperature sensors. The autonomous platform is designed for missions lasting up to a month and covering distances greater than 1,000 kilometers (600 miles).
Knowledge from the data collected by the onboard sensors open up possibilities for new studies of a wide variety of ocean phenomena. We could say more about how it could also improve detection of phenomena of military interest – but that’s classified.
Name: Deep SOLO
Chief Scientist: Dean Roemmich
Function: Taking the “Vital Signs” of the Deep Ocean
A network of more than 3,600 floats distributed more or less evenly throughout the world’s oceans is in the midst of transforming how we understand them. Called Argo, the network’s existence was enabled in the late 1980s by floats developed by Scripps scientists known by the acronym SOLO. Now SOLOs and similar types of Argo floats record the “vital signs” of the oceans: temperature, salinity, and current speed and direction. Collectively they are enabling oceanographers to observe oceans at global scales and will over time provide complete records of cycles that span decades.
Present-day Argo floats, however, are programmed to monitor only what’s happening in the top 2,000 meters (6,500 feet) of the oceans even though the average depth is twice that. Now a new float, appropriately named Deep SOLO, is opening up new expanses to real-time monitoring. Deep SOLO is intended to make profiles from the ocean surface to the ocean bottom, at depths of up to 6,000 meters (almost 20,000 feet).
What’s to be discovered at that depth? The upper oceans are often referred to as the “memory” of climate since they store heat energy for much longer than the atmosphere, taking years or decades to respond to changes in the climate system. If the upper oceans are climate’s memory, the deep oceans are their subconscious, being the repositories of even longer-term changes in the heating or cooling of the Earth.
Scripps physical oceanographer Dean Roemmich, a lead Argo scientist, said network operators will not deploy as many Deep SOLO units as their upper-ocean kin and their focus will be on observations of decadal-scale and longer processes. Prototype deployments of Deep SOLO floats have begun and the first regional Deep SOLO array could be deployed in 2014.
According to Roemmich, “The top-to-bottom profiles of temperature and salinity from Deep Argo will provide data needed to complete the climate system’s heat budget and to understand how much of global sea level rise is due to heating and expansion of seawater.”
Chief Scientist: Todd Martz
Function: Measuring Ocean Acidification in the Field
Perhaps the past decade’s most alarming oceanographic discovery is that the oceans are acidifying at an unprecedented rate, thanks to the seas’ accelerated uptake of carbon dioxide created by fossil fuel use. Though one current study directly linked acidification to the depletion of farmed oysters in the Pacific Northwest, much of what researchers know about ocean acidification comes not from the field, but rather from laboratory experiments. Until recently, it was extremely difficult to autonomously and accurately record ocean pH. To overcome that hurdle, the SeapHOx was conceived.
The SeapHOx can measure not only the pH of seawater but other crucial parameters such as dissolved oxygen, temperature, and salinity. Similar to how atmospheric changes in carbon dioxide and oxygen go hand-in-hand due to photosynthesis and respiration cycles, so too do oceanic changes in pH and oxygen. Martz has built more than 100 SeapHOx and similar SeaFET units in collaboration with oceanographers and marine biologists at several other research centers. The units have been deployed in icy seawater in both Arctic and Antarctic seas, in the Pacific and Atlantic Oceans, and in the Mediterranean Sea and the Gulf of Mexico. These sensors are helping scientists discover how rapidly pH changes naturally. Determining natural variability provides a critical reference on which to frame scientists’ understanding of effects of ocean acidification and give them more insight into what future changes in ocean chemistry as a result of human activities might mean for the creatures living in the world’s oceans.
Name: Underwater Reflectance Microscope
Chief Scientist: Jules Jaffe
Function: Observing marine microorganisms without removing them from their habitat
Many of the most important biological processes in the ocean take place at a microscopic scale, but when scientists remove organisms from their native habitats to study them in the lab, much of the information and its context are lost. Scripps research oceanographer Jules Jaffe is seeking to overcome this challenge by developing several types of underwater microscopes that can image microorganisms in their natural settings without disturbing them. One such microscope is aimed at imaging benthic habitats such as coral reefs. Designed by postdoctoral researcher Tali Treibitz and Ph.D. student Andrew Mullen, this instrument will allow the first scientific study of sub-millimeter scale processes as they occur naturally on the reef.
This new microscope will enable scientists to explore ecologically significant phenomena important to reef health. One example is the interaction between corals and their symbiotic zooxanthellae, single-celled algae that normally live symbiotically inside the coral polyp where they provide their hosts energy through photosynthesis. Researchers have known that when ocean conditions such as water temperature are altered, that relationship can become strained. Excessively warm water can cause the normally beneficial microorganism to malfunction, which in turn triggers corals to eject them to the detriment of both parties. The result is bleaching, the most visible sign of dying coral reefs. The microscope could bear witness to this eviction process in a natural setting for the first time. It can also record the turf battle between coral and algae, one that corals are increasingly losing in the face of over-fishing and climate change. The research team plans to examine some of these questions during its first deployment of the microscope in November 2013 in the Red Sea.
Jaffe’s lab is collaborating with several others on the project, including the Coral Ecology Lab led by Scripps Oceanography marine biologist Jennifer Smith and Jurgen Schulze of UC San Diego’s Qualcomm Institute, who is supporting 3D renderings and large screen visualizations of the images.
Chief Scientist: Dan Rudnick
Function: Observing Ocean Data along Predetermined Transects
Though this programmable glider has actually been around for more than 15 years, Spray earns a special lifetime achievement award for assembling an incredible body of data during that period and for the milestone it has just passed. Spray gliders have now made the equivalent of 10 laps around planet Earth while gathering ocean profiles that were nearly impossible to obtain two decades ago. The gliders are equipped with temperature and salinity sensors as well as other mission-specific instruments such as backscatter monitors used for detecting the abundance of zooplankton or fluorometers that measure amounts of phytoplankton. Researchers pre-program the course of the gliders, the buoyancy of which is controlled through hydraulic pumps that change their volume as needed. Sprays can be deployed in ocean regions that would be prohibitively shallow for Argo floats (see above entry) and can stay in the water for several months, conserving energy by never travelling faster than 0.5 knots, thus reducing drag.
Currently 12 Sprays are deployed in locations ranging from the California Current to the Solomon Sea. Oceanographer Dan Rudnick said deployments are planned in the Bay of Bengal and off the Galapagos Islands this year as the fleet sets in on its eleventh collective circumnavigation of the planet.
– Robert Monroe