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By NASA
6 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA astronauts Michael Barratt, Matthew Dominick, and Jeanette Epps and Roscosmos cosmonaut Alexander Grebenkin are returning to Earth after months aboard the International Space Station conducting scientific experiments and technology demonstrations for the agency’s SpaceX Crew-8 mission. The four launched on March 3 aboard a SpaceX Dragon spacecraft from NASA’s Kennedy Space Center in Florida.
Here’s a look at some scientific milestones accomplished during their mission:
Revealing resistant microorganisms
NASA astronaut Jeanette Epps extracts DNA for the Genomic Enumeration of Antibiotic Resistance in Space experiment, which surveys the station for antibiotic-resistant organisms and sequences their DNA to examine adaptations to space. Results could support development of measures to protect astronauts and people in buildings and facilities on Earth, such as hospitals, from resistant bacteria.
NASA Brain organoid models
NASA astronaut Mike Barratt processes samples for Human Brain Organoid Models for Neurodegenerative Disease & Drug Discovery. This investigation uses human brain organoids created with stem cells from patients to study neuroinflammation, a common feature of neurodegenerative conditions such as Parkinson’s disease. The organoids provide a platform to study these diseases and their treatments and to potentially address how extended spaceflight affects the brain.
NASA Bioprinting human tissues
Tissue samples bioprinted in microgravity are higher quality than those printed on the ground. NASA astronaut Matthew Dominick processes cardiac tissue samples for the Redwire Cardiac Bioprinting Investigation. Results could advance the production of organs and tissues for transplant and improve 3D printing of foods and medicines on future long-duration space missions.
NASA Growing better drugs
NASA astronaut Mike Barratt works on Pharmaceutical In-space Laboratory – 02, which uses the station’s Advanced Space Experiments Processor to study how microgravity affects the production of various types of protein crystals. The ability to produce better crystals could lead to manufacturing improvements and new applications and better performance for pharmaceutical compounds, potentially providing more positive patient experiences.
NASA Alloy solidification
NASA astronaut Jeanette Epps works on Materials Science Lab Batch 3a, two projects investigating the solidification of metallic alloys in space. Insights gained could help improve alloy solidification processes on the ground, supporting the development of materials with superior chemical and physical properties for applications in space and on Earth.
NASA Fueling the flames
The Solid Fuel Ignition and Extinction- Growth and Extinction Limit investigation determines how fuel temperature affects material flammability. This image shows the fuel surface during a burn (the black part of the sphere) and the distance traveled by the flame (blue). Results could improve researchers’ understanding of fire growth and inform the development of optimal fire suppression techniques to protect crews on future missions.
NASA Very long-distance calls
NASA astronaut Jeanette Epps wraps up an ISS Ham Radio session on April 10, with students in Italy. The program connects students and enthusiasts with astronauts in space via amateur radio. Participants study space, radio waves, and related topics to prepare questions before their scheduled call.
NASA Student robotics competition
For Astrobee-Zero Robotics, students compete to have their code control one of the space station’s Astrobee robots. The experience helps inspire the next generation of scientists, engineers, and explorers. NASA astronaut Mike Barratt works with the Astrobee robot named Bumble during operations for the project.
NASA Immune function in space
NASA astronaut Jeanette Epps prepares samples for Immunity Assay, a study of how spaceflight affects immune function. Previously, astronaut immune function could only be examined pre- and postflight, but a newly developed assay allows for testing during flight. This capability provides a more precise assessment of the immune changes that happen in space.
NASA Getting weighed in weightlessness
The Space Linear Acceleration Mass Measurement Device calculates a crew member’s mass based on Newton’s Second Law of Motion, which states force equals mass times acceleration. NASA astronaut Matthew Dominick performs maintenance on the device, used in support of multiple NASA and ESA (European Space Agency) investigations on how spaceflight affects the body.
NASA Satellites for science
NASA astronaut Mike Barratt prepares for the Nanoracks Cubesat Deployer Mission 27on April 16. The mission deployed seven research satellites: a reflectometer to measure sea ice, tests of telemetry instruments and solar cells, a hyperspectral thermal imager, a gamma-ray burst detector, a new remote sensing technique, and a magnetic field measurement test.
NASA Remote-controlled robots
NASA astronaut Jeanette Epps remotely manipulates a robot on the ground for Surface Avatar. The investigation tests system ergonomics, operator response to feedback, and the potential challenges for actual orbit-to-ground remote control. Such operation is an important capability for future exploration missions to the Moon and Mars.
NASA The power of photographs
NASA astronauts Mike Barratt, Matthew Dominick, and Loral O’Hara take photographs in the station’s cupola, adding to the more than 4.7 million images produced for Crew Earth Observations. These images support scientific studies on topics ranging from aquatic organisms and icebergs to the effects of artificial lighting at night and inform the response of decision-makers to natural disasters such as volcanoes and floods.
NASA Reflections on the Moon
For Earthshine from ISS, astronauts photograph the Moon throughout the lunar cycle to study changes in the light it reflects from Earth. Results could help validate the concept of observing Earth’s climate from satellite-borne instruments and add to researchers’ understanding of how the planet’s climate is changing.
NASA Packing a Dragon
NASA astronauts Matthew Dominick and Tracy C. Dyson pack frozen samples into the SpaceX Dragon spacecraft for return to Earth and analysis by researchers. The spacecraft launched to the orbiting laboratory on March 21 for NASA’s SpaceX 30th commercial resupply services mission, carrying scientific experiments and supplies, and returned to Earth on April 30.
NASA Cygnus delivers
Northrop Grumman’s Cygnus cargo spacecraft attached to the Canadarm2 robotic arm before being released from the space station on July 12. NASA’s Northrop Grumman 20th commercial resupply services mission arrived Feb. 1 with experiments on 3D printing, robotic surgery, tissue cartilage, and more.
NASA Melissa Gaskill
International Space Station Research Communications Team
NASA’s Johnson Space Center
Download high-resolution photos and videos of the research mentioned in this article. Search this database of scientific experiments to learn more about those mentioned in this article.
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By NASA
On Sept. 30, 1994, space shuttle Endeavour took to the skies on its 7th trip into space. During the 11-day mission, the STS-68 crew of Commander Michael A. Baker, Pilot Terrence “Terry” W. Wilcutt, and Mission Specialists Steven L. Smith, Daniel W. Bursch, Peter J.K. “Jeff” Wisoff, and Payload Commander Thomas “Tom” D. Jones operated the second Space Radar Laboratory (SRL-2) as part of NASA’s Mission to Planet Earth. Flying five months after SRL-1, results from the two missions provided unprecedented insight into Earth’s global environment across contrasting seasons. The astronauts observed pre-selected sites around the world as well as a volcano that erupted during their mission using SRL-2’s U.S., German, and Italian radar instruments and handheld cameras.
Left: The STS-68 crew patch. Right: Official photo of the STS-68 crew of Thomas D. Jones, front row left, Peter J.K. “Jeff” Wisoff, Steven L. Smith, and Daniel W. Bursch; Michael A. Baker, back row left, and Terrence W. Wilcutt.
In August 1993, NASA named Jones as the SRL-2 payload commander, eight months before he flew as a mission specialist on STS-59, the SRL-1 mission. When NASA could not meet JPL’s request to fly their personnel as payload specialists on the SRL missions, the compromise solution reached had one NASA astronaut – in this case, Jones – fly on both missions. Selected as an astronaut in 1990, STS-59 marked Jones’ first flight and STS-68 his second. In October 1993, NASA named the rest of the STS-68 crew. For Baker, selected in 1985, SRL-2 marked his third trip into space, having flown on STS-43 and STS-52. Along with Jones, Wilcutt, Bursch, and Wisoff all came from the class of 1990, nicknamed The Hairballs. STS-68 marked Wilcutt’s first spaceflight, while Bursch had flown once before on STS-51 and Wisoff on STS-57. Smith has the distinction as the first from his class of 1992 – The Hogs – assigned to a spaceflight, but the Aug. 18 launch abort robbed him of the distinction of the first to actually fly, the honor going instead to Jerry M. Linenger when STS-64 ended up flying before STS-68.
Left: The Spaceborne Imaging Radar-C (SIR-C) in Endeavour’s payload bay in the Orbiter Processing Facility at NASA’s Kennedy Space Center in Florida. Middle: Endeavour on Launch Pad 39A. Right: STS-68 crew in the Astrovan on its way to Launch Pad 39A for the Terminal Countdown Demonstration Test.
The SRL payloads consisted of three major components – the Spaceborne Imaging Radar-C (SIR-C), built by NASA’s Jet Propulsion Laboratory in Pasadena, California, the X-band Synthetic Aperture Radar (X-SAR) sponsored by the German Space Agency DLR and the Italian Space Agency ASI, and the Measurement of Air Pollution from Satellites (MAPS), built by NASA’s Langley Research Center in Hampton, Virginia. Scientists from 13 countries participated in the SRL data gathering program, providing ground truth at preselected observation sites. The SIR system first flew as SIR-A on STS-2 in November 1981, although the shortened mission limited data gathering. It flew again as SIR-B on STS-41G in October 1984, and gathering much useful data.
Building on that success, NASA planned to fly an SRL mission on STS-72A, launching in March 1987 into a near-polar orbit from Vandenberg Air Force, now Space Force, Base in California, but the Challenger accident canceled those plans. With polar orbits no longer attainable, a 57-degree inclination remained the highest achievable from NASA’s Kennedy Space Center (KSC) in Florida, still allowing the radar to study more than 75% of Earth’s landmasses. As originally envisioned, SRL-2 would fly about six months after the first mission, allowing data gathering during contrasting seasons. Shuttle schedules moved the date of the second mission up to August 1994, only four months after the first. But events intervened to partially mitigate that disruption.
Left: Launch abort at Launch Pad 39A at NASA’s Kennedy Space Center in Florida. Right: A few days after the launch abort, space shuttle Discovery arrives at Launch Pad 39B, left, with space shuttle Endeavour still on Launch Pad 39A, awaiting its rollback to the Vehicle Assembly Building.
Endeavour arrived back at KSC following its previous flight, the STS-59 SRL-1 mission, in May 1994. Workers in KSC’s Orbiter Processing Facility refurbished the SRL-1 payloads for their reflight and serviced the orbiter, rolling it over to the Vehicle Assembly Building (VAB) on July 21 for mating with its External Tank and Solid Rocket Boosters (SRBs). Endeavour rolled out to Launch Pad 39A on July 27. The six-person STS-68 crew traveled to KSC to participate in the Terminal Countdown Demonstration Test on Aug. 1, essentially a dress rehearsal for the launch countdown. They returned to KSC on Aug. 15, the same day the final countdown began.
Following a smooth countdown leading to a planned 5:54 a.m. EDT launch on Aug. 18, Endeavour’s three main engines came to life 6.6 seconds before liftoff. With just 1.8 seconds until the two SRBs ignited to lift the shuttle stack off the pad, the Redundant Set Launch Sequencer (RSLS) stopped the countdown and shutdown the three main engines, two of which continued running past the T-zero mark. It marked the fifth and final launch abort of the shuttle program, and the closest one to liftoff. Bursch now had the distinction as the only person to have experienced two RSLS launch aborts, his first one occurring on STS-51 just a year earlier. Engineers traced the shutdown to higher than anticipated temperatures in a high-pressure oxygen turbopump in engine number three. The abort necessitated a rollback of Endeavour to the VAB on Aug. 24 to replace all three main engines with three engines from Atlantis on its upcoming STS-66 mission. Engineers shipped the suspect engine to NASA’s Stennis Space Center in Mississippi for extensive testing, where it worked fine and flew on STS-70 in July 1995. Meanwhile, Endeavour returned to Launch Pad 39A on Sept. 13.
Liftoff of Endeavour on the STS-68 mission.
On Sept. 30, 1994, Endeavour lifted off on time at 6:16 a.m. EDT, and eight and half minutes later delivered its crew and payloads to space. Thirty minutes later, a firing of the shuttle’s Orbiter Maneuvering System (OMS) engines placed them in a 132-mile orbit inclined 57 degrees to the equator. The astronauts opened the payload bay doors, deploying the shuttle’s radiators, and removed their bulky launch and entry suits, stowing them for the remainder of the flight.
Left: The Space Radar Laboratory-2 payload in Endeavour’s cargo bay, showing SIR-C (with the JPL logo on it), X-SAR (the long bar atop SIR-C), and MAPS (with the LaRC logo on it). Middle: The STS-68 Blue Team of Daniel W. Bursch, top, Steven L. Smith, and Thomas D. Jones in their sleep bunks. Right: Tile damage on Endeavour’s starboard Orbital Maneuvering System pod caused by a strike from a tile from Endeavour’s front window rim that came loose during the ascent.
Left: Steven L. Smith, left, and Peter J.K. “Jeff” Wisoff set up the bicycle ergometer in the shuttle’s middeck. Middle: The STS-68 Red Team of Terrence W. Wilcutt, top, Wisoff, and Michael A. Baker in their sleep bunks. Right: Wilcutt consults the flight plan for the next maneuver.
The astronauts began to convert their vehicle into a science platform, and that included breaking up into two teams to enable 24-hour-a-day operations. Baker, Wilcutt, and Wisoff made up the Red Team while Smith, Bursch, and Jones made up the Blue Team. Within five hours of liftoff, the Blue Team began their sleep period while the Red Team started their first on orbit shift by activating the SIR-C and X-SAR instruments in the payload bay and some of the middeck experiments. During inspection of the OMS pods, the astronauts noted an area of damaged tile, later attributed to an impact from a tile from the rim of Endeavour’s front window that came loose during the ascent to orbit. Engineers on the ground assessed the damage and deemed it of no concern for the shuttle’s entry.
Left: Michael A. Baker prepares to take photographs through the commander’s window. Middle: Thomas D. Jones, left, Daniel W. Bursch, and Baker hold various cameras in Endeavour’s flight deck. Right: Terrence W. Wilcutt with four cameras.
Left: Thomas D. Jones, left, and Daniel W. Bursch consult a map in an atlas developed specifically for the SRL-2 mission. Middle: Jones takes photographs through the overhead window. Right: Steven L. Smith takes photographs through the overhead window.
By sheer coincidence, the Klyuchevskaya volcano on Russia’s Kamchatka Peninsula began erupting on the day STS-68 launched. By the mission’s second day, the astronauts trained not only their cameras on the plume of ash reaching 50,000 feet high and streaming out over the Pacific Ocean but also the radar instruments. This provided unprecedented information of this amazing geologic event to scientists who could also compare these images with those collected during SRL-1 five months earlier.
Left: Eruption of Klyuchevskaya volcano on Russia’s Kamchatka Peninsula. Middle: Radar image of Klyuchevskaya volcano. Right: Comparison of radar images of Mt. Pinatubo in The Philippines taken during SRL-1 in April 1994 and SRL-2 in October 1994.
The STS-68 crew continued their Earth observations for the remainder of the 11-day flight, having received a one-day extension from Mission Control. On the mission’s eighth day, they lowered Endeavour’s orbit to 124 miles to begin a series of interferometry studies that called for extremely precise orbital maneuvering to within 30 feet of the orbits flown during SRL-1, the most precise in shuttle history to that time. These near-perfectly repeating orbits allowed the construction of three-dimensional contour images of selected sites. The astronauts repaired a failed payload high rate recorder and continued working on middeck and biomedical experiments.
Left: Steven L. Smith, left, conducts a biomedical experiment as Michael A. Baker monitors. Right: Peter J.K. “Jeff” Wisoff, left, and Smith repair a payload high rate recorder.
A selection of STS-68 crew Earth observation photographs. Left: The San Francisco Bay area. Middle left: The Niagara Falls and Buffalo area. Middle right: Riyadh, Saudi Arabia. Right: Another view of the Klyuchevskaya volcano on Russia’s Kamchatka Peninsula.
The high inclination orbit afforded the astronauts great views of the aurora australis, or southern lights.
On this mission in particular, the STS-68 astronauts spent considerable time looking out the window, their images complementing the data taken by the radar instruments. Their high inclination orbit enabled views of parts of the planet not seen during typical shuttle missions, including spectacular views of the southern lights, or aurora australis.
Two versions of the inflight STS-68 crew photo.
On flight day 11, with most of the onboard film exposed and consumables running low, the astronauts prepared for their return to Earth the following day. Baker and Wilcutt tested Endeavour’s reaction control system thrusters and aerodynamic surfaces in preparation for deorbit and descent through the atmosphere, while the rest of the crew busied themselves with shutting down experiments and stowing away unneeded equipment.
Left: Endeavour moments before touchdown at California’s Edwards Air Force Base. Middle: Michael A. Baker brings Endeavour home to close out STS-68 and a successful SRL-2 mission. Right: Baker gets a congratulatory tap on the shoulder from Terrence W. Wilcutt following wheels stop.
Left: As workers process Endeavour on the runway, Columbia atop a Shuttle Carrier Aircraft (SCA) flies overhead on its way to the Palmdale facility for refurbishment. Right: Mounted atop an SCA, Endeavour departs Edwards for the cross-country trip to NASA’s Kennedy Space Center in Florida.
On Oct. 11, the astronauts closed Endeavour’s payload bay doors, donned their launch and entry suits, and strapped themselves into their seats for entry and landing. Thick cloud cover at the KSC primary landing site forced first a two-orbit delay in their landing, then an eventual diversion to Edwards Air Force Base (AFB) in California. The crew fired Endeavour’s OMS engines to drop out of orbit. Baker piloted Endeavour to a smooth landing at Edwards, ending the 11-day 5-hour 46-minute flight. The crew had orbited the Earth 182 times. Workers at Edwards safed the vehicle and placed it atop a Shuttle Carrier Aircraft for the ferry flight back to KSC. The duo left Edwards on Oct. 19, and after stops at Biggs Army Airfield in El Paso, Texas, Dyess AFB in Abilene, Texas, and Eglin AFB in the Florida panhandle, arrived at KSC the next day. Workers there began preparing Endeavour for its next flight, STS-67, in March 1995. Meanwhile, a Gulfstream jet flew the astronauts back to Ellington Field in Houston for reunions with their families.
Diane Evans, SIR-C project scientist, summarized the scientific return from STS-68, “We’ve had a phenomenally successful mission.” The radar instrument collected 60 terabits of data, filling 67 miles of magnetic tape during the mission. In 1990s technology, that equated to a pile of floppy disks 15 miles high! In 2006, using an updated comparison, astronaut Jones equated that to a stack of CDs 65 feet high. The radar instruments completed 910 data takes of 572 targets during about 80 hours of imaging. To complement the radar data, the astronauts took nearly 14,000 photographs using 14 different cameras. To image the various targets required more than 400 maneuvers of the shuttle, requiring 22,000 keystrokes in the orbiter’s computer. The use of interferometry, requiring precision orbital tracking of the shuttle, to create three-dimensional topographic maps, marks another significant accomplishment of the mission. Scientists published more than 5,000 papers using data from the SRL missions.
Enjoy the crew narrate a video about the STS-68 mission. Read Wilcutt’s recollections of the mission in his oral history with the JSC History Office.
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By NASA
9 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The Oceans group, from the 2024 Student Airborne Research Program (SARP) West Coast cohort, poses in front of the natural sciences building at UC Irvine, during their final presentations on August 13, 2024. NASA Ames/Milan Loiacono Faculty Advisor: Dr. Henry Houskeeper, Woods Hole Oceanographic Institute
Graduate Mentor: Lori Berberian, University of California, Los Angeles
Lori Berberian, Graduate Mentor
Lori Berberian graduate student mentor for the 2024 SARP West Oceans group, provides an introduction for each of the group members and shares behind-the scenes moments from the internship.
Emory Gaddis
Leveraging High Resolution PlanetScope Imagery to Quantify oil slick Spatiotemporal Variability in the Santa Barbara Channel
Emory Gaddis, Colgate University
Located within the Santa Barbara Channel of California, Coal Oil Point is one of the world’s largest hydrocarbon seep fields. The area’s natural hydrocarbon seepage and oil production have sustained both scientific interest and commercial activity for decades. Historically, indigenous peoples in the region utilized the naturally occurring tar for waterproofing baskets, establishing early evidence of the natural presence of hydrocarbons long before modern oil extraction began. Gaseous hydrocarbons are released from the marine floor through the process of seeping, wherein a buildup of reservoir pressure relative to hydrostatic pressure causes bubbles, oily bubbles, and droplets to rise to the surface. This hydrocarbon seepage is a significant source of Methane CH4—a major greenhouse gas––emissions into the atmosphere. Current limitations of optical remote sensing of oil presence and absence in the ocean leverage geometrical as well as biogeochemical factors and include changes in observed sun glint, sea surface damping, and wind roughening due to changes in surface oil concentrations. We leverage high-resolution (3m) surface reflectance observations obtained from PlanetScope to construct a time series of oil slick surface area spanning 2017 to 2023 within the Coal Oil Point seep field. Our initial methods are based on manual annotations performed within ArcGIS-Pro. We assess potential relationships between wind speed and oil slick surface area to support a sensitivity analysis of our time series. Correcting for confounding outside factors (e.g., wind speed) that modify oil slick surface area improves determination of oil slick surface area and helps test for changes in natural seepage rates and whether anthropogenic activities, such as oil drilling, alter natural oil seepage. Future investigations into oil slick chemical properties and assessing how natural seepage impacts marine and atmospheric environments (e.g., surface oil releases methane into the atmosphere) can help to inform the science of optimizing oil extraction locations.
Rachel Emery
Investigating Airborne LiDAR Retrievals of an Emergent South African Macroalgae
Rachel Emery, The University of Oklahoma
Right now, the world is facing an unprecedented biodiversity crisis, with areas of high biodiversity at the greatest risk of species extinction. One of these biodiversity hotspots, the Western Cape Province of South Africa, features one of the world’s largest unique marine ecosystems due to the extensive growth of canopy forming kelps, such as Macrocystis and Ecklonia, which provide three-dimensional structure important for fostering biodiversity and productivity. Canopy-forming kelps face increasing threats by marine heatwaves and pollution related to climate change and local water quality perturbation. Though these ecosystems can be monitored using traditional field surveying methods, remote sensing via airborne and satellite observations support improved spatial coverage and resample rates, plus extensive historical continuity for tracking multidecadal scale changes. Passive remote sensing observations—such as those derived using observations from NASA’s Airborne Visible-Infrared Imaging Spectrometer – Next Generation (AVIRIS-NG) —provide high resolution, hyperspectral imagery of oceanic environments anticipated to help characterize community dynamics and quantify macroalga physiological change. Active remote sensing observations, e.g., Light Detection and Ranging (LiDAR), are less understood in terms of applications to marine ecosystems, but are anticipated to support novel observations of vertical structure not supported using passive aquatic remote sensing. Here we investigate the potential to observe an emergent canopy-forming macroalgae (i.e., Ecklonia, which can extend more than a decimeter above the ocean’s surface) using NASA’s Land, Vegetation, and Ice sensor (LVIS), which confers decimeter-scale vertical resolution. We validate LVIS observations using matchup observations from AVIRIS-NG imagery to test whether LiDAR remote sensing can improve monitoring of emergent kelps in key biodiversity regions such as the Western Cape.
Brayden Lipscomb
Vertical structure of the aquatic light field based on half a century of oceanographic records from the southern California Current
Brayden Lipscomb, West Virginia University
Understanding the optical properties of marine ecosystems is crucial for improving models related to oceanic productivity. Models relating satellite observations to oceanic productivity or subsurface (e.g., benthic) light availability often suffer from uncertainties in parameterizing vertical structure and deriving columnar parameters from surface observations. The most accurate models use in situ station data, minimizing assumptions such as atmospheric optical thickness or water column structure. For example, improved accuracy of satellite primary productivity models has previously been demonstrated by incorporating information on vertical structure obtained from gliders and floats. We analyze vertical profiles in photosynthetically available radiation (PAR) obtained during routine surveys of the southern California Current system by the California Cooperative Oceanic Fisheries Investigation (CalCOFI). We find that depths of 1% and 10% light availability show coherent log-linear relationships with attenuation measured near surface (i.e., within the first 10 m), despite vertical variability in water column constituent concentrations and instrumentation challenges related to sensitivity, self-shading, and ship adjacency. Our results suggest that subsurface optical properties can be more reliably parameterized from near-surface measurements than previously understood.
Dominic Bentley
Comparing SWOT and PACE Satellite Observations to Assess Modification of Phytoplankton Biomass and Assemblage by North Atlantic Ocean Eddies
Dominic Bentley, Pennsylvania State University
Upwelling is the shoaling of the nutricline, thermocline, and isopycnals due to advection by eddies of the surface ocean layer. This shoaling effect leads to an increase in the productivity of algal blooms in a given body of water. Mesoscale to deformation scale eddy circulation modulates productivity based on latitude, season, direction, and other physical factors. However, many processes governing the effects of eddies on the ocean microbial environment remain unknown due to limitations in observations linking eddy strength and direction with productivity and ocean biogeochemistry. Currently, satellites are the only ocean observing system that allows for broad spatial coverage with high resample rates, albeit with limitations due to cloud obstructions (including storms that may stimulate productivity) and to observations being limited to the near-surface. A persisting knowledge gap in oceanography stems from limitations in the spatial resolution of observations resolving submesoscale dynamics. The recent launch of the Surface Water and Ocean Topography (SWOT) mission in December of 2022 supports observations of upper-ocean circulation with increased resolution relative to legacy missions (e.g. TOPEX/Poseidon, Jason-1, OSTM/Jason-2). Meanwhile, the launch of the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite in February of 2024 is anticipated to improve knowledge of ocean microbial ecosystem dynamics. We match up SWOT observations of sea surface height (SSH) anomalies—informative parameters of eddy vorticity—with PACE observations of surface phytoplankton biomass and community composition to relate the distribution of phytoplankton biomass and assemblage structure to oceanic eddies in the North Atlantic. We observe higher concentrations of Chlorophyll a (Chla) within SSH minima indicating the stimulation of phytoplankton productivity by cyclonic features associated with upwelling-driven nutrient inputs.
Abigail Heiser
Assessing EMIT observations of harmful algae in the Salton Sea
Abigail Heiser, University of Wisconsin- Madison
In 1905, flooding from the Colorado River gave rise to what would become California’s largest lake, the Salton Sea. Today, the majority of its inflow is sourced from agricultural runoff, which is rich in fertilizers and pollutants, leading to elevated lake nutrient levels that fuel harmful algal blooms (HAB) events. Increasingly frequent HAB events pose ecological, environmental, economic, and health risks to the region by degrading water quality and introducing environmental toxins. Using NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) imaging spectrometer we apply two hyperspectral aquatic remote sensing algorithms; cyanobacteria index (CI) and scattering line height (SLH). These algorithms detect and characterize spatiotemporal variability of cyanobacteria, a key HAB taxa. Originally designed to study atmospheric mineral dust, EMIT’s data products provide novel opportunities for detailed aquatic characterizations with both high spatial and high spectral resolution. Adding aquatic capabilities for EMIT would introduce a novel and cost-effective tool for monitoring and studying the drivers and timing of HAB onset, to improve our understanding of environmental dynamics.
Emma Iacono
Reassessing multidecadal trends in Water Clarity for the central and southern California Current System
Emma Iacono, North Carolina State University
Over the past several decades, the world has witnessed a steady rise in average global temperatures, a clear indication of the escalating effects of climate change. In 1990, Andrew Bakun hypothesized that unequal warming of sea and land surface temperatures would increase pressure gradients and lead to rising rates of alongshore upwelling within Eastern Boundary Currents, including the California Current System (CCS). An anticipated increase in upwelling-favorable winds would have profound implications for the productivity of the CCS, wherein upwelled waters supply nutrient injections that sustain and fuel coastal ocean phytoplankton stocks. Increasing upwelling, therefore, is anticipated to increase the turbidity of the upper ocean, corresponding with greater phytoplankton concentrations. Historical observations of turbidity are supported by observations obtained using a Secchi Disk, i.e., an opaque white instrument lowered into the water column. Observations of Secchi depth—or the depth at which light reflected from the Secchi Disk is no longer visible from the surface—provide a quantification of light penetration into the euphotic zone. The shoaling, or shallowing, of Secchi disk depths was previously reported for inshore, transition, and offshore waters of the central and southern CCS for historical observations spanning 1969 – 2007. Here, we reassess Secchi disk depths during the subsequent period spanning 2007 to 2021 and test for more recent changes in water clarity. Additionally, we evaluate the seasonality and spatial patterns of Secchi disk trends to test for potential changes to oceanic microbial ecology. Indications of long-term trends in some of the coastal domains assessed were found. Generally, our findings suggest a reversal of the trends previously reported. In particular, increases in water clarity likely associated with a recent marine heatwave (MHW) may be responsible for recent changes in Secchi disk depth observations, illustrating the importance of MHW events for modifying the CCS microbial ecosystem.
Click here watch the Atmospheric Aerosols Group presentations.
Click here watch the Terrestrial Ecology Group presentations.
Click here watch the Whole Air Sampling (WAS) Group presentations.
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