Monterey Bay Aquarium Research Institute
2009 Pacific Northwest Expedition


Leg 5 Logbook - Submarine Volcanism II
Day 4 — Highs and lows of scenery
September 1, 2009

Latitude 45 degrees 56.27 minutes N
Longitude 129 degrees 59.24 minutes W

Today's dive had highs and lows of scenery. It began with highs: on the north end of the 1998 lava flow and onto the much larger and older Magnesia flow. The channels of both flows are floored with superhighways of lineated and jumbled sheet flows. To the sides of the channels are tall lava pillars and lobate-pillow roofed caverns of inflated lava lakes that formed early in the eruptions and drained as the eruptions continued and waned. We climbed onto the flank of the volcano and encountered the lows of scenery (in my opinion): vast plains of sediment. The few rocks that protruded were so similar in appearance that it was difficult to tell where boundaries between lava flows were. At the end of the dive we ascended a flattened, fractured cone of lava pillows with the highest elevation on the eastern rim. We collected a push-core horizontally into an exposure of layered sediment at its base that at last gave us an opportunity to collect the volcanic fragments that erupted during or soon after the caldera collapsed, one of the primary—and unattained—goals of Leg 4 of the expedition. The weather has been sunny and calm but that is predicted to change.

—Jenny Paduan

The highs: lava pillars support the crust remaining when the lava lake drained and the roof collapsed. The horizontal bands mark surface levels as the lake dropped.

The lows: sediment nearly buries bulbous pillow lavas on the southeast flank of Axial.

One of the geology goals of our dive today to the southeast rim of Axial Seamount was to collect older lava flows and the base layer of the overlying sediment. We collected several lava-sediment pairs and groundtruthed individual lava flow boundaries we recently mapped using newly-acquired MBARI AUV data. Back on shore, we will date these lava flows using the decay rate for several rare isotopes. Dating the carbon of foraminifera found in the basal layers of sediment overlying the lava flows offers another way to place a minimum age on these eruptions. These are facets of a larger multidisciplinary project undertaken with colleagues that aims to date recent eruptions near mid-ocean ridges. Specifically, at Axial Seamount dating individual lava flows will assist in defining spatial and temporal variations in volcanic output and constraining the age and style of the caldera formation. Our working hypothesis is that Axial Seamount previously had a rounded or cone-shaped peak prior to the formation of its roughly 8 x 3 x 0.1 kilometer caldera we see today. We are interested in determining whether the formation of the caldera occurred catastrophically (a singular event) or over an extended period of time through sequential subsidence events.

—Brian Dreyer

A crab perches on a short lava pillar, which is dusted with hydrothermal sediment from vents that used to be active in the vicinity.

Eddies in a fast-moving ropy sheet flow made these lava whorls.

Today’s dive on Axial seamount yielded, by far, some of the most amazing and spectacular views of lava-flow morphology that I have ever seen: gigantic lava tubes with roofs collapsed inward to make cave-like structures, at times many meters across; free-standing pillars of lava that once supported hardened pillow lava flows above them, and pillars still supporting such roofs; and narrow, natural bridges of lava crust between them, reminiscent of gothic cathedrals in their dark, glassy splendor. Collapsed flows showed the multi-layer cake (in cross section) of lava underneath the pillowy crust and in places elephantine trunks drooping off ledges into the dark caves below. We also traversed hundreds of meters of heavily sedimented bottom with only occasional cranial pillows of lava poking their heads above the deep silt. Some of what we saw reminded me of terrestrial versions, seen while camping during my childhood at places in northeastern California and throughout the southern Sierras. Seeing such structures, highly reminiscent of “Captain Jack’s Stronghold,” but at depths exceeding 1,500 meters, was mind-boggling to say the least.

We have conducted a number of biological transects on our dives and encountered several interesting animals, including brittle stars which I have learned can REALLY move when they need to, propelling themselves forward with their arms or even rotating in a spinning fashion as if they were attached to a swivel! Yesterday and today we managed to collect a variety of organisms including crinoids with and without stalks, starfish, sea cucumbers, sponges, and an amphipod of apparent morphological similarity to those we see at our whale-fall sites in the Monterey Bay. Also noted in yesterday’s catch were several benthic copepods (possibly harpacticoida) collected from over 2,400 meters depth—the best evidence I’ve seen so far for including copepod probes in our efforts to detect micro-invertebrates and their larvae using the Deep ESP set for deployment by MBARI later this year.

—Julio Harvey

Sponges densely populate only this one small area of the huge lava flows we traversed today. They were speckled with bacterial mat, suggesting that diffuse, low-temperature hydrothermal fluids were flowing here.

An urchin calls this bare lava rock home.

Yesterday we were able to observe one sea star that underlies the importance of submersibles to our understanding of marine animals. From our control room, we were able to observe via the Doc Ricketts the giant deep-sea “slime star” Hymenaster. Hymenaster has been well known to scientists having been collected by the HMS Challenger expedition in the 19th century, but specimens have almost never been observed alive and preserved specimens are usually badly damaged from trawl nets or simply not preserved very well. Often, a preserved specimen looks like messy leftovers from an extraterrestrial’s dinner plate!

With the high resolution video on the ROV we were able to observe these animals in their natural habitat. In the wild, the animal’s body is supported almost entirely by water pressure and the body has thorn-like projections that are not seen in a preserved specimen. Adult Hymenaster are large animals, sometimes almost half a meter in diameter and have a beautiful red-purple color. The body wall is gelatinous and includes a bizarre skeleton that is quite different from more conventional sea stars. The surface of these animals is made up of a transparent tent-like membrane which covers over the surface of the starfish itself. This membrane opens up on the top which permits some species of Hymenaster to produce a defensive stream of mucus!! Probably as a defense mechanism against predators. These stars often produce so MUCH mucus that one star can fill a collection container in a matter of minutes!

When we have observations of these animals in the natural habitat we can begin to infer other important questions that are important to deep-sea ecology. What does it eat? How does this affect other deep-sea animals? What ecological role do they occupy? How did these sea stars acquire these unique adaptations to living in the deep-sea? Seeing them alive is an important first step towards understanding these questions.

—Chris Mah

A Hymenaster sea star at CoAxial yesterday. This star was a third of a meter across.

Chris holding two specimens of stars collected yesterday.

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Leg 5
 Equipment

R/V Western Flyer

The R/V Western Flyer is a small water-plane area twin hull (SWATH) oceanographic research vessel measuring 35.6 meters long and 16.2 meters wide. It was designed and constructed for MBARI to serve as the support vessel for ROV operations. Her missions include the Monterey Bay as well as extended cruises to Hawaii, Gulf of California and the Pacific Northwest.

ROV Doc Ricketts

ROV Doc Ricketts is MBARI's next generation ROV. The system breaks new ground in providing an integrated unmanned submersible research platform, with many powerful features providing efficient, reliable and precise sampling and data collection in a wide range of missions.

R/V Zephyr

R/V Zephyr is the primary support vessel for MBARI's autonomous underwater vehicle (AUV) program. This 26-meter vessel is also used to maintain environmental moorings, collect time-series data along the California Current, and support scuba divers as they study near-shore habitats.

AUV D. Allan B.

The MBARI Mapping AUV is a torpedo-shaped vehicle equipped with four mapping sonars that operate simultaneously during a mission. The multibeam sonar produces high-resolution bathymetry (analogous to topography on land), the sidescan sonars produce imagery based on the intensity of the sound energy's reflections, and the subbottom profiler penetrates sediments on the seafloor, allowing the detection of layers within the sediments, faults, and depth to the basement rock.

Push cores

A push-core looks like a clear plastic tube with a rubber handle on one end. Just as its name implies, the push core is pushed down into loose sediment using ROV Tiburon's manipulator arm. As the sediment fills up the core, water exits out the top through one-way valves. When the core is pulled up again, these valves close, which (most of the time) keeps the sediment from sliding out of the core tube. When we bring these cores back to the surface, we typically look for living animals and organic material in the sediments.

Niskin bottles

Niskin bottles are used to collect water samples as well as the tiny bacteria and plankton in that volume. The caps at both ends are open until the bottles are tripped, when the caps snap closed.


Biobox

The box fits in a partition in the sample drawer. It is shown open, with an animal being placed into it by the ROV's manipulator. When the lid is closed, the box will hold water to protect the animals inside.


Rock crusher

This device is used to collect volcanic glass fragments from the surface of a flow. It is made of about 450kg of lead and steel and is launched over the stern of the ship on a wire. Fragments of rock that break off of the lava flow on impact are trapped in wax-tipped cones mounted around the crusher. The wax is melted in the lab to liberate the rock particles for analysis.

Benthic toolsled/
Manipulator arm/
Sample drawer with partitions

The benthic toolsled is attached to the bottom of the ROV for our geology dives. Its components are the manipulator arm and the sample drawer. The sample drawer is shown open on deck, full of rocks. Normally it is closed when the vehicle is operating and is opened only when a sample needs to be stowed. Partitions in the drawer help us keep the rocks in order. The rocks often look alike, but the conditions and chemistries of the eruptions are different so it is important that we know where each came from.

Glass suction sampler

This equipment is used to vacuum glass particles and larval animals from cracks and crevices. The carousel of small plastic jars fitted with wire mesh will be mounted in the benthic toolsled. The hose will be held by the ROV's manipulator and a suction will be drawn by the pump.

Sediment scoops

Canvas bags on a T-handle for collecting gravel or other materials that fall out of a push-core.


Temperature probe

Held by the ROV's manipulator, the wire on the right is placed into the fluid emitted from a hydrothermal vent to record the temperature.


 Research Team

David Clague
Senior Scientist, MBARI

Dave's research interests are nearly all related to the formation and degradation of oceanic volcanoes, particularly Hawaiian volcanoes, mid-ocean ridges, and isolated seamounts. Topics of interest include: compositions of mantle sources for basaltic magmas and conditions of melting; volatile and rare-gas components in basaltic magmas and their degassing history; chronostratigraphic studies of eruption sequence and evolution of lava chemistry during volcano growth; subsidence of ocean volcanoes and its related crustal flexure, plate deformation, and magmatic activity; geologic setting of hydrothermal activity; origin of isolated seamounts; and monitoring of magmatic, tectonic, and hydrothermal activity at submarine and subaerial volcanoes.

Jenny Paduan
Senior Research Technician, MBARI

Jenny works with Dave Clague in the Submarine Volcanism project. On this expedition, Jenny will be in charge of the GIS work, including use of the recently acquired, high-resolution MBARI Mapping AUV data of our dive sites. She will also stand watches in the ROV control room, help with rock and sediment sample workup and curation once the vehicle is on deck, and coordinate these cruise logs for our group's two legs of the expedition. She is now quite solidly a marine geologist, but her degrees are in biochemistry (Smith College) and biological oceanography (Oregon State University). She is thankful for the opportunities that have led her to study volcanoes, and loves being involved with the research and going to sea. She looks forward to discovering more about how the Earth works.

Brian Dreyer
Science Postdoctoral Fellow, MBARI

Brian completed his Ph.D. in igneous geochemistry at Washington University in Saint Louis in 2007 and has since been working in MBARI's Submarine Volcanism Group. Brian applies the principles of isotope geochemistry to young samples of volcanic rocks to gain insight into aspects of magmatism. Much of his postdoctoral work focuses on eruption and petrogenetic timescales of Axial Seamount, the most volcanically active portion of the Juan de Fuca Ridge. His other research interests include geochemistry of the Earth's mantle, magmatic interaction between oceanic spreading centers and hotspots, and exploiting the systematics of rare isotope species to quantify material flux through subduction zones.

Craig McClain
Assistant Director of Science, National Evolutionary Synthesis Center

Craig has conducted deep-sea research for 11 years and published over 30 papers in the area. Participation in dozens of expeditions has taken him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig's research focuses on the ecological and evolutionary drivers of marine invertebrate biodiversity and body size. He is the author and editor of Deep-Sea News, a popular deep-sea themed blog and rated as the number one ocean blog on the web, and his popular writing has been featured in Cosmos, Science Illustrated, and Open Lab: The Best Science Writing on the Web.


Linda Kuhnz
Senior Research Technician, MBARI

Linda specializes in the ecology of small animals that live in marine sediments (macrofauna), and larger invertebrates and fishes that live on the seafloor or just above it (megafauna). She conducts habitat characterization studies in benthic (seafloor) ecosystems using underwater video and by collecting deep-sea animals. She hopes to find some new and interesting animals in the unique habitats we are visiting on this cruise.

Ángel Puga-Bernabéu
Postdoctoral Fellow, University of Sydney

Angel is a carbonate sedimentologist specialist in non-tropical carbonate sediments. His current research, however, is focused on the tropical realm. He is working on drowned reefs from Hawaii, studying their morphology and structure, sedimentary facies and stratigraphical successions in order to attempt to constraint eustatic sea-level changes, subsidence rates, drowning times, carbonate accretion rates, and paleobathymetry. In this expedition Angel hopes to learn basic skills in marine geology that could help him to better understand the data he works with in his current research.

Julio Harvey
Research Technician, MBARI

Julio is a molecular ecologist and evolutionary biologist currently working on the population genetics of various deep-sea invertebrate species in Bob Vrijenhoek's laboratory. Julio is also developing molecular probes capable of detecting a variety of marine invertebrate larvae and other microorganisms from environmental seawater samples as part of the Environmental Sample Processor project.

Chris Mah
Research Collaborator, Smithsonian Institution

Chris specializes in the evolution, systematics, and taxonomy of echinoderms, specifically asteroids (starfish or sea stars). His research emphasizes cold-water species, including those living in the deep sea and at high-latitudes (Antarctica and the Arctic). He has identified starfish species for National Geographic, the National Marine Fisheries Service, and MBARI, as well as organizations in France, Australia, Palau, and New Zealand. He has been on many deep-sea cruises, including submersible work in the Bahamas and Hawaii as well as more conventional scientific cruises in Antarctica, Alaska, as well as off Monterey, California. He is also the author of the Echinoblog, an echinoderm-themed blog. This will be his first trip on the Western Flyer.

Soureya Becker
Graduate Student

Soureya recently received her bachelor's degree in general geology in Munich. She gained field experience related to volcanology during a campaign to Colima volcano in Mexico, where she looked at pyroclastic flow and block-and-ash flow deposits, did detailed stratigraphic logs, and performed density measurements in the field. She also participated in a field trip to Etna, Vulcano, Lipari, and Stromboli volcanoes where she was shown the different aspects of Italian volcanism. After these terrestrial experiences she is now looking forward to discovering more about submarine volcanism. She will benefit greatly from participating in this cruise, as it is highly complementary to her university education.

Levin Castillo
Student, University of Quebec, Chicoutimi

Levin Castillo-Guimond finished a BSc-Honour's degree in Earth Sciences at University of Quebec in Chicoutimi (UQAC-2009). His prime interest was on the physical volcanology of Archean mafic and felsic submarine successions, as they are often associated with volcanic massive sulfide deposits (VMS). In addition, to better understand large-scale caldera evolution and pyroclastic processes, Levin participated on a field trip in autumn 2007 on the island of Tenerife (Canary Islands). In summer 2009 he worked for an exploration focusing on gold and uranium deposits.

Gillian Clague

Gillian recently received her BSc-Honours degree in Marine Biology in Brisbane, Australia. She gained diving field experience while observing fish behavior on the Great Barrier Reef. On previous research cruises, she has assisted in the processing of collected organisms and in the collection and analysis of underwater video to identify the benthic life present on flows over an age series. On this cruise, she will assist in the collection of underwater video and hydrothermal clams and tubeworms, and aims to gain a better understanding of the diversity of animals living at these sites.