Month: March 2017

Beyond the Rock: Using Satellite Trackers to Study the Lives of Common Murres

By Stephanie Loredo, Seabird Oceanography Lab, OSU

Photo credit: Seabird Oceanography Lab

Common murres (Uria aalgee) are the most abundant seabird on the Oregon Coast. At least half of the population in the California Current Ecosystem breeds on the Oregon Coast (half a million seabirds). This makes them ecologically important consumers of forage fish, especially during the breeding season when they use state-waters.

While they spend most of their time at sea, murres must come to shore to breed. During this time, they are highly visible by humans as they breed in large masses on rocky islands. While they are not the most agile on land, due to their short and stubby legs, they are actually amazing divers. Their short flipper-like wings help them swim, and they typically reach depths of 30-60m to catch their prey.

Aside from their underwater aviation skills, they make great parents as well. Both parents will incubate and care for their chick – murres only lay one egg a year – until they fledge; once they leave the rock, male murres take full responsibility for their chicks while the moms go on vacation (they worked hard to lay the egg so they need some time to recuperate). After the breeding season, murres leave the rock in large quantities – this is often the last time humans will see them this year in large aggregations from shore.

Despite their omnipresence and importance as a marine predator in Oregon, there is still a lot we don’t know about murres. Where do murres go when they are not breeding? Do they migrate? Where do they feed during the breeding and non-breeding period? What habitat characteristics are associated with feeding areas? By answering these questions, we increase knowledge of murre ecology in Oregon. Moreover, a more comprehensive understanding of the year-round movements of murres aids marine spatial planners take more informed actions on the current decisions regarding offshore renewable energy development. This is what I hope to achieve through my Masters research project at OSU.

Most of what is known about the offshore distribution of murres in Oregon comes from vessel observations. However, vessel data only provide snapshots in time, and not a continuous picture of area-use. Within the Seabird Oceanography Lab (SOL), we are using individual satellite tracking devices to follow the movements of murres associated with the Yaquina Head colony, which is a prominent breeding colony in Oregon located near Newport.

A common murre displaying a satellite tag prior to release.

SOL was able to track 15 common murres associated with the Yaquina Head colony in 2015 and 2016.  These tags were deployed periodically throughout the breeding period and have been successful in tracking birds for up to three months. Thus far, we have tracking data ranging from May to December (only one bird tracked during December).

Tracking data from 2015 and 2016 of murres off the Yaquina Head colony provide an interesting comparison.  In both years, murres experienced warmer ocean conditions, high Bald eagle disturbance rates, and consequently high Western gull egg predation at the colony. Some data also indicate low prey availability.  The combination of all these factors is most likely the reason for the observed reproductive failure at the colony in both years. Tracking data showed that 13 of the 15 birds tagged dispersed from the colony earlier than expected. The maps below summarize the dispersal of birds by year and by time of deployment.

 

Each map (Left: 2015, Right: 2016) illustrates all birds that dispersed from the colony and did not engage in central-place foraging (feeding trips to and from the colony). Sample size: n2015=7, n2016_spring=1, n2016_summer=3.

Most birds made a northward movement and traveled as far north as British Columbia, Canada.  Along their movement north, they used inlets and bays, but one of the most prominent areas used was the Columbia River plume. Birds used the Columbia River mouth area during the summer and fall, with the most time spent there during the summer. Dispersal from the colony was not what we expected; we expected individuals to breed on colony and engage in central-place foraging  (feeding to and from the breeding site) nearshore until mid-August when they usually leave the rock. However, we are still interested in the habitat characteristics of feeding areas and the conditions that led to movement from one feeding area to the next.

Prior to examining habitat associations of murre feeding areas, we must first determine their behavior state at each point location derived from the satellite tags.  After data cleaning and filtering out erroneous locations, we applied a behavioral analysis (Residence in Space and Time method) to determine behaviors associated with each point location. This analysis has allowed us to distinguish between intensive foraging, transiting, and extensive foraging. Extensive foraging locations can be interpreted as a set of locations that are mostly spread out in space, where murres searched for prey. On the other hand, intensive foraging locations can be interpreted as a set of locations that are very close together in space where murres likely found prey, and thus spent more time.

We are finalizing the extraction of environmental data for each point location from satellite data. Once all data are extracted, we can begin analysis for determining what environmental conditions were sought during dispersal and what types of habitats are preferred. Some of the ocean conditions that will be examined are sea surface temperate, wind, upwelling index, and primary net productivity. Some other habitat descriptors we are interested in assessing are substrate, distance to river mouth, salinity, depth, distance to the 200-m isobath, and distance to shore. For now, exploration of data indicates differences in habitat associations by behavior and between seasons.

Sample size means everything in a study like this so I am happy to say that more data is yet to come: SOL plans to deploy 15 more tags during spring and summer of 2017. I am excited to see what the additional tagged murres will do, and whether they will follow a pattern similar to those tracked in 2015 and 2016. However this time around, we will deploy tags as late in the summer/early fall as we can, in hope of acquiring some novel winter data to fill this knowledge gap. If we are successful, we may finally have a better idea of what life is like for common murres during more of the year beyond the rock.

 

Celebrating Hydrothermal Vents!

By Florence Sullivan, MSc Student OSU

40 years ago, in 1977 OSU researchers led an NSF funded expedition to the Galapagos on a hunt for suspected hydrothermal vents. From the 1960s to the mid-1970s, mounting evidence such as (1) temperature anomalies found deep in the water column, (2) conduction heat flow probes at mid ocean ridges recording temperatures much lower than expected, (3) unusual mounds found on benthic mapping surveys, and (4) frequent, small, localized earthquakes at mid oceanic ridges, had the oceanographic community suspecting the existence of deep sea hydrothermal vents. However, until the 1977 cruise, no one had conclusive evidence that they existed.  During the discovery cruise at the Galapagos rift, the PI (principle investigator), Dr. Jack Corliss from OSU, used tow-yos (a technique where you drag a CTD up and down through the water in a zig zag pattern – see gif) to pinpoint the location of the hydrothermal vent plume. The team then sent the Deep Submergence Vehicle (DSV) Alvin to investigate and returned with the first photographs and samples from a hydrothermal vent. While discovery of the vent systems helped answer many questions about chemical and heat fluxes in the deep sea, it generated so many new questions that novel fields of study were created in biology, microbiology, marine chemistry, marine geology, planetary science, astrobiology and the study of the origin of life.

 “Literally every organism that came up was something that was unknown to science up until that time. It made it terribly exciting. Anything that came [up] on that basket was a new discovery,” – Dr. Richard Lutz (Rutgers University)

In celebration of this great discovery, OSU’s College of Earth, Ocean and Atmospheric Sciences sponsored a seminar looking at the past, present, and future of hydrothermal vent sciences. Dr. Robert Collier began with a timeline of how the search for hydrothermal vents began, and a commemoration of all the excellent researchers and collaborations between institutions and agencies that made the discovery possible. He acknowledged that such collaborations are often somewhat tense in terms of who gets credit for which discovery, and that while Oregon State University was the lead of the project, it takes a team to get the work done.  Dr. Jack Corliss proudly followed up with a wonderful rambling explanation of how vent systems work, and a brief dip into his ground breaking paper, “An Hypothesis concerning the relationship between submarine hot springs and the origin of life on Earth.” Published in 1981, with co-authors Dr. John Baross and Dr. Sarah Hoffman, they postulate that the temperature and chemical gradients seen at hydrothermal vents provide pathways for the synthesis of chemical compounds, formation and evolution of ‘precells’ and eventually, the evolution of free living organisms.

Dr. Corliss, Dr. Baross, and Dr. Hoffman were the first to suggest the now popular theory of the origin of life at hydrothermal vents. (click on image to read full paper)

Because of time constraints, the podium was swiftly handed over to Dr. Bill Chadwick (NOAA PMEL/ HMSC CIMRS) who brought us forward to the present day with an exciting overview of current vent research.  He began by saying “at the beginning, we thought, ‘No one has seen one of these systems before, they must be very rare…’ Now, we have found them [hydrothermal vents] in every ocean basin – including the arctic and southern oceans. We just needed to know how to look!”  Dr. Chadwick also reminded us that even 40 years later, new discoveries are still being made. For example, on his most recent cruise aboard the R/V Falkor in December 2016, they found a sulfur chimney that was alternately releasing bubbles of gas (sulfur, CO2 or other, hard to know without sampling) or bubbles of liquid sulfur! Check out the video below:

Some of the goals for this recent cruise included mapping new areas of the Mariana back-arc, and investigating differences in the biological communities between vents in the Mariana trench region (a subduction zone) and vents in the back arc (a spreading zone) to see if geology plays a role in biological community composition.  For some very cool video footage of the expedition and the various dives performed by the brand new ROV SUBastian (because all scientists love puns), check out the Schmidt Ocean Institute youtube channel.

Dr. Chadwick showed this video to highlight results from his last cruise.

Finally, Dr. Andrew Thurber wrapped up the session with some thoughts about hydrothermal vents from the perspective of an ecosystem services model. Even after 40 years of research, there are still many unknowns about these ecosystems.  Individual vent systems are inherently unique due to their deep sea isolation. However, most explored sites have revealed metals and mineral deposits that have generated a lot of interest from commercial sea floor mining companies. Exploitation of these deposits would be an example of ecosystem “provisioning services” (products that are obtained from the ecosystem). Other examples include the biology of the vents as a source of new genetic material, and the thermal and chemical gradients as natural laboratories that could lead to breakthroughs in pharmaceutical research. Cultural services are those non-material benefits that people obtain from an ecosystem. At hydrothermal vents these include new scientific discoveries, educational uses (British children’s television show “The Octonauts,” has several episodes featuring hydrothermal vent creatures), and creative inspiration for artists and others. Dr. Thurber cautions that there are ethical questions to be answered before considering exploitation of these resources, but there is a lot of potential for commercial and non-commercial use of vent ecosystems.

Vent inspired art by Lily Simonson

As an undergraduate at the University of Washington, I spent time as a research assistant in Dr. John Baross’ astrobiology lab. We studied evolutionary pathways of hydrothermal vent viruses and bacteria to inform the search for life on exoplanets such as Jupiter’s moon Europa.  It was very fun and exciting for me to attend this seminar, hear stories from pioneers in the field, and remember the systems I worked on in undergrad.  I may have moved up the food chain a little now, but as we all work on our pieces of the puzzle, it is important for scientists to remember the interdisciplinary nature of our work, and how there is always something more to learn.