explorations now: What do you do for a living?
Simone Baumann-Pickering: I study the ecology of large marine predators, particularly marine mammals. I try to understand their presence using acoustic methods in space and time, mostly in the Northern Hemisphere, and how the environment influences their presence. The environment is changing with time and so animal behaviors are changing as well. You can look at daily patterns, lunar patterns and also seasonal patterns and this is the natural cycle, but then you have stressors influencing these behaviors. Stressors like climate change that impact the whole ecosystem or noise that is being emitted into the ocean by people.
I'm particularly interested in how deep-ocean conditions are changing, how deep-diving whales are accessing resources and how these resources are changing with underlying conditions. We have long-term data sets where we can tie together how different water masses bring certain animal communities to a site. Based on the prey communities that are present you will see the top predators changing. We've been trying to figure out for a long time now, for example, why some of the deep divers such as beaked whales seem to leave seasonally in Southern California for no obvious reason. It may be that a warm and low salinity water mass in the deep ocean takes away their preferred prey and so that's when they leave.
The difficulty is disentangling natural behavior from human-induced behavior or changes in behavior. We're trying to model those kinds of relationships, quantifying them so that we can predict how the future may look like for some of the marine mammals. The goal is to provide a scientific basis for management decisions to conserve these protected species.
en: What are some of the main questions in your field?
SBP: The thing that really excites me about the acoustic work is how we can broadly view the biology of a system. Imagine you're in the center of a city. You have cars honking, cars driving by. There's this certain noise field. Now imagine yourself walking along the beach. You have waves that you can hear, maybe a sea bird squawking that's flying by. Then imagine you're going into a forest and that is going to sound entirely different yet again. Similar scenarios can be found in the ocean where there are all these different habitats from kelp forest to mud flats to deep ocean. Every one of these habitats is home for a different set of species and different sounds could be heard depending on where you are and who's living there. In all of these areas of the ocean, we are hearing people intruding more and more in these soundscapes and quantifying and understanding that is a big driver for me.
The major questions in the field would be how will climate change influence marine ecosystems as a whole and what will this do to marine protected species such as marine mammals? How do additional stressors such as chronic noise impact populations that are already under pressure? And underlying this whole effort is that we're still trying to figure out how can we expand our knowledge on which species is making which sound.
en: What are some of the tools you use?
SBP: For the most part, I'm using long-term autonomous acoustic recording packages that are deployed in the ocean for months at a time. They have weight at the bottom that keeps them down at the seafloor and they sit at 1,000 meters (3,300 feet) depth or more. They record all the sounds from low-frequency ship sounds or baleen whale sounds to very high-frequency echolocation clicks of dolphins. But they also record wind and waves and earthquakes and any other kind of noises that the earth may make as well as sounds from humans. We retrieve the instrument by sending an acoustic signal, which brings it to the surface to be picked up by the ship.
As the instruments record for months in the ocean, they collect multiple terabytes of data on hard drives. We take those out of the instrument when we bring it into our computing facility. We run automated detectors to search for certain signals of interest. We also do this with data that we have in our archive to inspect different geographic areas, time periods and species.
We now have almost three petabytes of acoustic data collected since roughly 2006. Over the past decade, we've collected acoustic data continuously at several sites in the Northern Hemisphere and also in the polar regions.
Lastly, we're using statistical tools to understand relationships in our data. For the question of who's making what sound, usually you want to have a connection between an image or a visual observation with the acoustic sound that you collect. And so often there is boat-based work where you have observers on the ships and you tow a hydrophone behind the boat to make those observations.
One project that I'm working on right now is to understand human noise in marine sanctuaries. Our multi-institutional team has acoustic recorders in many of the sanctuaries on the East Coast, West Coast, and the Hawaiian Islands. We're looking at the human noise footprint and what that may mean for the animals in these habitats.
We’re looking at large ships coming by, but we're also seeing quite a high density of pleasure craft and sport fishing boats. We're seeing explosives used by fishermen in Southern California, particularly around the Channel Islands National Marine Sanctuary and the Monterey Bay Sanctuary. On the East Coast, we're seeing seismic activity from survey ships. All of those sources are going to be audible to any animal that has any sort of pressure sensor and there have been negative impacts documented for many marine species from mollusc and fish larvae all the way to marine mammals.
We observe how ocean conditions are changing geographic distributions of prey. And so the predator is going to follow. Sometimes that leads them to overlap with human activities. As soon as they're becoming more coastal or they get into areas where fishing activity is high or the shipping industry is active, then conflicts occur and those are not necessarily predictable. By understanding those predator-prey relationships, we may be able to advance our predictions and manage those conflicts.
en: Why did you come to Scripps?
SBP: I came to Scripps as a visiting graduate student. I had heard of Scripps from the faculty at the University of Tübingen (Germany) where I was a grad student and was in absolute awe. And so I thought this is the place to learn and study. I quickly realized that the network of excellent researchers available here is conducive to some exciting research, so I stayed on as a postdoc and then got hired into a faculty position.
– Robert Monroe