Numerous fish, marine mammals and invertebrate species use sound in the ocean to communicate, navigate, find prey, and listen for or avoid predators. Sound in the ocean is a useful sensory modality because it can travel efficiently over long distances, and is available in deep, dark and murky waters, when light and other cues might not be. The diverse assemblage of sounds in the ocean are often referred to as the “soundscape”. Humans also produce a substantial amount of ocean noise, which can influence and change a local soundscape, and consequently could affect animal behavior.
Our soundscape research investigates spatial and temporal variability in the sounds produced by marine animals and humans in a range of marine ecosystems. Specifically, we are interested in the relationship between the sounds produced in a given habitat and the animals that live there. One of our major research questions is – do the variety and abundance of sounds recorded in a given habitat accurately reflect that habitat’s animal biodiversity? Currently, our we are carrying out research in St John, US Virgin Islands, Maui, Hawaii, and Nantucket Sound, Massachusetts. These projects are detailed below.
Coral reefs soundscapes
Coral reef soundscapes
We deployed broadband digital passive acoustic recorders developed at WHOI to assess species richness and relative animal abundance in the US Virgin Islands National Park in 2013. The goal of that project was to use short- (24 hour) and long-term (4 month) measurements to evaluate the spatial and temporal variability in the local soundscape of coral reef habitats across multiple sites. These acoustic recorders were deployed in a range of healthy and impacted coral reef sites in order to collect baseline recordings from locations with varying biological diversity. Those data were the basis of two recent publications. This approach may provide a novel means to assess both spatiotemporal heterogeneity and monitor marine ecosystem health, as well as track human activity in an area. More broadly, this investigation can help the managers and government agencies to identify changes in animal abundance and distribution, to designate key areas for protection, and to highlight areas that may be vulnerable to a changing environment.
We are currently carrying out a follow-up project on a much larger scale in Maui, Hawaii, in collaboration with Dr. Marc Lammers of the Oceanwide Science Institute. We have eight reefs instrumented with acoustic recorders and temperature loggers and have been carrying out concurrent visual surveys. The recorders are due to be retrieved in January 2016, yielding a total of 16 months of data collection.
Larval Recruitment to Coral Reefs
With new advances in underwater recording devices and acoustic data processing, this project aims to understand the relationship between coral reef soundscapes, larval settlement, and local biodiversity. While the use of sound by marine organisms has been greatly focused in marine mammals and adult fishes, larvae and other animals are also capable of detecting sound as it as it travels efficiently in the ocean. However, the role of sound in shaping larval settlement patterns and community structure is not well understood. Our work incorporates a detailed examination of coral reefs in the US Virgin Islands National Park across a gradient of habitat conditions to quantify settlement, reef conditions, and biophysical variability. Working in coral reef environments is particularly vital as they are considered, the ‘rainforests of the sea’, rich in species and marine life. Yet these reefs are under threat from a variety of stressors. Fundamentally, we are seeking to address how the underwater “soundscape” of these reefs can be used to assess the complexity of species assemblages, promote recruitment of healthy reef communities and track human (motorized) usage of these reefs. New evidence suggests that larval settlement is an active response involving orientation toward specific habitat-associated cues, and sound, which is often overlooked, plays an important role in attracting pre-settlement larvae to suitable habitat. We are also interested in the differing manners by which reefs of varying health status project their sound cues in the face of global declines of coral reef ecosystems.
Max Kaplan scuba diving over a coral reef in the Virgin Islands.
(Photo: A Mooney)
A particle motion accelerometer and acoustic listening device hang over a reef gathering soundscape data.
(Photo: A Mooney)
The first three publications from this work are listed below:
Kaplan, MB and Mooney, TA. 2016. Coral reef soundscapes may not be detectable far from the reef. Scientific Reports. 6: 31862. doi: 10.1038/srep31862
Kaplan, MK and Mooney, TA. 2015. Ambient noise and temporal patterns of boat activity in the US Virgin Islands National Park. Marine Pollution Bulletin. 98 (1-2): 221-228. doi: 10.1016/j.marpolbul.2015.06.047.
Kaplan, MB, Mooney, TA, Partan, J, and Solow, A. 2015. Coral reef species assemblages are associated with ambient soundscapes. Marine Ecology Progress Series. 533: 93-107. doi: 10.3354/meps11382.
Prior work has included developing an hand-held, diver-operated passive acoustic system to record fish sounds and associated swimming behaviors.
Mooney, TA, Lammers, MO, Santos, PA, and Nachtigall, PE. An underwater system to monitor ecologically important fish sounds: Characterization and diel trends of three species of Pomacentrids. 149th Meeting of the Acoustical Society of America. Vancouver, B.C., Canada. May 16-20, 2005.
I contributed to the development of the EAR (Ecological Acoustic Recorder), a passive acoustic monitoring device used in reef and deep sea environments.
An Ecological Acoustic Recorder (EAR) for long-term monitoring of biological and anthropogenic sounds on coral reefs and other marine habitats
Keeping track of long-term biological trends in many marine habitats is a challenging task that is exacerbated when the habitats in question are in remote locations. Monitoring the ambient sound field may be a useful way of gauging biological activity because many behavioral processes are often accompanied by sound production. This article reports the preliminary results of an effort to develop and use an Ecological Acoustic Recorder (EAR) to monitor biological activity on coral reefs and in surrounding waters for periods of up to one year. The EAR is a microprocessor-based autonomous recorder designed to periodically sample the ambient sound field and also automatically detect sounds that meet specific criteria. The system was used to record the sound field of coral reefs and other marine habitats on Oahu, Hawaii. Snapping shrimp produced the dominant acoustic energy on the reefs examined and exhibited clear diel acoustic trends. Other biological sounds recorded included those produced by fish and cetaceans, which also exhibited distinct temporal variability. Motor vessel activity could also be monitored effectively with the EAR. The results indicate that acoustic monitoring may be an effective means of tracking biological and anthropogenic activity at locations where traditional surveys are impractical.
Lammers, MO, Brainard, RE, Au, WWL, Mooney, TA, Wong, K. 2008. An ecological acoustic recorder (EAR) for long-term monitoring of biological and anthropogenic sounds on coral reefs and other marine habitats. 123(3): 1720-1228. Journal of the Acoustical Society of America.