Hurricanes Irma and Maria temporarily altered the choirs of land and sea animals – sciencedaily


Audio recordings of Hurricanes Irma and Maria passed over Puerto Rico show how the cries of coastal creatures changed in response to the deadly storms. The hurricanes caused a major disruption in the acoustic activity of the cracking shrimp, a reduction in insect and bird noises, and potentially an intensification of fish choirs, according to new research presented at the Ocean Science meeting on Friday.

In March 2017, researchers set up acoustic monitoring sites in the coastal forests and coral reefs of the southwest coast of Puerto Rico to continuously record the ambient sounds of the region. Their goal was to capture the region’s land and sea soundscapes – particularly the cacophony of sounds created by animal vocalizations – and document how and why they change over time.

But the passage of Hurricanes Irma and Maria over Puerto Rico in September gave researchers unexpected insight into how coastal soundscapes change in response to natural disasters. Although the hurricanes did not directly affect the study area, audio recordings reveal that the storms had noticeable short-term effects on fish choirs, shrimp activity in coral reefs, and sea calls. birds and insects on earth.

Records show that the fish increased the intensity of their nocturnal choirs in the days following Hurricane Irma. The snapping of snapping shrimp, which is among the loudest animal sounds in the ocean, dropped during Hurricane Maria, and the daily rhythm of the snapping was disrupted for several days.

In the nearby dry forests, Maria had more lasting effects on the soundscape. There was a marked reduction in insect noises in the three weeks following the storm. Listen to time-lapse recordings of changing insect sounds, fish choirs, and snapping shrimp activities here.

The results show how scientists can use the soundscape as a measure of biodiversity and environmental change, the researchers say. Capturing responses from a variety of species at the same time can help scientists better understand how the ecosystem is affected as a whole, according to Ben Gottesman, a doctoral student at Purdue University in West Lafayette, Indiana, and senior author of the new research.

“Sometimes you can’t visually assess an impact, but you can certainly capture it by altering the soundscape,” said Felix Martinez, ecologist and program manager at the NOAA National Centers for Coastal Ocean Science in Ann Arbor, Michigan. , who showcase the new findings on Friday at the 2018 Ocean Sciences Meeting, co-sponsored by the Association for the Sciences of Limnology and Oceanography, The Oceanography Society and the American Geophysical Union. “We really need to understand when these changes are natural versus some kind of stressor, whether human or natural.”

Similar to birds and frogs, fish call to find mates and defend spawning grounds, producing choirs at specific times of the day and year. Gottesman suspects that one of the reasons the fish may have singed more after Hurricane Irma – which coincided with the full moon – was that the water became very cloudy, making them harder for people to see. predators.

While fish increased their activity after Hurricane Irma, shrimp catches declined sharply during Maria and rebounded in the first days after the storm. Slamming shrimp make a loud cracking noise with their claws to stun and grab their prey. The brittle shrimp recorded in Puerto Rico had a very precise timeline of when they broke the most, almost like clockwork, Gottesman said. After the storms, the peaks of cracking activity at dawn and dusk were less pronounced and it took several days for them to return to pre-storm levels.

Researchers suspect that the shrimp might have cracked less for several reasons. During storms, the intense current and turbidity likely deterred the shrimp from seeking prey, or the extreme turbidity muffled the high frequency shrimp snapping. After the storm, Maria may have disturbed their rocky coral habitats, the shrimp may have spent time cleaning their burrows, or they may not have been able to see their prey when the water turned cloudy.

Post-storm recordings show that the vocalizations of land and sea animals in that part of Puerto Rico, which was not in the eye of the storm, eventually rebounded to pre-storm levels. Maria was a catastrophic disaster, causing damage estimated at $ 90 billion, but the new findings show how well this coastal ecosystem has weathered the storm, researchers say.

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