Noise under the sea
The depths of the oceans have become noisier places as human technology has advanced, according to new research from the journal Science. This has had negative consequences for marine life.
Summarising the study for website Inside Science, Tom Metcalfe explains how, contrary to popular belief, sound carries very effectively underwater. Ocean life is often very dependent on sound, with many species of fish, as well as whales and dolphins, all using it as a vital part of their day-to-day existence.
Increased artificial noise from sources such as shipping, drilling for oil and gas, coastal construction work and blasts from dynamite fishing have all disrupted the natural soundscape of the oceans. This natural soundscape includes meadows of seagrass, forests of kelp and mangrove swamps, and is vital in helping fish swim and locate the habitats in which they raise their young. The research also suggests that excessive human noise has interfered with mating calls, leading to concerns about long-term damage to fish population levels.
However, the authors are optimistic about solutions to the problem. Technology already exists to make activities such as underwater surveys more animal-friendly, and other policy solutions are available, such as speed limits for ships. Furthermore, unlike climate change or oil spills, the effects of sound pollution under the sea will decline swiftly once the causes are removed. Doug Nowacek, professor of marine conservation technology at Duke University, states:
One of the beauties of noise is that when you stop making it, it goes away. Unlike chemicals in the groundwater, or pollutants in the air, the minute you turn off the source… within a few minutes, it’s gotten quieter.
Read the full article: Tom Metcalfe, ‘Human-made noise in the oceans is a growing problem’, Inside Science, 8 February 2021
Decision making and anxiety
People suffering from anxiety or depression have often reported difficulty making decisions and dealing with uncertainty. Writing for the British Psychological Society, Emily Reynolds reports on new research confirming that people with higher levels of anxiety and depression are less able to adapt to fast-changing situations.
The study, carried out by staff at the University of California, Berkeley, the University of Tübingen and the University of Oxford, builds on existing research on intolerance of uncertainty being a core feature of generalised anxiety disorder. While many studies have relied on patients’ self-reported behaviour, this study instead focuses on the cognitive processes involved in choice making under uncertain conditions.
Participants were between 18 and 55 and suffering from generalised anxiety disorder or major depressive disorder. The comparator group had no history of mental illness. The study presented participants with a video game in which they were asked to choose between two shapes. One shape resulted in a small monetary reward, while the other delivered an electric shock. The game had two settings—one more stable, with the reward shape consistently administered 75% of the time, and one volatile, where the reward shape changed regularly and in an unpredictable way. Participants with diagnoses of anxiety or depression were slower to adjust their responses to the changes in probabilities. The authors suggest this is down to anxious or depressed people being more likely to fixate on what they did wrong, rather than remembering a time they achieved a positive outcome.
The authors of the study go on to argue that those suffering anxiety or depression can improve their judgement if they focus on what they got right in the past, instead of what they get wrong, a technique often taught as part of cognitive behavioural therapy.
Read the full article: Emily Reynolds, ‘In times of anxiety and low mood, focusing on past successes could improve decision–making’, British Psychological Society, 9 February 2021