State of the Oceans — Log 85

May 28

YOUR WEEKLY BRIEFING FROM PARLEY

This image by Galen Neil. Header image by Ed Sloane

SEA TURTLES

Over the last sixty years, sea turtle populations all over the world have experienced a slow and steady recovery. While the pandemic has provided a welcome break from human disturbance, this recovery is due to long term conservation efforts and laws prohibiting fishing and trade. Even with these moratoriums, leatherbacks continue to decline, and all seven sea turtle species face challenges from vessel strikes, marine debris, and climate change. Still, sea turtles have shown incredible strength over the past few generations, increasing their nesting behavior and global population numbers. What’s more, this success shows that thoughtful conservation works – even for the most vulnerable animals. In the words of one expert, “Sea turtles are survivors. They’ve been around for millions of years. They’re very resilient and can adapt.”

OVERFISHING

Being a fishery observer is one of the most dangerous jobs in the world. Traveling the oceans to record illegal, unreported or unregulated fishing, observers frequently face harassment from fishing crews. Far from any authority, many work without legal protections, and tragically more and more observers are vanishing under mysterious circumstances. “We’ve recorded one or two deaths of fishery observers every year since 2015,” said Liz Mitchell, president of the Association of Professional Observers. “The playbook of each disappearance or death is the same. The news leaks out from unofficial sources. The families are told: ‘We’re looking into it.’ They hear nothing.” Currently, there are no international protocols for investigating a fishery observer’s death.

MICROPLASTICS

There may be more than twice as many microplastics in the oceans than scientists previously thought. As part of a new study, researchers used trawls with superfine mesh to collect some of the smallest plastic particles off US and UK coasts. Taking this newly detected debris into account, the study’s authors raised the global estimate of microplastics from 5-to-50 trillion to 12-to-125 trillion pieces. From seabirds to whales, plastic pollution threatens the survival of many marine species. This new research suggests that microplastics may even outnumber zooplankton – the tiny, floating animals that serve as the backbone of marine food chains and help regulate climate. The study’s lead author warned the estimates could “get larger again” if nets with even finer mesh are created.

CORALS

To fight global heating, some corals are becoming more beautiful. The background: when heat-stressed, corals expel their colorful, symbiotic algae, causing reefs to turn white or bleach. Corals rely on symbiotic algae for energy, and do not survive long without it. Now, new research reveals an adaptation helping corals win their algae back. After bleaching, some corals display extra bright colors to reflect light, cool off, and create conditions that are favorable for algae to return to. “The corals produce their own sunscreen, these colorful pigments,” said the study’s lead author, “It’s a beautiful example of how nature regulates processes. The corals change their physiological setup and respond to an environmental cue.”

GLOBAL HEATING

A new study had revealed global heating’s disproportionate effect on deep sea life. Led by scientists at the University of Queensland, an international research team measured “climate velocity” – how quickly animals must migrate to stay within preferred temperature zones. During the 20th century, climate velocity was 2-to-4 times greater in deep waters than it was at the surface, a finding researchers attribute to the deep ocean’s more consistent temperatures. The study’s authors also warned that climate velocity at depths of 200-1000m could be 11 times higher than at surface waters before the year 2100: “Our results provide strong motivation to consider the future impacts of ocean warming to deep ocean biodiversity.”