Oceans host 80 percent of the planet’s biodiversity, provide employment to hundreds of millions of people and help to regulate the Earth’s climate, absorbing a quarter of all of the carbon dioxide that humans put into the atmosphere.
That is why, at the recent Commonwealth Science Conference 2017, hosted in Singapore and organised by the UK’s The Royal Society and Singapore’s National Research Foundation, one of the themes was “The Future of Oceans”. During one of the breakout sessions, three scientists shared more about their latest work in protecting and studying the water bodies.
Protecting Singapore’s marine biodiversity
The waters around Singapore are teeming with biodiversity, including 265 hard coral species, more than 200 sponge species and more than 100 marine fish species.
To help ensure their survival, Dr Karenne Tun and her coastal and marine division at the Singapore National Parks Board’s National Biodiversity Centre have developed a modelling tool that can simulate species’ movements in the waters.
For example, the computer program can be used to analyse where coral larvae may settle after the species’ spawning period.
“The idea is that we can use this tool to tell other government agencies who are overseeing developments in the marine environment, look, you need to avoid this particular area during this particular time,” said Dr Tun, who is director of the coastal and marine branch.
“If we know that certain areas are scheduled for development, we can also use the program’s findings to negotiate for certain areas to be conserved. If we’re going to set up a nursery for species conservation, it can tell us where would be the best place for it,” she said.
The program incorporates several streams of data, including information on the target species’ biological traits, hydrodynamic models of Singapore’s waters and weather forecasts.
“We need to give it good data, so we’ve focused on data-rich habitats and species so far. For example, we have more than 30 years of local knowledge about coral reefs, intertidal habitats and mangroves,” said Dr Tun.
She noted that the program’s theoretical results need to be validated through actual observations. She said: “We’re hoping to follow up on this work next year and put settlement tiles to validate observations on the ground with the model results that we have.”
Improving ocean and climate models
The turbulence in oceans is responsible for the water bodies’ mixing of temperatures, salt, nutrients, chemicals and dynamical qualities such as momentum.
“Understanding this ocean mixing is crucial to understanding how the ocean works, and how to represent that in our ocean models and thus climate models,” said Professor Stephanie Waterman, an assistant professor at the University of British Columbia’s (UBC) Department of Earth, Ocean and Atmospheric Sciences.
The small scale motions that make up the turbulence, however, are very difficult to measure, due to the need for highly sensitive sensors and noise-free platforms on which to mount them.
Taking advantage of recent technological advances, Prof Waterman and her UBC team have deployed an ocean glider equipped with such sensors to carry out measurements in the Arctic Ocean, where the environment is changing faster than in anywhere else on Earth.
“These autonomous gliders have very high endurance and very low noise floors because they have very few moving parts, and those parts move very slowly,” she said.
During the August 2015 mission, the UBC glider travelled 185km in 11 days and collected 345 CTD (conductivity, temperature and depth) and turbulent microstructure profiles.
“To put that into context, that is the same order of magnitude of profiles collected for the whole Arctic up to that time. Our mission was the densest microstructure sampling scheme in the Arctic Ocean to date, and the first to statistically demonstrate the natural variability of turbulence in the region,” Prof Waterman said.
The team’s analysis of the collected data – which is ongoing – showed that the ocean’s turbulence is weak in most places in the area of focus. This is important as strong turbulence could lead to vertical heat flux which can melt sea ice and contribute to rising sea levels.
“Thankfully, our measurements suggest that the background turbulent energy would have to increase by an order of magnitude for that to happen,” said Prof Waterman.
Making fishing sustainable
About 130 million tonnes of fish are caught from the oceans annually, both legally and illegally. Furthermore, globally, 260 million people are involved in marine fisheries’ work, either directly or indirectly.
Professor Rashid Sumaila, a professor and director of the Fisheries Economics Research Unit at the University of British Columbia’s Fisheries Centre, gave these statistics to show how important oceans and their fishes are to mankind.
Persistent overfishing, however, has resulted in 90 percent of fisheries fully exploited and facing collapse, and one of the main culprits causing it is subsidies for fisheries.
In May 2017, the United Nations estimated that fishing subsidies total as much as US$35 billion globally, of which US$20 billion directly contributes to overfishing. “We’re giving these subsidies without thinking of the consequences on fish stocks,” said Prof Sumaila.
“Furthermore, these subsidies are now hurting small-scale fishers. Globally, only 16 percent of the subsidies go to them, while the bulk of the subsidies go to large-scale fishers, so not only are these subsidies bad for fish stocks, they also aggravate inequality,” he added.
In a 2015 research paper, he also recommended that the high seas be closed to fishing. The Earth’s waters are now divided into Exclusive Economic Zones (EEZs), where countries retain exclusive rights for fishing, drilling and other economic activities, and open-to-all high seas.
“We found that closing the high seas would not lead to losses in the aggregate global catch, if catches of straddling taxa within the EEZs increase by at least 18 percent on average, due to the spill-over of biomass from the closed high areas,” said Prof Sumaila.
In fact, the world as a whole would achieve net gains in catch. While some countries would gain and others lose, most coastal countries would gain, including, in particular, the world’s least developed countries.
Prof Sumaila added: “The usual reaction to the argument for closure is that it will lead to massive risks to food security, employment, revenues and profits, but our results suggest that this is unlikely to be the case. In fact, it is likely that the reverse is true.
“It would be more equitable, and environmentally and economically sensible, to close the high seas to fishing and turn them into a fish bank for the world.”
Source: National Research Foundation