Swirling, living ocean
I used to think the ocean felt vast – an endless empty expanse of water, deep and unchanging. Within a month of starting my graduate degree at the University of Washington School of Oceanography, I had learned that the ocean is neither empty nor static. The ocean is teeming with life, and not just `charismatic mega-fauna’ like whales and tropical fish, but also tiny single-celled photosynthetic phytoplankton. Plankton may seem insignificant, but there are billions and billions of them, and their combined effect is enough to change the amount of carbon stored in the deep ocean and the amount of oxygen available for us to breathe.
And the ocean water itself is alive with motion. It circulates slowly, for sure, especially compared to the atmosphere that gives us our ever-changing weather. The deep currents in the ocean travel across the sea-floor for hundreds of years, and surface currents skirting the edges of the continents move at a few miles per hour or less. The surface itself is a patchwork of eddies – a literal ocean of swirling vortices. And the internal tides we are studying criss-cross the ocean in a web of wave beams, spilling onto the slopes and breaking or bouncing off again.
Falkor cruise track overlaid on sea surface height map from satellite altimetry (AVISO), showing eddies in the survey region. Courtesy of Luc Rainville.
Our little patch of sea
So, the ocean is not empty and not quiet… but surely the ocean is huge? Surely it’s beyond our ability to ever fully understand, beyond our ability to change? You might think – floating out here on a ship with the same group of people for a month, with nothing in any direction but the endless rise and fall of the Tasman Sea – that the ocean would feel uncommonly big. I have found however, that at least for me, the opposite is true.
The longer I’m out here, the more this patch of ocean has begun to feel familiar, comprehensible, like a well-known neighborhood in the middle of a sprawling city. The Tasman Sea determines our days here – the science we can do, the measurements we can make, the birds and fish and plankton we come across, even how easy it is to sleep or shower. We are in constant motion with the waves beneath us. I feel connected to the ocean here, now that I know more about it – the creatures that live here, the moods of the weather, how to work with the Tasman Sea instead of against it.
Truth is, we are all more connected to the ocean than we realize. And we have a greater impact on it than you might expect. Here’s a simple experiment: the next time you brush your teeth or wash your face, take a look at your toothpaste or face wash. Do you see any tiny colored specs? Chances are these rough little particles are actually plastic! They are great at polishing teeth and exfoliating skin, but they often end up in the ocean and are not so great for the plankton and other marine life, who cannot digest them and die. Here on the Falkor, Randall Lee is measuring the micro-plastics coming from Australia, from near Hobart where concentrations are higher to way out here in the Tasman Sea where the ocean is almost empty of plastic.
Microplastics aren’t the only threat facing sea critters, in fact they aren’t even the worst one. As we’ve mentioned here before, the ocean is taking up a lot heat, reducing the immediate impact of global warming. It’s also taking up quite a lot of CO2 – something like 30-40% of human emissions. This gas dissolves in the ocean at the surface, forming carbonic acid and making the ocean more, well, acidic.
‘Ocean acidification’ is a hot topic right now, with clear evidence of the problems it’s causing for everything from the corals in Australia’s Great Barrier Reef to the oysters on the West Coast of the United States. Many tiny sea creatures have shells made of calcium carbonate, and they are slowly dissolving away. It’s difficult to imagine the solution, especially to a problem that seems so huge.
Microplastic filtration system set up by Randall Lee on the Falkor. Photo credit: Judy Lemus.
Simulation of microplastics released from a flood plume into Port Phillip Bay, and moved by the winds and tides, slowly spreading towards the Bay entrance. Courtesy of Randall Lee
I imagine that it’s kind of like the ocean though. You start with what is right in front of you, you work to understand your little patch of the world and treat it with respect, and it will connect you to everything and everyone and everywhere else! And, just like our internal tides, spreading out across the globe, local changes often have an unexpected global ripple effect. We are working to understand one tiny part of the ocean in order to improve our understanding of the entire climate system. But it’s the everyday choices we all make that have the best chance of protecting it.
Sunrise over the Tasman Sea looking out past the A-frame, from the aft deck of the Falkor. Photo credit: Hayley Dosser.
– Hayley Dosser, Falkor