A tale of two oceans

Last night we went through the most famous shortcut in the world: the Panama Canal. We arrived in Colon, the port on the Atlantic/Caribbean side yesterday morning, and waited at anchor until our turn to travel through.

16:30 and our journey through the Panama Canal begins, though all we can see is the faint back of the ship in front of us through the rain, fog and thunder. An hour later and we’ve reached the first set of three locks, to raise us up to the level of the large Lake Gatun, entering behind the Baltic Sky. It’s a strange sight to see such a remarkable feat of human engineering surrounded by lush rainforest, with alligators spotted in the water by some. By this point the thunderstorm is fully raging with sheet lightning filling the sky and heavy tropical rain.

Approaching the first lock, with rainforest
on either side (credit: Emma Gregory)

Alligator seen on the bank (credit: Miguel Maqueda)

A few employees of the canal come aboard the ship to throw lines to be attached to the ‘mules’, which are small vehicles on a track that pull the ship through the locks and keep her steady whilst they’re filling with water.

Inside the lock (credit: Emma)

View from the back deck of the lock gates (credit: Emma)

One of the 'mules' steadying the ship (credit: Miguel)

Once we’re through this first set of locks we enter Lake Gatun, which stretches almost to the other side of the thin isthmus. Sadly it’s dark by now, so our only views of the rainforest and islands come with the brief flashes of lightning.

00:00 and we’ve reached the far side of the lake, to the second set of locks which bring us back down to the height of the Pacific Ocean. The surface of the Pacific is actually at a slightly higher elevation than the Atlantic Ocean. This is because the Atlantic generally contains saltier and denser water, so for the same mass of water per area, it occupies less volume. Sea surface height is also affected by spatial differences in the strength of Earth’s gravity, bathymetry (topography of the seafloor), and weather pressure systems among other factors. You can check out https://sealevel.jpl.nasa.gov for some more information.

Map of sea surface height (credit: ESA)

The storm has petered out by now so it’s no longer raining. We reach the end of the locks by ~1:30, and begin our final leg of the transit to dock at Balboa.  

In the next few days, our final mobilisation will take place before the real science begins: taking on water, supplies, and some extra personnel. We will then head off into the Panama Basin in search of our spreading ridge to begin the oceanographic and heat flow measurements this cruise is concentrating on. 

Looking towards the Pacific from our berth in Balboa
(credit: Jowan Barnes)