Daily Journal

June 16, 2010

By David M. Lawrence

My watch – working the dawn watch – had quite the learning opportunity this morning. To conserve fuel while under sail, the SSV Corwith Cramer was running under battery power for most of the night. Watch standers, when doing a boat check, are supposed to look in on the equipment in the engine room, among other locations on the ship, and awake the engineer on call in case anything is amiss, such as when an instrument reading is outside acceptable limits.

Someone didn't notice that our battery voltage had dropped too low. The power supply system told us, however, by shutting down shortly after six in the morning when the voltage dropped below the value required for the DC/AC inverter to function properly. It shut down to protect itself while Lilian Corbin, our steward, was in the galley trying to feed the first batch of breakfasters and I was in the lab trying to finish a count of zooplankton caught in a midnight neuston tow. Our engineers quickly restored our power.

While there was no lasting damage other than possibly embarrassment, the incident proved the importance of being aware of what one is doing, how to do it, and why to do it – at sea or elsewhere. In adverse conditions, the loss of power could have led to some intensely stressful moments rather than a bit of embarrassment.

The number of plastic pieces recovered in our trawls has dropped off a bit the past day. It is not surprising. One thing that should be obvious to any observer after a few days at sea is that nothing in the ocean is distributed evenly – not even the water. There are patches with a lot of stuff and patches with not so much stuff. The Sargasso Sea itself is something of a biological desert. The waters are nutrient deficient, which means there isn't much phytoplankton productivity. Without much phytoplankton, zooplankton numbers are reduced. Numbers are reduced all the way up the predatory food chain, with the exception of humans – ultimately the top predator in the oceans.

We did happen to net an interesting predator last night, however. The scientific staff were surprised to find a dragonfish, a deep-water predator, in our midnight neuston tow. Dragonfish normally live in the eternally darkened middle depths of the ocean – the zone scientists refer to as the mesopelagic zone. No one knows why this one ended up near the surface, and in our net, but we all were delighted by this bizarre creature with big, big teeth (more like lances rather than knives), an external lighting system (made up of light organs called photophores), and a "lure" useful in enticing potential prey within reach. Compared to us, it was rather small – less than two inches – but for its fellows in the deep, it packs a fearsome arsenal in a small package.

Today the weather changed. A front has caught up with us and brought overcast skies and showers. The cloud cover had a spectacular effect on the color of the oceans. The vivid deep blue-green faded to a something closer to gray-green. But when the sun pokes through, the deep blue returns.

We are halfway to the Mid-Atlantic Ridge – a submarine mountain range that extends throughout the world's oceans. We hope to reach the ridge in the next few days before turning south to make a complete circuit of the Sargasso Sea.

By the time B Watch went up on deck to take the evening watch, the weather had moderated. It is breezy, but the clouds have parted and it looks like we'll have a marvelous sunset.

 

For more from sea, listen to today's interview with Chief Scientist Giora Proskurowski on Pacific Beat, ABC Radio Australia.