11. Cruise Letter #10

Dong-Ha Min’s cruise letters from P18 CLIVAR/CO2 Repeat Hydrography expedition in the Pacific Ocean (2007/2008)

Letter #10

Sailing Day 35 (1/17/2008)

28 deg S, 103 deg W

We have completed our last station! Now we are steaming to the west to arrive at Easter Island. We lost 8 days in San Diego, earned (or robbed of) 2 days from leg 2, so we lost about 15% of our time from original plan. We learned that we have accomplished 85% of stations that were originally planned. So we have performed in good speed after all.

I will write about the equator crossing in a next letter as it needs some extensive description, and it was crazy…

During several days during the last week, we sailed against 20+ knots head wind and sizable swells. Although it was not severe, this slowed the ship’s speed to as slow as 5.5 knots sometimes. We could have steamed in 12 knots by utilizing 2nd engine but that would have burnt substantially more fuel, so we decided to spare that for the next leg science team who would need more fuel to fight the monster seas in the Antarctic Circumpolar Current region where waves/swells can be over 30 ft.

We have encountered number of different birds during this cruise. The first one we saw since we left the tip of Gulf of California was petrels. A small and dark brown colored petrel was found at the oil catching pan on the staging bay one night. Of course, badly exhausted. We kept it in a box overnight with water so it could gain the energy. It flew out the next day morning. We observed number of ‘tropicbirds’. They are white and some of them have long white tail (like a streamer). At least 7 of them followed us for about a week. I saw a big white ‘booby’ flying right next to us the other day. But the most interesting encounter was with a stranded/exhausted ‘red-billed tropicbird’.** I found it on 03 deck behind the bridge area one morning. It was so exhausted, and wouldn’t bother to move or care when I approached. (see picture). One student felt so sorry about the bird. I found  her to try to feed it with a bowl of freshwater and a piece of bread about an hour later…. tropicbird with a bread???? I explained to her it may not like it… not to mention exposing our food container to a wild animal. The medical officer and chief steward would have gone ballistic if they knew this. Couple hours later, when I went back to the bird to check its condition, I saw a big piece of frozen cod next to it … Oh, please…. Nature healed the bird with time. Next day morning, it flew out by its own force. I was glad it didn’t crash onto the water when it jumped**.

The water has been so clear during the last week. It is light deep blue during daytime and ‘royal purple’ of Parker ink during early morning or evening time. Our underwater water velocity measurement is relying on backscatter from small particles in the water, but we have had some difficulties in this area as the water contains very little particles… so, poor water velocity observation. We could see the rosette package down to 35-40 m from the deck on a clear day (see picture). Sun light penetrates 3-4 times this depth at 1% of surface intensity level. It’s interesting part of the nature: phytoplankton needs sunlight to photosynthesize, and here it is plenty, yet very little phytoplankton. Partly because there is no sufficient nutrients supplied from deeper water for them.

We have deployed several Argo floats during this cruise. As I mentioned before, this cylindrical float will follow the deep ocean circulation for a long time and it reports its position and observation data to the shore lab via satellite whenever they ascend to the surface by its self buoyancy control pump. We usually activate the float with a magnet to start operating before the launch. One day we ran into a puzzling situation. When we actiated the float in the main lab, other scientist in the lab started to complain…. “My isothermal water bath is going crazy!”. We were like… “Water bath what???” It turns out the strong electromagnetic interference from this float ‘somehow’ messed up a circuit board of his isothermal water bath in that area. We moved the float further away from him, and the problem got solved. Another senior technician told us his similar experience in the past. Long time ago, when he was using a chart recorder for lab analysis on a ship, he was puzzled by random ‘hick up’ of his chart recorder with no apparent reason. He kept losing his precious samples due to this mysterious disturbance (they didn’t have computer interface back then). Then one day, by accident, he found that whenever the ship uses a walkie talkie above his lab, his chart recorder went crazy. So they made an agreement. The ship’s crew would notify him first before they turn on their walkie talkies above his lab. Next time you see your coffee maker act up, look around to see if there is a scientist working on something weird…

We will arrive in Easter Island tomorrow morning at 0700. It’s been quite an eventful but successful (despite all those challenges) expedition, so I am grateful. Now I need to prepare my lecture next week…

Whiskey Tango Echo Charlie out…

Dong-Ha Min

on NOAA ship Ronald H. Brown in the South Pacific Ocean

(P.S. from shore) ** I initially incorrectly identified this bird as ‘masked booby’ and wrote the description based on that assumption concerning it may drown when it flied out of the deck, as boobies can drown without sufficient strength to fly out of water. My sea bird expert friend, Tony Amos later pointed out to me that was a ‘red-billed tropicbird’. Although they are probably not good at swimming, the red-billed tropicbirds are good plunge-divers.