The final waiting for arrival at the first station ended with a phone call from the bridge saying that we were on station at 0500 on 13 April. The seas were moderate and the winds were in the 10 to 15 kt range, fine for work on station. The air was about 17C, cooler than the sea water, which had a temperature around 19C. The science watch for the midnight to noon period was up quickly and the first up was a 1-m2 MOCNESS tow. The net system was a bit late in getting into the water because the deployment through the stern A-fram required some experimentation to see how best to get it over the 10-m2 MOCNESS, which was positioned within the stern A-frame area. The tow went well with Larry Madin taking the lead on flying the net for the first part of the tow and P. Wiebe taking the last part while Larry coordinated preparation of the SCUBA dive. There was lots of excitement when the net system came on board around 0930 and a flurry of activity as the samples were moved from the deck in buckets chilled with ice packs to keep the samples cool to the walk-in refrigerator. They were stored there until they could be photographed and picked for large organisms in the wet lab, and then split into fractions for additional live picking of smaller animals or preservation in either alcohol or formalin.
A blue-water dive was next up and Larry Madin, Erich Horgan, James Brinkley, and Keegan Plaskon (latter two from the ship) went out in the RHIB (Rigid Hull Inflatable Boat) for about two hours of collecting of the more fragile zooplankton that are usually destroyed by collection with nets.
The first tow with the 1/4-m MOCNESS in the early afternoon of the 13th was not successful. A problem with the battery power in the underwater unit resulted in a loss of signal about a third of the way through the deployment. Only a single sample was obtained, but it also proved to have a number of microzooplankton species of interest.
The final bit of rigging of the 10-m MOCNESS trawl system was completed and by 1600 it had been launched off the stern and it was going down to 5000 m. It took about 4 hours to deploy to it to the maximum depth and it was a very smooth deployment. Once at depth, the ship’s speed was increased to get the angle of attack of the net frame up to the normal towing angle of about 45 degrees and to let the net system rise up with the increased velocity. When the winch started to haul in the towing wire at the slow rate of 10 m/min, the winch started up and then stopped. There was a lot of activity for a while to try to determine what caused the winch problem. In the end, the winch was enabled by the ship’s engineers so that it could haul in at 6 m/min. With 8000+ meters of wire out, it appeared it would take 22 hours to haul the net back in. In reality the wire was hauled in less time because the speed of retrieval increased as more wire came on board, and the net system reached the surface at 0740 on the 14th of April some 16 hours after the tow was begun. The recovery of the frame went very smoothly with a combination of the A-frame and air-tuggers pulling the frame on board and down on a pair of stanchion used to secure the top portion of the trawl frame. Once the frame was secure, a number of the morning watch pulled in the nets, which only took about 10 minutes. The newly designed trawl nets fabricated from very fine 335 um nylon mesh proved successful and were in fine shape after the tow. This tow also had some flaws. One cod-end bucket that had not had its fasteners taped or rubber-banded was lost (Net 2) and the tab on net bar 3 broke off during the tow. The cable and swaged fitting from this net bar was found in the cod-end of net 4. This meant that net 1 fished from 5000 to 4000, net 2 fished from 4000 to 3000, and net 4 fished from 3000 to 1000. When net 2 was closed, net 3 closed with it and never was open. When net 3 was supposed to be released, the cable and swaged fitting plus part of the tab fell into the open net 4. Because of the length of the tow and the repairs needed to get the trawl back in service, the second tow with this system was scrubbed.
The MOC-10 catches, while not spectacular in terms of biomass caught, were very interesting in terms of the species collected. While water collection with a 30 liter Niskin bottle was being conducted, the taxonomists were bunched in the ship’s wet lab processing the MOC-10 samples. It was clear that many new animals were caught in the deep nets especially the one that sampled the 3000 to 1000 m zone. There were many shrimp and gelatinous animals including ctenophores. Martin Angel found at least two new species of ostracod, one he knew about and one he had not seen before. Tracy Sutten had a male angler fish in very good condition - this specimen was from a group that is only known to the generic level. And he had other specimens of fish species that are rarely ever caught.
The afternoon of the 14th went quickly in calm seas, clear skies, and bright sunlight. The quarter meter MOCNESS haul came first around 1330. The underwater unit that had failed during the first tow was replaced with the one from the MOC-10, and it and the options case with the fluorometer attached worked very well. This tow was a bit of a bear because it was difficult to keep on the intended course and the bridge had to keep changing speed to keep the towing wire clear of the ship’s starboard quarter. The net system came on board around 1600 and the catch again was of great interest to a large group of people, especially those working on the microplankton. Right after the 1/4-m MOC came on board, Russ Hopcroft put his Reeve net in for a deep (500 m) vertical tow during the dinner period to collect larvaceans and other live animals for identification and photography. Larvaceans are particularly fragile animals and rarely come up intact in the MOCNESS. The Reeve net with its very large cod-end allows the fragile animals to be collected more effectively.
A 1-m MOCNESS night tow was started about 1800 and this tow was completed in under 3 hours, which kept us on schedule and made it possible for the divers to leave the ship in choppy seas by 2130 for their night dive. They arrived back about 1115. Both the MOCNESS and the diver’s collections provided additional animals that had not appeared in the earlier tows and divers.
The last activity for the first station was another 1/4-m MOCNESS tow and it also was an ill-fated tow. With about 600 m of cable out and the net at 290 m depth, the deck unit lost signal with the underwater unit and data collection ceased. Something catastrophic happened and the only recourse was to retrieve the system. With the winds picking up sharply since the early evening (they were about 17kts around midnight, up from 8 kts before the divers went out), the decision was made to call it quits at this station and set sail for Station 2.
During this two day period, there was tremendous activity in the forward biochemistry lab where the Applied Biosystems Hitachi gene sequencer was located. The “UCONN Team DNA” was working around the clock to prepare and sequence animals. A number of species identified by the taxonomic experts on board were placed in a queue for sequencing and a dozen or more have been successfully sequenced. Of particular note is the fact that Martin Angel has identified a number of ostracods from the samples and a number of these have been sequenced. These are the first sequences ever produced for marine ostracods. A description of the work by Rob Jennings follows.
“Team DNA” consists of Rob Jennings, Brian Ortman, Paola Batta-Lona, and Ebru Unal. Honorary Team DNA members Leo Blanco-Bercial and Barbara Costas have also been very helpful. We have been hard at work since before the ship left the dock. After an excellent ship-board setup and tutorial from ABI Representative Bob Newman, the team improvised a few changes to the system to accommodate sequencing on a rocking boat in the humid tropical air. The first sequencing test run (on organisms collected previously) was a success. We have implemented a workflow system so that organisms are catalogued, extracted, and analyzed as quickly as possible on an around-the-clock basis. Thanks to the hard work of our incredible team of taxonomic experts, we have catalogued approximately 250 individuals from Station 1, representing 9 phyla and 125 species. At least two of these species are new to the taxonomic experts, and many (including the majority of the pelagic ostracods), have never had their DNA sequenced. The majority of the species we are analyzing now are from the first MOC-1, but many individuals from the MOC-10, as well as several Reeve net and ring net specimens, are in the works as well. The first sequences are currently being edited and finalized, and approximately 100 more will soon be collected.
Also of note are the many deep-sea fish and their larval forms that have been collected and identified by Tracey Sutton and Lalithambika Devi. A report by Tracey follows.
A total of 36 species (17 families) were identified by Tracey Sutton from 640 specimens collected using the three MOCNESS systems. This species number is expected to increase when analysis of larval forms (66 specimens) is completed by Lalithambika Devi. As expected, the genus Cyclothone dominated the catches, with three species (C. pallida, C. microdon, and C. braueri) comprising about 80% of the catch. The rarest specimen caught at Station 1 was a male anglerfish of the genus Linophryne. Male anglerfishes are so poorly known that many can only be identified to genus. Tissue was taken for DNA sequencing, which is the best bet for matching males with the rare but better known female anglerfishes. Likewise, tissue was taken from the black dragonfish Eustomias obscurus, one of 115 species of a genus of fishes that are differentiated almost solely by the barbel. Skepticism has been raised about the validity of all of these species, and again, DNA sequencing is the best option for testing their validity. With half of all species so far taken from a single 10-m2 MOCNESS tow, hopes are high that many more rare species will be collected during further sampling.
Finally, the tintinnids, a microzooplankton group, are being studied by Barbara Costas. A variety of specimens have been collected from surface drift tows made with a small ring net equipped with 10 um mesh, from water collections from depths of 75 and 10 meters, from the 1/4 m MOCNESS tow #2, and from the deep Reeve Net tow. Some of these species have had their DNA processed and are undergoing gene sequencing. One interesting finding is that the tintinnids are occurring much deeper in the water column at station 1 than expected.
All in all, the work at Station 1 has been quite successful and there have been several "firsts" ranging from the depth of towing (5000 m) with a trawl equipped with very fine plankton mesh netting, the sequencing of zooplankton at sea, and the discovery of some new species.