Into the storm

So far we have been lucky with the weather, with calms seas and warm temperatures. Hard to believe that we are in such tranquillity in the middle of the Atlantic Ocean known for its bad temper. Murphy’s law lived up to its name! After we picked up the 17^th station, we headed right into a storm. We weren’t alarmed by the sudden change as the mighty RRS Discovery is built to handle far tougher storms. Nonetheless, the scientific crew were a bit excited with many of us trying to capture some amazing pictures, while we get shelter inside. Rain or sunshine, the operations have to go on! But fortunately the storm had subsided by the time we reached our next station

Finally some science!

We reached station 18, working backwards from station 39, picking up more and more instruments along the way. We started looking at the recorded data from the stations with a special focus on the state of the instrument over its working cycle and the quality of the data. There is nothing more than a pristine clean seismogram that can make a seismologist happy. We are all overwhelmed by the high quality and richness of the dataset. This was somewhat expected because of the high-end, state-of-the art broadband seismometers that we used. However, one has to remember that these instruments operated exceptionally in a formidable environment, under 5 km of ocean water. To our delight the data recorded is good in comparison to some of the data recorded on dedicated seismic stations on land. This can only yield high quality research in the very near future!

Here we show a seismogram recorded on one of our stations for a teleseismic earthquake with a magnitude of 7.6 that struck Chile on Christmas Day 2016.

Party at sea – Happy Birthday Kate!

Amidst the hustle and bustle on the ship, today is a special day for the Principle Investigator of this research expedition. Today is Dr. Catherine Rychert’s birthday! Despite her efforts to closely watch our every move in the nerve center of operations – the main lab, we managed to prepare a small surprise for her. We designed a poster and a birthday card (pirate themed) at 4 am while recovery operations were underway! We gathered in the galley just before dinner at 17:15 hours, putting up a poster and setting the music system to play a birthday song. As we were approaching our next station, Kate couldn’t leave the main lab as she was on watch. This was perfect for us! We left one radio-on in the lab. At 17:30 hours Mike Kendall, the senior scientist, called Kate on the radio to urgently come up to the galley for a meeting. As Kate hurriedly came up to the galley, we started singing and played the birthday song and caught her by surprise. I guess she was totally embarrassed but thoroughly enjoyed it! Thanks chef Wally for a delicious chocolate cake.

Recovery in the darkness!

Early this morning, we were approaching site 30 to recover two more instruments from the bottom of the ocean. We generally prefer night-time recovery because the instruments have a beacon that starts flashing a bright white light as it reaches the surface. This is an extremely efficient way of spotting the instrument. The instruments also have a reflect flag to help spot it during the day. However, things can get a bit tricky and tense at night if the beacon fails. This is what exactly happened, or so we thought! The instrument was supposed to rise to the surface at 03:15 hours. Those awake were all out on the deck trying to spot a floating instrument. We were lucky to have a bright full moon to help us. A couple of us were on the bridge with binoculars and night vision scopes staring into the horizon. On the other end, the OBS group was using their acoustics system to continuously range the instrument and determine how far it is from the ship. This helped us steer the ship so that we get closer to the instrument. As we started approaching the instrument, it surfaced and the beacon started flashing! That probably was the tensest moment we had, knowing that the instrument was somewhere out there in the darkness and out of our sight. It turned out that the instrument had extra weight stuck to it and thus slowed its ascent to the surface. Everyone had a sigh of relief when the instrument was finally on deck and secured!

The entire operation lasted about 6.5 hours, followed by a short 140-minute transit to the next station. We are now recovering about 4 stations, i.e. 8 instruments a day, as we steadily sail from the mid-Atlantic ridge towards West Africa.

From the Galley to the Gym

We have been 10 days at sea already! Life on board is now getting into a routine, most times losing count of which day of the week it is. Having recovered 7 out of 39 stations, i.e. 14 instruments in total, the recovery procedure has now become pretty much “standard”. Everyone involved with recovery, from the bridge to the deck, works like a symphony. But life on the ship is not only about science and station recovery. We need to be fed good, healthy and delicious delicious food. The RSS Discovery is a big ship, and with such a ship comes a large, well-equipped kitchen. Two chefs, Peter and Wally, man the kitchen. A big ‘British-style’ breakfast is served at 7:30 am sharp. Lunch is between 11:30 – 12:20, and dinner is served between 17:30 and 18:30 hours. For those working on night shift, they can have their food served later. In addition to these strict meal times, there is always something to eat or nibble; salads, cold meat, fruits, and ice cream are available 24/7. Oh, and did we mention the desserts? They are ‘homemade’ and yes, they taste delicious!

Chefs Wally (left) and Peter (right) take a break for a picture

Such tasty pleasures come at a price. Yes, you got it right – painful workouts at the gym. The ship has a small but well equipped gym. The crew have a choice of treadmill, cycling, rowing, stepper, and weights. Surprisingly (or not), the gym is indeed a busy place and people use it throughout the day. Perhaps now is the time to go and burn some calories!!

Crossing the line

Along with the hard work and science comes a bit of fun. Few people get the opportunity to sail across oceans, and lesser get the chance to cross the equator! There are many myths and legends that are related to the ‘Line Crossing’, with some involving strict rituals too! Some of the crew, who were on this same mission last year, crossed the equator and are now called Trusty or Honourable Shellback, often also referred to as Sons of Neptune. However, those who have not yet crossed are called Pollywogs (for now). Today we crossed the equatorial line at 16˚ 10’ W longitude. As we crossed the line the ship sounded its bells and the captain welcomed everyone to the southern hemisphere. Although we did not perform the “Line Crossing” ceremony (yet!), many of the scientific crew took time to relax on the foredeck as we sailed on to the next station.

Two more instruments on deck

Following last night’s endeavour, we were back in the main lab by 6 Am to oversee the recovery of the next station. The entire recovery process lasts a few hours. First the ship comes to a halt about 2 km away from the deployed site. The seismology and magnetotelluric groups will attempt to communicate with their respective instruments. If communication is difficult, the ship would slowly move closer to the instruments. Once communication is established, the OBMT instrument is released from the ocean floor first. Then, a survey establishing the exact location of the OBS is performed by sailing along a circle of 2 km radius around the original OBS deployment site. Following the survey, which lasts about an hour, the OBS is released. The instrument starts the burn cycle which last about 10 minutes during which a trigger is sent to release the weights that hold the instrument down on the ocean floor. The techs continuously communicate with the instruments to ensure that the they are rising steadily. Both the OBMT and OBS can take between 1 to 3 hours to rise to the surface, depending on the depth they are at. As the instruments rise to the surface, the ship comes to a halt at a safe distance and everyone on deck keenly stare into the horizon to spot the instrument when it come up to the surface. Both the instruments were recovered by 12:30 in the afternoon. Another happy moment for all of us!

The next station is a fair distance away. The estimated time of arrival is 9 Am on 8^th March.

An acoustics unit that is patched into the ships transducer to communicate with the ocean bottom instruments.

Research techs hard at work

If the flashing beacon fails, we have an “ecto-graph” (think of ghost busters) to find the instruments!

First station – 2 instruments secured on deck

The moment all of us on board the RRS Discovery have been waiting for! The first two instruments, an ocean-bottom seismometer (OBS) and a magnetometer (OBMT), have been recovered from deep down the abyss of the Atlantic Ocean. Everyone is excited and in good spirits, cheering at each step, from initial communication with the instrument, confirmation of its rising, getting a visual of the instrument at the surface, and finally, seeing it back on deck! The first station is always tricky as the ships acoustics get tuned to communicate with the instruments. There were quite a few tense moments when the techs switched between different ship based transducers, dunking transducers and acoustic boxes to establish communication with the seismometer and the magnetometer. While the instruments were rising from the bottom of the ocean, the techs got to work patching their acoustic box directly to the ships transducer, by-passing other patches to the working labs. This was done to reduce noise and signal degradation. The instruments were finally back on deck at 23:58 hours.

Despite many of us having been on similar expeditions before, it is always a sigh of relief to see an instrument being recovered. Each instrument is literally left at the bottom of the ocean with no connection to the surface and operating on its own batteries for an entire year. So many things could go wrong that can result in a failure, such as problems with the electrical battery, mass-release, buoyancy issues, a wrong position, integrity of the structure, or simply the station is lost somewhere beyond our communication range!

Next, 76 more instruments to be picked up! While we transit for 7 hours to reach our next station, many of us are off for a well-deserved rest, while a few stay on night watch.

Deck cleared for the instruments – 1 day to go!

With just less than a day to reach the site where we deployed the last ocean bottom stations a year ago, all on-board labs are now set up, and the deck and hanger cleared. The hanger and deck will be used to store the instruments while we transit back to land. The principal science officer called for a meeting to iron out the recovery procedure to be undertaken. Top on the agenda was safety during operations on the deck, where heavy machinery will be in use. It is also important for the watchstanders to ensure that the operations progress with ease and efficiency.

The Main Lab

The Main Lab is at the heart of the operations. This station is manned by scientists, or better known as watchstanders, who monitor each and every operation that is underway, from ship navigation, to monitoring continuous operation of ship-board instruments, and communications with the crew and the research techs who operate the ocean bottom instruments. Watchstanders operate 24/7 on 12 hour rotational shifts with at least 2 scientists during every shift.

The main lab is equipped with numerous displays that show real-time information from ship-board devices. The monitors are usually setup to display navigation from the bridge, a single-beam echo sounder that gives the depth of the seafloor, a multi-beam echo sounder to image the bathymetry in 3D, a sub-bottom profiler to image the sediments on the seafloor, a gravimeter, real-time GPS system, wind and wave energy, and finally CCTV to monitor deck operations.

The outer deck and hanger

The deck and hanger have been cleared to make space for the recovered instruments. Towards the end of the expedition this space would be taken over by shiny yellow instruments, crumbled up one next to the other.

The OBS and OBMT labs

These labs are dedicated to seismic and magnetotelluric instruments. The research technicians in these labs conduct surveys to determine the true position (latitude and longitude) of the instrument on the seafloor as it might have drifted during its ~5000 m journey to the bottom of the ocean! They are also well equipped to dismantle the delicate electronics of the seismograph, and the magnetometer and extract the precious data that was recorded for a year!

Preparations underway for recovery

We are now 2 days away from reaching our first station-recovery site. The three participating labs – LDEO, SIO and IPGP are ready and excited to examine the state-of-health of the recovered instruments from the ocean. The examination involves looking for any physical damage, checking internal electronics including batteries, motherboard and data loggers. The environment at the bottom of the ocean is quite hostile, the equipment would be under very high water pressure (a water column of more than 5 km) that may compromise the physical integrity the instruments, leading to water damage of the electronics. The specialised electronics are designed for maximum efficiency, to run for an entire year on high capacity lithium batteries. Furthermore, the data collected will be of the order of several hundred Gigabytes.

Meanwhile the scientist party have agreed on a working roster, some working 12-hour night shifts. The continuous operation is necessary to complete the mission in the shortest time possible. The people working late night shifts are, however, rewarded by amazing sunsets and sunrises.