Scheduling sleep into a 24-hour workday

March 18, 2009

The return to iceberg C-18a marks the end of testing and the beginning of sampling. Some teams have been studying the iceberg using CTD casts and laser scanning while others have been collecting water and trawl samples. Daily meetings are used to schedule instrument deployments (called science events) for every hour of the day and night, to make full use of the ship time and so each research team can collect as many samples as possible. The ROV, UAVs, LSTs, and profiling reflectance radiometer (PRR) sensor all require daylight, so these instruments are favored for daytime deployments. Conversely, MOCNESS trawls are favored for overnight deployments, between about 10 PM and 5 AM, because zooplankton migrate to different depths based on a variety of factors, including food, season, and the amount of light in the water. Since the amount of sunlight varies with time of day and cloud cover, trawling at night reduces variability in samples caused by light-induced migrations (called diel vertical migrations). Also, it is thought that some plankton avoid nets if they can see them in the water; so trawling at night reduces the potential for net avoidance. Other science events are less light-specific and thus are used to fill the gaps in scheduling. These include CTDs, towfish water samplers, and sea surface mapping.

Some science teams are now on a nocturnal schedule, sleeping during the day and deploying equipment at night. The mess hall accommodates such odd hours; some form of breakfast food (usually hard-boiled eggs in addition to cereal and toast) is available at every meal. Scheduling science events also requires consideration of the people involved. For example, involvement in daytime ROV and nighttime MOCNESS deployments would not allow any time for sleep and would wear a person down by the end of a 40-day cruise.

Support staff, which includes the marine technicians, marine science technicians, electronics technicians, and information technology technicians, also work to accommodate a 24-hour day. Shifts are twelve hours each day, instead of eight hours as it is on land. Since work happens all hours of the day, at any hour someone could be sleeping. People walk quietly down the hallways past others’ rooms to avoid waking those with opposite sleep schedules. It also means that no matter what time it is, some form of scientific sampling is happening.

—Amanda Kahn