
For more than three weeks, we have been underway aboard the Sonne as we transect the Pacific. While we carry out our research around the clock, others are also working night and day. The Sonne does not operate itself - the engines are continuously working. Moreover, the 70 people aboard need power, water, and heat, and we need special technical support for our equipment.

The brand-new CTD from ICBM – Germany’s largest CTD - is being used for the first time during this research cruise with the Sonne. In addition to valuable data, the CTD brings 24 large bottles of seawater from different depths on deck. Not ‘just’ water, but up to 480 liters with every cast.

We have been on board Sonne already for 15 days; it feels like we have been here since forever. We know where everything is and we are so used to our working space. But it was not always like this...

The microorganisms in the ocean enjoy the sun and warmth of the equator, just as we scientists do when we are not working. Here in the equatorial upwelling zone, microorganisms grow well because of the extra nutrients that are brought to the ocean’s surface by upwelling (upwards movement) of water from the deep ocean. As a consequence, in certain depths of the water column, oxygen is consumed faster than it is supplied via circulation
This morning at 6 a.m. we ended our 24-hour sampling at this station, and continued our journey north. Neptune, of course, noticed that we had passed the equator without permission; he visited us in person.
With the sunrise came our last samples – some of us had worked for 24 hours without pause, other teams had divided the work into shifts. In any case, at breakfast the mess hall (the cafeteria) was quite empty. And in the labs, many of which otherwise are extremely busy the whole day, the lights were out until late morning.

We have finally reached the equator – the boundary between the northern and southern hemispheres at 0 N and 0 South. But we aren’t just anywhere on the equator: we are exactly at the point at which one step in the right direction can turn today into yesterday, and visa versa. Our station is exactly on the international date line between 180 W and 180 E.

We are rapidly approaching the equator. Tomorrow, we will begin our first twenty-four hour continuous station, in order to sample the water column for an entire day/night cycle. We will have a very long work-day! Someone else is also waiting for us: Neptune, the ruler of the ocean…