Institut für Chemie und Biologie des Meeres
The focal point of our research on board are bacteria in seawater and sediment. These bacteria are so small that they can only be seen under a microscope. But we are also interested in something that can’t even be seen with a microscope: dissolved compounds that are found in amazing variety in seawater. We want to understand where these compounds come from and how they are used by bacteria.
The smallest forms of life in the ocean, bacteria, are the central focus of our research on board. Bacteria are single celled life forms; they are so small that we cannot see them without a microscope. Nevertheless, we want to know how many bacteria there are in the ocean; how are they counted?
Yesterday we passed through the Aleutian Islands. The Aleutian Islands are a chain of volcanic islands dividing the Bering Sea from the Pacific Ocean. We were lucky: the visibility was good, and it was still light outside, so that we could see one of the islands relatively clearly, and two others could be seen (using binoculars) on the horizon. South of the islands is the Aleutian trench, where the Pacific Ocean is nearly 8000 meters deep.
The Bering Sea is a marginal sea of the Pacific Ocean, just as the North Sea is a marginal sea of the Atlantic Ocean. But the Bering Sea covers four times as much area as the North Sea and is also much deeper. For our last two stations, we will deploy our instruments once more to depths of 3500 meters, in order to collect sediments and water.
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