Biology - Oceanography Report

Oceanography Report

        This oceanography boat trip was an exciting and memorial experience. I remembered that I had trouble sleeping the night before the trip because I was so excited. The boat that we boarded was called the “R/V YellowFin”. Before the trip, I viewed the Southern California Marine Institute’s website to look at the Yellowfin’s specifications. The boat possesses some very heavy equipment and winches such as Hydrographic winch, Articulating crane, Main drag winch, and Stern a frame. Modern features of the boat include GPS and cellular phone.  As we boarded the boat, I quickly noticed the large crane that is used to navigate the dredge into deep water. I believe this was the articulating crane. Another device that the boat utilizes is the biological dredge. This device is used to capture sediment sample at the bottom of the ocean. The weather conditions at the start of the cruise was sunny skies, about 76 degrees, and the approximate wind is 2mph. As we got deeper into the sea, the air got colder and wind speed picked up.

        The captain stopped the boat just off the port of Los Angeles and near terminal prison. At the first station, the person explained to us what he was doing and the equipment that he was going to use. First he explained to us the Secchi Disk (named after Pietro Angelo Secchi) and how it is used. The Secchi Disk is a circle shaped disk that is used to measure water transparency in the ocean. Two people were instructed, one person manning the winch used to lower the disk and one person holding the rope lowering the disk. The person lowered the disk and observed when it disappears and raised to see when it reappears. The depth at which the Secchi Disk disappears from view was 17 meters.

One of the most important things that I learned during the boat trip was when we hauled up the sediments for analyzing.  When the person dropped our first sediment sample to the table, I was amazed to see that the sample was fine clay. The reason why the sample was fine is because of denudation the erosion of land. Also the sample was closer to land which makes it more likely to find such sediment. The color of this sediment sample was greenish/brown. The reason for this kind of color is the green algae. The color brown may suggest there is manganese in the sample. The sediment sample did not admit any noticeable odor. The organisms in the sediment sample were quite shocking. We found small organisms such as small worms, swimming crabs, brittle stars, shrimp and clam shells. We even found a tentacle part of an unidentified organism. Next up is the water sample. We measured at 1 meters, 5 meters, and 10 meters deep. The temperature dropped as it got deeper; this was explainable because the sun’s rays can’t penetrate deep into the ocean.  The pH levels remained stable throughout the three measurements. The DO was also stable throughout the measurements. The salinity of the water at 1 meters deep was 33.2 compared to 33.90 at 10 meters deep. The reason for this is that the deeper you go into the ocean, the denser the water is and it has a higher salinity.