PUPCYCLE Day 2 -Phytoplankton Chillin’ with the UCBC!
Saturday, May 25, 2019
PUPCYCLE 2019 – Phytoplankton Chillin’ with the UCBC!
The R/V Oceanus continued to face heavy seas as we steamed toward our first Incubation Site along the California Upwelling Zone (CUZ). The CUZ is concentrated along the California coastline as noted in Figure 4. As winds move surface waters away from the coastline, colder water rich in nutrients moves toward the surface.
Figure 4 – Water temperatures are typically colder adjacent to shore than further offshore for most of the California coastline north of Pt. Conception—the bend in the coastline at 34.5 N. [Image courtesy of Sanctuary Quest 2002, NOAA/OER.]Researchers onboard the R/V Oceanus are conducting experiments to observe the response of phytoplankton in this region. (More on that tomorrow.) Phytoplankton are the plants of the sea and their need for sunlight to complete photosynthesis dictates that they hang out near the surface. These microscopic organisms also need nutrients in order to survive. That’s where upwelling provides assistance. Nutrients that run-off from land join other dissolved organic material (DOM) and mix with the chemicals in seawater to create all the nutritional requirements needed to sustain the aquatic food web. Much of this material sinks to the seafloor where it remains until an upwelling event occurs.
Figure 5 – Upwelling events occur when winds push warmer surface water away from the coastline and deeper nutrient-rich water moves toward the surface. [Image credit: https://seos-project.eu/oceancurrents/oceancurrents-c04-s01-p01.html]Figure 5 illustrates the type of upwelling events that occur along the CUZ. These upwelling events occur seasonally and an event may last for several days. When the winds subside or change direction, the upwelling also subsides and gives rise to a period of relaxation in the water column. The relaxation period can persist in an area of upwelling for days or weeks. The interaction between these upwelling and relaxation periods is referred to as the Upwelling Conveyor Belt Cycle (UCBC). This cycle is setting for our research expedition. Scientists are searching for a column of water that is currently experiencing a UCBC Relaxation phase to collect the phytoplankton being used in the Incubation Site #1 experiments.
Figure 6 – Marchetti Lab students launch and recovery the CTD equipment they will use to collect water samples containing millions of phytoplankton. [Image credit: Miriam Sutton]PUPCYCLE 2019 is the first sea experience for many of the students onboard and today provided some time to adjust to their sea legs while also practicing some of the protocols they will be using once their experiments begin. The students will collect the phytoplankton by launching and retrieving a CTD through the water column. (See Figure 6) A CTD measures Conductivity, Temperature, and Depth while also housing 12 niskin bottles. These bottles look like thick grey PVC pipes with spring closures. The bottles are open on deployment allowing water to flow through as the equipment is lowered through the water column using a crane system on the R/V Oceanus. Once the selected depth is reached, a computer signal from the ship triggers the seals to snap shut on both ends, capturing the water and microscopic organisms inside.
