Presentation Title

Feeding Selectivity of Marine Copepods on Three Microalgae

Faculty Mentor

Adriane Jones

Start Date

23-11-2019 10:45 AM

End Date

23-11-2019 11:30 AM

Location

68

Session

poster 4

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Marine copepods traditionally feed on phytoplankton found in abundance throughout the world’s oceans. Phytoplankton can grow exponentially when there is sufficient light, nutrients, and lack of predators resulting in an overabundance of cells. The experiment was designed to observe the competition between three types of phytoplankton (Isochrysis sp, Chaetoceros sp, and Tetraselmis sp) in the presence or absence of a copepod predator (Tigriopus californicus). Isochrysis sp initially had the highest cell concentration compared to Chaetoceros sp and Tetraselmis sp to simulate the natural environment. The experiment ran for 6 days in a 12:12 light:dark period with a light intensity of 47μmol m-2s-1 at 21°C with ~20 copepods in flasks containing the copepod treatment. We counted cells with a hemocytometer and measured chlorophyll with a fluorometer. We hypothesize that Isochrysis sp would have the highest final cell concentration in both the treatment with copepods and without due to a high initial cell concentration. We found that chlorophyll was higher in the treatment without the copepod predators compared to the treatment with the copepods; this suggests that the copepods were eating the phytoplankton. We found that Isochrysis sp outcompeted both Tetraselmis sp and Chaetoceros sp in both the treatments with copepods and without. We also found that Isochrysis sp had a higher concentration in the copepod environment than the controlled environment and Tetraselmis sp had a lower concentration in the copepod environment in comparison to the control. This result indicates that the copepods may have preferred Tetraselmis sp and this may have reduced the competition with Isochrysis sp. Chaetoceros sp remained relatively constant in both environments. This study suggests that the addition of predators can reshape the food web by creating a possible advantage for some phytoplankton, and that there is also a possibility that copepods prefer certain phytoplankton over the others.

This document is currently not available here.

Share

COinS
 
Nov 23rd, 10:45 AM Nov 23rd, 11:30 AM

Feeding Selectivity of Marine Copepods on Three Microalgae

68

Marine copepods traditionally feed on phytoplankton found in abundance throughout the world’s oceans. Phytoplankton can grow exponentially when there is sufficient light, nutrients, and lack of predators resulting in an overabundance of cells. The experiment was designed to observe the competition between three types of phytoplankton (Isochrysis sp, Chaetoceros sp, and Tetraselmis sp) in the presence or absence of a copepod predator (Tigriopus californicus). Isochrysis sp initially had the highest cell concentration compared to Chaetoceros sp and Tetraselmis sp to simulate the natural environment. The experiment ran for 6 days in a 12:12 light:dark period with a light intensity of 47μmol m-2s-1 at 21°C with ~20 copepods in flasks containing the copepod treatment. We counted cells with a hemocytometer and measured chlorophyll with a fluorometer. We hypothesize that Isochrysis sp would have the highest final cell concentration in both the treatment with copepods and without due to a high initial cell concentration. We found that chlorophyll was higher in the treatment without the copepod predators compared to the treatment with the copepods; this suggests that the copepods were eating the phytoplankton. We found that Isochrysis sp outcompeted both Tetraselmis sp and Chaetoceros sp in both the treatments with copepods and without. We also found that Isochrysis sp had a higher concentration in the copepod environment than the controlled environment and Tetraselmis sp had a lower concentration in the copepod environment in comparison to the control. This result indicates that the copepods may have preferred Tetraselmis sp and this may have reduced the competition with Isochrysis sp. Chaetoceros sp remained relatively constant in both environments. This study suggests that the addition of predators can reshape the food web by creating a possible advantage for some phytoplankton, and that there is also a possibility that copepods prefer certain phytoplankton over the others.