Examining the effects of different diets and Salinities on Tigriopus californicus copepods population growth

Abstract

The coastal oceans are subject to climate impacts leading to sea level rise, increases in the frequency and intensity of storms, and increased precipitation. These events can lead to a rise in the amount of fresh water entering coastal ecosystems from runoff or rainfall, which cause decreases in ocean salinity. Understanding marine food web dynamics requires an understanding of how species interactions will respond to environmental changes of this kind. Sea urchins are key members of nearshore food webs and may help to link food availability between shallow and deep zones along coastal areas. Urchins’ inefficient digestion, means that their feces may possess large amounts of available nutrients, which other organisms can use as a viable food source. I studied population growth of T. californicus copepods in both low salinity and normal seawater environments, and with diets of either fresh Ulva or urchin fecal Ulva. I also examined the caloric content of these different diets. Results show that both diet and salinity significantly affected population growth, low salinity is the better environment, and fresh Ulva is the better diet