Abstract
Tide pools are diverse and volatile habitats. They are essentially mini ecosystems within a larger ecosystem. This study looked at six randomly chosen tide pools in the upper intertidal zone in Nahant, MA at Canoe Beach. It studied the abiotic factors of salinity and pH and its affect on littorina density in each tide pools. Data was taken over the course of two months for three days. The data was calculated using ANOVA. P-values were significant for both salinity and pH in some tide pools while insignificant in others. In general it was concluded that salinity and pH may have greater effects on littorina density in one tide pool over another due to other abiotic and biotic factors present within them.
Introduction to Tide Pools
The intertidal zone is a difficult place to habituate. Four times a day during high and low tide, drastic environmental changes occur. During the low tide organisms are exposed to desiccation and predators, during high tide they are submerged in water and are subjected to waves of varying intensity (Bertness).
Within the intertidal zone is a even more extreme habitat; tide pools. A tide pool within a meter from another tide pool can foster a community of diverse organisms while the other can contain only barren rocks. This is due to the differences between biotic and abiotic factors in each tide pools. Biotic factors include; competition and predation (Nielsen). Abiotic factors include temperature, dissolved oxygen, PH, location, and salinity (Bertness).
Both abiotic and biotic factors affect the diversity of organisms within a tide pool. In this study we seek to understand the relationship between the number of littorina present in a pool and its salinity and ph levels.
Salinity
The term salinity pertains to the level of salt in one kilogram of water. The average salinity for the ocean is 35 ppm while freshwater is only at 0.5. Salinity is an important factor to because drastic changes in salinity may contribute to lower species diversity. This lowered diversity is often due to osmosis. Osmosis is the movement of water across a membrane to equalize the salt levels on both sides of a membrane. If an organism is present in areas of high salinity or low salinity they can undergo lyses or plasmolyzed both deadly conditions
PH levels
The pH level measures the hydrogen ion concentration in the water, the average ph for water is 7. A ph level of 7(+5) is average for most organisms. It is important for ph levels to stay within that region for it becomes to low enzymes and proteins denature. This will cause eventually death in an organism.