After reading the paragraph below, answer the questions that follow.
Scientists from The National Centers for Coastal Ocean Science conducted a 6-year study on the effects of ocean temperature change on abundance of dominant intertidal species (barnacles and mussels). These organisms can outcompete other intertidal organisms for space (and therefore distribution and abundance). Suppose the scientists collected the following data on average intertidal zone temperatures (C°) and densities of mussel clumps and barnacle colonies (per square meter):
| Year | Avg. Annual Intertidal Zone Temperature (C°) | # Clumps Mussels/sq m | # Colonies Barnacles/sq m
|
| 2004 | 6° | 6 | 22 |
| 2005 | 6.7° | 5.5 | 19 |
| 2006 | 7.3° | 5 | 17 |
| 2007 | 7.8° | 4.75 | 16.5 |
| 2008 | 8.2° | 4.5 | 16 |
| 2009 | 8.5° | 4.5 | 16 |
| 2010 | 8.7° | 4.5 | 16 |
What can the scientists conclude from the data?
◦ An increase of 6°C is needed before the number of clumps of mussels decreases.
◦ An increase of 2.2°C from 2004 to 2008 reduces the density of barnacles and mussels by approximately 25%.
◦ Increasing annual ocean temperatures do not affect abundance of mussels or barnacles.
◦ If annual ocean temperatures were recorded for another three years, scientists would likely observe steady temperatures.
John Muir (right) with President Roosevelt at Yosemite National Park