CLUES FROM THE LANDSCAPE
As scientists gather clues from the sea otters
and the food web
about what impacts are facing the Pacific nearshore ecosystem, they must also examine the potential causes of those impacts.
At this point, the lens of investigation zooms out. Instead of focusing on detailed process and measuring increments, project scientists must take a step back and observe the entire coastal ecosystem -- back on the terrestrial landscape and on our coastal rivers, forests and cities.
The health of our nearshore ecosystem is intricately linked with what happens on land. Rivers, creeks and even runoff from rainwater connect our terrestrial landscape with our marine depths in a single, continuous nexus. So project scientists must consider clues away from the ocean as well.
Land Use Change and Fires
Sea otters can be found in many locations stretching from California to Alaska. And while the underwater habitats of all these different locations may be somewhat similar, the terrestrial landscapes can be drastically different -- possibly offering clues to why some sea otter populations are doing well, and others are not.
Some coastlines are dotted with uninhabited forests with little land use
by humans, while others are bustling towns or agricultural plains which inevitably introduce unnatural chemicals and excess materials into our air and water. Some coasts are prone to wildfires
that generate ash and air pollution, while others rarely experience them. Of course, our terrestrial landscape changes over the years as well, as some human developments grow in size, while some rangelands are returned to natural states.
Examining huge areas of the Earth's surface and recording their changes over time? That sounds like a job for our remote sensing
space satellites again, which we used to study clues from the food web
. Indeed, project scientists are also looking at satellite images of terrestrial landscapes adjacent to waters where sea otters populations are found.
It would be a poor assumption to say that all human land uses are automatically bad for the nearshore ecosystem and all natural lands are harmless. Project scientists must objectively compare the patterns of change on land with the patterns of change in sea otters and the sea -- if they are to clue into any connections that might exist between the health of our Pacific nearshore waters and our terrestrial landscapes.
To understand how a terrestrial landscape might be influencing the health of its adjacent nearshore waters, project scientists must also understand that landscape's watershed and what materials are being transported by it.
Like a river flows / surely to the sea
, Elvis Presley once sang
. That pretty much describes how watersheds work. A watershed
defines the area of land within which all waters can drain toward a single point, either into another watershed or into the sea. Think of watersheds as giant bathtubs or basins -- if you pour some water along the higher points and rims of that basin, it will follow gravity and flow along the lowest points.
In your tub, water ends up in your drain. On the landscape, rainwater and creeks flow down from higher ground toward lower ground, combining into a single river and moving along until eventually the waters can't get any lower -- sea level -- and into the sea and our nearshore ecosystem.
Project scientists want to know if the materials carried downstream in our watershed could be affecting the nearshore ecosystem's health. To date, scientists have identified a number of land-based diseases, parasites
in shellfish and in sea otters -- often leading to harmful results. Studying our watersheds through water sample analysis and remote sensing will help scientists understand where in the landscape these diseases and toxins are originating from, and whether human activities like nutrient fertilizing or improper sewage treatment is contributing to the cause.
As project scientists compare the land use and watershed patterns among all the different nearshore waters from California to Alaska, they must also consider any clues from the natural differences among the locations.
For one, California, Washington, British Columbia and Alaska are all at very different latitudes. Natural factors like temperature, weather, ocean currents, terrestrial vegetation and others can be very different from the southern end to the northern end of our Pacific coastline. As they compare and contrast the clues from otters, the food web, terrestrial landscapes and watersheds, scientists must explore which effects are simply due to natural variation.
Explore more clues below, or meet the research team: