Nearshore and benthic (bottom-dwelling) organisms are good gauges of change in the environment. Many are sedentary, sensitive to change, and easy to access for study. Scientists are usually more able to discover the source of change in this kind of habitat. Once those sources are found, they can identify and compare changes that are natural from those that are man-made. Click the image below to discover the different zones of the nearshore ecosystem.
The Nearshore Ecosystems team collects data in the tidal areas. Researchers are focused on learning about the variety and abundance of the species living at sites in Prince William Sound, the outer Kenai Peninsula, and Lower Cook Inlet.
This data will help scientists find answers for questions like:
• Is the nearshore environment changing significantly from year to year?
• Have resources in this environment recovered from the 1989 oil spill? If not, are there reasons other than the oil spill?
• Are changes in offshore conditions also causing changes in the nearshore habitats?
This project focuses on organisms that are considered crucial to the nearshore ecosystem’s health. One such key species is the black oystercatcher. These shorebirds are good candidates for monitoring projects because they have a long lifespan.
Over that lifetime, the oystercatcher lives in and depends upon intertidal habitats. This is where they mate, nest, and raise their young. Even though black oystercatchers aren’t benthic animals, they eat a diet of creatures that are. Their menu of mussels, limpets, and chitons are easily effected by changes in the environment. If oystercatchers aren’t healthy, it probably means that something significant has happened to the shellfish that they eat.
Click on the image below to learn more about the black oystercatcher, a critical species of the Nearshore Benthic Systems in the Gulf of Alaska project.
Click the audio icon to hear the call of the black oystercatcher.
Scientists, like the National Park Service’s Heather Coletti, are trying to address the following questions:
• Are the numbers of black oystercatcher nests changing from year to year?
• Is the number of eggs or chicks in each nest changing?
• Are chicks supplied with the same variety and amount of food each year?
• Does this data change from one location to another?
Heather and her team monitor the habitat of black oystercatchers using a variety of methods, including the use of shoreline transects to survey nest sites and sample prey remains at oystercatcher nesting sites.
VIDEO: Monitoring Nearshore Systems
Heather Coletti describes her work studying black oystercatchers for the nearshore systems component of Gulf Watch Alaska. (1:50)
The nearshore is that interface between the terrestrial system – land – and the oceans. And there are several influences from the ocean that meet at the nearshore and then we have anthropogenic and natural influences from the terrestrial, and in some heavily populated areas that’s pollution and runoff, and how the nearshore really is affected by all those influences. And it’s essentially where the densest human populations live, along the coasts.
Our program is essentially monitoring the nearshore food web. So we start out at the sea grasses and algae, which are the primary producers of that system. And then we look at invertebrates – benthic invertebrates – whether it’s mussels, clams, limpets… And then we have surveys for higher trophic level predators, like your sea ducks, sea otters, sea stars.
We monitor oystercatchers, which are a pretty charismatic shorebird that is essentially confined to the nearshore and the intertidal. They feed exclusively in the intertidal on benthic invertebrates. So that’s your mussels, your limpets, that’s their two primary food sources, but they’ll eat some barnacles and some worms. So we have several aspects of their biology that we are monitoring.
The goal of any monitoring program is to look at change over time and understand change over time, what’s driving it and if there’s any way to predict what those outcomes may be. That’s ultimately the goal and we are in our first few years of monitoring, and right now looking at what the natural variation in these systems is like. That hasn’t been fully documented yet.
Who is watching the Gulf?
Abundance (n): the quantity or amount of something
Benthic (adj): pertaining to the seafloor and the organisms that live there
Data (n): values for something measured
Density (n): the number of inhabitants per unit of area
Distribution (n): the way in which something is spread over an area
Intertidal (n): the benthic shore area between the extreme reaches of high and low tides
Nearshore (n): the marine zone that extends from the high tide line to depths of about 20 meters
Organism (n): an individual life form
Prey (n): an animal taken by predators as food
Riparian zone (n): the area of land next to a lake, river, stream, or wetland
Subtidal (n): the benthic area below low tide that is covered by water most of the time and exposed briefly during extreme low tides
Tide (n): the alternate rising and falling of the sea at a particular place, due to the gravitional attraction of the moon and sun
Transect (n): a path along which scientists count animal populations and plant distributions