What do Steller sea lions, snowflakes, and amphipods have
in common? They are the latest topics featured in the Bridge’s
Data Tips of the Month, activities that will challenge your
students with scientific data and critical thinking exercises.
Here’s a quick look at the some of the science and issues
surrounding these three topics. For the complete classroom
activity, visit the Bridge’s Data Tip Archives.
A Stellar Animal - December 2001
Steller sea lions, the largest of the eared seals, are
found along the north Pacific Rim from California to Japan.
These sea lions are divided into two distinct stocks that
are split at 144° W longitude. These two stocks differ not
only genetically but also in the stability of their population.
Both groups experienced a dramatic drop in numbers in the
1970s and were provided federal protection in 1972 with
the Marine Mammal Protection Act. The eastern stock’s situation
has improved, but the stock west of 144° W longitude continues
to decline despite being designated as a threatened species
in 1990 and as an endangered species since 1997. Is the
driving factor competition with commercial fisheries for
food, as many believe, or is there more to the story?
Winder Wonderland - January 2002
Snow, to those in the snow belt states, may seem like no
day at the beach, but in reality it's far closer than you
may think. In fact, that knee-deep snow that upstate New
Yorkers trudged through last Christmas was, not so long
ago, ocean water in which beach lovers were wading. All
of the earth's water is directly connected through the water
cycle. Learn some of the water chemistry behind snow, and
then take a look at this season’s snowfall.
More Than Mud - February 2002
When thinking of benthic habitats, sand, mud and a few
worms probably come to mind. But there are many different
types of benthic habitats and organisms, from a complex
of mud tunnels housing worms and clams to oyster reefs where
invertebrates and fish hide in nooks and crannies. Benthic
communities are vital to the ecosystem at large, supplying
food and habitat for many organisms and improving water
quality through their filter feeders. But benthic communities
are also one of the aquatic areas most vulnerable to human-induced
problems, especially eutrophication and contamination. Learn
how scientists use amphipods, a common Chesapeake Bay benthic
organism, as an indicator species to help identify polluted
Submitted by: Johnette D. Bosarge
National Marine Educators Association