Mailbag: Learn how to protect estuaries, ocean

Many ask, "What is an estuary?" The simplest answer is, "A place where fresh water and salt water meet." The tidal mouth of any river is an estuary. Local residents are lucky to have in their midst the largest remaining natural estuary in Southern California, the Back Bay, which stretches from Pacific Coast Highway to Jamboree Road near the Corona del Mar (73) Freeway. Many people come to enjoy the beautiful scenery, but few realize its ecological importance and the threats posed to it by human activities in the watershed.

The Back Bay is an important rest stop and/or winter home for birds migrating from Canada and Alaska, and a nesting area for summer migrants and year-round residents. The bay is also a spawning ground and nursery for many commercial and sports fish, including halibut and bass. The Back Bay, or Upper Bay, additionally plays a huge part in protecting the recreational boating infrastructure of the Lower Bay and the beaches of Newport Beach.

An area of 150 square miles of urban Orange County drains through the Upper Bay to the Lower Bay and then out to the ocean. Surface water runoff from this watershed brings with it trash and toxic chemicals and other less-obvious pollutants, including fertilizers, bacteria and other pathogens, and sediment. Excess fertilizer can cause algae blooms — proliferations of both large seaweed mats and microscopic plant plankton — which can eventually lead to oxygen depletion in the water causing marine life to die. High levels of bacteria in the water lead to health warnings and beach closures within the Upper and Lower Bays and along the coast impacting tourism and local recreational use. The Back Bay provides a natural treatment system for these pollutants, but it can easily be overwhelmed.

This year, we are pleased to showcase roughly 30 poster and multimedia exhibits presented by over 150 students from Costa Mesa High School, Santa Ana High School, Century High School and El Rancho High School. These impassioned students have been participating in a yearlong environmental stewardship program organized by the Newport Bay Conservancy and funded by the Sempra Energy Foundation Environmental Champions Initiative.