Quartermaster Harbor seems to be on everybody’s priority list.

The National Audubon Society designated Quartermaster Harbor an Important Bird Area in 2001, in part, because of the high Western grebe populations. Christmas bird counts show a steady decline — from 1,520 grebes 10 years ago to only 17 observed last year.

The harbor is also part of the state-established Maury Island Aquatic Reserve, the goals of which are to conserve the habitats and species that make the site unique and to support traditional recreational, cultural and commercial uses of the area. And parts of the shoreline have been designated a Marine Recovery Area (MRA) by King County. Much of the driving force behind that designation are the valuable geoduck beds on the western shores of the harbor, which are closed to commercial harvest due to contamination from failing septic systems.

All of this interest in Quartermaster Harbor, and in the role it plays in the overall health of central Puget Sound, is coming at the same time that scientists have discovered some disturbing trends — low oxygen levels in the bay that could prove lethal to some animals.

Over the last three years, King County has conducted monthly monitoring of near-bottom waters in Quartermaster Harbor at two stations, one near Burton and another near Dockton. The general pattern in the data shows that oxygen levels at both sites have hit levels between 3-5 milligrams/liter (mg/l) in late summer or early fall. The state water quality standard for the harbor is 7mg/l.

Oxygen levels below 5 mg/l stress many aquatic organisms, and levels that remain below 2 mg/l for a few hours can cause large fish kills.

Fast-moving fish will swim to the surface where oxygen levels are higher, sometimes flaring their gills and gasping for breath, but invertebrates like clams and worms may be out of luck.

Lack of oxygen in the water column has caused dead zones in Hood Canal that have garnered headlines over the past few years; researchers are wondering whether similar conditions could develop in Quartermaster Harbor.

With all of this interest and attention, little wonder that the U.S. Environmental Protection Agency has funded a new four-year study to investigate the causes of low oxygen levels in Quartermaster Harbor. Researchers will focus on the role nitrogen plays in causing these “hypoxic” events. The Quartermaster Harbor Nitrogen Management Study — to be conducted by county and state scientists as well as scientists from the University of Washington-Tacoma — is designed to evaluate the role nitrogen plays in lowering the oxygen levels in the harbor.

Nitrogen is a nutrient that can spur algal blooms in marine waters. Oxygen is consumed as the algae decays. The intent of the new study is to look at all of the relative inputs of nitrogen into Quartermaster Harbor from the entire drainage area, which includes about 40 percent of the Island. Possible sources include fertilizers, manure, atmospheric deposition, failing septic systems and nitrogen-fixing vegetation, even changes in oceanic waters. Though our home lies high above Dockton, we are in the Quartermaster Harbor watershed, as are all the folks who live in the Judd Creek, Fisher Creek and Mileta creek drainages. No longer are only shorefront property owners asked to care for Quartermaster Harbor.

For example, Mileta Creek on the western shore of Maury Island has unusually high winter nitrate levels, three times as high as Judd Creek. To my knowledge, nobody has asked how much fertilizer is used at the Vashon Island Golf & Country Club’s golf course, which is part of the Mileta Creek drainage. Or, maybe the soils on Maury Island simply leach more nitrogen.

Initial monitoring of Judd Creek showed fecal coliform levels over 1,400 organisms per 100 milliliters in September 2007. The standard for approved shellfish-growing waters is a geometric mean not to exceed 14 organisms per 100 milliliters. Clearly, not every fecal coliform bacteria and nitrogen atom in Quartermaster Harbor originated on a shorefront lot.

The point is, we are all in this together. I am not advocating that we ignore failing septic systems on the beach. For now, it makes sense to move forward with some affordable solutions. Composting or incinerating toilets can keep black water (sewage) out of the Sound. Planting native conifers can take up nitrogen. And, as co-managers of an aquatic reserve, we should begin thinking about when habitat needs of aquatic species outweigh the “traditional recreational, cultural, and commercial uses of the area.”

— Susie Kalhorn is an environmental educator.

King County scientists will give a public presentation about the Quartermaster Harbor nitrogen loading study at 7 p.m. Thursday, Nov. 19, at the Vashon Maury Island Land Trust, 10014 Bank Road S.W., Vashon.