Baseline Study of Springer Lake

And Wetland

Cindy Moulder, Sam Mason, Shawn Hopkins

EA2000/2001

Abstract

This study concerns the water analysis of lake, bog and wetland waters on the Springer Lake property owned by Capitol Land Trust. Water samples were taken over a 5-month period and analyzed using ion chromatography and atomic absorption spectrometry. Physical observations include plant identification and evidence of fauna. The studies show an acidic environment with low concentrations of nutrients, typical of a sphagnum moss bog and wetland system.

Introduction

The Springer Lake properties, owned by Capitol Land Trust, lie south of Tumwater in Thurston County (SW¹/₄, SE¹/₄, T/17N-R/02W-S/24), State of Washington, (Map 1, Appendix B). Mild, wet winters and dry summers characterize this area. The Springer Lake properties include a lake and bog, a wetland, intermittent streams and a lowland forest. The major water body, Springer Lake has an area of approximately 5.5 acres. The eastern edge of the lake is a sphagnum bog drained by an intermittent north flowing stream. Southeast of the sphagnum bog is an emergent wetland drained by a northeast flowing stream. The Olympia Airport, which is 3 miles northeast of the lake, has an average rainfall of 53.51 inches a year (Noble and Wallace 1966). The geology of this area of Thurston County is glacial in origin. Springer Lake and the wetland are both kettle holes made by the melting of buried ice left behind by the receding Vashon Glacier, approximately 13,000 years ago (Noble and Wallace 1966). Precipitation and groundwater are the primary sources of water for the lake and wetland. Of some importance are the presence of beaver dams, several of which are in place on the outlet stream of the lake and sphagnum bog and the outlet stream of the wetland. The dams appear to have an important effect on the water level of the lake and wetland.

The purpose of this study is to provide Capitol Land Trust with baseline data describing the waters of Springer Lake, the bog, and the wetland. This data will be included in the Trust’s database, along with a map showing sampling locations (Map 2, Appendix B), and a list of plants identified on the property (Appendix C). Water chemistry and properties that are useful to Capitol Land Trust include pH, the concentrations of major constituents; chloride, nitrite, nitrate, phosphate, sulfate, calcium, magnesium, sodium, potassium and alkalinity; and general biological observations made throughout the course of the study.

Methods

Water samples were taken from four locations (Map 1, Appendix B). The sampling sites were chosen to make comparisons within the two groups of water; the lake and sphagnum moss bog and the wetland and its outlet stream. The sample sites will be referred to as lake, bog, wetland and stream. Physical observations taken at the sampling location include water temperature and the change in water level of the bog and lake. pH measurements were recorded in the lab. Alkalinity titrations were performed before filtering the samples following Standard Methods 2320 (Clesceri et al.).

Anion concentrations were determined by Ion Chromatography following Standard Method 4110 (Clesceri et al.) using a Dionex Ion Chromatograph 2020 Advanced Chromatography Module. Data was collected with Vernier’s Logger Pro data collection software. Anions included in the analysis were: Chloride (Cl^-), Nitrite (NO₂^-- N), Nitrate (NO₃^-- N), Phosphate (PO₄^- - P), and Sulfate (SO₄^-2).

Cation concentrations were determined using a Perkin-Elmer Atomic Absorption Spectrometer Model 305B following Standard Method 3111-B (Clesceri e al.). Cations included in the analysis were Sodium (Na⁺), Potassium (K⁺), Magnesium (Mg⁺²) and Calcium (Ca⁺²). Samples were treated with 2000 ppm Lanthanum and 1000 ppm Cesium to suppress interferences. Concentrations were determined using a non-linear standard curve matrix in Microsoft Excel.

Results

The results of our analysis for the lake, sphagnum moss bog, wetland, and stream are summarized in Table 1. For complete data, refer to tables in Appendix A. Our analysis showed an acidic environment with varied pH. The pH values are lower in the bog than anywhere else on the property. These levels are lower than the average pH of rainwater, 5.6 (Crum 1988). The rest of the water on the property is neutral, with a pH of about 6.2. Nitrite, nitrate and phosphate levels were below the detection limit of the Dionex I.C 2020. Chloride and sulfate were present in low concentrations in all of our analyses. Potassium levels were low. Calcium was highest in the stream, where we also found our highest alkalinity levels. Alkalinity concentrations were lowest in the bog, and highest in the stream that drains the wetland. Average alkalinity for Thurston County groundwater is 68 ppm (Noble and Wallace 1966) .

Table 1. Summary of water analysis at the Springer Lake property.

Concentrations expressed in ppm	Site 1: Lake	Site 2 : Bog	Site 3: Wetland	Site 4: Stream
Anions
Chloride	2.8	2.7	3.4	3.0
Nitrite (N)	0.0	0.0	0.0	0.0
Nitrate (N)	0.0	0.0	0.0	0.0
Phosphate (P)	0.0	0.0	0.0	0.0
Sulfate	2.9	1.3	3.1	2.1
Alkalinity	10.7	8.0	12.8	13.6
Cations
Calcium	1.9	2.9	2.7	3.1
Magnesium	1.1	0.7	1.1	1.2
Potassium	0.8	0.7	0.8	0.9
Sodium	2.7	1.9	2.4	3.0
pH	6.3	4.6	6.0	6.2

Discussion

The Springer Lake property has been set aside for its conservation features. These features include a lowland forest, an emergent wetland, a kettle lake, and a floating mat sphagnum moss bog (Map 2, Appendix B). Together these features provide habitat for mammals, birds, amphibians, and insects. Rare plants can be found growing on nurse logs floating in the lake, and the bog’s unique water chemistry limits the types of plants that can survive there.

Nutrient levels in the system are low. Our study did not detect nitrite or nitrate. This does not indicate an absence of nitrogen, because, “About 40% of the total nitrogen is held in organic compounds that require chemical action for conversion to soluble forms. Such conversions depend on decay organisms that are, however, not very active under conditions of acidity” (Crum 1988). This is true of the bog, where even though the lake and the bog are the same body of water, statistical analysis shows the bog’s average pH of 4.6 is significantly more acidic than the lake’s (t = 4.16, df = 5, p=0.004). It is common for water in bogs to be acidic, due to the dominance of Sphagnum spp. According to Westlake and others, “the high acidity in the raised bogs is caused by Sphagnum plants, living or dead, acting as cation exchange materials with the surrounding water containing dilute cations….These cation exchange processes enable both Sphagnum and the higher plants of bogs to use all mineral ions, with maximum efficiency in their competition with other plants in a nutrient-poor environment” (Westlake 1998). These plants exchange cations such as K⁺, Na⁺,Ca²⁺, and Mg²⁺ with H⁺, and due to a lack of decay, these cations are not released when the plant dies. The build up of H⁺ in the water causes the acidity and results in a low pH.

The cation concentrations we observed were lower than average Thurston County groundwater. For example, the average calcium ion concentration in Thurston County groundwater is 16 ppm (Noble and Wallace 1966) compared to 3 ppm in the bog and wetland. On April 12, we witnessed our highest alkalinity, (as calcium carbonate), of 12 ppm. The water temperature was 5 degrees Celsius, the coldest day of our study. According to Howard Crum, “ A gain or loss of carbon dioxide, because of temperature changes or biological events, shifts the carbonate-bicarbonate equilibrium” (1988). Cooler temperatures allow more carbon dioxide to be dissolved into the water, increasing the carbonic acid concentrations, and therefore the concentration of bicarbonate ions.

Calcium availability is an important limiting factor for plants survival in the system. Plants need calcium for cell wall formation, and concentration that are too low may inhibit root growth. Sphagnum species, however, “require a relatively low concentration of calcium, and in fact most species are unable to tolerate the combined effect of high acidity and high calcium” (Crum 1988). Because the water contains low levels of nutrients, rare plants, such as the Sundew (Drosera rotundifolia), that thrive in a low nutrient environment are present.

This property teems with life, a good indication of the health of the environment. Species of mammals, birds, amphibians, and insects have been observed. Evidence of beaver activity can be found throughout the property. Chewed trees, dammed streams, small trails leading to the water’s edge, and a beaver lodge are visible. Western Hemlock trees around the perimeter of the bog have turned brittle and died. An unproven but plausible cause is a beaver dam flooding the area where the Hemlocks grew. Owls and woodpeckers have been heard in the canopy, and ducks and geese have been seen in the water. Small frogs swim in the water that bubbles up from the ground near the trail. The water also harbors insect larvae, and the drone of buzzing insects gets louder as the season changes.

The purpose of this study was to provide Capitol Land Trust with baseline data of Springer Lake to use in their stewardship of the land. The study shows an acidic bog with low levels of nutrients throughout the water in the system. The property provides habitat for animals and plants that are especially adapted to this unique environment. The types of plants, especially sphagnum species, create an environment that supports rare species and limits introduction of other organisms.

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