Laboratory Measures of Filtration by Freshwater Mussels - An Activity to Introduce Biology Students to an Increasingly Threatened Group of Organisms

Oct 15, 2026

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Filter-feeding aquatic organisms capture food particles from surrounding water, affecting turbidity and ecosystem dynamics. A laboratory exercise is described in which students measure how freshwater mussels influence water clarity by exposing mussels to a baker’s yeast solution and tracking turbidity changes over one to two hours. Miniature Secchi discs are used for observations, enabling hypothesis testing, data collection, and exploration of organism–environment interactions while highlighting biodiversity loss.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages6

Reading Time15 min

AccessFree to download

Abstract

Introduction

Filter feeding in aquatic ecosystems

Zebra mussel effects on Lake Erie

Background

Mussel anatomy

Laboratory Measures of Filtration by Freshwater Mussels: An Activity to Introduce Biology Students to an Increasingly Threatened Group of Organisms Michael J. Smith,1 Julie J. Shaffer,1,* Keith D. Koupal,2 and W. Wyatt Hoback1 1Department of Biology, University of Nebraska at Kearney, 2401 11th Ave., Kearney, Nebraska 68849, 2Nebraska Game and Parks Commission, 1617 1st Ave., Kearney, Nebraska 68847 *Corresponding Author: [shafferjj@unk.edu](shafferjj@unk.edu) Abstract: Many aquatic organisms survive by filter feeding from the surrounding water and capturing food particles. We developed a laboratory exercise that allows students to measure the effects of filtering by fresh water mussels on water turbidity. Mussels were acquired from Wards Scientific and exposed to a solution of baker’s yeast. Over a period of one to two hours, students measured changes in water clarity using miniature Secchi discs. The exercise has been used in a freshwater biology class at a state university. This exercise allows students to make hypotheses, gather data, and explore interactions between living organisms and their environment. Many North American species of freshwater mussels are threatened or endangered because of habitat changes and the introduction of exotic mussels. Therefore, students are also able to examine the potential effects of biodiversity loss in aquatic environments. Key words: freshwater mussel, macroinvertebrate, filter feeding, ecology INTRODUCTION Filter feeding organisms are a component of most aquatic ecosystems. The introduction of Dreissenid mussels, like the zebra mussels, into North American waters has elevated prominence of these organisms and their role in aquatic ecosystems. In spite of this increased awareness, little emphasis has been made in educational curriculum to demonstrate the potential impacts of filter feeders on aquatic ecosystems. Lake Erie, one of the Great Lakes of North America, is the eleventh largest freshwater lake in the world. With a maximum depth of 64 meters and a length of 388 kilometers, it contains more than 484 cubic kilometers of water (Great Lakes Information Network, 2012) . Lake Erie is the warmest of the Great Lakes and biologically the most productive. In the 1980s, Lake Erie was invaded by the zebra mussel, Dreissena polymorpha (Berkman et al., 1998; USGS, 2008) . This species is native to Russia and is relatively small, reaching a maximum of about 5 centimeters in length. In the United States, it reproduces rapidly and reaches densities of 70,000 per square meter. These mussels live and grow by filter feeding by which they pass water through their gills and collect food particles from the water. Today, it is estimated that zebra mussels filter the entire water volume of Lake Erie in less than one month. This filtration has removed many of the photosynthetic algal cells (phytoplankton), the aquatic producers that form the base of aquatic food chains, normally found in the lake. In the past twenty years, the zebra mussel has increased water clarity by up to 600 percent as a result of filtering out phytoplankton, (UW Seagrant Inst., 2005; USGS, 2009) . From this example, it is clear that filter feeding by aquatic organisms can have a large impact on aquatic food webs. A number of aquatic organisms, including microscopic rotifers, caddisfly larvae, paddlefish, and freshwater mussels rely on filter feeding to obtain energy. Among these filter feeding organisms, freshwater mussels live in the substrate of many freshwater streams and rivers, quietly filtering large volumes of water for most of their long lives, which in some cases can exceed 100 years (Bauer, 1992) . As they filter the water, they extract nutrients and other suspended particles, changing the properties of the water around them. Because they are long lived, stationary, and sensitive to changes in the water quality, mussels are commonly used as bioindicators of water ecosystem health (Angelo et al., 2

FAQs

What lab activity do students perform to study filtration by freshwater mussels?

Students expose freshwater mussels to a baker’s yeast solution and measure changes in water clarity over one to two hours using miniature Secchi discs.

How does filter feeding affect aquatic ecosystems, according to the text?

Filter feeding can remove photosynthetic particles such as phytoplankton, altering water turbidity and influencing food-web structure and ecosystem health.

Why are freshwater mussels important in biology education and ecology?

Freshwater mussels are long lived, sensitive to water quality, and used as bioindicators; the activity also lets students examine consequences of biodiversity loss in aquatic environments.

Oct 15, 2026

Upload by Aldword