Community Environmental Health Laboratory Eelgrass Monitoring 2013-Present

Study Extent

About this project Eelgrass (Zostera marina), a species vital to the health of marine ecosystems is declining across the world. Help researchers track eelgrass populations. Add your reports of eelgrass presence and disappearance to help researchers understand this ecologically important underwater flowering plant! Project goal Help researchers gain a better understanding of eelgrass What participants do: Share observations of eelgrass' presence and disappearance in your local waters.

Sampling

What we need to know: Is eelgrass growing in waters near you, or has it disappeared? Do you have photos? (optional) What other background information do you have that might be useful? What is Eelgrass? Eelgrass, or Zostera Marina, is an aquatic grass-like flowering plant that grows mainly in the subtidal zone in shallow coastal waters. Some plants produce tiny flowers in a “spathe”, pollinate under water, and spread by seeds leading to great genetic diversity among the plants. Others spread vegetatively by sending up lateral clonal shoots connected by “rhizomes”, runners that act to anchor the plant to the mud. Why is eelgrass important? Eelgrass is essential habitat for many commercial fish species, and its decline is correlated with the loss of fish stocks and diversity. The leaves are buoyant, rising into the water column, providing an excellent place for juvenile shellfish to attach to at a crucial stage in their life cycles when they need to feed on suspended plankton. By photosynthesizing under water, the plants increase dissolved oxygen. The root structure of eelgrass stabilizes and oxygenates the mud or sandy sediments, allowing invertebrates to settle. Identifying Eelgrass: Eelgrass grows mostly in the subtidal zone, but is sometimes exposed at low tide. Its leaves float up when submerged but lay flat when out of the water, and sometimes especially long blades float at the surface. People often confuse eelgrass with salt marsh grass, Spartina, but unlike eelgrass, that plant is rigid, standing upright out of the water, and is often visible extending above the water at high tide. Some identifying features of eelgrass to look for: Eelgrass leaves are thin, flattened blades. Inner leaves are new growth, older outer leaves begin to decay and fall off throughout the season. Blade length varies depending partially on water depth. The lower portion of the stem is surrounded by a thin sheath. Flowering plants have a spathe with male and female flowers, or may hold ovoid seeds. Flowering plants also have nearly yellow stalks (not all are flowering) The plants are anchored in the sediment with rhizomes, or runners from which other shoots and roots grow.

Method steps

1. What we need to know: Is eelgrass growing in waters near you, or has it disappeared? Do you have photos? (optional) What other background information do you have that might be useful? What is Eelgrass? Eelgrass, or Zostera Marina, is an aquatic grass-like flowering plant that grows mainly in the subtidal zone in shallow coastal waters. Some plants produce tiny flowers in a “spathe”, pollinate under water, and spread by seeds leading to great genetic diversity among the plants. Others spread vegetatively by sending up lateral clonal shoots connected by “rhizomes”, runners that act to anchor the plant to the mud. Why is eelgrass important? Eelgrass is essential habitat for many commercial fish species, and its decline is correlated with the loss of fish stocks and diversity. The leaves are buoyant, rising into the water column, providing an excellent place for juvenile shellfish to attach to at a crucial stage in their life cycles when they need to feed on suspended plankton. By photosynthesizing under water, the plants increase dissolved oxygen. The root structure of eelgrass stabilizes and oxygenates the mud or sandy sediments, allowing invertebrates to settle. Identifying Eelgrass: Eelgrass grows mostly in the subtidal zone, but is sometimes exposed at low tide. Its leaves float up when submerged but lay flat when out of the water, and sometimes especially long blades float at the surface. People often confuse eelgrass with salt marsh grass, Spartina, but unlike eelgrass, that plant is rigid, standing upright out of the water, and is often visible extending above the water at high tide. Some identifying features of eelgrass to look for: Eelgrass leaves are thin, flattened blades. Inner leaves are new growth, older outer leaves begin to decay and fall off throughout the season. Blade length varies depending partially on water depth. The lower portion of the stem is surrounded by a thin sheath. Flowering plants have a spathe with male and female flowers, or may hold ovoid seeds. Flowering plants also have nearly yellow stalks (not all are flowering) The plants are anchored in the sediment with rhizomes, or runners from which other shoots and roots grow.

Primarily collected in Mount Desert Island, Maine