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Aquatic and Marine Ecosystems—Lesson 1: Aquatic and Marine Ecosystem Connections1

Karen Blyler and Joy Jordan 2

For the full version of this document, view the PDF here.

To access other sections and lessons of the Aquatic and Marine Ecosystems: Leader's Activity Guide, view the EDIS topic page here.

Lesson 1


To become familiar with and differentiate between basic physical and biological factors common to all aquatic/marine systems.


Here are some learning activities and suggested ways to implement the activities in Lesson 1.

1.1 Discover and understand Florida's many diverse aquatic/marine ecosystems with WHAT'S AN ECOSYSTEM?

1.2 Learn how one critical factor affects different ecosystem communities using SALT OR NO SALT, WHAT'S THE DIFFERENCE?

1.3 Identify the stages of the hydrologic cycle with WATER BASICS.


1.5 AQUATIC FOOD CHAINS, and 1.6 FOOD WEBS: STRINGS ATTACHED to discover the relationships and interdependence between the living and non-living parts of ecosystems.

1.7 Discover some different stages of AQUATIC SUCCESSION.

1.8 Complete AQUATIC / MARINE VALUES to identify the many ways aquatic/marine ecosystems are important to humans.


After completing each activity in this lesson, help youth reflect on what they have learned with these questions:

  • How many different aquatic/marine ecosystems can you name?

Swamps, marshes, bogs, rivers, streams, springs, lakes, ponds, bays, beaches, estuaries, mangroves, gulfs, oceans, coral reefs.

  • What are four stages of the hydrologic cycle?

Precipitation, transpiration, evaporation, and condensation.

  • Define "abiotic factor" and list some examples.

A nonliving part of an ecosystem. Some examples are water temperature, depth, salinity, wave motion, and sunlight.

  • What is a food chain?

The transfer of energy from the sun to primary producers to consumers.

  • What happens if one component of a food chain is removed?

The other components may also be affected.


Help youth to apply what they have learned to their daily lives.

  • What human values are associated with aquatic/marine ecosystems?

Aquatic/marine ecosystems are important resources for many reasons including; economic values (food and transportation), aesthetic values (beauty and serenity), recreation values (fishing and boating), education values (marine science and botany), and health values (nutrition and drinking water).

  • How does human activity affect these aquatic/marine ecosystems?

Marine debris, storm water runoff, pollution, dams, and coastal development are some examples of human impacts on aquatic/marine ecosystems.

  • How can we conserve our aquatic/marine ecosystems?

By taking responsibility for our actions on aquatic/marine ecosystems to ensure our continued use and enjoyment, as well as for the survival of all species that depend on these ecosystems.

Background Basics

Water . . . Earth's unique and precious resource. Earth is the only planet in our solar system with the necessary atmospheric conditions to allow water to exist as we know it. Water is essential to all life on earth. Plants and animals are composed mostly of water. Human bodies are made up of 95% water. Humans may survive for long periods of time without food, but can survive no longer than a few days without water. We depend on water not only for the physical makeup of our bodies, but also for the environment it provides while moving through its three states. Water is the only substance found on earth that occurs naturally in three forms, solid, liquid, and vapor.

The Water Cycle

The water cycle is a familiar, yet a dynamic mechanism which continually moves throughout all ecosystems. It is a natural process which has no beginning or end. The cycle is driven by energy from the sun that causes the evaporation of water from land and water surfaces and transpiration of water from plants. Transpiration occurs when water absorbed by plant roots is drawn through the body of a plant and then evaporates from the surface of leaves and stems. As water vapor rises, it cools, and condenses into clouds. When the water once again falls to the Earth's surface as rain, snow, sleet, and hail, it is called precipitation. Once on the surface, the water may immediately evaporate back into the atmosphere or run off into streams, rivers, and other water bodies. Surface water may also infiltrate the ground where it will eventually reenter the cycle through groundwater discharge or transpiration by plants.

In Florida, precipitation falls almost exclusively as rain, with occasional snow and hail. The dry season extends from October through May, and the wet season from June through September. Convective rains or thunderstorms occur in late afternoon in the spring and summer. Tropical low pressure storms from the Atlantic Ocean and the Caribbean Sea occur from late summer into early autumn. Fronts from the North American continent sweep the state during the fall, winter, and early spring. Tropical storms and hurricanes may cause heavy rainfall during the wet season. Seasonal fluctuations in precipitation can greatly affect water resources.

Surface runoff is the water which directly flows across the land into streams, rivers, or lakes. As water moves over the land, it may be seen as sheet runoff, or rills and gullies. Sheet runoff can be easily seen on a parking lot, whereas rills and gullies may be best observed on a slope of bare soil. Water that does not run off infiltrates (soaks into) the ground. When it travels through the soil, it may be absorbed (taken up) by the root systems of plants and used for their physiological processes.

Water not used by plants either adheres to soil particles or continues to move through the soil in all directions. Eventually the water will reach bedrock or a totally saturated zone in the soil. The top of this zone is called the water table. Water below the water table is called groundwater. Where the water table reaches the ground surface, it may appear as a spring or it may move directly into a flowing stream. This concept is important because without the subsurface movement of water and subsequent recharge of surface water, many streams would not flow between precipitation events. Subsurface drainage may be fast or very slow depending on soil types, depth to bedrock, slope and other climatic and geologic factors.

Water that reaches bedrock can move through cracks and fissures in the rock structure. It may move slowly through the rock formation or remain in place for hundreds of thousands of years. A rock formation that holds vast amounts of water is called an aquifer, a term derived from the two Latin words "aqua," meaning water, and "ferre," meaning to bear or carry. In Florida, we have the huge and deep Floridan Aquifer and the more shallow Biscayne Aquifer, which together provide nearly 90 percent of the state's drinking water, irrigation water, recreational water, and waste disposal water (Myers and Ewell, 1990).

People withdraw water from groundwater and surface water resources for their daily domestic and economic needs. These uses of water can greatly affect the natural recharge of stream flows and groundwater. Development projects that involve the removal of natural land areas and paving over large soil surface areas may have adverse environmental impacts on soil erosion, stream flow levels, and the natural recharge of groundwater resources. Our utilization of this resource is a necessity, and with careful planning, adverse environmental impacts resulting from our interruption of the natural water cycle can be minimized.



All plants and animals require water, but in varying amounts. The amount of water and other nonliving factors in an area determine the types of plants and animals that can exist there. A community is all of the living things in a given area. The community and the nonliving environment function together as an ecosystem. Ecosystems are made up of both the living, biotic component, and the nonliving, abiotic, component. The abiotic component of an area largely determines what types of life forms can exist there. Water is one abiotic component, but there are many others such as soil type, elevation, temperature, salinity, etc.

Figure 1. One of many different ecosystems in Florida
Figure 1.  One of many different ecosystems in Florida
Credit: Photos taken by 4-H members

Florida has many very diverse types of ecosystems. One of the reasons for this diversity is that the northern part of the state is situated in the temperate zone and the southern part of Florida extends into the subtropics. Although the State does not have diverse topography, changes in elevation have a significant effect on Florida's ecosystems. In the higher elevations are pine flatwoods, dry prairies, scrub and high pine habitats, and temperate hardwood forests. In south Florida, rockland ecosystems consist of pinelands and tropical hardwood hammocks. In the lower areas are swamps and freshwater marshes. Along the coast, are dunes and maritime forests. Florida has approximately 7700 lakes, more than 1700 rivers, and over 300 artesian springs (Myers and Ewell, 1990). Most of the larger rivers discharge at the oceans, emptying into estuaries, salt marshes, and mangroves. Florida's coastal areas and marine ecosystems are also quite diverse, from the beach dune community to several different offshore reef communities.

Learn More

To read more of the Background Basics section and the activities for Lesson 1, view the PDF here.

To access other sections and lessons of the Aquatic and Marine Ecosystems: Leader's Activity Guide, view the EDIS topic page here.


1. This document is 4H347, one of a series of the 4-H Youth Development Department, UF/IFAS Extension. Original publication date May 1998. Revised November 2014. Reviewed October 2017. Visit the EDIS website at
2. Karen Blyer, state 4-H science coordinator; and Joy Jordan, 4-H curriculum specialist (retired); UF/IFAS Extension, Gainesville, FL 32611. Original version written by Jerry Cullen, Elise Cassie, Tammy Cushing, Wendy Flanagan, and Mike Harrington; UF/IFAS Extension, Gainesville, FL 32611.

Publication #4H347

Date: 1/25/2018

  • Critical Issue: Youth


  • Sarah Hensley