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Introduction to the Barnegat Bay Estuary

Level: 4-6

Subject: Science

Time Frame: One, 45 minute class period


Using a PowerPoint presentation and revisiting the model that was created in the ground water / aquifer lesson plan, students will learn about estuaries. They will then apply what they’ve learned about the processes of mixing between fresh and salt water to discuss the implications of water withdrawal for human use will have on the Barnegat Bay.  Students will assess factors that influence the amount and location of brackish water in the estuary, as well as think about how this mix of fresh and salt water forms a unique estuarine ecosystem that sustains a large number of organisms that live in the estuary and nowhere else.

Image source:  

NJ Core Content Standards

STANDARD 5.1 (Scientific Processes) All students will develop problem-solving, decision-making and inquiry skills, reflected by formulating usable questions and hypotheses, planning experiments, conducting systematic observations, interpreting and analyzing data, drawing conclusions, and communicating results.

A. Habits of Mind

·          Evaluate the strengths and weaknesses of data, claims, and arguments.

·          Communicate experimental findings to others.

·          Recognize that curiosity, skepticism, open-mindedness, and honesty are attributes of scientists.

B. Inquiry and Problem Solving

·          Identify questions and make predictions that can be addressed by conducting investigations.

·          Collect, organize, and interpret the data that result from experiments.

STANDARD 5.8 (Earth Science) All students will gain an understanding of the structure, dynamics, and geophysical systems of the earth

B. Atmosphere and Weather

·          Describe the composition, circulation, and distribution of the world's oceans, estuaries, and marine environments.

·          Describe and illustrate the water cycle.

D. How We Study the Earth

1.        Utilize various tools such as map projections and topographical maps to interpret features of Earth's surface.

STANDARD 6.6 (Geography) All students will apply knowledge of spatial relationships and other geographic skills to understand human behavior in relation to the physical and cultural environment.

A. The World in Spatial Terms

·          Translate maps into appropriate spatial graphics to display geographical information.

·          Use geographic tools and technologies to pose and answer questions about spatial distributions and patterns on Earth.

B. Places and Regions

·          Explain how regional systems are interconnected (e.g., watersheds, trade, transportation systems



·        PowerPoint (provided in estuary lesson plan.ppt and pdf format)


·        Student worksheet (provided in editable word format and in pdf format


       Graphic organizer (provided in editable powerpoint format and in pdf format)


·        Maps of the Barnegat Bay and surrounding watershed (if available)


       Globe   / world map (if desired to extend lesson to discussion of world oceans / famous  estuaries etc).


·        Aquifer model (from previous class)


·        Food coloring (blue and yellow)


       Water and squirt bottles


·        White paper


·        Blue water soluble marker








Describe what an estuary is and where it would be found


Explain some of the reasons why estuaries are important


Describe the pattern of salinity along the axis of the estuary


Explain how changes in freshwater input to an estuary change the distribution of salinities within it


Describe some of the main features of the Barnegat Bay Estuary


Name some of the unique species found within this estuary


Evaluate the effects of the changes in salinity within the estuary upon the communities of organisms living within it

Anticipatory Set


Teacher will initiate a classroom discussion asking students what type of activities they like to do in the summer (particularly using the water).

Answers will probably include: swimming, crabbing, fishing, clamming, boating, and possibly they or someone they know has gone boating, sailing, canoeing or kayaking.


Teacher will point out that although there have been times they may have swum, fished, or boated in the ocean, chances are they have also done all the activities (mentioned above) in the Barnegat Bay. 


Teacher should continue a conversation asking students if they ever noticed differences between the bay and ocean.

Teacher can guide the conversation by asking about the waves (or the lack of), the look, feel, and size of the sandy / muddy beach, the color, and taste (if accidentally swallowed or licking lips after a swim) of the water, and the animals (seagulls and sand crabs versus ducks and blue clawed crabs) and refer to the previous lessons about groundwater and the Barnegat Bay watershed for a better understanding of the upcoming information. 

Sequence Instruction

1)      Teacher will ask students why there is a difference in the taste of water between the bay and the ocean. (Students should be encouraged to use their newly acquired knowledge of surface and ground water movement and the watershed.) 

2)      Using the PowerPoint provided, (in ppt and pdf format) if desired, as well as models and other manipulatives, or simply using maps and reviewing the materials provided in the resource section of the lesson, teachers should review the basic properties of Estuaries and the Geography of the Barnegat Bay following approximately the order below.  A worksheet (provided in editable word format and in pdf format and graphic organizer (provided in editable powerpoint format and in pdf format) are provided.  Teachers can choose to have students complete one or other or both of these as the lesson unfolds.  Alternately either one can be used as an assessment tool at the completion of the learning unit.

3)      Using the PowerPoint (slides 1 – 5), the teacher will introduce the idea of an ESTUARY as a place where fresh water and salt water meet and mix together.  As each slide progresses students should complete the worksheet provided.

4)      Using the model previously made in the groundwater / aquifer lesson, students should review the pathways traveled by fresh water through a watershed and into the Bay using water dyed blue with food coloring (surface, and groundwater flow). 

5)      Using the model, teacher will present the class with a bottle of water that has been dyed bright yellow using food dye and explain to them that this represents salty ocean water.

6)      Teacher will add the yellow water until an appropriate mixing of the blue and yellow colored waters in the “Bay” at the downslope end of the model creates a nice teal. 

7)      Teacher can ask students to recall what kind of water is represented by this “teal” mix of  fresh and salt water.  (Answer:  brackish)

8)      Returning to the PowerPoint the teacher should emphasize that, as in the model they’ve just worked with, BOTH surface AND ground water are important sources of fresh water into the Barnegat Bay.  This  freshwater mixes with the salty ocean water that enters the bay through the inlets between the islands which creates water that’s saltier than fresh water and fresher than ocean water.  Again, students should be reminded that water of such intermediate salinities is called brackish.  

9)      Students will be asked if they think that the levels of salinity in this brackish water is going to be uniform across the entire bay. After discussion, teacher will emphasize with the map and PowerPoint images, that salinity tends to change gradually along the entire estuary with fresh water nearest the river, and saltier water nearer the ocean.

10)  Students will then review the rivers and watersheds of the Barnegat Bay, along with other landmarks that might help orient the students to the locations being discussed.   These are the SURFACE water inputs to the Bay:


     Information teacher should know and teach: The most easterly portion of the bay is enclosed by two barrier islands, as Long Beach Island and Island Beach. On the eastern side of these islands is the Atlantic Ocean. The different exposure each side (West and East) of the islands to fresh versus salt water as well as to ocean waves offer a better explanation of the differences the students may experience when they are enjoying the beaches or water sports on one side of the islands versus the other


    Students will be prompted to recall / or shown if they are not familiar with this idea, that salty, ocean water enters the Barnegat Bay at the inlets or gaps between the barrier islands.  Again a map should be used to review the locations of the Barnegat Inlet, Bayhead-Manasquan Canal, Manasquan Inlet, Little Egg Harbor Inlet, as well as Island Beach and Long Beach Barrier Islands


    Teacher should review the fact that the ocean that is off the New Jersey coast is the ATLANTIC ocean.

                                                 i.      If desired, teachers may use this opportunity to review the fact that the world has FIVE major oceans, The Atlantic, The Pacific, Arctic, Southern (Antarctic) and the Indian Oceans. A map of the world or a globe should be used to demonstrate the locations of these oceans.

11)  Students will be asked where they think the salinity would be highest within the Barnegat Bay. (Answer:  closer to the bay’s inlets) 

12)  Teacher will explain how the special environment of the estuary (shallow, brackish water) forms a home for a specialized group of animals. These include underwater grasses called seagrasses, as well as lots of fish and crabs under the water and birds above.

13)  Share with the student the fact that much of the seafood that we eat is made up of species that live part or all of their lives in estuaries, so healthy estuaries are important not just to the animals and plants living there, but to us in terms of food supply, as well as the economic benefits that they provide (some students may even have a family member or friend who is a commercial fisherman/woman, or work to support the recreational fishing industry in bait and fishing specialty stores) and others may have fished or gone crabbing in the Bay and eaten the animals they caught.

14)  A couple of slides are provided to give the students a sense of the animals living in the Bay


    Jellyfish in seagrass


    Mud turtle


    Stickleback (small fish) in seagrass


    Blue Crab


    Great Blue Heron





15)  Teacher will explain to students that the position of the boundaries between fresh, brackish and salt within the estuary depend on two main things….

a.       How much fresh water comes in

b.       How much ocean water comes in

    How much freshwater comes in depends on     


The amount of rainfall in the watershed


The amount of water used by humans in the watershed that is removed from the system

The less fresh water there is the more the ocean can push into the estuary so the 0 salt line (where you can’t measure any salt) will tend to move a long way up the river.   The more fresh water there is, the more the 0 salt line will push down the estuary toward the ocean

How much saltwater comes in depends on


Tides (more salt water comes in on big tides than small ones). In the area of the Barnegat Bay tides are very small, so this isn't a big factor


Wind  A strong wind off the ocean can push more salt water into the Bay than is usually there

Of these two, the impact of changes in freshwater inputs tend to be stronger than that of differences in ocean inputs.

16)  Teacher will ask students what they think the varying salinities in the water would mean for the kinds of animals and plants that live. If the students have difficulty with this question, teacher can relate to the climates in Alaska, NJ, Florida, etc. Just how people like different climates to live in, or truly can’t survive in extreme environments, such as Antarctica, all types of organisms need different types of water or can’t live in extreme salinities or fresh water.

17)  This idea can perhaps be more easily seen in the simple schematic (slide 17), in which the boundaries between different levels of salinity change depending on whether there is high or low freshwater input.

18)   If humans pump water out of rivers or aquifers, then there will be less fresh water entering the estuary.  Teacher should ask the students what they predict the effects of this will be for the location of waters of different salinities in the bay (will be like a “low flow” or drought year).

19)  Teacher can discuss how this might be stressful for the organisms that live in the estuary especially when water withdrawals by humans are added on top of the effects of a drought year.

20)  This will result in unhappy animals in the estuary (final powerpoint slide)

21)  Teacher can choose to enhance this lesson plan with additional materials (a collection of which is presented below) that they feel would enhance students understanding of the materials or meet specific learning objectives within their curriculum.

22)  One example of a potential extension activity would be to Students can discuss the physical makeup of the Barnegat Bay Estuary, in addition to the varying salinities, that can offer a habitat for a diverse population of organisms.


    Students can discuss other features of the bay such as where they believe the: fresher water would be found (along the western coast where the rivers meet the bay), where the bay would be shallower (around the edges near the lands), or deeper (in the middle of the bay).


    Students could also contemplate what the benefits would be for organisms to live in shallow versus deeper levels in the bay. (Living on or near land versus in the water, hiding from predators in the seagrasses or mud, or the darkness of deeper areas,


    They might also discuss how shallow waters would be warm in summer and cold in winter whereas the deeper water will tend to stay more or less the same temperature year round, so deep water would be colder than shallow water in the summer, but would be warmer than the shallows in winter)  




If resources permit, have students watch one or two short videos about estuaries for a better understanding and appreciation for the Barnegat Bay. These can be enjoyed as a class or students may be given the website to explore during their computer time.




Teachers can use the accuracy of answers on students' worksheets to assess their learning in this unit.

If additional assessment is desired, students could be provided with a photocopied image of an Ocean County map with the Barnegat Bay and asked to label areas with terms such as:  Atlantic Ocean, Barnegat Bay, salt water, freshwater, brackish water, barrier islands, and inlet(s).

Students could also be asked to write a brief paragraph summarizing what effects removing surface and or ground water from the watershed  will have on the organisms of Barnegat Bay.


Exit Activity


Have students write / discuss / share one fact they learned about estuaries today.


If there is no PowerPoint/computer projector, teacher can print out the pictures that are supplied and have them converted to transparencies to present on an overhead, or simply printed to be passed out to groups of students. 

Barnegat Bay: An overview 

EPA's Exploring Estuaries Site:

What is Barnegat Bay?

Wikipedia's Barnegat Bay Page:

Rutgers University Barnegat Bay Resource Page:

Barnegat Bay watershed map


Background Information

What is an Estuary?

An estuary is a partially enclosed body of water, and its surrounding coastal habitats, where saltwater from the ocean mixes with fresh water from rivers or streams.


In fresh water the concentration of salts, or salinity, is nearly zero.

The salinity of water in the ocean averages about 35 parts per thousand (ppt).

The mixture of seawater and fresh water in estuaries is called brackish water and its salinity can range from 0.5 to 35 ppt.

The salinity of estuarine water varies from estuary to estuary, and can change from one day to the next depending on the tides, weather, or other factors


Salinity also affects chemical conditions within the estuary, particularly levels of dissolved oxygen in the water.


The amount of oxygen that can dissolve in water, or solubility, decreases as salinity increases.


The solubility of oxygen in seawater is about 20 percent less than it is in fresh water at the same temperature.


Estuaries are unique

Estuaries are strongly affected by tides and tidal cycles

Yet, they are protected from the full force of ocean waves, winds, and storms by reefs, barrier islands, or fingers of land, mud, or sand that surround them.

The characteristics of each estuary depend upon the local climate, freshwater input, tidal patterns, and currents.

Truly, no two estuaries are the same.

They provide goods and services that are economically and ecologically indispensable.

Estuaries also help to maintain healthy ocean environments.

Filter out sediments and pollutants from rivers and streams before they flow into the Oceans, providing cleaner waters for marine life.


Estuaries provide critical habitat for species that are valued commercially, recreationally, and culturally.

Often called nurseries of the sea

Provide vital nesting and feeding habitats for many aquatic plants and animals.

Most fish and shellfish eaten in the United States complete at least part of their life cycles in estuaries.


Eg: salmon, herring, and oysters,

Birds, fish, amphibians, insects, and other wildlife depend on estuaries to live, feed, nest, and reproduce

Important: seagrasses and mangroves need estuaries to live.

Estuaries provide habitat for more than 75 percent of the U.S. commercial fish catch and a large percentage of the recreational fish catch

The total fish catch in estuaries contributes $4.3 billion a year to the U.S. economy


Water flowing through the watershed drainage

Water flowing into the estuary, and from the land, the water brings in nutrients. This is one of the reasons estuaries are such productive ecosystems.

Can often bring all of the pollutants that were applied to the lands in the watershed.

For this reason, estuaries are some of the most fertile ecosystems on Earth, yet they may also be some of the most polluted.


Estuaries protect

Coastal areas, inland habitats and human communities from floods and storm surges from hurricanes.

When flooding does occur, estuaries often act like huge sponges, soaking up the excess water.

Estuarine habitats also protect streams, river channels and coastal shores from excessive erosion caused by wind, water and ice.

Water quality by filtering out dirt and pollution.

To learn more about how estuarine habitats filter the water from rivers and land before it enters the ocean:


Estuaries are fragile ecosystems that are very susceptible to disturbances.

Natural disturbances caused by the forces of nature.

o       winds, tidal currents, waves, and ice

Anthropogenic disturbances are caused by people.

o       pollution, coastal development, and the introduction of non-native species to an area.

(Estuary factoids copied from and


TEACHER FEEDBACK REQUEST:  We are always to working to improve these lesson plans. If you use this lesson plan, we'd love to hear from you with your thoughts, comments and suggestions for future improvements.  Please take the time to fill in our survey at  Thanks!


 © 2009.  Amanda Traina (Author), Louise Wootton (Editor)



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