1/14 & 1/16:  Agua Hedionda Discovery Center

Agua Hedionda Discovery Center                                                                              Cost:   $2 

Time:  9:30 - 12:00

Location:  1580 Cannon Rd., Carlsbad, CA 92008  (760) 804-1969                       

Accessible: Yes.  However, outdoors along the trails, the  terrain can be a little rough. 

Description: Come visit the Agua Hedionda Discovery Center, an inspiring venue sponsored by the Agua Hedionda Lagoon Foundation, a 501 (c)(3) organization that is dedicated to public education and outreach.  The Foundation’s work is to preserve this 400-acre watershed and make it available to the public to learn about and enjoy its wide array of flora and fauna.  

Directions: From I-5 North, take exit 48 for Cannon Road, and turn right onto Cannon Road.  Turn left onto Faraday Avenue.  The destination will be on your left.  

Parking: Free parking is available at the facility.

Website(s): https://www.aguahedionda.org/discovery-center

This week, we travel to the Agua Hedionda Discovery Center, a 400-acre lagoon.  The unique thing about this venue is that it is more than a lagoon, but is actually an ecosystem.  It is one of the threatened coastal wetlands on the Southern California coastline.  In our lesson, we will learn about the Agua Hedionda Lagoon, and the features of the various ecosystems represented in this unique natural resource.  We will also look at some challenges faced by similar types of ecosystems.  

A unique feature of Aqua Hedionda is that the freshwater creeks drain into a low-lying area meeting the sea.  The ocean pushes tides and sands against the land as the creek drains its fresh water and sediment into the sea.  This fixture of fresh and salt water forms a brackish environment.  

Brackish water is water having more salinity than freshwater but not as much as seawater.  It is the type of water that is seen at the Lagoon.  The most extensive brackish water habitats are estuaries where a river meets the sea. (contributors, 2019)  The salinity of the water varies with the seasonal influence of rain and storms.  

Tides in the Lagoon ebb and flow twice a day.  The rates of flow vary due to gravitational forces of the Sun and Moon on the Earth.  When the Earth, Sun and Moon are aligned, the Moon is in its full and new phases.  At this time, strong gravitational forces cause very high and very slow tides.  These are called spring tides (the action of the seas springing out and then back)

When the sun and moon are perpendicular to the earth, the moon is in its quarter phases.  The weaker gravitational force results in a much lesser difference between high and low tides.  These are called neap tides.  

Twice a day, the tide rises to flood the Lagoon.  It then ebbs, leaving much of the mudflats exposed.  This tidal action creates a nutrient-rich environment which supports a variety of organisms such as clams, crabs and worms.  70 species of fish live in the Lagoon.  Look for flounder, white seabass and stingrays.

Birds are well represented at the Lagoon.  There are 192 species of birds.  The surrounding habitats support not only healthy and migrating birds, but also birds which are endangered or threatened with extinction.  Look for California Brown Pelicans, California towhees, red-tailed hawks and Anna’s hummingbirds.  

Caulerpa taxifolia is a type of algae which has been nicknamed “killer algae” because of the effect on marine ecology.  It is extremely fast growing and can destroy and replace coastal marine life such as kelp forests. Large areas of the Mediterranean Sea and sites along the Australian coastline have been irreversible affected by these algae.

In response, the Southern California Caulerpa Action Team (SCCAT) was formed by the Agua Hedionda Lagoon Foundation to respond to the invasion.  Funds were generated by grants from the government and many private organizations.  Diving teams spread heavy tarps over the algae.  These tarps were weighted at the edges and chlorine gas was injected to kill the seaweed.  This activity continued for months.  Ultimately, on July 12, 2006, Caulerpa taxifolia was eradicated.   

It is now illegal to possess, sale or transport Caulerpa taxifolia throughout California.  

You will spend time at the Discovery Center.  There, you will find some exhibits, hands on activities and a native plant garden.

Some of the exhibits include:

·         History hall:  The history hall features information on the different birds of the lagoon, and a history of the area dating back 5000 years. 

·         Reptile room (both native and non-native species)

·         Aquariums: There are three salt-water aquariums and a touch tank

·         California native garden to provide you with some ideas for your garden

·         An exhibit to introduce you to Robert Kelly, an émigré who travelled across the US and ended in San Diego

·         The column of life exhibit which offers some visualization of how the lagoon functions within each layer

·         An aquaponics exhibit which combines breeding fish with gardening in a no soil environment

·         A live bee exhibit courtesy of the Encinitas Bee Company

·         Living walls (vegetation built into the wall of the center)

·         Pollinator path: Installed in Spring of 2019, it features mosaic stepping stones which encompass the area to the south of the Discovery Center. 

·         Luiseno History and cultural exhibit:  This was the first major exhibit opened to the public on Earth day of 2006.  This exhibit includes photographs and displays featuring Luiseno culture, with an emphasis on the role that native plants played in the Native American lifestyle.

·         And some really cute animals, such as Piper the Pig, Hank the Guinea pig and Marshmallow the fluffy rabbit.

The Luiseno Indians were original inhabitants of this area.  They found many uses for the native plants of the area.  Some of these plants and their uses include:

Lagoons are an important coastal feature which provides ecosystems for a variety of species.  A review of literature on lagoons (Anthony, 2009) outlines some of the challenges facing lagoons.

As we have learned in this lesson, and will hear in our visit to the Lagoon, coastal lagoons are highly productive ecosystems.  They support a variety of habitats such as salt marshes, seagrasses and mangroves, which supply food and nutrients to fish, birds and more.

Because they have relatively low flushing rates, they are favored by primary producers like aquatic plants and phytoplankton.  Nutrients transported to the lagoons flow and exchange with the ocean.  Because nutrient availability can limit primary productivity, coastal lagoons have higher rates of primary production and can then support secondary production.  

Socially, lagoons can be highly valued.  The value can be organized into four categories:

·         Pragmatic (“use” values, such as commercial, recreational and tourism)

·         Scholarly (activities that expand our knowledge about lagoon systems)

·         Inspirational (creativity projects such as photography and landscape painting, and settings for films, literature, songs and other artistic expressions)

·         Tacit (unspoken values which include the enjoyment of scenery, sounds of waves and birds, and other sensory landscape features.  

Climate change is expected to impact lagoons directly, in terms of sea level, temperature, precipitation and storminess.  

Accelerated sea level increase is a threat to low-lying, shallow-gradient coastal ecosystems.  Although lagoons are equipped for changing sea levels, accelerated sea level may lead to hardened shorelines on developed coastlines which can impede migration and increase vulnerability to storm damage and structures.  

Accelerated sea levels can lead to steeper and more narrow barriers, shortening the length of inlets and increasing the rate of exchange with the ocean.  Light penetration may occur with submerged aquatic plants, which can then reduce the photosynthetic potential and change the nutrient composition.

Changes in air temperature influence the water temperature of slow-moving and shallow water such as coastal lagoons.  The rate of temperature increase in lagoons is approximately four times greater than that of the ocean.  Water temperature influences dissolved oxygen concentrations, as well as the physiology of lagoon organisms, range of various species and the patterns of migration.  

Changes in precipitation patterns are variable, and disagreement persists on how this will affect components of the water cycle, such as stream flow, soil moisture and groundwater storage.  Precipitation patterns can also affect the physical and ecological characteristics of lagoons through changes in salinity and dissolved oxygen.  Increased freshwater can contribute to the stratification of deeper lagoons which can create hypoxia in the bottom of the water.

Storms can also affect lagoons through over wash and erosion. (Over wash occurs when sediment from the front of the barrier is eroded onto the back barrier and into the lagoon).  Storms can cause an increase in sea levels and erosion of natural barriers.  Storms may also cause more breaching of barrier islands which can increase the rate of exchange with the ocean and affect flushing rate and salinity of lagoons. 

Ultimately, time will tell what effect climate change has on our lagoon system.  Unlike eradication of non-native algae, climate change is global and cannot be controlled within a particular setting.  

The Agua Hedionda Discovery Center will offer a glimpse into evolving ecosystems.  You will see how the combination of fresh and salt water create a variety of ecosystems which are important for preserving species of plant and marine life.  It will also help educate on the importance of a global approach to maintaining our natural resources, and continuing to create havens for endangered species and habitats.  

Anthony, A. e. (2009, August). Coastal Lagoons and Climate Change: Ecological and Social Ramifications in U.S. Atlantic and Gulf Coast Ecosystems. Retrieved from Ecology and Society: https://www.ecologyandsociety.org/vol14/iss1/art8/

contributors, W. (2019, December 10). Brackish water. Retrieved from Wikipedia, The Free Encyclopedia: https://en.wikipedia.org/w/index.php?title=Brackish_water&oldid=930130157

discovery center. (2018, January). Retrieved from aguahedionda.org: https://www.aguahedionda.org/discovery-center

lagoon. (2015, January). Retrieved from aguahedionda.org: https://www.aguahedionda.org/lagoon