Estuaries: Where the Tide Meets the Stream
2019, High School, Prose
Consider the oyster. A small, crusty, and drab creature, the lowly oyster is referenced in such literary works as The Iliad and featured in the Apicius, the oldest cookbook in history (metmuseum.org). The oyster is commonly found in estuaries like Mobile Bay. However, the abundance of oyster reefs globally has decreased by 85 percent over the past 100 years (Nature.com). Closer to home, it is a major staple of Gulf Coast cuisine. Eaten fried or raw with a large glass of sweet tea, oysters are consumed by the bucketloads, especially on the Causeway, a black ribbon of road that divides Spanish Fort, Alabama, from Mobile, Alabama. Framed on either side by the Mobile Bay, the Causeway is dotted with seafood restaurants like the Original Oyster House and Ed’s Seafood Shed. Mobile forms its own little world, with a bustling city, historic homes, and unique, family-run businesses—all centered around Mobile Bay, the perfect destination for fishing, boating, and swimming.
My childhood was filled with trips to my grandmother’s house in the backseat of my mom’s car, sandwiched between my siblings, eagerly awaiting the feel of the sun on my sunblock-slathered skin and the warm waters of Mobile Bay. Those days were filled with plastic shovels and buckets, picnics on the beach, pitchers of sweet tea, and endless hours of swimming, as well as water games like Marco Polo and Sharks and Minnows. The beach was where we built sandcastles and dug deep holes to reach the water. After the sky was streaked in oranges, reds, and pinks, my mother would load us, sunburned and drowsy, into her car, where we would fall asleep and dream of our next visit to our grandmother’s house.
Little did I know that Mobile Bay wasn’t just our little gem or an escape from the Alabama heat; rather, it provides far more than a fun summer outing. Mobile Bay is an estuary, or a place where the freshwater from streams and rivers mixes with the saltwater from oceans. Estuaries are critical for human development. It is no accident that the first civilizations were built around them and depended on the generous food and safety they provided. Estuaries are also critical for the ocean, as they filter sediments out of the water before it reaches the ocean. The height and salinity of the waters in estuaries is impacted by how the estuaries open into the ocean, thus enabling them to house a variety of species.
The Spanish moss-covered cypress trees make silent music in the wind. A faraway seagull screeches and pelicans dive into the water, rising with fish clutched in their beaks; water streams off their feathered backs. The Bay doesn’t look like much from the Jubilee Parkway Bridge, just a blur of brown water and grasses exposed during low tide, but up close, it is beautiful. Many take this visual bounty for granted, but on any fine-weather day, the Bay is spotted with boaters and kayakers, especially in the early morning, when fog curls around the bottom of the Jubilee Parkway Bridge. The Bay is home to a diversity of animals, as well, from the yellow-eyed osprey perching in the tops of the bald cypress trees to screeching seagulls, scuttling crabs, silvery-sided mullet, and red-bellied turtles. However, the yardstick of its health is not tied to the majestic blue heron or the scaly alligators sunning themselves on the riverbanks. No, none of these glamorous creatures are what scientists use to determine how healthy the Bay is. Rather, they rely on the fruit of the sea, also known as the oyster.
Oysters are commonly raised in estuaries like Mobile Bay. Estuaries are critical habitats for their occupants, and oysters are critical in maintaining that habitat; adult oysters can individually clean and filter 50 gallons of water each day (plough.com). As a result, they are crucial in maintaining the balance of freshwater and saltwater in estuaries such as Mobile Bay and in helping to maintain the ecosystems it contains.
Unfortunately, on the Gulf Coast, like elsewhere, the oyster population has been in serious decline due to overharvesting and dredging (noaa.gov). However, their disappearance is also caused by a larger, more insidious disaster: climate change. Climate change is largely due to human activity, particularly in the twentieth century, such as burning fossil fuels and clearcutting land for development; this has caused the Earth to become warmer and altered the natural greenhouse gas effect (climate.nasa.gov). As you can see, climate change is a worldwide crisis, threatening such diverse and precious resources as the Great Barrier Reef in Australia, but also places that are nearer and even more valuable to me: the shores of Mobile, Alabama.
Indeed, climate change is the most lethal threat to my summer home away from home. As Earth’s temperature continues to rise, the planet will undergo many destructive changes, such as more intense hurricanes and other weather events, like droughts and heat waves. Rising sea levels and the disappearance of ice in the Arctic Ocean are also predicted outcomes (climate.nasa.gov). But one of the most ignored effects of climate change is ocean acidification, which results from an increased level of carbon dioxide absorbed in water, causing its acidity to increase as well (climate.nasa.gov).
Approximately one-third of carbon dioxide emitted by humans is absorbed by the ocean, with over 400 billion metric tons of carbon emitted each year (eos.org). Together, the land and the oceans absorb about 212 billion tons of carbon and release about 206 billion tons (eos.org). Oceanic absorption of carbon dioxide results in the production of carbonic acid, which is detrimental to coral reefs, marine animals, and shellfish (eos.org). Although estuaries, wetlands, reservoirs, lakes, and rivers only cover four percent of the earth, they are critical for carrying carbon to the ocean; and Mobile Bay is not immune to the dangers of acidification (eos.org). The carbon that passes through the Bay ends up in the ocean, wreaking havoc along the way (eos.org).
Oysters are heavily affected by ocean acidification. The higher the acidity of the water, the lower the pH level, which means it contains less carbonate (newfoodeconomy.org). This, in turn, means the oysters’ shells grow thinner and weaker, causing them to die (newfoodeconomy.org). Younger oysters are more susceptible to the increasing acidity, meaning future generations of shellfish are at risk (newfoodeconomy.org). They, like other forms of sea life, depend on healthy estuaries. Estuaries are called the “nurseries of the sea” because of the vital role they play in nurturing the young of many species (noaa.gov). For example, the seagrass in Mobile Bay provides a safe space for young animals to feed and hide from predators. Detritus, or decomposing plant matter, provides nutrients for them, as well as for the plankton and bacteria found in the brackish waters. Estuaries like Mobile Bay have faced many challenges throughout the years, from the devastating effects of the pesticide DDT on the area’s pelican population to hurricanes that destroy fragile habitats. Yet the danger posed by ocean acidification far exceeds these threats.
The Bay waters splash on the cool, wet sand, wiping away footprints and dragging away bits of driftwood and leaves into the churning waves. The familiar smell of salt grows stronger after each wave that strikes the shore. Rising sea levels affect vegetation, animals, and businesses. Plants that should be above sea level end up drowning. It also affects dunes, eroding them and causing landslides and slumping. Climate change forces species to abandon their habitats in search of hospitable ones, becoming invasive species (www.iucn.org). Invasive species increase competition for survival and cause native species to die out. Saltwater intrusion, or saltwater stretching further inland, damages plants and animals that rely on the unique balance of freshwater and saltwater that estuaries produce. Higher sea levels mean that in the event of a hurricane, flooding would be catastrophic. Research shows that flooding caused by high sea levels and extreme weather will increase exponentially by 2050 (c2es.org).
For unlike litter on the beach or sewage runoff, climate change isn’t a campaign platform or a national problem; this issue can’t be voted away. This means that the small, yet significant Gulf Coast area will continue to be affected by climate change, from the murky depths of Mobile Bay to the tangled wetlands and the sandy beaches. In fact, climate change stretches from pole to pole, from the aquamarine Australian waters to the brown waves of Mobile Bay. Standing in the sand, my gloved hands lugging a trash bag with my Girl Scout troop, I soon realized how much damage a plastic straw or discarded wrapper could have on an ecosystem. However, it took me much longer to understand the threat of climate change and how this phenomenon, which seemed like a faraway crisis, would impact Mobile Bay and so many places like it. Not only the future of my summer getaway, but the future of all bays, lakes, rivers, and oceans is in jeopardy. Luckily, the key to saving our oceans isn’t an expensive piece of technology or even a miracle; rather, the way to halt climate change and save our homes is education, increased awareness of the vital role played by the estuary: the pearl in the oceanic oyster.
My happiest childhood memories involve swimming in Mobile Bay at my grandmother’s house. The crashing waves, salty air, and beautiful sunsets fostered my love for the water. I couldn’t get enough of the bobbing waves and the gentle noises they made when they broke against the shore. I was always protective of the Bay. As a child, I would attend the annual Coastal Cleanup with my Girl Scout Troop. I soon realized that garbage littering the shores was not the greatest threat Mobile Bay and oceans everywhere faced. The threat of climate change made me realize how important it is to get involved. Sure, many people say that climate change is an issue that makes them feel small. I think that such a crisis can only be solved by small people joining together to solve it. Climate change has the potential to be more disastrous, impactful, and life-changing than any world war or political outcome. Climate change isn’t just about us—it’s about our whole world, our oceans, and every animal that relies on them. Climate change can’t be dealt with by being thrown into a garbage can, like the trash left on the beach. Now, more than ever, we must act. We can’t wait until our world is irreversibly damaged. We cannot settle for any less than our beautiful oceans deserve. It must be with the mindset to be proactive, not reactive, that we solve the issue of climate change. We must put our oceans first.