Welcome Seasteading community! Seasteading isn’t just about floating homes, these floating communities are about evolving our relationship with each other and with the earth. It’s also about creating a more abundant and efficient world. To help bring Arktide’s vision to fruition, it is necessary to explore and integrate ecological systems to allow us to be resilient against the changing nature of our environment. Rather than fighting nature, we can develop a more harmonious relationship that allows nature to work in our favor. In this blog we will be looking into mangrove plants, what makes them so important, and how seasteading communities can benefit from this natural system.
Mangroves are unique shrubs and trees that grow in dense thickets or forests along tidal estuaries, in salt marshes, and on muddy coasts. Their characteristically exposed supporting roots project above the mud and have small openings (lenticels) through which air enters, passing through the soft spongy tissue to the roots beneath the mud. Mangroves are the only species of trees in the world that can tolerate saltwater. Some mangrove species live so close to the shoreline that they are flooded with salt water every day as the tide comes in and submerges their roots. All mangroves have evolved special adaptations that enable them to live in salty, oxygen-poor soil.
Mangrove forests can be found on the saltwater coasts of 118 tropical and subtropical countries, totaling more than 137,000 square kilometers (85,000 square miles). The largest amount of mangrove coverage can be found in Indonesia, where mangrove trees cover about 23,000 square kilometers (about 14,000 square miles). These forests serve as a buffer between marine and terrestrial communities and protect shorelines from damaging winds, waves, and floods– an increasing threat in a changing global climate with rising sea levels. With the ideal placement for seasteading communities also being in tropical and subtropical regions, mangroves provide a great source of natural protection for communities found in coastal areas.
With their roots submerged in water, mangrove trees thrive in hot, muddy, salty conditions that would quickly kill most plants. They have learned to survive through a series of adaptations, including a filtration system that keeps much of the salt out, and a complex root system that holds the mangrove upright in the shifting sediments where land and water meet. Some mangroves can grow in soils that reach salinities up to 75 parts per thousand (ppt), about two times the salinity of ocean water. However, most mangroves do better in ranges between 3 and 27 ppt. Scientists categorize mangroves as either secretors (those that actively rid their tissue of salt) and non-secretors (those that block the salt from entering their tissue), the two main adaptations developed to deal with water salt. Not only do mangroves manage to survive in challenging conditions, but the mangrove ecosystem also supports an incredible diversity of creatures, with some species being unique to mangrove forests. Promoting this kind of aquatic life in our various seasteading locations (which you can read about in our Deep Dive blogs) is a symbiotic relationship that is key to us at Arktide.
The underwater habitat that mangrove roots provide offers critical nursing environments for thousands of fish species, from 1-inch gobies to 10-foot sharks. The dense root systems restrict the flow of tidal water and encourage the deposition of nutrient-rich sediments. Some organisms will eat the leaves directly, especially crabs and insects, while other decomposers wait for the mangrove leaves to fall to the bottom and consume the decaying material. Microbes and fungi among the mangrove roots use the decaying material as fuel and in return, they recycle nutrients like nitrogen, phosphorus, sulfur, and iron for the mangroves. Other organisms rely on the structures created by the branching trees and their tangle of roots. Monkeys, birds, insects, and other plants all live in mangrove branches.
A major restriction for where mangroves can grow is temperature. The cooler temperatures of northern regions prove too much for the mangroves. A fluctuation of ten degrees in a short period of time is enough stress to damage the plant and freezing temperatures for even a few hours can kill some mangrove species. However, rising temperatures and sea level due to climate change are allowing mangroves to expand their ranges farther away from the equator and encroach on temperate wetlands, like salt marshes.
The soil where mangroves are rooted poses a second challenge for the plants as it severely lacks oxygen. Even though plants use photosynthesis to produce energy, they must then use that fuel through cellular respiration to power their cells and that process consumes oxygen. Most plants can easily take oxygen from gases trapped within the surrounding soil, but for mangrove roots this is not an option, and they need an access to air. Not only are mangrove roots underground, but they are also flooded with water up to two times a day. This unique environment allowed for the evolution of a variety of special structures that help the underground roots gain access to air, even when submerged by the tide.
Mangrove forests are excellent at absorbing and storing carbon from the atmosphere. As the trees grow, they take the carbon from carbon dioxide and use it as the building blocks for their leaves, roots and branches. Once the leaves and older trees die, they fall to the seafloor and take the stored carbon with them to be buried in the soil. Mangroves make up less than 2 percent of marine environments but account for 10 to 15 percent of carbon burial. One acre of mangrove forest can store about 1,450 pounds of carbon per year. Blue carbon ecosystems like this can be up to 10 times more efficient than terrestrial ecosystems at absorbing and storing carbon long term, making them a critical solution in the fight against climate change.
Despite their critical importance, mangroves are disappearing at an alarming rate around the world. The biggest threat to mangroves is the emergence of shrimp farms, which have caused at least 35 percent of the overall loss of mangrove forests. Once the shrimp reach maturity, between three to six months, the ponds are drained so the shrimp can be harvested, and toxic water that contains the shrimp’s waste, uneaten shrimp feed, pesticides, chemicals, and antibiotics is released into the surrounding environment where it harms local ecosystems. As global temperatures rise so will sea level. It’s a phenomenon that is expected to cause trouble for mangroves across the globe. During past changes in sea level, mangroves were able to move further inland, but in many places human development is now a barrier that limits how far a mangrove forest can migrate.
The value of mangroves comes from its ability to modify and support the surrounding environment. The complicated root systems absorb the impact of waves which allows for the buildup of sand, dirt, and silt particles. The roots even hold onto those sediments which leads to better water quality and a reduction in erosion. Mangroves further improve water quality by absorbing nutrients from runoff that might otherwise cause harmful algal blooms offshore. Both coral reefs and seagrass beds rely on the water purifying ability of nearby mangrove forests to keep the water clear and healthy. It is important that we acknowledge this and help this species thrive to help us thrive.
Mangrove trees are a plant that can help us at Arktide achieve many of our goals when it comes to creating these seasteading communities. Purifying the water, attracting marine life, revitalizing coral reefs, and even protecting against changing climate conditions are all goals of ours, and mangroves can help us do that. Not only can mangroves help us, but we can also help mangroves by keeping the species alive, thriving and reproducing.