Mangrove forest island based communities?

In one of several threads here on proposals for floating cities

www.boatdesign.net/threads/floating-city.68272/

I said

The tropical predators that are a hazard to human habitation I was concerned with avoiding are large water snakes (like pythons), alligators and crocodiles, as well as malaria bearing mosquitoes.

One of the cool aspects of mangrove-forest created islands is that they might actually use up a bit of CO2 rather than increase the amount of climate changing atmospheric carbon. And properly managed, processed sewage could provide fertilizer to help feed island growth, and beach erosion from nearby land, as with other mangrove forest islands, provides the soil. Mangroves already contribute to slowing beach erosion in some locations. As sea levels rise, living roots to the sea bottom (shallow seas assumed) could grow.

So, fire away. What's wrong with the idea of creating floating communities on genetically re-engineered mangrove forests?

I'll start with the presumption that they would be genetically engineered resistant to insect plagues, like termites and locusts, and major plant diseases. (And obviously, the evolution of insects and plant diseases could eventually be an issue, as could unanticipated biological infestations.)

And I recognize that, as with almost anywhere, some engineering to support human habitation would be needed.

 

In general, people that would be attracted to that living environment would also be completely against GMOs.

 

A lot of boaters love the idea of living on an island. They aren't all hippies or the modern equivalent, nor do they all eat purely "organic" food, nor do they all worry about eating GMOs. Besides, I'm not necessarily talking about eating the island - though it might be possible to grow some foods on it. I would guess that a lot of people who worry about eating GMOs, live and travel in structures built partly out of artificial materials, and wouldn't mind GMOs being used to create the materials in them.

Very few domesticated plants and animals used as food stuff are in the original "natural" forms they had when people first encountered them - they have been purposefully bred (sometimes cross bred) and artificially selected through hundreds or thousands of generations. Somewhat before genetic engineering, people sometimes coated seeds with radioactive materials to create more mutations, as fodder for artificial selection. Perhaps other mutagens were used too. Even grape plants, such as many of those used to create wines, are often grafted because the roots of the original species have been killed off by plant diseases. GMOs are just the next obvious step, and for most of us, aren't that big a deal. And for some of those for whom it is, the main issue is that GMOs and the new materials in them, aren't normally tested for food safety in the same ways that artificial food additives are.

I once read an SF story in which grown genetically engineeredcoral houses in molds were proposed as a cheap way to build housing. I'm sure people have proposed the idea of other grown structures for human habitation. And of course, there have been tree houses for a very long time. This is somewhat along the same lines - not the home, but the land to put it on.

I spent a few weeks kayaking and camping around Florida, including around islands created by Mangrove trees. They really intrigued me. I hadn't even known that non-mythical living organisms could create an island. Very cool.

Floating communities are also sometimes proposed as an solution to rising sea levels in places where there isn't much higher altitude land available for human resettlement. One of the biggest problems with that is cost. I'm wondering whether grown islands could be a good economical starting point. Many people already live on barrier islands, which are at least as subject to erosion, and, because they don't float, are more subject to rising sea levels.

(Now, if perchance you don't believe rising sea levels are real, and are frankly almost inevitable, I don't know how to answer that, other than to say that I do. I worked with a lot of satellite data, and tend to believe that what they measure is fairly accurate, subject to appropriate limitations and ground truth calibration.)

 

In my observation, mangroves usually grow in the intertidal zone. A floating island will not be tidal, it will always float on top of the water. How will Mangroves do in those conditions?

Also, mangroves tend to be hot, muggy, muddy, slimy, smelly, buggy places. I'm not sure how many people would like to live among Mangroves.

 

There are mangroves, around the coast of much of Florida. Look at

Florida mangroves - Wikipedia https://en.wikipedia.org/wiki/Florida_mangroves

The island itself may not see tides on top of it, but it certainly can exist in a tidal zones. One of their characteristics is that they can extract fresh water for their own consumption from salt water, which more or less implies they are in areas affected by tides.

Some sources say they live in intertidal zones - which means the non-floating area around them is sometimes above and sometimes below water. It might also mean that at low tides they don't actually float, but rest on land. E.g., we camped and put our kayaks on the beach one night near the shore, and the shoreline had moved maybe 1/4 mile away by morning. You should be careful in such zones where and how you park your boats, to make sure high tides or storm surges don't carry your boats away. But that is true on many beaches.

They are warm climate species. But I was suggesting they be genetically re-engineered for colder climates. I honestly don't know whether that is theoretically possible.

One of the reasons I would like a cold water species is that I personally would be afraid to live in the vicinity of alligators or crocodiles. And I was told that Florida has poisonous snakes that sometimes drop out of trees into boats. Also, much of Florida has very hot weather in the summer, which I would want to avoid. If you hate swamps, maybe you don't want to explore such regions.

As best I understand it, not all types of mangroves can create islands, but I don't know the details. Apparently, during early stages, the islands can move around quite a bit, but eventually, the become rooted to the sea bottom, which limits their motion - though I think they sometimes uproot and move during major storms. Which means maps of such regions can go significantly out of date after a major storm. I had a GPS with several year old maps, which were quite inaccurate, presumably due to such motions.

But I'm not an expert.

Floating island - Wikipedia https://en.wikipedia.org/wiki/Floating_island says mangroves aren't the only plants that can create natural floating islands. Perhaps one of the others could do instead.

Based on the Internet, some people do live on mangrove islands. Some of the ones we saw and camped on had their own sand beaches, though maybe that is the land below the island - so you wouldn't have to live in the forest itself. We avoided the central forest, because it could have hid alligators, and (in around the Gulf of Mexico) crocodiles, though I was a bit concerned about camping on the sand too - doesn't seem like a nylon tent or bivi would provide much protection. (Some of the islands don't have sand beaches you can camp on - instead the park service has built platforms, which I'm not sure were high enough to discourage gators and crocs.)

 

Sorry, I didn't at first understand your question. I was specifically speaking about the types of Mangroves that form their own floating islands. I think in major storm surges, some Mangrove Forest Islands do get partly covered in water - maybe it depends on the length of the roots. So I admit they aren't a complete and perfect solution to rising sea levels. But I wonder if they could work for people who need or want to live next to the water.

Many of the places that could be adversely affected by rising sea levels, and that lack much same-country high ground to move to or the wealth and good governance to try to keep out storm waves and surges, have similar conditions.

Including some fairly popular places to live and play. Some people like hot. Except for a few locations with artificially maintained conditions, near shore locations in general, as well as many farm and wooded communities, tend to be muggy, muddy, slimy, smelly and buggy, but many people want or need to live there.

 

Well, it sounds like hell to me. The winds would be lower, humidity and heat high. I'd rather be on land, if not on a boat.

 

And of course, someone might chop down your trees, for firewood or charcoal:

Burning mangrove trees for a living: 'I'd quit tomorrow if I could' https://www.bbc.com/news/world-asia-66393515

 

If a floating island community in temperate zones were being contemplated, then I think there are other species of vegetation that would be more pleasant to live close to. Depending on the location, there are various rushes, grasses, sedges etc already adapted to the local conditions. Either way, I think some sort of built floating platform is required. Vegetation would be grown on or floating around that platform.

 

Here's some cool video of a couple of dozen small boats moving a floating bog island in the Chippewa flowage in Wisconsin: