May 20, 2018

Lasting leaf impact...The potential of mangrove leaf litter in aquariums.

I was thinking about our world of brown water, biofilms, and algae the other day, and it hit me that, as a community, we've actually made it easier on ourselves.

In my brackish water system, as in my blackwater system, I regularly find myself topping off with new leaves. In this case, it's exclusively mangrove leaves.

The interesting thing I'm finding out about mangrove leaves is that they seem to last a very long time before completely breaking down; often two months or more in my experience.

Mangrove leaves possess specialized cell structures, including tannin cells (hello!), and sclerieds, structures within the leaf tissue which are thought to provide mechanical "support" to the leaves and discourage herbivorous predation.

Perhaps this accounts for their durability and it certainly accounts for their ability to impart color to the water via tannins over extended periods of time? Possibly. I have noticed a nice tint to my brackish water aquarium, and it's consistent with the quantity of the mangrove leaves.

I also think that mangrove leaves are a more than suitable for use in a freshwater (blackwater) systems. I use them in my home aquarium, and the tank is doing great!

Mangroves also provide a unique ecological environment for diverse bacterial/mocrobial communities. I think the "productivity" of mangrove leaf litter beds in brackish water systems is every bit as great and important as it is in freshwater ecosystems.

In addition to bacteria, mangrove ecosystems are home to a group of fungi called “manglicolous fungi.” These organisms are vitally important to nutrient cycling in these habitats...The benefits for our closed aquatic ecosystems from these organisms are obvious!

There is also evidence, in both brackish and marine habitats, of higher fish population densities in areas which have accumulations of decomposing leaves and mangrove materials. In several geographic locales worldwide, researchers have found a highly significant relationship between amounts of mangrove detritus and fish densities or biomass in mangrove estuaries and creeks.

Such productive habitats are naturally of interest to us as fish people. And with the ability to at least simulate some aspects of them, the time has never been better to research mangrove habitats and the functions of the leaf litter they contain, from the comfort of our own aquariums!

So much to explore. SO much to figure out here! With all of the potential of brackish water aquariums and the use of mangrove leaves in particular, the possibilities are truly unlimited!

As we gain more an more experience in utilizing mangrove leaves in our aquariums, I believe that we may see more success with brackish water AND freshwater life forms. The unique biology which these leaves support, and the compounds they release as they break down form a basis for one of Nature's most fascinating ecological habitats.