As regular readers of this blog know, I’m setting up an 80-gallon planted tank. As I’ve slowly been working on my setup and layout, I’ve been thinking about what I want to raise in my tank.
I’m likely going to set up several smaller tanks around the 80-gallon to serve as breeding and grow-out tanks. I haven’t completely decided what I want to do with these smaller tanks yet, but I have some ideas and one of my priorities will be raising difficult freshwater fishes once everything is up and running.
Agriculture’s Wide Scope
While planning my various setups and thinking about breeding fish and propagating plants, I read a few articles that led me to think about the roles of aquaculture and agriculture in our world, and their affects on the aquarium hobby.
We hear a lot about aquaculture in the hobby these days. This is an important development, I think, both for our hobby and for larger commercial applications as well. Just as interest in aquarium aquaculture is growing, so is interest in commercial- and conservation-based aquaculture.
The first article that got me thinking about this topic discussed the National Oceanic and Atmospheric Administration’s recent forecast that the “dead zone” in the Gulf of Mexico may reach a record size this summer.
A dead zone is an area where increased nutrients have accumulated – a process called eutrophication – allowing algae to bloom in larger quantities than normal. The algae die, sink to the bottom and provide food for bacteria, which in turn use the decaying algae as a source of food and consume oxygen in the process.
The main cause of these dead zones is agricultural runoff from farms that feeds into waterways – including the Mississippi River – that are destined to dump into the Gulf of Mexico.
Terrestrial agriculture – the dry land cousin of aquaculture – affects the environment, conservation efforts and aquaculture, too, in addition to offering some biological and environmental parallels to what we can observe in our aquaria.
Any good aquarist is familiar with the nitrogen cycle in their aquaria. This dead zone phenomenon, which creates areas in the Gulf of Mexico that have a hard time supporting life due to the low oxygen levels, sounds a lot like a large-scale version of a poorly maintained aquarium.
This is somewhat similar to what can happen in an aquarium if excess nutrients are added to the system. We can look at an aquarium as a teaching tool to illustrate this kind of environmental science.
Though the size and makeup of the Gulf of Mexico creates an environmental system that is distinct from what we would find in aquaria, the same processes are occurring and similar outcomes may be observed.
Aquarists who add too much food or plant fertilizer, or who fail to adequately maintain their aquariums, are like farmers adding too much nitrogen (generally the principal nutrient in fertilizer and the main culprit in ammonia toxicity in aquaria) that end up fouling our waterways.
When nutrient buildup occurs in aquaria, generally plants can’t grow fast enough to lock up the excess nutrients before they become detrimental to fishes. This can lead to a toxic event where fishes die off in aquaria.
In a natural system as large as the Gulf of Mexico, fishes can generally escape areas of localized toxic nutrient buildup, and the system is so large that nutrient concentrations generally aren’t high enough to directly prove toxic to fishes.
As a result of this nutrient buildup, however, algae flourish (which can also happen in aquaria), die and serve as food for bacteria that consume oxygen.
But the creation of the dead zone and the low-oxygen levels in it are similar to problems aquarists are also familiar with. Aquarists often have to add aeration to their aquaria to prevent low oxygen levels from harming their fishes.
The low oxygen levels in aquaria may be caused by many things, but the end result can be very similar to what happens in the Gulf of Mexico every summer when warmer temperatures encourage algal and bacterial blooms.
Tying It Together
Though the size of the two systems we are comparing, the Gulf of Mexico and our home aquaria, are so different, we still realize that the same processes are occurring in both.
Thus, when we think about the problems of excessive nutrients in our aquaria, we have a special insight into what is occurring in nature. We know how we clean up the problem in our aquaria: We perform water changes and vacuum our substrate to remove excess nutrients.
Obviously, a water change isn’t going to work with the Gulf of Mexico, but we can guess what solutions might work by looking at how to deal with the problems in aquaria.
In general, scientists studying the problem in the Gulf of Mexico have recommended setting caps on nutrient runoff levels to stem these problematic algae blooms. Think of this like an aquarist limiting the amount of food given to fishes to prevent nutrient buildup in a tank.
Other solutions have been tried around the world, too. In Japan, for example, special nutrient-absorbing materials have been placed in waterways to prevent the nutrients from making it to the oceans in the first place. With the increasing popularity of nitrogen-absorbing filter media in aquaria, it’s easy to see the aquarium-hobby parallel.
In Australia, the government has committed money to help farmers reduce their nutrient runoff. Other potential solutions to this problem exist. Just think of what you might do in your aquaria, and you might see how these issues can be mitigated in natural environments.
Agriculture Affects Aquaculture
There are other side effects of dead zones like the one presently occurring in the Gulf of Mexico. First, traditional fisheries are negatively impacted as their potential catches either flee the area or die off when low oxygen levels hit.
Commercial aquaculture also suffers, because coastal areas become useless for raising commercially important species. Excessive agriculture runoff can end up hurting budding aquaculture efforts.
Just as hobbyists seek to limit their impact on wild fish populations by raising aquarium livestock in their tanks, aquaculture helps to take the pressure off of wild food fish populations by reducing our reliance on traditional fisheries as sources of food.
As aquarists, we are forced to be diligent or everything in our systems will die. However, the conditions created through our use of agriculture are harder to see and effective remedies are harder to implement.
This is another area where the aquarium hobby can bring conservation problems into focus. If more people kept aquaria, I bet they would better understand what happens when dead zones are created and what efforts are needed to reverse the trend.
By necessity aquarists are forced to learn to balance their aquarium systems if they want to have long-term success in the hobby. We’ll have to do the same thing in natural waterways if we want to prevent dead zones from harming the environment and our growing aquaculture industries.