[ ˌbīōˈindiˌkātər ]NOUNnoun: bioindicator · plural noun: bioindicatorsan organism whose status in an ecosystem is analyzed as an indication of the ecosystem’s heath.Powered by OxfordDictionaries · © Oxford University Press
Amphibians are a common bioindicator. They absorb so much through their skin that they’re more quickly affected by pollution and contaminants than other organisms in an ecosystem. So, if the frogs start dying, it’s time to figure out what’s going on before the larger creatures start dropping off, too. But these typical bioindicators are generally used for an isolated ecosystem. What indicates the health of the planet as a whole? Well, I talked about this on Sunday to my students. To me, one of the most sensitive bioindicators for the planet is: The Ocean. Here’s what I told them…
In 2012, I traveled with SUNY Brockport to study San Salvador Island in the Bahamas. It was a Biology/Geology course with a focus on Global Warming. Now, some people hear “Global Warming” and they look outside at this harsh winter and scoff at the idea. Yeah…You’re taking the idea too literally and looking at it too locally – the same problem with most of humanity. We only care about the picture we live in and we fail to look at it as a whole. Or, we simply don’t get it. Like this guy:
It’s called a Greenhouse effect because of this: Picture a Greenhouse. It harbors life where it is warm, can get sunlight, and can breathe and grow. If you start a chainsaw in it, it will poison the air. Start a car, it will eventually choke you and everyone else out. Now, picture the Earth as a giant Greenhouse. Enough cars and we choke out. Also, trees make up the Earth’s “lungs” – so as we cut down trees, we cut down on the Earth’s lung capacity, and we accelerate us “choking out”. If we don’t die from the atmosphere, we’ll die from the side effects of the atmosphere becoming increasingly tainted.
(P.S. I stole these images from the Internet…they’re not mine…)
So global warming is our increased emissions of CO2 building up inside our Greenhouse. What does this mean for the planet? Well, did you know that a lot of theories believe life came from the Ocean? Whether you believe that or not, I think it’s hard to deny that the Ocean has some of the most ancient life forms on this planet. Even if you believe the Earth was subjected to some kind of flood, I think it’s arguable that a flooded planet would harbor ocean life before anything else. Furthermore, if you smooth out the planet so it’s completely flat, we would be living under 1.6 miles of water. So, before tectonic plates began changing the depths and creating land, life was in theory thriving in those watery depths.
Okay – so Ocean Life has been here for (relatively speaking) forever…but as my trip to the Bahamas proved, the Ocean is RAPIDLY DYING. We studied the coral reefs and parrotfish populations that live within those reefs. Coral reefs are incredibly sensitive – not just to human activity (jet skis, people breaking the reefs, ships, etc.), but to indirect human or atmospherical activity. In other words, the coral reefs to the Ocean are kind of like the amphibians to a small ecosystem. And, if the Ocean is the “origin of life” – or at least the oldest, longest-standing habitat for it – then its recent rapid depletion should make it the planet’s BIOINDICATOR that something is seriously wrong. So why is it so sensitive?
Coral reefs are the home to so many important organisms that keep incredibly biodiverse parts of the planet in motion. Some animals eat the organisms that live in the coral structures (the coral organisms that build the structures themselves). You can hear this if you hold your breath underwater and listen to the parrotfish. They scrape and crunch as they go along, so it’s kind of like an underwater static that gets really loud when you’ve found a whole colony of hungry fish. My favorite parrotfish is the Stoplight Parrotfish. Like most fish, Parrotfish have different phases. A Stoplight is an example of a fish with an Initial Phase:
Who then grows into my favorite, the Terminal Phase:
These Stoplight Parrotfish are also an example of an organism that can change its sex, theoretically allowing it to fill the community needs for reproduction. We kept journals of all the fish we saw, but we also took population counts on the different varieties of Parrotfish to add to our study of the reef’s health.
Of course, the easiest way to assess the health of the reef is to look at its literal backbone: the coral itself. In the Bahamas, besides actual reef damage, we’ve noted an alarming increase in what is called “bleaching”. This is when the coral blanches because the zooxanthellae – the coral organisms – die. It’s literally dead coral. To accelerate this loss, there are algae blooms moving in. These algae thrive on the various contaminants and pollutants that have been cropping up in our waters. This is also a problem in the Great Lakes, especially after a storm event that washes contaminants into the water. When algae thrives, it will block out light to organisms lower in the water. When it clings to the coral, it accelerates the death of the zooxanthellae, consumes light and resources, and spreads. It’s all a bad imbalance.
But the coral are also struggling to grow.
How do coral “grow”? Well, they build. They build onto their structure which is, essentially, made of limestone: Calcium Carbonate, or CaCO3. Coral organisms filter the water and get the minerals they need to build their homes. These homes house the organisms that feed and protect so much biodiversity in the water. The problem with Global Warming is… It’s destroying that basic chemical process.
Normally, the atmosphere has CO2. This CO2 precipitates in the ocean water, combining with H2O to create Carbonic Acid (like what’s in soda), hydrogen ions (H,+), bicarbonate (HCO,3-), and carbonate ions (CO3,2-). This balance is really important because it determines the amount of free protons in the seawater – and free protons determine pH. Life is very sensitive to changes in pH.
Well, CO2 dissolves very easily from its gaseous state into the water. The problem is, we’ve been increasing the amount of CO2 in the air so much that the oceans are acidifying. H,+ is the ion we look for to determine acid concentrations, and it’s exactly what’s being formed by all the excess CO2 in the air. As the ocean acidifies, the tendency is for bicarbonates to be produced over the carbonate ions. Meanwhile, there are calcium ions naturally in the water. These can only bond to the carbonate ions. When carbonate ions bond with calcium ions, they create calcium carbonate – or CaCO3. Yes, the exact thing coral uses to live and grow.
So, as we produce emissions, we create a more acidic ocean, we destroy the ability to make calcium carbonate, thereby choking out the coral, increasing the algae bloom problem which also chokes out the coral, and therefore destroying the habitat for incredibly diverse, ancient ecosystems.
Yes, I consider these habitats an enormous planet bioindicator, and it’s indicating that we’re destroying the Earth.
In just the 20 years our Professor had been taking students to a handful of reefs for data collection on the island, he has seen the coral cover and parrotfish populations diminish to, relatively speaking, next to nothing. These reefs used to look much more beautiful, but we had to swim far and wide to find coral that didn’t have colors being choked out by green and brown algae. We swam along “The Wall”, where the ocean literally drops from 60 feet deep to over a mile of water. Normally, one will spot a number of Hammerhead Sharks. The only shark we saw was a Nurse Shark who had come unusually far up the shoreline. You might think this is a relief, but we viewed it as a concern. This popular vacation destination – the Caribbean – is dying because of human habit, and tourists are definitely making that happen faster.
Since the 1900s, there has been a 30% increase of H,+ ions in the Ocean. Since the 1950s, the average temperature has increased by 0.31C in the top 300m of water. Coral requires 25-29C, so it’s pretty sensitive. Take a look at the changes in relation to the Industrial Revolution:
It’s predicted that 60% of the Earth’s coral reefs will be lost by the next 25 years. And what about the 25 after that?
The carbonate threshold is predicted to be reached by 2050. In other words, forget about retiring to snorkel in the reefs. They’re going to be gone in under 40 years – UNLESS these environments are able to adapt quickly enough. There have been prehistoric coral colony collapses that resulted in the corals we know today, but do we really want to be responsible for these threats to the planet?
To end on a less depressing note, check out how awesome the Triggerfish is when he swims: