Coral reefs are one of the ocean's most colorful and complex creations. I'm sure you have read about how they are in peril. Climate change, acidification, human development - all are having an impact, most often represented by coral bleaching which is the result of the loss of the symbiotic algae that lives within the coral.
I was reviewing several scientific papers and found that there are many studies going on to determine more specifically what is happening to the reefs. As it turns out, the external factors of temperature, pollutants, and others can trigger a variety of eco-systemic or internal components that adversely affect the coral. Oh, if it were only simple, then the solutions might be simpler too.
One study examined the impact on several species of reef fish and their aerobic scope, or ability to breath, in elevated temperatures. Ever felt your breathing was a bit more labored on a really hot day? Well, according to this study, reef fish can have a similar reaction when water temperatures rise. This causes a reduced capacity to absorb oxygen which weakens the health of the fish, its level of immunity, and overall lifespan.
Water quality was found, in another study, to impact the sensitivity of corals to coral bleaching. "Terrestrially-sourced dissolved inorganic nitrogen" or DIN was found to make coral more sensitive to the temperature threshold that triggers coral bleaching. Higher levels of DIN are often found in areas of human development in the form of runoff from urban development or construction.
The levels of nutrients within a coral reef system can also effect the balance between hard corals, anemones, and algae. All three live in relative harmony, with hard corals as the dominant species. But in the typically low-nutrient world of a healthy coral ecosystem, warmer temperatures can increase nutrient levels and, at various levels, the anemones become more aggressive towards the coral and at the highest levels, the algae becomes dominant.
Coral reef ecosystems are tremendously complicated and we are continually learning more about the inter-relationships of species and the environment. And not everything falls into perfect agreement. One study that reviewed the relationship between temperature and salinity at a mass bleaching in Thailand, found that salinity did not seem to play a critical role in triggering the event. Whereas, another study concluded that higher salinity levels can impact both the coral host and its symbiotic algae, effecting its long-term health.
We still have much to learn but the research must continue so that we have a clear understanding as to what is happening to the earth's coral reefs so that we can both potentially treat and prevent the abuses that are impacting these critical marine ecosystems.
A Sea Change is a very important film about ocean acidification and will be airing this Saturday, September 26th on Discovery's Planet Green channel at 8pm EST. The first feature-length film to cover this relatively new but critically important topic, A Sea Change documents the growing worldwide impact on our oceans from CO2 emissions which alters the ocean's delicate balance of acidity - its pH level.
When disrupted, these altered levels impact the growth of a myriad of ocean flora and fauna; in essence, disrupting the very foundation of the marine ecosystem.
"Imagine a world without fish. It’s a frightening possibility, and it could come true. A Sea Change follows the journey of retired history teacher Sven Huseby on his quest to discover what is happening to the world’s oceans. After reading Elizabeth Kolbert’s “The Darkening Sea,” Sven becomes obsessed with the rising acidity of the oceans and what this “sea change” bodes for mankind. His quest takes him to Alaska, California, Washington, and Norway as he uncovers a worldwide crisis that most people are unaware of. Speaking with oceanographers, marine biologists, climatologists, and artists, Sven discovers that global warming is only half the story of the environmental catastrophe that awaits us. Excess carbon dioxide is dissolving in our oceans, changing sea water chemistry. The more acidic water makes it difficult for tiny creatures at the bottom of the food web to form their shells. The effects could work their way up to the fish 1 billion people depend upon for their source of protein.
A Sea Change is also a touching portrait of Sven’s relationship with his grandson Elias. As Sven keeps a correspondence with the little boy, he mulls over the world that he is leaving for future generations. A disturbing and essential companion piece to An Inconvenient Truth, A Sea Change brings home the indisputable fact that our lifestyle is changing the earth, despite our rhetoric or wishful thinking.
A Sea Change is the first documentary about ocean acidification, directed by Barbara Ettinger of Niijii Films. Chock full of scientific information, the feature-length film is also a beautiful paen to the ocean world and an intimate story of a Norwegian-American family whose heritage is bound up with the sea."
What is of great importance in watching this excellent documentary, is that you don't watch it alone. If you're a regular reader of this blog then you are most likely a concerned conservationist who is knowledgeable about ocean acidification, but while seeing the film might provide you with further enlightenment, it is important that you get others who are not familiar with the issue to watch with you.
Invite your friends, heat up the popcorn, and make it a House Party! The more people who are made aware and informed of this very real threat to the health of our oceans, the better position we will be in to seriously address it.
The Abyss - no, not the movie; I'm referring to the deepest waters of the ocean in which the abyssal seafloor covers over 50% of the planet. This is an ecosystem that contains great biodiversity (scientists have barely scratched its surface and have come away with new and unusual species) and plays a key role in maintaining the ocean's proper balance of detritus management and nutrient, chemical, and mineral levels.
In the ocean, where do all the dead animals and plants go? Mostly into the abyss to be broken down, processed and, in essence, recycled. But a recent study shows that global warming and human activities are having an impact on this mysterious region. Temperature change and human activities such as ocean fertilization are impacting the level and quality of food or detritus that makes its way to the abyss. With this fundamental link in the chain being disrupted, there are many unforeseen but predicated consequences to the ecological structure and biodiversity of the ocean's deepest regions.
We think of global warming in terms of its impact on the sky, the land, and the ocean as far as the eye can see. But we need to remind ourselves it is a global issue - from the blackest edge of space to the blackest corner of the deep, deep sea.
Marine Protected Areas (MPAs) and No Take Reserves (NTRs) have been instituted worldwide, from the South China Sea to the North Atlantic to the Mediterranean, as a method to not only preserve marine environments but also provide a means to ensure a reasonable population outside of the zone for commercial fishing. While common sense might dictate that these zones would logically improve the health of a marine environment, there are many challenges in empirically proving it.
While an MPA or an NTR may have a defined boundary, those limits have not been, shall we say, "communicated" to the marine life below the surface and so spatial density, or spillover as it is sometimes called, becomes a critical component. A healthy zone that generates populations of species that extend beyond its borders and provides a reasonable commercial yield, does not do so in a vacuum. There must be a proper flow of incoming influences including plankton, coral, and fish larval stages and other biosystem factors - all of which pay no attention to a zone's arbitrary boundaries.
While preliminary results appear positive, there is a considerable amount of challenging research taking place:
Studying the impact of political/public use influences on the size (reduction) of a zone versus initial environmental recommendations (preliminary research indicates the negative effect is disproportionately larger than the amount of size reduction).
Researchers are often challenged by a lack of extensive baseline studies of ecosystems prior to the zone for use in evaluating against post-zone studies.
Much research needs to be done to document the relationship/effect of multiple MPAs or NTRs and how they interact with each other.
To date there have not been any major negative ecological effects attributed to MPAs and NTRs, but let's hope with more research over time, we will have the body of data to undeniably prove their effectiveness and how we can maximize or improve on that success for both environmental and commercial interests.
I was reading about two seemingly disparate animals: sharks and shellfish. And I came to realize there was a common thread to the life-threatening situations these animals are facing.
A recent report in the Norwegian scientific journal, Oikos, analyzed the impact on changes in seal predation behavior if the shark populations that preyed on the seals declined ("Do shark declines create fear-released systems?"). Pretty heady stuff, but through the researchers' computer models it was theorized that there could be major shifts in diets from shallower prey like herring to deeper water prey like pollock - where local sharks frequent, when the decline in shark populations has removed an element of fear that dictates a good measure of the seal's hunting behavior. Bottom line was that a decline in shark populations could produce a more significant change in the predator-prey hierarchy relationship than previously thought.
With shellfish, scientists are seeing an impact of warmer waters on various species that is producing population declines from deadly bacteria, among other factors. Oyster beds along the west coast of the U.S. are now seeing the effect (read recent article). The east coast has seen this effect, too. A platter full of shucked oysters may not be your cup of tea (it's not mine), but as filter feeders, shellfish play a critical role in maintaining water quality. When shellfish populations whither, bacteria and various types of algae explode and push out a wide range of sealife through water degradation and loss of habitat.
So, what's the connection? One is that both of these situations represent the domino effect that occurs within any complex marine eco-system. For every action, there is a reaction - sometimes a very severe or unexpected one. Another connection is that these are basically man-made problems - over-fishing and global warming - and will have an effect on commercial operations that involve these animals. So our actions come back to haunt us.
Certain marine issues can gain more traction and get more media attention or public sympathy and support. But in the end, we need to consider the overall complexity of this ecological jigsaw puzzle we call the oceans and give every issue its due.
Coral reefs are one of the ocean's most colorful and complex creations. I'm sure you have read about how they are in peril. Climate change, acidification, human development - all are having an impact, most often represented by coral bleaching which is the result of the loss of the symbiotic algae that lives within the coral.
Water quality was found, in another study, to impact the sensitivity of corals to coral bleaching. "Terrestrially-sourced dissolved inorganic nitrogen" or DIN was found to make coral more sensitive to the temperature threshold that triggers coral bleaching. Higher levels of DIN are often found in areas of human development in the form of runoff from urban development or construction.
Coral reef ecosystems are tremendously complicated and we are continually learning more about the inter-relationships of species and the environment. And not everything falls into perfect agreement. One study that reviewed the relationship between temperature and salinity at a mass bleaching in Thailand, found that salinity did not seem to play a critical role in triggering the event. Whereas, another study concluded that higher salinity levels can impact both the coral host and its symbiotic algae, effecting its long-term health.
