What am I reading today? Well its been busy, but that kind of slow busy that drives you nuts. So I haven’t been updating as often as I’d like to. But I came across this article today, and wanted to share it with you. Mostly because of the cool picture listed above. But also because it touches on a rather “hot” current science topic, and one that is vitally important for us all to understand. Humans are constantly pumping more and more carbon dioxide into the atmosphere. This is not up for debate. One consequence of this is global climate change. In the scientific community, this is not up for debate either (although the mainstream media makes it seem much more debatable). But another unintended and, until recently, unrecognized consequence of carbon emissions is ocean acidification. I won’t bore you with the chemistry details, but the main idea is that CO2 is admitted into the atmosphere, and from the atmosphere it is diffused into the oceans. Once absorbed into the oceans, it alters ocean chemistry (see cartoon above from Oceana). This altered ocean chemistry can affect a multitude of organisms, but it particularly harmful to those animals and plants that make calcium carbonate shells and tests. Corals are often identified as species who will exhibit major impacts, and whole ecosystems could be altered. However, shellfisheries will ultimately suffer as many shellfish, and in particular, mollusks (clams, scallops, oysters, conch, whelks) will have a hard time secreting their shells. They will experience mortalities, delayed metamorphosis, and even those that survive will likely be more vulnerable to predation. Coccolithophores, which are open ocean plankton and help contribute to the ocean carbon pump (whereby some of the CO2 is sequestered in the deep ocean basins due to the biological uptake by plants and their resultant death, coagulation, and settlement to the sea floor) may be lost.
Ultimately other fisheries will be impacted, even if they aren’t dependent upon calcification. As I have already mentioned, it will not just devastate reefs, although the colorful tropical playgrounds are often receive the most attention. It won’t just affect the calcifying reef-building organisms, or shellfish. It will affect all ocean life. Loss of reefs means a valuable fish habitat will disappear, and concomitant with that, many of the species which depend on those reefs to survive. If those species disappear, upper trophic levels will suffer, and already stressed by overfishing, may also start to disappear altogether. Likewise, many shellfish are not just commerically important to humans, but serve very specific ecosystem roles, perhaps most importantly, filtration and trophic transfer. Many bivalves will suffer, and these filter feeding organisms help clear the water column, depositing nutrients and food to organisms on the bottom, and transferring primary productivity up the food chain. Many fish either eat bivalves directly, or prey on things that eat the bivalves. In this way, these fish will also suffer.
Granted, I may be painting a doomsday scenario. But it is one that is a very real possibility. Yes, marine systems have shown incredible resiliency to a number of anthropogenic stressors. There are some marine calcifying organisms present today whose prehistoric ancestors lived and maybe even thrived in a higher acidity ocean. However, in geologic history, this acidification would have occurred over much more gradual timescales than its current pace, allowing organisms to adapt. That is the scary part. Unfortunately for organisms alive today, we are not affording them the opportunity to adapt because this change is so rapid. And since weak, bipartisan governments are unable to see the problem and do anything about it, and because the media portrays these issues as “controversial” and “debatable,” and because much of the public doesn’t understand the science (in part because we, as scientists, are often incapable of conveying concepts to general audiences in a manner that is easy to understand), we are living in a time where we COULD do something about it. But, sadly, we won’t do anything. And unfortunately, its entirely possible that our grandchildren or great grandchildren will only know of a coral reefs from photos or some old digital copy of Finding Nemo. That’s a same.
The Times article highlighted the problem. Now is the time to do something about it. Be more responsible and aware that the things we do affect the entire planet. Maybe , if WE ALL try, and contribute to solving the problem, ocean life as we know it may be spared. Here’s to hoping!