Plastics, more importantly microplastics, clog our oceans. This phenomena in the ocean has been likened to smog around cities. These plastic particles are dangerous because they can absorb toxins, subsequently be consumed by zooplankton and invertebrates, and bioaccumluate up the food web to fish that are consumed by humans. A study in Nature found that 25 percent of seafood sold contains microplastics! There has been a recent awareness of the unseen harm that exists when plastic pollution in the ocean degrades into microplastics. A report in Environmental Research Letters estimated that “accumulated number of micro plastic particles… ranges from 15 to 51 trillion particles, weighing between 93 and 236 thousand metric tons.” That is cray cray. Despite a better awareness of the impact of microplastics on marine ecology, we still have a poor spatial understanding of microplastics in the ocean. The presence and density of microplastics is determined by trawling the ocean (i.e., researchers go out with a net and physically count the pieces of plastic they pick up). As you can imagine, this is not very effective.
Most people have heard of cone snails. They are the genus of venomous marine snails that shoot a poisonous “dart” (hypodermic-like modified radula tooth attached to a venom gland) to attack and paralyze their prey before feeding on it. Smaller cone snails primarily hunt and prey on marine worms, while the larger ones hunt fish. To humans the sting of a smaller cone snail is similar to that of a bee, but contact with larger cone snails can be fatal! Basically they are the badasses of the snail world.
After years of scaring pregnant women away from fishy nutrition, the FDA is finally updating its recommendations to encourage them to eat 8-12 ounces of low-mercury fish a week. That’s 2 or 3 meals per week in order to support fetal growth and development. Curious about what fish are low mercury? Stay away from tilefish from the Gulf of Mexico, swordfish, shark, and king mackerel and limit albacore tuna to 6 ounces a week. Better options include “some of the most commonly eaten fish such as shrimp, pollock, salmon, canned light tuna, tilapia, catfish, and cod”. For locally caught fish, you should check with your local authorities. The new recommendations aren’t final – read the draft and write in if you want more information that would help you make safe and healthy seafood choices. Here’s some things you should consider. Read More
Happy Fun Science Friday!
Though this post does not present such a happy story, given the recent discussion about dolphin photobombing, this week’s FSF is topically related. In the spring of 2010 the Deepwater Horizon oil rig experienced catastrophic failure resulting in the worst oil spill in human history. The Gulf of Mexico (GoM) was the unfortunate host of this catastrophe and the GoM community is still feeling the ecological, social, and economic consequences of this disaster.
One such impact that received little TV coverage during the spill was the uncharacteristic spike in dolphin deaths. A few months following the BP spill there was an unprecedented spike in dead dolphins washing ashore along the Gulf Coast; 67 dead dolphins by February of 2011, with more than half (35) of the dead dolphins being calves. This is in stark contrast to years preceding the spill when one or two dead dolphins per year were normally documented to wash ashore. Despite the spike in dolphin deaths, there was no definitive evidence linking the dead cetaceans to the oil spill as a number of other factors could have been responsible for the deaths, including infectious disease or the abnormally cold winter proceeding the spill.
As part of my ongoing community-based research on water quality in coastal North Carolina, I ended up tasked with answering what I thought would be a very basic question: what is the predominant pesticide used in my county? The largest farm and by far the largest amount of cropland is occupied by a traditional corn/soy rotation with the occasional cotton thrown in. Given the multitude of American acres donated to corn/soy, I figured I could easily find out the basics of that crop’s chemistry. Not so. My little information adventure has made me realize why there are so many rumors surrounding farming’s impact on water quality in the region. Rumors are easier to find than facts.
There are currently more than 7,500 offshore oil platforms actively probing the earth’s crust for black gold. Their relatively minimal appearance at the surface belies the shear magnitude of human construction beneath the waves. Oil platforms are among the world’s tallest man-made structures. Compliant tower platforms reach up to 900 meters in depth (in contrast, the tallest building is 828 meters). these rigs are not permanent structures. As the wells run dry and sea water corrodes steel jackets, the wells are capped and rigs decommissioned. At least 6500 offshore platforms are slated for decommission by 2025, which begs the question, what do we do with inactive oil platforms?
Overfishing is most often implicated as the cause of decreasing fish stocks and that makes a lot of logical sense if you’ve ever seen a large commercial trawler unload its catch. But there very well might be another force at work in the precipitous decline in fish stocks worldwide: pollution. The basic premise is that it takes resources to deal with pollutants that normally would be given to growth and reproduction. Through polluting the ocean, we have selected for the fish individuals that can most effectively divert those resources, inadvertently also selecting for smaller fish that reproduce less. That has huge implications for the fish’s population dynamics and potentially total fish stock. More details below the fold…
The following photos are from a massive fish kill in a river close to la Guillec, France. According to Dr. Sophie Plouviez, the die-off affected not only fish, but nearly all of the benthic invertebrates in the river. The cause of the die-off has yet to be determined. We are trying to locate the source of the images, and will continue to update as more information become available.
We recieved several responses to Dave’s post this week on the bizarre “Save the Light Bulb” movement. A movement that seeks to ban energy efficient compact fluorescent lights (CFL) and return to the old, energy expensive, incandescent bulbs. The primary critique is that CFL’s contain mercury, and thus, any environmental benefit is negated by mercury exposure when the bulbs break or are thrown out.