Welcome back to SciShow Breaking News, I'm Hank Green.

Another reason I did this show is because science helps us understand and therefore appreciate the world a whole lot more. But of course not everything that science does is exactly peppy, sometimes it turns up stuff that makes me feel a little bit Grumpy Cat. 

Take for example, poison fog. Toxicologists in California announce yesterday that fog along the Pacific coast of the United States contains surprisingly high levels of mercury. The team from UC Santa Cruz actually found that fog is probably more responsible for soil contamination in California than rain is. They're not totally sure how it's happening, but they think it has to do with deep ocean currents that rise to the surface off the coast of California. This upwelling brings with it much of the ocean's mercury content which mostly comes from burning fossil fuels on land. When the water evaporates, the mercury in it breaks down changing from a more stable form to what's called methyl mercury which is both more toxic and more readily absorbed by plants and animals. The researchers think that this fog may be messing with California's famous old growth forests and could explain why mercury is showing up in insect populations there. If you want to learn more about mercury and other kinds of pollution we've just wrapped two episodes of CrashCourse Ecology about all the ways humanity is dorking up the biosphere, you can watch those starting January 7th.

Here's another thing that made my 16-bit flower droop a little bit, dropping sperm counts. The largest ever study of male fertility was released yesterday, and it found that both the concentration and quality of sperm in men decreased dramatically from 1989 to 2005. A research team based in France studied nearly 27,000 French men and found that over 17 years, the average concentration of sperm and the average amount of healthy sperm they produced declined by 33%. This means that statistically speaking, fewer men were fertile in 2005 than in 1989. And just like with the mercuric fog, the researchers don't know exactly what's causing it. It could be caused by environmental factors like endocrine disruptors, the chemicals that create all those hermaphroditic frogs that you've heard about, or it could have to do with epigenetics, the way environment and behavior can influence how your genes behave. Now the researchers say that their findings in France don't necessarily reflect fertility levels in the rest of the world but presumably this will mean that France will produce fewer people like Marion Cotillard and that can't be a good thing.

Finally, you've probably already heard this but I wanted to make sure that you heard it correctly, NASA's Mars science laboratory has not found any organic molecules in the Martian soil. After that head-fake last week about earth-shaking findings coming from the MSL's Sample Analysis at Mars instrument, the rover's science team clarified on Monday that it found lots of interesting stuff in its first samples collected, including water, volcanic glass, and the chlorine and oxygen compound perchlorate, but no amino acids or any other potential building blocks of life. While one experiment conducted by SAM did seem to yield a methane compound, scientists think it may have been the result of Martian chlorine reacting with Earth-bourne carbon that was still inside the instrument. So despite what you may have heard, SAM's principal investigators said on Monday we have no definitive detection of Martian organics at this point. Still, don't let this week of news bum you out, I'm sure that the coming weeks will bring plenty of hope from the Curiosity rover, California, and Frenchmen everywhere, as well as the rest of us. 

Thank you for watching this episode of SciShow Breaking News, if you want to keep up to date on all of the latest breaking science news throughout the world you can go to youtube.com/scishow and subscribe.