Many of the threats currently facing our oceans, such as rising temperatures and pollution, are widely understood. However, there are a number of relatively unknown emerging issues that are poorly understood in terms of their potential impact, whether good or bad, on marine environments. Several are linked to the exploitation (开发) of newly in-demand ocean resources.

In the hope that early identification will support scientists, conservationists and policy-makers to address these new challenges in plenty of time, 30 experts in marine and coastal ecosystems have proposed a list of the 15 issues most likely to have a significant impact on ocean biodiversity over the next five to ten years. Here, we will take a closer look at one of those issues.

In coastal seas around the world, the water is growing darker. This darkness, caused by increasing amounts of sediment (沉积物) and nutrients, is a relatively little-studied phenomenon, but a potentially serious cause for concern.

A range of activities are responsible for coastal darkening. Rainwater runoff from agricultural land carries fertilizers, animal waste and sediment into rivers that march into the sea. Increasing rainfall and permafrost (永久冻土) melting (both the result of human-driven climate change) also cause sudden increases in ocean nutrient levels, leading to light-blocking algal blooms (藻华) . Digging and bottom searching stir up seafloor sediments.

Light influences marine life in a surprising number of ways. It passes through seawater, heating it and generating currents, and is absorbed by the large quantities of microscopic phytoplankton (浮游植物) upon which most marine life depends. Even moonlight, 400,000 times fainter than sunlight, is responsible for the nightly movements of many of the oceans’ tiniest inhabitants and, every year, hundreds of coral species spawn (产卵) at the same time, triggered by the light of a full moon.

As the clarity of seawater is reduced, light is prevented from entering the water column. At moderate levels, coastal darkening can have positive impacts, such as limiting coral bleaching (珊瑚白化) , but the benefits are few. Darkening could change species’ behaviour, distribution and even composition, profoundly altering their ecosystems and ability to store carbon. Poisonous chemicals such as methyl mercury (甲基汞) , which is broken down by sunlight, could spread higher up the food chain, reaching the fish that we eat.

Do you like cheeseburgers and French fries? How about dumplings or tacos? 【小题1】 That’s pretty much what you have to do these days when takeout food is delivered, since so many restaurants now close their bags with staples (订书钉).

【小题2】 We can rest confident that no one else has access to our meal before it arrives. But surely the use of tape (胶带), which many restaurants do choose instead, is much safer than staples. The latter are pulled into a bare and sharp position when a bag is opened, exposing lots of little teeth that find and surprise your wrist, hand or fingers. Ouch! Not to mention a wound from a staple is not only painful, but likely to get infected as well.

Furthermore, staples, being made of steel, are hardly environmentally friendly. And they pose yet another danger. 【小题3】 Believe me, you don’t want to eat a staple, especially not an open one.

What’s more, the open staple that we’re lucky enough to avoid when eagerly reaching into a bag of food poses a danger to anyone who handles the bag after we throw it away. 【小题4】

Why don’t we put an end to this practice and ensure that rice and bread remain our only “staple foods”, and not French fries?

【小题5】

Ever wonder how this season’s celebrations affect the environment? Guest blogger Krista Fairles takes an amusing look at this very topic:

The holidays are a wonderful, cheerful time when most people wait for Santa to bring them presents. But I’m not like most people. I spend my time wondering just what the environmental impacts of Santa Claus and his reindeer are, and more importantly, how I can calculate those impacts.

Lately I’ve been particularly curious as to whether Santa’s old sled is a clean green flying machine, or if he should be replacing his 8 reindeer with an environmentally-friendly car.

I should mention that, surprisingly, I was unable to find statistics specific to Santa’s magical flying reindeer, so these calculations use numbers from various sources and may not represent actual pollution caused by Santa and his animals. In other words, don’t complain to the government about the damage Santa is causing to the environment based on this article.

Santa’s yearly trip around the globe is 44,000km long, twice the average of a North American driver. If we assume that the magic provides the altitude for this trip, then reindeer power only needs to push Santa’s sled forward. To complete the trip in 12 hours, I estimate they must travel at a speed of about 3100km/h. To travel at this speed, for this length of time, the reindeer need to eat an incredible 980 million calories each!

So the next question is: how much food is in 980 million calories? Well, if they’re eating corn, they’d need to eat 16,500 lbs each - or 1.6 acres of food. Growing 12.8 acres of corn has its own implications for the environment that we’ll leave for another calculation.

We now need to consider that during the global trip the reindeer are “letting out” some of that corn in the form of methane (甲烷，沼气). A resting cow produces 110 kg of methane per year, so flying reindeer would each let out about 4.8 tons. With methane causing 20 times the global warming damage of CO2, and the altitude increasing that damage by 1000% that another 20 times, we can put Santa’s round-trip emissions at 15,488 tons. This is much more than the 100 tons an environmentally-friendly car would release on the same trip!

Bad Santa.