With their sapphire-tinted claws, their olive green shell, and their paddle-shaped rear swimming legs, blue crabs are easily recognizable. They’re famous not only for their looks, but also for their telltale scientific name (Callinectes sapidus), which translates roughly to “savory beautiful swimmer.” Indeed, they’re prized for their tender meat and sweet, delicate flavor and are, not surprisingly, the most heavily harvested crustaceans in the geographical areas in which they live. They’re found in brackish coastal lagoons and estuaries from Nova Scotia, through the Gulf of Mexico, and as far south as Uruguay. Notably, they’re considered the Chesapeake Bay’s signature crustaceans. Continue reading →
Overexploitation—the unsustainable use of natural resources—is one of the greatest pressures that human populations force upon ecosystems worldwide. Overfishing, a type of overexploitation based on “catching too much fish,” contributes to the well-established decline of fish stocks.
According to the Food and Agriculture Organization of the United Nations (FAO), globally, the fraction of fish stocks that are within biologically sustainable levels has exhibited a decreasing trend, from 90.0 percent in 1974 to 66.9 percent in 2015. Further compounding this, the percentage of stocks fished at biologically unsustainable levels increased from 10 percent in 1974 to 33.1 percent in 2015, with the largest increases in the late 1970s and 1980s, and a slight decline in 1996. However, a study published in 2016 shows that we catch much more fish than estimated by the FAO. Daniel Pauly, lead author of the study, told The Guardian: “Our results differ very strongly from those of the FAO. Our results indicate that the decline is very strong and is not due to countries fishing less. It is due to countries having fished too much and having exhausted one fishery after another.” Continue reading →
What’s in soil? Water, air, sand, silt, clay, and organic matter. What’s in organic matter? Humus, earthworms, insects, bacteria and, we just learned, giant viruses. As their name implies, these viruses are big—their dimensions and genome sizes are comparable to those of bacteria. Continue reading →
Can you imagine our beautiful planet becoming a “plastic planet”? In the BBC documentary film Blue Planet II, members of the producing team noted that plastic waste is ubiquitously floating in the sea, including fishing lines, plastic packages, and plastic bottles. Marine organisms can be trapped by plastic waste that is everywhere in the oceans, even in the deepest and most remote parts. So it is essential to carry out intensive studies of plastic waste. Large plastics can either be physically or chemically broken into fragments after having been in the water a long time, traveling long distances. Such fragments, coupled with ones that were released into seas as fine plastic particles (smaller than 5 mm), are collectively called microplastics.
Surface water trawling for floating microplastic collection on the Pearl River estuary in China. Inset pictures are pieces of microplastic (fragments, pellets, and lines) from the trawl. Credit: Lei Mai.
The Gaviota Coast in southern California is a precious resource to people and wildlife; a scenic stretch of coastline home to a wealth of biota, sand beaches, intact habitats, and natural drainages that allow the undisturbed flow of water between land and ocean. On 19 May 2015, eyes around the world turned to this stunning stretch of coastline, as newspapers and television screens flashed images of crude oil seeping into the waters of the Santa Barbara Channel. Continue reading →
The following post is one of a series previewing the research that will be presented at the SETAC Europe Annual Meeting in Rome, Italy (13-17 May 2018).
A guest post by Gemma Giménez Papiol
How do toxic natural compounds such as microalgae toxins or plant secondary metabolites affect water quality, ecosystem functioning, and human health? For the majority of natural toxins—of which there are at least 25,000 different compounds—we do not know! Natural toxins include some of the worlds’ most toxic substances. Continue reading →
For millennia, human societies have altered river flows in different ways. In the 20th century, the impact of human activities on rivers and watershed environments has increased exponentially—and engineering works such as channelization and dam construction have created new, complex, hybrid human-natural systems. Continue reading →