Isegoria

A Primeval Tide of Toxins tells a story that sounds like something out of a bad sci-fi flick:

The fireweed began each spring as tufts of hairy growth and spread across the seafloor fast enough to cover a football field in an hour.

When fishermen touched it, their skin broke out in searing welts. Their lips blistered and peeled. Their eyes burned and swelled shut. Water that splashed from their nets spread the inflammation to their legs and torsos.

“It comes up like little boils,” said Randolph Van Dyk, a fisherman whose powerful legs are pocked with scars. “At nighttime, you can feel them burning. I tried everything to get rid of them. Nothing worked.”

As the weed blanketed miles of the bay over the last decade, it stained fishing nets a dark purple and left them coated with a powdery residue. When fishermen tried to shake it off the webbing, their throats constricted and they gasped for air.

After one man bit a fishing line in two, his mouth and tongue swelled so badly that he couldn’t eat solid food for a week. Others made an even more painful mistake, neglecting to wash the residue from their hands before relieving themselves over the sides of their boats.

For a time, embarrassment kept them from talking publicly about their condition. When they finally did speak up, authorities dismissed their complaints — until a bucket of the hairy weed made it to the University of Queensland’s marine botany lab.

Samples placed in a drying oven gave off fumes so strong that professors and students ran out of the building and into the street, choking and coughing.

Scientist Judith O’Neil put a tiny sample under a microscope and peered at the long black filaments. Consulting a botanical reference, she identified the weed as a strain of cyanobacteria, an ancestor of modern-day bacteria and algae that flourished 2.7 billion years ago.

Even the reason for the fireweed comes straight from sci-fi:

Industrial society is overdosing the oceans with basic nutrients — the nitrogen, carbon, iron and phosphorous compounds that curl out of smokestacks and tailpipes, wash into the sea from fertilized lawns and cropland, seep out of septic tanks and gush from sewer pipes.

Modern industry and agriculture produce more fixed nitrogen — fertilizer, essentially — than all natural processes on land. Millions of tons of carbon dioxide and nitrogen oxide, produced by burning fossil fuels, enter the ocean every day.

These pollutants feed excessive growth of harmful algae and bacteria.

At the same time, overfishing and destruction of wetlands have diminished the competing sea life and natural buffers that once held the microbes and weeds in check.

The consequences are evident worldwide.

I feel like I should have heard some of these stories earlier:

Off the coast of Sweden each summer, blooms of cyanobacteria turn the Baltic Sea into a stinking, yellow-brown slush that locals call “rhubarb soup.” Dead fish bob in the surf. If people get too close, their eyes burn and they have trouble breathing.

On the southern coast of Maui in the Hawaiian Islands, high tide leaves piles of green-brown algae that smell so foul condominium owners have hired a tractor driver to scrape them off the beach every morning.

On Florida’s Gulf Coast, residents complain that harmful algae blooms have become bigger, more frequent and longer-lasting. Toxins from these red tides have killed hundreds of sea mammals and caused emergency rooms to fill up with coastal residents suffering respiratory distress.

North of Venice, Italy, a sticky mixture of algae and bacteria collects on the Adriatic Sea in spring and summer. This white mucus washes ashore, fouling beaches, or congeals into submerged blobs, some bigger than a person.

Along the Spanish coast, jellyfish swarm so thick that nets are strung to protect swimmers from their sting.

In First Ache, Annie Murphy Paul discusses infants and pain:

Twenty-five years ago, when Kanwaljeet Anand was a medical resident in a neonatal intensive care unit, his tiny patients, many of them preterm infants, were often wheeled out of the ward and into an operating room. He soon learned what to expect on their return. The babies came back in terrible shape: their skin was gray, their breathing shallow, their pulses weak. Anand spent hours stabilizing their vital signs, increasing their oxygen supply and administering insulin to balance their blood sugar.

“What’s going on in there to make these babies so stressed?” Anand wondered. Breaking with hospital practice, he wrangled permission to follow his patients into the O.R. “That’s when I discovered that the babies were not getting anesthesia,” he recalled recently.

Fortunately, Anand was able to approach the whole thing scientifically:

In a series of clinical trials, he demonstrated that operations performed under minimal or no anesthesia produced a “massive stress response” in newborn babies, releasing a flood of fight-or-flight hormones like adrenaline and cortisol. Potent anesthesia, he found, could significantly reduce this reaction. Babies who were put under during an operation had lower stress-hormone levels, more stable breathing and blood-sugar readings and fewer postoperative complications. Anesthesia even made them more likely to survive. Anand showed that when pain relief was provided during and after heart operations on newborns, the mortality rate dropped from around 25 percent to less than 10 percent.

In Kissing cousins, missing children, The Economist notes that a wider choice of mates reduces people’s reproductive output, and that may explain why families in rich countries are smaller than those in poor ones:

One of the biggest paradoxes in human biology is that as societies grow richer, people have fewer children. In most species, such an increase in available resources leads in the opposite reproductive direction. What makes the demographic transition, as this phenomenon is known, even more paradoxical is that in less developed times and places, the rich do not have smaller families than the poor.

Most explanations of the demographic transition are social. One school of thought emphasises reduced child mortality, suggesting this means that fewer “spares” need be generated to be sure that some children reach adulthood. Another points out that elderly people in rich countries do not depend on their children to look after them. A third suggests that as people are presented with more choices about how to spend their resources, they more often choose to consume things and experiences other than the joys and tribulations of parenthood. A fourth, somewhat more biological, posits that lavishing time and money on a few children, rather than spreading it around amongst many, produces adults who do better in the next-generation reproductive stakes. None of these ideas, though, is really satisfactory.

Now yet another explanation has been added to the pot. This is that the mixing-up of people caused by the urbanisation which normally accompanies development is, itself, partly responsible. That is because it breaks up optimal mating patterns. The demographic transition is thus, in part, a pure accident.

The science:

The study’s principal finding is that the most fecund marriages are between distant cousins. Using Iceland’s genealogical records, which allow the degree of relatedness between husband and wife to be calculated with great precision, Dr Helgason showed the optimum degree of outbreeding (measured in terms of the number of children and grandchildren produced) lay somewhere between cousins of the third and fourth degrees.

Probably, the reason is that marriages between close relatives risk inbreeding depression (caused by individuals receiving two copies of broken genes from the same ancestor, but by different paths — one maternal and the other paternal). Outbreeding means this is unlikely to happen, and at least one functional copy of each gene will be received. But outbreed too far and other difficulties arise as genetic incompatibilities between the parents make reproduction harder. (A well-known example is the case of rhesus blood groups, when the mother’s immune system may reject a fetus because of its father’s genes.)

The optimal degree of outbreeding remained the same in every 25-year generation since 1800, although the overall number of children from marriages of every degree of relatedness did drop gradually over time — an observation that accounts for part of Iceland’s demographic transition, and which probably has a social explanation. However, the level of outbreeding in Iceland has also increased markedly over that period, and Dr Helgason’s findings suggest that this, too, drives down average family size measured over the whole population by reducing the number of third and fourth cousin marriages.

Scientific American also ran a story on the study — under the questionable title, When Incest Is Best: Kissing Cousins Have More Kin.