Makin’ Babies on the Beach

Being a nomadic academic, I’ve found social media sites to be incredibly useful for keeping up with all the folks who would have been lost to migration, following the global tidal flows of scientific funding. Friends who’ve disappeared into the Australian outback or the corn fields of Indiana, remain close in my heart and in my mind, as their constant updates keep me abreast of all their life’s trajectories. Through Facebook, I’ve helped them crowdsource answers to life’s bigger questions: should I order the eggs benedict or the Belgian waffles? Where is the best place to live in DC? Was that a poisonous snake that just bit me?

Intermixed with these deep scientific engagements, are the regular going-ons of people’s lives: dating, marriages, divorces, marriages, divorces and marriages again, are all documented in great detail. I follow the wave of news, like and comment as appropriate and am always fascinated by where everyone landed. It has always been a positive experience. That is, until people started having children…then things went from very sweet to very gross.

First, there were the clever confessions (“Ruby is going to have a cousin!”), the indistinguishable ultrasounds, the cute baby bumps. Adorable. Then came the strangely awkward posts from the delivery room, the sweaty slightly mangled expressions of the new parents, the confused babies with misshapen heads. All of this seemed appropriate, if not a little too share-y.

Appropriate that is, until we got to the poop. Yes, there is nothing new parents want to share more with everyone in the world then all about their little lamb’s excretions. And it’s not limited to poop mind you. There is vomit. Urine. Mucus. Really anything that can be projected from their lovely little squirts will turn up on my Facebook newsfeed.

It was highly educational. I learned about consistency. I learned about regularity. I learned about colors and shapes. I learned about prunes over apples. Yes, as soon as you become a parent, the most exciting thing in your life changes from playing games of hide the salami to trying to desperately keep the salami from spraying out of your small child’s digestive tract while at Bloomingdales fine whites sale. Exciting? No doubt! Enticing? Hardly.

So it seems that my friends have become fecund in their old age….and are willing to brag about all the ins and outs of what that means (though mostly it really is just the “outs”). I shouldn’t complain, my friends are quite lucky. Not all animals will be having the same reproductive success, and in fact, under climate change some animals may be in need of a little love intervention….

Take the mellow sea urchin for example. These spiny little creatures are in for some trouble under ocean acidification. As a reminder, ocean acidification is a pH change of the ocean caused by the increase of carbon dioxide in ocean water (this video explains it well). I’ve talked about ocean acidification several times before. How it could drive clown fish into the arms of predators (and their parents, ew), how it will ruin hermit crabs ability to find an ideal home (in this market? Unfair!)….but I haven’t talked about how it will ruin the sex lives of sea critters. And that is a sincere possibility.

What do I mean? Well, the sperm of sea urchins hangs out in an immobilized state inside the acidic environment of the testis, waiting to be released (yes sea urchins have testis, get over it. They also have sex, don’t freak out.). It turns out that the release of the sperm from the acidic environment into the less acidic sea water “wakes up” the sperm and gets them swimming. So you can see the problem with more acidic sea water, those sperm just won’t wake up. So less motile sperm could lead to less reproduction and then, you know, no adorable little sea urchins to Facebook about (1).

So are things doomed for the noble little sea urchin? Maybe not.

Why? Selection!!!

What do I mean? Well it seems that though many sea urchins experience reduced sperm motility in more acidic ocean waters, some are minimally affected. As in, there is variation between individuals (2). Therefore the individual with sperm that remains motile under the more acidic conditions will get to make more of the babies. In theory anyway.

So, maybe a little bit of evolution could come in and save the day for sea urchins. Or maybe not while there seems to be some sperm that can manage in more acidic environment, we know less about the larvae and developmental stages of sea urchins. So one question down, about 500 more to go….

In the meantime, we can hold out hope for those little urchins. Maybe we should try to figure out if this species will have the ability to adapt and survive. Maybe we should study the impacts of ocean acidification on the different life stages of these critters. Or maybe we should just encourage them to talk about it on Facebook. Why not? It seems like when it comes to reproductive success, you can never overshare.

Further Reading:
(1) Near-future levels of ocean acidification reduce fertilization success in a sea urchin
(2) Individual Variability in Reproductive Success Determines Winners and Losers under Ocean Acidification: A Case Study with Sea Urchins

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