KCAW.org | Katherine Rose |Â Jul 17, 2020
Predicting the future is hard, unless youâve got a crystal ball. In the basement of the Sitka Sound Science Center, a researcher has designed an experiment to study the future of ocean acidification, and her âcrystal ballâ is herring.
In Part 2 of KCAWâs two-part story on the 2020 herring season in Sitka Sound, Katherine Rose visits the lab of doctoral researcher Lauren Bell, as she explores possible futures for our oceans, and one of its most important resources.Â
Lauren Bell stands in about an inch of water, hovering over one of over twenty tanks in the basement of the Sitka Sound Science Center. The equipment used in this experiment is loud, and artificial sunlight bounces off Bellâs face as she tells me about the different types of seaweed sheâs growing.
âThe seaweed have grown a lot, theyâve been sitting in these conditions for about a month now,â she says.
Bell is a PhD student at UC Santa Cruz, and for the last couple of years sheâs been doing her research in the centerâs basement. Sheâs been trying to replicate what Southeast Alaskaâs waters will look like when our grandchildren are getting up there in age.
âThe projected change in Sitka Sound due to climate change, these added carbon emissions that are coming into our atmosphere, is that weâre going to see a gradual warming of our waters throughout the year,â she says. âAt any time of the year they expect that within 80 years weâre going to see about a a 7 degree increase Fahrenheit in water temperature.â
The excess carbon means nearby waters will become more acidic- the phenomenon known as âocean acidification.â
Bell uses hot tub heaters to simulate future temperatures and then bubbles in carbon dioxide, creating acidified water. Then researchers can put any marine organism from Sitka Sound into those conditions and see how they respond. This spring, they looked at two different kinds of seaweed.
âWeâre seeing how that impacts their growth, their productivity, how they photosynthesize in different light, their chemical defenses,â Bell says.
Seaweed may or may not do better under some of these conditions. She doesnât have results for this experiment yet- that takes a little while.
But last year, I visited her in the same basement, where she was monitoring herring roe to see how climate change could affect Pacific herring, and she now has the preliminary results from that study. Bell compared herring eggs from fertilization to hatch in four different conditions. She looked at how they were affected by warmer temperature, more acidic conditions, and water that was both warmer and more acidic. Bell found significant differences between herring eggs grown under those future conditions, and those grown in todayâs conditions.
âIt seemed like warming and acidification had very different impacts on actually what they looked like, how big they were and how well they could use their yolks,â Bell says. âAnd they had opposite effects.â
Bell says the fish that were exposed to only higher temperatures were shorter with larger yolks. And when you looked at ocean acidification they were actually longer with smaller yolks.
âSo clearly these two different things that are stressing them out are stressing them out in different ways,â she says.
But hereâs the really interesting thing: When Bell examined herring in future conditions, raised in both warmer temperatures and more acidic waters at the same time, the herring didnât look much different from the herring raised in todayâs conditions. Bell says it was like the two factors cancelled each other out. The fact that they were raised in harsher conditions was invisible to the naked eyeâŚand the scale.
But when you looked at them at the molecular level, at the RNA to DNA ratio, Bell says the eggs raised under future conditions were compromised.
âIt hides the fact that theyâre stressed because they almost cancel each other out, but theyâre still affected,â she says. âYou look at their molecular level, theyâre still not in good condition. Thatâs kind of terrifying. Like, okay, well maybe in the future look at them and we go âOh, theyâre fine, they look fine!â but actually if you look at their protein expression theyâre not functioning as well as they used to.â
Bell says she doesnât know exactly why the two factors would cause this reaction, but the effects are hard to ignore.
âThereâs something going on, theyâre stressed out, and we need to be very careful about what weâre using to determine how stressed they are in order to say whether theyâre going to be compromised in the future,â she says.
The Alaska Department of Fish and Game doesnât take the RNA:DNA ratio into account when itâs monitoring Sitkaâs herring population, although it does keep tabs on average weight and age classes. ADF&G biologist Sherri Dressel says the department takes climate change into account in its model by keeping tabs on temperature.
âIf temperature changes for a block of years and that affects herring survival, we are able to estimate a survival during blocks of similar temperature,â says Dressel. âIf there is long-term climate change, and the temperature continues to go up, this model allows us to estimate estimates, frankly of temperature over time.â
She says modeling takes ocean acidification into very broad account because there havenât been many studies of the effects of ocean acidification on Pacific herring. Sheâs excited to see Bellâs results.
âWith research like Lauren is doing- when we learn sort of the trigger points, or how ocean acidification affects certain life stages, then we may be able to incorporate it more effectively and more narrowly.â Â
Read or listen to more about Bell’s research on herring here.
Weâve been fishing and direct marketing our salmon since before Ronald Reagan stripped the solar panels off the White House roof. In those days, the roaring two-cycle 6-71 in our old gillnetter was still considered clean and efficient enough to power a working boat. We fought to prevent oil spills and to protect salmon habitat, and not long ago we switched most of our production from air freight to freezer barges to reduce costs and carbon pollution. But until recently, hardly anyone understood how heavily our family business â and the seafood industry as a whole â depends on protecting oceans and rivers from the rising consequences of pollution from burning fossil fuels.