The Health of the Oceans Series

The ocean is my greatest passion and I remember always having a deep and intrinsic love for the dynamic blue water which covers 2/3 of our planet. The ocean has provided me with a sense of connection, courage, intense joy and a deeply fulfilling livelihood and career. I want to give back, and this blog is my platform. In it, I aim to celebrate the oceans’ flora and fauna, educate readers about what is happening in the oceans and provide both inspiration and tools for change.

My next series of posts will discuss what I believe are the greatest threats to the health of the oceans, and potential solutions. Algae (includes seaweeds) are celebrated for their starring role in the health of the oceans and their potential to be an important part of the solutions to problems facing the oceans today. I begin The Health of the Oceans Series with the issue of climate change.

#1: The Oceans and Climate Change, Starring Algae

*Note: The word algae (singular alga) is a comprehensive term that includes both microalgae and macroalgae. Seaweed is a colloquial term that refers to macroalgae only.

CO2 Absorption and Ocean Acidification

The oceans play a critical role in regulating climate and keeping global temperatures down. They absorb most of the excess heat (an estimated 90% or more) caused by greenhouse gases. Marine algae absorb an estimated 1/3 of atmospheric carbon dioxide, the most prevalent greenhouse gas aside from water vapour. Unfortunately, the absorption of excess carbon dioxide currently in our atmosphere is causing changes to the chemistry of the ocean, including increasing acidity and an associated decrease in carbonate ions which many marine species depend on for survival. This process is called ocean acidification. While scientists are just starting to uncover the myriad effects of ocean acidification, we know that it is having a negative impact on many marine organisms and that calcareous organisms, those with a large component of calcium carbonate, are especially sensitive. Of particular concern with regards to climate change is the negative effect on coccolithophores, a very abundant group of calcareous microalgae which play a major role in biogeochemical cycles critical to the regulation of global climate. Other organisms known to be negatively affected by ocean acidification include echinoderms (starfish), cnidarians (coral), crustaceans (crabs and shrimp), mollusks (shellfish) and fish. Macroalgae, or seaweeds, have an alkalizing effect on their surrounding waters, just as they do in our bodies, and can positively influence the pH of the water where they grow. For this reason, there are already oyster farmers who are growing seaweeds in order to lower acidity and improve water quality in their oyster farms. Oysters and other shellfish are particularly sensitive to small increases in acidity.

Kelp Forests and Warming Oceans

Kelps are brown macroalgae which belong to the order Laminariales. They are the largest seaweeds in the world and provide structure and primary production to temperate coastal ocean ecosystems. The Pacific Northwest is home to 30 species of kelp, more species than anywhere else on the planet. The two largest species of seaweed in the world, bull kelp (Nereocystis luetkeana) and giant kelp (Macrocystis pyrifera), form the canopy of the stunningly beautiful kelp forests of the Pacific Northwest. Kelp forests and kelp beds have among the highest rates of primary production of any ecosystem in the world and grow along 25% of the world’s coastlines (Wernberg et al., 2019). They are currently in a global state of decline at an estimated rate of approximately 2% annually (Wernberg et al., 2019). Kelps require cold water in order to grow and a temperature increase of only 1°C can affect their ability to reproduce. At the Phycological Society of America’s 2018 meeting held at the University of British Columbia in Vancouver, Canada, I listened to a number of kelp phycologists say that their research points to warming ocean temperatures as the most significant driver of the global decline of kelp forests.

Marine Heatwaves

Extreme weather events are occurring more often as a result of global warming. Marine heatwaves (MHWs), defined as a specific area of the ocean that experiences abnormally warmer than average temperatures over a relatively short period of time, are increasing in size, frequency and intensity, with catastrophic effects on marine ecosystems. The longest lasting and largest MHW occurred in the northeast Pacific Basin. It covered a massive swath of the northeastern Pacific, extending from Alaska to Baja, Mexico. With some estimates in excess of 4 000 000 km2, its size dwarfed all other MHWs on record. Known as “the blob,” it was first detected in 2013, persisted to the end of 2015 and appeared to dissipate in 2016. The blob caused unusual weather on the west coast of North America and disrupted all coastal ocean ecosystems in its range, affecting every level of the food chain. Populations of fish, marine mammals, seabirds and other marine life were devastated due to the blob’s nutrient poor water and the arrival and subsequent competition of new, warm water species. Huge areas of kelp forests, primary producers for most of the coastal ecosystems affected by the blob, were wiped out, and have yet to return. Compared with other seaweeds, kelps are particularly sensitive to increases in water temperature. For example, bull kelp, a critical canopy species of the kelp forests of the Pacific Northwest, is normally one of the most fecund seaweeds in the world. However, when bull kelp is growing in its upper temperature range, an increase of 1°C can significantly affect its ability to reproduce and an increase of 3°C can render it unable to reproduce. The average increase in sea surface temperatures inside the blob was 2.5°C. The warmer water temperatures also created the perfect conditions for toxic algae blooms, which became more prevalent. Alarmingly, an MHW similar to the blob appeared in the same area of the northeastern Pacific Basin in 2019.

Livestock, Methane Production & Seaweed

Raising livestock on an industrial scale is among the top contributors to global warming. It has a negative impact on climate change in the following ways: deforestation, to create pastures for livestock; the production of nitrous oxide (which has an estimated warming effect 265 times higher than carbon dioxide) from the use of fertilizers on feed crops; methane production (which has an estimated warming effect 25 times higher than carbon dioxide) released by ruminants during digestion and from their manure; transportation; processing and farm operations.

In the early 2000s, Joe Dorgan, a Canadian farmer from the island province of Prince Edward Island, noticed that his cows who had access to the seashore appeared healthier and produced more milk than his inland herd. He wondered if the nutrient-rich seaweed they grazed on was the cause and so he started collecting washed up seaweed and feeding it to his inland herds. Dorgan began to notice the same effect on his inland cows: they seemed healthier and produced more milk. He believed using seaweed as an additive in livestock feed, as it has been used traditionally for thousands of years, could have potential as a business and wanted to quantify the benefits of seaweed to grazing livestock. Rob Kinley, at the time a research scientist at Dalhousie University, studied Dorgan’s seaweed-consuming cows and discovered that not only was seaweed increasing the efficiency of the cows’ digestion, but it was also significantly decreasingmethane production. The energy saved allowed for more to go toward milk production, which increased. Kinley, who quantified the decrease in methane production at 12%, wondered if different species of seaweed might have an even greater effect on methane production. With this in mind, Kinley teamed up with phycologists and ruminant nutrition experts in Australia, where an estimated 10% of all greenhouse gas emissions is methane produced by livestock. The research team discovered that the red seaweed Asparagopsis taxiformis had exceedingly dramatic effects on methane output. In vitro studies showed a 95% reduction in methane output with 5% seaweed administered (Roque et al., 2019). In a study on live sheep, methane output was reduced in a dose-dependent manner with up to 80% reduction with 3% seaweed (Asparagopsis taxiformis) added to the diet compared with the control group receiving no seaweed (Li et al., 2016). An estimated 44% of greenhouse gas emissions from raising livestock is methane, with livestock-related emissions making up approximately 14.5% to 18% of global greenhouse gas emissions.

Biofuels & Algae

Biofuels, fuels made from oil-containing plants, have been proposed as an alternative to the burning of fossil fuels, which accounts for an estimated 65% of global greenhouse gas emissions. Currently, corn and soy are the major sources of biofuels. The downside to using corn and soy is the amount of arable land, clean water and production that goes into growing these crops, which includes significant greenhouse gas emissions. Microalgae can also be used as a biofuel. There are substantial advantages associated with the use of microalgae as a biofuel: they are not a food crop of humans and livestock, they can be grown on a relatively small area of non arable land and can be grown using agricultural wastewater containing chemical fertilizers and other agricultural contaminants. This redirection of contaminated water, which is then purified by the microalgae, helps to prevent pollution of rivers, lakes and coastal waters. Additionally, microalgae require few nutrients, grow much faster than conventional crops and have a higher oil productivity than all other current oil crops. The following fuels have been produced with microalgae: biodiesel, biobutanol, biogasoline, methane, ethanol, green diesel and, particularly encouraging, jet biofuel. The Carbon War Room (CWR), an international non-governmental organization and think tank working on market-based solutions to climate change, calls sustainable aviation fuels “the most challenging emissions reduction opportunity” as well as “the greatest potential for achieving carbon-neutral growth in aviation” (Hawken, 2017, p. 151).

In Summary

Climate change is the most imperative environmental issue of our time. Like land-based ecosystems, ocean ecosystems are being negatively impacted by climate change. Algae play a critical role in the regulation of climate, exerting an essential cooling impact on global temperatures. They sequester carbon and absorb large amounts of the greenhouse gas carbon dioxide. Macroalgae (seaweeds) can help lower the acidity of their surrounding waters caused by an excess of carbon dioxide in the atmosphere. Moreover, algae are a key source for innovations aimed at combatting climate change.

Seaweeds sequester large amounts of carbon, absorb carbon dioxide and produce oxygenPhoto Credit: Amanda Swinimer — Seaweeds sequester large amounts of carbon, absorb carbon dioxide and produce oxygen
Photo Credit: Amanda Swinimer

Positive Impactful Actions

*Reduce your carbon footprint

~Green your commute: ride a bike, walk, carpool, hybrid/electric car

~Use less energy at home

~Make sure your investments are green

~Eat a climate friendly diet: local foods, less meat and diary

~fly less

~when you consume, support climate friendly businesses

*Vote for people who have a robust plan for fighting climate change at the municipal, provincial and federal levels

*Have conversations with people about climate change and solutions

*Support groups and initiatives that combat climate change

References

Cornwall, Warren. Ocean heat waves like the Pacific’s deadly ‘blob’ might become the new normal. Science; 2019. https://www.sciencemag.org/news/2019/01/ocean-heat-waves-pacific-s-deadly-blob-could-become-new-normal

Hawken, Paul. Drawdown: The Most Comprehensive Plan Ever Proposed to Reverse Global Warming. Penguin Random House LLC, New York, N.Y., 2017.

Kinley, R., de Nys, R., Vucko, M., Machado, L., Tomkins, M., 2016. The red macroalgae Asparagopsis taxiformis is a potent natural antimethanogenic that reduces methane production in vitro fermentation with rumen fluid. Animal Prod. Sci. 56, 282. http://dx.doi.org/10.1071/AN15576.

Li, X., Norman, H., Kinley, R., Laurence, M., Wilmot, M., Bender, H., de Nys, R., Tomkins, N., 2016. Asparagopsis taxiformis decreases enteric methane production from sheep. Animal Prod. Sci. 58. http://dx.doi.org/10.1071/AN15883.

Roque, B., Brooke, C., Ladau, J., Polley, T., Marsh, L., Najafi, N., Pandey, P., Singh, L., Kinley, R., Salwen, J., Eloee-Fadrosh, E., Kebreab, E., Hess, M., 2019. Effect of the macroalgae Asparagopsis taxiformis on methane production and rumen microbiome assemblage. Animal Microbiome 1. https://doi.org/10.1186/s42523-019-0004-4.

Thomas Wernberg; University of Western Australia; presentation at the 5th joint meeting of the Phycological Society of America and International Society of Protistologists, Vancouver, B.C. 2018.

Wernberg, T., Krumhansl, K., Filbee-Dexter, K., Pedersen, M., 2019. Status and trends for the world’s kelp forests. World Seas: An Environmental Evaluation, edition 2, chapter 3, Publisher: Elsevier, 57-78. http://dx.doi.org/10.1016/B978-0-12-805052-1.00003-6.

Zilliac, Chloe. Return of the Blob: Marine Heat Wave Wreaks Havoc in the Pacific. Sierra Magazine, 2019. https://www.sierraclub.org/sierra/return-blob-marine-heat-wave-wreaks-havoc-pacific.