How Does Ocean Acidification Affect the Food Chain? New Research Shows Impacts on Coccolithophores

Posted on January 6, 2023January 6, 2023 by Team Writer

coccolithophores - how ocean acidification affect food cain — Magnified coccolithophores
Source: UCLA|Photo via hhmi.org

Increases in ocean acidity are damaging the first link in the food chain, a microorganism called coccolithophores. This is causing major impacts to marine species that rely on coccolithophores as their primary source of food.

Recent research from the Universitat Autonoma de Barcelona’s Institute of Environmental Science and Technology illustrates how ocean acidification is affecting coccolithophores, and thus, how ocean acidification is affecting the food chain as a whole.

Background Information: What is Ocean Acidification?

Full Study: Nutritional response of a coccolithophore to changing pH and temperature (Association for the Sciences of Limnology and Oceanography (ASLO) Aug 2022).

How Ocean Acidification Decreases the Nutritional Content of Coccolithophores

microscopic coccolithophore - ocean acidification affect food chain — Source: UCSC Earthguide

Coccolithophores, part of the phytoplankton family, are single-celled plant-like marine microorganisms that are commonly found close to the surface of the ocean. Despite their microscopic size, coccolithophores play an important role in the marine food chain by serving as its foundation. Many small marine animals rely on coccolithophores as their primary source of food and energy. Even small fish and other organisms that do eat other things, like worms or small crustaceans, feed on coccolithophores when other sources of food are scarce. Marine animals obtain nutrition and energy from coccolithophores’ fat content, known as lipids.

Coccolithophores build protective scale-like platings around themselves known as coccoliths (the oval platings shown in the image to the right). These coccoliths are made of limestone (calcite). However, ocean acidification makes it much more difficult for organisms to build calcite shells.

A 2022 study conducted by researchers from the Universitat Autonoma de Barcelona’s Institute of Environmental Science and Technology, in collaboration with the Roscoff Marine Station of France, discovered that ocean acidification has significantly reduced coccolithophores’ ability to build shells, and decreased the nutrient content in their bodies. This has massive cascading effects throughout the food chain. Here’s what you need to know about it.

The researchers created a simulation of future climate conditions, causing ocean warming and triggering ocean acidification.
At first, the coccolithophores showed resilience to the increase of ocean temperatures and acidity. The researchers even observed an increase in their population.
As the experimental ocean acidity spiked, the researchers found that coccolithophore population growth halted as the organisms began to struggle to build their shells. The acidic conditions caused the coccolithophores’ protective platings (coccoliths) to collapse. While this may seem beneficial to organisms that eat coccolithophores (because this makes them easier to eat and digest), this breakdown of their shells comes with other negative consequences.
Researchers also discovered that when coccolithophores were exposed to acidified ocean conditions, the nutritional content in their bodies significantly decreased. As acidification worsens, this reduced nutrient content may have a detrimental impact on the food chain. Marine species that rely on coccolithophores for food, such as smaller fishes and zooplanktons, would be forced to feed on nutritionally deficient food.
Researchers concluded that as ocean acidification affects coccolithophores’ energy and nutrients, coccolithophores may also seek lower-acidity areas to try and slow ocean acidifications’ effects on their survival. This movement will pose an extra threat to marine species that rely on coccolithophores for food, as some may be unable to “follow” coccolithophores to lower-acidity conditions..

The images below show the comparison of healthy coccolithophores (a) and collapsed coccolithophores due to ocean acidification (b).

healthy coccolithophore- how ocean acidification affect food chain — Healthy coccolithophores
(Source: © Phys Org)

collapsed coccolithophore - - how ocean acidification affect food chain — Collapsed coccolithophores
(Source: © Phys Org)

Sources:

“Ocean warming and acidification impact marine food web” Universitat Autonoma de Barcelona, Nov 2022

https://www.uab.cat/web/newsroom/news-detail/ocean-warming-and-acidification-impact-marine-food-web-1345830290613.html?detid=1345875011926

“Ocean warming and acidification impact the marine food web, study finds” Phys Org, Nov 2022

https://phys.org/news/2022-11-ocean-acidification-impact-marine-food.html

“Nutritional response of a coccolithophore to changing pH and temperature” Association for the Sciences of Limnology and Oceanography (ASLO) Aug 2022

https://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lno.12204

Researchers Discover How Ocean Animals Adapt to Ocean Acidification – But Adaptation Comes at a Price

Posted on September 15, 2022September 15, 2022 by Team Writer

As climate change-driven ocean acidification and higher ocean temperatures continue to threaten various marine animals, some species are beginning to evolve in order to adapt to warmer, more acidic conditions. But does this evolution come at a price? A recent experiment from the University of Vermont, in collaboration with the University of Connecticut, the GEOMAR Helmholtz Center for Ocean Research in Germany, and the University of Colorado, Boulder, focuses on this question.

This March 2022 study analyzed how one copepod (a small crustacean species), Acartia tonsa, will likely evolve in order to adapt to warmer ocean temperatures and higher levels of carbon dioxide. However, these copepods’ resilience to climate change comes hand in hand with increased vulnerability to other stresses such as limited food sources.

Background Information: What is Ocean Acidification?

Full Study: Loss of transcriptional plasticity but sustained adaptive capacity after adaptation to global change conditions in a marine copepod (Brennan et al. 2022)

How Copepods Adapt to Ocean Acidification

acartia tonsa - ocean animals adapt ocean acidification — *Acartia Tonsa*
*Source:* *UC Davis*

Scientists from the University of Vermont conducted a laboratory experiment to understand the effects of ocean acidification on copepods, a group of small crustacean species that serve as a food source for many marine species. Copepods also act as an important biological control agent against mosquitos carrying human diseases.

Researchers artificially evolved 23 generations of Acartia tonsa, a copepod species, in order to study the effects of ocean acidification on copepod reproductive success. The results reveal that copepods can adapt fairly quickly to a warmer, acidified ocean ecosystem, but that this rapid evolution decreases the species’ genetic flexibility, which leads to increased vulnerability to other stresses.

Finding One: Copepods have the ability to quickly adapt to ocean acidification due to high genetic flexibility.

Copepods have the ability to become sexually mature and reproduce in just four to six weeks, making them a helpful organism to help scientists study evolution over shorter periods of time. This study utilizes copepods’ ability to reproduce and create new generations in a short period of time to analyze the effect of ocean acidification and warming on the health and reproductive success of twenty-three generations of copepods.
Scientists created an ecosystem that simulates future ocean conditions under climate change. They exposed thousands of copepods in multiple generations to the acidic environment and tracked their health and reproductive ability.
The study found that copepods showed resistance to ocean acidification and continued to thrive throughout twenty-three generations. This is due to copepods’ plasticity (genetic flexibility), or the ability to manipulate their genes, allowing them to adapt to environmental changes. This includes but is not limited to:
- Ability to adapt to increasing temperatures in their environment
- Ability to grow skeletons in an acidified environment
- Ability to generate additional energy in order to adapt to the stress caused by ocean acidification.
- Although the results provide optimism for the future of copepod populations, the next experiment demonstrates the cost of this generational adaptability to copepods’ health and reproduction.

Finding Two: Rapid evolution in order to evolve to ocean acidification decreases copepods’ ability to adapt to other environmental stressors in the future.

After twenty-three generations of copepods living in an acidified environment, scientists reintroduced some of the copepods in the less acidic environment – the current acidity level of the ocean today. The new generations of copepods that were reintroduced to this less acidic environment did re-adapt to these new conditions – but with lowered ability to respond to other kinds of stressors like a limited food supply.
The researchers explained that, in an effort to adapt quickly to acidified conditions, the copepods lost genetic flexibility (known as “phenotypic plasticity”), their ability to genetically adapt to different environmental conditions.
The copepods genetically adapted to high acidity conditions, which left them all with similar genetic makeup. This left them less able to adapt to new stressors, such as a lowered food supply. Copepods in the lower-acidity environment their ancestors had come from had smaller populations and were generally less healthy.

The scientists concluded that, while there is hope for copepods and other ocean animals to adapt to increased ocean acidity and warming ocean, there may be hidden costs for those species as a result of rapid evolution.

scientist with copepods - ocean animals adapt acidification — Professor Dr. Melissa Pespeni of the University of Vermont during the copepod experiment.
(Source: © Joshua Brown/Geomar)

Sources:

Brennan et al. “Loss of transcriptional plasticity but sustained adaptive capacity after adaptation to global change conditions in a marine copepod.” Nature, March 3, 2022, DOI: 10.1038/s41467-022-28742-6.

“Ocean life may adapt to climate change, but with hidden costs.” Science Daily, March 22, 2022. https://www.sciencedaily.com/releases/2022/03/220322150905.htm.

Researchers Discover How Ocean Acidification Unexpectedly Threatens Diatom Plankton Populations

Posted on September 7, 2022September 7, 2022 by Team Writer

Rising ocean acidity is threatening the population of the most common type of plankton, known as diatoms, one of the main oxygen producers on the planet and the primary food source for all marine life. Despite previous beliefs that diatoms actually benefit from ocean acidification, new research from the Helmholtz Centre for Ocean Research (GEOMAR) shows that diatom populations are extremely vulnerable to the effects of ocean acidification. Continue reading for a summary of the paper’s findings.

Background Information: How Ocean Acidification Affects Diatoms

Full Study: Decline of diatoms due to ocean acidification (Nature, May 2022).

how does ocean acidification affect diatoms research — Researchers studying the effects of ocean acidification on diatom populations
Source: Ulf Riebesell/GEOMAR/European Geosciences Union

How Ocean Acidification Reduces Diatom Populations

In past years, scientists believed that diatoms are less affected than other marine organisms by the effects of ocean acidification. This was because diatoms rely on silica minerals to build their shells, rather than calcium carbonate, a substance that many other marine organisms rely on to build their shells and that is reduced by ocean acidification. In fact, some scientists previously argued that ocean acidification aids diatoms by increasing their ability to photosynthesize, and thus increasing diatom populations’ growth.

But, in a recent analysis, scientists explain how ocean acidification may reduce the population of diatoms at an alarming rate. Here’s what you need to know about it.

The study researched the effects of ocean acidification on the dissolution of the silicon shell of diatoms. The results show that acidified seawater significantly slowed the ability of diatoms to dissolve their silicon shells, ultimately leading to a lowered ability to gain nutrients through photosynthesis.

The most common negative impact of ocean acidification on shell-forming marine species using calcium carbonates, such as oysters, clams, mussels, and corals, is a reduction in their capacity to form shells due to a lack of carbonate ions in more acidified seawater. While this chemical imbalance was not believed to affect diatoms due to their silicon-based shells, ocean acidification actually threatens diatoms in another way.
GEOMAR Helmholtz Centre for Ocean Research Kiel researchers used data from huge test tubes known as Mesocosms. These tubes were placed in different ocean biomes all around the world. Mesocosms can contain a large volume of ocean water inside, allowing researchers to manipulate the water parameters, such as increasing or decreasing the acidity level without harming the ocean ecosystem outside.
Using an Earth system model, the researchers utilized the collected data to simulate the negative effects of ocean acidification on diatoms in the future, on a worldwide scale.
Researchers discovered that acidified seawater slows the ability of diatoms to dissolve their silicon shells, which forces them to sink into the deeper parts of the ocean. Because of this, the abundance of diatoms on the ocean surface is lowered.
Researchers concluded that since diatoms needed to be at the surface water to get light to renew their shells, forcing them to sink may significantly decrease their population around the world at an alarming rate.

mesocosm - ocean acidification diatoms study — A photo of Mesocosm underwater
(Source: © Ulf Riebesell GEOMAR/University of Tasmania, IMAS)

diatom life cycle - ocean acidification — A comparison of the diatom life cycle today (a) and in the future, the year 2200 (b), as simulated in the study.
(Source: © Nature)

How Ocean Acidification Affects the Development of Several Marine Species

Posted on May 12, 2022June 9, 2022 by Team Writer

Rising ocean acidity is affecting the development of different types of marine species, such as sea urchins and brightly-colored reef fish.

A recent study shows how sea urchin development is affected by ocean acidification. (more…)

The Great Barrier Reef is experiencing massive coral bleaching events due to ocean acidification, which negatively affects the development of brightly-colored fish in the reef. (more…)

Background Information: What is Ocean Acidification?

Full Research: Direct and latent effects of ocean acidification on the transition of a sea urchin from planktonic larva to benthic juvenile, Are fish communities on coral reefs becoming less colorful?

Study Shows How Ocean Acidification Affects Sea Urchin Early Stage Development

Ocean acidification has a significant negative impact on marine species and ecosystems. A recent study shows how ocean acidification affects the early development stages of some marine species, such as sea urchins. Here’s what you need to know about it.

The study researched the effects of pH on sea urchin’s development and transition from fertilization to juveniles. The result shows that low pH levels significantly affected the growth and mortality of the urchin’s larval stage. Even small changes in ocean pH (on the scale of .1) can have major impacts.

Larval Stage: Effects of Ocean Acidification

Sea urchin larvae were exposed to a 7.2 pH level (compared to the current ocean’s actual pH of 8.1). The sea urchins exposed to this pH exhibited the following characteristics:
- Higher mortality rates.
- Higher abnormality rates.
- Lower growth rates.

The metabolism of sea urchin larvae exposed to a 7.2 pH level increased as well. The researchers believe that because of this, the urchins may be using additional energy to boost metabolic function, which might limit their growth rates. In other words, the sea urchins adapt to ocean acidification by shifting their energy to boost metabolic function, rather than other important functionalities. Researchers believe that this shift in energy may be what’s causing mortality and abnormalities throughout their development stages.

Settlement Stage

Researchers discovered that prolonged exposure to a 7.7 pH level significantly delayed the settlement of sea urchin larvae, an important process during which larvae settle to the ocean floor where they will eventually begin their adult life stages.
However, when the sea urchin larvae were placed under a suitable algal substrate for the settlement stage, the researchers found that the larvae remained unaffected by 7.7 pH levels. This shows that algae may help reduce the effects of ocean acidification on sea urchin larvae.

Metamorphosis Stage

The study shows that in the metamorphosis stage, all the sea urchins that were grown at a 7.2 pH level failed to metamorphose. The researchers concluded that sea urchins that are exposed to low pH levels throughout their early development stages may find it hard to impossible to achieve metamorphosis.

However, the study also shows that 30% of the sea urchin larvae that were grown at a 7.6 pH level achieved the metamorphosis stage. This shows the large impact of even a pH change of .4, compared to the 7.2 pH group of urchins.

sea urchin development - ocean acidification sea urchins — The development cycle of a sea urchin.
(Source: © Natural History Museum, London)

Ocean Acidification Affects Brightly-Colored Fish Development Through Continuous Coral Bleaching

The Great Barrier Reef is experiencing massive coral bleaching events due to ocean acidification, which negatively affects the development of fish’s color in the reef. Here’s all you need to know about the study.

In the span of just three decades, the effects of ocean acidification and global warming have caused the Great Barrier Reef to lose thousands of its coral species. This phenomenon is commonly known as massive coral bleaching events. As a result of this, the number of brightly-colored fish in the Great Barrier Reef is decreasing.

According to the study, the number of different types of brightly-colored fish in the Great Barrier Reef has declined significantly since the massive coral bleaching event of 1998. Scientists believe that the composition of the seafloor (texture, colors, patterns) affects the development of the coloration of fish.

Reef fishes developed coloration to protect themselves from predators by adapting to the different coral structures and compositions. Fish would find it useless to produce vibrant colorations in the absence of coral compositions.

The study concluded that the loss of vibrant composition and structure of the seafloor due to the massive coral bleaching events has a significant relationship to the inability of many fish to develop their vibrant colors.

coral bleaching in great barrier reef — 6^th massive coral bleaching event in the Great Barrier Reef (2022).
(Source: © Earth.org)

Sources:

“Direct and latent effects of ocean acidification on the transition of a sea urchin from planktonic larva to benthic juvenile” Nature, April 01, 2022

https://www.nature.com/articles/s41598-022-09537-7

“Fish on Australia’s Great Barrier Reef are losing their colour as corals die” Independent UK, March 23, 2022

https://www.independent.co.uk/climate-change/news/great-barrier-reef-australia-fish-colour-b2041887.html

How Are Whales Affected by Ocean Acidification?

Posted on May 10, 2022May 25, 2022 by Team Writer

Ocean acidification occurs when the pH level of seawater decreases, which is most frequently caused by the ocean absorbing excess CO₂ from the atmosphere. Ocean acidification has negative effects on a variety of ocean ecosystems and life forms, including whales.

This article will explain how whales are affected by ocean acidification and the importance of whales to ecosystems.

Background information: Ocean Acidification Infographic

Table of Contents

How Are Whales Affected by Ocean Acidification?

The Importance of Whales

Historical Whale Population Decline and Recovery

Whale Conservation Efforts

How Are Whales Affected by Ocean Acidification?

Whales are affected by ocean acidification in numerous ways.

First, whales may suffer from starvation and other diseases due to ocean acidification’s effects on their food supply. The increase of ocean acidity decreases the number of carbonate ions. This ion is essential to most shell-forming organisms including krill, which is the primary source of food for baleen whales, including blue whales and humpback whales. Without enough krill to sustain the whales, they can starve or seek alternate food sources, which may not give the appropriate nutrients the whales need, leading to malnutrition and other diseases.

There are also some studies theorizing that ocean acidification may affect the hearing abilities of whales and dolphins. This is important because hearing is crucial for whale communication. As the oceans become more acidic, the concentration of borate in the water decreases, which could affect the absorption of sound energy that whales rely on for communication. However, this theory was countered in a 2010 study, in which researchers from the Woods Hole Oceanographic Institution argued that acidification will only have a minimal effect on whales’ ability to communicate.

In summary, ocean acidification may contribute to decline in whale populations. This could become a serious problem for ocean ecosystems and climate change, as whales help to maintain balance in the ocean and atmosphere.

The Importance of Whales

Whales play a crucial role in maintaining balance in the ocean ecosystem, which helps marine life and people alike. Ocean acidification threatens the important services that whales provide. Here are some of the important roles of the world’s largest mammals.

Food Chain Guardians

In their place at the top of the food chain, whales play a very important role in maintaining the balance of the marine ecosystem and the supply of food in the ocean. For example, each day, a blue whale or a humpback whale can eat up to 40 million krill. Due to this massive appetite, overpopulation of krill is prevented, which helps preserve the ecological balance of the marine ecosystem.

Natural Nutrient Suppliers

whale deposits - whales ocean acidification — A blue whale leaving a massive amount of nutrient-rich deposits
Source: Ian Weisse / abc news Australia

Whales also act as fertilizer transporters in the ocean. Whales contribute to ocean fertilization through their deposits and urine. According to research, a sample of whale fecal matter contains 10 million times more iron than the amount of iron present in a sample of ocean water of the same weight. These nutrients are essential to the health and reproduction of different marine organisms, including phytoplankton (which help reduce ocean acidification). Because whales are migratory animals, they supply these nutrients to different ocean locations.

Climate Change Fighters

Phytoplankton usually thrive where whales are found. This is because whale deposits fertilize phytoplankton, which allows plankton to reproduce and thrive. Each year, phytoplankton absorb around 10-20 billion tons of CO₂ from the atmosphere, and are considered the world’s largest producer of oxygen, as they help account for 70% of the world’s oxygen supply. Without the nutrients whales provide, phytoplankton might not flourish, which could greatly affect the ocean’s carbon cycle and increase ocean acidification.

Historical Whale Population Decline and Recovery

The population of whales started to decline in the 11^th century as a result of the growing whaling industry. People hunted whales for oil and other products, including meat, baleen, and ambergris. This activity continued for centuries, causing the populations of different whale species to drop drastically, driving them to extinction.

whaling industry - whales ocean acidification — *Soviet whalers during the 20^th century.*
*Source:* *Hakai Magazine/* *Popperfoto/Getty Images*

In 1986, the International Whaling Commission (IWC) banned commercial whaling. Because of this, whales are finally able to recover and repopulate. Today, most of the whale species that experienced the decline are now showing some population recoveries. Here is the recent population status of some well-known whale species:

Humpback Whales

Today, the humpback whale population reaches about 80,000 as a result of global conservation efforts and policies.

Fin Whales

Fin whales were one of the most hunted whales during the whaling era of the 20^th century, but today, their population is considered healthy, reaching about 75,000.

Blue Whales

Today, blue whale populations are still pushing for recovery. Even though their population is increasing, they are still listed as endangered. The current population of blue whales is between 10,000 – 25,000.

Though ocean acidification is not listed as one of the main sources of whale mortality today, several man-made factors are still causing death to different kinds of whales. This includes:

Ship strikes
Plastic pollution
Fishing nets entanglement (bycatch)
Climate change

Whale Conservation Efforts

Globally, different organizations and government agencies are working to conserve and increase the population of whales. Since ocean ecosystem health is declining due to pollution, ocean acidification, and overfishing, whales and their sources of food are at risk. It is important that we work to conserve them, because they provide us with important services, including (indirectly) the air we breathe.

Here’s an overview of some whale conservation organizations:

World Wildlife Organization

For 50 years, the WWF has been running programs to protect whales. The organization participated in the petition banning commercial whaling in 1984.
The organization’s goal is to protect whales and dolphins using three methods:
- Improving whale monitoring and mitigating bycatch (accidental entanglement in fishing traps)

Preventing ship strikes and reducing underwater noise pollution
Protecting whale habitats

Ocean Alliance

Ocean Alliance focuses on increasing public awareness of the importance of whales.
Through the production of 40 documentaries, the organization serves as the bridge between whales and the global community, allowing people to better understand whales and their purpose.

Whale and Dolphin Conservation

Whale and Dolphin Conservation has been working on whale conservation efforts for 30 years. The organization has been successful in its mission in various ways:
- Stopping commercial whaling
- Preventing and fighting against whale captivity
- Preventing and reducing entanglements (bycatch)
- Promoting sanctuaries and protected areas for whales and dolphins

How Are Sea Urchins Affected by Ocean Acidification?

Posted on May 10, 2022May 25, 2022 by Team Writer

Ocean acidification occurs when the pH level of seawater decreases, which is most frequently caused by the ocean absorbing excess CO₂ from the atmosphere. Ocean acidification has negative effects on a variety of ocean ecosystems and life forms, including sea urchins.

This article will explore how sea urchins are affected by ocean acidification, as well as the importance of sea urchins to ecosystems, global cultures, and the economy.

Background information: Ocean Acidification Infographic

Table of Contents

How Are Sea Urchins Affected by Ocean Acidification?

The Importance of Sea Urchins

The Importance of Sea Urchins to the Ecosystem

The Importance of Sea Urchins to People and the Economy

How Are Sea Urchins Affected by Ocean Acidification?

Sea urchins are vulnerable to ocean acidification because rising acidity in seawater reduces the number of available carbonate ions, which are essential for building sea urchins’ shells, spines, and teeth. Here are some of the negative effects of ocean acidification on sea urchins.

Lowered Growth Rate of Sea Urchin Larvae

Because larval sea urchins are quite sensitive, ocean acidification affects the development of sea urchins at very early stages. According to a 2022 study, sea urchin larvae’s growth rate is lowered when they’re exposed to acidified water. Sea urchins, when exposed to lower pH seawater, need to use extra energy for other survival functions, including temperature self-regulation, leaving insufficient energy for them to use for their growth.

Increased Metabolism

Sea urchins feed on various types of marine organisms, including algae, planktons, and even kelp. Feeding is crucial to the growth, development, and survival of sea urchins. However, 2013 research discovered that increasing ocean acidity affects the metabolism of sea urchin larvae, forcing them to eat more than normal. A lower pH level reduces the capability of sea urchin larvae’s digestive enzymes, known as “gastric juice.” In order to attempt to make up for less effective digestion, sea urchin larvae exposed to acidification increased their feeding by as much as 33%. If this increased eating was not possible due to a lack of food, the sea urchin would suffer. Additionally, this increased energy devoted to eating reduces energy reserves for other vital functions such as growth and temperature self-regulation.

Increased Developmental Abnormalities and Mortality Rates

Ocean acidification forces sea urchins to reallocate their energy sources in order to adapt. This might sound positive, but experts have found that it is one of the causes of mortalities and abnormalities in sea urchins. In a 2022 experiment, sea urchin larvae were exposed to acidified water with a 7.2 pH level (much lower than the ocean’s current pH of 8.1). This showed a significant effect, causing abnormalities to the sea urchin’s structural development.

In the same experiment, when larval sea urchins were exposed to acidified water with a pH of 7.2, they were unable to grow into juvenile sea urchins. These abnormalities may threaten their survival rate.

sea urchin study - sea urchin ocean acidification — *Comparison of two sea urchins, where the sea urchin on the right is exposed to ocean current conditions, and the sea urchin on the left is exposed to ocean acidification.*
*Source:* *Phys.org*

The Importance of Sea Urchins

Sea urchins contribute to the ecological balance in the ocean ecosystem and provide products that are used in traditional cuisines. However, ocean acidification threatens sea urchin populations, and thus, the benefits they offer to ecosystems and people. Here are some of the ways sea urchins are important to ecosystems and people.

The Importance of Sea Urchins to the Ecosystem

Reef Gardeners

Sea urchins are herbivores and they feed on algae and other marine plants in the reef. Their feeding activities are essential to the balance of the reef because as they remove overgrown weeds and algae, they create room for corals to flourish. This provides more habitat for fish while also preventing the negative effects of overgrowing algae on the reef.

This service that sea urchins provide plays an essential role in maintaining a healthy and habitable marine ecosystem. They are great alternatives to the decreasing population of other algae controllers that are commonly overexploited by people, such as parrotfish and rabbitfish. If ocean acidification continues, the service of sea urchins to reef maintenance could be affected. Without sea urchins and other algae controllers, the reefs as we know them might become uninhabitable for many organisms in the future.

Source of Food for Other Species

sea otter eating urchins - sea urchin ocean acidification — *Sea otter eating sea urchins*
*Source:* *Katherine johns / listal*

Sea urchins are a food source for several other species. Sea urchins’ high protein provides essential nutrients to animals that rely on this diet. Animal species that feed on sea urchins include:

Other shellfish, such as crabs and lobsters
Multiple fish species, such as sheephead wrasse and wolf eel
Sea otters
Seagulls

Some of these animals use sea urchins as their primary source of food, which is why the negative impact of ocean acidification doesn’t only affect sea urchins directly; it can also cause an indirect effect on species that rely on their services.

The Importance of Sea Urchins to People and the Economy

How Sea Urchins Benefit the Cultural Food Industry and Economy

Like any other commercialized shellfish on the market, sea urchins are also in demand in some countries’ food industry. Here is an overview of some of the countries that use sea urchins as part of their food industry.

Chile

Chile has a long tradition of eating sea urchins, as sea urchins have been part of Chilean food since the 1500s. Today, sea urchin is still a part of the Chilean diet. In 2002, Chile consumed around 3,000 tons of sea urchins, and in 2013, Chile ranked as the world’s largest supplier of fresh and frozen sea urchins and urchin roe. Sea urchins are not only a part of Chilean tradition and culture, but they also make a significant contribution to Chile’s economy today.

Japan

sea urchin sushi - sea urchin ocean acidification — *Sea urchin sushi*
*Source:* *Sushi Making Kit*

Eating sea urchins in Japan is traditional, with consumption accounting for around 90% of the global supply. Japan is the largest consumer of sea urchins in the world, where it is commonly eaten as sushi and sashimi, two of Japan’s most iconic dishes. The sea urchin also contributes significantly to Japan’s economy since the country is considered a major exporter of sea urchins globally.

The population of sea urchins may decline as a result of the effects of ocean acidification. This could have a damaging effect not only on the economic contribution of sea urchins, but also on culinary cultures that have been passed down for centuries.

Health Benefits from Sea Urchin in the Diet

Despite their threatening appearance, sea urchins can provide various health benefits and nutrients to people. Here are some examples:

Sea urchins are high in protein, which can help maintain and grow our muscles.
Sea urchins are also rich in dietary fibers that are good for digestion.
Sea urchins contain vitamin C and Zinc, which are great for the immune system.
They also contain vitamin A, which is good for our organs, such as the heart, kidneys, and lungs.
Just like other fish, sea urchins are rich in omega 3 fatty acids, which are useful for maintaining a healthy heart.

Sea urchins provide a variety of valuable benefits to the environment, wildlife, and humans. Several studies have already proven how the acidifying ocean affects their development, preventing them from thriving. This could alter the important services they provide that help in maintaining ecological balance. This is why it is essential to assure that sea urchins, like all other species, are protected from the damaging consequences of ocean acidification.

How Are Salmon Affected by Ocean Acidification?

Posted on May 10, 2022May 25, 2022 by Team Writer

Ocean acidification occurs when the pH level of seawater decreases, which is most frequently caused by the ocean absorbing excess CO₂ from the atmosphere. Ocean acidification has negative effects on a variety of ocean ecosystems and life forms, including salmon.

This article will explain how salmon are affected by ocean acidification, as well as the importance of salmon to ecosystems, people, and the economy

Background information: Ocean Acidification Infographic

Table of Contents

How Are Salmon Affected by Ocean Acidification?

The Importance of Salmon

Ecosystems and Wildlife

People and the Economy

How Are Salmon Affected by Ocean Acidification?

salmon ocean acidification — _{Source: Timothy Knepp}

Salmon and other fish species feel the impact of ocean acidification. As acidity levels rise in the ocean, chemical imbalances are created within their bodies, which are normally balanced with the pH of the surrounding water. This can affect salmon’s behavior and abilities. Here are some of the ways ocean acidification negatively affects salmon.

Ocean Acidification Affects Salmon’s Ability to Sense Danger

Salmon are known for their extreme sense of smell, which is essential for them to search for food and avoid predators. However, when ocean acidification rises, salmon’s ability to smell is altered. According to a 2018 study, salmon that have been exposed to acidified seawater stop showing a response to the scent that tells them there’s danger nearby.

In the study, researchers created three separate salmon tanks, each with a different level of seawater acidity. After two weeks of exposure to the water, salmon in the tank with the lowest acidity levels exhibited normal reactions when the “danger scent” was put into the water. In fact, most of the time, the low-acidity salmon entirely avoided the section of the tank where the scent was coming from. On the other hand, salmon in the tank with the highest acidity levels did not respond to the “danger scent” at all, and made no attempts to avoid it.

The study reveals that ocean acidification can negatively affect salmon’s ability to sense danger. This may result in an increased mortality rate and population decrease in salmon exposed to ocean acidification.

Watch how acidic water affects salmon’s sense of smell in this demonstration from the University of Washington:

Ocean Acidification Affects Salmon’s Ability to Navigate Home

Salmon are anadromous, which means that as they mature, they migrate from the ocean to their natural spawning grounds in rivers to lay eggs. They use their extreme sense of smell to navigate the seas and rivers. This phenomenon is essential for salmon to reproduce and thrive. Unfortunately, the effects of ocean acidification on their sense of smell alter their ability to navigate home. This could prevent them from reproducing and spawning, which could also contribute to declines in their population.

Ocean Acidification Reduces Salmon’s Food Sources

In the wild, salmon mainly feed on crabs, krill, and shrimps. the negative effects of ocean acidification may impact the populations of shell-forming organisms, including many species that salmon commonly rely on for food. This could lessen the availability of salmon’s food sources, which could lead to starvation, or changing their diet. This might result in a decline in the essential nutrients salmon get from their original diet to sustain their characteristic pink features and health. In the long run, this may raise their mortality rate, reducing their population.

The Importance of Salmon

Salmon play an important role in maintaining healthy ocean and river ecosystems. They also provide benefits for marine wildlife, terrestrial wildlife, and people. However, the increasing threat of ocean acidification puts the important services that salmon provide at risk. Here are some of the ways salmon are important to ecosystems, wildlife, and people.

The Importance of Salmon to Ecosystems and Wildlife

Natural Nutrient Transporter

Since salmon are anadromous, they contribute to the transportation of nutrients from the ocean to rivers and streams. For example, in Alaska, approximately 170 tons of phosphorus are transported from the oceans to Lake Illiamna annually due to the migration of sockeye salmon. Aside from phosphorus, salmon also provide nitrogen to rivers, streams, and lakes. After they lay eggs, salmon die and release nitrogen into the waters. Phosphorus and nitrogen are essential to the growth of microorganisms and vegetation, and provide necessary nutrients to wildlife that inhabit the lake.

Food Source for Wildlife

Salmon serves as food for various types of marine and terrestrial animals. Here are some of the species that rely on salmon as their source of food:

Brown bears rely on a salmon diet for the rich calories it provides. Salmon are essential for bears, as bears need to consume around 5,000 to 20,000 calories per day, depending on the season.
Sharks, seals, and orcas consume salmon in the ocean. Salmon provides nutrients that are essential for their growth.
Bald eagles and other predatory birds that live on riversides feed on salmon when the fish return to their spawning grounds in shallow rivers and streams.

*Alaskan brown bear catching salmon in Brooks Falls*
*Source:* *Gary Lackie/Flickr*

The consequences of ocean acidification may have an impact on the availability of salmon in areas where animals and plants rely on them for nutrients and food. If the ocean continues to acidify, it will not only harm salmon, but will also have a detrimental domino effect on the ecosystem and other species that rely on the fish.

The Importance of Salmon to People and the Economy

How Salmon Benefit the Aquaculture Industry

Industrialized salmon farming started in the 1980s in Norway and quickly grew into a global industry. Today, salmon aquaculture is one of the fastest growing methods of food production today, and makes up about 70% of the global market. Salmon have a huge impact on the global economy, so the effects of ocean acidification on salmon could be quite disruptive.

How Salmon Benefit People’s Livelihoods

In 2018, almost 60 million people relied on the aquaculture industry for their source of income. Because salmon is the most-produced fish in the global aquaculture industry, it provides millions of people with employment and income.

Health Benefits of Eating Salmon

salmon on plate - salmon ocean acidification

In the 1980s, salmon was considered a fancy dish in some countries, but as the industry grew salmon became more widely available, and the health benefits and nutrients it provides to humans spread to practically every corner of the globe. Here are some examples of the health benefits of salmon:

Salmon is a good source of protein, which is essential to building muscle mass and growth.
Salmon is rich in vitamin b12 and iron, which are essential to the formation of red blood cells. This can prevent blood-related conditions like anemia.
Salmon contains potassium, which is essential in maintaining healthy muscle condition and nerve function.
Salmon also contains vitamin D, which boosts immune systems.
Salmon contains high omega 3 fatty acids. This is great for maintaining a healthy heart and reducing the chance of getting several diseases such as heart attacks, cancer, dementia, and Alzheimer’s.

The issues salmon face from ocean acidification are exacerbated by the negative pressures humans have placed on salmon populations. This includes urbanization, pollution, and dam constructions. If worsening ocean acidification is added to these pressures, salmon may not be able to continue to adapt to declining environmental conditions, and their populations will suffer.

Salmon provide a variety of services and health benefits to people, the economy, wildlife, and ecosystems, but they are threatened by ocean acidification. Ocean acidification jeopardizes the benefits we get from salmon and it may also create an ecological imbalance that could lead to other species’ extinction.

How Are Diatoms Affected by Ocean Acidification?

Posted on May 10, 2022September 7, 2022 by Team Writer

Ocean acidification occurs when the pH level of seawater decreases, which is most frequently caused by the ocean absorbing excess CO₂ from the atmosphere. Ocean acidification has negative effects on a variety of ocean ecosystems and life forms, including diatoms, a type of phytoplankton characterized by glass-like cell walls made of silica.

This article will explain how diatoms are affected by ocean acidification, and will discuss the importance of diatoms to ecosystems and people.

Background information: Ocean Acidification Infographic

Table of Contents

What Are Diatoms?

How Are Diatoms Affected by Ocean Acidification?

The Importance of Diatoms

The Importance of Diatoms to the Ecosystem

The Importance of Diatoms to People

What Are Diatoms?

Diatoms are one of the two common types of phytoplankton. They are found in bodies of water such as the ocean, rivers, lakes, and ponds, as well as in mud and moist soils. Diatoms are commonly recognized by their transparent glass-like cell walls made out of silica acids (a type of mineral) that are dissolved in water. Just like corals and other marine plants, diatoms photosynthesize in order to survive, which is why sunlight and carbon are essential to their survival. Diatoms also play a vital role in transferring atmospheric carbon to the deep ocean, which helps to prevent global warming and reduce ocean acidification.

To give you a better grasp, here is a short video explanation and microscopic footage of diatoms by MicroBiome:

How Are Diatoms Affected by Ocean Acidification?

Despite their small size, diatoms play an important role in ocean ecosystems and studies are revealing the risk ocean acidification poses to their wellbeing. Diatoms rely primarily on CO₂for their photosynthesis, so the ocean’s increased absorption of CO₂that causes ocean acidification has a large impact on the creatures. Here are some of the effects of ocean acidification on diatoms.

Ocean Acidification Could Increase the Growth of Diatoms

According to a 2019 study, high CO₂levels due to ocean acidification could increase the metabolism and growth of diatoms. This is because diatoms rely on CO₂as their source of energy in photosynthesis. However, the study’s results are still being debated and there is no final agreement on how these factors would affect the diatom community, nor how diatoms will continue to adapt to the acidifying ocean.

Ocean Acidification Slows the Development of Silica Cell Walls

ocean acidity ph scale - diatoms ocean acidification

Diatoms build their silica cell walls to protect themselves against predators such as krill. The cell wall is an important factor for their survival. According to a 2019 study published in Nature, exposure of diatoms to ocean acidification could slow their development of silica cell walls. The study reveals that even when the ocean pH level drops to 7.84 (compared to today’s pH of 8.1), the development of diatom’s silica cell walls reduces. Not only can this affect the ability of diatoms to survive, but it can create an imbalance in the ocean’s silica levels. Even small shifts in ocean acidity can have major impacts.

Ocean acidification may also impact the ability of diatoms to dissolve their shells, leading them to sink into the deep ocean. This reduces their population by making it difficult for them to get light from the surface, reducing their ability to photosynthesize to survive.

Ocean Acidification Could Alter the Efficiency of Diatoms’ Transport OF CO₂to the Deep Ocean

Diatoms play a big role in carbon sequestration. When they die, diatoms sink to the deep ocean with the help of their silica cell walls that serve as a weight and stabilizer. This process works to transport all the CO₂ the diatoms have absorbed to the ocean’s depths, thus sequestering it in the deep ocean and removing it from the atmosphere. However, the same 2019 Nature study discussed above implies that due to the slow development of silica cell walls induced by exposure to ocean acidification, the ability of diatoms to transport CO₂to the ocean’s depths might be negatively affected. Without the carbon sequestration services of diatoms, global warming could accelerate and may cause larger ecological problems, including worsening ocean acidification.

The Importance of Diatoms

Despite their microscopic size, diatoms play a massive global role in making marine and terrestrial ecosystems habitable for both people and wildlife. However, the threat of ocean acidification may put diatoms under new stressors that might affect the services they provide. Here are some of the ways diatoms are important to ecosystems and people.

The Importance of Diatoms to the Ecosystem

Primary Food Provider

Diatoms are at the bottom of the food chain. They serve as food to larger organisms like zooplankton, krill, algae eater fishes, snails, and more. These larger organisms flourish because of the abundance of diatoms. Even larger marine animals depend on the organisms that rely on diatoms. For example, the whale’s primary diet is krill. Without diatoms, krill would not be able to survive. If there are not enough krill to sustain the whales, it could cause starvation and ultimately decline in whale populations.

This hypothetical breakdown of the food chain shows the importance of diatoms as the primary food source in the food chain. Any damages to diatoms caused by catastrophic events such as ocean acidification would have a significant impact on all species who rely on their services, from the smallest krill to the largest mammal on the planet.

Natural Carbon Sink

Diatoms are considered a natural carbon sink, as they absorb up to 20 billion tons of atmospheric carbon annually. Diatoms convert atmospheric carbon into organic carbon as they absorb it through photosynthesis. When they die, they carry the stored carbon down as they sink to the ocean floor. This carbon-absorbing ability has a significant impact on mitigating global warming and climate change.

diatoms carbon cycle - diatoms ocean acidification — *Diatoms carbon cycle*
*Source:* *Frontiers in Plant Science*

The Importance of Diatoms to People

Major Oxygen Supplier

Since diatoms photosynthesize, they contribute significantly to the world’s supply of oxygen. In fact, according to the most recent data, diatoms are responsible for 25% of the global oxygen supply. Without diatoms, all species that rely on oxygen, including humans, may suffer from negative health complications due to lower oxygen supply.

Supplier of Bio-Products

Diatoms not only supply oxygen but they can also be utilized in creating bio-products, products made from natural, renewable materials. According to a recent study, diatoms can produce sustainably manufactured bio-products that could be used as pharmaceuticals that benefit people. This includes the following products:

Lipids
Omega-3 fatty acids
Pigments
Antioxidants
Exopolysaccharides
Sulfated polysaccharides

diatoms microscopic image - diatoms ocean acidification — *Microscopic view of diatoms*
*Source:* *Diatoms.org*

Diatoms can help humans in a variety of ways, including those mentioned above, and there may be many more benefits that science has yet to uncover. We already know how diatoms are affected by ocean acidification, which might alter the services they provide. It is critical to guarantee that these microorganisms continue to thrive, as without them, the Earth may become uninhabitable for humans and other species.

How Are Clams Affected by Ocean Acidification?

Posted on May 10, 2022May 25, 2022 by Team Writer

Ocean acidification occurs when the pH level of seawater decreases, which is most frequently caused by the ocean absorbing excess CO₂ from the atmosphere. Ocean acidification has negative effects on a variety of ocean ecosystems and life forms, including clams.

This article will explain how clams are affected by ocean acidification, as well as the importance of clams to ecosystems, people, and the economy.

Background information: Ocean Acidification Infographic

How Are Clams Affected by Ocean Acidification?

Clams and other shell-forming marine species are particularly vulnerable to ocean acidification. As rising acidity in seawater reduces the number of carbonate ions, shell-forming organisms like clams don’t have enough carbonate to build their shells. Here are some of the negative effects of ocean acidification on clams.

Thinner Shells

Hard and healthy clam shells are made from the combination of carbonate ions and calcium ions (both naturally present in seawater). When ocean acidification increases, the amount of available carbonate ions decreases. As a result of ocean acidification, clams have fewer resources to develop or reconstruct their shells, causing them to become thinner over time. According to research, the thickness of clamshells significantly reduces after only 3 months of exposure to acidic seawater.

Smaller Clams

Based on the result of an experiment in 2010, juvenile clams that are exposed to acidic water don’t grow as large. In acidic water, clams have less carbonate to develop their shells, so they adjust to the low availability of their environment by using less carbonate, and thus not growing as large.

clam ocean acidification reduces size — *Experiment shows how ocean acidification reduces the size of clams*
*Source:* *Global Change*

Increase in Mortality Rate

The negative effects of ocean acidification on clams don’t stop at the shell’s durability and growth. According to research, clams that are exposed to ocean acidification show an increase in mortality rate after 6 months. If ocean acidification continues to rise, this will pose a serious threat to the ecological balance of marine ecosystems and the people who rely on shellfish – particularly clams, in the aquaculture industry, which covers 38% of production globally.

The Importance of Clams

Clams play an unexpectedly important role in maintaining a healthy ocean ecosystem and provide products that benefit both marine life and people. However, the increasing threat of ocean acidification puts the important services that clams provide at risk. Here are some of the ways clams are important to ecosystems and people.

The Importance of Clams to the Ecosystem

Seawater Filtration

Considered filter feeders, clams filter seawater through their respiration and feeding process. The water flows into the clam through their cilia, and all the particles that are pulled in are trapped by their gills and transferred to their mouth to feed, while the filtered seawater is released back into the ocean. This filter-feeding activity contributes to maintaining the ocean’s water quality.

Here is an example of an experiment conducted by the University of Florida/IFAS that demonstrates the efficiency of clams in water filtration:

Ocean Nitrogen Remover

Clams accumulate nitrogen by filtering water and feeding on phytoplankton, which are rich in nitrogen. When clams are removed from the ocean, nitrogen is also removed. Through shellfish culturing and farming, clams can be utilized in nutrient bioextraction, the removal of nitrogen from the seas. This can help create the right balance of nutrients in the ecosystem. Clam’s nitrogen uptake can also help bodies of water prevent excessive algae growth that often results from too much nitrogen in the water.

Natural Nutrient Cycling

Clams cycle nutrients within an ecosystem, which help other plants and animals thrive. After digestion, clams distribute nutrients through their nitrogen-rich urine and fecal deposits that fertilize various types of marine plants such as kelp. Other marine species such as krill, sea urchins, and crabs rely on these nitrogen-fertilized plants for food.

Carbon Sequestration

Clams are also considered a carbon sink because they utilize carbon to produce calcium carbonate to develop their shells. This contributes to the sequestration of dissolved atmospheric CO₂ , which can help take carbon out of the atmosphere. This in turn can help reduce climate change and ocean acidification.

If the ocean continues to acidify, we might lose a great number of clams and other shellfish populations. Without the services that clams provide, the ocean may face an ecological imbalance that would affect many marine species.

The Importance of Clams to People and the Economy

How Clams Benefit Aquaculture and the Tourism Industry

Shellfish farming, including clam farming, is very common in coastal areas. Many people that are living in these areas rely on clams as a main source of income. For example, in 2014, the clam farming sector in Washington County, Maine employed around 640 individuals. Clamming generates many economic advantages, such as clamming-related employment possibilities, the chance to expand tourism through the clam business, and tax revenue to strengthen various programs and services.

clam sanctuary and diver - clams ocean acidification — Giant clam sanctuary promoting ecotourism in the Philippines
Source: Froirivera/Wikimedia

Another example of clams’ benefits to the economy is giant clam ecotourism in Samal Island, Philippines. Today, local communities on the island, as well as resort owners, are collaborating to protect giant clam species, which increases tourism and creates new employment opportunities for seniors and women on the island. Clam tourism also generates revenue to improve community programs and services.

With higher mortality rates, smaller sizes, and poor clam quality, the clam aquaculture and tourism sector as a whole may suffer due to ocean acidification. These negative consequences of ocean acidification on clams may harm people who rely on clams for a living, as well as the local economy that majorly depends on the clam industry.

Health Benefits from Clams in the Diet

Eating clams provides more than great flavor, as clams also provide seafood eaters with various health benefits and nutrients. Here are some examples:

Clams are rich in vitamin b12, zinc, and iron, nutrients that are important in boosting the immune system.
Clams also provide collagen, which is important for our joints, skin, and bones.
Clams contain iodine, which is important to thyroid hormone production in our body.
Just like any other fish, clams are rich in omega 3 fatty acids. This fatty acid is great for maintaining a healthy heart.
Clams are a good source of choline. This nutrient is essential for liver protection against diseases such as the fatty liver. A study also suggests that choline could prevent or lower the risk of having Alzheimer’s disease.
Clams are rich in selenium, which can increase male fertility. A study found that consuming shellfish like clams improves sperm motility.

However, research has found that clams’ exposure to ocean acidification significantly increased the amount of cobalt that clams absorb. This could be toxic to people who eat clams and may put their health at risk if the cobalt is highly concentrated. This is an indication that if ocean acidification continues, it could negatively impact not only the shellfish industry, but also human health.