Impacts Of Ocean Acidification On Marine Life By Year 2100

Summary

Marine pteropods, also known as sea butterflies, are a crucial food source for ocean ecosystems. However, ocean acidification, caused by rising CO2 levels, threatens their survival by dissolving the calcium carbonate in their shells. This acidification, which lowers ocean pH, is expected to worsen by 2100, impacting marine species that rely on shells, like pteropods, corals, and shellfish. Research has shown that shallow ocean waters are most affected, which could disrupt food webs and fisheries. These changes are already observable globally, posing risks to marine biodiversity and coastal economies.

Takeaways

• 😀 Marine pteropods, also known as sea butterflies, are essential to the ocean food chain and a significant food source for fish and other organisms.
• 😀 Ocean acidification is a result of rising CO2 levels in the atmosphere, which are absorbed by the ocean and react to form carbonic acid.
• 😀 The increasing CO2 levels in the ocean cause a decrease in pH, making seawater more acidic, which is harmful to marine life.
• 😀 Projections suggest that the ocean's average pH will drop from 8.2 to 7.8 by the end of the century if current CO2 emission levels persist.
• 😀 Even a small decrease in ocean pH can have a significant impact on marine species, especially those that rely on shells and exoskeletons, like pteropods and corals.
• 😀 Ocean acidification reduces the availability of calcium and carbonate ions, which marine species need to build their shells and skeletons.
• 😀 The shell-building minerals available in seawater have already decreased over the past few decades, with surface waters being the most impacted.
• 😀 Shallow ocean waters, where most marine productivity occurs, are more vulnerable to ocean acidification than deeper waters.
• 😀 This ocean chemistry shift could disrupt marine food webs, impacting organisms like phytoplankton, zooplankton, coral reefs, shellfish, and fish species.
• 😀 Ocean acidification not only affects marine biodiversity but also threatens the livelihoods of people who depend on marine species for food and economic activities.

Q & A

What are marine pteropods, and why are they important in the ocean?

Marine pteropods, also known as sea butterflies, are small, shell-bearing organisms found throughout the ocean. They are a major food source for fish and other marine organisms, playing a crucial role in oceanic food webs.

How does ocean acidification affect marine life, particularly pteropods?

Ocean acidification, caused by increased carbon dioxide (CO2) in the atmosphere, lowers the pH of seawater, making it more acidic. This acidification reduces the availability of calcium carbonate, the mineral needed by species like pteropods to form their shells. As a result, their shells may begin to dissolve.

What causes the increase in CO2 levels in the atmosphere?

The burning of fossil fuels such as coal, oil, and gas has caused CO2 levels in the atmosphere to rise. This increase in atmospheric CO2 is the primary driver of climate change and ocean acidification.

How does CO2 affect the chemistry of the ocean?

When CO2 is absorbed by seawater, it reacts with water to form carbonic acid. This acid dissociates, releasing hydrogen ions (H+), which lower the pH of the ocean, making it more acidic over time.

What is the projected impact of ocean acidification on ocean pH levels by the year 2100?

By 2100, if CO2 emissions continue at the current rate, the average pH of the ocean is projected to decrease from 8.2 to 7.8. This relatively small drop could have significant effects on marine life, especially species that rely on calcium carbonate for their shells and skeletons.

Why is the decrease in ocean pH potentially harmful to marine species?

The decrease in pH reduces the availability of dissolved calcium and carbonate ions, which are essential for species like corals, pteropods, and shellfish to build their shells and skeletons. Without these minerals, their shells may dissolve, threatening their survival.

How do scientists measure the effects of ocean acidification?

Scientists, including those at NOAA, have conducted research cruises and collected thousands of ocean water samples to measure changes in pH and the availability of shell-forming minerals. This data helps track how ocean chemistry is changing over time.

What changes have been observed in ocean chemistry between 1991 and 2005?

Between 1991 and 2005, the availability of shell minerals decreased significantly in surface waters, as indicated by the shift from yellow to blue colors in the data. This shows that ocean acidification is affecting shallower waters more than deeper waters.

Why are shallow waters more affected by ocean acidification than deeper waters?

Shallow waters are more affected because they are where most of the ocean's productivity occurs, including the majority of marine life. These areas are also more exposed to changes in surface chemistry, which makes them more vulnerable to acidification compared to deeper waters.

What is the potential impact of ocean acidification on global food webs?

Ocean acidification could disrupt food webs by affecting key organisms like phytoplankton, zooplankton (including pteropods), and shellfish. These species form the foundation of marine food chains and support economically important fisheries, such as salmon and shellfish, which many coastal communities depend on.