The biological carbon pump has a greater impact today on carbon cycling than scientists ever thought. It is one of the main ways in which oceans influence climate changes through their capacity to absorb carbon dioxide.
To learn about the biological carbon pump and its biological process, its impact on the ocean’s health, and more, dive on with us on this journey.
What is the Biological Carbon Pump?
The biological carbon pump refers to the process by which photosynthesis helps to fix carbon dioxide into organic matter, which is then transported into the deep ocean. In other words, it’s a series of biological processes that sequester carbon to the ocean floor, away from the Earth and its atmosphere.
You can also look at the biological pump as the most crucial part of the oceanic carbon cycle. It cycles organic matter formed during photosynthesis by phytoplankton and calcium carbonate formed into shells by mollusks, plankton, and other organisms.
How Much Carbon Does It Capture?
It transfers approximately 11 gigatonnes of carbon per year into the ocean’s interior.
Currently, the atmospheric carbon dioxide is approximately 360 ppm. If the biological pump were turned off, the pressure would rise to approximately 550 ppm. If the biological pump operated as required, it would drop to 140 ppm. This is a massive difference!
Significance
The biological carbon has great significance in the global carbon cycle. Understanding the mechanisms of the biological carbon pump equips us with the required knowledge to preserve the ocean and the environment.
Its size is impressive!
Contrary to what experts thought, the biological pump captures more carbon today than ever. According to a scientific report posted on the official website of Woods Hole Oceanographic Institution (WHOI), the size of the sunlit zone is twice as large as previously thought. Phytoplankton absorbs carbon dioxide from the surface of the ocean. So, the size of the sunlit area affects the pump’s efficiency. This means that there is more area for phytoplankton to thrive and produce oxygen, and importantly, more capacity for the ocean to absorb and process CO2 through.
It is the strongest bioactive carbon reservoir
The strength of the deep ocean carbon sink is greater than all other bioactive carbon reservoirs, regulating the Earth’s climates. All the biological, chemical, and physical processes are directly affected by the spatial and temporal parameters, and the entire oceanic ecosystem is influenced by these processes.
It plays a role in biodiversity and the food chain too
The functioning of the oceanic biological pump is not only relevant to the modulation of Earth’s climate but also constitutes the basis for marine biodiversity and
key food resources that support the human population.
Impact on Climate Change
The climate is ever-changing because of the ongoing anthropogenic changes to our planet that include global warming, acidification, and deoxygenation of the ocean waters. Because of these climatic changes, the certainty of how the biological carbon pump will respond to the changes cannot be predicted. It is key in the following processes related to climate change:
Carbon Cycle
The carbon cycle sustains life on Earth by ensuring a delicate balance in carbon levels. The Carbon cycle encompasses carbon fixation, respiration, decomposition, carbon storage in soils and forests and exchange with the oceans. The arbon cycle is responsible for carbon sequestration.
Carbon Sequestration
Carbon sequestration is the process of capturing, securing, and storing carbon dioxide from the atmosphere. The idea is to stabilize carbon in solid and dissolved forms so that it doesn’t cause the atmosphere to warm. The process shows tremendous promise for reducing the human “carbon footprint.”
There are three main types of carbon sequestration:
- Biological
- Geological
- Technological
Scientists believe that humans have upset this balance by burning fossil fuels, which has added more carbon to the atmosphere than usual and led to climate change and global warming.
Did you know?
- When carbon dioxide (CO2) is released into the atmosphere from the burning of fossil fuels, approximately 50% remains in the atmosphere, while 25% is absorbed by land plants and trees, and the other 25% is absorbed into certain areas of the ocean.
- Colder regions are capable of absorbing more CO2 than warm regions, so the polar regions tend to be sinks of CO2 (see the North Atlantic and Arctic)
- By 2100, much of the global ocean is expected to be a sink of CO2 from the atmosphere.
How Does It Work?
There are two significant processes that make up the biological carbon pump. Plenty of carbon is available in the atmosphere and on the surface of the water. The biological carbon pump brings these gases into the ocean’s ecosystem.
Let’s see more on this below to help you understand how the biological pump removes greenhouse gases like carbon dioxide from the atmosphere.
Step 1: Transferring Carbon into the Biological Carbon Pump
Organisms that live in the ocean help to remove carbon from the atmosphere into the ocean.
In the initial stages, one-celled organisms known as phytoplankton (Greek for drifting plants) drift into the sunlit zone to manufacture their food.
Like other green plants, these microscopic organisms use the green-coloring matter called chlorophyll to capture sunlight. After that, they extract carbon dioxide and use it with nutrients such as iron, vitamin B, and nitrogen to convert the gas and water into simple sugars. Phytoplankton needs these sugars (carbon compounds) to survive and reproduce.
The carbon compounds and some traces of excess carbon dioxide can remain in the body of these living things as long as they exist (alive or dead).
Step 2: Moving Carbon Around in the Biological Pump
Phytoplankton brings carbon into the planktonic food web by creating a biological pump. When fish or any other animals feed on them, the transfer of the compounds within the food web begins.
What’s more, when phytoplankton or animals that depend on it for food die, they begin to sink, taking carbon-containing particles with them down into the deep of the ocean.
Key Players In The Process
The biological carbon pump is driven by a complex network of organisms in the ocean that play crucial roles in carbon uptake, transformation, and export. Among these organisms, phytoplankton, zooplankton, and marine microbes are the primary actors in regulating the flow of carbon through marine ecosystems.
1. Phytoplankton
Phytoplankton are microscopic, photosynthetic organisms that form the base of the marine food web. They include various types of algae, cyanobacteria, and other single-celled plants. Phytoplankton play a fundamental role in the biological carbon pump by absorbing carbon dioxide (CO2) from the atmosphere during photosynthesis. Through this process, they convert CO2 and sunlight into organic carbon compounds, releasing oxygen as a byproduct.
2. Zooplankton
Zooplankton are small, drifting animals that feed on phytoplankton and other organic matter. They comprise a diverse array of organisms, including copepods, krill, and small jellyfish. Zooplankton play a critical role in the biological carbon pump by grazing on phytoplankton and transferring carbon from the surface ocean to deeper layers through two main pathways:
- Direct consumption: Zooplankton consume phytoplankton and assimilate organic carbon into their own biomass. Some of this carbon is respired back into the water column as CO2, while the rest is excreted as fecal pellets.
- Vertical migration: Some zooplankton species exhibit diel vertical migration, moving vertically within the water column to feed at the surface during the night and retreat to deeper, darker waters during the day. This behavior transports carbon-rich organic matter from surface waters to deeper layers, enhancing carbon export.
3. Marine Microbes
Marine microbes, including bacteria, archaea, and protists, are essential players in the biological carbon pump. They play diverse roles in carbon cycling, including the breakdown of organic matter, nutrient regeneration, and microbial loop processes. They play a significant role in transforming organic carbon into inorganic forms that can be exported from surface waters, thus preventing the accumulation of carbon near the ocean surface.
Factors Affecting the Biological Carbon Pump
Here are some key factors that affect the biological carbon pump:
Phytoplankton
- Phytoplankton, microscopic photosynthetic organisms, are central to the biological carbon pump. Their efficiency in sequestering carbon depends on their physiological characteristics and community composition.
- Factors such as nutrient availability, temperature, and light availability influence phytoplankton growth and productivity.
- Changes in these factors due to climate change can impact the abundance, size, and species composition of phytoplankton, affecting their ability to fix carbon.
Carbonate System
- The carbonate system in seawater affects the solubility of CO₂. As CO₂ dissolves in seawater, it forms bicarbonate ions (HCO₃⁻) and carbonate ions (CO₃²⁻).
- The availability of bicarbonate and carbonate ions influences the production of organic matter by phytoplankton.
- Changes in ocean pH due to increased CO₂ levels (ocean acidification) can alter the carbonate system and impact the biological pump.
Physical Oceanographic Conditions
- Stratification of the water column affects nutrient supply to surface waters. Warm surface waters tend to be less nutrient-rich.
- Vertical mixing and upwelling bring nutrients from deeper layers to the surface, supporting phytoplankton growth.
- Changes in ocean circulation patterns and temperature can impact nutrient availability and, consequently, the biological pump.
Zooplankton Grazing
- Zooplankton (small animals) consume phytoplankton. Their grazing regulates phytoplankton populations.
- When zooplankton excrete or die, they release organic matter (fecal pellets) that sinks to deeper ocean layers (export).
- The balance between grazing and export influences the net carbon sequestration by the biological pump.
Microbial Processes
- Microbes play a critical role in breaking down organic matter produced by phytoplankton.
- The microbial carbon pump (MCP) involves processes like heterotrophic bacterial degradation of organic carbon.
- The efficiency of microbial processes affects the fate of organic carbon—whether it remains in the water column or sinks to the deep ocean.
Protecting the Biological Carbon Pump
The biological carbon pump is a key player in Earth’s carbon cycle, essential for transferring carbon from the atmosphere and land into the ocean’s depths.
Its future and, in fact, that of our entire ocean and planet, depends on what humans do to rectify the evils they have committed against the environment. Humans need to minimize pollution and create artificial carbon sinks designed to save the ocean. As we’ve seen, the biological pump relies on biological processes to function. Unfortunately, research shows that most microorganisms thrive in non-acidic habitats. In other words, pollution can wipe away life from the ocean, marking the biological pump’s end.
To optimize its function, several strategies can be employed, including:
Preservation of Ocean Ecosystems
Ensuring the health of marine ecosystems, particularly focusing on phytoplankton and zooplankton, is crucial. These organisms play a significant role in carbon sequestration, making their well-being essential for the efficiency of the pump.
Mitigation of Ocean Pollutants
Addressing pollutants such as plastics and chemicals is imperative. By reducing these contaminants, we can mitigate their harmful effects on marine life and enhance the effectiveness of carbon capture processes.
Promotion of Sustainable Fishing
Promoting sustainable fishing methods is critical for maintaining the balance of marine ecosystems. Overfishing can disrupt food webs, impacting the biological carbon pump’s functionality.
Marine Protected Areas
Designating marine protected areas helps safeguard critical habitats that contribute to carbon sequestration. These areas play a vital role in preserving biodiversity and ensuring the long-term health of oceanic carbon sinks.
Mitigation of Climate Change Impacts
Addressing climate change is essential for maintaining the integrity of the biological carbon pump. By reducing greenhouse gas emissions, we can mitigate the adverse effects on oceanic conditions and support efficient carbon sequestration.
Research And Monitoring Initiatives
Investing in research and monitoring efforts enhances our understanding of the biological carbon pump’s dynamics. This knowledge enables us to develop informed conservation strategies and adapt to changing environmental conditions effectively.
Ocean Insights: Hear From Our Experts
By Rida Nasir
Researcher and Conservationist, with an MSc in Environmental Science
The biological carbon pump is super important for capturing carbon, but it's facing challenges due to changes in the environment. In my research, I've found strong evidence showing just how valuable the biological carbon pump is, especially considering that the ocean holds about 60 times more carbon than the atmosphere. This shows us how crucial it is to pay attention to and protect the biological carbon pump.
FAQs
How does the biological carbon pump help regulate climate?
The biological carbon pump helps regulate the climate by removing carbon dioxide from the Earth’s surface and moving it into the deep layers of the ocean. This way, it reduces the volume of greenhouse gases in the Ozone layer that cause global warming and changes in weather patterns. In other words, the inefficiency of the pump is responsible for the prevalence of unpredictable climatic conditions and weather patterns.
How does the biological pump affect the carbon cycle?
The biological pump affects the carbon cycle by bringing some carbon atoms into the ocean and releasing some of them back into the atmosphere. Once it captures and takes carbon into the deep sea, the amount of carbon on the water’s surface reduces temporarily. However, most of these gases that diffuse into the water go back into the atmosphere and allow the carbon cycle to continue.
What is the difference between the microbial carbon pump and the biological carbon pump?
The biological carbon pump involves larger organisms like phytoplankton and zooplankton transferring carbon through the ocean, with sinking organic matter sequestering carbon in the deep ocean. In contrast, the microbial carbon pump involves microorganisms decomposing organic matter, releasing carbon dioxide back into the water column, and influencing the efficiency of the biological carbon pump.
What are the three types of carbon pumps?
The three types of carbon pumps refer to the processes that move carbon from the surface ocean into the deep sea, effectively removing it from the atmosphere for extended periods. These are the biological pump, the carbonate pump, and the physical pump, also known as the solubility pump.
