2.3

• What is the biological carbon pump?

  It's the exchange of CO₂ at the ocean's surface—some dissolves into water and some is vented back into the air.
• What role do phytoplankton play in the biological carbon pump?

  They use chlorophyll and sunlight to sequester CO₂ through photosynthesis, creating calcium carbonate for their shells.
• What happens when phytoplankton die?

  Their carbon-rich bodies sink to the ocean floor and accumulate as sediment—part of the carbonate pump.
• What is the carbonate pump?

  A component of the biological pump where CO₂ is transferred to the ocean floor via dead organisms, removing it from the atmosphere.
• Why is the biological carbon pump considered fragile?

  It depends on stable ocean temperatures, currents, and abundant nutrients.
• What maintains the recycling of sunken particles in the ocean?

  Upwelling currents and thermohaline circulation.
• What environmental changes threaten the carbon pump system?

  Slight temperature shifts, increased population, water turbulence, and slowed currents like the Gulf Stream.
• Why is the breakdown of the biological carbon pump a concern?

  Because it's highly vulnerable to climate change, which could disrupt the ocean's role in sequestering carbon.
• How do terrestrial primary producers sequester carbon?

  Through photosynthesis, converting CO₂ into plant biomass.
• What does the amount of stored carbon depend on in terrestrial ecosystems?

  It varies based on biome type and environmental conditions.
• How is carbon returned to the atmosphere from plants and animals?

  Through respiration and decomposition.
• What do primary consumers do in the carbon cycle?

  Feed on producers and release carbon through respiration
• What organisms are biological decomposers and what is their role?

  Insects, worms, and bacteria—they break down dead material and return carbon to the atmosphere.
• What can cause rapid release of soil carbon?

  Deforestation and land use changes.
• What are mangroves and where are they found?

  Coastal forests in tropical/subtropical areas like Africa, Asia, the Americas, and Australia.
• How much carbon do mangroves sequester annually?

  About 1.5 metric tonnes per hectare per year.
• Why is carbon stored in tundra soils?

  The permafrost locks in roots, dead material, and organic carbon.
• When does microbial activity occur in the tundra?

  Only in the surface layer when it thaws.
• What happens to carbon in permafrost most of the year?

  It remains frozen and stored, preventing release into the atmosphere.
• Why don't tropical rainforests have large soil carbon stores?

  Because litter and dead wood decay and are recycled rapidly.
• How much of global net primary production comes from tropical rainforests?

  Around 30%.
• What would be the impact of losing tropical rainforests?

  A significant loss of one of the Earth's largest carbon sinks