Organic Carbon

Definition

Organic carbon refers to carbon compounds that are found in living organisms and their remains, including plants, animals, and microorganisms. This form of carbon is crucial in the oceanic ecosystem, as it plays a significant role in carbon cycling, supporting marine life and influencing ocean carbon dynamics and acidification.

5 Must Know Facts For Your Next Test

1. Organic carbon is a primary component of marine food webs, serving as an energy source for various marine organisms.
2. In oceans, organic carbon is produced through photosynthesis and then consumed by bacteria and other organisms, driving the biological carbon pump.
3. The accumulation of organic carbon in the deep sea can help sequester CO2 from the atmosphere for long periods, mitigating climate change effects.
4. Ocean acidification can affect the cycling of organic carbon by altering the processes of decomposition and nutrient availability in marine ecosystems.
5. Changes in organic carbon levels can impact marine biodiversity, influencing species composition and ecosystem health.

Review Questions

• How does organic carbon contribute to marine food webs and ecosystem dynamics?
  • Organic carbon serves as the foundation of marine food webs by providing essential energy sources for a variety of organisms. Phytoplankton produce organic carbon through photosynthesis, which is then consumed by zooplankton and other marine creatures. This energy transfer is vital for maintaining ecosystem dynamics as it supports higher trophic levels, influencing species diversity and abundance in ocean environments.
• Discuss the role of organic carbon in the biological carbon pump and its significance for oceanic CO2 sequestration.
  • The biological carbon pump describes how organic carbon is transported from the surface ocean to deeper waters through the sinking of organic matter. When phytoplankton produce organic carbon via photosynthesis, a portion of it sinks after these organisms die or are consumed. This process effectively sequesters CO2 from the atmosphere for extended periods, contributing to climate regulation and reducing greenhouse gas concentrations in the atmosphere.
• Evaluate the impact of ocean acidification on organic carbon cycling and its implications for marine ecosystems.
  • Ocean acidification affects organic carbon cycling by altering microbial processes involved in decomposition and nutrient cycling. As CO2 levels rise and oceans become more acidic, microbial communities may shift, potentially slowing down decomposition rates of organic matter. This change could lead to increased accumulation of organic carbon but might also disrupt nutrient availability, impacting primary production and overall marine biodiversity. Understanding these interactions is crucial for predicting future changes in ocean health.

Related terms

Photosynthesis:

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of carbon dioxide and water, producing organic carbon as a byproduct.

Carbon Cycle: The natural cycle in which carbon atoms continuously move through the atmosphere, land, oceans, and living organisms, involving processes like photosynthesis and respiration.

Dissolved Organic Matter (DOM): A complex mixture of organic molecules found in water bodies that includes organic carbon compounds, which can influence nutrient cycling and water quality.