Marine Carbon Cycle Flashcards

Vocabulary flashcards covering the properties of carbon, its reservoirs, the mechanisms of the marine carbon cycle (pumps), chemical reactions in seawater, and human impacts on the cycle.

Atomic Number of Carbon

$$6$$

Atomic Mass of Carbon

$$12.01115$$

Physical Properties of Carbon

Melting Point: $3500\,^{\circ}C$; Boiling Point: $4827\,^{\circ}C$; Density: $2.2\,gcm^{-3}$

Biogeochemical Cycle

A cycle where carbon moves through different components involving biological interactions, geological activities, and chemical reactions.

Atmosphere (Carbon Reservoir)

A dynamic reservoir containing gases such as Methane and $CO_2$, influenced by natural and anthropogenic activities.

Biosphere (Marine Ecosystem)

Includes phytoplankton that absorb $CO_2$ during photosynthesis, forming the base of the oceanic food web.

Hydrosphere (Carbon Sink)

Holds dissolved inorganic carbon as bicarbonate and carbonate; it absorbs approximately $25\%$ of anthropogenic $CO_2$ emissions.

Lithosphere

Includes fossil fuels, sedimentary rocks like limestone, and soil organic matter where carbon is stored for millions of years.

Ocean Carbon Store Amount

$38,000 - 40,000$ billions of metric tons.

Marine Sediments & Sedimentary Rocks Store Amount

$66,000,000 - 100,000,000$ billions of metric tons.

Marine Carbon Cycle

Processes by which carbon is continuously exchanged within the ocean and with the atmosphere; the ocean contains roughly $60$ times more carbon than the atmosphere.

Dissolved Inorganic Carbon (DIC)

Inorganic carbon found in simple compounds like carbon dioxide ($CO_2$), carbonates, carbonic acid ($H_2CO_3$), and bicarbonate ($HCO_3^-$).

Particulate Inorganic Carbon (PIC)

Inorganic carbon including coccolithophores, foraminifera, and coral fragments.

Dissolved Organic Carbon (DOC)

Organic molecules dissolved in seawater.

Particulate Organic Carbon (POC)

Organic carbon in particulate form, including detritus and living organisms.

Carbonic Acid Formation Reaction

$$CO_{2(gas)} + H_2O \rightleftharpoons H_2CO_{3(aq)}$$

Bicarbonate Dissociation Reaction

$$HCO_3^- \rightleftharpoons CO_3^{2-} + H^+$$

Pre-Industrial Atmospheric $CO_2$ Concentration

Roughly $280\,\text{ppm}$.

Solubility/Physical Pump

A physicochemical process where $CO_2$ is transported to ocean depths, driven by the solubility of $CO_2$ in water and the Global Ocean Conveyor Belt.

Biological Pump

A biologically mediated process involving photosynthetic uptake of atmospheric $CO_2$ by marine microorganisms for sequestering carbon in deep oceans.

Carbonate Pump

Also known as the "hard tissue pump," it involves marine organisms at the surface generating particulate inorganic carbon as calcium carbonate ($CaCO_3$).

$$C_{soft}$$

Respired $CO_2$ added to the ocean by the respiration of sinking organic particles.

$$C_{carb}$$

Dissolved $CO_3^{2-}$ added to the ocean by the dissolution of biogenic $CaCO_3$.

Coccolithophore

A vital marine phytoplankton group that produces calcium carbonate shells and contributes to the carbonate pump's downward transport of carbon.

Ocean Acidification

The decrease in ocean pH levels caused by excess anthropogenic $CO_2$, which lowers carbonate saturation and affects calcifying organisms.

C. David Keeling

Scientist from Scripps Institution of Oceanography who began the longest record of direct atmospheric $CO_2$ measurements in March 1958.

Mauna Loa Observatory

Facility in Hawaii located at $3,400\,\text{meters}$ above sea level used for atmospheric studies due to its distance from pollution.