Marine chemistry
[2] This field encompasses a wide range of topics, such as the cycling of elements like carbon, nitrogen, and phosphorus, the behavior of trace metals, and the study of gases and nutrients in marine environments.
[2] It is influenced by plate tectonics and seafloor spreading, turbidity, currents, sediments, pH levels, atmospheric constituents, metamorphic activity, and ecology.
Moreover, increasing levels of carbon dioxide in the Earth's atmosphere have led to ocean acidification, which has negative effects on marine ecosystems.
Due to the interrelatedness of the ocean, chemical oceanographers frequently work on problems relevant to physical oceanography, geology and geochemistry, biology and biochemistry, and atmospheric science.
[3] Other major topics of interest include analytical chemistry of the oceans, marine pollution, and anthropogenic climate change.
DOM is a critical component of the ocean's carbon pool and includes many molecules such as amino acids, sugars, and lipids.
[5] DOM can be recycled and put back into the food web through a process called microbial loop which is essential for nutrient cycling and supporting primary productivity.
The refractory POM fraction can settle on the ocean floor and make relevant contributions to carbon sequestration over a very long period of time[9]
Extremophiles inhabit many unique habitats in the ocean, such as hydrothermal vents, black smokers, cold seeps, hypersaline regions, and sea ice brine pockets.
Iron-oxidation can be oxic, occurring in oxygen-rich parts of the ocean, or anoxic, requiring either an electron acceptor such as nitrate or light energy.
At another extreme, some marine extremophiles inhabit sea ice brine pockets where temperature is very low and salinity is very high.
[13][14] Marine pollution occurs when substances used or spread by humans, such as industrial, agricultural and residential waste, particles, noise, excess carbon dioxide or invasive organisms enter the ocean and cause harmful effects there.
Air pollution is also a contributing factor by carrying off iron, carbonic acid, nitrogen, silicon, sulfur, pesticides or dust particles into the ocean.
Marine calcifying organisms, such as mollusks and corals, are especially vulnerable because they rely on calcium carbonate to build shells and skeletons.
[40] Early inquiries about marine chemistry usually concerned the origin of salinity in the ocean, including work by Robert Boyle.
Modern chemical oceanography began as a field with the 1872–1876 Challenger expedition, led by the British Royal Navy which made the first systematic measurements of ocean chemistry.
The chemical analysis of these samples providing the first systematic study of the composition of seawater was conducted by John Murray and George Forchhammer, leading to a better understanding of elements like chloride, sodium, and sulfate in ocean waters[44] The early 20th century saw significant advancements in marine chemistry, particularly with more accurate analytical techniques.
[45] Over the past three decades (1970s, 19802, and 1990s), a comprehensive evaluation of advancements in chemical oceanography was compiled through a National Science Foundation initiative known as Futures of Ocean Chemistry in the United States (FOCUS).
This project brought together numerous prominent chemical oceanographers, marine chemists, and geochemists to contribute to the FOCUS report.
Roger Revelle and Hans Suess pioneered using radiocarbon dating to investigate oceanic carbon reservoirs and their exchange with the atmosphere.
On an oceanographic research vessel, a CTD is used to measure electrical conductivity, temperature, and pressure,[48] and is often mounted on a rosette of Nansen bottles to collect seawater for analysis.
Advanced analytical equipment such as mass spectrometers and chromatographs are applied to detect trace elements, isotopes, and organic compounds.
