Lucie Cassarino

• Doctor of Philosophy
• Researcher at Université de Bretagne Occidentale

The three most abundant stable isotopes of Silicon (Si), 28Si, 29Si, and 30Si, all occur in plants. Isotope studies are a potential tool to explore uptake and function of plant Si, and it is a developing field. However, there is a lack of studies from natural environments, and species from the African continent, and all plant parts including reprod...

The element silicon is everywhere! In fact, silicon is the second most abundant element in Earth’s crust. Silicon in rocks and minerals breaks down and is transported from rivers and streams into the world’s oceans. Many marine organisms need silicon as it is a crucial nutrient to build their skeletons. Silicon eventually reaches the seafloor, but...

The stable isotopic composition of diatom silica is used as a proxy for nutrient utilisation in natural waters. This approach provides essential insight into the current and historic links between biological production, carbon cycling and climate. However, estimates of isotopic fractionation during diatom silica production from both laboratory and...

The stable isotopic composition of diatom silica is used as a proxy for nutrient utilisation in natural waters. This approach provides essential insight into the current and historic links between biological production, carbon cycling and climate. However, estimates of isotopic fractionation during diatom silica production from both laboratory and...

In this study we evaluate the benthic fluxes of silicic acid along the West Antarctic Peninsula (WAP). Silicic acid (DSi) is one of the macronutrients essential in fuelling biological hot spots of diatom‐dominated primary production along the WAP. Here we measure the concentration and stable silicon isotopic composition of DSi in porewater profiles...

Many studies use sedimentary biogenic silica (bSiO2) stable isotopes (e.g., δ³⁰Si) as paleoproxies but neglect signals from other sedimentary reactive SiO2 phases. We quantified δ³⁰Si for multiple reactive Si pools in coastal river‐plume sediments, revealing up to −5‰ difference between acid‐leachable and alkaline‐digestible amorphous SiO2. Thus, p...

The marine silicon cycle is intrinsically linked with carbon cycling in the oceans via biological production of silica by a wide range of organisms. The stable silicon isotopic composition (denoted by δ30Si) of siliceous microfossils extracted from sediment cores can be used as an archive of past oceanic silicon cycling. However, the silicon isotop...

The polar region is experiencing one of the most rapid environmental changes driven by atmospheric warming, and feedbacks within the cryosphere. Under such a setting, it is crucial to understand the biogeochemical cycling of the nutrient silicon (Si) in the high latitudes, which is regulating the nutrient supply to polar ecosystems, and is linked t...

The marine silicon cycle is intrinsically linked with carbon cycling in the oceans via biological production of silica by a wide range of organisms. The stable silicon isotopic composition (denoted by δ³⁰Si) of siliceous microfossils extracted from sediment cores can be used as an archive of past oceanic silicon cycling. However, the silicon isotop...

Reconstruction of silica cycling in the oceans is key to a thorough understanding of past climates because of the inherent links between the biogeochemistry of silicifiers and sequestration of organic carbon. Diatoms are one of the most important phytoplankton groups in determining export production from surface waters, and rely largely on upwellin...

The silicon isotopic composition (δ30Si) of deep sea sponges' skeletal element – spicules – reflects the silicic acid (DSi) concentration of their surrounding water and can be used as natural archives of bottom water nutrients. In order to reconstruct the past silica cycle robustly, it is essential to better constrain the mechanisms of biosilicific...

The silicon isotope composition of deep-sea sponges skeletal element – spicules – reflects the silicic acid (DSi) concentration of their surrounding water, and can be used as natural archives of bottom water nutrients. In order to reconstruct the past silica cycle robustly, it is essential to better constrain the mechanisms of biosilicification, wh...

The silicon isotope composition (δ³⁰Si) of dissolved silicon (DSi) and biogenic silica (BSi) provides information about the silicon cycle and its role in oceanic carbon uptake in the modern ocean and in the past. However, there are still questions outstanding regarding the impact of processes such as oceanic mixing, export and dissolution on the is...