OISO-34
| Type | Oceanographic cruise |
|---|---|
| Set | This cruise is part of the set OISO - OCÉAN INDIEN SERVICE D'OBSERVATION |
| Ship | Marion Dufresne |
| Ship owner | TAAF |
| Dates | 10/01/2024 - 06/03/2024 |
| Chief scientist(s) | LO MONACO Claire , METZL Nicolas  |
LABORATOIRE D'OCÉANOGRAPHIE ET DU CLIMAT : EXPÉRIMENTATIONS ET APPROCHES NUMÉRIQUES - UMR 7159 Institut Pierre Simon Laplace Boîte 100 4 place Jussieu 75005 Paris +33 (1) 44 27 32 48 |
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| DOI | 10.17600/18002989 |
| Objective | Observing and understanding the seasonal, interannual and decadal variations of the oceanic carbon cycle is crucial to better estimate the global carbon budget and understand its evolution, investigate ocean acidification, and validate climate models (e.g. Global Carbon Project, Global Ocean Acidification Observation Network, IPCC). To this aim, the OISO program (Oce¿an Indien Service d'Observations), initiated in 1998, collects measurements of oceanic CO2 as well as hydrological and biogeochemical parameters relevant to the carbon cycle along the repeated lines of R.V. Marion Dufresne in the South-West Indian and Southern Oceans; this coverage is an important complement to the international CO2 observing system. The main objective of the OISO-34 cruise conducted between January and March 2024 was to re-occupy the transects and stations that were frequently sampled over the last 3 decades (during the GEOSECS, INDIGO, MINERVE, OISO, KEOPS, SOCLIM and SWINGS cruises). Underway surface measurements were conducted during the entire cruises using the ship pumping system. Data were also collected in the water column using a rosette-CTD that was deployed in the different biogeochemical zones (20 stations). These observations will allow to better understand the evolution of air-sea CO2 fluxes, the accumulation of anthropogenic CO2 and ocean acidification in response to anthropogenic CO2 emissions and climate change in key regions, notably in the Antarctic zone, including the phytoplankton bloom associated with the Kerguelen Plateau. The OISO-34 data data will also be very useful for the THEMISTO program (resp. C. Cotté, LOCEAN) that investigates the response of marine organisms to their changing environment. We also contributed to the ANR/MARGOCEAN project (integrated study of matter of glacial origin, its impact and its fate in the ocean around Kerguelen Island) with surface CO2 measurements, as well as sampling for total CO2, alkalinity and oxygen (14 stations). The OISO data will be available through the international data syntheses SOCAT, GLODAP and GOA-ON. In addition to the recurring OISO observations, additional analyses were conducted to better understand the functioning of the biological carbon pump and its interannual variability, in relation to the structure of phytoplankton communities (primary production and pigments by size classes, cellular abundances, and phytoplankton diversity), building on the LEFE/SOCARB project (led by F. Planchon, LEMAR) carried out in 2023 during the OISO-33 cruise. |