Description of a global marine particulate organic carbon-13 isotope data set

Abstract

Abstract. Marine particulate organic carbon stable isotope ratios (δ13CPOC) provide insights into understanding carbon cycling through the atmosphere, ocean and biosphere. They have for example been used to trace the input of anthropogenic carbon in the marine ecosystem due to the distinct isotopically light signature of anthropogenic emissions. However, δ13CPOC is also significantly altered during photosynthesis by phytoplankton, which complicates its interpretation. For such purposes, robust spatio-temporal coverage of δ13CPOC observations is essential. We collected all such available data sets and merged and homogenized them to provide the largest available marine δ13CPOC data set (https://doi.org/10.1594/PANGAEA.929931; Verwega et al., 2021). The data set consists of 4732 data points covering all major ocean basins beginning in the 1960s. We describe the compiled raw data, compare different observational methods, and provide key insights in the temporal and spatial distribution that is consistent with previously observed large-scale patterns. The main different sample collection methods (bottle, intake, net, trap) are generally consistent with each other when comparing within regions. An analysis of 1990s median δ13CPOC values in a meridional section across the best-covered Atlantic Ocean shows relatively high values (≥-22 ‰) in the low latitudes (<30∘) trending towards lower values in the Arctic Ocean (∼-24 ‰) and Southern Ocean (≤-28 ‰). The temporal trend since the 1960s shows a decrease in the median δ13CPOC by more than 3 ‰ in all basins except for the Southern Ocean, which shows a weaker trend but contains relatively poor multi-decadal coverage.

Environmental Calibration of Coral Luminescence as a Proxy for Terrigenous Dissolved Organic Carbon Concentration in Tropical Coastal Oceans

“…It is also possible that tDOC during the NE monsoon was overestimated, since it was calculated using a fixed value for the marine endmember δ 13 C DOC , even though marine autochthonous carbon can span a relatively wide range of δ 13 C values (Verwega et al., 2021). It is also not clear whether the peatland tDOC endmember δ 13 C value used by Zhou et al.…”

“…It is also possible that tDOC during the NE monsoon was overestimated, since it was calculated using a fixed value for the marine endmember δ 13 C DOC , even though marine autochthonous carbon can span a relatively wide range of δ 13 C values (Verwega et al, 2021). It is also not clear whether the peatland tDOC endmember δ 13 C value used by Zhou et al (2021)) is appropriate during the NE monsoon, because the most likely sources of tDOC during the NE monsoon would be local or regional input from the south and east coasts of the Malay Peninsula, where few peatlands are found (Figure 1).…”

Temporal dynamics in zooplankton δ13C and δ15N isoscapes for the North Atlantic Ocean: Decadal cycles, seasonality, and implications for predator ecology

“…The models we developed could easily be updated in the future by integrating other datasets, still keeping a control on the accuracy of the predictions. Building a larger data base (see for example Verwega et al, 2021) would enable us to develop further the seasonal isoscape, in terms of coverage but also of model structures (e.g., to test specific seasonal model structure). Regarding seasonality, δ 13 C and δ 15 N values might vary asynchronously and will not necessarily share the same model structure.…”

Monsoon-driven biogeochemical dynamics in an equatorial shelf sea: time-series observations in the Singapore Strait

“…This suggests that a significant part of the particulate organic matter pool was likely detrital. Whether this detrital fraction is primarily from marine production or from terrestrial input is unclear: the overall mean δ 13 C-POC (− 21.0 ± 1.5‰) is compatible with a purely marine origin (Fry and Sherr, 1989;Verwega et al, 2021), but the small decrease in δ 13 C-POC might indicate a contribution of terrestrial POC during the SW monsoon (Fig. 5).…”