ALBERT

Description: Soil profiles were collected along a transect across the Serengeti ecosystem, in Tanzania from 2-3S and 34-35.5E, 1153 to 1677 m above sea level and 0 to 1.6 m soil depth. The samples are modern soils and the temporal span of the soil depth profiles is unconstrained, likely centuries to millennia. The survey is intended to observe soil microbial lipid biomarkers that are commonly used as proxies for temperature and pH and to assess their robustness in alkaline carbonate-precipitating soil profiles, where soil carbonate proxies can also be applied. These modern calibrations can inform reconstructions of Eastern African paleoenvironments using the same proxies in geological archives. Lipid extractions and purifications were performed at USC in 2018-2019 and abundances of branched and isoprenoidal glycerol dialkyl glycerol tetraethers were obtained by high pressure liquid chromatography mass spectrometry, performed in 2020-2021 at the University of Arizona. Contextual data include total dissolved solids and pH measurements at the University of Houston in 2020-2021. For more information, please consult associated manuscript on the GDGTs within these soil profiles: Peaple et al., (2022) Identifying the drivers of GDGT distributions in alkaline soil profiles within the Serengeti ecosystem, Organic Geochemistry, in review. A publication on the bulk organics and compound specific carbon isotopic composition of plant waxes in the same soils: Zhang, et al. (2021) Carbon isotopic composition of plant waxes, bulk organics and carbonates from soils of the Serengeti grasslands, Geochimica et Cosmochimica Acta, 311, 316-331, doi:10.1016/j.gca.2021.07.005. That study includes stable hydrogen isotopic data on plant wax, available from doi:10.1594/PANGAEA.921002. A publication on multiple oxygen isotopes within carbonates in the same soil profiles can be found at: Beverly, E.J., Levin, N.E., Passey, B.H., Aron, P.G., Yarian, D.A., Page, M. and Pelletier, E.M. (2021) Triple oxygen and clumped isotopes in modern soil carbonate along an aridity gradient in the Serengeti, Tanzania. Earth and Planetary Science Letters, 567, 116952, doi:10.1016/j.epsl.2021.116952. That study includes stable carbon isotopic data on soil carbonates, available from doi:10.5281/zenodo.4919027.

Description: Under the ocean acidification (OA) conditions predicted for 2100, the larval stages of temperate sea urchins are smaller, with reduced and abnormal skeleton and changes in metabolic rate. Here, we measure the impact of near-future and long-term predictions of atmospheric pCO2 levels on the early development of the echinometrid sea urchin Evechinus chloroticus using single male:female crosses, effect sizes and a within-study meta-analysis. Using the developmental signpost of the 16-cell stage, we show a mean delay of 5.11 min at pH 7.7 and 11.85 min at pH 7.5, which may have flow-on effects to later embryo and larval stages. Echinopluteus larvae raised in OA conditions (pH 7.7, 7.5) were 5–10% smaller in body length and 10–12% smaller in arm length than controls. Metabolic rate was highly variable between single male:female crosses—increasing in some crosses, decreasing in others—with a non-significant effect size in the meta-analysis. Preliminary experiments suggest that metabolic rate changes may be impacted by loss of mitochondrial function at low pH. Single male:female crosses showed variable OA responses in all measurements, suggesting that when assessing the population-level impacts of OA on early development of sea urchins there is a need to include high levels of biological replication.