Mg / Ca ratios in foraminiferal tests are routinely used as paleotemperature proxies. but on long timescales. they also hold the potential to reconstruct past seawater Mg / Ca. The impact of both temperature and seawater Mg / Ca on Mg incorporation in Foraminifera has been quantified by a number of studies. https://oznicoes.shop/product-category/m-sweat-bottoms/