Scientific research is advancing the understanding of ocean dynamics through new modeling approaches for neodymium (Nd) isotope distributions. The 'bottom-up hypothesis' proposes a paradigm shift, suggesting that deep-sea sediments widely across the ocean floor serve as a dominant source of dissolved neodymium. This contrasts with earlier 'top-down' models that primarily attributed neodymium input to exchange processes along shallow continental boundaries. Traditional models, relying on these conventional assumptions, have faced challenges in accurately reproducing the observed distributions of Nd isotopes in the modern ocean. Neodymium isotopes are valuable tracers for reconstructing both modern and past ocean circulation patterns, offering insights into historical climate conditions. The 'bottom-up' approach, by considering a pervasive benthic (seafloor) flux of Nd, aims to overcome the limitations of previous models. Researchers are conducting comprehensive computer modeling studies to test this hypothesis, comparing their results with extensive measurements from the international GEOTRACES program. If validated, this hypothesis could significantly transform the ability to reconstruct deep ocean circulation in past climates. This improved understanding is critical for comprehending the cycling of vital elements like carbon and other climatically important substances, as well as inferring abyssal flow speeds, offering profound implications for climate science and paleoceanography.