Oceanographic research cruises are expensive and logistically challenging to execute, and there are often limited opportunities for early career scientists to gain experience leading such expeditions. This project provided training in the execution and leadership of a research cruise for 18 early career scientists. The early career scientists included 9 early career faculty (Assistant Professors and Assistant Scientists), 8 post-doctoral scholars, and 1 graduate student. Project participants planned and executed a 10-day research cruise aboard the intermediate/ocean class research vessel Kilo Moana in the waters north of Oahu, Hawaii. Intellectual Merit: The project enabled early career oceanographic scientists to collect valuable data specific to chemical and biological oceanography. The overarching scientific focus of the project was to quantify processes linking the transfer of elements (e.g., carbon, nitrogen, and phosphorus) from the well-lit upper ocean to the dimly-lit interior waters. All sampling for the cruise occurred at Station ALOHA (22°45' N, 158°W), the field site for the Hawaii Ocean Time-series (HOT) program. By concentrating sampling on this well-studied ecosystem, project participants benefitted from the wealth of time-resolved data and scientific infrastructure (i.e., personnel, equipment) available at this sampling location, allowing contextual framing of this project's research focus. The resulting cruise data have already resulted in one peer-reviewed publication and two other manuscripts in the final stages of peer-review. In addition, preliminary data acquired as part of this project also contributed to the development of at least 4 proposals submitted to the National Science Foundation, with two of these proposals resulting in funded awards. While at sea, project participants worked in research teams to address key science questions related the transfer and cycling of bioelements between the upper ocean and deeper interior waters. Project teams developed research foci that involved quantification of ocean particles, including their concentration, sinking, elemental content, and size; measurements of net and gross primary production; quantification of upper ocean bioelemental inventories; and zooplankton energetics, vertical migration, and movement of material from the upper ocean to the deep sea. Broader Impacts: Chief scientist training for this project began with a series of pre-cruise workshops that included videoconferences and an in-person workshop held in Honolulu, Hawaii, immediately prior to the research cruise. These pre-cruise workshops provided the early career scientists with information specific to writing research proposals that request shiptime, including: how to select the appropriate vessel to support the research during proposal development; the process for requesting shiptime through the University-National Oceanographic Laboratory System (UNOLS); essential components of a well-designed, pre-cruise planning document; best practices for coordinating multi-disciplinary science objectives while at sea; maximizing efficient use of shiptime at sea and in port; tips for managing communications between scientists, vessel operators, captains, and crew; and tools available for leveraging contextual information (e.g., using satellite data or site-specific datasets, etc.) to optimize the shipboard science. As part of the two-day, in-person pre-cruise workshop, project participants received information on best practices and requirements for data management, maximizing and managing science outreach via the media, and responsible conduct and civility at sea. While at sea, participants engaged the public through regular blog posts to the UNOLS website (https://csw.unols.org). In addition, project participants contributed photos and videos describing at-sea research activities to the National Science Foundation's social media sites to celebrate 2019 National Ocean Month (https://threader.app/thread/1143882169615564802). Last Modified: 05/31/2022 Submitted by: Erica Goetze