2017. Two-stage exams: A powerful tool for reducing the achievement gap in undergraduate oceanography and geology classes.

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A large-volume mesocosm-based nutrient perturbation experiment was conducted off the island of Hawai‘i, USA, to investigate the response of surface ocean phytoplankton communities to the addition of macronutrients, trace metals, and vitamins and to assess the feasibility of using mesocosms in the open ocean. Three free-drifting mesocosms (~60 m3) were deployed: one mesocosm served as a control (no nutrient amendments); a second (termed +P) was amended with nitrate (N), silicate (Si), phosphate (P), and a trace metal + vitamin mixture; and a third (termed -P) was amended with N, Si, and a trace metal + vitamin mixture but no P. These mesocosms were unreplicated due to logistical constraints and hence differences between treatments are qualitative. After 6 d, the largest response of the phytoplankton community was observed in the +P mesocosm, where chlorophyll a and 14C-based primary production were 2-3× greater than in the -P mesocosm and 4-6× greater than in the control. Comparison between mesocosm and ‘microcosm’ incubations (20 l) revealed differences in the magnitude and timing of production and marked differences in community structure with a reduced response of diatoms in microcosm treatments. Notably, we also observed pronounced declines in Prochlorococcus populations in all treatments, although these were greater in microcosms (up to 99%). Overall, this study confirmed the feasibility of deploying free-drifting mesocosms in the open ocean as a potentially powerful tool to investigate ecological impacts of nutrient perturbations and constitutes a valuable first step towards scaling plankton manipulation experiments.

Drawing on the importance of place has been shown to be a powerful tool in education.  This paper explores place-based teaching (PBT) in geoscience courses at the University of Hawai‘i at Mānoa’s School of Ocean and Earth Science and Technology, where faculty and student demographics sharply differ.  Despite these differences, survey results from geoscience faculty (n=59) and students (n=83) revealed a strong consensus: 78% of students and 83% of faculty reported that PBT is an important and effective practice to reach all students.  Most faculty (91%) indicated that they currently incorporate at least some PBT practices in their geoscience classes and would like to incorporate additional ones in the future.  However, many faculty expressed concern about lack of knowledge or resources, particularly regarding PBT strategies that require a high level of cultural competency.  We therefore propose a three-layered PBT framework, where faculty can start with more accessible PBT strategies (the base layer) and progress upwards as their cultural competency deepens.  Through providing geoscience resources and professional development opportunities, we can empower faculty to include more diverse and culturally meaningful practices as their experience and knowledge deepens.

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