Building an inclusive wave in marine science: Sense of belonging and Society for Women in Marine Science symposia.

Achieving gender equity is a long-standing and ubiquitous challenge in marine science. Creating equitable experiences for all genders in marine science requires recognizing scientists' intersectional identities, and how this leads to unique lived experiences of privilege and marginalization. One approach to increase equitable experiences for women in marine science is to create affinity groups where women can learn from each other, share their experiences, and provide support and mentorship. The Society for Women in Marine Science (SWMS) is one such organization, founded to amplify the work of early career women in marine science and create community, through events such as full-day symposium events. This study investigates the experiences of symposium attendees for four events held from 2018 through 2020, as reported in pre- and post-symposium surveys. We used quantitative analysis of the open-ended survey questions to examine the demographics of attendees and their fields of study. Qualitative thematic analysis identified the most effective aspects of the symposia, areas of logistical and content improvement for future symposia, and emphasized the unique challenges women in marine science experience. The majority of symposium attendees were white graduate students. Nearly all attendees identified as women, with a small number of men and non-binary individuals. Symposia attendees enjoyed opportunities for professional development and interactions with colleagues across career stages. We present recommendations for continuing to foster a sense of belonging in marine science and STEM more broadly, both specific to SWMS and transferable actions that can be applied for other affinity groups. These suggestions include empathetic event logistics, continual democratic evaluation, identity reflexivity among group leaders, and professional development activities targeted towards the unique needs of the affinity group. The positive responses received from SWMS's adaptive integration of survey results into symposia demonstrate that incorporating these recommendations and findings will help create an inclusive wave in marine science.

Metabarcoding Reveals Temporal Patterns of Community Composition and Realized Thermal Niches of Thalassiosira Spp. (Bacillariophyceae) from the Narragansett Bay Long-Term Plankton Time Series.

Diatoms generate nearly half of marine primary production and are comprised of a diverse array of species that are often morphologically cryptic or difficult to identify using light microscopy. Here, species composition and realized thermal niches of species in the diatom genus Thalassiosira were examined at the site of the Narragansett Bay (NBay) Long-Term Plankton Time Series using a combination of light microscopy (LM), high-throughput sequencing (HTS) of the 18S rDNA V4 region and historical records. Thalassiosira species were identified over 6 years using a combination of LM and DNA sequences. Sixteen Thalassiosira taxa were identified using HTS: nine were newly identified in NBay. Several newly identified species have small cell diameters and are difficult to identify using LM. However, they appeared frequently and thus may play a significant ecological role in NBay, particularly since their realized niches suggest they are eurythermal and able to tolerate the >25 °C temperature range of NBay. Four distinct species assemblages that grouped by season were best explained by surface water temperature. When compared to historical records, we found that the cold-water species Thalassiosira nordenskioeldii has decreased in persistence over time, suggesting that increasing surface water temperature has influenced the ecology of phytoplankton in NBay.

Characteristics of global port phytoplankton and implications for current ballast water regulations.

The International Maritime Organization and U.S. Coast Guard have implemented regulations to reduce introductions of non-indigenous species via ballast water (BW). For phytoplankton, regulations limit discharges to <10 live/viable cells mL-1 (size: 10-50 µm), ignoring other size fractions. Additionally, challenge conditions of 100 (shipboard) and 1000 (land-based) cells mL-1 are required in BW management system certification testing. How these requirements correspond to natural phytoplankton populations is poorly resolved. We analyzed phytoplankton samples from 31 major ports to evaluate: a) how natural communities compare to challenge requirements and b) abundances of unregulated size fractions (i.e., <10 and ≥50 µm). None of the ports met land-based challenge conditions, and only 32% met requirements for shipboard testing. Approximately 71% of organisms ≥50 µm were centric diatoms, also unregulated by current protocols. This study demonstrates that current regulations do not consider natural phytoplankton populations, limiting control efforts for potentially harmful non-indigenous species.

Synthetic lipids as a biocide candidate for disinfection of ballast water.

The objective of this study is to propose the use of specific synthetic lipid as an active substance (biocide) in the control of harmful aquatic microorganisms, such as pathogens and non-indigenous species, transported in ships' ballast water. The biocide candidate, without metal or halogen components, was produced from a sub-product of the edible oil industry, the lecithin. Laboratory assays were conducted with phytoplankton, zooplankton, and marine bacteria to evaluate the efficiency of the biocide. The study also considers specific biocide's characteristics related to environmental risks, such as chemical composition, persistence, bioaccumulation, and toxicity. Results showed that, in the first 24 h of treatment, the biocide effectively reduced the concentration of the planktonic micro-organisms to very low levels. Additionally, a preliminary risk evaluation pointed that biocide candidate has a low residual toxicity, also a low potential for persistence and bioaccumulation in the environment.