 Our article on how eutrophication and hypoxia affect the species and functional diversity of marine bivalves is now available open access in the journal Continental Shelf Research (here). Here's a thread about our study and the individuals who contributed to it. Anthropogenic nutrient pollution and hypoxia are growing challenges globally. Understanding how these combined stressors affect species and functional diversity is important for anticipating future changes in coastal ecosystems and for establishing appropriate management targets. Unfortunately, few regions have biomonitoring programs that were started before anthropogenic eutrophication. To address this limitation, scientists often use a space-for-time approach, comparing populations in areas characterized by different environmental conditions as analogues for past or future conditions. For our study we focused on the northern Gulf of Mexico, a region that includes the second largest dead zone in the world. We collected live bivalve mollusks from samples of seafloor sediment at 15 subtidal stations that span more than 600 km of continental shelf habitat. In the northern gulf, higher productivity and lower oxygen concentrations occur offshore of larger watersheds like the Mississippi River and Mobile Bay, in contrast with coastal regions influenced by much smaller watersheds (e.g., the Panhandle of Florida) which have lower productivity and normoxic conditions. We identified to species ~1500 individual bivalves in our samples and characterized them based on their functional traits (i.e., feeding, mobility, fixation, life position relative to the sediment-water interface, & individual body size). We compared species & functional diversities at a standardized sampling coverage with regional environmental conditions and found higher diversities in less eutrophic settings characterized by normoxic conditions. Diversities declined in eutrophic and hypoxic environments and shifted from abundant suspension feeders to mostly deposit/mixed-feeders. Hypoxia-tolerant, organic-loving bivalves increased in body size in these settings due to greater food, +/or reduced competition/predation. My lab group collected these samples in 2018 with support from the National Science Foundation and the National Academies' Gulf Research Program. It was the 1st field season supported by my CAREER grant and it was a dream come true to do this work alongside such curious, engaged, & positive undergraduate research students. This research would also have never been possible without the contributions of the vessel captains, crew, & technical support staff that we work with at the following marine labs in the gulf coast: LUMCON, DISL, and FSUCML. I went through the tenure process at my former institution during the academic year following that field season (2018-2019). I was anxious about whether I would be able to keep my job, and also anxious about whether receiving tenure would limit my opportunities to go elsewhere. I found great solace that year in going to the lab and collecting data on the species that we had sampled, often with a soundtrack of summer fieldwork faves blasting in the background; it engaged my thoughts in a way that I was immensely grateful for. The challenge was that I was unfamiliar w/ many of these species. I spent countless hours working out how to ID them, and to chronicle this and crowd-source my malacological challenges, I posted species pics tagged #NameThatBivalve to twitter. My colleague, Katie Collins consistently came to the rescue! Katie was doing a postdoc at the University of Chicago and we often found ourselves in our labs/offices at the same time of night. They were generous with their expertise and encouraging, and it was invaluable for me to have another set of eyes (albeit virtually) on these specimens. In fall 2019 I interviewed for the position I currently hold at Colgate and flew to Okinawa for a biodiversity workshop organized by Moriaki Yasuhara and Yasuhiro Kubota. That meeting led to a number of collaborations, including this one with Anne Chao and Marina Rillo. Anne (jokingly?) told the group in Okinawa that analyzing data was her hobby and to be in touch if we had projects to discuss. At the meeting, I also talked a lot with Marina Rillo, a postdoc working with Helmut Hillebrand, about her research on community structure and space-for-time comparisons. Fast forward through my family's move to upstate New York in 2020, through the setting up & unpacking of my lab during COVID, resuming & completing data collection for our 2018 live samples, etc. I reached out to Anne, Katie, and Marina about collaborating on this project. Anne is based at National Tsing Hua University in Taiwan, Katie is at the Natural History Museum in England, and Marina is at University of Oldenburg in Germany. Timing of zoom meetings was not always straightforward but discussing our work together was such a treat for me. Each of us brought complementary insights, including coverage-based methods for diversity analysis, molluscan functional traits & taxonomy, environmental measures and their relation to community structure, etc. People showed up, followed through, and taught each other. It was great. As we prepared our manuscript, I asked also Lena, my 17 year old kid, to contribute. Lena is a talented artist and helped us by drafting the block diagram that we used in Fig 1 which illustrates the differences between taxonomic & functional diversity; it was so much fun working on this with them. I am pleased to share our work and grateful to all of these folks for their contributions. Our manuscript is available here (https://sciencedirect.com/science/article/pii/S0278434324001699); all code & data have been submitted to dyrad & zenodo & will be available soon (https://doi.org/10.5061/dryad.4tmpg4fhk; https://doi.org/10.5281/zenodo.10080545). Comments are closed.
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