Serrato Marks
Gabriela
Serrato Marks
Gabriela
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ArticleEvidence for decreased precipitation variability in the Yucatán Peninsula during the mid-Holocene(American Geophysical Union, 2021-05-06) Serrato Marks, Gabriela ; Medina-Elizalde, Martín ; Burns, Stephen J. ; Weldeab, Syee ; Lases-Hernandez, Fernanda ; Cazares, Gabriela ; McGee, DavidThe Yucatán Peninsula (YP) has a complex hydroclimate with many proposed drivers of interannual and longer-term variability, ranging from coupled ocean–atmosphere processes to frequency of tropical cyclones. The mid-Holocene, a time of higher Northern Hemisphere summer insolation, provides an opportunity to test the relationship between YP precipitation and ocean temperature. Here, we present a new, ∼annually resolved speleothem record of stable isotope (δ18O and δ13C) and trace element (Mg/Ca and Sr/Ca) ratios for a section of the mid-Holocene (5.2–5.7 kyr BP), before extensive agriculture began in the region. A meter-long stalagmite from Río Secreto, a cave system in Playa del Carmen, Mexico, was dated using U–Th geochronology and layer counting, yielding multidecadal age uncertainty (median 2SD of ±70 years). New proxy data were compared to an existing late Holocene stalagmite record from the same cave system, allowing us to examine changes in hydrology over time and to paleoclimate records from the southern YP. The δ18O, δ13C, and Mg/Ca data consistently indicate higher mean precipitation and lower precipitation variability during the mid-Holocene compared to the late Holocene. Despite this reduced variability, multidecadal precipitation variations were persistent in regional hydroclimate during the mid-Holocene. We therefore conclude that higher summer insolation led to increased mean precipitation and decreased precipitation variability in the northern YP but that the region is susceptible to dry periods across climate mean states. Given projected decreases in wet season precipitation in the YP’s near future, we suggest that climate mitigation strategies emphasize drought preparation.
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ArticleReproducibility of Ba/Ca variations recorded by northeast Pacific bamboo corals(John Wiley & Sons, 2017-09-13) Serrato Marks, Gabriela ; LaVigne, Michèle ; Hill, Tessa M. ; Sauthoff, Wilson ; Guilderson, Thomas P. ; Roark, E. Brendan ; Dunbar, Robert B. ; Horner, Tristan J.Trace elemental ratios preserved in the calcitic skeleton of bamboo corals have been shown to serve as archives of past ocean conditions. The concentration of dissolved barium (BaSW), a bioactive nutrientlike element, is linked to biogeochemical processes such as the cycling and export of nutrients. Recent work has calibrated bamboo coral Ba/Ca, a new BaSW proxy, using corals spanning the oxygen minimum zone beneath the California Current System. However, it was previously unclear whether Ba/Cacoral records were internally reproducible. Here we investigate the accuracy of using laser ablation inductively coupled plasma mass spectrometry for Ba/Cacoral analyses and test the internal reproducibility of Ba/Ca among replicate radial transects in the calcite of nine bamboo corals collected from the Gulf of Alaska (643–720 m) and the California margin (870–2054 m). Data from replicate Ba/Ca transects were aligned using visible growth bands to account for nonconcentric growth; smoothed data were reproducible within ~4% for eight corals (n = 3 radii/coral). This intracoral reproducibility further validates using bamboo coral Ba/Ca for BaSW reconstructions. Sections of the Ba/Ca records that were potentially influenced by noncarbonate bound Ba phases occurred in regions where elevated Mg/Ca or Pb/Ca and coincided with anomalous regions on photomicrographs. After removing these regions of the records, increased Ba/Cacoral variability was evident in corals between ~800 and 1500 m. These findings support additional proxy validation to understand BaSW variability on interannual timescales, which could lead to new insights into deep sea biogeochemistry over the past several centuries.
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ThesisInvestigating Mexican paleoclimate with precisely dated speleothems(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2020-09) Serrato Marks, GabrielaSpeleothems, or sedimentary rocks formed in caves, act as valuable archives of past climate change due to their suitability for U-series dating and high-resolution proxy analysis. These records can provide insights into water availability and controls on hydrology prior to the instrumental record. In this thesis, I present three records from newly-analyzed Mexican stalagmites using stable isotope (oxygen and carbon) and trace element to calcium (Mg/Ca and Sr/Ca) ratios as proxies for changing hydroclimate. Chapter 2 presents a precisely dated, mid-Holocene record of high rainfall and limited precipitation variability in the Yucatan Peninsula, Mexico. Chapters 3 and 4 present novel climate records from northeastern Mexico, an understudied region of North America. Both records come from cave sites within the Mexican arid zone, which is simultaneously experiencing increased water scarcity and a rapidly growing population. In Chapter 3, I examine a speleothem from the first millennium of the Common Era, which showed that there is a precipitation dipole between northern and southern Mexico. Chapter 4 highlights, for the first time at decadal resolution, the northeast Mexican response to the 8.2 ka event and the Younger Dryas. These chapters show that the San Luis Potosí region is vulnerable to droughts under multiple climate mean states, and is subject to drying as Atlantic Meridional Overturning Circulation weakens due to anthropogenic climate change. The climate records detailed in this thesis improve our understanding of controls on Mexican hydroclimate and can serve as benchmarks for climate models.
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ArticleBuilding an inclusive wave in marine science: Sense of belonging and Society for Women in Marine Science symposia(Elsevier, 2023-08-30) Canfield, Katherine Nicole ; Sterling, Alexa R. ; Hernandez, Christina M. ; Chu, Sophie N. ; Edwards, Bethanie R. ; Fontaine, Diana N. ; Freese, Jillian M. ; Giroux, Marissa S. ; Jones, Aubree E. ; McCarty, Alexandra J. ; Morrissette, Hannah K. ; Palevsky, Hilary I. ; Raker, Catherine E. ; Robuck, Anna R. ; Serrato-Marks, Gabriela ; Thibodeau, Patricia S. ; Windle, Anna E.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.