Abstract:

This study investigated the impacts of abiotic (low salinity, pH, and dissolved oxygen [DO]) and biotic (HAB) stressors on early life stages of oysters. Hatchery-spawned and fertilized oyster larvae were exposed to various levels of salinity, pH, DO, and microcystin-LR, a toxin produced by HABs. Growth and survival of larvae were measured following exposure. Then, hatchery-reared juvenile oysters (<10 mm) from the same spawn as the larvae were exposed to the EC50 concentration of the most sensitive response variable determined for each of the stressors tested in the larval assay. Growth and survival were measured following lab exposure to the stressors and juveniles were then transplanted to a field site at St. Stanislaus High School in Bay St. Louis, Mississippi. Growth and survival were measured biweekly during field deployment for 2 months. In situ salinity, pH, dissolved oxygen (mg/L), and temperature (°C) were recorded throughout the field deployment via HOBOware data loggers. The results of this study will improve our understanding of how chronic and acute environmental stressors affect early life stages of oysters. This dataset supports the publication: Pruett, Jessica L., Ann Fairly Pandelides, Kristine L. Willett, and Deborah J. Gochfeld. 2021. Effects of flood-associated stressors on growth and survival of early life stage oysters (Crassostrea virginica). Journal of Experimental Marine Biology and Ecology 544, 151615. DOI: 10.1016/j.jembe.2021.151615

Suggested Citation:

Pruett, Jessica L., Ann Fairly Pandelides, and Deborah J. Gochfeld. 2021. Dataset for: Effects of flood-associated stressors on growth and survival of early life stage oysters (Crassostrea virginica). Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/1AGW7HQZ

Publications:

Pruett, J. L., Pandelides, A. F., Willett, K. L., & Gochfeld, D. J. (2021). Effects of flood-associated stressors on growth and survival of early life stage oysters (Crassostrea virginica). Journal of Experimental Marine Biology and Ecology, 544, 151615. doi:10.1016/j.jembe.2021.151615

Purpose:

Oyster reefs in the northern Gulf of Mexico (GoM) were once among the world’s most productive, but have experienced significant declines, largely due to overfishing. In recent years, oyster reefs in the GoM have been increasingly exposed to stressors related to climate change, including ocean acidification and increased precipitation that results in extreme flooding events. In addition, eutrophication caused by this increased freshwater runoff has caused hypoxic events and harmful algal blooms (HABs) that threaten oyster reef survival and the success of restoration efforts. Many studies have assessed the effects of these stressors on adult oysters, whereas the health and survival of early life history stages represents a critical bottleneck for the future of oyster reefs. This study investigated the impacts of abiotic (low salinity, pH, and dissolved oxygen [DO]) and biotic (HABs) stressors on early life stages of oysters to improve our understanding of chronic and acute environmental stressors on larval and juvenile oysters.

Data Parameters and Units:

‘Larval Assay’ Tab headers include: Exposure Date (mm/dd/yyyy); Stressor; Replicate ID (A/B/C/D); Exposure Concentration (salinity [ppt], dissolved oxygen [DO, mg/L], pH, microcystin-LR [MC-LR, μg/L]); Endpoints: larval growth (𝛍m^2/day); survival proportional ‘Seed Assay – Lab’ Tab headers include: Stressor; Replicate ID (A/B/C/D); Average Exposure Concentration (salinity [ppt], dissolved oxygen [DO, mg/L], pH, microcystin-LR [MC-LR, μg/L]); Shell growth (mm^2/day); Change in wet weight (mg) ‘Seed Assay- Field Growth’ Tab headers include: Lab Stressor; Replicate ID (A/B/C/D/E); Average shell growth (mm^2/day); Average change in wet weight (mg); Average survival- proportional ‘Seed Assay- Field Survival’ Tab headers include: Week #; Lab Stressor; Replicate ID (A/B/C/D/E); Survival- proportional ‘Field Water Quality’ Tab headers include: Date/Time (mm/dd/yyy hh/mm); Salinity (ppt); pH; DO (mg/L); Temp (°C)

Methods:

Exposure concentrations: DO levels were quantified with a fiber optic oxygen probe (OXROB10) connected to a FireSting O2 meter (FSO2-4, PyroScience, Aachen, Germany). pH and temperature were measured using a HOBO® pH and temperature logger (MX2501, Onset Computer, Bourne, MA, USA), which was calibrated using NIST-traceable buffer solutions. Salinity was measured with a refractometer. Water samples (1 mL) were collected from MC-LR treatment containers prior to the addition of food to analyze MC-LR concentrations using liquid chromatography tandem mass spectrometry (UPLC-MS/MS; Alliance UPLC with Xevo TQD, Waters Corporation, Milford, MA, USA) methods at the University of Mississippi’s Chemistry and Drug Metabolism Pharmacokinetics Core. During the Larval Assays, subsamples were taken from each treatment replicate and larvae were counted either dead or alive by Sedgwick-Rafter counting chamber to calculate proportional survival. Photos of preserved larvae from each treatment replicate were analyzed using ImageJ software to measure shell area and calculate larval shell growth. At the start and end of the Seed Assays, wet weights and photographs of individually labeled juveniles were taken. Photos were used to measure initial and final shell areas with ImageJ software in order to calculate shell growth. During field deployment, baskets were shaken weekly to remove sediment and epibionts and opened biweekly to record survival. Wet weights and photos of juveniles were obtained at the end of the field deployment to calculate growth. During field deployment, HOBO® loggers were used to record DO (U26-001), pH (MX2501), and salinity (U24-002-C) at 5-min intervals. All three loggers recorded temperature but only temperature from the pH logger was reported. Loggers were attached to a sensor platform that was deployed on the bottom at the site of the juvenile deployment. The field deployment took place from 2020-09-01 to 2020-10-27. The sensor platform was removed from the water between 2020-09-14 through 2020-09-17 and again 2020-10-08 to 2020-10-12, due to hurricanes. Data were also not collected between 2020-09-30 to 2020-10-06, due to sensor platform maintenance.

Instruments:

FireSting O2 meter (FSO2-4, PyroScience, Aachen, Germany); fiber optic oxygen probe (OXROB10); HOBO® pH and temperature logger (MX2501, Onset Computer, Bourne, MA, USA); refractometer; liquid chromatography tandem mass spectrometry (UPLC-MS/MS; Alliance UPLC with Xevo TQD, Waters Corporation, Milford, MA, USA); ImageJ software

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