Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Problem Description
• Related Publications
• Related Datasets
• Parameters
• Instruments
• Project Information
• Funding

See "Related Datasets" section for other data from these same laboratory experiments.

Spawning ripe black sea bass (BSB) were collected on May 20th, 2022 via hook and line angling in Long Island Sound off Stonington Borough, CT (41.3359°N, 71.9059°W) and brought to the University of Connecticut seawater laboratory on the Avery Point campus (Groton, CT) for future strip-spawning.  

Experimental Design:

Our experiment assessed the CO2 sensitivity of embryos and early life stages of BSB at a single static temperature (22°C) and three pCO2 conditions (~400, ~2200, ~4200 µatm). On May 23rd, 2022, we strip-spawned wild, running-ripe BSB ((Nfemale/male = 4/3) to produce viable embryos. Upon water-hardening a 5 ml sample of eggs was randomly allocated to a replicate 19-l rearing container held within one of nine recirculating systems within the Baumann labs automated larval rearing system (ALFiRiS). 

For this experiment, three ALFiRiS systems were assigned each pCO2  treatment and received eight individual replicates. Replicate containers consisted of 750 ml plastic cups with 100 µm mesh bottoms, which were floated in larger 19-l containers. 19-l containers were fitted with four 150 µm mesh screens to allow for water transfer and each 750 ml rearing container received a gravity-fed flow of treatment water to maintain embryos in the water column (4-l hour-1). For the ambient and elevated treatments each replicate ALFiRiS tank received eight 750 ml rearing containers, while two of the extreme treatments received eight rearing containers the other received 16. Actual pCO2 values were measured by taking 300 ml filtered water samples from each tank every nine days for endpoint titrations. Tank temperature, pH, and total alkalinity values were used to calculate pCO2 using CO2SYS (V2.3, Lewis and Wallace 2021; available at https://www.ncei.noaa.gov/access/ocean-carbon-acidification-data-system/oceans/CO2SYS/co2rprt.html). Throughout the experiment pH was recorded once an hour and temperature were recorded every five minutes. Additionally, ammonia (ppm) was measured once a week while salinity was measured every nine days (psu).

At 22°C hatching occurred approximately 48 hours post fertilization (hpf). Immediately, following hatch four of the eight (or eight of sixteen for one tank) replicates were euthanized with an overdose of MS-222 and immediately fixed in cold (2-4°C) paraformaldehyde (PFA) in phosphate buffered saline (PBS). The remaining replicates were reared until 10 dph, upon which they were euthanized and fixed as previously described. For the first two dph larvae were fed greenwater (RGComplete, Reed Mariculture, Campbell CA, USA) ad libitum 3× a day. Starting on 1 dph larvae were fed live L-type rotifers (Reed Mariculture, Campbell CA, USA) ad libitum 3× a day.  

Response Traits
* See "Related Datasets" section for access to morphometric data.

We estimated percent hatch at the number of hatched larvae at 0 days post hatch (dph) divided by the sum of hatched larvae and unhatched embryos × 100. Since replicate containers which were reared to 10 dph were not sampled at 0 dph to determine percent hatch, the number of embryos was estimated as the average number of embryos from the nine extra sample allocations which was then multiplied by the ALFiRiS system average hatching success to estimate total larvae at 0 dph. Subsequently, percent survival was the number of surviving larvae at 10 dph divided by the estimated number of larvae at 0 dph × 100.

At both 0 and 10 dph we individually photographed each larvae using calibrated images (Nikon SMZ1000, Image-Pro-Premier V.9.3.3) to measure individual for total length (TL; mm) and body depth (BD; mm). 10 dph larvae were also measured for notochord length (NL; mm), eye diameter (ED; mm), and mandible length (ML; mm).

Length growth rates (GR, mm d-1) were calculated by dividing the difference between replicate TL means at 0 and 10 dph by 10. 

Organism Identifier (LSID, Life Sciences Identifier)
Centropristis striata, urn:lsid:marinespecies.org:taxname:159348

Description from NSF award abstract:
Coastal marine ecosystems provide a number of important services and resources for humans, and at the same time, coastal waters are subject to environmental stressors such as increases in ocean acidification and reductions in dissolved oxygen. The effects of these stressors on coastal marine organisms remain poorly understood because most research to date has examined the sensitivity of species to one factor, but not to more than one in combination. This project will determine how a model fish species, the Atlantic silverside, will respond to observed and predicted levels of dissolved carbon dioxide (CO2) and oxygen (O2). Shorter-term experiments will measure embryo and larval survival, growth, and metabolism, and determine whether parents experiencing stressful conditions produce more robust offspring. Longer-term experiments will study the consequences of ocean acidification over the entire life span by quantifying the effects of high-CO2 conditions on the ratio of males to females, lifetime growth, and reproductive investment. These studies will provide a more comprehensive view of how multiple stressors may impact populations of Atlantic silversides and potentially other important forage fish species. This collaborative project will support and train three graduate students at the University of Connecticut and the Stony Brook University (NY), two institutions that attract students from minority groups. It will also provide a variety of opportunities for undergraduates to participate in research and the public to learn about the study, through summer research projects, incorporation in the "Women in Science and Engineering" program, and interactive displays of environmental data from monitoring buoys. The two early-career investigators are committed to increasing ocean literacy and awareness of NSF-funded research through public talks and presentations.

This project responds to the recognized need for multi-stressor assessments of species sensitivities to anthropogenic environmental change. It will combine environmental monitoring with advanced experimental approaches to characterize early and whole life consequences of acidification and hypoxia in the Atlantic silverside (Menidia menidia), a valued model species and important forage fish along most of the US east coast. Experiments will employ a newly constructed, computer-controlled fish rearing system to allow independent and combined manipulation of seawater pCO2 and dissolved oxygen (DO) content and the application of static and fluctuating pCO2 and DO levels that were chosen to represent contemporary and potential future scenarios in productive coastal habitats. First CO2, DO, and CO2 × DO dependent reaction norms will be quantified for fitness-relevant early life history (ELH) traits including pre- and post-hatch survival, time to hatch, post-hatch growth, by rearing offspring collected from wild adults from fertilization to 20 days post hatch (dph) using a full factorial design of 3 CO2 × 3 DO levels. Second, the effects of tidal and diel CO2 × DO fluctuations of different amplitudes on silverside ELH traits will be quantified. To address knowledge gaps regarding the CO2-sensitivity in this species, laboratory manipulations of adult spawner environments and reciprocal offspring exposure experiments will elucidate the role of transgenerational plasticity as a potential short-term mechanism to cope with changing environments. To better understand the mechanisms of fish early life CO2-sensitivity, the effects of temperature × CO2 on pre- and post-hatch metabolism will be robustly quantified. The final objective is to rear silversides from fertilization to maturity under different CO2 levels and assess potential CO2-effects on sex ratio and whole life growth and fecundity.

Related references:
Gobler, C.J. and Baumann, H. (2016) Hypoxia and acidification in ocean ecosystems: Coupled dynamics and effects on marine life. Biology Letters 12:20150976. doi:10.1098/rsbl.2015.0976

Baumann, H. (2016) Combined effects of ocean acidification, warming, and hypoxia on marine organisms. Limnology and Oceanography e-Lectures 6:1-43. doi:10.1002/loe2.10002

Depasquale, E., Baumann, H., and Gobler, C.J. (2015) Variation in early life stage vulnerability among Northwest Atlantic estuarine forage fish to ocean acidification and low oxygen Marine Ecology Progress Series 523: 145–156.doi:10.3354/meps11142

NSF Abstract:

Oceans are large, open habitats, and it was previously believed that their lack of obvious barriers to dispersal would result in extensive mixing, preventing organisms from adapting genetically to particular habitats. It has recently become clear, however, that many marine species are subdivided into multiple populations that have evolved to thrive best under contrasting local environmental conditions. Nevertheless, we still know very little about the genomic mechanisms that enable divergent adaptations in the face of ongoing intermixing. This project focuses on the Atlantic silverside (Menidia menidia), a small estuarine fish that exhibits a remarkable degree of local adaptation in growth rates and a suite of other traits tightly associated with a climatic gradient across latitudes. Decades of prior lab and field studies have made Atlantic silverside one of the marine species for which we have the best understanding of evolutionary tradeoffs among traits and drivers of selection causing adaptive divergence. Yet, the underlying genomic basis is so far completely unknown. The investigators will integrate whole genome sequencing data from wild fish sampled across the distribution range with breeding experiments in the laboratory to decipher these genomic underpinnings. This will provide one of the most comprehensive assessments of the genomic basis for local adaptation in the oceans to date, thereby generating insights that are urgently needed for better predictions about how species can respond to rapid environmental change. The project will provide interdisciplinary training for a postdoc as well as two graduate and several undergraduate students from underrepresented minorities. The findings will also be leveraged to develop engaging teaching and outreach materials (e.g. a video documentary and popular science articles) to promote a better understanding of ecology, evolution, and local adaptation among science students and the general public.

The goal of the project is to characterize the genomic basis and architecture underlying local adaptation in M. menidia and examine how the adaptive divergence is shaped by varying levels of gene flow and maintained over ecological time scales. The project is organized into four interconnected components. Part 1 examines fine-scale spatial patterns of genomic differentiation along the adaptive cline to a) characterize the connectivity landscape, b) identify genomic regions under divergent selection, and c) deduce potential drivers and targets of selection by examining how allele frequencies vary in relation to environmental factors and biogeographic features. Part 2 maps key locally adapted traits to the genome to dissect their underlying genomic basis. Part 3 integrates patterns of variation in the wild (part 1) and the mapping of traits under controlled conditions (part 2) to a) examine how genomic architectures underlying local adaptation vary across gene flow regimes and b) elucidating the potential role of chromosomal rearrangements and other tight linkage among adaptive alleles in facilitating adaptation. Finally, part 4 examines dispersal - selection dynamics over seasonal time scales to a) infer how selection against migrants and their offspring maintains local adaptation despite homogenizing connectivity and b) validate candidate loci for local adaptation. Varying levels of gene flow across the species range create a natural experiment for testing general predictions about the genomic mechanisms that enable adaptive divergence in the face of gene flow. The findings will therefore have broad implications and will significantly advance our understanding of the role genomic architecture plays in modifying the gene flow - selection balance within coastal environments.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.