Oxygen metrics for retinal function in marine invertebrate larvae determined with electroretinograms

Oxygen metrics for retinal function in marine invertebrate larvae determined with electroretinograms

Please see additional datasets for this paper, including the "RetinalResponse TimeSeries" and the "Experiment Metrics" datasets.

Acquisition Description
Detailed methods can be found in McCormick, LR; Levin, LA; Oesch, NW. 2019.Vision is highly sensitive to oxygen availability in marine invertebrate larvae.Journal of Experimental Biology 222, jeb200899. doi:10.1242/jeb.200899.Data shown in Figure 1, bottom panel.
Briefly, the time series test recorded electroretinogram (ERG) responses to a 1 s square step of light at a constant irradiance of 3.56 μmol photons m−2 s−1 repeated every 20 s, providing a nearly continuous measure of ERG response in a tethered, live larva during the experimental manipulation of partial pressure of oxygen (pO2).There was a constant flow of pH-buffered sterile seawater in the chamber where the larva was held, and after a brief period in "normoxia" (surface-ocean oxygen levels), the pO2 was decreased, and then held at a low pO2 before reoxygenating the solution.This dataset shows the three visual metrics that were calculated to quantify the effects of reduced pO2 on retinal function.V90, V50, and V10 were calculated for each individual larva as the oxygen where there was 90%, 50%, and 10% retinal function remaining, in respect to retinal responses in normoxia (surface-ocean oxygen levels).
Oxygen was measured using a Microx4 (PreSens) oxygen meter and a Pst-7 oxygen optode probe.

Processing Description
All electrophysiology data was recorded and analyzed using Igor Pro 7 Software (Wavemetrics) using custom code.Oxygen data was analyzed using PreSens Measurement Studio 2. Post-processing analysis was completed in R Studio (version 3.3.3).

Project Information Vision-mediated influence of low oxygen on the physiology and ecology of marine larvae (Vision under hypoxia)
Coverage: Souther California Bight, Northeast Pacific Ocean NSF abstract: Oxygen is being lost in the ocean worldwide as a result of ocean warming and the input of nutrients from land.Vision requires a large amount of oxygen, and may be less effective or require more light when oxygen is in short supply.This is especially true for active marine animals with complex eyes and visual capabilities, including active arthropods (crabs), cephalopods (squid), and fish.The California coastal waters exhibit a sharp drop in oxygen and light with increasing water depth.This project examines how visual physiology and ecology in young (larval) highly visual marine animals respond to oxygen loss, with a focus on key fisheries and aquaculture species.Experiments and observations will test the hypothesis that oxygen stress will change the light required for these organisms to see effectively, influencing the water depths where they can live and survive.The project will provide interdisciplinary experiences to students and an early career scientist and inform both the public (through outreach at the Birch Aquarium at Scripps Institution of Oceanography) and policy makers about the effects of oxygen decline in the ocean.Negative effects of oxygen loss on vision have been described for humans and other terrestrial organisms, but never in the marine environment, despite the large changes in oxygen that can occur with depth and over time in the ocean, and the high metabolic demand of visual systems.This project will test the -type dissolved oxygen instrument, including glass microsensors with minute tips (diameters ranging from 1 to 800 um).A gold or platinum sensing cathode is polarized against an internal reference and, driven by external partial pressure, oxygen from the environment penetrates through the sensor tip membrane and is reduced at the sensing cathode surface.A picoammeter converts the resulting reduction current to a signal.The size of the signal generated by the electrode is proportional to the flux of oxygen molecules to the cathode.The sensor also includes a polarized guard cathode, which scavenges oxygen in the electrolyte, thus minimizing zero-current and prepolarization time.With the addition of a meter and a sample chamber, the respiration of a small specimen can be measured.Example: Strathkelvin Inst.http://www.strathkelvin.com[table of contents | back to top ] effects of low oxygen on vision in 3 combinations of eye design and photo-transduction mechanisms: compound eye with rhabdomeric photoreceptors (arthropods), simple eye with rhabdomeric photoreceptors (cephalopods), and simple eye with ciliary photoreceptors (fish).A series of oxygen-and light-controlled laboratory experiments will be conducted on representative taxa of each group including the tuna crab, Pleuroncodes planipes; the market squid, Doryteuthis opalescens, and the white sea bass, Atractoscion nobilis.In vivo electrophysiology and behavioral phototaxis experiments will identify new oxygen metrics for visual physiology and function, and will be compared to metabolic thresholds determined in respiration experiments.Hydrographic data collected over 3 decades by the CalCOFI program in the Southern California Bight will be evaluated with respect to visual and metabolic limits to determine the consequences of oxygen variation on the critical luminoxyscape (range of oxygen and light conditions required for visual physiology and function in target species) boundary in each species.Findings for the three vision-based functional groups may test whether oxygen-limited visual responses offer an additional explanation for the shoaling of species distributions among highly visual pelagic taxa in low oxygen, and will help to focus future research efforts and better understand the stressors contributing to habitat compression with expanding oxygen loss in the ocean.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.[table of contents | back to top ]FundingFunding Source AwardNSF Division of Ocean Sciences (NSF OCE) OCE-1829623 . Vision is highly sensitive to oxygen availability in marine invertebrate larvae.The Journal of Experimental Biology, 222(10), jeb200899.doi:10.1242/jeb.200899[ table of contents | back to top ]