More Like this

1. You Better Repeat It: Complex CO2 × Temperature Effects in Atlantic Silverside Offspring Revealed by Serial Experimentation

   https://doi.org/10.3390/d10030069  

   Murray, Christopher ; Baumann, Hannes ( September 2018 , Diversity)

   null (Ed.)

   Concurrent ocean warming and acidification demand experimental approaches that assess biological sensitivities to combined effects of these potential stressors. Here, we summarize five CO2 × temperature experiments on wild Atlantic silverside, Menidia menidia, offspring that were reared under factorial combinations of CO2 (nominal: 400, 2200, 4000, and 6000 µatm) and temperature (17, 20, 24, and 28 °C) to quantify the temperature-dependence of CO2 effects in early life growth and survival. Across experiments and temperature treatments, we found few significant CO2 effects on response traits. Survival effects were limited to a single experiment, where elevated CO2 exposure reduced embryo survival at 17 and 24 °C. Hatch length displayed CO2 × temperature interactions due largely to reduced hatch size at 24 °C in one experiment but increased length at 28 °C in another. We found no overall influence of CO2 on larval growth or survival to 9, 10, 15 and 13–22 days post-hatch, at 28, 24, 20, and 17 °C, respectively. Importantly, exposure to cooler (17 °C) and warmer (28 °C) than optimal rearing temperatures (24 °C) in this species did not appear to increase CO2 sensitivity. Repeated experimentation documented substantial inter- and intra-experiment variability, highlighting the need for experimental replication to more robustly constrain inherently variable responses. Taken together, these results demonstrate that the early life stages of this ecologically important forage fish appear largely tolerate to even extreme levels of CO2 across a broad thermal regime. 

   more » « less
2. Oxygen supply capacity in animals evolves to meet maximum demand at the current oxygen partial pressure regardless of size or temperature

   https://doi.org/10.1101/701417  

   Seibel, B. ( January 2020 , Journal of experimental biology)

   null (Ed.)

   The capacity to extract oxygen from the environment and transport it to respiring tissues in support of metabolic demand reportedly has implications for species’ thermal tolerance, body size, diversity and biogeography. Here, we derived a quantifiable linkage between maximum and basal metabolic rate and their oxygen, temperature and size dependencies. We show that, regardless of size or temperature, the physiological capacity for oxygen supply precisely matches the maximum evolved demand at the highest persistently available oxygen pressure and this is the critical PO2 for the maximum metabolic rate, Pcrit-max. For most terrestrial and shallow-living marine species, Pcrit-max is the current atmospheric pressure, 21 kPa. Any reduction in oxygen partial pressure from current values will result in a calculable decrement in maximum metabolic performance. However, oxygen supply capacity has evolved to match demand across temperatures and body sizes and so does not constrain thermal tolerance or cause the well-known reduction in mass-specific metabolic rate with increasing body mass. The critical oxygen pressure for resting metabolic rate, typically viewed as an indicator of hypoxia tolerance, is, instead, simply a rate-specific reflection of the oxygen supply capacity. A compensatory reduction in maintenance metabolic costs in warm-adapted species constrains factorial aerobic scope and the critical PO2 to a similar range, between ∼2 and 6, across each species’ natural temperature range. The simple new relationship described here redefines many important physiological concepts and alters their ecological interpretation. 

   more » « less
3. Temperature but not ocean acidification affects energy metabolism and enzyme activities in the blue mussel, Mytilus edulis

   https://doi.org/10.1002/ece3.7289  

   Matoo, Omera B. ; Lannig, Gisela ; Bock, Christian ; Sokolova, Inna M. ( March 2021 , Ecology and Evolution)

   In mosaic marine habitats, such as intertidal zones, ocean acidification (OA) is exacerbated by high variability of pH, temperature, and biological CO₂production. The nonlinear interactions among these drivers can be context‐specific and their effect on organisms in these habitats remains largely unknown, warranting further investigation.

   We were particularly interested inMytilus edulis(the blue mussel) from intertidal zones of the Gulf of Maine (GOM), USA, for this study. GOM is a hot spot of global climate change (average sea surface temperature (SST) increasing by >0.2°C/year) with >60% decline in mussel population over the past 40 years.

   Here, we utilize bioenergetic underpinnings to identify limits of stress tolerance inM. edulisfrom GOM exposed to warming and OA. We have measured whole‐organism oxygen consumption rates and metabolic biomarkers in mussels exposed to control and elevated temperatures (10 vs. 15°C, respectively) and current and moderately elevatedP_CO2levels (~400 vs. 800 µatm, respectively).

   Our study demonstrates that adultM. edulisfrom GOM are metabolically resilient to the moderate OA scenario but responsive to warming as seen in changes in metabolic rate, energy reserves (total lipids), metabolite profiles (glucose and osmolyte dimethyl amine), and enzyme activities (carbonic anhydrase and calcium ATPase).

   Our results are in agreement with recent literature that OA scenarios for the next 100–300 years do not affect this species, possibly as a consequence of maintaining its in vivo acid‐base balance.

    

   more » « less
4. Ice-Tethered Profiler Biogeochemical Time-Series Data, Arctic Ocean, 2012-2021

   https://doi.org/10.18739/A2B853K2R  

   DeGrandpre, Michael ( January 2022 , NSF Arctic Data Center)

   The goal of the proposed study is to establish an Arctic Observing Network (AON) for sea surface partial pressure of carbon dioxide (pCO2) and pH in the perennially ice-covered portion of the Arctic Ocean. The carbon cycle is of particular concern in the Arctic because it is unknown how carbon sources and sinks will change in response to warming and the reduction of summer sea ice cover, and whether these changes will lead to increased greenhouse gas accumulation in the atmosphere. Furthermore, the penetration of anthropogenic caron dioxide (CO2) into the Arctic Ocean is leading to acidification with potentially serious consequences for organisms. Little is known about pCO2 and the inorganic carbon cycle in the central Arctic Ocean because most measurement programs to date have focused on the Arctic shelves during the accessible summer period. The investigators propose to use an existing component of the Arctic Observing Network, the Ice-Tethered Profilers (ITP), as platforms for deployment of in situ pCO2 and pH sensors. ITPs are automated profiling systems distributed throughout the perennial Arctic ice pack that telemeter data back to shore: 44 ITPs have been deployed since 2004 and the project is currently slated to continue through 2013. In the proposed work, a total of 6 ITPs will be equipped with CO2 sensors and four of these will also have pH sensors. The sensors will be fixed on the ITP cable ~2-4 meters below the ice. Each unit will include additional sensors for dissolved O2, salinity, and photosynthetically available radiation (and in some cases chlorophyll-a fluorescence) and will be capable of making 12 measurements per day for at least one year. These data, available in near real-time on the ITP web site (www.whoi.edu/itp/), will lead to a better understanding of the Arctic Ocean's role in regulating greenhouse gases and how the ecology of the Arctic will change with warming and acidification. The investigators will also engage in outreach programs including public presentations, podcasts, and school visits. A portion of the budget is also dedicated to the development of a climate-change/ocean acidification exhibit to be displayed in the University of Montana's science museum. The exhibit will reside at the museum for three months, then visit over 15 rural and tribal communities annually over a three year period. Undergraduate students will be recruited to assist with the sensor testing and data analysis, gaining a higher level of technical knowledge than possible through a traditional degree program. These data were collected using in situ sensors for the partial pressure of CO2 (pCO2), pH, dissolved oxygen (DO), photosynthetically available radiation (PAR), temperature, salinity and depth. Sensors were deployed at ~6 meter depth on ice-tethered profilers, in collaboration with Woods Hole Oceanographic Institution (Rick Krishfield and John Toole). Data are available at the website http://www.whoi.edu/page.do?pid=20781. 

   more » « less
5. Consequences of elevated CO2 exposure across multiple life stages in a coastal forage fish

   https://doi.org/10.1093/icesjms/fsw179  

   Murray, Christopher S. ; Fuiman, Lee A. ; Baumann, Hannes ( October 2016 , ICES Journal of Marine Science)

   Browman, Howard (Ed.)

   Ocean acidification may impact the fitness of marine fish, however, studies reporting neutral to moderate effects have mostly performed short-term exposures to elevated CO2, whereas longer-term studies across life stages are still scarce. We performed a CO2 exposure experiment, in which a large number (n > 2200) of Atlantic silverside Menidia menidia offspring from wild spawners were reared for 135 days through their embryonic, larval, and juvenile stages under control (500 µatm) and high CO2 conditions (2300 µatm). Although survival was high across treatments, subtle but significant differences in length, weight, condition factor and fatty acid (FA) composition were observed. On average, fish from the acidified treatment were 4% shorter and weighed 6% less, but expressed a higher condition factor than control juveniles. In addition, the metrics of length and weight distributions differed significantly, with juveniles from the high CO2 treatment occupying more extreme size classes and the length distribution shifting to a positive kurtosis. Six of twenty-seven FAs differed significantly between treatments. Our results suggest that high CO2 conditions alter long-term growth in M. menidia, particularly in the absence of excess food. It remains to be shown whether and how these differences will impact fish populations in the wild facing size-selective predation and seasonally varying prey abundance. 

   more » « less