The impact of anthropogenic climate change on terrestrial organisms is often predicted to increase with latitude, in parallel the rate warming. Yet biological rising temperatures also depends physiological sensitivity temperature change. We integrate empirical fitness curves describing thermal tolerance insects from around world projected geographic distribution for next century estimate direct warming insect across latitude. results show that tropics, although relatively small magnitude,...

Insect pests substantially reduce yields of three staple grains-rice, maize, and wheat-but models assessing the agricultural impacts global warming rarely consider crop losses to insects. We use established relationships between temperature population growth metabolic rates insects estimate how where climate will augment rice, wheat Global yield these grains are projected increase by 10 25% per degree mean surface warming. Crop be most acute in areas increases both These conditions centered...

Biological impacts of climate warming are predicted to increase with latitude, paralleling increases in warming. However, the magnitude depends not only on degree but also number species at risk, their physiological sensitivity and options for behavioural compensation. Lizards useful evaluating risks because thermal biology is well studied. We conducted macrophysiological analyses diurnal lizards from diverse latitudes plus focal Puerto Rican Anolis Sphaerodactyus. Although tropical lowland...

Warming of the oceans and consequent loss dissolved oxygen (O2) will alter marine ecosystems, but a mechanistic framework to predict impact multiple stressors on viable habitat is lacking. Here, we integrate physiological, climatic, biogeographic data calibrate then map key metabolic index-the ratio O2 supply resting demand-across geographic ranges several ectotherms. These species differ in thermal hypoxic tolerances, their contemporary distributions are all bounded at equatorward edge by...

Oxygen (O(2)) is a critical constraint on marine ecosystems. As oceanic O(2) falls to hypoxic concentrations, habitability for aerobic organisms decreases rapidly. We show that the spatial extent of hypoxia highly sensitive small changes in ocean's content, with maximum responses at suboxic concentrations where anaerobic metabolisms predominate. In model-based reconstructions historical oxygen changes, world's largest zone, Pacific Ocean, varies size by factor 2. This attributable...

Drivers of the “Great Dying” Though our current extinction crisis is substantial, it pales in comparison to largest Earth's history, which occurred at end Permian Period. Referred as Dying,” this event saw loss up 96% all marine species and 70% terrestrial species. Penn et al. explored dynamics time using Earth system models conjunction with physiological data across animal taxa (see Perspective by Kump). They conclude that increased temperatures reduced oxygen availability were responsible...

Abstract Historic observations of dissolved oxygen (O 2 ) in the ocean are analyzed to quantify multidecadal trends and variability from 1958 2015. Additional quality control is applied, resultant anomaly field used upper O at global hemispheric scales. A widespread negative trend beginning emerge envelope interannual variability. Ocean reanalysis data evaluate relationships with changes heat content (OHC) solubility 2,sat ). Global decline evident after 1980s, accompanied by an increase...

Abstract Anthropogenically forced trends in oceanic dissolved oxygen are evaluated Earth system models the context of natural variability. A large ensemble a single model is used to clearly identify component change interior distributions and evaluate magnitude this signal relative noise generated by internal climate The time emergence quantified on basis anomalies concentrations trends. We find that should already be evident southern Indian Ocean parts eastern tropical Pacific Atlantic...

Significance Organic particles that sink to the deep ocean release carbon dioxide in waters remain out of contact with atmosphere on long timescales. This paper reconstructs particle flux profiles from large-scale nutrient distributions, revealing systematic regional variations have proved difficult detect direct observations alone. We show “transfer efficiency” organic matter depth is greatest high-latitude regions and lowest subtropics, well explained by phytoplankton community structure....

We establish the fixed nitrogen budget of Pacific Ocean based on nutrient fields from recently completed World Circulation Experiment (WOCE). The includes denitrification in water column and sediments, fixation, atmospheric riverine inputs, divergence due to large‐scale circulation. A rate 48±5 Tg N yr −1 is calculated for Eastern Tropical using N* [ Gruber Sarmiento , 1997] mass age tracers. On basis rates literature, we estimate sedimentary remove an additional 15±3 . then calculate total...

We investigate the response of 15 N/ 14 N oceanic nitrate to glacial/interglacial changes in budget, using a geochemical box model cycle that includes 2 fixation and denitrification sediments suboxic water column. This allows us quantify isotopic different pools deglacial increases column sedimentary denitrification, given range possible feedbacks between concentration fixation/denitrification. is compared available paleoceanographic data, which suggest an early maximum zones no significant...

The conversion of dissolved nutrients and carbon to organic matter by phytoplankton in the surface ocean, its downward transport sinking particles, produces a “biological pump” that reduces concentration atmospheric CO 2 . Global rates export are poor indicator biological storage however, because gets distributed across water masses with diverse pathways timescales return surface. Here we show can be related through sequestration efficiency, which measures how long regenerated will stored...

Climate warming is expected to reduce oxygen (O2) supply the ocean and expand its minimum zones (OMZs). We reconstructed variations in extent of North Pacific anoxia since 1850 using a geochemical proxy for denitrification (δ(15)N) from multiple sediment cores. Increasing δ(15)N ~1990 records an expansion anoxia, consistent with observed O2 trends. However, this was preceded by longer declining trend that implies anoxic zone shrinking most 20th century. Both periods can be explained changes...

Bubbles play an important role in the exchange of gases between atmosphere and ocean, altering both rate equilibrium gas saturation state. We develop a parameterization bubble‐mediated fluxes for use Earth system models. The is derived from mechanistic model oceanic boundary layer that simulates turbulent flows size spectrum bubbles across range wind speeds compared against other published formulations. Bubble‐induced surface supersaturation increases rapidly with speed inversely related to...

Abstract. A major impediment to understanding long-term changes in the marine nitrogen (N) cycle is persistent uncertainty about rates, distribution, and sensitivity of its largest fluxes modern ocean. We use a global ocean circulation model obtain first 3-D estimate denitrification rates that maximally consistent with available observations nitrate deficits isotopic ratio oceanic nitrate. find rate suboxic waters sediments 120–240 Tg N yr−1, which lower than many other recent estimates. The...

N and O isotope analyses of water column nitrate between Bermuda Puerto Rico document a bolus low‐ δ 15 throughout the Sargasso Sea thermocline, which we attribute primarily to input recently fixed N. Although previous work suggests southward increases in 2 fixation ventilation age, no meridional trend is apparent. In upper 200 m, algal uptake‐driven increase 18 greater than N, because (1) higher fraction from at shallower depths and/or (2) cycling assimilation nitrification. A mean depth...