Laboratory studies indicate that plant respiratory efficiency may decrease in response to low nutrient availability due to increased partitioning of electrons to the energy-wasteful alternative oxidase (AOX); however, field confirmation of this hypothesis is lacking. We therefore investigated plant respiratory changes associated with succession and retrogression in soils aged from 10 to 120000 years along the Franz Josef soil chronosequence, New Zealand. Respiration rates and electron partitioning were determined based on oxygen isotopic fractionation. Leaf structural traits, foliar nutrient status, carbohydrates and species composition were measured as explanatory variables. Although soil nutrient levels and species composition varied by site along the chronosequence, foliar respiration across all sites and species corresponded strongly with leaf nitrogen concentration (r2=0.8). In contrast, electron partitioning declined with increasing nitrogen/phosphorus (r2=0.23) and AOX activity correlated with phosphorus (r2=0.64). Independently, total respiration was further associated with foliar Cu, possibly linked to its effect on AOX. Independent control of AOX and cytochrome pathway activities is also discussed. These responses of plant terminal respiratory oxidases and therefore respiratory carbon efficiency to multiple nutrient deficiencies demonstrate that modulation of respiratory metabolism may play an important role in plant responses to nutrient gradients.

Previous studies have suggested that solar-induced chlorophyll fluorescence (SIF) is correlated with Gross Primary Production (GPP). However, it remains unclear to what extent this relationship is due to absorbed photosynthetically active radiation (APAR) and/or light use efficiency (LUE). Here we present the first time series of near-surface measurement of canopy-scale SIF at 760nm in temperate deciduous forests. SIF correlated with GPP estimated with eddy covariance at diurnal and seasonal scales (r(2)=0.82 and 0.73, respectively), as well as with APAR diurnally and seasonally (r(2)=0.90 and 0.80, respectively). SIF/APAR is significantly positively correlated with LUE and is higher during cloudy days than sunny days. Weekly tower-based SIF agreed with SIF from the Global Ozone Monitoring Experiment-2 (r(2)=0.82). Our results provide ground-based evidence that SIF is directly related to both APAR and LUE and thus GPP, and confirm that satellite SIF can be used as a proxy for GPP.

Recent advances in the retrieval of Chl fluorescence from space using passive methods (solar- induced Chl fluorescence, SIF) promise improved mapping of plant photosynthesis globally. However, unresolved issues related to the spatial, spectral, and temporal dynamics of vegetation fluorescence complicate our ability to interpret SIF measurements.

Although ectomycorrhizal fungi have well-recognized effects on ecological processes ranging from plant community dynamics to carbon cycling rates, it is unclear if plants are able to actively influence the structure of these fungal communities. To address this knowledge gap, we performed two complementary experiments to determine (1) whether ectomycorrhizal plants can discriminate among potential fungal partners, and (2) to what extent the plants might reward better mutualists. In experiment 1, split-root Larix occidentalis seedlings were inoculated with spores from three Suillus species (S. clintonianus, S. grisellus, and S. spectabilis). In experiment 2, we manipulated the symbiotic quality of Suillus brevipes isolates on split-root Pinus muricata seedlings by changing the nitrogen resources available, and used carbon-13 labeling to track host investment in fungi. In experiment 1, we found that hosts can discriminate in multi-species settings. The split-root seedlings inhibited colonization by S. spectabilis whenever another fungus was available, despite similar benefits from all three fungi. In experiment 2, we found that roots and fungi with greater nitrogen supplies received more plant carbon. Our results suggest that plants may be able to regulate this symbiosis at a relatively fine scale, and that this regulation can be integrated across spatially separated portions of a root system.

The concepts that we generally associate with the field of data science are strikingly descriptive of the way that life, in general, processes information about its environment. The 'information life cycle', which enumerates the stages of information treatment in data science endeavours, also captures the steps of data collection and handling in biological systems. Similarly, the 'data-information-knowledge ecosystem', developed to illuminate the role of informatics in translating raw data into knowledge, can be a framework for understanding how information is constantly being transferred between life and the environment. By placing the principles of data science in a broader biological context, we see the activities of data scientists as the latest development in life's ongoing journey to better understand and predict its environment. Finally, we propose that informatics frameworks can be used to understand the similarities and differences between abiotic complex evolving systems and life.

The timing of delivery and the types of body that contributed volatiles to the terrestrial planets remain highly debated1,2. For example, it is unknown if differentiated bodies, such as that responsible for the Moon-forming giant impact, could have delivered substantial volatiles3,4 or if smaller, undifferentiated objects were more probable vehicles of water delivery5-7. Here we show that the water contents of minerals in achondrite meteorites (mantlesorcrusts of differentiated planetesimals) from both the inner and outer portions of the early Solar System are ≤2mugg-1H2O. These are among the lowest values ever reported for extraterrestrial minerals. Our results demonstrate that differentiated planetesimals efficiently degassed before or during melting. This finding implies that substantial amounts of water could only have been delivered to Earth by means of unmelted material.

Symbiotic cnidarians such as corals and anemones form highly productive and biodiverse coral reef ecosystems in nutrient-poor ocean environments, a phenomenon known as Darwin's paradox. Resolving this paradox requires elucidating the molecular bases of efficient nutrient distribution and recycling in the cnidarian-dinoflagellate symbiosis. Using the sea anemone Aiptasia, we show that during symbiosis, the increased availability of glucose and the presence of the algae jointly induce the coordinated up-regulation and relocalization of glucose and ammonium transporters. These molecular responses are critical to support symbiont functioning and organism-wide nitrogen assimilation through glutamine synthetase/glutamate synthase-mediated amino acid biosynthesis. Our results reveal crucial aspects of the molecular mechanisms underlying nitrogen conservation and recycling in these organisms that allow them to thrive in the nitrogen-poor ocean environments.

We present the discovery of TOI-5205b, a transiting Jovian planet orbiting a solar metallicity M4V star, which was discovered using Transiting Exoplanet Survey Satellite photometry and then confirmed using a combination of precise radial velocities, ground-based photometry, spectra, and speckle imaging. TOI-5205b has one of the highest mass ratios for M-dwarf planets, with a mass ratio of almost 0.3%, as it orbits a host star that is just 0.392 +/- 0.015 M (circle dot). Its planetary radius is 1.03 +/- 0.03 R (J), while the mass is 1.08 +/- 0.06 M (J). Additionally, the large size of the planet orbiting a small star results in a transit depth of similar to 7%, making it one of the deepest transits of a confirmed exoplanet orbiting a main-sequence star. The large transit depth makes TOI-5205b a compelling target to probe its atmospheric properties, as a means of tracing the potential formation pathways. While there have been radial-velocity-only discoveries of giant planets around mid-M dwarfs, this is the first transiting Jupiter with a mass measurement discovered around such a low-mass host star. The high mass of TOI-5205b stretches conventional theories of planet formation and disk scaling relations that cannot easily recreate the conditions required to form such planets.

Mechanical compression drives activated muscle stem cells (MuSCs) into a quiescent stem cell state providing insight into MuSC activity during injury-regeneration cycles.

In 2011, Lake Erie experienced the largest harmful algal bloom in its recorded history, with a peak intensity over three times greater than any previously observed bloom. Here we show that long-term trends in agricultural practices are consistent with increasing phosphorus loading to the western basin of the lake, and that these trends, coupled with meteorological conditions in spring 2011, produced record-breaking nutrient loads. An extended period of weak lake circulation then led to abnormally long residence times that incubated the bloom, and warm and quiescent conditions after bloom onset allowed algae to remain near the top of the water column and prevented flushing of nutrients from the system. We further find that all of these factors are consistent with expected future conditions. If a scientifically guided management plan to mitigate these impacts is not implemented, we can therefore expect this bloom to be a harbinger of future blooms in Lake Erie.