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The population of the critically endangered North Atlantic right whale, Eubalaena glacialis, numbers approximately 336 individuals, and continues to decline. Current development and implementation of protection measures and monitoring of right whale presence relies on visual surveys from vessel and aerial platforms, and passive acoustic monitoring, which contribute to location data. Here we demonstrate that satellite imagery can be used to detect and confirm the North Atlantic right whales at a species level using newly available imaging methods, providing another tool to inform conservation efforts. Using optical satellite imagery with 15 cm resolution, 25 right whales were observed in Cape Cod Bay on April 24, 2021. Species confirmation was possible due to clearly visible callosity patterns indicative of their species within this range. Although the variations in callosity patterns commonly used to identify individuals were too small to be resolved at this image resolution, one whale with large distinctive markings visible on his body was identified at an individual level from satellite imagery alone. Although visual and acoustic survey methods can be combined for monitoring this species in critical habitats, satellite‐based monitoring can be especially helpful to understand whale presence outside the areas monitored with existing visual and acoustic detection methods. [ABSTRACT FROM AUTHOR]

Species' response to rapid climate change can be measured through shifts in timing of recurring biological events, known as phenology. The Gulf of Maine is one of the most rapidly warming regions of the ocean, and thus an ideal system to study phenological and biological responses to climate change. A better understanding of climate‐induced changes in phenology is needed to effectively and adaptively manage human‐wildlife conflicts. Using data from a 20+ year marine mammal observation program, we tested the hypothesis that the phenology of large whale habitat use in Cape Cod Bay has changed and is related to regional‐scale shifts in the thermal onset of spring. We used a multi‐season occupancy model to measure phenological shifts and evaluate trends in the date of peak habitat use for North Atlantic right (Eubalaena glacialis), humpback (Megaptera novaeangliae), and fin (Balaenoptera physalus) whales. The date of peak habitat use shifted by +18.1 days (0.90 days/year) for right whales and +19.1 days (0.96 days/year) for humpback whales. We then evaluated interannual variability in peak habitat use relative to thermal spring transition dates (STD), and hypothesized that right whales, as planktivorous specialist feeders, would exhibit a stronger response to thermal phenology than fin and humpback whales, which are more generalist piscivorous feeders. There was a significant negative effect of western region STD on right whale habitat use, and a significant positive effect of eastern region STD on fin whale habitat use indicating differential responses to spatial seasonal conditions. Protections for threatened and endangered whales have been designed to align with expected phenology of habitat use. Our results show that whales are becoming mismatched with static seasonal management measures through shifts in their timing of habitat use, and they suggest that effective management strategies may need to alter protections as species adapt to climate change. [ABSTRACT FROM AUTHOR]

Aluminium (Al) K‐ and L‐edge X‐ray absorption near‐edge structure (XANES) has been used to examine Al speciation in minerals but it remains unclear whether it is suitable for in situ analyses of Al speciation within plants. The XANES analyses for nine standard compounds and root tissues from soybean (Glycine max), buckwheat (Fagopyrum tataricum), and Arabidopsis (Arabidopsis thaliana) were conducted in situ. It was found that K‐edge XANES is suitable for differentiating between tetrahedral coordination (peak of 1566 eV) and octahedral coordination (peak of 1568 to 1571 eV) Al, but not suitable for separating Al binding to some of the common physiologically relevant compounds in plant tissues. The Al L‐edge XANES, which is more sensitive to changes in the chemical environment, was then examined. However, the poorer detection limit for analyses prevented differentiation of the Al forms in the plant tissues because of their comparatively low Al concentration. Where forms of Al differ markedly, K‐edge analyses are likely to be of value for the examination of Al speciation in plant tissues. However, the apparent inability of Al K‐edge XANES to differentiate between some of the physiologically relevant forms of Al may potentially limit its application within plant tissues, as does the poorer sensitivity at the L‐edge. [ABSTRACT FROM AUTHOR]

Iron (Fe) plays an important role within environmental systems. Synchrotron‐based X‐ray approaches, including X‐ray absorption spectroscopy (XAS), provide powerful tools for in situ analyses of Fe speciation, but beam damage during analysis may alter Fe speciation during its measurement. XAS was used to examine whether experimental conditions affect the analysis of Fe speciation in plant tissues. Even when analyzed in a cryostat at 12 K, it was found that FeIII can rapidly (within 0.5–1 min) photoreduce to FeII, although the magnitude of photoreduction varied depending upon the hydration of the sample, the coordination chemistry of the Fe, as well as other properties. For example, photoreduction of FeIII was considerably higher for aqueous standard compounds than for hydrated plant‐root tissues. The use of freeze‐dried samples in the cryostat (12 K) markedly reduced the magnitude of this FeIII photoreduction, and there was no evidence that the freeze‐drying process itself resulted in experimental artefacts under the current experimental conditions, such as through the oxidation of FeII, although some comparatively small differences were observed when comparing spectra of hydrated and freeze‐dried FeII compounds. The results of this study have demonstrated that FeIII photoreduction can occur during X‐ray analysis, and provides suitable conditions to preserve Fe speciation to minimize the extent of beam damage when analyzing environmental samples. All studies utilizing XAS are encouraged to include a preliminary experiment to determine if beam damage is occurring, and, where appropriate, to take the necessary steps (such as freeze drying) to overcome these issues. [ABSTRACT FROM AUTHOR]

Abstract: Quantifying student engagement with online learning resources on virtual learning environments such as BlackBoard is important in understanding how these technologies enhance the student learning. In the present study, it was examined when, and how often, first‐year students accessed lecture recordings, lecture slides, and lecture notes via BlackBoard, in an introductory natural resource course taken by both on campus students and remote students. The findings demonstrated that lecture recordings were not well utilized by students—although only 58% of on campus students attended face‐to‐face lectures, less than 15% of absent students downloaded the missed lecture. Overall, more students downloaded lecture slides (an average of 63% per week) than notes (38%) or recordings (16%). Indeed, the average student downloaded only 1.1 types of the 3 online resources (recordings, slides, and notes) that were available each week, with 5.7% of students downloading all 3 types of resources, 23% downloading 2 types of resources, 42% downloading only 1 type of resource, and 29% downloading none of the 3 types of resources. Finally, remote students were more likely to download lecture notes and recordings than were on campus students. The information presented here is important in understanding student behaviour and engagement. [ABSTRACT FROM AUTHOR]

Summary: Soil acidity and waterlogging increase manganese (Mn) in leaf tissues to potentially toxic concentrations, an effect reportedly alleviated by increased silicon (Si) and phosphorus (P) supply. Effects of Si and P on Mn toxicity were studied in four plant species using synchrotron‐based micro X‐ray fluorescence (μ‐XRF) and nanoscale secondary ion mass spectrometry (NanoSIMS) to determine Mn distribution in leaf tissues and using synchrotron‐based X‐ray absorption spectroscopy (XAS) to measure Mn speciation in leaves, stems and roots. A concentration of 30 μM Mn in solution was toxic to cowpea and soybean, with 400 μM Mn toxic to sunflower but not white lupin. Unexpectedly, μ‐XRF analysis revealed that 1.4 mM Si in solution decreased Mn toxicity symptoms through increased Mn localization in leaf tissues. NanoSIMS showed Mn and Si co‐localized in the apoplast of soybean epidermal cells and basal cells of sunflower trichomes. Concomitantly, added Si decreased oxidation of Mn(II) to Mn(III) and Mn(IV). An increase from 5 to 50 μM P in solution changed some Mn toxicity symptoms but had little effect on Mn distribution or speciation. We conclude that Si increases localized apoplastic sorption of Mn in cowpea, soybean and sunflower leaves thereby decreasing free Mn2+ accumulation in the apoplast or cytoplasm. [ABSTRACT FROM AUTHOR]

Aluminium (Al) toxicity adversely impacts plant productivity in acid soils by restricting root growth and although several mechanisms are involved the physiological basis of decreased root elongation remains unclear. Understanding the primary mechanisms of Al rhizotoxicity is hindered due to the rapid effects of soluble Al on root growth and the close proximity of many cellular components within the cell wall, plasma membrane, cytosol and nucleus with which Al may react. To overcome some of these difficulties, we report on a novel method for investigating Al interactions with Komagataeibacter xylinus bacterial cellulose (BC)-pectin composites as cell wall analogues. The growth of K. xylinus in the presence of various plant cell wall polysaccharides, such as pectin, has provided a unique in vitro model system with which to investigate the interactions of Al with plant cell wall polysaccharides. The BC-pectin composites reacted in a similar way with Al as do plant cell walls, providing insights into the effects of Al on the mechanical properties of the BC-pectin composites as cell wall analogues. Our findings indicated that there were no significant effects of Al (4-160 μM) on the tensile stress, tensile strain or Young's modulus of the composites. This finding was consistent with cellulose, not pectin, being the major load bearing component in BC-pectin composites, as is also the case in plant cell walls. [ABSTRACT FROM AUTHOR]

Accumulation of arsenic (As) within plant tissues represents a human health risk, but there remains much to learn regarding the speciation of As within plants., We developed synchrotron-based fluorescence-X-ray absorption near-edge spectroscopy (fluorescence- XANES) imaging in hydrated and fresh plant tissues to provide laterally resolved data on the in situ speciation of As in roots of wheat ( Triticum aestivum) and rice ( Oryza sativa) exposed to 2 μM As(V) or As( III)., When exposed to As(V), the As was rapidly reduced to As( III) within the root, with As(V) calculated to be present only in the rhizodermis. However, no uncomplexed As( III) was detected in any root tissues, because of the efficient formation of the As( III)-thiol complex - this As species was calculated to account for all of the As in the cortex and stele. The observation that uncomplexed As( III) was below the detection limit in all root tissues explains why the transport of As to the shoots is low, given that uncomplexed As( III) is the major As species transported within the xylem and phloem., Using fluorescence- XANES imaging, we have provided in situ data showing the accumulation and transformation of As within hydrated and fresh root tissues. [ABSTRACT FROM AUTHOR]

Mechanisms whereby metal cations are toxic to plant roots remain largely unknown. Aluminum, for example, has been recognized as rhizotoxic for approximately 100 yr, but there is no consensus on its mode of action. The authors contend that the primary mechanism of rhizotoxicity of many metal cations is nonspecific and that the magnitude of toxic effects is positively related to the strength with which they bind to hard ligands, especially carboxylate ligands of the cell-wall pectic matrix. Specifically, the authors propose that metal cations have a common toxic mechanism through inhibiting the controlled relaxation of the cell wall as required for elongation. Metal cations such as Al3+ and Hg2+, which bind strongly to hard ligands, are toxic at relatively low concentrations because they bind strongly to the walls of cells in the rhizodermis and outer cortex of the root elongation zone with little movement into the inner tissues. In contrast, metal cations such as Ca2+, Na+, Mn2+, and Zn2+, which bind weakly to hard ligands, bind only weakly to the cell wall and move farther into the root cylinder. Only at high concentrations is their weak binding sufficient to inhibit the relaxation of the cell wall. Finally, different mechanisms would explain why certain metal cations (for example, Tl+, Ag+, Cs+, and Cu2+) are sometimes more toxic than expected through binding to hard ligands. The data presented in the present study demonstrate the importance of strength of binding to hard ligands in influencing a range of important physiological processes within roots through nonspecific mechanisms. Environ Toxicol Chem 2014;33:268-277. © 2013 SETAC [ABSTRACT FROM AUTHOR]

The phytotoxicity of Mn is important globally due to its increased solubility in acid or waterlogged soils. Short-term (≤24 h) solution culture studies with 150 µ M Mn were conducted to investigate the in situ distribution and speciation of Mn in apical tissues of hydrated roots of cowpea [Vigna unguiculata (L.) Walp. cv. Red Caloona] using synchrotron-based techniques. Accumulation of Mn was rapid; exposure to 150 µ M Mn for only 5 min resulting in substantial Mn accumulation in the root cap and associated mucigel. The highest tissue concentrations of Mn were in the root cap, with linear combination fitting of the data suggesting that ≥80% of this Mn(II) was associated with citrate. Interestingly, although the primary site of Mn toxicity is typically the shoots, concentrations of Mn in the stele of the root were not noticeably higher than in the surrounding cortical tissues in the short-term (≤24 h). The data provided here from the in situ analyses of hydrated roots exposed to excess Mn are, to our knowledge, the first of this type to be reported for Mn and provide important information regarding plant responses to high Mn in the rooting environment. [ABSTRACT FROM AUTHOR]

Metal phytotoxicity is important in both environmental and agricultural systems. A solution culture study examined the toxicity of 26 metals to roots of cowpea (Vigna unguiculata (L.) Walp.); new data were collected for 15 metals and published data for 11 metals. Metal toxicity, calculated as causing a 50% reduction in root elongation rate, was determined based on either the measured concentration in the bulk solution (EC50b) or the calculated activity at the outer surface of the plasma membrane (EA50o0 ). The EC50b values ranged from 0.007 mM for Tl to 98,000mM for K, with the order of rhizotoxicity to cowpea, from most to least toxic, beingTl¼Ag>Cu>Hg¼Ni¼Ga¼Ru¼In Sc¼Cd¼Gd¼La¼Co¼Cs¼Pb>Zn¼Al¼H>Mn>Ba¼Sr>Li>Mg>Ca¼ b>Zn¼Al¼H>Mn>Ba¼Sr>Li>Mg>Ca¼ Na>K. The EA50o0 values suggest that the binding of metals to hard ligands is an important, general, nonspecific mechanism of toxicity, a hypothesis supported by the similar toxicity symptoms to roots of cowpea by many metals. However, additional mechanisms, such as strong binding to soft ligands, substantially increase rhizotoxicity of some metals, especially Tl, Ag, and Cs. Besides direct toxic effects, osmotic effects or reduced activity of Ca2þ at the outer surface of the root plasma membrane (and resultant Ca deficiency) may decrease short-term root growth. [ABSTRACT FROM AUTHOR]

Low concentrations of some trace metals markedly reduce root elongation rate and cause ruptures to root rhizodermal and outer cortical cells in the elongation zone. The interactions between the trace metals and plant components responsible for these effects are not well understood but may be linked to changes in water uptake, cell turgor and cell wall extensibility. An experiment was conducted to investigate the effects of Al, La, Cu, Gd, Sc and Ru on the saturated hydraulic conductivity of bacterial cellulose (BC)–pectin composites, used as plant cell wall analogs. Hydraulic conductivity was reduced to ≈30% of the initial flow rate by 39 µ M Al and 0.6 µ M Cu, ≈40% by 4.6 µ M La, 3 µ M Sc and 4.4 µ M Ru and ≈55% by 3.4 µ M Gd. Scanning electron microscopy (SEM) revealed changes in the ultrastructure of the composites. The results suggest that trace metal binding decreases the hydraulic conductivity through changes in pectin porosity. The experiment illustrates the importance of metal interactions with pectin, and the implications of such an interaction in plant metal toxicity and in normal cell wall processes. [ABSTRACT FROM AUTHOR]