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Understanding how organisms respond to environmental change is one of the most pressing grand challenges of organismal biology. In the vast oceans that cover 71% of Earth’s surface, remote sensing technologies have created unprecedented opportunities to create new knowledge and deliver integrated understandings of marine organism-environment interactions via long-term monitoring. Using historic whaling records and >15 years of satellite-derived data, we show that movement parameters associated with long-distance humpback whale migrations, including utilization of a south-southeast directed migratory corridor, migration path straightness, direction, timing and velocity, have not significantly changed during a period of dynamic oceanographic and geomagnetic conditions. These findings reveal an apparent paradox: humpback whale migrations do not change in a changing ocean. Geophysical analyses of the same humpback whale movements demonstrate that these whales maintained prolonged migratory fidelity to a limited suite of spatiotemporal trajectories through gravitational coordinates, raising the possibility that migratory decisions are relatively insensitive to changing oceanographic and geomagnetic conditions. Our findings highlight the importance of filling the knowledge-gaps that currently limit our ability to understand and anticipate organismal responses to rapidly changing Earth system conditions.

Nitrate pollution is a global issue threatening the health and function of many lowland freshwater ecosystems. Quantifying nitrate loads and instream attenuation associated with land use is a critical requirement for improving freshwater management. One often overlooked nitrate source in catchments is invasive N-fixing trees such as Ulex europaeus (European gorse). This study compared nitrate concentrations in conjunction with stable isotope analyses (nitrate δ¹⁵N and δ¹⁸O) to investigate the effects of catchment gorse cover on stream nitrate export relative to three other land uses. These were regenerating native forest, low-intensity (dry-stock) and high-intensity (dairying) agriculture. We tested two hypotheses: (1) gorse is a regionally significant nitrate source; (2) instream nitrate attenuation is land-use dependent. The study was conducted in 24 reaches across six small, mixed land-use coastal catchments located on Banks Peninsula, New Zealand. Our results demonstrated that gorse-dominated stream reaches had significantly higher nitrate concentrations than all other land uses. Within the gorse-dominated reaches, nitrate concentration was significantly correlated with upstream catchment gorse cover. Furthermore, nitrate oxygen and nitrogen stable isotope compositions demonstrated that elevated nitrate concentrations in gorse streams were associated with decomposition of dead gorse foliage. The isotope data revealed sub-catchment-scale land-use-specific patterns of nitrate attenuation within streams. All three anthropogenic land uses (gorse, dry stock and dairy) showed distinctly different N-cycling from native-forested reaches where nitrate was efficiently cycled with evidence for highly localised nitrification. Stable isotope data demonstrated that overall nitrate attenuation became less efficient with higher nitrate loads. Our research demonstrates the significant impact N-fixing plants have on nitrate concentrations and instream attenuation. Quantifying the effects of N-fixing plants on water quality is an important step in achieving globally significant goals of sustaining ecosystem health and (sub) catchmentscale nutrient management.

Measuring and monitoring the behavior and biomedical condition of free-ranging whales remains a fundamental challenge in cetacean science and conservation. Advances in unoccupied aerial systems (UAS) and infrared thermography (IRT) create unprecedented opportunities to fill these knowledge gaps and advance our understanding of how cetaceans interact with the environment. Here, we show that non-invasive UAS-IRT systems, deployed from shore-based positions in a humpback whale (Megaptera novaeangliae) calving ground, can be used to document rarely observed whale behaviors and quantify biomedical vital signs. Our findings demonstrate: 1) prolonged (>3 h) logging behavior by a mother-calf pair located ~550 m offshore; 2) that the calf’s respiration rate (~3 breaths per minute) was 6 times higher than its mother’s (~0.5 breaths per minute); 3) that the calf’s blowholes were ~1.55° C warmer than adjacent ocean water and that the mother’s blowholes were ~2.16° C warmer than adjacent ocean water; 4) that the mother’s dorsal fin included four infrared hot-spots, each separated by ~20 cm in horizontal distance, that ranged between 1° C and 2° C warmer than adjacent ocean water; 5) a significant (p<<0.05; wavelet analysis) temporal cyclicity in the hottest of the mother’s dorsal fin hot-spots consistent with cardiovascular blood flow pumped at an apneic heart rate of 9.3 beats per minute. Wider deployment and development of UAS-IRT technologies should help to both overcome current challenges, including cost and data processing, and provide unique perspectives and data that will inform our understanding of whale behavior and biomedical condition in rapidly changing marine systems.

Frost formation occurs on evaporator fin surfaces of heat pumps in heating mode when the surface temperature is below the frost point and the moisture content is sufficiently high. This frost on fin surfaces can significantly degrade the performance of air-source heat pump systems. This paper studies a novel mechanical defrosting approach for heat exchanger fins through integrating shape morphing cells in the fins. The shape morphing defrosting strategy relies on embedded structures with negative stiffness characteristics. These structures can undergo snap-through and suddenly release energy upon actuation. The snap-through induces out of plane displacements and vibrations to break and shed the accumulated frost. We modify flat fin geometry and introduce bistability in the heat exchanger fins. The bistable characteristics of modified copper-coated aluminum and weld steel fins are experimentally investigated. The defrosting performance of the fins is studied by forming glazelike ice using thermoelectric devices. The energy needed for mechanical and thermal defrosting strategy is experimentally found and a direct comparison is carried out between the strategies.

The Hutton's shearwater Puffinus huttoni is an endangered seabird endemic to Kaikōura, New Zealand, but the spatial and temporal aspects of its at‐sea foraging behavior are not well known. To identify foraging areas and estimate trip durations, we deployed Global Positioning Systems (GPS) devices and Time‐Depth Recorders (TDR) on 26 adult Hutton's shearwaters during the chick‐rearing period in 2017 and 2018. We found Hutton's shearwaters traveled much further from their breeding grounds at Kaikōura than previously considered, with most individuals foraging in coastal and oceanic areas 125–365 km south and near Banks Peninsula. Trip durations varied from 1 to 15 days (mean = 5 days), and total track lengths varied from 264 to 2,157 km (mean = 1092.9 km). Although some diving occurred in near‐shore waters near the breeding colony, most foraging was concentrated in four regions south of Kaikōura. Dive durations averaged 23.2 s (range 8.1 to 71.3 s) and dive depths averaged 7.1 m (range 1.5 to 30 m). Foraging locations had higher chlorophyll a levels and shallower water depths than nonforaging locations. Birds did not feed at night, but tended to raft in areas with deeper water than foraging locations. Mapping the spatial and temporal distribution of Hutton's shearwaters at sea will be fundamental to their conservation, as it can reveal potential areas of overlap with fisheries and other industrial users of the marine environment. To identify the at‐sea behavior of Hutton's shearwater, a threatened New Zealand seabird, we deployed Global Positioning System devices and Time‐Depth Recorders on 26 birds in 2017 and 2018. We found Hutton's shearwaters traveled much further from their breeding grounds than previously considered, with trip durations averaging 5 days and over 1,000 km in length. Birds dived to depths of 30 m and foraged in locations characterized by higher chlorophyll a levels and shallower water depths. Mapping the distribution of Hutton's shearwaters at sea can reveal potential areas of conflict with fisheries and other users of the marine environment.

The French Creek Granite, New Zealand, is an alkaline intrusion with enrichment in rare earth elements (REE). Petrography and whole-rock geochemical signatures demonstrate that the c. 82–84-Ma French Creek Granite is a composite granitoid, dominated by a ferroan, weakly peraluminous biotite alkali feldspar granite to syenogranite, with subordinate quartz-alkali feldspar (QAF) syenite. Maximum total REE + Y contents are higher in the granite and felsic dikes relative to the marginal QAF syenite, cogenetic mafic Hohonu Dike Swarm, and pegmatites. Our findings suggest that REE and high-field-strength element enrichment in the unaltered French Creek Granite is a function of partial melting from an enriched HIMU-like lithospheric mantle source, minor crustal assimilation, and extensive magmatic differentiation. Primary (magmatic) REE enrichment is defined by the occurrence of allanite, zircon, apatite, fergusonite, monazite, perrierite, and loparite, which are commonly associated with interstitial biotite. French Creek Granite samples from a phyllic-sericitic alteration zone in the Eastern Hohonu River are strongly elevated in REE relative to unaltered French Creek Granite, indicating remobilization and secondary REE enrichment by hydrothermal fluids. The REE are hosted in bastnäsite group minerals, monazite, xenotime, and zircon. Quartz protuberances, dilatational microfractures, and dike emplacement indicate that this alteration is structurally controlled. The δ13C and δ18O values of secondary carbonate veinlets are consistent with mixed low-temperature (~ 250–260 °C) magmatic hydrothermal fluids containing mantle-derived carbon. These fluids were likely part of a late-stage porphyry-type system operating during the same mantle degassing and extensional episode that was associated with the emplacement of the French Creek Granite and lamprophyric dikes of the Hohonu Dike Swarm, and initial Tasman Sea spreading. Results from this study provide an important insight into the complex processes responsible for REE enrichment in alkaline igneous systems.

The growing applications of variable-speed and tandem compressors, coupled with emerging refrigerant-oil combinations, can lead to higher levels of oil retention in vapor-compression systems, especially at lower refrigerant mass flow rates. To develop better designs and mitigation strategies, it is important to have methods for accurately measuring oil circulation ratio (OCR). High levels of OCR reduce the efficiency of heat exchangers (i.e., evaporators and condensers) and cause the compressor's oil level to reduce, which may ultimately affect its efficiency and life span. However, measuring OCR within a vapor-compression cycle is challenging due to various factors, such as the phase change of the working fluid at different locations, miscibility between the oil and refrigerant, and varying flow regimes. The objective of this study was to develop a noninvasive, in-situ method to measure OCR in real time, which involves minimal human intervention. An OCR measurement method is presented using an oil separator and a level measurement sensor. The approach has been validated with two different methods, one of which is an ASHRAE standard. The relative differences in the OCR measurement between the liquid level probe and ASHRAE standard methods are less than 12%.

Stable isotope analysis of feathers can provide an indirect method to investigate the diet and foraging locations of birds during the time the feathers were growing. We used the isotopic composition of experimentally-induced feathers to investigate the foraging locations of the Hutton’s shearwater (Puffinus huttoni), an endangered seabird that is a breeding endemic to the Kaikoura region of New Zealand. The isotopic composition of feathers was first compared with potential prey items collected from the near-shore marine environment near the breeding colony. By applying trophic fractionation factors (2–4 ‰ increase in δ¹⁵N for every 1 ‰ increase in δ¹³ C) and comparing the isotopic composition of the induced tail feathers and sampled prey items, we found that feather isotopic compositions were not consistent with a diet based on feeding locally. Both the δ¹³C and δ¹⁵N from zooplankton and fish collected within 8 km of Kaikōura were significantly different than the isotopic composition of induced feathers and were outside of the range expected for consumed local prey items. Instead, we found the isotopic composition of Hutton’s shearwater feathers was more consistent with feeding on potential prey items in the seas north-east and around Banks Peninsula, an area c. 100 km south of the breeding colony and where they had been tracked previously. Stable isotope analysis can provide insight into the foraging behaviour of birds at sea and demonstrates the importance of isotopic research in pinpointing foraging locations in seabirds with large geographic ranges.

The conservation and protection of marine megafauna require robust knowledge of where and when animals are located. Yet, our ability to predict animal distributions in space and time remains limited due to difficulties associated with studying elusive animals with large home ranges. The widespread deployment of satellite telemetry technology creates unprecedented opportunities to remotely monitor animal movements and to analyse the spatial and temporal trajectories of these movements from a variety of geophysical perspectives. Reproducible patterns in movement trajectories can help elucidate the potential mechanisms by which marine megafauna navigate across vast expanses of open-ocean. Here, we present an empirical analysis of humpback whale (Megaptera novaeangliae), great white shark (Carcharodon carcharias) and northern elephant seal (Mirounga angustirostris) satellite telemetry-derived route fidelity movements in magnetic and gravitational coordinates. Our analyses demonstrate that: 1) humpback whales, great white sharks and northern elephant seals are capable of performing route fidelity movements across millions of square kilometers of open ocean with a spatial accuracy of better than 150 km despite temporal separations as long as 7 years between individual movements; 2) route fidelity movements include significant (p<0.05) periodicities that are comparable in duration to the lunar cycles and semi-cycles; 3) latitude and bedrock-dependent gravitational cues are stronger predictors of route fidelity movements than spherical magnetic coordinate cues when analysed with respect to the temporally dependent moon illumination cycle. We further show that both route fidelity and non-route fidelity movement trajectories, for all three species, describe overlapping in-phase or antiphase sinusoids when individual movements are normalised to the gravitational acceleration present at migratory departure sites. Although these empirical results provide an inductive basis for the development of testable hypotheses and future research questions, they cannot be taken as evidence for causal relations between marine megafauna movement decisions and geophysical cues. Experiments on model organisms with known sensitivities to gravity and magnetism, complemented by further empirical observation of free-ranging animals, are required to fully explore how animals use discrete, or potentially integrated, geophysical cues for orientation and navigation purposes.

Despite the increasing interest in organic Rankine cycle (ORC) systems and the large number of cycle models proposed in the literature, charge-based ORC models are still almost absent. In this paper, a detailed overall ORC simulation model is presented based on two solution strategies: condenser subcooling and total working fluid charge of the system. The latter allows the subcooling level to be predicted rather than specified as an input. The overall cycle model is composed of independent models for pump, expander, line sets, liquid receiver and heat exchangers. Empirical and semi-empirical models are adopted for the pump and expander, respectively. A generalized steady-state moving boundary method is used to model the heat exchangers. The line sets and liquid receiver are used to better estimate the total charge of the system and pressure drops. Finally, the individual components are connected to form a cycle model in an object-oriented fashion. The solution algorithm includes a preconditioner to guess reasonable values for the evaporating and condensing temperatures and a main cycle solver loop which drives to zero a set of residuals to ensure the convergence of the solution. The model has been developed in the Python programming language. A thorough validation is then carried out against experimental data obtained from two test setups having different nominal size, working fluids and individual components: (i) a regenerative ORC with a 5 kW scroll expander and an oil flooding loop; (ii) a regenerative ORC with a 11 kW single-screw expander. The computer code is made available through open-source dissemination.