Cold Water Temperatures Research Articles

Multi-variable Optimization of HVAC System Using a Genetic Algorithm

Geothermal is a fast-growing alternative heat source for HVAC systems due to higher energy efficiency than conventional heating and cooling systems. However, the initial cost of using a ground source HVAC system is higher compared to an air source system. Studies about system design and operation are necessary to reduce the initial cost and ensure that the ground source heat pump system has high efficiency, resulting in a lower total life-time cost. In this study, a multi-variable evolutionary computation algorithm is proposed for generating optimal parameters for a geothermal source HVAC system. The system consists of borehole heat exchangers (BHE), a water-to-water heat pump and a fan coil unit (FCU) and it was modeled and simulated using MATLAB. The design parameters were calculated by minimizing the energy consumption. These parameters include cold water supply temperature, FCU air flow rate and cooling water flow rate for the underground heat exchangers. In addition, based on an experimental building, a case study was presented. Using this model, the optimal set points were calculated and used as a designed system. Energy consumption of this system was reduced by about 10% compared to the system operated with a fixed supply cold water temperature (7°C). Furthermore, the relationship between system energy consumption and heat pump capacity was expressed. The result showed that the energy consumption increased due to decrease in PLR when the capacity is increased.

Sponge bioerosion accelerated by ocean acidification across species and latitudes?

In many marine biogeographic realms, bioeroding sponges dominate the internal bioerosion of calcareous substrates such as mollusc beds and coral reef framework. They biochemically dissolve part of the carbonate and liberate so-called sponge chips, a process that is expected to be facilitated and accelerated in a more acidic environment inherent to the present global change. The bioerosion capacity of the demosponge Cliona celata Grant, 1826 in subfossil oyster shells was assessed via alkalinity anomaly technique based on 4 days of experimental exposure to three different levels of carbon dioxide partial pressure (pCO2) at ambient temperature in the cold-temperate waters of Helgoland Island, North Sea. The rate of chemical bioerosion at present-day pCO2 was quantified with 0.08–0.1 kg m−2 year−1. Chemical bioerosion was positively correlated with increasing pCO2, with rates more than doubling at carbon dioxide levels predicted for the end of the twenty-first century, clearly confirming that C. celata bioerosion can be expected to be enhanced with progressing ocean acidification (OA). Together with previously published experimental evidence, the present results suggest that OA accelerates sponge bioerosion (1) across latitudes and biogeographic areas, (2) independent of sponge growth form, and (3) for species with or without photosymbionts alike. A general increase in sponge bioerosion with advancing OA can be expected to have a significant impact on global carbonate (re)cycling and may result in widespread negative effects, e.g. on the stability of wild and farmed shellfish populations, as well as calcareous framework builders in tropical and cold-water coral reef ecosystems.

Waterborne Pathogen Detection More than Just “Location, Location, Location…”

The complexity of modern hospitals and increasing proportion of immunologically vulnerable patients make healthcare facility safety a top priority for hospital epidemiologists. Contamination of hospital water systems and point-of-use outlets is a widespread, tenacious problem for which a lasting solution remains elusive. Even when municipal water is maintained within accepted standards of chlorination, structural features of hospital plumbing can lead to contamination of water as it flows distally toward the points of use. Hospitals tend to have large, complex waterworks with low-flow areas that produce stagnation and biofilm formation; hot and cold water temperatures that are not well regulated may be ideal for bacterial growth. Although these conditions occur in other facilities, the susceptibility of hospitalized patients and the presence of invasive devices put them at high risk for infection with organisms that contaminate hospital water. Legionella species are important waterborne pathogens; Enterobacteriaceae, Pseudomonas species, Burkholderia species, Aeromonas species, Stenotrophomonas species, and Acinetobacter species are among the other organisms that are frequently identified

Theoretical investigation of using a direct contact dehumidifier in humidification–dehumidification desalination unit based on an open air cycle

In the present work, a kind of direct contact dehumidification process used in humidification–dehumidification system is introduced instead of using the conventional indirect condensers. In the purposed system, air is dehumidified by spraying cold water into the hot and humid air stream. The freshwater production, efficiency and effects of various parameters including air flow rate, conditions of inlet cold and hot water and velocity and diameter of droplets on the performance of the system are investigated. Results showed that increasing initial velocity and diameter of water droplets decreases water production. Furthermore, it has been demonstrated that increasing the flow rate and temperature of hot water and reducing the flow rate and temperature of cold water will increase freshwater production and the efficiency. It is found that increasing air flow rate has negative effect on production and energy consumption of the system. Direct contact dehumidifier has a good potential in desalination of seawater which can resolve many operational problems of indirect condensers like: corrosion, salt water leakage, and hydraulic pressure drop.

Movements of Arctic and northwest Atlantic Greenland sharks (Somniosus microcephalus) monitored with archival satellite pop-up tags suggest long-range migrations

Greenland sharks (Somniosus microcephalus) are large carnivorous sharks that appear to be widely distributed in Arctic seas and in deep, cold temperate waters. In order to examine their movement patterns, diving behaviour and temperature preferences, pop-up archival transmitting tags (PATs) were deployed on 15 Greenland sharks up to 5.1m in length, both in the Canadian Arctic and in the northwest Atlantic off the eastern coast of Canada. Tags remained on the sharks up to 11 months (mean of 149 days, including four tags which came off prematurely) before popping off. All sharks travelled a minimum of 315km, and some as much as 1615km, at depths of up to 1816m. All tagged Greenland sharks in the Arctic exited the relatively shallow, coastal waters of Cumberland Sound before sexual maturation, presumably moving to spend their adult lives in the deeper waters of the Davis Strait to the north. All the presumably mature Greenland sharks tagged in the NW Atlantic moved up to 1000km off the continental shelf over abyssal waters to the south. There was extensive evidence of pelagic swimming in both regions, but diel vertical excursions into the water column were not observed. The mean temperature of 2.7°C recorded in the Arctic sharks was much less than the 7.9°C mean temperature observed in the Atlantic sharks, where a maximum temperature of 17.2°C was recorded. Our results indicate that Greenland sharks can inhabit very deep waters, and they can inhabit very cold waters, but they do not necessarily have to inhabit deep, cold waters. It is possible that Greenland sharks migrate offshore over very deep waters to mate and/or give birth.

The effects of an abnormal decrease in temperature on the Eastern Pacific reef-building coral Pocillopora verrucosa

Coral bleaching events are associated with abnormal increases in temperature, such as those produced during El Nino. Recently, a breakdown in the coral–dinoflagellate (genus Symbiodinium) endosymbiosis has been documented in corals exposed to anomalously cold-water temperatures associated with La Nina events. Given the ecological significance of such events, as well as the threat of global climate change, surprisingly little is known about the physiological response of corals to cold stress. This study evaluated some physiological effects of continuous temperature decline in colonies of the eastern Pacific reef-building coral Pocillopora verrucosa. Twenty days of incubation at 18.5–19.0 °C resulted in a substantial decrease in holobiont lipid and Chla content, as well as an increase in Symbiodinium density. These observations suggest a combination of symbiont acclimation due to the temperature decline and reallocation of carbon toward algal growth as opposed to translocation to the host coral. With a decreased availability of symbiont-derived carbon, the coral likely catabolized storage lipids in order to survive the stress event. Despite this stress and some tissue necrosis, no mortality was noted and corals recovered quickly when returned to the ambient temperature. As these results are in marked contrast to similar studies investigating elevated temperature on this coral from this same location, Pocillopora in the Mexican Central Pacific may be more prone to long-term damage and mortality during periods of ocean warming as opposed to ocean cooling.

Occurrence of the Chilean devil ray Mobula tarapacana (Elasmobranchii: Batoidea: Myliobatiformes) in the Sea of Okhotsk: first record from cold temperate waters

The northernmost record for Chilean devil ray Mobula tarapacana, a circumglobal species that occurs in tropical, subtropical and limited warm temperate waters, is described. An adult female was caught incidentally in the Sea of Okhotsk on 17 September 2011. This specimen is the first confirmed occurrence of devil rays Mobula spp. in cold temperate waters.

Environmental Influences on the Abundance and Sexual Composition of White Sharks Carcharodon carcharias in Gansbaai, South Africa

The seasonal occurrence of white sharks visiting Gansbaai, South Africa was investigated from 2007 to 2011 using sightings from white shark cage diving boats. Generalized linear models were used to investigate the number of great white sharks sighted per trip in relation to sex, month, sea surface temperature and Multivariate El Niño/Southern Oscillation (ENSO) Indices (MEI). Water conditions are more variable in summer than winter due to wind-driven cold water upwelling and thermocline displacement, culminating in colder water temperatures, and shark sightings of both sexes were higher during the autumn and winter months (March–August). MEI, an index to quantify the strength of Southern Oscillation, differed in its effect on the recorded numbers of male and female white sharks, with highly significant interannual trends. This data suggests that water temperature and climatic phenomena influence the abundance of white sharks at this coastal site. In this study, more females were seen in Gansbaai overall in warmer water/positive MEI years. Conversely, the opposite trend was observed for males. In cool water years (2010 to 2011) sightings of male sharks were significantly higher than in previous years. The influence of environmental factors on the physiology of sharks in terms of their size and sex is discussed. The findings of this study could contribute to bather safety programmes because the incorporation of environmental parameters into predictive models may help identify times and localities of higher risk to bathers and help mitigate human-white shark interactions.

Energy audit and air-conditioning system renovation analysis on office buildings using air-source heat pump in Shanghai

In the past, the building energy consumption was surveyed without distinction of air-conditioning system types, which caused large dispersal of the energy consumption of the same building type. To study energy consumption of office buildings using air-source heat pump, six office buildings using air-source heat pump in Shanghai were investigated through energy audit and field test. The energy use intensity (EUI) per annum ranged from 102 to 139 kWh/m2, with an average value of 126 kWh/m2. The EUI range of office buildings using air-source heat pump is much smaller than the EUI of office buildings according to the literature. Based on field test of the air-conditioning (A/C) system, it was found that the present main problem of A/C system included insufficient refrigeration capacity of A/C system, low A/C system energy efficiency, and small cold water temperature difference. Countermeasures were brought forward to solve the problems, including ① retrofitting part of the present air-source heat pumps to water-cooled cold water air-conditioners, ② retrofitting present air-source heat pumps into new air-source heat pumps, and ④ pump variable frequency renovation. The A/C load is estimated by Bin method. According to the case study in this paper, the pay back period are about two years for the first measure, five to seven years for the second measure, and 0.65–2 years for the third measure. Practical application: Generally, the energy consumption survey gives a wide range of data. To some extent, it is caused by the survey method which does not take the air-conditioning type into consideration. The work stresses on the energy consumption of office buildings using air-source heat pump. The result showed that the energy consumption was in a relatively small range, which will be more meaningful to industry. Energy saving measures concerning air-conditioning system is studied on the basis of the survey.

Performance Study and Comparison of Three Types of Film Fill Packings in Bisotoun Power Plant of Kermanshah Province in Iran Using Merkel Model

This study deals with calculation and comparison of performance parameters of three types of horizontal, vertical and mixed corrugated film fill packing, to their actual values in cooling tower of the Bisotoun power plant. Through this, performances of cooling packing are compared with each other. Also utilization of the most appropriate cooling tower in Bisotoun power plant has been investigated. In order to rich the above mentioned goals, added to describing performance of physical mechanisms in wet mechanical counter current cooling towers and Merkel’s thermal theory, thermal properties of the pre-mentioned cooling packings are presented also, moreover performance parameters of the three packing are calculated and compared, then the appropriate conclusion is made. The results show that among the three packings, because of having appropriate characteristics like higher surface to volume ratio and mass transport coefficient and so on, the mixed corrugated packing has had the best performance in comparison with the other two packings and can perform acceptable in Bisotoun power plant. As, the Values of the cold water temperatures, the temperature difference between cold water and wet point temperature of the ambient and the coolness range the mixed corrugated packing is fully consistent with those gathered from the power plant’s data. However, values of these parameters show considerable difference in two other packing with their counterparts in Bisotoun power plant, the water flow rate to air flow rate ratio in the mentioned packing shows a tiny difference with the actual value in the power plant which is 2.15 (1.4% increase). If this packing was used the amount of air used to cool down the water in the cooling tower which is prepared by each fan would be 521 m³/secs, which defers 5.4 % with that of Bisotoun, that is 551 m³/sec.

Eared grebe diet on Great Salt Lake, Utah, and competition with the commercial harvest of brine shrimp cysts

AbstractInteractions between wildlife and commercial harvest industries need to be understood to manage resources for all users. About 1.5 million eared grebes (Podiceps nigricollis), half the North American population, stage on Utah's Great Salt Lake (GSL) each fall. A $56 million commercial harvest industry also operates during fall when the harvest of brine shrimp (Artemia franciscana) cysts occurs. Eared grebes and commercial harvest both utilize brine shrimp cysts creating a potentially adverse relationship. We assessed the diet of eared grebes to determine the extent to which they are dependent on brine shrimp and their cysts. We collected individual birds to measure diets and examine changes in body condition of staging eared grebes. Cysts were consumed by 40% of collected eared grebes and made up >75% of aggregate biomass of stomach samples. Despite the high occurrence of cysts in stomach samples, cysts were not the primary food item of eared grebes. Cysts were held in the stomach for longer periods by feather mass, so esophagus samples were a better indicator of diet. Adult brine shrimp were the primary food collected from the esophagus from October until December. After cold water temperatures caused a die‐off of adult brine shrimp, cysts became more prevalent in the diet of eared grebes. Concomitantly, eared grebe body weights decreased as their diet shifted to brine shrimp cysts. Current monitoring and management of commercial harvest are sufficient to maintain yearly populations of adult brine shrimp to sustain eared grebes populations. © 2013 The Wildlife Society.

Thermal controls of Yellowstone cutthroat trout and invasive fishes under climate change

We combine large observed data sets and dynamically downscaled climate data to explore historic and future (2050-2069) stream temperature changes over the topographically diverse Greater Yellowstone Ecosystem (elevation range = 824-4017 m). We link future stream temperatures with fish growth models to investigate how changing thermal regimes could influence the future distribution and persistence of native Yellowstone cutthroat trout (YCT) and competing invasive species. We find that stream temperatures during the recent decade (2000-2009) surpass the anomalously warm period of the 1930s. Climate simulations indicate air temperatures will warm by 1 °C to >3 °C over the Greater Yellowstone by mid-21st century, resulting in concomitant increases in 2050-2069 peak stream temperatures and protracted periods of warming from May to September (MJJAS). Projected changes in thermal regimes during the MJJAS growing season modify the trajectories of daily growth rates at all elevations with pronounced growth during early and late summer. For high-elevation populations, we find considerable increases in fish body mass attributable both to warming of cold-water temperatures and to extended growing seasons. During peak July to August warming, mid-21st century temperatures will cause periods of increased thermal stress, rendering some low-elevation streams less suitable for YCT. The majority (80%) of sites currently inhabited by YCT, however, display minimal loss (<10%) or positive changes in total body mass by midcentury; we attribute this response to the fact that many low-elevation populations of YCT have already been extirpated by historical changes in land use and invasions of non-native species. Our results further suggest that benefits to YCT populations due to warmer stream temperatures at currently cold sites could be offset by the interspecific effects of corresponding growth of sympatric, non-native species, underscoring the importance of developing climate adaptation strategies that reduce limiting factors such as non-native species and habitat degradation.

Identification of Winter Flounder (Pseudopleuronectes americanus) Estuarine Spawning Habitat and Factors Influencing Egg and Larval Distributions

A long-term (2002–2011), spatially robust, ichthyoplankton sampling program conducted in the New York/New Jersey Harbor produced 3,033 epibenthic samples from which the relationships between winter flounder egg and larval distributions and environmental parameters were examined. Variations in water temperature, sediment characteristics, and tidal phase were all significantly associated with egg distributions. Inferences about spawning habitats were based on the presence of early-stage eggs (ES1 and ES2). In the Lower Bay (LB), these habitats were primarily non-channel and characterized by more sandy substrates, averaging 96.5 % sand, 2.3 % silt/clay, 0.2 % total organic carbon (TOC), and shallower water (average depths of 5.3 m) compared to LB non-channel stations without ES1 and ES2 eggs (50.2 % sand, 42.0 % silt/clay, 2.1 % TOC, and 7.9 m depths). Occurrences of all stages of eggs in channels were associated with strong tides and severe cold winter water temperatures. These conditions increase the probability of egg transport from shallow spawning sites through increased vertical mixing (strong tides) and delayed development that prolongs the risk of displacement (cold temperatures). Yolk-sac (YS) and Stage-2 larvae were smaller in 2010 when spring water temperatures were highest. Overall, YS larval size decreased with warmer winters (cumulative degree-days for the month preceding peak YS larval collections, r2 = 0.82, p < 0.05). In all years, YS larvae collected in LB were smaller and Stage-3 larvae collected in channels were larger and possibly older than those from non-channel habitat. Because estuarine winter flounder populations are highly localized, adverse effects experienced during egg and larval stages are likely to propagate resulting in detrimental consequences for the year class in the natal estuary.

Sediment transport processes at the head of Halibut Canyon, eastern Canada margin: An interplay between internal tides and dense shelf-water cascading

To investigate the processes by which sediment is transported through a submarine canyon incised in a glaciated margin, the bottom boundary layer quadrapod RALPH was deployed at 276-m depth in the West Halibut Canyon (off Newfoundland) during winter 2008–2009. Two main sediment transport processes were identified throughout the deployment. Firstly, periodic increases of near-bottom suspended-sediment concentrations (SSC) were recorded associated with the up-canyon propagation of the semidiurnal internal tidal bore along the canyon axis, carrying fine sediment particles resuspended from deeper canyon regions. The recorded SSC peaks, lasting less than 1 h, were observed sporadically and were linked to bottom intensified up-canyon flows (~ 40 cm s− 1) concomitant with sharp drops in temperature. Secondly, sediment transport was also observed during events of intensified down-canyon current velocities that occurred during periods of sustained heat loss from surface waters, but were not associated with large storm waves. High-resolution velocity profiles throughout the water column during these events revealed that the highest current speeds (~ 1 m s− 1) were centered several meters above the sea floor and corresponded to the region of maximum velocities of a gravity flow. Such flows had associated low SSC and cold water temperatures and are interpreted as dense shelf water cascading events channelized along the canyon axis. Sediment transport during these events was largely restricted to bedload and saltation, producing winnowing of sands and fine sediments around larger gravel particles. Analysis of historical hydrographic data suggests that such gravity flows are not related to the formation of coastal dense waters advected towards the outer shelf that reached the canyon head. Rather, the dense shelf waters appear to be generated around the outer shelf, where convection during winter is able to reach the sea floor and generate a pool of near-bottom dense water that cascades into the canyon during one or two tidal cycles. A similar transport mechanism is likely to occur in other submarine canyons along the eastern Canadian margin, as well in other canyoned margins where winter convection can reach the shelf-edge.

Underlying causes of yield spatial variability and potential for precision management in rice systems

Our current understanding of the mechanisms driving spatiotemporal yield variability in rice systems is insufficient for effective management at the sub-field scale. The overall objective of this study was to evaluate the potential of precision management for rice production. The spatiotemporal properties of multiyear yield monitor data from four rice fields, representing varying soil types and locations within the primary rice growing region in California, were quantified and characterized. The role of water management, land-leveling, and the spatial distribution of soil properties in driving yield heterogeneity was explored. Mean yield and coefficient of variation at the sampling points within each field ranged from 9.2 to 12.1 Mg ha−1 and from 7.1 to 14.5 %, respectively. Using a k-means clustering and randomization method, temporally stable yield patterns were identified in three of the four fields. Redistribution of dissolved organic carbon, nitrogen, potassium and salts by lateral flood water movement was observed across all fields, but was only related to yield variability via exacerbating areas with high soil salinity. The effects of cold water temperature and land-leveling on yield variability were not observed. Soil electrical conductivity and/or plant available phosphorus were identified as the underlying causes of the within-field yield patterns using classification and regression trees. Our results demonstrate that while the high temporal yield variability in some rice fields does not permit precision management, in other fields exhibiting stable yield patterns with identifiable causes, precision management and modified water management may improve the profitability and resource-use efficiency of rice production systems.

A re-evaluation of morphological characters of the invasive ascidian Corella eumyota reveals two different species at the tip of South America and in the South Shetland Islands, Antarctica

The native solitary ascidian Corella eumyota Traustedt, 1882) is commonly found in the Southern Hemisphere in the cold-temperate waters of the Subantarctic and Antarctic regions. Its recent spread into the Northern Hemisphere throughout the NE Atlantic gave the species the status of invasive. Together with its widespread distribution, reports on its wide variability (several distinct morphological characters, genetic discontinuities and also possible misidentifications) cast doubt on the taxonomic status of different populations of this species. This work, based on the observation, quantification and analysis of specific morphological characters in specimens collected at five different localities of South America and Antarctica, strongly indicates that there are two different species: C. eumyota from South America and Corella antarctica Sluiter, 1905) from Antarctica, which has been till now considered a junior synonym of the former. The species clearly differ in the arrangement of the gonadal ducts, the size of the larvae and the shape of the anus, among other characters. Morphological variation displays a defined, discrete grouping supporting a clear differentiation into two species. This result shows the need for careful inspection of specimens to avoid wrong interpretations in a context of changes of marine biota due to biological invasions.

Passive Integrated Transponder (PIT) Tracking versus Snorkeling: Quantification of Fright Bias and Comparison of Techniques in Habitat Use Studies

AbstractQuantitative assessment of day and night fright bias (i.e., flight response) of Atlantic Salmon Salmo salar parr during passive integrated transponder (PIT) tracking surveys was carried out during summer (water temperature, 18–22°C) and autumn (water temperature, &lt;3°C). In addition, PIT‐tracking and snorkeling survey methods were compared to assess whether the two methods result in similar habitat use data for Atlantic Salmon parr at the same study site. During summer fright bias surveys, 0–15% of parr displayed a flight response to PIT‐tracking techniques in the riffle–run–pool habitat types commonly used by Atlantic Salmon parr; 24–25% displayed a flight response in relatively unused, shallow, calm water habitats. No flight responses were observed in autumn surveys with colder water temperatures in any habitat type. Larger numbers of salmon parr were observed using PIT tracking regardless of stream discharge. Furthermore, significant differences in habitat use frequency curves between these two methods were observed due largely to higher Atlantic Salmon parr abundances being detected by PIT tracking in shallow water depths at lower discharges and the ability to detect inactive salmon parr hiding within the substrate. PIT tracking was found to be a valid method for habitat assessment and provides more reliable habitat use data than traditional snorkeling methods in small streams.

Experimental investigation of the performance of a triple concentric pipe heat exchanger

The performance of a triple concentric pipe heat exchanger is studied experimentally under steady state conditions for two different flow arrangements, called N–H–C and C–H–N, and for insulated as well as non-insulated conditions of the heat exchanger. The three fluids being considered are hot water, cold water and the normal tap water. Under N–H–C arrangement, normal water flows in the innermost pipe, hot water flows in the inner annulus, and the cold water flows in the outer annulus. All fluids flow parallel to each other. Cold and normal water are interchanged in the C–H–N arrangement keeping hot water flow unchanged. The results are presented in the form of the temperature variations of the three fluids along the length of the heat exchanger for their different flow rates. It is found that the temperature variation along the length of pipe differs substantially for the two arrangements. Temperature of cold water increases rapidly in the non-insulated condition of N–H–C arrangement. Cross over points are found in N–H–C arrangement for higher volume flow rates of the three fluids.

Thermal acclimation in rainbow smelt, Osmerus mordax, leads to faster myotomal muscle contractile properties and improved swimming performance

SummaryRainbow smelt (Osmerus mordax) display an impressive ability to acclimate to very cold water temperatures. These fish express both anti-freeze proteins and glycerol in their plasma, liver, muscle and other tissues to avoid freezing at sub-zero temperatures. Maintenance of glycerol levels requires active feeding in very cold water. To understand how these fish can maintain activity at cold temperatures, we explored thermal acclimation by the myotomal muscle of smelt exposed to cold water. We hypothesized that cold-acclimated fish would show enhanced swimming ability due to shifts in muscle contractile properties. We also predicted that shifts in swimming performance would be associated with changes in the expression patterns of muscle proteins such as parvalbumin (PV) and myosin heavy chain (MyHC). Swimming studies show significantly faster swimming by smelt acclimated to 5°C compared to fish acclimated to 20°C when tested at a common test temperature of 10°C. The cold-acclimated fish also had faster muscle contractile properties, such as a maximum shortening velocity (Vmax) almost double that of warm-acclimated fish at the same test temperature. Cold-acclimation is associated with a modest increase in PV levels in the swimming muscle. Fluorescence microscopy using anti-MyHC antibodies suggests that MyHC expression in the myotomal muscle may shift in response to exposure to cold water. The complex set of physiological responses that comprise cold-acclimation in smelt includes modifications in muscle function to permit active locomotion in cold water.

Integrative modelling of animal movement: incorporatingin situhabitat and behavioural information for a migratory marine predator

A fundamental goal in animal ecology is to quantify how environmental (and other) factors influence individual movement, as this is key to understanding responsiveness of populations to future change. However, quantitative interpretation of individual-based telemetry data is hampered by the complexity of, and error within, these multi-dimensional data. Here, we present an integrative hierarchical Bayesian state-space modelling approach where, for the first time, the mechanistic process model for the movement state of animals directly incorporates both environmental and other behavioural information, and observation and process model parameters are estimated within a single model. When applied to a migratory marine predator, the southern elephant seal (Mirounga leonina), we find the switch from directed to resident movement state was associated with colder water temperatures, relatively short dive bottom time and rapid descent rates. The approach presented here can have widespread utility for quantifying movement-behaviour (diving or other)-environment relationships across species and systems.