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Author |
G. J. Sutton, C. A. Bost, A. Z. Kouzani, S. D. Adams, K. Mitchell, J. P. Y. Arnould |
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Title |
Fine-scale foraging effort and efficiency of Macaroni penguins is influenced by prey type, patch density and temporal dynamics |
Type |
Journal |
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Year |
2021 |
Publication |
Marine Biology |
Abbreviated Journal |
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Volume |
168 |
Issue |
1 |
Pages |
3 |
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Abstract |
Difficulties quantifying in situ prey patch quality have limited our understanding of how marine predators respond to variation within and between patches, and throughout their foraging range. In the present study, animal-borne video, GPS, accelerometer and dive behaviour data loggers were used to investigate the fine-scale foraging behaviour of Macaroni penguins (Eudyptes chrysolophus) in response to prey type, patch density and temporal variation in diving behaviour. Individuals mainly dived during the day and utilised two strategies, targeting different prey types. Subantarctic krill (Euphausia vallentini) were consumed during deep dives, while small soft-bodied fish were captured on shallow dives or during the ascent phase of deep dives. Despite breeding in large colonies individuals seemed to be solitary foragers and did not engage with conspecifics in coordinated behaviour as seen in other group foraging penguin species. This potentially reflects the high abundance and low manoeuvrability of krill. Video data were used to validate prey capture signals in accelerometer data and a Support Vector Machine learning algorithm was developed to identify prey captures that occurred throughout the entire foraging trip. Prey capture rates indicated that Macaroni penguins continued to forage beyond the optimal give up time. However, bout-scale analysis revealed individuals terminated diving behaviour for reasons other than patch quality. These findings indicate that individuals make complex foraging decisions in relation to their proximate environment over multiple spatio-temporal scales. |
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394 |
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ISSN |
1432-1793 |
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yes |
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Serial |
2037 |
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Author |
Richard D. Ray, Bryant D. Loomis, Victor Zlotnicki |
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Title |
The mean seasonal cycle in relative sea level from satellite altimetry and gravimetry |
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Year |
2021 |
Publication |
Journal of Geodesy |
Abbreviated Journal |
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Volume |
95 |
Issue |
7 |
Pages |
80 |
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Keywords |
Annual geocenter motion Annual land motion Annual/semiannual cycle Satellite altimetry |
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688 |
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ISSN |
1432-1394 |
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yes |
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Serial |
8610 |
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Author |
Yushiro Fujii, Kenji Satake, Shingo Watada, Tung-Cheng Ho |
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Journal |
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Year |
2021 |
Publication |
Pure and Applied Geophysics |
Abbreviated Journal |
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Volume |
178 |
Issue |
12 |
Pages |
4777-4796 |
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688 |
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ISSN |
1420-9136 |
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yes |
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8411 |
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Title |
Food source diversity, trophic plasticity, and omnivory enhance the stability of a shallow benthic food web from a high-Arctic fjord exposed to freshwater inputs |
Type |
Journal |
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Year |
2021 |
Publication |
Limnology and Oceanography |
Abbreviated Journal |
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Volume |
66 |
Issue |
S1 |
Pages |
S259-S272 |
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Abstract |
Under climate change, many Arctic coastal ecosystems receive increasing amounts of freshwater, with ecological consequences that remain poorly understood. In this study, we investigated how freshwater inputs may affect the small-scale structure of benthic food webs in a low-production high-Arctic fjord (Young Sound, NE Greenland). We seasonally sampled benthic invertebrates from two stations receiving contrasting freshwater inputs: an inner station exposed to turbid and nutrient-depleted freshwater flows and an outer station exposed to lower terrestrial influences. Benthic food web structure was described using a stable isotope approach (?13C and ?15N), Bayesian models, and community-wide metrics. The results revealed the spatially and temporally homogeneous structure of the benthic food web, characterized by high trophic diversity (i.e., a wide community isotopic niche). Such temporal stability and spatial homogeneity mirrors the high degree of trophic plasticity and omnivory of benthic consumers that allows the maintenance of several carbon pathways through the food web despite different food availability. Furthermore, potential large inputs of shelf organic matter together with local benthic primary production (i.e., macroalgae and presumably microphytobenthos) may considerably increase the stability of the benthic food web by providing alternative food sources to locally runoff-impacted pelagic primary production. Future studies should assess beyond which threshold limit a larger increase in freshwater inputs might cancel out these stability factors and lead to marked changes in Arctic benthic ecosystems. |
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1158 |
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ISSN |
1939-5590 |
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yes |
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Call Number |
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Serial |
6791 |
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Title |
Per- and Polyfluoroalkyl Substances Are Positively Associated with Thyroid Hormones in an Arctic Seabird |
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Journal |
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Year |
2021 |
Publication |
Environmental Toxicology and Chemistry |
Abbreviated Journal |
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Volume |
40 |
Issue |
3 |
Pages |
820-831 |
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Keywords |
Avian toxicity Ecotoxicology Endocrine-disrupting compounds Per- and polyfluoroalkyl substance Thyroid hormones |
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Abstract |
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Programme |
330 |
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ISSN |
1552-8618 |
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yes |
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Call Number |
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Serial |
7967 |
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Journal |
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Year |
2021 |
Publication |
Ecology |
Abbreviated Journal |
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Volume |
103 |
Issue |
3 |
Pages |
e3611 |
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Keywords |
Antarctica Asteroidea benthos biometric measurements Echinodermata elemental contents invertebrates marine ecosystems sea stars Southern Ocean stable isotopes subantarctic Islands |
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Abstract |
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Programme |
1044 |
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ISSN |
1939-9170 |
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yes |
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Serial |
8445 |
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Title |
Snow hardness impacts intranivean locomotion of arctic small mammals |
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Journal |
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Year |
2021 |
Publication |
Ecosphere |
Abbreviated Journal |
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Volume |
12 |
Issue |
11 |
Pages |
e03835 |
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Keywords |
Arctic burrowing behavior digging fossorial hardness lemming locomotion rain-on-snow rodent snow subnivean tunnel |
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Abstract |
Fossorial locomotion is often considered as the most energetically costly of all terrestrial locomotion. Small arctic rodents, such as lemmings, dig tunnels not only in the soil but also through the snowpack, which is present for over 8 months of the year. Lemmings typically dig in the softest snow layer called the depth hoar but with climate change, melt-freeze and rain-on-snow (ROS) events are expected to increase in the Arctic, leading to a higher frequency of hardened snowpacks. We assessed the impacts of snow hardness on the locomotion of two lemming species showing different morphological adaptations for digging. We hypothesized that an increase in snow hardness would (1) decrease lemming performance and (2) increase their effort while digging, but those responses would differ between lemming species. We exposed four brown lemmings (Lemmus trimucronatus) and three collared lemmings (Dicrostonyx groenlandicus) to snow of different hardness (soft, hard, and ROS) during 30-min trials (n = 63 trials) in a cold room and filmed their behavior. We found that the digging speed and tunnel length of both species decreased with snow hardness and density, underlining the critical role of snow properties in affecting lemming digging performance. During the ROS trials, time spent digging by lemmings increased considerably and they also started using their incisors to help break the hard snow, validating our second hypothesis. Overall, digging performance was higher in collared lemmings, the species showing more morphological adaptations to digging, than in brown lemmings. We conclude that the digging performance of lemming is highly dependent on snowpack hardness and that the anticipated increase in ROS events may pose a critical energetic challenge for arctic rodent populations. |
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1042 |
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ISSN |
2150-8925 |
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yes |
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Call Number |
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Serial |
8028 |
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Title |
Underwater photogrammetry for close-range 3D imaging of dry-sensitive objects: The case study of cephalopod beaks |
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Journal |
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Year |
2021 |
Publication |
Ecology and Evolution |
Abbreviated Journal |
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Volume |
11 |
Issue |
12 |
Pages |
7730-7742 |
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Keywords |
3D models cephalopod beaks dry-sensitive material micro-CT scanning micro-photogrammetry underwater photogrammetry |
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Abstract |
Technical advances in 3D imaging have contributed to quantifying and understanding biological variability and complexity. However, small, dry-sensitive objects are not easy to reconstruct using common and easily available techniques such as photogrammetry, surface scanning, or micro-CT scanning. Here, we use cephalopod beaks as an example as their size, thickness, transparency, and dry-sensitive nature make them particularly challenging. We developed a new, underwater, photogrammetry protocol in order to add these types of biological structures to the panel of photogrammetric possibilities. We used a camera with a macrophotography mode in a waterproof housing fixed in a tank with clear water. The beak was painted and fixed on a colored rotating support. Three angles of view, two acquisitions, and around 300 pictures per specimen were taken in order to reconstruct a full 3D model. These models were compared with others obtained with micro-CT scanning to verify their accuracy. The models can be obtained quickly and cheaply compared with micro-CT scanning and have sufficient precision for quantitative interspecific morphological analyses. Our work shows that underwater photogrammetry is a fast, noninvasive, efficient, and accurate way to reconstruct 3D models of dry-sensitive objects while conserving their shape. While the reconstruction of the shape is accurate, some internal parts cannot be reconstructed with photogrammetry as they are not visible. In contrast, these structures are visible using reconstructions based on micro-CT scanning. The mean difference between both methods is very small (10?5 to 10?4 mm) and is significantly lower than differences between meshes of different individuals. This photogrammetry protocol is portable, easy-to-use, fast, and reproducible. Micro-CT scanning, in contrast, is time-consuming, expensive, and nonportable. This protocol can be applied to reconstruct the 3D shape of many other dry-sensitive objects such as shells of shellfish, cartilage, plants, and other chitinous materials. |
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109 |
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ISSN |
2045-7758 |
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yes |
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8092 |
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Author |
Niels M. Schmidt, Olivier Gilg, Jon Aars, Rolf A. Ims |
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Title |
Fat, Furry, Flexible, and Functionally Important: Characteristics of Mammals Living in the Arctic |
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Book |
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Year |
2021 |
Publication |
Arctic Ecology |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
357-384 |
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Keywords |
arctic ecosystems Arctic mammals climate change deglaciation food webs homeotherms low mammal species diversity primary production |
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Abstract |
Mammals constitute a group of vertebrates that share a number of unique characteristics,such as nursing their young with milk, and having hair. The pattern of low mammal species diversity in the Arctic probably reflects a combination of mainly two driving factors: first, being homeotherms, mammals require a substantial amount of energy to sustain the various life processes, and the arctic regions are characterized by a very low availability of energy due to short seasons for primary production. Secondly, the occurrence of arctic mammals today reflects the reinvasion of the mammal species into the Arctic as the ecosystems were re-established following the deglaciation. This chapter discusses the characteristics of the arctic mammals, including their unique adaptations to life, and their role as both consumer and food base in the arctic ecosystems. Climate change in the Arctic may also alter the interactions within food webs. |
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1036 |
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978-1-118-84658-2 |
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yes |
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8489 |
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2021 |
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1151 |
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yes |
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6711 |
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