Deep-sea foraging pathways: an analysis of randomness and resource exploitation

Paleobiology ◽  
1979 ◽  
Vol 5 (2) ◽  
pp. 107-125 ◽  
Author(s):  
Jennifer A. Kitchell
Keyword(s):  
Deep Sea ◽  
Trace Fossil ◽  
Empirical Modeling ◽  
The Arctic ◽  
Foraging Strategies ◽  
Foraging Efficiency ◽  
Resource Exploitation ◽  
Foraging Patterns ◽  
Risk Of Predation ◽  
Random Behavior

The foraging paradigm of trace fossil theory has historically accorded random behavior to non-food-limited deposit-feeders and non-random behavior to food-limited feeders. A series of randomness measures derived from empirical modeling, simulation modeling, stochastic modeling and probability theory applied to foraging patterns observed in deep-sea bottom photographs from the Arctic and Antarctic yielded a behavioral continuum of increasing non-randomness. A linear regression of trace positions along the continuum to bathymetric data did not substantiate the optimal foraging efficiency-depth dependence model of trace fossil theory, except that all traces exhibited a greater optimization than that of simulated random foraging. It is hypothesized that optimization as evidenced by non-random foraging strategies represents maximization of the cost/benefit ratio of resource exploitation to risk of predation and that individual foraging patterns reflect an exploration response to the morphometry of a patchily distributed food resource. Differential predation and competition may account for the co-occurrence of random and non-random strategies within the same bathymetric zone.

Abyssal traces and megafauna: comparison of productivity, diversity and density in the Arctic and Antarctic

Paleobiology ◽  
1978 ◽  
Vol 4 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Jennifer A. Kitchell ◽  
James F. Kitchell ◽  
G. Leonard Johnson ◽  
Kenneth L. Hunkins
Keyword(s):  
Food Availability ◽  
Deep Sea ◽  
Foraging Strategy ◽  
The Arctic ◽  
Foraging Strategies ◽  
Behavioral Complexity ◽  
Productivity Differential ◽  
The Antarctic ◽  
Trace Density

The megafauna and associated behavioral traces of two deep-sea benthic environments, the central Arctic and Antarctic, with a surface primary productivity differential of 104 were compared to assess the role of food availability in foraging strategy and community structure. Bottom photographs, analyzed for megafauna and trace density and diversity at comparable depths in the Arctic Canada Basin and the Antarctic Bellingshausen Basin, indicated that trace frequency was inversely proportional to organism density but that trace diversity directly reflected organism diversity. Those traces identified in the fossil record to represent efficient foraging strategies, i.e., the Nereites facies, were conspicuously absent at all depths in the Arctic and present at all depths in the Antarctic, in contradiction of the paradigm of increasing behavioral complexity and sediment exploitation as food availability decreases. Presence or absence of surface-grazing organisms seems to exert a greater influence on trace diversity than depth or nutrient supply. Trace density, however, may reflect episodic sedimentation events which intermittently influence the deep-sea trophic regime.

COMPROMISE AND ORIGINAL ACQUISITION: EXPLAINING RIGHTS TO THE ARCTIC

2015 ◽  
Vol 32 (1) ◽  
pp. 149-170 ◽  
Author(s):  
Cara Nine
Keyword(s):  
Political Philosophy ◽  
Natural Resources ◽  
Deep Sea ◽  
Large Degree ◽  
Geographic Area ◽  
Ocean Floor ◽  
The Arctic ◽  
Human Settlement ◽  
The Commons ◽  
Original Acquisition

Abstract:Up until now, political philosophy has explained the acquisition of natural resources, in one way or another, through the terms of human settlement. An agent acquires natural resources by moving into the geographic area that contains these resources. Even how we make claims to the ocean floor depends on settlement — claimants must be adjacent to settled land. This essay extends original acquisition theories so that they can respond to cases that do not presuppose any conditions of human settlement. I suggest that resource rights in the deep sea may be created, alternatively, through acts of compromise. Compromise can alleviate conflict, allowing for claimants to move beyond stalemate to acquire goods. It also allows for a large degree of flexibility in the specification of rights, and thereby can explain nontraditional rights over areas of migration. The tricky part of a theory that grants rights through agreement is explaining why external parties, those not part of the agreement, have a duty to respect those rights. A compromise under certain conditions, I argue, places all persons under a duty to respect the rights created by the compromise. Thus, when two parties compromise, they may acquire goods from the commons — creating a duty for all others to respect the parties’ rights over these goods. Importantly, rights created through compromise are constrained by a set of concerns for those excluded.

The Reproductive Biology of Ophiacantha Bidentata (Echinodermata: Ophiuroidea) From The Rockall Trough

1982 ◽  
Vol 62 (1) ◽  
pp. 45-55 ◽  
Author(s):  
P. A. Tyler ◽  
J. D. Gage
Keyword(s):  
Reproductive Biology ◽  
Deep Water ◽  
Larval Stage ◽  
North Pacific ◽  
Deep Sea ◽  
Direct Development ◽  
The Arctic ◽  
Shallow Waters ◽  
Arctic Seas ◽  
Rockall Trough

INTRODUCTIONOphiacantha bidentata (Retzius) is a widespread arctic-boreal ophiuroid with a circumpolar distribution in the shallow waters of the Arctic seas and penetrating into the deep sea of the.North Atlantic and North Pacific (Mortensen, 1927, 1933a; D'yakonov, 1954). Early observations of this species were confined to defining zoogeo-graphical and taxonomic criteria including the separation of deep water specimens as the variety fraterna (Farran, 1912; Grieg, 1921; Mortensen, 1933a). Mortensen (1910) and Thorson (1936, pp. 18–26) noted the large eggs (o.8 mm diameter) in specimens from Greenland and Thorson (1936) proposed that this species had ‘big eggs rich in yolk, shed directly into the sea. Much reduced larval stage or direct development’. This evidence is supported by observations of O. bidentata from the White and Barents Seas (Semenova, Mileikovsky & Nesis, 1964; Kaufman, 1974)..

Bathymetric patterns of megafaunal assemblages from the arctic deep-sea observatory HAUSGARTEN

2009 ◽  
Vol 56 (10) ◽  
pp. 1856-1872 ◽  
Author(s):  
Thomas Soltwedel ◽  
Nina Jaeckisch ◽  
Nikolaus Ritter ◽  
Christiane Hasemann ◽  
Melanie Bergmann ◽  
...  
Keyword(s):  
Deep Sea ◽  
The Arctic

scholarly journals CHONDRITES-CLADICHNUS ICHNOCOENOSIS FROM THE DEEP-SEA DEPOSITS OF PIERFRANCESCO (CRETACEOUS; ITALY): OXYGEN- OR NUTRIENT-LIMITED?

2022 ◽  
Vol 128 (1) ◽  
Author(s):  
ANDREA BAUCON ◽  
GIROLAMO LO RUSSO ◽  
CARLOS NETO DE CARVALHO ◽  
FABRIZIO FELLETTI
Keyword(s):  
Late Cretaceous ◽  
Deep Sea ◽  
Trace Fossils ◽  
Northern Apennines ◽  
Trace Fossil ◽  
Ecological Succession ◽  
Rhythmic Pattern ◽  
Low Oxygen ◽  
Fossil Assemblage

The Italian Northern Apennines are acknowledged as the place where ichnology was born, but there is comparatively little work about their ichnological record. This study bridges this gap by describing two new ichnosites from the locality of Pierfrancesco, which preserve an abundant, low-disparity trace-fossil assemblage within the Late Cretaceous beds of the M. Cassio Flysch. Results show that lithofacies and ichnotaxa are rhythmically organized. The base of each cycle consists of Megagrapton-bearing calciclastic turbidites, which are overlain by marlstone beds with an abundant, low-disparity assemblage of trace fossils. This includes Chondrites intricatus, C. patulus, C. targionii, C. recurvus and Cladichnus fischeri. The cycle top consists of mudstones with no distinct burrows. The rhythmic pattern of Pierfrancesco reflects a deep-sea ecological succession, in which species and behaviour changed as turbidite-related disturbances altered the seafloor. This study opens the question of whether the Chondrites-Cladichnus ichnocoenosis represents low-oxygen or nutrient-poor settings.

scholarly journals Blue whales (Balaenoptera musculus) optimize foraging efficiency by balancing oxygen use and energy gain as a function of prey density

2015 ◽  
Vol 1 (9) ◽  
pp. e1500469 ◽  
Author(s):  
Elliott Lee Hazen ◽  
Ari Seth Friedlaender ◽  
Jeremy Arthur Goldbogen
Keyword(s):  
Energy Intake ◽  
Prey Density ◽  
Prey Capture ◽  
Energy Gain ◽  
Foraging Strategies ◽  
Foraging Efficiency ◽  
Energetic Efficiency ◽  
Breath Hold ◽  
Balaenoptera Musculus ◽  
Blue Whales

Terrestrial predators can modulate the energy used for prey capture to maximize efficiency, but diving animals face the conflicting metabolic demands of energy intake and the minimization of oxygen depletion during a breath hold. It is thought that diving predators optimize their foraging success when oxygen use and energy gain act as competing currencies, but this hypothesis has not been rigorously tested because it has been difficult to measure the quality of prey that is targeted by free-ranging animals. We used high-resolution multisensor digital tags attached to foraging blue whales (Balaenoptera musculus) with concurrent acoustic prey measurements to quantify foraging performance across depth and prey density gradients. We parameterized two competing physiological models to estimate energy gain and expenditure based on foraging decisions. Our analyses show that at low prey densities, blue whale feeding rates and energy intake were low to minimize oxygen use, but at higher prey densities feeding frequency increased to maximize energy intake. Contrary to previous paradigms, we demonstrate that blue whales are not indiscriminate grazers but instead switch foraging strategies in response to variation in prey density and depth to maximize energetic efficiency.

Exploring environmental factors driving wildfire occurrences in Alaskan tundra

2021 ◽  
Author(s):  
Jiaying He ◽  
Tatiana Loboda ◽  
Nancy French ◽  
Dong Chen
Keyword(s):  
Environmental Factors ◽  
Weather Conditions ◽  
Empirical Modeling ◽  
The Arctic ◽  
Fire Weather ◽  
Fuel Type ◽  
Ignition Probability ◽  
Alaskan Tundra ◽  
Fire Ignition ◽  
Cg Lightning

<p>Tundra fires are common across the pan-Arctic region, particularly in Alaska. Fires lead to significant impacts on terrestrial carbon balance and ecosystem functioning in the tundra. They can even affect the forage availability of herbivorous wildlife and living resources of local human communities. Also, interactions between fire and climate change can enhance the fire impacts on the Arctic ecosystems. However, the drivers and mechanisms of wildland fire occurrences in Alaskan tundra are still poorly understood. Research on modeling contemporary fire probability in the tundra is also lacking. This study focuses on exploring the critical environmental factors controlling wildfire occurrences in Alaskan tundra and modeled the fire ignition probability, accounting for ignition source, fuel types, fire weather conditions, and topography. The fractional cover maps of fuel type components developed Chapter 2 serve as input data for fuel type distribution. The probability of cloud-to-ground (CG) lightning and fire weather conditions are simulated using WRF. Topographic features are also calculated from the Digital Elevation Model (DEM) data. Additionally, fire ignition locations are extracted from Moderate Resolution Imaging Spectroradiometer (MODIS) active fire product for Alaskan tundra from 2001 to 2019. Empirical modeling methods, including RF and logistic regression, are then utilized to model the relationships between environmental factors and wildfire occurrences in the tundra and to evaluate the roles of these factors. Our results suggested that CG lightning is the primary driver controlling fire ignitions in the tundra, while warmer and drier weather conditions also support fires. We also projected future potential of wildland fires in this tundra region with Coupled Model Intercomparison Projects Phase 6 (CMIP6) data. The results of this study highlight the important role of CG lightning in driving tundra fires and that incorporating CG lightning modeling is necessary and essential for fire monitoring and management efforts in the High Northern Latitudes (HNL).</p>

scholarly journals A New Species of Osedax (Siboglinidae: Annelida) From Colonization Experiments in the Arctic Deep Sea

2020 ◽  
Vol 7 ◽  
Author(s):  
Mari Heggernes Eilertsen ◽  
Thomas G. Dahlgren ◽  
Hans Tore Rapp
Keyword(s):  
New Species ◽  
Deep Sea ◽  
The Arctic ◽  
A New Species

Diets and foraging behaviour of red and eastern grey kangaroos in arid shrub land: is feeding behaviour involved in the range expansion of the eastern grey kangaroo into the arid zone?

2004 ◽  
Vol 26 (2) ◽  
pp. 169 ◽  
Author(s):  
TJ Dawson ◽  
KJ McTavish ◽  
BA Ellis
Keyword(s):  
Feeding Behaviour ◽  
Foraging Behaviour ◽  
Arid Zone ◽  
Foraging Strategies ◽  
Foraging Patterns ◽  
Grey Kangaroo ◽  
Macropus Rufus ◽  
Dietary Niche ◽  
Domestic Stock ◽  
Total Feeding

Eastern grey kangaroos (Macropus giganteus) have expanded into arid areas usually the habitat of red kangaroos (Macropus rufus). Extra watering sites for domestic stock is the suggested reason. However, changes in vegetation also have occurred due to grazing from domestic stock. We investigated the foraging strategies of M. giganteus and M. rufus in arid rangeland to see if these are involved in the range changes. Foraging patterns were similar, with both species mostly foraging at night; total feeding times were the same. M. giganteus and M. rufus had differing diets, though there was considerable overlap of 81 - 87%. Both species were highly selective, having similar narrow dietary niche breaths. Differences in plant preferences occurred and though both species had a preference for grass that of M. giganteus was higher. A larger foregut in M. giganteus reinforces its focus on grass. M. rufus also selected dicot forbs and malvaceous sub-shrubs. Both kangaroos showed avoidance of abundant chenopod shrubs (saltbushes and bluebushes) and trees. It is likely that the changes to arid-zone vegetation, with a shift to grass and annual dicot forbs, has been important for the expansion of M. giganteus, possibly combined with the greater availability of water.

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