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Ward P, Barord GJ, Schauer A, Veloso J. Comparative Trophic Levels of Phragmocone-Bearing Cephalopods (Nautiloids, Ammonoids, and Sepiids). Integr Comp Biol 2023; 63:1285-1297. [PMID: 37994658 DOI: 10.1093/icb/icad125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 11/06/2023] [Accepted: 11/09/2023] [Indexed: 11/24/2023] Open
Abstract
Cephalopods are among many marine animals that through some combination of habit and/or habitat have proven difficult to study, especially understanding their trophic positions in marine communities. Stable isotope analyses have provided powerful tools for discovering quantitative aspects about the ecology and food sources of many cephalopod species. Here, we present new gut content and isotopic data (carbon and nitrogen isotopes) from phragmocone-bearing cephalopods (both ectocochleates, as well as those with internal, hard part buoyancy maintenance apparatuses). To this, we also include observations from baited remote underwater video systems to describe feeding habits and potential prey types to correlate with gut contents analyses. These data come from extant Allonautilus, Nautilus, and Sepia species, as well as from extinct nautiloids and ammonites. Extant nautiloids occupy a different isotopic niche than all other cephalopod groups where such data have been published to date. We conclude that these species are obligate scavengers rather than predators on any living species in their environments. Extant Nautilus and Allonautilus also demonstrate different patterns of functional allometry of nitrogen isotope values over ontogeny than do most other cephalopods (or animals in general), by showing decreasing nitrogen isotope levels during ontogeny. This pattern is shown to be different in Sepia and the yet small number of ammonite cephalopods studied to date, supporting the increasingly accepted view that ammonites were far closer to coleoids in basic biology than nautiloids. Overall, phragmocone-bearing cephalopods appear fundamentally different ecologically than cephalopods without this kind of buoyancy system. Of these groups, nautiloids appear to live a low-energy existence that allows them to subsist on energy-poor food sources, such as crustacean molts, as well as being able to scavenge in low oxygen basins where rare food falls, such as dead fish, remain unobtainable by most other animals.
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Affiliation(s)
- Peter Ward
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Gregory J Barord
- Department of Marine Sciences, Central Campus, Des Moines, IA, 50309, USA
| | - Andrew Schauer
- Department of Earth and Space Sciences, University of Washington, Seattle, 98195 WA, USA
| | - Job Veloso
- Department of Biology, University of Washington, Seattle, WA 98195, USA
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Lonardi A, Putti M, De Bacco C. Multicommodity routing optimization for engineering networks. Sci Rep 2022; 12:7474. [PMID: 35523923 PMCID: PMC9076927 DOI: 10.1038/s41598-022-11348-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 04/21/2022] [Indexed: 11/12/2022] Open
Abstract
Optimizing passengers routes is crucial to design efficient transportation networks. Recent results show that optimal transport provides an efficient alternative to standard optimization methods. However, it is not yet clear if this formalism has empirical validity on engineering networks. We address this issue by considering different response functions-quantities determining the interaction between passengers-in the dynamics implementing the optimal transport formulation. Particularly, we couple passengers' fluxes by taking their sum or the sum of their squares. The first choice naturally reflects edges occupancy in transportation networks, however the second guarantees convergence to an optimal configuration of flows. Both modeling choices are applied to the Paris metro. We measure the extent of traffic bottlenecks and infrastructure resilience to node removal, showing that the two settings are equivalent in the congested transport regime, but different in the branched one. In the latter, the two formulations differ on how fluxes are distributed, with one function favoring routes consolidation, thus potentially being prone to generate traffic overload. Additionally, we compare our method to Dijkstra's algorithm to show its capacity to efficiently recover shortest-path-like graphs. Finally, we observe that optimal transport networks lie in the Pareto front drawn by the energy dissipated by passengers, and the cost to build the infrastructure.
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Affiliation(s)
- Alessandro Lonardi
- Max Planck Institute for Intelligent Systems, Cyber Valley, Tübingen, 72076, Germany.
| | - Mario Putti
- Department of Mathematics "Tullio Levi-Civita", University of Padua, Via Trieste 63, Padua, Italy
| | - Caterina De Bacco
- Max Planck Institute for Intelligent Systems, Cyber Valley, Tübingen, 72076, Germany
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David Wells RJ, Rooker JR, Addis P, Arrizabalaga H, Baptista M, Bearzi G, Fraile I, Lacoue-Labarthe T, Meese EN, Megalofonou P, Rosa R, Sobrino I, Sykes AV, Villanueva R. Regional patterns of δ 13C and δ 15N for European common cuttlefish ( Sepia officinalis) throughout the Northeast Atlantic Ocean and Mediterranean Sea. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210345. [PMID: 34540247 PMCID: PMC8437227 DOI: 10.1098/rsos.210345] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 08/12/2021] [Indexed: 06/13/2023]
Abstract
Stable isotope compositions of carbon and nitrogen (expressed as δ 13C and δ 15N) from the European common cuttlefish (Sepia officinalis) were measured in order to evaluate the utility of using these natural tracers throughout the Northeast Atlantic Ocean and Mediterranean Sea (NEAO-MS). Mantle tissue was obtained from S. officinalis collected from 11 sampling locations spanning a wide geographical coverage in the NEAO-MS. Significant differences of both δ 13C and δ 15N values were found among S. officinalis samples relative to sampling location. δ 13C values did not show any discernable spatial trends; however, a distinct pattern of lower δ 15N values in the Mediterranean Sea relative to the NEAO existed. Mean δ 15N values of S. officinalis in the Mediterranean Sea averaged 2.5‰ lower than conspecifics collected in the NEAO and showed a decreasing eastward trend within the Mediterranean Sea with the lowest values in the most eastern sampling locations. Results suggest δ 15N may serve as a useful natural tracer for studies on the population structure of S. officinalis as well as other marine organisms throughout the NEAO-MS.
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Affiliation(s)
- R. J. David Wells
- Department of Marine Biology, Texas A&M University, 1001 Texas Clipper Road, Galveston, TX 77553, USA
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX 77843, USA
| | - Jay R. Rooker
- Department of Marine Biology, Texas A&M University, 1001 Texas Clipper Road, Galveston, TX 77553, USA
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX 77843, USA
| | - Piero Addis
- Department of Environmental and Life Science, University of Cagliari, Via Fiorelli 1, 09126 Cagliari, Italy
| | - Haritz Arrizabalaga
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Herrera Kaia-Portualdea z/g, 20110 Pasaia – Gipuzkoa, Spain
| | - Miguel Baptista
- Marine and Environmental Sciences Centre, Laboratorio Maritimo da Guia, Faculdade de Ciencias, Universidade de Lisboa, Avenida Nossa Senhora do Cabo, 939, 2750-374 Cascais, Portugal
| | - Giovanni Bearzi
- Dolphin Biology and Conservation, Cordenons, Pordenone, Italy
| | - Igaratza Fraile
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Herrera Kaia-Portualdea z/g, 20110 Pasaia – Gipuzkoa, Spain
| | - Thomas Lacoue-Labarthe
- LIttoral Environnement et Sociétés (LIENSs) – UMR 7266 Bâtiment ILE, 2, rue Olympe de Gouges, 17000 La Rochelle, France
| | - Emily N. Meese
- Department of Marine Biology, Texas A&M University, 1001 Texas Clipper Road, Galveston, TX 77553, USA
| | - Persefoni Megalofonou
- Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece
| | - Rui Rosa
- Marine and Environmental Sciences Centre, Laboratorio Maritimo da Guia, Faculdade de Ciencias, Universidade de Lisboa, Avenida Nossa Senhora do Cabo, 939, 2750-374 Cascais, Portugal
| | - Ignacio Sobrino
- Instituto Español de Oceanografía, Puerto Pesquero s/n, 11006, Cádiz, Spain
| | - Antonio V. Sykes
- Center of Marine Sciences, Universidade do Algarve Campus de Gambelas, 8005-139 Faro, Portugal
| | - Roger Villanueva
- Institut de Ciències del Mar (CSIC), Passeig Maritim, 37-49, 08003, Barcelona, Spain
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