Natural Sciences

Active buoyancy adjustment increases dispersal potential in benthic marine animals

Hamel J-F, Sun J, Gianasi BL, Montgomery EM, Kenchington EL, Burel B, Rowe S, Winger PD, Mercier A. Active buoyancy adjustment increases dispersal potential in benthic marine animals. Journal of Animal Ecology [Internet]. 2019 . Available from: https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2656.12943
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $42.00
Type: Journal Article

While the study of dispersal and connectivity in the ocean typically centers on pelagic species and planktonic larval stages of benthic species, the present work explores an overlooked locomotor means in post‐settlement benthic stages that redefines their dispersal potential.

Members of the echinoderm class Holothuroidea colonize a diversity of marine environments worldwide, where they play key ecological and economical roles, making their conservation a priority. Holothuroids are commonly called sea cucumbers or sea slugs to reflect their slow movements and are assumed to disperse chiefly through pelagic larvae.

The present study documents and explores their unexpected ability to actively modify their buoyancy, leading them to tumble or float at speeds orders of magnitudes faster than through benthic crawling. Two focal species representing different taxonomic orders, geographic distributions and reproductive strategies were studied over several years.

Active buoyancy adjustment (ABA) was achieved through a rapid increase in seawater to flesh ratio by up to 740%, leading to bloating, and simultaneously detachment from the substrate. It occurred as early as 6 months post settlement in juveniles and was recorded in wild adult populations. In experimental trials, ABA was triggered by high conspecific density, decreasing salinity and increasing water turbidity. Based on field video footage, ABA‐assisted movements generated speeds of up to 90 km d−1.

These findings imply that displacement during planktonic larval stages may not supersede the locomotor capacity of benthic stages, challenging the notion of sedentarity. Combining the present results and anecdotal reports, ABA emerges as a generalized means of dispersal among benthic animals, with critical implications for worldwide management and conservation of commercially and ecologically significant species.

Living with Pigments: The Colour Palette of Antarctic Life

Marizcurrena JJosé, Cerdá MFernanda, Alem D, Castro-Sowinski S. Living with Pigments: The Colour Palette of Antarctic Life. In: Castro-Sowinski S The Ecological Role of Micro-organisms in the Antarctic Environment. The Ecological Role of Micro-organisms in the Antarctic Environment. Cham: Springer International Publishing; 2019. pp. 65 - 82. Available from: https://link.springer.com/chapter/10.1007/978-3-030-02786-5_4
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $29.95
Type: Book Chapter

The production of pigments is a common feature that may help microorganisms to cope with the harsh conditions found in Antarctica. They have functions such as protection against UV irradiation and superoxide and nitrogen reactive species (antioxidant activity) and modulation of membrane fluidity under cold stress. In addition, they act as antibiotics, modulating the microbial communities in their natural environments, and harvest light for increasing the efficiency of photosynthesis, thus influencing the biogeochemical cycles. This chapter deals with the chemistry and the biological role of microbial pigments (except chlorophylls) in the Antarctic environment and also includes a brief overview of the potential biotechnological use of pigments.

The Ecological Role of Micro-organisms in the Antarctic Environment: Marine Fungi Associated with Antarctic Macroalgae

Ogaki MB, de Paula MT, Ruas D, Pellizzari FM, García-Laviña CX, Rosa LH. The Ecological Role of Micro-organisms in the Antarctic Environment: Marine Fungi Associated with Antarctic Macroalgae. (Castro-Sowinski S). Cham: Springer International Publishing; 2019 pp. 239 - 255. Available from: https://link.springer.com/chapter/10.1007/978-3-030-02786-5_11
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $29.95
Type: Book

Fungi are well known for their important roles in terrestrial ecosystems, but filamentous and yeast forms are also active components of microbial communities from marine ecosystems. Marine fungi are particularly abundant and relevant in coastal systems where they can be found in association with large organic substrata, like seaweeds. Antarctica is a rather unexplored region of the planet that is being influenced by strong and rapid climate change. In the past decade, several efforts have been made to get a thorough inventory of marine fungi from different environments, with a particular emphasis on those associated with the large communities of seaweeds that abound in littoral and infralittoral ecosystems. The algicolous fungal communities obtained were characterized by a few dominant species and a large number of singletons, as well as a balance among endemic, indigenous, and cold-adapted cosmopolitan species. The long-term monitoring of this balance and the dynamics of richness, dominance, and distributional patterns of these algicolous fungal communities is proposed to understand and model the influence of climate change on the maritime Antarctic biota. In addition, several fungal isolates from marine Antarctic environments have shown great potential as producers of bioactive natural products and enzymes and may represent attractive sources of biotechnological products.

Feeding ecology of invasive lionfish (Pterois volitans and Pterois miles) in the temperate and tropical western Atlantic

Peake J, Bogdanoff AK, Layman CA, Castillo B, Reale-Munroe K, Chapman J, Dahl K, III WFPatters, Eddy C, Ellis RD, et al. Feeding ecology of invasive lionfish (Pterois volitans and Pterois miles) in the temperate and tropical western Atlantic. Biological Invasions [Internet]. 2018 ;20(9):2567 - 2597. Available from: https://link.springer.com/article/10.1007%2Fs10530-018-1720-5
Freely available?: 
Yes
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $39.95
Type: Journal Article

Numerous location-based diet studies have been published describing different aspects of invasive lionfish (Pterois volitans and Pterois miles) feeding ecology, but there has been no synthesis of their diet composition and feeding patterns across regional gradients. 8125 lionfish stomachs collected from 10 locations were analyzed to provide a generalized description of their feeding ecology at a regional scale and to compare their diet among locations. Our regional data indicate lionfish in the western Atlantic are opportunistic generalist carnivores that consume at least 167 vertebrate and invertebrate prey species across multiple trophic guilds, and carnivorous fish and shrimp prey that are not managed fishery species and not considered at risk of extinction by the International Union for Conservation of Nature disproportionately dominate their diet. Correlations between lionfish size and their diet composition indicate lionfish in the western Atlantic transition from a shrimp-dominated diet to a fish-dominated diet through ontogeny. Lionfish total length (TL) (mm) was found to predict mean prey mass per stomach (g) by the following equation mean prey mass =0.0002*TL1.6391, which can be used to estimate prey biomass consumption from lionfish length-frequency data. Our locational comparisons indicate lionfish diet varies considerably among locations, even at the group (e.g., crab) and trophic guild levels. The Modified Index of Relative Importance developed specifically for this study, calculated as the frequency of prey a × the number of prey a, can be used in other diet studies to assess prey importance when prey mass data are not available. Researchers and managers can use the diet data presented in this study to make inference about lionfish feeding ecology in areas where their diet has yet to be described. These data can be used to guide research and monitoring efforts, and can be used in modeling exercises to simulate the potential effects of lionfish on marine food webs. Given the large variability in lionfish diet composition among locations, this study highlights the importance of continued location-based diet assessments to better inform local management activities.

Teasing apart the different size pools of extracellular enzymatic activity in the ocean

Baltar F, De Corte D, Thomson B, Yokokawa T. Teasing apart the different size pools of extracellular enzymatic activity in the ocean. Science of The Total Environment [Internet]. 2019 ;660:690 - 696. Available from: https://www.sciencedirect.com/science/article/pii/S0048969719300907
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $41.95
Type: Journal Article

Extracellular enzymatic activity (EEA) is performed by cell-associated and cell-free (i.e., “dissolved”) enzymes. This cell-free fraction is operationally defined as passing through a 0.22 μm filter. The contribution of cell-free to total EEA is comparable to the cell-associated counterpart, so it is critical to understand what controls the relative importance of cell-free versus cell-associated EEA. However, attempts to tease apart the contribution of EEAs in the so-called dissolved fraction (<0.22 μm) in general, and of the nanoparticle size fraction (0.020–0.20 μm) in particular, to the total EEA pool are lacking. Here we performed experiments with Northern and Southern Hemisphere coastal waters to characterize the potential contribution of that nanoparticle fraction to the total EEA fraction of alkaline phosphatase, beta-glucosidase and leucine aminopeptidase. We found a significant contribution (in both hemispheres) of the nanoparticle fraction to the total EEA pool (up to 53%) that differed depending on the enzyme type and location. Collectively, our results indicate that a significant fraction of the so-called “dissolved EEA” is not really dissolved but associated to nanoparticles, colloidal nanogels and/or viruses. Thus, the total marine EEA pool can actually be divided into a cell-associated, undissolved-cell-free (associated to nano-particle of different origins such as viruses and nanogels) and a dissolved-cell-free pools. Our results also imply that the dissolved EEA pool is more complex than thus far anticipated. Future research will be now needed to further characterize the factors controlling the relative importance of these different pools of EEA, which are key in the recycling of organic matter in the ocean.

Rafting behaviour of seabirds as a proxy to describe surface ocean currents in the Balearic Sea

Sánchez-Román A, Gómez-Navarro L, Fablet R, Oro D, Mason E, Arcos JM, Ruiz S, Pascual A. Rafting behaviour of seabirds as a proxy to describe surface ocean currents in the Balearic Sea. Scientific Reports [Internet]. 2019 ;9(1). Available from: https://www.nature.com/articles/s41598-018-36819-w
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Spatio-temporal variability of surface geostrophic mesoscale currents in the Balearic Sea (western Mediterranean) is characterized from satellite altimetry in combination with in-situ velocity measurements collected, among others, by drifting buoys, gliders and high-frequency radar. Here, we explore the use of tracking data from living organisms in the Balearic Sea as an alternative way to acquire in-situ velocity measurements. Specifically, we use GPS-tracks of resting Scopoli’s shearwaters Calonectris diomedea, that act as passive drifters, and compare them with satellite-derived velocity patterns. Results suggest that animal-borne GPS data can be used to identify rafting behaviour outside of the breeding colonies and, furthermore, as a proxy to describe local sea surface currents. Four rafting patterns were identified according to the prevailing driving forces responsible for the observed trajectories. We find that 76% of the bird trajectories are associated with the combined effects of slippage and Ekman drift and/or surface drag; 59% are directly driven by the sea surface currents. Shearwaters are therefore likely to be passively transported by these driving forces while resting. The tracks are generally consistent with the mesoscale features observed in satellite data and identified with eddy-tracking software.

Cetacean morbillivirus, a journey from land to sea and viceversa

Di Guardo G, Mazzariol S. Cetacean morbillivirus, a journey from land to sea and viceversa. [Internet]. 2019 . Available from: https://marxiv.org/znvpk/
Freely available?: 
Yes
Summary available?: 
No
Type: Manuscript

Cetacean Morbillivirus, the most relevant pathogen impacting the health and conservation of cetaceans worldwide, has shown in recent years an increased tendency to cross “interspecies barriers”, thereby giving rise to disease and mortality outbreaks in free-ranging dolphins and whales. This "Personal View" deals with the evolutionary “trajectories” of this viral pathogen, likely originating from Rinderpest Virus, along with its "journey" from land to sea (and viceversa), mimicking that of cetaceans' terrestrial ancestors.

Foraging distribution of a tropical seabird supports Ashmole’s hypothesis of population regulation

Oppel S, Beard A, Fox D, Mackley E, Leat E, Henry L, Clingham E, Fowler N, Sim J, Sommerfeld J, et al. Foraging distribution of a tropical seabird supports Ashmole’s hypothesis of population regulation. Behavioral Ecology and Sociobiology [Internet]. 2015 ;69(6):915 - 926. Available from: https://link.springer.com/article/10.1007%2Fs00265-015-1903-3
Freely available?: 
Yes
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $39.95
Type: Journal Article

Many animals reproduce in large aggregations, which can vary in size from dozens to millions of individuals across species, time and space. The size of breeding colonies is a complex trade-off between multiple costs and benefits to an individual’s fitness, but the mechanisms by which colony size affects fitness are still poorly understood. One important cost of breeding in a large colony is the spatial constraint in resource use due to the need to regularly return to a central location. Large aggregations, like seabird breeding colonies, may therefore deplete food resources near the colony, forcing individuals to travel farther to find food, which may ultimately limit their reproductive output and population size. This hypothesis, proposed in 1963 by Ashmole for tropical oceanic islands, has so far not been tested at tropical seabird colonies, where food availability is less predictable than in colder waters. We compare the foraging distribution of a common tropical seabird, the masked booby Sula dactylatra, breeding on two islands in the South Atlantic that differ in the size of the breeding seabird community by 2 orders of magnitude, but are surrounded by similar oligotrophic waters. Foraging trips from the island with the smaller colony were on average 221 km (61 %) and 18.0 h (75 %) shorter because birds from the smaller colony rarely spent the night at sea and foraged on average 64 km (46 %) closer to the colony. Energy expenditure was significantly lower, and nest survival higher (47 vs. 37 %, n = 371) on the island with the smaller colony. These results are fully consistent with the predictions from Ashmole’s hypothesis and indicate that competition for food around tropical oceanic seabird colonies may indeed be a limiting factor for populations. Identifying important feeding areas for seabirds based on their foraging range may need to account for colony size of both the target and potential competitor species.

Foraging ecology of tropicbirds breeding in two contrasting marine environments in the tropical Atlantic

Diop N, Zango L, Beard A, Ba CT, Ndiaye PI, Henry L, Clingham E, Oppel S, González-Solís J. Foraging ecology of tropicbirds breeding in two contrasting marine environments in the tropical Atlantic. Marine Ecology Progress Series [Internet]. 2018 ;607:221 - 236. Available from: https://www.int-res.com/abstracts/meps/v607/p221-236/
Freely available?: 
Yes
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $5344.87
Type: Journal Article

Studying the feeding ecology of seabirds is important not only to understand basic aspects of their ecology and threats but also for the conservation of marine ecosystems. In this regard, tropical seabirds have been relatively neglected, and in particular the trophic ecology of tropicbirds is scarcely known. We combined GPS tracking, environmental variables and sampling of regurgitates during incubation and brooding to understand the feeding ecology of red-billed tropicbirds Phaethon aethereus as well as how foraging strategies may change between 2 contrasting marine environments: a coastal island in the Canary Current upwelling (Îles de la Madeleine) and an oceanic island in the middle of the south Atlantic (St Helena). Tropicbirds breeding on the Îles de la Madeleine headed west, foraging on and beyond the shelf slope, probably to associate with subsurface predators which bring pelagic fish close to the surface. Birds from St Helena showed a greater foraging effort and a strong attraction to areas with the greatest species richness of Scombridae, possibly due to a greater difficulty in finding prey in the oligotrophic oceanic waters. Tropicbirds ranged much beyond the extension of the protected areas around their colonies, indicating that current protected areas are insufficient for these populations. We found no evidence to suspect direct mortality of tropicbirds in regional fisheries, but overexploitation of small epipelagic fish and tuna may decrease feeding opportunities and lead to competition with fisheries. The substantial differences in foraging behaviour demonstrated by individuals from both colonies indicates that caution should be taken when extrapolating foraging patterns of tropical seabirds breeding in contrasting oceanographic environments.

First observation of the courtship behaviour of the giant devil ray Mobula mobular (Myliobatiformes: Mobulidae)

Duffy CAJ, Tindale SC. First observation of the courtship behaviour of the giant devil ray Mobula mobular (Myliobatiformes: Mobulidae). New Zealand Journal of Zoology [Internet]. 2018 ;45(4):387 - 394. Available from: https://www.tandfonline.com/doi/full/10.1080/03014223.2017.1410850
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $50.00
Type: Journal Article

Courtship behaviour of the giant devil ray Mobula mobular is described from northern New Zealand, temperate southwest Pacific Ocean, for the first time. A mating train consisting of a full-term pregnant female and up to four males was observed over a period of 147 minutes. Their behaviour was similar to courtship behaviour observed in other large mobulids. Biting of the female was not observed, possibly due to the female’s use of the surface to prevent males positioning themselves above her. However, the lead male pressed the female’s abdomen and underside each time the female reached or stopped at the surface. The occurrence of pregnant females and mating behaviour off northern North Island confirms breeding occurs in New Zealand waters.

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