scholarly journals Bioluminescent backlighting illuminates the complex visual signals of a social squid in the deep sea

2020 ◽  
Vol 117 (15) ◽  
pp. 8524-8531 ◽  
Author(s):  
Benjamin P. Burford ◽  
Bruce H. Robison

Visual signals rapidly relay information, facilitating behaviors and ecological interactions that shape ecosystems. However, most known signaling systems can be restricted by low light levels—a pervasive condition in the deep ocean, the largest inhabitable space on the planet. Resident visually cued animals have therefore been hypothesized to have simple signals with limited information-carrying capacity. We used cameras mounted on remotely operated vehicles to study the behavior of the Humboldt squid, Dosidicus gigas, in its natural deep-sea habitat. We show that specific pigmentation patterns from its diverse repertoire are selectively displayed during foraging and in social scenarios, and we investigate how these behaviors may be used syntactically for communication. We additionally identify the probable mechanism by which D. gigas, and related squids, illuminate these patterns to create visual signals that can be readily perceived in the deep, dark ocean. Numerous small subcutaneous (s.c.) photophores (bioluminescent organs) embedded throughout the muscle tissue make the entire body glow, thereby backlighting the pigmentation patterns. Equipped with a mechanism by which complex information can be rapidly relayed through a visual pathway under low-light conditions, our data suggest that the visual signals displayed by D. gigas could share design features with advanced forms of animal communication. Visual signaling by deep-living cephalopods will likely be critical in understanding how, and how much, information can be shared in one of the planet’s most challenging environments for visual communication.

GigaScience ◽  
2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Rute R da Fonseca ◽  
Alvarina Couto ◽  
Andre M Machado ◽  
Brona Brejova ◽  
Carolin B Albertin ◽  
...  

ABSTRACT Background The giant squid (Architeuthis dux; Steenstrup, 1857) is an enigmatic giant mollusc with a circumglobal distribution in the deep ocean, except in the high Arctic and Antarctic waters. The elusiveness of the species makes it difficult to study. Thus, having a genome assembled for this deep-sea–dwelling species will allow several pending evolutionary questions to be unlocked. Findings We present a draft genome assembly that includes 200 Gb of Illumina reads, 4 Gb of Moleculo synthetic long reads, and 108 Gb of Chicago libraries, with a final size matching the estimated genome size of 2.7 Gb, and a scaffold N50 of 4.8 Mb. We also present an alternative assembly including 27 Gb raw reads generated using the Pacific Biosciences platform. In addition, we sequenced the proteome of the same individual and RNA from 3 different tissue types from 3 other species of squid (Onychoteuthis banksii, Dosidicus gigas, and Sthenoteuthis oualaniensis) to assist genome annotation. We annotated 33,406 protein-coding genes supported by evidence, and the genome completeness estimated by BUSCO reached 92%. Repetitive regions cover 49.17% of the genome. Conclusions This annotated draft genome of A. dux provides a critical resource to investigate the unique traits of this species, including its gigantism and key adaptations to deep-sea environments.


Author(s):  
Anna Zhadan

Two new species of Cossura Webster & Benedict, 1887 were found in material collected during sampling from the terminal lobes of the Congo deep-sea fan. They were described using light and scanning electron microscopy. Cossura platypus sp. nov. has 15–17 thoracic chaetigers, a prostomium longer than it is wide, with a widely rounded anterior margin, an abruptly expanded posterior prostomial ring the same length as the peristomium, without a mid-ventral notch, a branchial filament attached to the midlength of chaetiger 3, and a pygidium with three anal cirri. Cossura platypus sp. nov. is similar to C. brunnea Fauchald, 1972 but differs in the shape of the prostomium, which is widely rounded anteriorly in C. platypus sp. nov. and is broadly triangular in C. brunnea; furthermore, C. platypus sp. nov.is uniformly pale, whereas C. brunnea has dark pigmentation. Cossura candida Hartman, 1955 differs from C. platypus sp. nov. in the conical shape of the prostomium and 24–35 thoracic chaetigers. Cossura flabelligera sp. nov. has 16–19 thoracic chaetigers, a conical prostomium, and a branchial filament arising from the posterior part of chaetiger 2; the entire body, including the chaetae, is covered by a thick mucous sheath similar to the tunic of flabelligerids. Cossura flabelligera sp. nov. resembles C. longocirrata Webster & Benedict, 1887 in the position of the branchial filament, the shape of the prostomium, and the number of thoracic chaetigers; it differs in having a thick mucous sheath. This character seems to be unique for the Cossuridae.


2015 ◽  
Vol 218 (2) ◽  
pp. 265-275 ◽  
Author(s):  
H. Rosen ◽  
W. Gilly ◽  
L. Bell ◽  
K. Abernathy ◽  
G. Marshall

2006 ◽  
Vol 2 (5) ◽  
pp. 711-743 ◽  
Author(s):  
L. C. Skinner

Abstract. Given the magnitude and dynamism of the deep marine carbon reservoir, it is almost certain that past glacial – interglacial fluctuations in atmospheric CO2 have relied at least in part on changes in the carbon storage capacity of the deep sea. To date, physical ocean circulation mechanisms that have been proposed as viable explanations for glacial – interglacial CO2 change have focussed almost exclusively on dynamical or kinetic processes. Here, a simple mechanism is proposed for increasing the carbon storage capacity of the deep sea that operates via changes in the volume of southern-sourced deep-water filling the ocean basins, as dictated by the hypsometry of the ocean floor. It is proposed that a water-mass that occupies more than the bottom 3 km of the ocean will essentially determine the carbon content of the marine reservoir. Hence by filling this interval with southern-sourced deep-water (enriched in dissolved CO2 due to its particular mode of formation) the amount of carbon sequestered in the deep sea may be greatly increased. A simple box-model is used to test this hypothesis, and to investigate its implications. It is suggested that up to 70% of the observed glacial – interglacial CO2 change might be explained by the replacement of northern-sourced deep-water below 2.5 km water depth by its southern counterpart. Most importantly, it is found that an increase in the volume of southern-sourced deep-water allows glacial CO2 levels to be simulated easily with only modest changes in Southern Ocean biological export or overturning. If incorporated into the list of contributing factors to marine carbon sequestration, this mechanism may help to significantly reduce the "deficit" of explained glacial – interglacial CO2 change.


2012 ◽  
Vol 29 (2) ◽  
pp. 109-114 ◽  
Author(s):  
J. Feige ◽  
A. Wallner ◽  
S. R. Winkler ◽  
S. Merchel ◽  
L. K. Fifield ◽  
...  

AbstractAn enhanced concentration of 60Fe was found in a deep ocean crust in 2004 in a layer corresponding to an age of ∼2 Myr. The confirmation of this signal in terrestrial archives as supernova-induced and the detection of other supernova-produced radionuclides is of great interest. We have identified two suitable marine sediment cores from the South Australian Basin and estimated the intensity of a possible signal of the supernova-produced radionuclides 26Al, 53Mn, 60Fe, and the pure r-process element 244Pu in these cores. The finding of these radionuclides in a sediment core might allow us to improve the time resolution of the signal and thus to link the signal to a supernova event in the solar vicinity ∼2 Myr ago. Furthermore, it gives us an insight into nucleosynthesis scenarios in massive stars, condensation into dust grains and transport mechanisms from the supernova shell into the solar system.


2021 ◽  
Author(s):  
Anna Joy Drury ◽  
Thomas Westerhold ◽  
David A. Hodell ◽  
Mitchell Lyle ◽  
Cédric M. John ◽  
...  

<p>During the late Miocene, meridional sea surface temperature gradients, deep ocean circulation patterns, and continental configurations evolved to a state similar to modern day. Deep-sea benthic foraminiferal stable oxygen (δ<sup>18</sup>O) and carbon (δ<sup>13</sup>C) isotope stratigraphy remains a fundamental tool for providing accurate chronologies and global correlations, both of which can be used to assess late Miocene climate dynamics. Until recently, late Miocene benthic δ<sup>18</sup>O and δ<sup>13</sup>C stratigraphies remained poorly constrained, due to relatively poor global high-resolution data coverage.</p><p>Here, I present ongoing work that uses high-resolution deep-sea foraminiferal stable isotope records to improve late Miocene (chrono)stratigraphy. Although challenges remain, the coverage of late Miocene benthic δ<sup>18</sup>O and δ<sup>13</sup>C stratigraphies has drastically improved in recent years, with high-resolution records now available across the Atlantic and Pacific Oceans. The recovery of these deep-sea records, including the first astronomically tuned, deep-sea integrated magneto-chemostratigraphy, has also helped to improve the late Miocene geological timescale. Finally, I will briefly touch upon how our understanding of late Miocene climate evolution has improved, based on the high-resolution deep-sea archives that are now available.</p>


Author(s):  
Eva Ramirez-Llodra ◽  
Maria Baker ◽  
Paul Tyler

Healthy oceans are essential to maintain a healthy planet, but the ocean is facing many challenges that need urgent attention. Robust scientific data and innovative technological, policy, and industrial solutions are essential to support sound management of the deep-ocean natural capital, both within and beyond national jurisdiction, to ensure future healthy and productive oceans. As with many systems on Earth, there is a delicate ecological balance in the deep ocean that must be maintained. Understanding the interactions of the different components of natural capital in the deep sea is complex, as many of the variables are interlinked and many have cumulative and synergistic effects on the ecosystem. Add to this the global and changing effects of climate change and ocean acidification, and legislators and managers have a tough job ahead to account for all of these issues when designing appropriate conservation measures. It is important that scientists work hand in hand with multiple stakeholders to identify issues and research needs that contribute to enhancing knowledge and the science needed for decision-making to help towards securing a healthy future for our deep-ocean ecosystems and their long-term natural capital.


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