The Experts below are selected from a list of 5829 Experts worldwide ranked by ideXlab platform
Michael A. Rex - One of the best experts on this subject based on the ideXlab platform.
-
Toward a Conceptual Understanding of β-Diversity in the Deep-Sea Benthos
Annual Review of Ecology Evolution and Systematics, 2015Co-Authors: Craig R. Mcclain, Michael A. RexAbstract:We review patterns and causes of β-diversity in the Deep-Sea Benthos at different spatial scales and for different body sizes. Changes in species composition occurring with depth are generally gradual, the rate of change being a function of the rate of descent. This gradual change can be interrupted by abrupt environmental shifts, such as oxygen minimum zones, and by major topographic features that alter oceanographic conditions. Changes in species composition with depth can involve both species replacement and species loss, leading to nestedness. Horizontal β-diversity is more moderate than that occurring with depth, except at upper bathyal zones impacted by coastal influences. At very large oceanic scales, both environmental filtering and dispersal limitation influence β-diversity. Although many ecological and evolutionary–historical factors must shape β-diversity in the deep sea, energy availability appears to structure community makeup at all scales examined. We recommend that standardized sampling pr...
-
Global bathymetric patterns of standing stock and body size in the Deep-Sea Benthos
Marine Ecology Progress Series, 2006Co-Authors: Michael A. Rex, Ron J. Etter, Craig R. Mcclain, Jody W. Deming, Carol T. Stuart, Jeremy S. Morris, Jenifer Crouse, Nicholas A. Johnson, Rebecca Thies, Renee AveryAbstract:We present the first global-scale analy- sis of standing stock (abundance and biomass) for 4 major size classes of Deep-Sea biota: bacteria, meta- zoan meiofauna, macrofauna and megafauna. The community standing stock decreases with depth; this is a universal phenomenon that involves a com- plex transition in the relative importance of the different size groups. Bacterial abundance and biomass show no decline with depth. All 3 animal size groups experience significant exponential de- creases in both abundance and biomass. The abun- dance of larger animals is significantly lower and decreases more rapidly than for smaller groups. The resulting drop in average body size with depth con- firms Thiel's size-structure hypothesis on very large spatial scales. In terms of their proportion of total community biomass, smaller size classes replace larger size classes. The upper continental slope is dominated by macrofaunal biomass, and the abyss by bacterial and meiofaunal biomass. The dramatic decrease in total community standing stock and the ascendancy of smaller organisms with depth has important implications for Deep-Sea biodiversity. The bathyal zone (200 to 4000 m) affords more eco- logical and evolutionary opportunity in the form of energy availability for larger organisms, and conse- quently supports higher macrofaunal and mega- faunal species diversity than the abyss (> 4000 m).
-
A Source‐Sink Hypothesis for Abyssal Biodiversity
The American naturalist, 2004Co-Authors: Michael A. Rex, Ron J. Etter, Craig R. Mcclain, John A. Allen, Nicholas A. Johnson, Philippe Bouchet, Anders WarénAbstract:Abstract: Bathymetric gradients of biodiversity in the deep‐sea Benthos constitute a major class of large‐scale biogeographic phenomena. They are typically portrayed and interpreted as variation in α diversity (the number of species recovered in individual samples) along depth transects. Here, we examine the depth ranges of deep‐sea gastropods and bivalves in the eastern and western North Atlantic. This approach shows that the abyssal molluscan fauna largely represents deeper range extensions for a subset of bathyal species. Most abyssal species have larval dispersal, and adults live at densities that appear to be too low for successful reproduction. These patterns suggest a new explanation for abyssal biodiversity. For many species, bathyal and abyssal populations may form a source‐sink system in which abyssal populations are regulated by a balance between chronic extinction arising from vulnerabilities to Allee effects and immigration from bathyal sources. An increased significance of source‐sink dynami...
-
Latitudinal gradients of species richness in the Deep-Sea Benthos of the North Atlantic
Proceedings of the National Academy of Sciences of the United States of America, 2000Co-Authors: Michael A. Rex, Carol T. Stuart, Gina CoyneAbstract:Latitudinal species diversity gradients (LSDGs) in the Northern Hemisphere are the most well established biogeographic patterns on Earth. Despite long-standing interest in LSDGs as a central problem in ecology, their explanation remains uncertain. In terrestrial as well as coastal and pelagic marine ecosystems, these poleward declines in diversity typically have been represented and interpreted in terms of species richness, the number of coexisting species. Newly discovered LSDGs in the bathyal (500–4,000 m) Benthos of the North Atlantic may help to resolve the underlying causes of these large-scale trends because the deep sea is such a physically distinct environment. However, a major problem in comparing surface and Deep-Sea LSDGs is that the latter have been measured differently, by using species diversity indices that are affected by both species richness and the evenness of relative abundance. Here, we demonstrate that Deep-Sea isopods, gastropods, and bivalves in the North Atlantic do exhibit poleward decreases in species richness, just as those found in other environments. A comprehensive systematic revision of the largest Deep-Sea gastropod family (Turridae) has provided a unique database on geographic distributions that is directly comparable to those used to document LSDGs in surface biotas. This taxon also shows a poleward decline in the number of species. Seasonal organic enrichment from sinking phytodetritus is the most plausible ecological explanation for Deep-Sea LSDGs and is the environmental factor most consistently associated with depressed diversity in a variety of bathyal habitats.
-
Bathymetric patterns of genetic variation in a Deep-Sea protobranch bivalve, Deminucula atacellana
Marine Biology, 1998Co-Authors: Michael R. Chase, Ron J. Etter, Michael A. Rex, Joseph M. QuattroAbstract:The origin of the Deep-Sea benthic fauna is poorly understood and represents an enormous gap in our understanding of basic evolutionary phenomena. One obstacle to studying evolutionary patterns in the deep sea has been the technical difficulty of measuring genetic variation in species that are typically minute, rare, and must be recovered from extreme depths. We used molecular genetic techniques to quantify variation in the 16S rRNA mitochondrial gene within and among populations of the common protobranch bivalve Deminucula atacellana (Schenck, 1939). We analyzed 89 individuals from nine samples collected in the 1960s along a depth gradient from 1100 to 3800 m in the western North Atlantic. Genetic variability within populations is much lower than between populations, and peak haplotype numbers occur near the center of its depth distribution. Continental slope ( 2500 m) populations were genetically distinct despite the lack of any obvious topographic or oceanographic features that would impede gene flow. These findings indicate that the Deep-Sea macrofauna can have strong population structure over small (134 km) spatial scales, similar to that observed in shallow-water and terrestrial organisms. This surprisingly high biodiversity at the genetic level affords the potential for adaptation and evolutionary diversification, the ultimate historical causes of high species diversity in the Deep-Sea Benthos.
Craig R. Mcclain - One of the best experts on this subject based on the ideXlab platform.
-
Metabolic Niches and Biodiversity: A Test Case in the Deep Sea Benthos
Frontiers in Marine Science, 2020Co-Authors: Craig R. Mcclain, Thomas J. Webb, Clifton C. Nunnally, S. River Dixon, Seth Finnegan, James A. NelsonAbstract:The great anthropogenic alterations occurring to carbon availability in the oceans necessitates an understanding of the energy requirements of species and how changes in energy availability may impact biodiversity. The deep oceans are characterized naturally by extremely low availability of chemical energy and are particularly vulnerable to changes in carbon flux from surface waters. Because the energetic requirements of an organism impact nearly every aspect of their ecology and evolution, we hypothesize that species are adapted to specific levels of carbon availability and occupy a particular metabolic niche. We test this hypothesis in Deep-Sea invertebrates specifically examining how energetic demand, axes of the metabolic niche, and geographic range size vary over gradients of chemical energy availability. We find that species with higher energetic expenditures, and ecologies associated with high energy demand, are located in areas with higher chemical energy availability. In addition, we find that range size and location of Deep-Sea species is determined by geographic patterns in chemical energy availability. Our findings indicate that Deep-Sea species are adapted to specific energy regimes, the metabolic niche can potentially link scales from individuals to ecosystems, and link adaptation to patterns in biogeography and biodiversity.
-
Alligators in the abyss: The first experimental reptilian food fall in the deep ocean.
PloS one, 2019Co-Authors: Craig R. Mcclain, Clifton C. Nunnally, River Dixon, Greg W. Rouse, Mark C. BenfieldAbstract:The high respiration rates of the Deep-Sea Benthos cannot be sustained by known carbon supply pathways alone. Here, we investigate moderately-sized reptilian food falls as a potential alternative carbon pathway. Specifically, three individual carcasses of Alligator mississippiensis were deployed along the continental slope of the northern Gulf of Mexico at depths of ~2000m in early 2019. We posit the tough hide of alligators would impeded scavengers by limiting access to soft tissues of the alligator fall. However, the scavengers began consuming the food fall 43 hours post-deployment for one individual (198.2cm, 29.7kg), and the carcass of another individual (175.3 cm, 19.5kg) was completely devoid of soft tissue at 51 days post-deployment. A third individual (172.7cm, 18.5kg) was missing completely after 8 days, with only the deployment harness and weight remaining drug 8 meters away, suggesting a large elasmobranch scavenger. Additionally, bones recovered post-deployment reveal the first observations of the bone-eating Osedax in the Gulf of Mexico and are confirmed here as new to science. The findings of this study indicate the quick and successful utilization of terrestrial and aquatic-based carbon food sources in the deep marine environment, though outcome variability may be high.
-
Toward a Conceptual Understanding of β-Diversity in the Deep-Sea Benthos
Annual Review of Ecology Evolution and Systematics, 2015Co-Authors: Craig R. Mcclain, Michael A. RexAbstract:We review patterns and causes of β-diversity in the Deep-Sea Benthos at different spatial scales and for different body sizes. Changes in species composition occurring with depth are generally gradual, the rate of change being a function of the rate of descent. This gradual change can be interrupted by abrupt environmental shifts, such as oxygen minimum zones, and by major topographic features that alter oceanographic conditions. Changes in species composition with depth can involve both species replacement and species loss, leading to nestedness. Horizontal β-diversity is more moderate than that occurring with depth, except at upper bathyal zones impacted by coastal influences. At very large oceanic scales, both environmental filtering and dispersal limitation influence β-diversity. Although many ecological and evolutionary–historical factors must shape β-diversity in the deep sea, energy availability appears to structure community makeup at all scales examined. We recommend that standardized sampling pr...
-
On some hypotheses of diversity of animal life at great depths on the sea floor
Marine Ecology, 2015Co-Authors: Craig R. Mcclain, Thomas A. SchlacherAbstract:Multiple hypotheses have emerged to explain the apparent paradox of high diversity of the Deep-Sea Benthos when the environmental conditions are often predicted to inhibit rather than promote diversity. Many fundamental facets of these paradigms remain incompletely understood despite being central to understanding how Deep-Sea ecosystems, and more generally all ecosystems, function. Here, we examine nine major paradigms of Deep-Sea diversity that deserve, in our opinion, a fresh research impetus. We purposely challenge many of these ideas to generate dialogue and encourage further research. Some of the axiomatic predictions of these paradigms are: (i) the deep sea is highly diverse; (ii) stable environments reduce competition; (iii) species have finely partitioned niches; (iv) biological cropping promotes diversity; (v) disturbance controls diversity; (vi) patch mosaics structure assemblages; (vii) productivity controls diversity; (viii) recovery from disturbance is slow; and (ix) the deep sea is notoriously under-sampled. We critically examine the evidence for each of these predictions and highlight areas where knowledge gaps exist and linkages to general ecological theory should occur. We conclude each section with ideas about questions and hypotheses that may fruitfully be tackled in future projects.
-
Local-scale faunal turnover on the deep Pacific seafloor
Marine Ecology Progress Series, 2011Co-Authors: Craig R. Mcclain, Jeffrey C. Nekola, Linda A. Kuhnz, James P BarryAbstract:The high biodiversity of the Deep-Sea floor is often attributed to high local coexistence of species achieved through microhabitat variation. Grassle & Sanders (1973; Deep-Sea Res 34: 313-341) proposed that Deep-Sea species were differentially adapted to multiple and small-scale suc- cessional patches that varied across the landscape and through time. However, results from both manipulative experiments and precision sampling to test the patch-mosaic model of Grassle & Sanders (1973) have varied, leading some authors to suggest that patch dynamics may be unimpor- tant in explaining Deep-Sea biodiversity. We utilized a remotely operated vehicle and a rigid spatial sampling protocol to document macrofaunal turnover and individual species spatial dispersion at a 3203 m deep site in the Pacific Ocean over scales of 1 to 350 m. We found high variability in assem- blage composition and, in contrast to most previous work, we also found that intraspecific species aggregation was common. These findings suggest that patch dynamics and microhabitat variation are important in promoting local species coexistence in the Deep-Sea Benthos.
Ron J. Etter - One of the best experts on this subject based on the ideXlab platform.
-
Global bathymetric patterns of standing stock and body size in the Deep-Sea Benthos
Marine Ecology Progress Series, 2006Co-Authors: Michael A. Rex, Ron J. Etter, Craig R. Mcclain, Jody W. Deming, Carol T. Stuart, Jeremy S. Morris, Jenifer Crouse, Nicholas A. Johnson, Rebecca Thies, Renee AveryAbstract:We present the first global-scale analy- sis of standing stock (abundance and biomass) for 4 major size classes of Deep-Sea biota: bacteria, meta- zoan meiofauna, macrofauna and megafauna. The community standing stock decreases with depth; this is a universal phenomenon that involves a com- plex transition in the relative importance of the different size groups. Bacterial abundance and biomass show no decline with depth. All 3 animal size groups experience significant exponential de- creases in both abundance and biomass. The abun- dance of larger animals is significantly lower and decreases more rapidly than for smaller groups. The resulting drop in average body size with depth con- firms Thiel's size-structure hypothesis on very large spatial scales. In terms of their proportion of total community biomass, smaller size classes replace larger size classes. The upper continental slope is dominated by macrofaunal biomass, and the abyss by bacterial and meiofaunal biomass. The dramatic decrease in total community standing stock and the ascendancy of smaller organisms with depth has important implications for Deep-Sea biodiversity. The bathyal zone (200 to 4000 m) affords more eco- logical and evolutionary opportunity in the form of energy availability for larger organisms, and conse- quently supports higher macrofaunal and mega- faunal species diversity than the abyss (> 4000 m).
-
Mid-domain models as predictors of species diversity patterns: bathymetric diversity gradients in the deep sea
Oikos, 2005Co-Authors: Craig R. Mcclain, Ron J. EtterAbstract:Geometric constraints represent a class of null models that describe how species diversity may vary between hard boundaries that limit geographic distributions. Recent studies have suggested that a number of large scale biogeographic patterns of diversity (e.g. latitude, altitude, depth) may reflect boundary constraints. However, few studies have rigorously tested the degree to which mid-domain null predictions match empirical patterns or how sensitive the null models are to various assumptions. We explore how variation in the assumptions of these models alter null depth ranges and consequently bathymetric variation in diversity, and test the extent to which bathymetric patterns of species diversity in deep sea gastropods, bivalves, and polychaetes match null predictions based on geometric constraints. Range–size distributions and geographic patterns of diversity produced by these null models are sensitive to the relative position of the hard boundaries, the specific algorithms used to generate range sizes, and whether species are continuously or patchily distributed between range end points. How well empirical patterns support null expectations is highly dependent on these assumptions. Bathymetric patterns of species diversity for gastropods, bivalves and polychaetes differ substantially from null expectations suggesting that geometric constraints do not account for diversity–depth patterns in the deep sea Benthos.
-
A Source‐Sink Hypothesis for Abyssal Biodiversity
The American naturalist, 2004Co-Authors: Michael A. Rex, Ron J. Etter, Craig R. Mcclain, John A. Allen, Nicholas A. Johnson, Philippe Bouchet, Anders WarénAbstract:Abstract: Bathymetric gradients of biodiversity in the deep‐sea Benthos constitute a major class of large‐scale biogeographic phenomena. They are typically portrayed and interpreted as variation in α diversity (the number of species recovered in individual samples) along depth transects. Here, we examine the depth ranges of deep‐sea gastropods and bivalves in the eastern and western North Atlantic. This approach shows that the abyssal molluscan fauna largely represents deeper range extensions for a subset of bathyal species. Most abyssal species have larval dispersal, and adults live at densities that appear to be too low for successful reproduction. These patterns suggest a new explanation for abyssal biodiversity. For many species, bathyal and abyssal populations may form a source‐sink system in which abyssal populations are regulated by a balance between chronic extinction arising from vulnerabilities to Allee effects and immigration from bathyal sources. An increased significance of source‐sink dynami...
-
Bathymetric patterns of genetic variation in a Deep-Sea protobranch bivalve, Deminucula atacellana
Marine Biology, 1998Co-Authors: Michael R. Chase, Ron J. Etter, Michael A. Rex, Joseph M. QuattroAbstract:The origin of the Deep-Sea benthic fauna is poorly understood and represents an enormous gap in our understanding of basic evolutionary phenomena. One obstacle to studying evolutionary patterns in the deep sea has been the technical difficulty of measuring genetic variation in species that are typically minute, rare, and must be recovered from extreme depths. We used molecular genetic techniques to quantify variation in the 16S rRNA mitochondrial gene within and among populations of the common protobranch bivalve Deminucula atacellana (Schenck, 1939). We analyzed 89 individuals from nine samples collected in the 1960s along a depth gradient from 1100 to 3800 m in the western North Atlantic. Genetic variability within populations is much lower than between populations, and peak haplotype numbers occur near the center of its depth distribution. Continental slope ( 2500 m) populations were genetically distinct despite the lack of any obvious topographic or oceanographic features that would impede gene flow. These findings indicate that the Deep-Sea macrofauna can have strong population structure over small (134 km) spatial scales, similar to that observed in shallow-water and terrestrial organisms. This surprisingly high biodiversity at the genetic level affords the potential for adaptation and evolutionary diversification, the ultimate historical causes of high species diversity in the Deep-Sea Benthos.
-
Bathymetric patterns of body size: implications for Deep-Sea biodiversity
Deep Sea Research Part II: Topical Studies in Oceanography, 1998Co-Authors: Michael A. Rex, Ron J. EtterAbstract:Abstract The evolution of body size is a problem of fundamental interest, and one that has an important bearing on community structure and conservation of biodiversity. The most obvious and pervasive characteristic of the Deep-Sea Benthos is the small size of most species. The numerous attempts to document and explain geographic patterns of body size in the Deep-Sea Benthos have focused on variation among species or whole faunal components, and have led to conflicting and contradictory results. It is important to recognize that studying size as an adaptation to the Deep-Sea environment should include analyses within species using measures of size that are standardized to common growth stages. An analysis within eight species of Deep-Sea benthic gastropods presented here reveals a clear trend for size to increase with depth in both larval and adult shells. An ANCOVA with multiple comparison tests showed that, in general, size–depth relationships for both adult and larval shells are more pronounced in the bathyal region than in the abyss. This result reinforces the notion that steepness of the bathymetric selective gradient decreases with depth, and that the bathyal region is an evolutionary hotspot that promotes diversification. Bathymetric size clines in gastropods support neither the predictions of optimality models nor earlier arguments based on tradeoffs among scaling factors. As in other environments, body size is inversely related to both abundance and species density. We suggest that the decrease in nutrient input with depth may select for larger size because of its metabolic or competitive advantages, and that larger size plays a role in limiting diversity. Adaptation is an important evolutionary driving force of biological diversity, and geographic patterns of body size could help unify ecological and historical theories of Deep-Sea biodiversity.
Sönke Johnsen - One of the best experts on this subject based on the ideXlab platform.
-
Light and Vision in the Deep-Sea Benthos
Frontiers in Physiology, 2013Co-Authors: Tamara M. Frank, Sönke JohnsenAbstract:Using new collecting techniques with the Johnson-Sea-Link submersible, eight species of Deep-Sea benthic crustaceans were collected with intact visual systems. Their spectral sensitivities and temporal resolutions were determined shipboard using electroretinography. Useable spectral sensitivity data were obtained from seven species, and in the dark-adapted eyes, the spectral sensitivity peaks were in the blue region of the visible spectrum, ranging from 470 to 497 nm. Under blue chromatic adaptation, a secondary sensitivity peak in the UV portion of the spectrum appeared for two species of anomuran crabs: Eumunida picta (lambda max = 363 nm) and Gastroptychus spinifer (lambda max = 383 nm). Wavelength-specific differences in response waveforms under blue chromatic adaptation in these two species suggest that two populations of photoreceptor cells are present. Temporal resolution was determined in all eight species using the maximum critical flicker frequency (CFFmax). The CFFmax for the isopod Booralana tricarinata of 4 Hz proved to be the lowest ever measured using this technique, and suggests that this species is not able to track even slow-moving prey. Both the putative dual visual pigment system in the crabs and the extremely slow eye of the isopod may be adaptations for seeing bioluminescence in the Deep-Sea benthic environment, which spectral measurements and in situ video showed to be a combination of greener bioluminescence from sessile benthic species superimposed with bluer bioluminescence emitted by planktonic organisms as they impacted the habitat
-
Light and vision in the Deep-Sea Benthos: I. Bioluminescence at 500-1000 m depth in the Bahamian islands.
The Journal of experimental biology, 2012Co-Authors: Sönke Johnsen, Tamara M. Frank, Steven H. D. Haddock, Edith A. Widder, Charles G. MessingAbstract:Bioluminescence is common and well studied in mesopelagic species. However, the extent of bioluminescence in benthic sites of similar depths is far less studied, although the relatively large eyes of benthic fish, crustaceans and cephalopods at bathyal depths suggest the presence of significant biogenic light. Using the Johnson-Sea-Link submersible, we collected numerous species of cnidarians, echinoderms, crustaceans, cephalopods and sponges, as well as one annelid from three sites in the northern Bahamas (500-1000 m depth). Using mechanical and chemical stimulation, we tested the collected species for light emission, and photographed and measured the spectra of the emitted light. In addition, in situ intensified video and still photos were taken of different benthic habitats. Surprisingly, bioluminescence in benthic animals at these sites was far less common than in mesopelagic animals from similar depths, with less than 20% of the collected species emitting light. Bioluminescent taxa comprised two species of anemone (Actinaria), a new genus and species of flabellate Parazoanthidae (formerly Gerardia sp.) (Zoanthidea), three sea pens (Pennatulacea), three bamboo corals (Alcyonacea), the chrysogorgiid coral Chrysogorgia desbonni (Alcyonacea), the caridean shrimp Parapandalus sp. and Heterocarpus ensifer (Decapoda), two holothuroids (Elasipodida and Aspidochirota) and the ophiuroid Ophiochiton ternispinus (Ophiurida). Except for the ophiuroid and the two shrimp, which emitted blue light (peak wavelengths 470 and 455 nm), all the species produced greener light than that measured in most mesopelagic taxa, with the emissions of the pennatulaceans being strongly shifted towards longer wavelengths. In situ observations suggested that bioluminescence associated with these sites was due primarily to light emitted by bioluminescent planktonic species as they struck filter feeders that extended into the water column.
-
Light and vision in the Deep-Sea Benthos: II. Vision in Deep-Sea crustaceans
Journal of Experimental Biology, 2012Co-Authors: Tamara M. Frank, Sönke Johnsen, Thomas W. CroninAbstract:SUMMARY Using new collecting techniques with the Johnson-Sea-Link submersible, eight species of Deep-Sea benthic crustaceans were collected with intact visual systems. Their spectral sensitivities and temporal resolutions were determined shipboard using electroretinography. Useable spectral sensitivity data were obtained from seven species, and in the dark-adapted eyes, the spectral sensitivity peaks were in the blue region of the visible spectrum, ranging from 470 to 497 nm. Under blue chromatic adaptation, a secondary sensitivity peak in the UV portion of the spectrum appeared for two species of anomuran crabs: Eumunida picta (λ max 363 nm) and Gastroptychus spinifer (λ max 383 nm). Wavelength-specific differences in response waveforms under blue chromatic adaptation in these two species suggest that two populations of photoreceptor cells are present. Temporal resolution was determined in all eight species using the maximum critical flicker frequency (CFF max ). The CFF max for the isopod Booralana tricarinata of 4 Hz proved to be the lowest ever measured using this technique, and suggests that this species is not able to track even slow-moving prey. Both the putative dual visual pigment system in the crabs and the extremely slow eye of the isopod may be adaptations for seeing bioluminescence in the benthic environment.
-
Light and vision in the Deep-Sea Benthos: I. Bioluminescence at 500–1000 m depth in the Bahamian Islands
Journal of Experimental Biology, 2012Co-Authors: Sönke Johnsen, Tamara M. Frank, Steven H. D. Haddock, Edith A. Widder, Charles G. MessingAbstract:Bioluminescence is common and well studied in mesopelagic species. However, the extent of bioluminescence in benthic sites of similar depths is far less studied, although the relatively large eyes of benthic fish, crustaceans and cephalopods at bathyal depths suggest the presence of significant biogenic light. Using the Johnson-Sea-Link submersible, we collected numerous species of cnidarians, echinoderms, crustaceans, cephalopods and sponges, as well as one annelid from three sites in the northern Bahamas (500–1000 m depth). Using mechanical and chemical stimulation, we tested the collected species for light emission, and photographed and measured the spectra of the emitted light. In addition, in situ intensified video and still photos were taken of different benthic habitats. Surprisingly, bioluminescence in benthic animals at these sites was far less common than in mesopelagic animals from similar depths, with less than 20% of the collected species emitting light. Bioluminescent taxa comprised two species of anemone (Actinaria), a new genus and species of flabellate Parazoanthidae (formerly Gerardia sp.) (Zoanthidea), three sea pens (Pennatulacea), three bamboo corals (Alcyonacea), the chrysogorgiid coral Chrysogorgia desbonni (Alcyonacea), the caridean shrimp Parapandalus sp. and Heterocarpus ensifer (Decapoda), two holothuroids (Elasipodida and Aspidochirota) and the ophiuroid Ophiochiton ternispinus (Ophiurida). Except for the ophiuroid and the two shrimp, which emitted blue light (peak wavelengths 470 and 455 nm), all the species produced greener light than that measured in most mesopelagic taxa, with the emissions of the pennatulaceans being strongly shifted towards longer wavelengths. In situ observations suggested that bioluminescence associated with these sites was due primarily to light emitted by bioluminescent planktonic species as they struck filter feeders that extended into the water column.
-
RESEARCH ARTICLE Light and vision in the Deep-Sea Benthos: II. Vision in Deep-Sea crustaceans
2012Co-Authors: Tamara M. Frank, Sönke Johnsen, Thomas W. CroninAbstract:SUMMARY Using new collecting techniques with the Johnson-Sea-Link submersible, eight species of Deep-Sea benthic crustaceans were collected with intact visual systems. Their spectral sensitivities and temporal resolutions were determined shipboard using electroretinography. Useable spectral sensitivity data were obtained from seven species, and in the dark-adapted eyes, the spectral sensitivity peaks were in the blue region of the visible spectrum, ranging from 470 to 497nm. Under blue chromatic adaptation, a secondary sensitivity peak in the UV portion of the spectrum appeared for two species of anomuran crabs: Eumunida picta (max363nm) and Gastroptychus spinifer (max383nm). Wavelength-specific differences in response waveforms under blue chromatic adaptation in these two species suggest that two populations of photoreceptor cells are present. Temporal resolution was determined in all eight species using the maximum critical flicker frequency (CFFmax). The CFFmax for the isopod Booralana tricarinata of 4Hz proved to be the lowest ever measured using this technique, and suggests that this species is not able to track even slow-moving prey. Both the putative dual visual pigment system in the crabs and the extremely slow eye of the isopod may be adaptations for seeing bioluminescence in the benthic environment.
Tamara M. Frank - One of the best experts on this subject based on the ideXlab platform.
-
Light and Vision in the Deep-Sea Benthos
Frontiers in Physiology, 2013Co-Authors: Tamara M. Frank, Sönke JohnsenAbstract:Using new collecting techniques with the Johnson-Sea-Link submersible, eight species of Deep-Sea benthic crustaceans were collected with intact visual systems. Their spectral sensitivities and temporal resolutions were determined shipboard using electroretinography. Useable spectral sensitivity data were obtained from seven species, and in the dark-adapted eyes, the spectral sensitivity peaks were in the blue region of the visible spectrum, ranging from 470 to 497 nm. Under blue chromatic adaptation, a secondary sensitivity peak in the UV portion of the spectrum appeared for two species of anomuran crabs: Eumunida picta (lambda max = 363 nm) and Gastroptychus spinifer (lambda max = 383 nm). Wavelength-specific differences in response waveforms under blue chromatic adaptation in these two species suggest that two populations of photoreceptor cells are present. Temporal resolution was determined in all eight species using the maximum critical flicker frequency (CFFmax). The CFFmax for the isopod Booralana tricarinata of 4 Hz proved to be the lowest ever measured using this technique, and suggests that this species is not able to track even slow-moving prey. Both the putative dual visual pigment system in the crabs and the extremely slow eye of the isopod may be adaptations for seeing bioluminescence in the Deep-Sea benthic environment, which spectral measurements and in situ video showed to be a combination of greener bioluminescence from sessile benthic species superimposed with bluer bioluminescence emitted by planktonic organisms as they impacted the habitat
-
Light and vision in the Deep-Sea Benthos: I. Bioluminescence at 500-1000 m depth in the Bahamian islands.
The Journal of experimental biology, 2012Co-Authors: Sönke Johnsen, Tamara M. Frank, Steven H. D. Haddock, Edith A. Widder, Charles G. MessingAbstract:Bioluminescence is common and well studied in mesopelagic species. However, the extent of bioluminescence in benthic sites of similar depths is far less studied, although the relatively large eyes of benthic fish, crustaceans and cephalopods at bathyal depths suggest the presence of significant biogenic light. Using the Johnson-Sea-Link submersible, we collected numerous species of cnidarians, echinoderms, crustaceans, cephalopods and sponges, as well as one annelid from three sites in the northern Bahamas (500-1000 m depth). Using mechanical and chemical stimulation, we tested the collected species for light emission, and photographed and measured the spectra of the emitted light. In addition, in situ intensified video and still photos were taken of different benthic habitats. Surprisingly, bioluminescence in benthic animals at these sites was far less common than in mesopelagic animals from similar depths, with less than 20% of the collected species emitting light. Bioluminescent taxa comprised two species of anemone (Actinaria), a new genus and species of flabellate Parazoanthidae (formerly Gerardia sp.) (Zoanthidea), three sea pens (Pennatulacea), three bamboo corals (Alcyonacea), the chrysogorgiid coral Chrysogorgia desbonni (Alcyonacea), the caridean shrimp Parapandalus sp. and Heterocarpus ensifer (Decapoda), two holothuroids (Elasipodida and Aspidochirota) and the ophiuroid Ophiochiton ternispinus (Ophiurida). Except for the ophiuroid and the two shrimp, which emitted blue light (peak wavelengths 470 and 455 nm), all the species produced greener light than that measured in most mesopelagic taxa, with the emissions of the pennatulaceans being strongly shifted towards longer wavelengths. In situ observations suggested that bioluminescence associated with these sites was due primarily to light emitted by bioluminescent planktonic species as they struck filter feeders that extended into the water column.
-
Light and vision in the Deep-Sea Benthos: II. Vision in Deep-Sea crustaceans
Journal of Experimental Biology, 2012Co-Authors: Tamara M. Frank, Sönke Johnsen, Thomas W. CroninAbstract:SUMMARY Using new collecting techniques with the Johnson-Sea-Link submersible, eight species of Deep-Sea benthic crustaceans were collected with intact visual systems. Their spectral sensitivities and temporal resolutions were determined shipboard using electroretinography. Useable spectral sensitivity data were obtained from seven species, and in the dark-adapted eyes, the spectral sensitivity peaks were in the blue region of the visible spectrum, ranging from 470 to 497 nm. Under blue chromatic adaptation, a secondary sensitivity peak in the UV portion of the spectrum appeared for two species of anomuran crabs: Eumunida picta (λ max 363 nm) and Gastroptychus spinifer (λ max 383 nm). Wavelength-specific differences in response waveforms under blue chromatic adaptation in these two species suggest that two populations of photoreceptor cells are present. Temporal resolution was determined in all eight species using the maximum critical flicker frequency (CFF max ). The CFF max for the isopod Booralana tricarinata of 4 Hz proved to be the lowest ever measured using this technique, and suggests that this species is not able to track even slow-moving prey. Both the putative dual visual pigment system in the crabs and the extremely slow eye of the isopod may be adaptations for seeing bioluminescence in the benthic environment.
-
Light and vision in the Deep-Sea Benthos: I. Bioluminescence at 500–1000 m depth in the Bahamian Islands
Journal of Experimental Biology, 2012Co-Authors: Sönke Johnsen, Tamara M. Frank, Steven H. D. Haddock, Edith A. Widder, Charles G. MessingAbstract:Bioluminescence is common and well studied in mesopelagic species. However, the extent of bioluminescence in benthic sites of similar depths is far less studied, although the relatively large eyes of benthic fish, crustaceans and cephalopods at bathyal depths suggest the presence of significant biogenic light. Using the Johnson-Sea-Link submersible, we collected numerous species of cnidarians, echinoderms, crustaceans, cephalopods and sponges, as well as one annelid from three sites in the northern Bahamas (500–1000 m depth). Using mechanical and chemical stimulation, we tested the collected species for light emission, and photographed and measured the spectra of the emitted light. In addition, in situ intensified video and still photos were taken of different benthic habitats. Surprisingly, bioluminescence in benthic animals at these sites was far less common than in mesopelagic animals from similar depths, with less than 20% of the collected species emitting light. Bioluminescent taxa comprised two species of anemone (Actinaria), a new genus and species of flabellate Parazoanthidae (formerly Gerardia sp.) (Zoanthidea), three sea pens (Pennatulacea), three bamboo corals (Alcyonacea), the chrysogorgiid coral Chrysogorgia desbonni (Alcyonacea), the caridean shrimp Parapandalus sp. and Heterocarpus ensifer (Decapoda), two holothuroids (Elasipodida and Aspidochirota) and the ophiuroid Ophiochiton ternispinus (Ophiurida). Except for the ophiuroid and the two shrimp, which emitted blue light (peak wavelengths 470 and 455 nm), all the species produced greener light than that measured in most mesopelagic taxa, with the emissions of the pennatulaceans being strongly shifted towards longer wavelengths. In situ observations suggested that bioluminescence associated with these sites was due primarily to light emitted by bioluminescent planktonic species as they struck filter feeders that extended into the water column.
-
RESEARCH ARTICLE Light and vision in the Deep-Sea Benthos: II. Vision in Deep-Sea crustaceans
2012Co-Authors: Tamara M. Frank, Sönke Johnsen, Thomas W. CroninAbstract:SUMMARY Using new collecting techniques with the Johnson-Sea-Link submersible, eight species of Deep-Sea benthic crustaceans were collected with intact visual systems. Their spectral sensitivities and temporal resolutions were determined shipboard using electroretinography. Useable spectral sensitivity data were obtained from seven species, and in the dark-adapted eyes, the spectral sensitivity peaks were in the blue region of the visible spectrum, ranging from 470 to 497nm. Under blue chromatic adaptation, a secondary sensitivity peak in the UV portion of the spectrum appeared for two species of anomuran crabs: Eumunida picta (max363nm) and Gastroptychus spinifer (max383nm). Wavelength-specific differences in response waveforms under blue chromatic adaptation in these two species suggest that two populations of photoreceptor cells are present. Temporal resolution was determined in all eight species using the maximum critical flicker frequency (CFFmax). The CFFmax for the isopod Booralana tricarinata of 4Hz proved to be the lowest ever measured using this technique, and suggests that this species is not able to track even slow-moving prey. Both the putative dual visual pigment system in the crabs and the extremely slow eye of the isopod may be adaptations for seeing bioluminescence in the benthic environment.
