Czechia

The vent crab (Xenograpsus testudinatus), a dominant species in shallow water hydrothermal vents of Kueishan Island (Taiwan) and the Northwest Pacific fire ring, exhibits no significant genetic differentiation among populations. The underlying physiological traits and behavioral adaptations facilitating its survival in these environments are yet to be elucidated. This study collected X. testudinatus from two physicochemically contrasting sites: Kueishan Island and Shōwa Iōjima (Japan), the latter characterized by higher CO2 levels but lacking sulfides. Hemolymph analysis revealed comparable glucose levels between populations, but higher lactate in Shōwa Iōjima crabs, suggesting elevated CO2 contributes to anaerobic metabolism. In Kueishan Island, hemolymphic lactate positively correlated with sulfide presence and negatively with alkalinity, indicating a significant association between sulfide concentrations, alkaline components, and the regulation of anaerobic metabolic processes in the organism. Re-acclimatization experiments demonstrated a rapid lactate increase upon sulfide reintroduction, suggesting the importance of anaerobic respiration in adaptation. Moreover, vent crabs exhibited no positive sulfide chemotaxis, with Kueishan Island crabs displaying negative chemotaxis, potentially avoiding highly toxic areas. This study reveals diverse metabolic traits and behavioral responses employed by X. testudinatus to thrive in distinct hydrothermal habitats, underscoring the importance of phenotypic plasticity in their success.

SEB Conference Prague 2024

Metabolic traits, chemotaxis, and environmental interactions of hydrothermal vent crab Xenograpsus testudinatus

adaptive plasticity

chemotaxis

sulfide effects

metabolic traits

hydrothermal vents

xenograpsus testudinatus

technical paper

If you see this page it means you are not logged in or registered.

If you  feel like you see this message by mistake please make sure you are logged in with the email you registered with.

If you are not registered yet you can do so [**here**](https://www.sebiology.org/events/seb-conference-prague-2024/registration2024.html). 

Please login or register

SEB’s Annual Conference is celebrated for creating the perfect composition of research, new discoveries and collaborative connections. Be creative and innovative by exchanging ideas and knowledge with masters of biology from all over the world.

Biotic interaction with complex communities of microbiota inhabiting every mucosal surface of teleost fish strongly influence the host metabolism, growth and health. The gill mucosal surface constitutes a special habitat for host-associated microbes due to its unique functions in waste excretion, gas exchange and local immune activity. The gill associated lymphoid tissue (GIALT) enables fish to discriminate between beneficial and pathogenic bacteria keeping microbiome homeostasis. Changes in the environment however, including water conditions, seasonal changes and physiological stress can lead to compositional disturbances that turn commensals into pathogens. This sensitivity to environmental parameters provides the opportunity to use the microbiome composition of the external mucus as a biomarker for the health of the fish. 
Here we compare the microbial gill mucus communities of the two teleost species Osmerus eperlanus and Gymnocephalus cernua from different life-history guilds and the bacterioplankton in the Elbe estuary. Over the course of one year, we collected 220 fish along the main channel of the estuary and generated matching 16S rRNA metabarcoding and host transcriptome libraries. The aim is to characterize the physiological response along spatio-temporal gradients, extract bacterial indicator species and determine driving factors for fish health.


Wild fish holobiont response to abiotic gradients in the Elbe estuary

Until recently, the role of mitochondria in migration physiology and energetics has been mostly unstudied. The migratory phenotype consists of whole-organism to subcellular adaptations although a paucity of information exists on how organelles within the cell may play a critical role. Our research has focused on two-study comparisons of closely related migrants and non-migrants, in the family Mimidae and genus Zonotrichia. Here, we discuss our mitochondrial respiratory performance results between our study groups by measuring mitochondrial respiration using High-resolution respirometry. Additionally, we discuss other important variables and measurements that were collected that allow us to examine oxygen carrying capacity, fuel usage, and whole-organism performance. Our initial study on migratory and non-migratory, White-crowned Sparrows (Zonotrichia leucophyrs), demonstrated evidence of seasonal upregulation of mitochondrial performance related to migration. However, our Mimidae results did not. We discuss potential explanations for these patterns and how we are currently working to understand the mechanisms underlying our results. Lastly, we discuss our current work on expanding to other Zonotrichia groups to control for relatedness in our study.

Measuring mitochondrial respiratory performance in closely related migrant and non-migrant avian species

The frequency of hypoxic events (i.e. decrease of dissolved oxygen level in water) is increasing at an unprecedented rate due to anthropogenic pollution and climate change. As species might not be able to adapt fast enough to this rapid change, they would need to rely on faster phenotypic responses such as plasticity. If the stressor becomes persistent, some transgenerational plasticity could occur. Physiologically the low oxygen environment can impact the organism's metabolism, potentially affecting their fitness. Therefore, more studies are needed to decipher fish metabolisms plasticity to hypoxia within and across generations. To investigate this, we did a multigenerational experiment with a wild population of Gasterosteus aculeatus. The first generation (F1) was either exposed to normoxia (100% dissolved oxygen, DO), or daily fluctuating hypoxia (30% DO at night and 100% DO during the day) mimicking the oxygen fluctuation happening in the wild. Their offspring (F2) were reared either matching their parental condition or not, resulting in four different groups reflecting within- or trans-generational plasticity. We assessed their aerobic metabolism (aerobic scope) and oxygen transport capacity (maximal heart rate frequency, blood hematocrit, and hemoglobin content) as well as the anaerobic metabolism (hypoxia tolerance and Pcrit). The results only showed within plasticity to fluctuating hypoxia with an increased hypoxia tolerance of the fish and decreased Pcrit, while the aerobic metabolism and oxygen transport capacity did not change. This study shows that fish might cope with this level of hypoxia through within-generation plasticity while transgenerational plasticity is not yet observed in measured traits.

Gasping for oxygen: The  cross-generational plasticity of  metabolism in Gasterosteus aculeatus exposed to fluctuating hypoxia

While hypoxia (i.e. low dissolved oxygen level in water) events occur naturally, global change and human activities have exacerbated their strength and temporal fluctuations. As populations may not be able to escape the hypoxic conditions, it is crucial to understand how organisms can adjust and adapt to these fluctuating environments across generations. When directly exposed, individuals may be able to adjust their phenotypes through plasticity to maintain their fitness. With continued exposure to hypoxia over generations, adaptive transgenerational plasticity can take place to help the offspring to survive the new conditions. Even longer exposure could also lead to the evolution of the population. However, so far, little is known on how plastic response to hypoxia could actually pave the way for future evolution. Using two populations of three-spined sticklebacks (Gasterosteus aculeatus) collected from streams already experiencing and potentially adapted to strong hypoxic events or not, we exposed the offspring to experimental hypoxia (30% air saturation during the night and 100% during the day) over three generations, resulting in several groups reflecting within-, inter-, and trans-generational plasticity, as well as adaptation. We then measured their growth, metabolism, and behaviour and highlighted that the plastic responses observed were not necessarily in line to the potential adaptation. While the directions of the responses were different, we cannot exclude that the fish plasticity might still be a strategy to cope with the environment until genetic adaptation occur.

Fish cross-generational response to hypoxia: can plasticity pave the way to evolution?

While the compliant skin of dolphin has long been believed to play a crucial role in reducing skin friction drag owing to its flexibility and sensitivity, most conventional studies have been focused on the static skin microstructure and the hydrodynamic pressured-excited passive deformation, which could not provide a convinced solution to the mystery of Gray’s paradox. In this study, inspired by microvibrations measured on dolphin skin, we hypothesize that a dynamically undulating skin surface actuated by the microvibrations enables effectively altering the turbulent boundary layer adjacent to the skin, resulting in decreasing the velocity fluctuations, thus in reducing skin-friction drag. We constructed an idealized model of open channel with a portion of the bottom wall undergoing the microvibrations and carried out a series of numerical simulations to investigate the characteristics of the boundary layer flow in terms of traveling and standing waves. We found that the microvibrations-excited skin/wall surface can create a reversed flow against or enhance the streamwise flow in the viscous sublayer of the boundary layer, substantially leading to a negative friction drag or a negative total drag, hence greatly reducing or even eliminating the drag to generate a thrust. The results reveal that a novel drag reduction mechanism can be achieved by means of the dolphin-inspired microvibrations, which thus may provide a highly plausible explanation for the long-standing mystery of the excellent hydrodynamic performance in dolphin swimming.

Can compliant skin vibration provide a novel drag reduction strategy in dolphin swimming?

Understanding predator-prey interactions is crucial in ecological research, with timing and kinematics of escape responses greatly affecting animal survival to predator attacks. However, little is known about the escape responses of elasmobranchs, or chondrichthyans. In this study, we investigated the escape responses in the spotted ratfish (Hydrolagus colliei), a smaller chondrichthyan predator found in the Puget Sound, to compare its ability to perform fast-start escape behaviour against other chondrichthyan species that inhabit the same region.  Previous work has found that adult ratfish possess Mauthner cells (M-cells), a key neural element associated with fast reactions in the escape responses of teleost fish and larval amphibians, though not known to be present in other adult chondrichthyans. Escape responses were elicited using mechanical stimuli for nine individuals, and videos were analysed to quantify response latencies, and turning angles and rates. Results indicated that ratfish do perform fast-start escape responses, with variations in response characteristics across individuals. The ratfish had a shorter minimum latency (36ms) when compared to the spiny dogfish (Squalus suckleyi) (66.7ms), an elasmobranch found in the Puget Sound that does not have M-cells. These findings contribute to our understanding of predator-prey dynamics in chondrichthyan species.

Escape response timing and kinematics in a deep-water chondrichthyan, the spotted ratfish, Hydrolagus colliei

Predator-prey relationships are an important factor shaping ecological communities. Functional response (FR) describes the relationship between the food resource density and amount of food consumed by a single predator and is commonly used to study the role of predator-prey interactions in population dynamics. Elevated temperature related to global change is likely to modify consumer-resource interactions. Another important factor is predator density, as hunting individuals can be positively or negatively influenced by nearby conspecifics. Higher energy expenditure in elevated temperature requires greater foraging activity (enhancing foraging efficiency), which in turn may increase the competitive pressure between multiple predators and lead to predator interference (reducing foraging efficiency). This underlies the need to include predator density as a factor affecting foraging efficiency when studying effects of rising temperatures. Here, we performed a laboratory experiment using three densities of a fish predator (pumpkinseed, Lepomis gibbosus) (1, 2 and 4 specimens), two temperatures (25 and 28 oC) and 6 prey densities. Using FR approach, we showed the effect of temperature on foraging efficiency of single and 2 predators, but not on foraging of a group of 4 predators. Moreover, increased conspecific presence strongly reduced predator efficiency at a lower temperature, whereas, at a higher temperature, conspecific effect was totally absent (2 individuals) or lower (4 individuals). Our study indicates that predator density is an important factor that should be considered in experiments on the effects of environmental change on foraging efficiency. This research was supported by National Science Centre, Poland (Grant No. 2020/39/D/NZ8/01226)

Interactive effects of density and elevated temperature on foraging efficiency of aquatic predator

Chill sensitive insects risk neuromuscular dysfunction in cold environments due to a mismatch between active and passive membrane ion transport. This is particularly critical for muscle cells function where hypothermic loss of Na+/K+-ATPase activity may cause depolarization due to loss of ion balance and decreased electrogenic polarization. To investigate this further we examined 10 Drosophila species with varying cold tolerances to quantify if chill-tolerant species defend membrane polarization better at low temperature through enhanced Na+-K+-ATPase activity. Muscle membrane potential measurements was measured in all species at 21°C and 0°C, with and without ouabain (a Na^+-K^+-ATPase blocker) . At benign temperature all species had similar muscle membrane potential of ~ -55 mV and in accordance with our hypothesis cold sensitive species exhibited a larger hypothermic depolarization. Further, measurements of membrane potential with ouabain showed that the cold induced depolarization in sensitive species was predominantly caused by a loss a Na+/K+ mediated electrogenic polarization. Subsequent measurements of whole animal standard metabolic rate at high and low temperature showed that the improved preservation of membrane in cold tolerant species came at a low cost as the more cold tolerant species were characterized by a lower mass specific metabolic rate despite the potential costs of maintained ion pumping in these cod adapted species.

Keep on pumping: Cold tolerant Drosophila resist hypothermic depolarization of muscle membrane potential

Tropical rainforest research was long the preserve of rich white men and the resulting literature was the same. This early bias in tropical research and publication may still be reflected in reading lists and recommended sources in higher education. We report on a study analysing the authorship of papers in the final year undergraduate option “Tropical Ecology” in SBOHVM University of Glasgow. The methodology utilised was that proposed by Bird and Pitman (2019) identifying gender, geography, and ethnicity of the authors. Nearly 79% of authors were male; 93.8% of authors whose ethnicity was identified were from non-BAME backgrounds; 80% of the authors were affiliated to institutes or universities in the global north. These results were reported to staff on the course with two outputs so far: reconsideration of the reading list and replacement of sources where possible; tutorial and discussion sessions with students taking the course to address the issues.


Decolonising the curriculum - a case study from Tropical Ecology

The consequences of climate change, such as soil salinization and droughts, are some of the main threats to agricultural production, environmental health, and economic welfare. Plant growth-promoting bacteria (PGPB) represent one nature-based solution to favour plant yield and growth in a changing environment. In our study, we explore the potentiality of Technosols to provide PGPBs with peculiar properties, including the capability to recover salt-affected soils and test the potentiality of Technosol-isolated PGPBs to enhance plant growth under saline conditions. For this purpose, selected Technosol-isolated PGPBs were mixed to produce two consortia, one of which was combined with an allochthonous halotolerant bacterium. Lettuce seeds were primed utilizing the two consortia and the saline bacterium alone. The experimental setup consisted of two steps. In the first one, seeds were primed with PGPBs and incubated on water agar media at different NaCl concentrations; in the second, seeds were incubated in not- and sterilized Technosol at different NaCl concentrations. Germination tests and biochemical analyses were performed to assess the potential benefits of PGPB symbiosis on plant growth performance. The water agar salinity test indicated an inhibitory effect of PGPBs on germination, while the use of saline-bacterium showed a positive response on seeds. Our study suggests that urban Technosols may provide PGPBs, whose features may be modified by allochthonous bacteria addition opening new perspectives in urban greening replacement, recovery of degraded environments, and urban soil microbiome ecology understanding.

Metabolic traits, chemotaxis, and environmental interactions of hydrothermal vent crab Xenograpsus testudinatus

Downloads

Next from SEB Conference Prague 2024

Wild fish holobiont response to abiotic gradients in the Elbe estuary

Stay up to date with the latest Underline news!

PRESENTATIONS

CONFERENCES

COMPANY

RESOURCES

Metabolic traits, chemotaxis, and environmental interactions of hydrothermal vent crab Xenograpsus testudinatus

.css-70qvj9{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;}Downloads

Next from SEB Conference Prague 2024

Wild fish holobiont response to abiotic gradients in the Elbe estuary

Stay up to date with the latest Underline news!

PRESENTATIONS

CONFERENCES

COMPANY

RESOURCES

Downloads