Download - The ocean is not deep enough
![Page 1: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/1.jpg)
THE OCEAN IS NOT DEEP ENOUGH
Pressure tolerance of Mytilus edulis early life stages
![Page 2: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/2.jpg)
![Page 3: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/3.jpg)
Major Question
How were deep sea environments colonized?
• High pressure environment• Noxious environment• Temperature extremes
![Page 4: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/4.jpg)
Le Chatelier’s Principle
Background
“If a chemical system at equilibrium experiences a change in concentration, temperature, volume or total pressure, the equilibrium will shift in order to counteract the imposed change” (Mestre et al. 2009)
![Page 5: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/5.jpg)
Pressure
Effects biochemical reactions and membrane functionality• Keq = [C][D]/[A][B], G = -RTlnKeq and v = k[s]
• P sensitivity of reactions: Kp = K1e(-PV/RT) and kp = k1e-PV‡/RT
• P therefore affects both Keq and k (Kinsey 2009)
• Increased pressure will move the equilibrium to the side with lowest volume
Limits depth range of marine organisms Pressure tolerances are different for different life stages
Some life stages are more suited for deep-sea colonization
![Page 6: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/6.jpg)
Along with pressure also plays an important role in biochemical reactionsCan speed up or slow down metabolism
Response also varies with life stage Can counteract pressure effects
If membrane is more compressed because of pressure can be somewhat decompressed by higher temperature
Temperature
![Page 7: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/7.jpg)
What would limit organisms to a depth and temperature range in early ontogeny?
![Page 8: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/8.jpg)
Biochemical reactions during fertilization
![Page 9: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/9.jpg)
Program for post-fertilization changes in egg of sea urchins
Epel 1975
![Page 10: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/10.jpg)
Ca-Wave After Fertilization
![Page 11: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/11.jpg)
Biochemical pathways are sensitive pathways Could organisms, like mussels, with
sensitive biochemical pathways colonize deep-sea habitat?
![Page 12: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/12.jpg)
How were deep sea environments colonized by
mussels?Mestre et al. chose a shallow-
water relative of a deep-sea inhabitant
![Page 13: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/13.jpg)
Phylogenetic Relationship
subfamilys Mytilinae and Bathymodiolinae
Shallow water species Mytilus edulis found here
The rest are associated with one of the following:
Hydrothermal ventCold-water seepWood/bone
(Kyuno et al. 2009)
![Page 14: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/14.jpg)
Free-spawning marine invertebrates
Worldwide distribution
Found in intertidal zones and estuaries
Endure a wide range of temperatures and physical challenges
Mytilus edulis
![Page 15: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/15.jpg)
Origin of deep-sea mussels 2 Hypotheses:
Deep sea species evolved from shallow-sea species in step-wise fashion via wood/bone habitat
Direct colonization via larval transport from shallow-sea to deep-sea habitats.
![Page 16: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/16.jpg)
Origin of deep-sea mussels 2 Hypotheses:
Deep sea species evolved from shallow-sea species in step-wise fashion via wood/bone habitat
Direct colonization via larval migration from shallow-sea to deep-sea habitats○ Determine larval functional tolerance of
pressure and temperature
![Page 17: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/17.jpg)
Methods 3 Experiments
Temperature effect on embryonic larvae and development
Pressure effect on embryonic larvae and development with fertilization under pressure
Pressure effect on embryonic larvae and development with fertilization at atmospheric pressure
![Page 18: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/18.jpg)
Staging criteria for larvae:
![Page 19: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/19.jpg)
Embryonic stages
D-larvae
Fertilized eggSixteen-cell
stage
Multi-cell stage
Early blastula
Two-cell stage
Four-cell stage
![Page 20: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/20.jpg)
Temperature effect on embryonic larvae and development 5 temperature treatments
5, 10, 15, 20, and 25C, at atmospheric pressure
Incubated until all treatments had reached D-larvae stage.
![Page 21: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/21.jpg)
Pressure Vesselsa) Plastic vial filled with the
egg suspension and the microcentrifuge tube hald-filled with sperm suspension
b) Pressure vessel showing the plastic vials inside
Figure 1 from Mestre et al. 2009
Pressure Experiments
![Page 22: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/22.jpg)
Pressure effect on embryonic and larvae development with fertilization under pressure Placed sperm in separate vial which ruptured at
pressure Resulting embryos were incubated at different
temperature/pressure treatments Pressure/Temperature treatments
Temperature treatments○ 10, 15, and 20C
Pressure treatments○ 1, 100, 200, and 300 atm ○ + 400 and 500atm for 4 hour treatments
○Incubated for 4 and 24 hours
![Page 23: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/23.jpg)
Pressure effect on embryonic and larval development with fertilization at atmospheric pressure Fertilization at atmospheric pressure, at
15C Resulting embryos were incubated at 4
different pressures and 5 different temperaturesTemperature treatments
○ 5, 10, 15, 20, and 25CPressure treatments
○ 1, 100, 200, and 300 atm Incubated for 50 hours
![Page 24: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/24.jpg)
Results Divided results from 3 methods into 2
categories:Temperature effects on embryonic and larval
developmentPressure effects on embryonic and larval
development
![Page 25: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/25.jpg)
Temperature effects on embryonic and larval development
Mytilus edulis embryos develop faster at higher temperatures
Effect in the proportion of abnormally developing embryos
![Page 26: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/26.jpg)
Pressure effects on embryonic and larval development with fertilization at atmospheric pressure after 50hrs
![Page 27: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/27.jpg)
Pressure effects with fertilization under pressure at 4 hours
![Page 28: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/28.jpg)
Pressure effects with fertilization under pressure at 24 hours
![Page 29: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/29.jpg)
Krustal-Wallis analysis of variance
![Page 30: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/30.jpg)
Conclusions Temperature tolerance window is from
approximately 10-20C Embryo development possible up to
500atm (~5000m)Hypothesized pressure presents no barrier to
fertilization Slower development with increasing
pressure Increase in abnormal cells with increasing
pressure due to membrane rupture
![Page 31: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/31.jpg)
“reasonable to hypothesize that the invasion of the deep sea by M. edulis is possible in terms of pressure tolerances in embryos and larvae
Was hypothesis correct?
![Page 32: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/32.jpg)
References Kyuno, Akiko; Shintaku, Mifue; Fujita, Yuko; Matsumoto,
Hiroto; Utsumi, Motoo; Watanabe, Hiromi; Fujiwara, Yoshihiro; Miyazaki, Jun-Ichi. 2009. Dispersal and Differentiation of Deep-Sea Mussels of the Genus Bathymodiolus (Mytilidae, Bathymodiolinae). Journal of Marine Biology. Vol. 2009. pp. 15.
Epel, David. 1975. The Program of and Mechanisms of Fertilization in the Echinoderm Egg. American Zoologist. 15, 3. pp. 507-522.
Mestre, Nelia C.; Thatje, Sven; Tyler, Paul A. 2009. The ocean is not deep enough: pressure tolerances during early ontogeny of the blue mussel Mytilus edulis. Proc. R. Soc. B 276, pp. 717-726.
![Page 33: The ocean is not deep enough](https://reader035.vdocuments.us/reader035/viewer/2022062302/5681671c550346895ddb9471/html5/thumbnails/33.jpg)
Discussion Questions What other effects of pressure could
cause developmental problems? Do their results support direct
colonization?Last section of discussion implies it does