About Rob Grafton Expertise I can offer help up to UK degree level and have access to the national oceanographic library in Southampton. My speciality areas are marine biology ecology and physiology although I have a good understanding of chemical oceanography and physical Oceanography.
Experience I studied and am continuing my studies of M MarBiol at the university of Southampton
Organizations University of Southampton (uk)
National Oceanography Centre Southampton (uk)
JMBUK member
Expert: Rob Grafton Date: 11/14/2007 Subject: Octopus heartbeat
Question QUESTION: I am a volunteer docent at the Birch Aquarium at Scripps (Institution of Oceanography).
In discussing the issue of the multiple hearts in the octopus, the question has arisen as to whether the three hearts of the octopus beat in sequence, or in unison. I have not been able to find anyone who can/will answer this for me.
Thanks in advance
Rad Darling
ANSWER: I do not know is my honest answer, if you can give me a few days to try and look this up i might be able to come back with an answer. My guess us that they beat in sequence as to ensure that blood is pushed the correct direction but i am not sure.
I will get back to you.
Regards,
Rob
---------- FOLLOW-UP ----------
QUESTION: Thanks for the honest response.
I have contacted many "sources", but have had no luck getting an answer (sometimes not even a response).
A new question: The California Sheephead changes sex, color , and physical appearance at or about nine years of age (I have seen different ages in different sources). However, I have heard that the female will change colors during the mating ritual. Is this through pigmentation in the skin, or scales, or (?)?
Rad
Thanks. I look forward to your answer.
Answer I have found that the age at which maturation (gender change) occurs is thought to be dependant upon the food sources, (quality and abundance) and other environmental stresses (such as predation and competition), and regarding the colour change it will not be in the scales as fish's scales are the same as fingernails or ahir and do not have nereves in them so will not be able th change rapidly. It is more likely to be special pigment cells in the skin or, (i have not been able to find out how this specific species does it as i cant find any examples of the extent of change.) Some species (for example humans) go red by moving blood to the surface of the skin and paler by moving it away.
I hope this is some help, I'm sorry i couldnt find more on the colour changing aspect but it seems that there has been very little research done on this aspect of the species.
Regards,
Rob
I have a theory about the octopus heart. I have not been able to find any evidence about this so far but...
The circulatory system of cephalopods is an extensive system of vessels and capillaries . . . Blood within the vessels follows more or less the same route through the body as in other molluscs, but in addition to a systemic heart, the circuit includes two branchial hearts, which pump blood through the gills. There fore the "second" or "accessory" heart (split into two one for each gill) must beat at a different time to the main heart otherwise you would not get flow, just a general overall increase in pressure. Imagine the human heart in 4 sections 2 together in the main heart at the centre and two separate ones for the lungs (only 1 chamber each for the smaller ones.)
If you do manage to find something different please let me know.
