80 degrees too warm?

Years ago I ran across some forum that spoke about how raising your temp to 80 in a reef can stimulate coral growth and hungry fishes. Of this reason I have always ran my tank at this temp. Mind you, I have never seen my tank explode with growth and my fish are always hungry but I feel they would be regardless, just like everyone else's.

76-79 degrees seems to be everyone's target. So, if any, are there any adverse affects to my tanks temp?

 

Corals generally do best within a few degrees of the long term average of the reef they come from, but can usually acclimate to other temps (within a reasonable range, which will vary from coral to coral). Most natural reefs are in the low to mid 80s and I've run 82-84 and had a nice thriving system. I haven't really noticed a difference running other temps though. Right now I'm more in the 77-78ish range, but more to keep electric bills down. When I was running higher, it was for the same reason; I was on the second floor and it was hot... People make a big deal about temp, there is little if any evidence that it actually matters much as long as it is somewhere around 76-84 (give or take, this is conservative).

In theory higher temps will increase metabolism and higher metabolism will result in higher growth rates. On the other hand increased temp with increase bacterial counts. So, depending on what is growing, that could be bad. I've been all over the board and haven't found any difference in survival or growth in my systems at any temp within the stated range though. I think if it is easier to run higher,or lower, so be it. Or if it's cold out, you could run higher for more of a buffer in a power outage and so on. The only key point that really seems well established is that corals seem to tolerate short term swings, but longer swings more than a few degrees from the acclimation point can be fatal.

 

I feel the same as you. Thanks for the detailed response. At this point, it's not broke so I won't fix it!

 

Stability is more important than an exact number. If your tank (fish and corals alike) are acclimated to 78 then that's where they will do best. Same goes for 84. If you acclimate them to 84 then they will do fine. Its when you have, for example, 74 at night and 84 during the day with the big temp swings that you start having serious problems in the tank.

 

Agreed. Stability is the key when it comes to temp. Now I have noticed my tank is much happier now that I run a chiller and my tank stays at 76-78. It used to run 80-83 before the chiller. If your tank is thriving then keep it where it is and focus on stability with your current temp.

 

Maybe, depends how you loook at it and which corals your referring to. There are a lot of short term swings in the ocean and researches really only consider long term changes in temperature when evaluating heat streas of reefs. Short term swings within the acclimated tollerance range are not usually considered stressful, primarily long term changes are considered . Short term swings may be an important part of the acclimation process for some corals though.

The article is Oliver and Palumbi (2011) "Do fluctuating temperature environments elevate coral thermal tolerance?"

From is "Our work suggests an additional element may be a factor in the hardening of corals to high temperatures: high-frequency, low-duration (HFLD) heating."

And this may be due to changes in gene expression patterns in order to shift expression patters to optimize heat tolerance before longer term change occurs. This is described in Barshis et al. 2012 "Genomic basis for coral resilience to climate change."


Abstract
Do fluctuating temperature environments elevate coral thermal
tolerance?
T. A. Oliver • S. R. Palumbi
Received: 11 March 2010 / Accepted: 3 January 2011
Springer-Verlag 2011
Abstract In reef corals, much research has focused on the
capacity of corals to acclimatize and/or adapt to different
thermal environments, but the majority of work has focused
on distinctions in mean temperature. Across small spatial
scales, distinctions in daily temperature variation are common,
but the role of such environmental variation in setting
coral thermal tolerances has received little attention. Here,
we take advantage of back-reef pools in American Samoa
that differ in thermal variation to investigate the effects of
thermally fluctuating environments on coral thermal tolerance.
We experimentally heat-stressed Acropora hyacinthus
from a thermally moderate lagoon pool (temp range
26.5–33.3C) and from a more thermally variable pool that
naturally experiences 2–3 h high temperature events during
summer low tides (temp range 25.0–35C). We compared
mortality and photosystem II photochemical efficiency of
colony fragments exposed to ambient temperatures (median:
28.0C) or elevated temperatures (median: 31.5C). In the
heated treatment, moderate pool corals showed nearly 50%
mortality whether they hosted heat-sensitive (49.2 ± 6.5%
SE; C2) or heat-resistant (47.0 ± 11.2% SE; D) symbionts.
However, variable pool corals, all of which hosted heatresistant
symbionts, survived well, showing low mortalities
(16.6 ± 8.8% SE) statistically indistinguishable from controls
held at ambient temperatures (5.1–8.3 ± 3.3–8.3%
SE). Similarly, moderate pool corals hosting heat-sensitive
algae showed rapid rates of decline in algal photosystem II
photochemical efficiency in the elevated temperature treatment
(slope = -0.04 day-1 ± 0.007 SE); moderate pool
corals hosting heat-resistant algae showed intermediate
levels of decline (slope = -0.039 day-1 ± 0.007 SE); and
variable pool corals hosting heat-resistant algae showed the
least decline (slope = -0.028 day-1 ± 0.004 SE). High
gene flow among pools suggests that these differences
probably reflect coral acclimatization not local genetic
adaptation. Our results suggest that previous exposure to
an environmentally variable microhabitat adds substantially
to coral–algal thermal tolerance, beyond that provided by
heat-resistant symbionts alone.


Abstract
Daniel J Barshis et al 2012
Genomic basis for coral resilience to climate change

Recent advances in DNA-sequencing technologies now allow for in-depth characterization of the genomic stress responses of many organisms beyond model taxa. They are especially appropriate for organisms such as reef-building corals, for which dramatic declines in abundance are expected to worsen as anthropogenic climate change intensifies. Different corals differ substantially in physiological resilience to environmental stress, but the molecular mechanisms behind enhanced coral resilience remain unclear. Here, we compare transcriptome-wide gene expression (via RNA-Seq using Illumina sequencing) among conspecific thermally sensitive and thermally resilient corals to identify the molecular pathways contributing to coral resilience. Under simulated bleaching stress, sensitive and resilient corals change expression of hundreds of genes, but the resilient corals had higher expression under control conditions across 60 of these genes. These “frontloaded” transcripts were less up-regulated in resilient corals during heat stress and included thermal tolerance genes such as heat shock proteins and antioxidant enzymes, as well as a broad array of genes involved in apoptosis regulation, tumor suppression, innate immune response, and cell adhesion. We propose that constitutive frontloading enables an individual to maintain physiological resilience during frequently encountered environmental stress, an idea that has strong parallels in model systems such as yeast. Our study provides broad insight into the fundamental cellular processes responsible for enhanced stress tolerances that may enable some organisms to better persist into the future in an era of global climate change.

 

That's a bit much man. All that was said is stability is important as much as a number. And if the tank is thriving at 80 then keeping that number stable is important.

 

It's possible to not read what is written, but not possible to read what isn't written. LOL.

And that's where the "myth" begins. If your read through these forums, everyone preaches "stability". However, this ignores the literally thousands of reports on the forums, over the years, of people who have large daily swings and thriving tanks. It also people report keeping their tanks very, very stable and loose everything when there is a minor temp swing. There is now an plausible scientific explanation for these observations, which is pretty cool. You don't need to understand the specifics, but is not a bad idea to understand that there is more to life than stability...

 

BTW, what was cited above suggests that minor temperature variation, may help corals prepare for more and survive significant variation. So, unless you have backups generators heaters etc.. And never expect any swings, then it may actually be better to allow some minor variation. I.e. 100% stability is not necessarily the best approach, regardless of what is written on the Interweb.

 

Be forewarned that m2434 is going back up his comments with scientific data/research.
Point is any member would get the same thorough response. I appreciate that he takes the time to post the information.