Field observations that may make you uncomfortable.

S

scubaduderon

Member
I am a former marine reef keeper and haven't participated on this forum in a few years because I have moved to Guam.

There is absolutely no need to keep an aquarium here. I am surrounded by the Pacific Ocean on one side, and the Phillipine Sea on the other. There is incredibly lush sea life of all sorts and I go out quite a lot to enjoy it. Basically I try to get out at least once a week. On Sunday my wife and I were treated to a Titan Triggerfish and a squadron of squid, amongst hundreds of other fish species and corals.

Snorkeling and scuba have taught me quite a bit about the perfect environment for SPS corals, and it turns out it is quite different than what I remember from my reef keeping days.

I frequently see the most amazing SPS corals in areas where the natural Island fresh water is flowing out of the sea floor. I would call this the mixing zone. The fresh water is quite cool, I'd say in the low to mid 70's, with the bulk of the water in the low 80's, and with the surface water quite warm, usually in the low 80s, but sometimes it is actually uncomfortably warm, well into the low 90's. Of course the light level is quite high although there are many cloudy days. I mean many. The current is quite high on some days, way higher than I have ever seen in any aquarium, and that is where the corals grow strongest. There is an incredible amount of mixing, with the corals one second being hit with fresh water, the next with warm saltwater, etc. There are also calm days where the wave action and current is almost negligible.

I don't know what the measurements are for the freshwater bubbling up from the sea floor, but I know that it is very high in calcium and other minerals. The island is at least partially composed of coral. There is coral rock all over the ground, even at the high points. If you dig, you hit coral. Also, when you find volcanic rock, it often has embedded chunks of fossilized corals. In other words the island is dissolved by rain and pours out into the sea.

One puzzling phenomenon I have found is that the tap water coming up from municipal wells seems to be carbonated. It looks almost like milk until the gasses bubble out. I'm not sure if this is natural. I suppose it could be a remnant of the filtration process. Also forget about keeping your fixtures clean. In no time calcium forms...

I hope this helps you out. I guess what I'm saying is don't be afraid, I have seen all the rules broken here by mother nature, yet the corals have no problem at all. There are many areas of extremely lush growth that are continually beaten down by the feet of fishermen, snorkelers and swimmers, but they remain very healthy... The growth rate is super high. I guess millions of years of evolution have geared the coral here to grow in just such an environment. My guess is that if you look at what happens here and try to duplicate it, you will be very rewarded indeed.

Does this make any sense to any of you?

Ron
 
EdSnyder said:
Thanks for sharing, cool stuff:)
Click to expand...

Thanks.

I forgot to mention one thing. I have been snorkeling during rain storms. It rains really hard here. Picture a southern Florida downpour, except harder.

At any rate the rain causes localized changes in salinity, especially near the beach, yet the corals remain super strong. Rapid fluctuation in salinity is a completely normal for hard corals.

Ron
 
That is good research scubaduderon, thanks for sharing it with us. Us landlocked reefers need more of that kind of info. I get to the ocean as often as I can but a spot with a reef is over 24 hours away.
 
Back glass panel of aquarium--Coraline or no Coraline???

Back glass panel of aquarium--Coraline or no Coraline???

I'm starting to get corlaine algae growing on the back glass panel of my tank.

I'm just curious if most of you let it grow or if you like the clean look and scrape to remove it.

thanks
 
First off, I would like to thank you for your service with the Marines. :-)

Your observations are important, they show what many of have have discovered and tried to relate to others. Corals are very adaptive and can handle change, as long as it isn't rapid, at least until they have adapted to the rapid change. The old school days of trying to keep perfect parameters, temp, salinity etc are often the very reason we have failures. Our corals can become accustomed to no change in the tank environment and when there is a change it can be devastating. The use of an ATO and controllers that keep the heater and chiller sync'd so that the temp fluctuates only a couple of degrees a day can cause a ticking time bomb. A power outage is usually all it takes to bring these tanks down. The corals adapted to a couple degree fluctuation in temp and are stressed when it goes beyond that. Many of us let our temps fluctuate 6-8 degrees daily (some do more) and our corals do fine, they are adapted to that. I don't trust an ATO and add water when needed, my salinity also fluctuates but the corals are adapted to it. I strive to keep the chemistry as stable as I can, Ca Alk, Mag, N and P and let the rest fluctuate, it makes sense and as long as you go slow with changes until the corals are adapted.

Water flow is as important as light for SPS and the volume of water rushing past them in the wild we cannot replicate in our tanks. In my early days of being an SPS keeper, I read an article by Shimek or one of the gurus about the importance of flow...and as I increased flow in the tank, the SPS grew better and thicker. Flow is utilized by SPS for intake and outtake of nutrients and waste. The better the flow, the better the growth.

I am glad you started this thread, it shows what many of us have been saying for years.
 
First of all, I will say that I completely agree that corals are much tougher than most hobbyists like to give them credit for. Believing that they're delicate makes it a lot easier to convince ourselves (and significant others) that we HAVE to have the latest gadgets to keep them alive. It also helps us feel a little less incompetent when we're unable to keep an animal alive despite $3000 in equipment.

I also agree that more hobbyists need to go diving on reefs and actually pay attention to the conditions- the temperature and how quickly it changes, the clarity of the water, the water motion, maybe even take some nutrient readings, etc. Doing so would help clear up a lot of the myths in the hobby, including my personal pet peeve, that temperatures on reefs are stable.

However, in applying field observations to our tanks, we need to be careful and not simply assume that because something happens in nature, it's the best for our corals (and at the same time, not using the lame old excuse to justify everything "our tanks aren't the ocean). We need to not only ask whether a certain set of conditions occurs, but how widespread those conditions are, how frequently they occur, how long they last, whether they have any effect on diversity, and whether they cause physiological stress. It's important too to recognize that the visual signs of stress often don't manifest themselves for weeks to months after the initial insult, so you have to be sure you're using an appropriate observation period if you're basing your conclusion on simple observations.

In the case of salinity we actually do know that depressed salinity is the second leading cause of bleaching after high temperatures and that salinity variability has a strong influence on the distribution of reefs. While some corals don't seem to be bothered by it, it's probably not to our benefit to try to mimic it.

I'd be interested to see some pictures of the diversity and cover around some of these groundwater seeps to see if it's got any effect on what's living there. Also try to get some readings on that groundwater if you can. It would be interesting to see if it's fw or brackish and whether it's high in nutrients.
 
I have seen this as well in Hawaii where a lot of cold fw percolates up into the sw in places. It makes it hard to see (salinity blur)in the water and is very obvious. The difference with corals in our tanks, is that a temperature fluctuation is often coinciding with a power failure and thus flow is also stopped, causing a catastrophe. With good flow and clean water, they are pretty hardy to salinity and temp swings. Also, salinity swings in tanks due to water top off are temporary and small like in the ocean, but steady and prolonged swings due to incorrect params are pretty detrimental to some livestock.
 
Variation may be the key, at least within the shallow reef.

Variation may be the key, at least within the shallow reef.

sirreal63 said:
First off, I would like to thank you for your service with the Marines. :-)

Your observations are important, they show what many of have have discovered and tried to relate to others. Corals are very adaptive and can handle change, as long as it isn't rapid, at least until they have adapted to the rapid change. The old school days of trying to keep perfect parameters, temp, salinity etc are often the very reason we have failures. Our corals can become accustomed to no change in the tank environment and when there is a change it can be devastating. The use of an ATO and controllers that keep the heater and chiller sync'd so that the temp fluctuates only a couple of degrees a day can cause a ticking time bomb. A power outage is usually all it takes to bring these tanks down. The corals adapted to a couple degree fluctuation in temp and are stressed when it goes beyond that. Many of us let our temps fluctuate 6-8 degrees daily (some do more) and our corals do fine, they are adapted to that. I don't trust an ATO and add water when needed, my salinity also fluctuates but the corals are adapted to it. I strive to keep the chemistry as stable as I can, Ca Alk, Mag, N and P and let the rest fluctuate, it makes sense and as long as you go slow with changes until the corals are adapted.

Water flow is as important as light for SPS and the volume of water rushing past them in the wild we cannot replicate in our tanks. In my early days of being an SPS keeper, I read an article by Shimek or one of the gurus about the importance of flow...and as I increased flow in the tank, the SPS grew better and thicker. Flow is utilized by SPS for intake and outtake of nutrients and waste. The better the flow, the better the growth.

I am glad you started this thread, it shows what many of us have been saying for years.
Click to expand...

I will post some pics eventually. Right now I don't have an underwater camera. I do have some pics of the surface of the reef.

Basically what happens is this:

At distances which vary from literally the shore line to several hundred feet out there is a reef break. Waves of differing hights, due to the tide and weather conditions, either crash on the reef break or well over it. When the waves crash on the reef, they push water into the inner reef, and when the waves receed they draw water from the inner reef.

Rains pour onto the island and down into a "lens" of freshwater whose size and equilibrium are dependent on the size and frequency of the rains and the porosity of the land it exists in. This water dissolves mineral content from the island as it percolates into and out of the lens, and when heavy rains are present, delivers it to the reef. The temperature of this water as it percolates through the bedrock is approximately 10 t o15 degrees cooler than the surrounding water, and forms mixture areas that are heavily coraled.

Additional fresh water in the form of rain is directly delivered to the surface of the reefs. The amount varies by season and weather conditions. The amount of minerals in this water is negligable or at best extremely low. The rains also deliver surface water directly to the sea in the form of runoff.

Current flow within the reef system varies widely over time. Tides carry a varying amount of water into and out of the reef system. On calm days the flow is limited to tide action alone, and on rough days the flow is significantly increased due to wave action.

The reefs begin actually above the low tide mark and go down from there. The bulk of the reef's life that reef keepers are interested in begin a few inches below low tide down approximately 20 feet. Below this level the nature of the reef changes and is not discussed by me here.

Unfortunately I am not a scientist, so I do not have access to measurement equipment. My obeservations are anecdotal, yet present every time I am present on the reef.

For climate date see http://ns.gov.gu/climate.html

A very good coastal atlas can be found here: http://www.guammarinelab.com/coastal.atlas/index.htm

Tide charts can be found here: http://www.guammarinelab.com/tidecharts.html
 
Please post pics! And you living there makes it more of a reason to keep a tank in your home!!! You can stock it completely free!
 
I'v driven cross country in a mini cooper running air pumps to coolers and critter keepers and jugs full of ocean water just to bring home a few small fish, snails, starfish, sponges, and assorted algae... I can only dream of what I could do living out there...
 
scubaduderon, you should hook up a "local tank" and take a picture of that to show us. That would be awesome!
 
greenbean36191 said:
I also agree that more hobbyists need to go diving on reefs and actually pay attention to the conditions- the temperature and how quickly it changes, the clarity of the water, the water motion, maybe even take some nutrient readings, etc. Doing so would help clear up a lot of the myths in the hobby, including my personal pet peeve, that temperatures on reefs are stable.
Click to expand...

yes what about tide in tide out water changes...large water changes exposing corals while it takes place?
 
I put up a few pics of the surface waters.

I put up a few pics of the surface waters.

twelvejewelz said:
Please post pics! And you living there makes it more of a reason to keep a tank in your home!!! You can stock it completely free!
Click to expand...

Actually being here makes me feel a bit uncomfortable about reef keeping myself. When you see these guys in the wild, tooling around looking for food, circling about in mating dances, waiting for their turn at a cleaning station, running away from that big strange fish (me), you realize how happy they are and how great they fit into their environment, and how big that environment is. I loved my fish and managed to pass on quite a few, but I also killed a few too.

Ultimately I hope conversations like these improve the hobby, and help to create more vibrant living systems. That would help the hobbyist and the fish and reef too

Picture this: I am hovering about 5 feet above the reef. I bring out a plastic bag filled with corn, peas, bits of meat. Slowly I begin to release the food. Swarms of hundreds of fish of almost every variety circle about, feeding in a frenzy that is hard to imagine. This is a weekly reality here. Imagine a 9 inch Naso Tang, no imagine 100... Picasso Triggers everywhere, Yellow tangs, Purple Tangs, Gobies, Sea Cucumbers, corals of 2 hundred varieties....

http://www.naturefootage.com/video_clips/CW01_056

http://vimeo.com/2006962

O.k. Something I see on every trip. There is a Gobi sitting at the mouth of it's cave. If you wait around very still, soon a small shrimp will emerge from the cave with a huge load of sand in its claws. It dumps the sand at the base of the cave and disappears back into the cave to make another trip. Every Gobi has a partner, it is the way they live. They cooperate. I am very lucky indeed.
 
Okay that is very interesting and amazing. i've been in a lot of places over here for snorkeling and dives. some places that i've been have spots where it was how you described it, fresh meeting salt. whether it was a river or just fresh water creeping under formations of rocks, all that i've seen was like a barren wasteland with maybe some macroalgal growth together with blurriness because of the mixing waters. Maybe it really depends on a lot more factors such as location, tides, current, etc. It is really nice to be a reefer at the equator, hehe, frags galore!
 
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