Scientists replicate the tide with two buckets, aquarium tubing, and a pump

From the American Journal of Botany

tide-sim-bucketInexpensive tidal simulator allows ecological studies of tidal marsh plants

Rachel MacTavish is growing salt marsh plants in microcosms that replicate the tide. She assembled them in an outdoor greenhouse at the Sapelo Island National Estuarine Research Reserve in Georgia, USA, with buckets from a hardware store, aquarium tubing, and pumps. Her tidal simulation units could be an important tool for preserving and restoring environmentally important wetlands, because they enable researchers to investigate tidal marsh plant growth in a controlled setting.

“Tidal wetlands are often influenced by many factors, and controlled experiments allow researchers to isolate and untangle the roles of individual variables,” explains MacTavish, a graduate student in the Department of Biology at Georgia Southern University. “I was inspired to construct and test this tidal simulation method as a way to examine the effects of added nutrients and salt in the water on salt marsh plant nutrient uptake.”

The design by MacTavish and coauthor Dr. Risa A. Cohen opens new doors for wetland research by overcoming limitations of previously developed tidal simulators. Each unit costs less than US$27.00, takes up less than two square feet of space, and does not rely on any external plumbing.

The simulators also support plant growth as well as real tidal flushing. MacTavish and Cohen compared the growth of the tidal cordgrass Spartina alterniflora in field sites and microcosm units. Their results indicated no significant difference in height, stem density, or above- and belowground biomass between the natural and simulated tidal treatments. The new tidal simulator protocol and the comparison of S. alterniflora growth in real tidal conditions versus the simulator are published in the November issue of Applications in Plant Sciences (available at

“Salt marshes have incredible value, protecting coastal populations from high wave energy during storms, sequestering large amounts of carbon, and serving as nursery habitat for many commercially important fishes,” explains MacTavish. “They are extremely productive ecosystems, providing nutrients and organic carbon to nearby coastal waters and beaches.”

Oil spills, heavy metals, and other sorts of water pollution continuously threaten tidal ecosystems. This new and simple mechanism to simulate the tide will enable researchers everywhere to uncover solutions to these and other hazards.

“I’m already using [the tidal simulator] in one of my experiments to study the concurrent effects of altered water column ammonium and salinity on S. alterniflora nitrogen uptake,” says MacTavish. “Another colleague at Georgia Southern University is also using it to examine the effects of sediment amendments on S. alterniflora growth under different soil organic matter concentrations to improve salt marsh restoration strategies.”


Rachel M. MacTavish and Risa A. Cohen. A simple, inexpensive, and field-relevant microcosm tidal simulator for use in marsh macrophyte studies. Applications in Plant Sciences 2(11): 1400058. doi:10.3732/apps.1400058.

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Bill Marsh
November 1, 2014 12:50 pm

Very interesting.

November 1, 2014 12:52 pm

Their results indicated no significant difference…..plants grew the same in a pot
Does the nimwit know there’s thousands of nurserys growing plants for restoration projects already?

Reply to  Latitude
November 1, 2014 12:58 pm

The experiment cost $27 not $27 million, at this rate she will be ostracised from the scientific community.

Brent Hargreaves
Reply to  old44
November 1, 2014 1:48 pm

Good point, old44. But $27 million is peanuts to big science. The UK Met office has recently spent either £97m on a computer. Or that might’ve been £970m – hey, it’s only taxpayers’ money and what’s in a zero?

stan stendera
Reply to  old44
November 2, 2014 12:13 am

MacTavish is a Scottish name. Leave it to a Scot to find a frugal way to do significant science. I’ll bet 50cents to fifty dollars she didn’t have a government grant. If she had such a grant the experiment would probably cost $27,000,000 .
PS> Frugal is NOT cheap.

Reply to  Latitude
November 1, 2014 1:27 pm

A stupid comment and an unwarranted ad hominem. The simulation of tidal ebb and flow, along with variations in salinity, turbidity, etc., doesn’t happen in “nurserys” (sic). Hence the pumps and tubing. Did you even read the post?
Their method has been validated to some degree: “The new tidal simulator protocol and the comparison of S. alterniflora growth in real tidal conditions versus the simulator are published in the November issue of Applications in Plant Sciences…”

Reply to  jorgekafkazar
November 1, 2014 3:39 pm

Dave Packard built a tide simulator which is on display at Monterey Bay Aquarium. As I recall it has no electronic parts, but a few electrical ones (motors, obviously). When questioned about this he said that
electronics weren’t reliable enough. He seemed to prefer the right tools for the job as opposed to flash and fury…..

Reply to  jorgekafkazar
November 1, 2014 4:33 pm

November 1, 2014 at 1:27 pm
A stupid comment and an unwarranted ad hominem.
Jorge, she didn’t compare plant growth to no tidal flushing at all….these same plants are commercially grown for restoration and research, in pots, with no tidal flushing………..and they grow perfectly fine
All they validated is that they are tough plants and will grow under different conditions….and that they did something aquarists have been doing for decades
I stand by my comment

Reply to  Latitude
November 1, 2014 7:38 pm

Read again. The design was validated by “compar[ing] the growth of the tidal cordgrass Spartina alterniflora in field sites and microcosm units.” In other words, between the same plants in a natural tidal environment and in the simulators. So your comment is definitely unwarranted ad hominem.

Reply to  Katherine
November 2, 2014 5:43 am

…and again, they did not compare plants growing not in a field site and not in a simulator
They validated nothing………..

Reply to  Katherine
November 2, 2014 11:56 am

Katherine, what does “ad hominem” mean?

Reply to  Katherine
November 2, 2014 1:17 pm

Katherine, can you point me to the place where the simulator simulates sediment accretion? This is very important, look at ‘tidal marshe’ and ‘accretion’. If accretion rates does not keep up with sea level rise then you get water inundation.
Sedimentation rates determined by 137Cs dating in a rapidly accreting salt marsh
Long-term Accretion Rates on Tidal Salt Marshes

Reply to  Katherine
November 2, 2014 1:22 pm

Katherine, the paper says

Third, the depth of tidal inundation can be altered by adjusting the height of the return aquarium tubing, which allows testing for the effects of drought or sea level rise.

How is this done without simulating accretion rates? I hope you can see the problem. Do you want me to be nice? OK I will be nice. Oh what a wonderful experiment, nice and cheap. Good luck to her. Now what if some eeejit comes along and uses the simulator to write a paper projecting inundation from sea water? Should I still be nice? It will be too late as it will be all over town. The horse would have bolted and I can’t catch her.

Reply to  Katherine
November 2, 2014 7:47 pm

Reply to Gerry “Ad hominem” is one of the worst fallacies in argumentation.
Ad hominem
When ever an argument attacks a person instead of presenting valid arguments for the the own view by a speaker or writer behind a thesis being argued against, that’s one of the worst fallacies of all in Theory of Science. In other words if the arguments used to take down an opponent is related to person or person’s opinion instead of being related to the content of the discussed subject, those arguments aren’t valid arguments and can never ever be used for a sound conclusion.
Commonly found in newspaper articles, in political debates and being used to defend a criticized hypothesis. (cf. the climate debate)
Fallacies in argumentation There are many more fallacies then presented in the link. These are some of the worst.

R. Shearer
November 1, 2014 12:59 pm

Any signs of cold fusion?

Reply to  R. Shearer
November 1, 2014 1:16 pm

No all Cold Fusion was offset by global warming from THE GRANT SCIENCE people.

November 1, 2014 1:12 pm

This proves nothing because Al Gore said so. And Barack “Sgt. Schultze” Obama says, “I see nooothiing!”

November 1, 2014 1:27 pm

Looks like an indoor pot growing setup.

Reply to  Harold
November 1, 2014 1:29 pm

Not to me.

Reply to  jorgekafkazar
November 1, 2014 3:55 pm

Why simulate something that you can see and study?
Just to keep your boots dry?
Also, she uses the stupidest possible expression, “organic carbon.”

Tom Harley
Reply to  jorgekafkazar
November 1, 2014 7:06 pm

So right, Alexander, they fare a lot worse than where I study tidal marsh plants:
Much wiser than electronics and buckets. Fortunately, I am surrounded by tidal marsh country.

Reply to  jorgekafkazar
November 1, 2014 7:42 pm

Because once you get the simulation correct, you can change variables to study the effect of the changes on the plants without polluting a tidal ecosystem.

Reply to  jorgekafkazar
November 1, 2014 9:48 pm

Why would the expression “organic carbon” be more “stupid” than “inorganic carbon” or “synthetic carbon”?
In fact, why is it stupid, at all?

Brian H
Reply to  jorgekafkazar
November 2, 2014 12:04 am

The definition of an organic compound is one based on carbon. So there are no such things as inorganic or synthetic carbon. Duh.

M Courtney
Reply to  jorgekafkazar
November 2, 2014 1:49 am

Katherine is exactly right.
This is real science. It is developing tools to test out how these environments behave.
This shows how bad AGW has become. Even good science is being thrown in with the darnel.

M Courtney
Reply to  jorgekafkazar
November 2, 2014 2:20 am

BrianH, inorganic carbon is carbon that is not bonded to Oxygen and Hydrogen.
Think about it, is Calcium Carbonate an organic compound?
Graphite, diamond and Buckminster Fullerene are forms of inorganic carbon as well.

Bruce Cobb
November 1, 2014 1:29 pm

Background in engineering perhaps?

Reply to  Bruce Cobb
November 1, 2014 1:37 pm

Definitely not in computer science. Too real world for that.

Reply to  jorgekafkazar
November 1, 2014 4:53 pm

The two fields are not mutually exclusive.
I am currently employed as a Software Engineer. I specialize in instrument control. I also have 30 years experience replicating extreme aquatic environments, including estuaries. Some of that was done professionally. During the 80s and 90s, my house would have put the fresh water section of most Public Aquariums to shame.
One of Blizzards game developers is also a published Marine Ecologist.
BTW, those responsible for designing the requirements for all of those infamous climate models are not software engineers.

November 1, 2014 1:42 pm

Wonderful, I wish her the best of luck but I have a question. Are my taxes paying for this? If so, why? I’m glad she found a less expensive way to do her research but I’m getting tired of working my @ss off at an economically viable job in order to pay for her to play with her science project instead of paying for her own hobby.

Reply to  nielszoo
November 1, 2014 2:02 pm

Why? Do you live in the state of Georgia?

Reply to  nielszoo
November 2, 2014 2:55 am

The point is that she has found a way for a other researchers to (a) save money, and (b) do potentially valuable new research. So taxpayers are among the winners. And it cost $0.0k!

Reply to  Mike Jonas
November 2, 2014 6:39 am

Sorry, not buying it. Taking money from me using the police power of government and threat of imprisonment to fund research is wrong. Taxpayers don’t win when the basic functions of government are unmet and instead billions are spent in “green” and “educational” public slush funds on projects like this. When the nation is secure, our borders, immigration and customs are uniform and lawful, the military is strong enough to protect us from anything, the “post roads” are well maintained and all that is done inside a budget that is balanced (with a minimum amount of taxation) then we can consider passing a Constitutional amendment that allows for funding research that might possibly benefit some miniscule fraction of the public. If we get back to that point in our society you will most likely find that private money will be available for this kind of thing like it was before the government takeover of education and science.

Reply to  Mike Jonas
November 2, 2014 3:37 pm

How do taxpayers save money if the simulator leads to a rash of misleading papers. Remember THIS PHRASE: ‘further research is required to examine the effects of sea level rise.’ The simulator is useless at projecting the effects of sea level rise because it does not simulate tidal marshland interactions completely. This is the SAME problem as Climate Models. Please people stop this now already!

Andrew N
November 1, 2014 1:43 pm

What! No computer model! How will they know what their baseline reality is?

Reply to  Andrew N
November 1, 2014 7:00 pm

Maybe a piece of paper, a pencil,and math, and if really needed a slide rule, maybe.

November 1, 2014 1:52 pm

Built one of these and ran a similar experiment for a project in 1976 while I was at school. Cost zero (but did use a school pump, I suppose).

November 1, 2014 2:07 pm

It sounds sorta scientific.
So there is that.

November 1, 2014 2:12 pm

Rachel MacTavish is growing salt marsh plants in microcosms that replicate the tide….
….tidal simulation method as a way to examine the effects of added nutrients and salt in the water on salt marsh plant nutrient uptake.”…
…The simulators also support plant growth as well as real tidal flushing…..

Was precipitation and groundwater included in the simulator? Is it significant or irrelevant? After reading the above and scanned the paper for the word ‘precipitation’ and ‘rain’ but could not find it.

Abstract – 2009
Effects of variable precipitation on the structure and diversity of a California salt marsh community
…..Although climatic variation has complex affects on annual plant communities, our experiments isolated important affects of total annual rainfall on the structure of annual plant communities that were similar to those that occurred with natural variation in rainfall. We conclude that variation in total annual precipitation promotes dynamic community composition and spatial distributions among years, and thus increases overall species diversity in the salt marsh.
Abstract – 1978
Nutrient and particulate fluxes in a salt marsh ecosystem: Tidal exchanges and inputs by precipitation and groundwater
…..Groundwater entering the marsh provides primarily N03-N and DON. Nutrient inputs through precipitation consist primarily of DON, NO,-N, and NIIcN……

November 1, 2014 2:16 pm

I find it rather sad this almost knee jerk negative reaction. Tidal flat systems are notoriously difficult to set up in a realistic experimental manner. If her system is reasonably close to realistic, as appears to be the case, she then has a wonderful system to apply variations and pose some “what if..?” questions. Tidal flats can be exceptionally productive ecological zones – only to most of us they look better when the tide is in. In many of our coastal systems, these zones have been drained or reclaimed for building. If many of our important commercial fish species start life in these zones, then reducing the fish nursery size must also reduce the number of fish available to be caught later.

Reply to  Warrick
November 1, 2014 3:29 pm

….If her system is reasonably close to realistic, as appears to be the case, she then has a wonderful system to apply variations and pose some “what if..?” questions…..

It only takes one missing factor to make any conclusions drawn from this simulator to be rendered false. What can you draw from a simulation that does not include vertical accretion rates, a fundamental pillar of survival for many salt marshes? What about precipitation? Were storms simulated by the aquarium style tubing?

Accretion of a New England (U.S.A.) Salt Marsh in Response to Inlet Migration, Storms, and Sea-level Rise
…..Horizon markers are useful in evaluating the role of short-term events, such as storms or inlet migration, influencing marsh sedimentation processes. However, sampling methods that integrate marsh sedimentation over decadal time scales are preferable when evaluating a systems response to sea-level rise.

Neil Jordan
November 1, 2014 2:18 pm

Page 5 of 6 of the paper includes the obligatory genuflection to sea level rise. Otherwise, this paper is a very good example of applied research, something I might want to try at home. The key items left out of the bill of materials in Appendix 1A were the programmable timers. I would anticipate that the $27 cost would increase. However, the authors were able to program their system to replicate semidiurnal tides, so they get a passing grade from me.

Reply to  Neil Jordan
November 1, 2014 2:55 pm

It’s good to see that they say……

Third, the depth of tidal inundation can be altered by adjusting the height of the return aquarium tubing, which allows testing for the effects of drought or sea level rise.

We can finally overcome the following problems of accretion rates etc. by using the ‘two buckets, aquarium tubing, and a pump’.

Abstract – 26 JUL 2006
The response of coastal marshes to sea-level rise: Survival or submergence?
In order to maintain an elevation in the intertidal zone at which marsh vegetation can survive, vertical accretion of the marsh surface must take place at a rate at least equal to the rate of relative sea-level rise. Net vertical accretion of coastal marshes is a result of interactions between tidal imports, vegetation and depositional processes. All of these factors are affected, directly or indirectly, by alterations in marsh hydrology which might occur as a result of sea-level rise. The overall response of coastal marshes to relative sea-level rise depends upon the relative importance of the inorganic and organic components of the marsh soil and the impact of increased hydroperiod on net accumulation. The varied combination of factors contributing to sediment supply, and their complexity at the scale of individual marshes, means that predicting the response of suspended sediment concentration in marsh floodwater to any changes which may occur as a result of sea-level rise, at anything other than the local scale is unlikely to be accurate. The impact of sea-level rise on net below-ground production is also complex. The sensitivity of certain species to waterlogging and soil chemical changes could result in a change in species composition or the migration of vegetation zones. Consequently, predicting the net impact of sea-level rise on organic matter accumulation is fraught with difficulties and requires improved understanding of interactions between vegetation, soil and hydrologic processes.

High Treason
November 1, 2014 2:24 pm

Can we put cAGW in the bucket too? Still, cAGW “research” costs even less- 1 penny to be precise. It starts as a thought (a penny for your thoughts) and an hypothesis(that humans…….) and the money gets thrown at you.)

November 1, 2014 2:30 pm

Hmmm . . . are there other environments that could be simulated somewhat in the lab with a little ingenuity?

Reply to  rogerknights
November 1, 2014 6:19 pm

I have created decent simulations of quite a few different desert aquatic habitats, acidic (black water) Amazonian streams, torrential SE Asian mountain streams, Borneo swamps, and a host of small brackish habitats, and a large “dirty” estuary. This last was very difficult and almost crashed three timers before I figured it out how to control the variations in nitrate loading. These simulations were pretty good. The whole point was to duplicate a piece of nature as accurately as possible. I would never assume that these simulations can reveal anything useful about the environments they were duplicating that direct observations could not reveal better. All one can simulate are the processes one ALREADY understands.

Reply to  DesertYote
November 1, 2014 8:07 pm

Sensible summary, great projects!

November 1, 2014 2:34 pm

Nobel Prize material (compared to IPCC achievements that is)

November 1, 2014 2:35 pm

Rachel MacTavish is growing salt marsh plants in microcosms that replicate the tide. She assembled them in an outdoor greenhouse…..

Does the bucket simulator in an indoor greenhouse simulate the same amount of sulfur outside? Sorry for asking such questions but the simulator stimulates my questioning mind.

Annual cycle of gaseous sulfur emissions from a New England Spartina alterniflora marsh
A flow-through chamber was used to measure the net gaseous sulfur fluxes (emission minus uptake) to the atmosphere from an area of Spartina alterniflora in a New England salt marsh. The fluxes of hydrogen sulfide, dimethyl sulfide, carbonyl sulfide, carbon disulfide and dimethyl disulfide were measured monthly over a year to obtain the annual emission estimates. Peak releases of the various sulfur gases did not occur simultaneously but were measured from July through to October depending on the individual sulfur species. The total annual emission was estimated to be 5.8 g S m−2 y−1, with dimethyl sulfide (49% of the total) and hydrogen sulfide (35% of the total) the major components emitted. The emissions of the other sulfur gases were nearly 10-fold lower.

November 1, 2014 2:43 pm

rogerknights said: Hmmm . . . are there other environments that could be simulated somewhat in the lab with a little ingenuity?
Probably, but an attempt to investigate the urban heat island effect with 4 paving slabs and a 100W light bulb is doomed from the start!

Steve Case
November 1, 2014 3:21 pm

I am reminded of the Free-air concentration enrichment for studying the effects of various CO2 concentrations in an open environment. First time I read about it, I realized the papers that it would generate were pre-written to claim excess CO2 was detrimental to plant life.

Reply to  Steve Case
November 1, 2014 7:03 pm

I am reminded of the Outer Limits episode Wolf 359.
Scared the bejeezuz outa me when I was a kid.
Based on a story by Richard H. Landau ironically titled “Greenhouse”.

Robert of Ottawa
November 1, 2014 4:24 pm

Frankly, why are they doing this? So they can learn how to stabilize tidal marshes? Tidal wetlands are, by their nature, transitory. They are not static.

Jon Reinertsen
November 1, 2014 5:03 pm

The one real world thing the experiment is not replicating is the effect of the tide rushing in and out. All the soil/mud is contained in the buckets, tidal marshes move constantly. Huge quantities of mud/soil are eroded and deposited on an almost daily basis. I lived in Derby, Western Australia for a number of years. The tidal range was up to 11 metres every day. When the tide was out the mudflats stretched for kilometres. By the way, those logs out there, aren’t logs. I also lived in Carnarvon, Western Australia. Fishing in the delta of the Gascoyne river was always a favourite, but you never quite knew where the channels would be following a flood.

Mark from the Midwest
November 1, 2014 5:07 pm

All the opinions about the efficacy of the specific research program aside, if you can figure out how to learn something, anything, for 27 bucks, you should be given instant control of the budgets of the EPA, the CDC, HHS, and I’ll even through in Homeland Security, since they’re clueless about how to spend money effectively

November 1, 2014 5:40 pm

Not WUWT finest moment. And not commenters most brilliant distinction. Folks, your eagerness to deconstruct everything does you no credit. As here. And harms your general credibility. Badly.

Reply to  Rud Istvan
November 1, 2014 10:04 pm

It’s not clear to me that this was posted in order to ridicule it.
Yes, there is the usual amount of vacuous commentary, but there are worthwhile observations, also.

Reply to  mebbe
November 2, 2014 1:04 pm

Rud, if flaws are not pointed out this simulator could be used by others to produce a scary marsh inundations sea level rise paper. Then we’ll point out the flaws again. Please consider accretion and sediment flow which does not appear to be factored in the simulator. Accretion is CRUCIAL for the ability of marshes to move with sea level rise.
Imagine a simulator of coral island atolls which failed to take into account accumulation of rubble. Any conclusions about sea level rise can be rightly dismissed. Now see this.

Arthur P. Webba et. al.
The dynamic response of reef islands to sea-level rise: Evidence from multi-decadal analysis of island change in the Central Pacific
Low-lying atoll islands are widely perceived to erode in response to measured and future sea-level rise. Using historical aerial photography and satellite images this study presents the first quantitative analysis of physical changes in 27 atoll islands in the central Pacific over a 19 to 61 yr period. This period of analysis corresponds with instrumental records that show a rate of sea-level rise of 2.0 mm yr- 1 in the Pacific. Results show that 86% of islands remained stable (43%) or increased in area (43%) over the timeframe of analysis……..
Abstract – 10 FEB 2014
Evidence for coral island formation during rising sea level in the central Pacific Ocean

November 1, 2014 6:45 pm

Someone ought to have sent the so called scientists in question on a Theory of Science course….. had been cheeper and had at least had a chance leading up to better knowledge….

November 1, 2014 6:59 pm

Very interesting.

November 1, 2014 7:03 pm

Reblogged this on Norah4you's Weblog and commented:
Why am I not surprised? As time goes by and the low quality of other so called scholars studies been presented, one by one, I have reached a conclusion. IPCC and their “scholars” are persons of Faith not persons of solid sound science….
It didn’t take long for the warmists to go from Thesis using Fallacies instead of Theories of Science to the present situation where IPCC acts same way as Christian Church leaders did in Medival Age and up to present. Of course(?) Humans must be the ones around which the sun and universe rotate 😛
IPCC preparing ‘most important’ document on climate change,bbs science environment 30 October 2014
10 important findings from the IPCC-reports, homepage Where have all the money gone?
9 significant scientific findings too recent to be included new IPCC-report, “World resorces institute”October 30 2014 Haven’t anyone of them studied more than Fallacies in subject Theories of Science? Who told them that Fallacies were/are legitim sound science????
Pseudo scientists are by no mean true to Theories of Science quote from The new faith of IPCC: Humans are Universe centre, Norah4you 204/10/31
as I wrote in comment below: Someone ought to have sent the so called scientists in question on a Theory of Science course….. had been cheeper and had at least had a chance leading up to better knowledge….

November 1, 2014 7:53 pm

As an addendum maybe she can reuse the set-up to figure out how what conditions might help kill off Phragmites australis?

November 1, 2014 8:35 pm

Kudos. Great idea. Should help to expand research and save the final tests for the real/expensive/time consuming natural environment. I walk around a salt water marsh twice a day and love the environment. Eel grass seems to be taking over though….don’t know if that’s good or bad.

November 1, 2014 8:46 pm

It’s disheartening to read the negative comments here.
We have a researcher who, rather than sitting at a computer conjuring scenarios that have the potential to result in multiple (probably useless) publications by simply altering variables, has gone to the ‘greenhouse’ and field to get some actual data.
In my experience, simple and inexpensive initial experimentation can result in the formulation of important questions that can then be explored in greater detail.

Reply to  Katio1505
November 2, 2014 1:08 pm

Katio1505 , when you present a paper for PEER REVIEW it will be looked at sceptically. It’s not about being nice, it’s about keeping bad science out. This simulator has failed to take into account all factors. The paper itself mentions that the simulator can be used to see the effects of sea level rise. IT CANNOT.

November 1, 2014 9:24 pm

Changing water levels each 6 hours does not replicate the tides … all it does is vary the depth of water, which is one element of the action. Most importantly, the incoming water brings nutrient and fresh water to the plants and the outgoing water flushes away the old nutrients and detritus.

Reply to  Streetcred
November 1, 2014 9:28 pm

Oh, by the way, worked on an artificial wetland construction a couple of years back for nitrate reduction at a sewerage plant that really did replicate tidal motion … incoming water, slack water, outgoing water.

November 1, 2014 9:40 pm

Evaporation adds some costs to that $27 , you can’t just top off the bucket with tap water. You need an R/O unit or a source of “fresh” saltwater.

November 2, 2014 4:17 am

With this experiment , how did they replicate “salt” (fresh water ) connected to ground state? When you look at a tree, do you only see what is above ground ? Have you ever stop to think how a trees root system looks like a frozen negative lightening strike, and above ground looks more like a positive lightening strike. The reason trees are so important to man is that they are one of the pathways the earth interacts with the atmosphere via point charge. Trees are a fistula that release heat ( electric potential) from growing.

November 2, 2014 4:19 am

Last word should be “ground”

November 2, 2014 5:01 am

Trees transport water against gravity on the day side like a wick . Here’s a thought if plants grow because of photosynthesis (light) then how does it start life in the dark? Here’s my thoughts , a seed ejects a packet of energy (green photons????) It’s shot into the atmosphere and we call them shoots. Once the shoot reaches the surface the photoelectric effect takes over.

Reply to  jmorpuss
November 2, 2014 8:03 pm

Photosynthesis will never feed the world, only fossil fuels can accomplish that.

Reply to  JoNovace
November 2, 2014 8:56 pm

Now, now.
I’ll politely disagree … a little bit.
Photosynthesis will ALWAYS feed the world.
But fossil fuel will reap that harvest, process it, store it, preserve it, and distribute it to the hungry many.

November 2, 2014 5:46 am
November 2, 2014 8:11 am

What a “vivid” discussion. The only thing I wonder if it was worth citing. Not because a 27 dollar experiment is less citation-worthy than a 27 million one, but I think the experiment is nothing that not any high school student with e.g. an Arduino interface and an interest in Aquaponics could not also have arranged but never thought of as, as some commenters noted, the plants don’t seem to depend much on tidal influences to grow well.

November 2, 2014 7:49 pm

I can replicate the greenhouse effect with a plastic bag and thermometer,[doesn’t] mean it’s worth anything though

November 2, 2014 7:56 pm

As a biologic experiement it sucks! As an experiement to study tide it’s pseudoscience. To be able to understand the natureforce gravitation one need to understand not only the most elementar parts of Theories regarding Energy. One also need to understand why string-theory’s 2nd string theory isn’t sufficient. In order to do that one need to understand everything from why energy is conserved up to theories of multi-room within the 2nd string theory AND why any experiment in order to study only graviditation needs to be able to be used not only in one dimension but in multidimension.
To explain half of the basic around that might help to understand Tide – but then we only looked at less than 1% of the premisses needed to be proven true of a part of the Graviditation theories still lacking a general explination of what Graviditation really is….

November 3, 2014 12:53 am

This can’t be real science .
What real scientist would not ‘ milk ‘ the public for a huge grant ?

Lloyd Martin Hendaye
November 3, 2014 6:51 am

Recall Feynman dipping Space Shuttle seals in a glass of ice-water at a Senate hearing following the “Challenger” disaster: NASA disbursed an exorbitant $10-mm+ on complex engineering studies, indeterminate and thereby perversely worthless. Like Galileo’s inclined planes, subtle concepts typically lend themselves to rudimentary mechanical evaluation.

george e. smith
November 3, 2014 11:01 am

With no external plumbing (they say), how do they provide for the input of new nutrients and removal of old effluents.
While tides may be just surface height bulges out in the deep oceans, they are decidedly in and out stream flows, in the presence of land.
How do you do that in a bucket with no external plumbing ??

November 8, 2014 10:56 am

The majority of comments make me embarrassed to be a WUWT reader. To the poster who thinks that any taxpayer-funded research is theft by force of his hard-earned income, that’s a philosophical argument that has nothing to do with this paper, and I guess you are prepared to throw away 90% of scientific discoveries of the past century including most cancer treatments, most modern antibiotics, nutrition, energy conservation, and everything else. As it happens, this paper was not funded by taxpayer dollars, you just have to read the acknowledgment footnote on the first page.
And no, it’s not a perfect tide simulator, and the authors discuss at least 7 other published tidal simulators. The problem is that if you want to study, for example, the effect of 5 different pollutants at 5 different doses, that’s rather hard to do if you only have one tidal simulator that uses 2-3000 liter water tanks, or that draws water from and discharges to a natural tidal basin. It’s a model system, and it will allow a lot of research to be done inexpensively and with good results. (A petri dish is not a realistic environment for most pathogenic bacteria, but you can’t deny that an awful lot of important science is done in petri dishes.)
And no, this has nothing to do with AGW or climate change or anything else, except that the authors mention they can easily simulate drought or sea level rise by changing the height of the water. Which is of course totally obvious, but one of the things you often say in the discussion sections of scientific papers.
It’s just a good bit of citizen science by a smart graduate student who wants to study tidal environments from a landlocked university.

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