Not every water problem has a supplier.
Some coastal stressors answer to work done in the water. Some are only held at bay by it. Some are climate, and no boat will ever touch them. Knowing which is which is the cheapest thing an authority can do this year.
There is a test that works surprisingly well, and it is geometric rather than chemical. Ask where the problem stops.
If the affected water has an edge — a basin, a lagoon, a harbour, an intake approach, a stratified layer below a thermocline — then the problem has a volume, and a volume can be treated, monitored and defended. If the same condition runs unbroken for three hundred kilometres of open coast, then whatever is driving it is bigger than any fleet, and treatment becomes theatre.
Everything below follows from that single question. We have sorted the stressors a coastal authority actually meets into three buckets, and we have been deliberately hard on our own bucket.
Bucket one
Stressors that answer to in-water work.
These share a shape: a defined volume of water, a driver that operates inside that volume, and a measurable state you can be held to.
Hypoxia in a bounded basin
NOAA defines coastal hypoxia as dissolved oxygen below 2 milligrams per litre — the level at which most aquatic life can no longer hold on. In a stratified estuary or an enclosed bay, the deficit sits in a layer with an edge, and oxygen delivered into that layer changes a measurable number.
2 mg/LThe dissolved-oxygen line that defines hypoxic waterNOAA NCCOS
Bloom biomass inside a defined water body
Bloom material in a lagoon, a marina, a bathing compartment or an intake approach is a finite mass of organic load sitting in a finite volume. That is a treatable object. Whether the bloom returns next month depends entirely on whether the nutrients that fed it are still arriving — which is bucket two.
The published validation for this class of treatment is pond-scale, and we say so below rather than in a footnote.
A local thermal hot spot
Warm water holds less oxygen and stratifies harder, so heat is usually upstream of the oxygen crash rather than separate from it. Where the hot spot is local — a shallow basin, a lagoon, a discharge-warmed margin — breaking the cap where it forms addresses the cause. Where the heat is basin-wide, it does not.
The distinction is not subtle and it should be settled during the site read, in writing.
Organic load at an intake or a nursery
Small volumes with high consequence: a drinking-water intake approach, a shellfish nursery, a stocked pen, a swimming compartment. These are the places where a few hours of treated water is the difference between a normal week and a closure, and where the economics are easiest for an authority to evidence.
They are also where a programme should start, because the result is visible inside one season.
Bucket two
Stressors that in-water work only buys time against.
Nutrient loading is the clearest case, and it is worth being blunt about the scale. The Mississippi and Atchafalaya basin delivers something like 2.76 billion pounds of nitrogen and 310 million pounds of phosphorus to the Gulf, and USGS modelling attributes more than seventy per cent of both to agricultural sources.
No vessel programme touches that. The nitrogen is applied to fields hundreds of kilometres inland, months before it reaches salt water, by people who do not answer to a coastal authority and who are making rational decisions inside their own economics.
Treating the receiving water while that fight goes on is not a substitute for winning it. It is a way of keeping the fishery, the beach and the intake in usable condition for the fifteen or twenty years the upstream work will take. Anyone offering it as an alternative to catchment reform is misleading you, and the misleading will be obvious by the second season.
The same logic covers sediment loading from land use change, legacy nutrient stored in bay sediments, and the slow return of a degraded seagrass bed. In-water work holds a line. It does not move it.
Source: USGS, nitrogen and phosphorus sources and yields in the Mississippi and Atchafalaya basin.
Bucket three
Stressors no vessel will ever touch.
Ocean acidification is the honest limit case. Surface water acidity has risen by roughly thirty per cent since the industrial revolution began, a fall of about 0.1 pH units, and NOAA's Pacific Marine Environmental Laboratory projects that on current emissions the ocean reaches a pH it has not seen in more than twenty million years. The driver is atmospheric carbon dioxide dissolving into the entire ocean.
pH support inside a bounded volume — a nursery, a reef flat, a hatchery intake — is a real and defensible intervention. Reversing a global chemical trend is not, and a coastal authority that buys a programme implying otherwise has bought a future press release against itself.
The same applies to regional marine heatwaves, to sea-level rise, and to shifts in ocean circulation. These are the conditions a coastal programme is designed around. They are not the conditions it removes.
Source: NOAA Pacific Marine Environmental Laboratory, ocean acidification.
What is actually published about this class of treatment
An authority is going to send whatever it is offered out for technical review, and it should. So here is what that review will find, put plainly, before anyone else characterises it.
The mechanism is established. Bubbles below roughly a micron stop behaving like bubbles: they carry a surface charge, stay suspended instead of rising, and transfer gas across an enormous combined surface area. That is characterised physics, and it is not ours.
The safety and efficacy validation that exists is pond-scale. In 2018 NOAA's National Centres for Coastal Ocean Science validated an ozone nanobubble aeration system on an eight-acre pond near Fort Myers Beach, reporting complete elimination of algae within forty-eight hours, with proper reoxygenation and no apparent harm to aquatic life. That study names another company's technology, not ours. It establishes the approach. It does not establish any particular vessel.
Ozonating seawater is not consequence-free. Bromide is abundant in salt water and ozone reacts with it readily; the hypobromite that results can go on to form bromate, which is a regulated concern. The controls are known and they are operating parameters — dose, contact time, pH, temperature — monitored in situ rather than assumed. Any supplier who tells your environmental team this is a non-issue has told you what kind of supplier they are.
And there is no published open-water record at municipal scale, from us or from anybody else in this category. The field record is a permitted trial. That is why a calibration phase on your own water, with viability parameters agreed in advance, is the only sensible way for a public body to enter one of these programmes.
Six questions worth putting in the tender
- Where does the effect stop? Ask for the physical boundary of the treated volume and how it was determined. A supplier who cannot draw it on a chart is describing a hope.
- Which bucket is our problem in? Ask them to say, in writing, which part of your stressor is upstream and outside their scope. The answer tells you more about them than any case study.
- What is the published evidence, and whose equipment does it name? Validation studies of comparable systems are legitimate support. Presenting them as validation of the supplier's own hull is not.
- What is measured, by whom, and against what baseline? Before and after profiles through depth, taken by someone whose invoice does not depend on the result.
- What are the by-products, and who monitors them? In seawater this means bromate at minimum. Ask for the monitoring obligation and the reporting line to your regulator.
- What happens when the calibration phase fails? Agree the exit before the start. A demonstration with no defined failure condition is not a demonstration.
Sources cited on this page
- NOAA National Centres for Coastal Ocean Science — Hypoxia research programme, for the 2 mg/L definition.
- NOAA NCCOS — Nanobubble technology validated for remediation of harmful freshwater algal blooms, 26 September 2018.
- USGS — Sources and yields of nitrogen and phosphorus throughout the Mississippi and Atchafalaya river basin.
- NOAA Pacific Marine Environmental Laboratory — What is ocean acidification?
- Alarivean, Inc. — the remediation and mitigation scope this argument sits inside.
Asked in the first meeting
Straight answers
How do we tell whether our problem is local or regional?
Look for the edge. If the low-oxygen layer, the bloom or the warm water stops at a physical feature — a sill, a headland, a basin mouth, a thermocline — the problem has a geometry and in-water work has something to act on.
If the same condition runs unbroken along hundreds of kilometres of open coast, the driver is regional and no vessel programme changes it. That is a site-read question, and it should be answered before anyone discusses capacity.
Does the treatment harm the marine life it is meant to protect?
The published evidence is encouraging and limited. NOAA NCCOS validated an ozone nanobubble aeration system on an eight-acre Florida pond in 2018 and reported complete elimination of algae within forty-eight hours, with proper reoxygenation and no apparent harm to aquatic life.
That study names another operator's equipment. It establishes that the approach can be run safely at that scale. It does not establish our vessel at yours, and we will not let it be read that way.
Can any of this reverse acidification along our coast?
No. Surface ocean acidity is up roughly thirty per cent since the industrial revolution began, and the cause is atmospheric carbon dioxide entering the whole ocean.
Supporting pH inside a bounded volume — a hatchery intake, a nursery, a reef flat — is a real intervention with a defensible boundary. Reversing the regional trend is not on offer from anyone.
If the answer is often "no", why is this site here?
Because the answer is not always no, and because the alternative to saying so honestly is a procurement that unravels in public two summers later.
A programme that starts with an accurate scope survives a change of administration. One that starts with a flattering scope does not.
Find out which bucket you are in
Ask for the unflattering answer first.
Send the water body, the stressor and the season. Alarivean will tell you where the boundary of the problem sits, and whether in-water capacity is the right instrument for it — including when the honest answer is that it is not.