Big water problems require persistent care.
The stressors we get asked about most, and the multiple ledgers that end up paying for them. Which ones you actually carry decides service commitments, fleet dynamics and subscription pricing.
Big water problems
One estuary receives all of these at once.
They arrive together and they compound. A bloom rides in on a nutrient load, the oxygen deficit follows the bloom down through the column, and a harbor master gets all three in the same August along with the phone calls.
Stressors include
01 — Dead zones
Oxygen missing from the layer that lost it. The duty the fleet was built around.
02 — Harmful algae
A deadline rather than a condition. The outcome is worthless unless the hulls are already there in the right week.
03 — Nutrient loading
A cause that arrives from land on a decades-long clock, and a firewall you can put at the inflow now.
04 — Heat stress
It sits upstream of the deficit and the bloom. Spot cooling answers part of it, over a defined place and never a whole sea.
05 — Harmful emissions
Methane and nitrous oxide a treated water body stops making, set against the energy a program burns.
06 — Microbial consortia
Ballast tanks, quarantined basins, treatment trains. A dose that meets a boundary.
07 — Hydrocarbon leachates
Fuel residues, tars, and the additives coming off degrading plastic. The leachate is the target, not the solid.
08 — Heavy metals
Left dissolved, and kept off your dredging schedule. The boundary here matters more than any claim.
Who carries it
09 — Public health
One guideline value is not a threshold, and the notice is signed by somebody who does not work here.
10 — Marine life
Not a beneficiary category. The instrument that tells you whether the water changed.
11 — Blue economy
Two and a half decades of growth measured in output, with no series for the condition of the input.
A strategy desk that works in the planetary boundaries framework will recognize several of these headings as control variables it already reports against, and the crosswalk between the two vocabularies is set out on Aquatic Prosperity rather than here. The one piece of that chemistry this page carries is under 05, harmful emissions, where NOAA's acidification figures are quoted as background and not as anything a program treats.
01 — Dead zones
Oxygen is the deficit that arrives on a calendar.
Hypoxia is seasonal, it is driven by heat and stratification, and it forms in the part of the water column that surface aeration never reaches.
NOAA sets the hypoxic line at 2 mg/L of dissolved oxygen. That number is a definition, not a target: a review of sensitive species in the Delaware estuary put the lethal-level requirement between 4 and 6.4 mg/L. Water at 2.5 mg/L is not hypoxic by the definition and is still killing things.
The scale gets measured every summer, and 2025 was a comparatively good year in the Gulf of Mexico: 4,402 square miles, the fifteenth smallest in thirty-nine years of records. That is what a good year looks like. Worldwide, Diaz and Rosenberg counted more than 400 coastal dead zones in 2008.
This is the duty the vessels were built around. Water is drawn from the layer that has run out, taken through the reactor aboard and returned to that same depth carrying oxygen again — held continuously, with the readings reaching somebody outside this company at the same moment they reach our crew.
02 — Harmful algae
A bloom is a deadline with a color.
Every other stressor on this page can be worked on in your own time. This one cannot. Cells double, wind pushes the patch, and the difference between a treated week and an untreated one is decided before most procurement departments have opened a file.
So what an operator is actually selling against algae is not a machine. It is presence — hulls already inside a service zone, gases already contracted, crews already accredited to that regulator, so that the response to a forecast is a course change rather than a scramble. Presence of that kind cannot be bought at short notice, which is why it is sold as a running subscription rather than as a callout, and why the price of holding it beats the price of the alternative by a distance anyone who has chartered in an emergency can estimate for themselves. Blooms in the water next door get intercepted under the same arrangement, because a patch four miles away is your patch in two days.
The cells are the visible half. The toxin is the half that closes a beach after the water has gone clear again, which is why the measurement obligation runs on the toxin assay rather than on cell counts. Bloom water is drawn into a contained reactor and worked there, so cells come apart inside a vessel rather than in the bay. Contained is a word about the reaction, not about impounding anybody's water — the flow never stops, there is nowhere aboard to stop it, and the treated water goes back into the same patch it was drawn from. Toxin work is the tier above that. The envelope tightens there rather than the flow halting: settings held further back from the line, oversight closer in, and instruments that shut the oxidant or the intake before a discharge can leave outside its figure.
Work under this company's now-completed research agreement with NOAA established that the treatment neutralizes toxins rather than precipitating anything out — our own account of our own research, and a research agreement was never an endorsement. The treatment page carries it in full; HABslayer runs the duty.
03 — Nutrient loading
Fixing runoff sources may take twenty years, and should still be started.
Two clocks run here, and only one of them usually gets discussed. Cutting what leaves the land is the long answer. Intercepting the loading dynamic where it enters the water is the one available now.
The Baltic is the case that settles the argument in both directions. Nine countries agreed reductions, delivered a large part of them, and had them audited: against the 1997–2003 reference period, normalized nitrogen input was down 11 percent by 2022 and phosphorus down 32 percent. Real work, measured properly. The Baltic Proper and the Gulf of Finland still failed their maximum allowable input for both nutrients, and the hypoxic area of that sea has gone from under 10,000 square kilometers before 1950 to more than 60,000 since 2000.
Read that as an argument against catchment work and you have read it backward. It is an argument about lag. Nutrient already in a system keeps cycling long after the tap is turned down, so the years between the policy and the recovery are years somebody has to get through with the water they have.
Which is where the second clock starts. The oxidation and aeration firewall that protects a coastline from what arrives on the tide can just as well be set at a runoff hotspot, on the inflow itself, to mitigate the loading dynamic before it spreads outward. Dr Peter Moeller of NOAA observed an effect on nitrogen and phosphorus in this work. We are still studying it, we are not going to put a number on it here, and the effect does not switch off when the catchment program finally lands.
None of this is an argument against fertilizer. Fertilizer feeds people, and a plan that starves growers to save a bay has simply moved the harm somewhere less photogenic. Keep optimizing agriculture — fewer harmful pesticides, the right quantity of nutrient in the right place — and handle the runoff where it enters the water, which is cheaper and faster than throttling how food gets grown. HAB Control sets out how both clocks are written into one strategy.
04 — Heat stress
Heat gets there first, and much of this page follows it in.
Warm water carries less oxygen and resists mixing, so a thermal event is usually what set up the deficit and the bloom that arrive after it.
It is asked about often enough that leaving it off this list stopped making sense. The sequence rarely varies. The column caps, the layer beneath it stops being resupplied and starts spending what it had, and a bloom finds the warm, still skin it wanted all along. By the time a bleaching alert or a fish kill reaches a newsroom, the heat that arranged it has already peaked.
Part of what a program carries against this is localized spot cooling, delivered by nanobubble clouds. Thermal relief over a defined place — a reef, a shellfish nursery, the approach to an intake — held through the window where the exposure actually sits. What a client holds us to is the state of the water and the safety parameters around it. Instruments read both live, and so does an institution that does not answer to us.
Then the boundary, which is the part worth being blunt about. Spot cooling does not cool a sea, a basin or a region, and the same exclusion is written into how a program is put together. Where the heat arriving at a site is a basin-wide signal with no local component underneath it, working one lagoon changes nothing that matters, and this is a program we decline to sell. That answer comes out of the site read, well before anybody drafts a contract.
So no degrees, no area, no duration. We have published no cooling figure because none has been measured on your water yet, and the first honest one comes out of the calibration phase on the site itself. ReefHealer carries the reef case and the limits that travel with it.
05 — Harmful emissions
Both sides of this ledger get counted, and one of them is larger.
A hull burns fuel getting to a zone and runs industrial gas once it is there. That is a footprint, it is real, and it is quantified during the site read, which is where a counterparty paying attention asks for it.
The other side of the ledger is emission that never happens. An anoxic water body is a methane source — think of what a basin like Lake Erie gives off in a bad August — and a nutrient-loaded coast is a nitrous oxide source, the kind of chemistry that sits off a shoreline like Lima's. Restore the oxygen and that production is avoided rather than offset. In those settings the systems consume so much less than they avoid that the net case is not a close call, and the avoided emission is the kind that would qualify as premium nature-based avoidance measured in CO2 equivalent.
So the honest position is that Alarivean is eligible for climate finance where the case supports it, and would structure a program that way. What we will not do is measure our own avoidance and then sell it. A credit has to be quantified by somebody with no stake in the treatment, against a protocol agreed before the work starts. That separation is the entire argument behind Credible Exchange. No tonnage is claimed on this page and no credit has been issued.
The adjacent chemistry is on the public record and is not a claim about our equipment. NOAA reports ocean acidity up roughly 30 percent since the start of the Industrial Revolution, about 0.1 of a pH unit. Aragonite saturation has fallen by about a fifth across much of the surface ocean. Above a saturation state of 3, shell-forming life is more likely to survive and reproduce; below 1, aragonite shells begin to dissolve.
06 — Microbial consortia
Organisms inside a volume somebody can draw a line around.
Organisms held in a bounded volume — a ballast tank, a quarantined basin, a treatment train — respond to a controlled oxidant duty, and the response has been measured by people who are not us. NCCOS-affiliated testing in 2020 evaluated a commercial nanobubble ozone system on ballast water and found it effective against algae, bacteria and motile zooplankton, with no statistically significant adverse residual toxicity in the receiving water.
That testing was run on another company's equipment, and the evidence page gives the document and what it establishes. A contained reactor treats what passes through it, and a coastline does not pass through anything, which is why this duty is priced against tanks and enclosed basins rather than against a bay.
The regulatory frame is the IMO's ballast water convention, in force since 8 September 2017, with a discharge standard of fewer than ten viable organisms per cubic meter at 50 micrometers and above. One boundary travels with that number: the largest organism class, resting cysts and large zooplankton, is the most oxidant-resistant of them and is not claimed on a single immediate-discharge pass. ChemSlayer is where that duty lives in this network.
07 — Hydrocarbon leachates
Petroleum-derived material leaches for as long as it sits there.
The category is wider than the debris everyone photographs, and it is chemistry rather than objects. Fuel and oil residues worked into a sediment. Tars. Weathered bunker traces along a bulkhead from a release nobody logged. And the additive load coming off plastic that is breaking down in place, which is one case inside the category rather than the whole of it.
Take the plastic case, because it is the one people can see. A crate on a seabed. Film wrapped around a mooring chain, pellets that went over a side in 2019, sheeting piled at the top of a beach by one winter and buried by the next. None of it is going anywhere quickly. What does move is the chemistry — the additives that were put into the polymer to keep it flexible, stable and colored come out of it into the water around it, season after season, while the object itself sits there looking inert.
That leachate is what a treatment stage reaches, and the part it reaches best is the organic part — the plasticizers, the bisphenols, the phenolic stabilizers, and the dissolved fraction of an old hydrocarbon load beside them. Those are the compounds advanced oxidation is built to take apart. Affected water is drawn into the reactor at flow, treated on the way through, and handed back verified into the water it came out of. Nothing waits aboard. The oxidant does its work inside the hull, not loose in the bay, and a single pass is not a claim of complete mineralization.
Two boundaries belong in the same breath, because both decide whether we are the right call. The metal in a metal-based stabilizer or pigment is not going anywhere — oxidation disables a molecule, and a metal is still a metal afterward. Where that additive is an organometallic, and plenty of them are, the organic half of it is reachable and the metal half is not, so the compound changes and the inventory does not. And the plastic itself is untouched: nothing in a treatment pass degrades, dissolves or removes a polymer.
Recovery of the material is a separate duty and a separate line in a scope. Floating and shoreline plastic inside a contracted zone comes out under the Beach Cleanse augment — a workboat, a crew and a written scope agreed before anyone quotes it. Where the hydrocarbon is arriving now rather than weathering in place, the spill and contaminated-discharge duty sits with ChemSlayer.
The basis is Alarivean's own account of work carried out under a private research agreement with NOAA whose term has since ended, rather than a published result. No agency endorsed it then and none endorses it now.
08 — Heavy metals
What happens to a metal decides who inherits it.
Two answers are on offer in this market, and they land on very different budgets.
Precipitation is a relocation. A metal that drops out of solution and settles into sediment has not stopped being a metal; it has become a dredging problem, a benthic problem and, in a shallow basin, a problem that comes back the next time a storm or a propeller stirs the bed. A coagulate-and-settle answer leaves you holding exactly that, whether or not the proposal in front of you puts it in those words.
So the useful thing here is the mechanism, and it is the one stated for every other contaminant on this page. Nothing is removed from your water. What gets neutralized is the chemistry that made a thing harmful, and a hydroxyl radical does not destroy a metal, so for a metal that means the organic groups bound to it — reviewed work on heavy metal complexes describes the ligand coming apart and the ion being released, on industrial wastewater rather than on a bay. The species changes, the quantity does not, and nothing settles onto your bed on the way through.
What a contained pass promises is the other half. Oxidation takes a molecule apart; it does not push a metal out of solution and onto the bed, so this stage hands nobody a sediment inheritance. Where a metal load is the problem a basin actually has, the site read says so in week one.
09 — Public health
A health authority should be holding the same readings we are.
In August 2014 a bloom on Lake Erie reached Toledo's intake, and roughly half a million residents were advised not to drink the tap water. NOAA Fisheries puts the shoreline property-value loss from that single event at $10.05 million. The notice that closed the supply was signed by a public official, not by a contractor.
Guideline values are where the real damage gets done, because there is rarely just one. WHO publishes three for total microcystins — 1 microgram per liter for lifetime drinking-water exposure, 12 for short-term, 24 for recreational water. Quote only the first and a directorate ends up issuing a do-not-drink notice in circumstances WHO's own guidance does not call for. Quote only the last and the opposite happens.
The rest is exposure that does not read on an intake meter at all. Aerosolized brevetoxin from red tide produces an upper-respiratory syndrome, and asthmatic subjects in one study reported symptoms up to at least five days after a single hour of exposure. Domoic acid has no antidote and is not destroyed by cooking or freezing.
Independent oversight
The health authority that signs the notice should not be waiting on our report to write it. Local scientific institutions hold the live feeds from the situation report onward, so a second copy of the record exists outside this company from the first reading. How that arrangement works.
10 — Marine life
The measurement that decides whether the water actually changed.
Biology is the only reading that cannot be produced by our own equipment, which is exactly why it is the one worth contracting somebody else to take.
What a kill event looks like in a record: Kuwait Bay, August and September 2001, more than 2,500 tonnes of wild mullet, roughly a hundred times the size of a red-tide-linked kill two years earlier. The peer-reviewed account attributes it to bacterial disease, harmful algae and eutrophication acting together — three of the headings on this page, in one bay, in one month.
Reefs carry their own scale: between January 2023 and March 2025, bleaching-level heat stress reached 84 percent of the world's reef area across 82 countries. And the stock in the water is now mostly farmed, aquaculture having passed capture fisheries in 2022 at 94.4 million tonnes against 92.3 million. Half the world's aquatic protein is grown in water somebody has to keep alive by design. ReefHealer covers the reef duty and its limits.
11 — Blue economy
Measured in output for thirty years, and never once in the condition of the input.
The OECD puts the ocean economy at US$2.6 trillion of gross value added in 2020, double its 1995 figure in real terms — fifth place, if you entered it in the table of national economies. Marine and coastal tourism is projected to be its biggest sector by 2030, at US$777 billion and more than 8.5 million jobs.
Read the series and you will not find a line for whether the water was in good condition while all that value was produced. It has never been an entry, which is why the cost of a bad season shows up scattered across cancellations, membrane replacement, throttled output and closed harvests, and never under a heading anyone budgets against in advance.
Which is also why buying this work reactively is the expensive way to buy it. A cost with no heading still gets paid, in pieces, by whichever sector failed first, and everything bought during an event is bought without leverage. A subscription running before the event puts that money under a heading, at a rate that exists only because the work is preventive. Nobody is charged for foresight here. They are charged less for having it.
Marine Prosperity makes the institutional version of this argument; AquaProsper makes the operator's.
Where the stressor becomes a place
Three water types, and the difference between them is time.
The same deficit behaves differently depending on how long the water stays put. That single variable changes the treatment, the owner, the regulator and the price, which is why the argument splits three ways from here.
Asked in the first meeting
Three that arrive by return
We have three of these problems at once. Is that three programs?
One. A single zone carries the vessel tier, the gas supply and the augments on one subscription, and the duties run from the same hulls in the same weeks.
The scope names which stressors sit inside it and which sit outside, in writing, before anything is signed. Adding a duty once the program is running is a variation with a price, not a favor.
We have plastic accumulating in our bay. What would a program do about it?
Work the chemistry, not the object. Plastic additives sit inside a wider category — the organics that petroleum-derived material leaches into water, fuel and oil residues and weathered bunker traces among them — and the plasticizers, bisphenols and phenolic stabilizers coming off degrading plastic are the worked example. Those are what the oxidation stage takes apart, inside a contained reactor aboard the vessel. The metal in a metal-based additive stays a metal, though where the additive is an organometallic the organic half of it is reachable. The polymer itself is unaffected.
Floating and shoreline material is recovered under the Beach Cleanse augment, which is a workboat and a crew rather than a chemical duty. Both go in the scope as separate lines with separate costs.
Do metals come out of the water, or end up in our sediment?
Neither, and that is the point rather than a hedge. Nothing is removed from your water and nothing is dropped into your sediment; what happens is that the chemistry making a contaminant harmful gets neutralized in the reactor. For a metal that is the organic chemistry bound to it, so the form changes and the quantity your water holds does not.
A metal does not drop out of solution because it went through a reactor either, so the pass leaves your bed as it found it. If the metal load is the problem you actually have, the site read will say we are the wrong instrument.
Sources
- NOAA NCCOS — Below-average summer 2025 dead zone measured in the Gulf, July 2025.
- NOAA NCCOS — Hypoxia research program.
- Delaware River Basin Commission — Review of dissolved oxygen requirements of key sensitive species, November 2018.
- VIMS — Chesapeake Bay dead zone report, December 2025.
- Diaz & Rosenberg, Science — More than 400 dead zones worldwide, 2008.
- NOAA Fisheries — The untold story of harmful algal blooms.
- Alvarez et al., via Newsweek — Florida's losses from red tide, January 2024.
- Reviews in Aquaculture — Global fish-killing harmful algal blooms, 2024.
- HELCOM — Inputs of nutrients to the Baltic Sea, indicator update 2025.
- Hypoxia in the Baltic Sea: biogeochemical cycles, benthic fauna and management, 2014.
- NOAA PMEL — What is ocean acidification?
- NOAA Ocean Acidification Program — Acidification is more pervasive than previously thought.
- NOAA NCCOS — Nanobubble ozone technology and ballast water invasive species, July 2020.
- IMO — Implementing the ballast water management convention.
- NOAA GLERL — Great Lakes Aquatic Nonindigenous Species Information System, 2019.
- WHO — Microcystins background document for drinking-water guidelines, 2020.
- Fleming et al., via PMC — Aerosolized red tide toxins and asthma.
- California Department of Public Health — Domoic acid fact sheet.
- Harmful Algae — The 2001 Kuwait Bay fish kill.
- NOAA and the International Coral Reef Initiative — The fourth global coral bleaching event, 2024–2025.
- FAO — The state of world fisheries and aquaculture 2024.
- OECD — The ocean economy to 2050, March 2025.
- OECD — The ocean economy in 2030, 2016.
One water body at a time
Which of these is actually yours?
Most people who write to us name two or three and turn out to have one. Send the water body, what goes wrong in it, which months, and what a bad season costs — we will tell you which heading it belongs under, including when the answer is that we are not the right instrument.