---
title: a microbialite is not a water level
canonical_url: https://ensurance.app/guide/a-microbialite-is-not-a-water-level
markdown_url: https://ensurance.app/guide/a-microbialite-is-not-a-water-level.md
subtitle: the mound is alive when the water covers it
category: ecosystem-services
---

# a microbialite is not a water level

*the mound is alive when the water covers it*

A **microbialite** is a mound on the Great Salt Lake, built by microbes in the lake's own chemistry. You came for that word because a photograph looks like geology and the caption is about a lake in trouble. The mound is alive when the water covers it. The dark film on a submerged crown and the pale, pitted stone higher on the beach are the same mound in two conditions.

A microbialite is not a water level. A staff gauge is the numbered board someone reads to write down an elevation. The mound is not that board, and it is not a relic set out for its resemblance to an older Earth. On this lake the stone is still at work. The level is the permission. It is what lets the mat live.

A brine fly will not make a life on a flat beach of sand that keeps moving. The reason is the stone. It can wait until the film is in view.

## the film on the stone

At the north end of Antelope Island, reefs of these mounds stand in the shallows and, when the lake pulls back, on the shore it left. A railroad causeway splits the lake into a north arm and a south arm. The wind off the south arm smells like brine and mud that has been in the sun. Where the water still covers the reef, the working surface shows. Submerged, and at a salinity the mat can still work in, that surface carries a **photosynthetic mat**. From a distance it can pass for a stain. Up close it is the lake making food.

The PLOS Water paper "Desiccation of ecosystem-critical microbialites in the shrinking Great Salt Lake" puts a conservative figure on the work. Those mats conservatively contribute one third of the lake's **primary production**. Primary production is the first food the lake makes: photosynthesis on the stone. One third is the paper's careful share. Cover the mound and that share is in production on that stone. Leave the mound in the air and that stone's share dries with the mat.

Carie Frantz at Weber State and Bonnie Baxter at the Great Salt Lake Institute at Westminster University are among the authors of that paper. It establishes the food chain, and what drying does to it. On any given reef the question is whether the water is still over the stone.

## the fly, then everything else

The mats are the primary food of brine fly larvae. The flies are *Ephydra*, the brine flies that rise in a cloud when a wet reef is disturbed. The larva feeds on the mat. Most of the lake's floor is shifting sand and carbonate mud. The mound is the stable bottom in that moving floor. The flies need it in order to eat, and they need it in order to pupate. Table and nursery are the same object.

That is why the flat beach fails them. A beach moves. A mound stays where the microbes built it. The pupa needs the thing that stays.

Brine shrimp take the mats as a seasonal food. What they require of the lake is in [what brine shrimp need the lake to be](/guide/what-brine-shrimp-need-the-lake-to-be?from=guide). The mat is their seasonal table. This page stays with the stone.

The birds eat what the mats support. The Great Salt Lake is a Pacific Flyway stop because the flies and the shrimp are here to be eaten when the film is working. If you came with binoculars, the chain you are watching starts on a mound that looks like broken fill.

| what you are looking at | what it is doing |
| --- | --- |
| The dark film | Photosynthesis, one third of the lake's primary production when the mats are covered, the paper's conservative share |
| The mound | The stable bottom brine flies need for eating and for pupation |
| The birds | Eating what the mats support |
| The elevation | The condition that keeps the film underwater |

## a reading is not the reef

Falling water dries the mats. The level drops, the crown meets the air, and the film that was making food goes pale. A mound that was feeding larvae becomes the stone higher on the beach. Same mound. The condition changed.

On Wednesday, 25 September 2026, after the summer drop, the south arm stood at 4,189.7 feet and the north arm at 4,189.6 feet. Carter Williams reported both for KSL and the Great Salt Lake Collaborative. The same account placed the lake over 8 feet below the state's minimum healthy level, and a little more than a foot above the 2022 record low. Those are elevations. The mat on any single mound depends on whether that mound is still under water.

The lake those feet belong to is [what the great salt lake actually is](/guide/what-the-great-salt-lake-actually-is?from=guide), a terminal lake. The Bear, the Weber, and the Jordan end here. Nothing carries them on to a sea. What they deliver is the water that can cover a reef, for as long as it remains deep enough to do it. A dry year moves the elevation. Water used upstream moves it too. The mound receives the lake.

Picture the same afternoon twice. In one, the crown in front of you is dark, the flies lift, and the mat is making food. In the other, the crown is pale and the film has dried. You can see both on a single walk from wet stone to dry stone at the north end of the island, whenever the lake has drawn a line between them.

:::johnson
**cover the mound, and the water that reached this lake is still at work.**

The elevation is a condition. The mat is the living thing. Water over the stone is how the lake keeps making food.

[the lake's place →](/great-salt-lake.basin?from=guide)
:::

## who already holds the elevation

Hannah Freeze holds the Great Salt Lake Commissioner's Office. Lindsie Smith directs the Great Salt Lake Alliance. John Luft manages the Great Salt Lake Ecosystem Program, which already watches the brine shrimp harvest on this water. The mat sits upstream of that harvest.

The Wednesday of those elevations was also the day the Alliance and the Commissioner's Office released their Solutions Exchange report. The exchange was held 22 June 2026. Forty-seven organizations took part. The next steps they named are solutions-focused education, better access to implementation information, and folding the findings into state planning. The architecture is already there. The Commissioner, the Alliance, and the Ecosystem Program are the heroes of that work.

A second layer of funding can sit beside them, beside the state's lease, beside the trust, and beside the harvest. The Great Salt Lake, its brine shrimp, and its microbialites exist whether or not anyone buys a certificate. [*Ensurance*](/great-salt-lake.basin?from=guide) funds that condition. It is not the lake.

Under the live place agent, **brine hold** is a line in ideation: [co-create it](/specific/create?mode=suggest&agent=great-salt-lake.basin&name=brine%20hold&from=guide); a person reviews it; the parent agent receives it. The line would fund the lake's condition, water over these mounds included, held next to the programs already in the field. The mat remains a living surface. The line funds the condition that keeps it at work.

## if this shore is already yours

If you steward a wetland, a refuge edge, or any ground whose water can still reach the lake, the film is downstream of your choices even when the lakebed is not on your deed. The mound has a mat, or it has a pale crown, depending on whether the water stayed.

If you have walked the north end of Antelope Island and watched the dark tops give way to dry stone as the water withdrew, you already know the difference this page is naming. That walk is the case for getting water back over the reef.

If you read elevations for a city or for the state, the gage is your instrument and the mat is why the number matters. The readings describe the water the film still needs.

See the place account that stands for the lake, [great-salt-lake.basin](/great-salt-lake.basin?from=guide). If the mound is the reason you came, [talk with someone about keeping water on it](/contact?from=guide&topic=great-salt-lake). Then read [what brine shrimp need the lake to be](/guide/what-brine-shrimp-need-the-lake-to-be?from=guide). Their season runs through the same cover.

The pale stone and the dark one are one reef. The question they ask is the same question every time you visit. Is the water still on it?

## frequently asked questions

### what is a microbialite?

A microbialite is a carbonate mound built where microbes interact with a lake's chemistry. On the Great Salt Lake, a mound that is submerged at a workable salinity carries a photosynthetic mat on its surface. The mound is at work in the present whenever the water covers it.

### is a microbialite the same thing as the water level?

A microbialite is the mound. The water level is an elevation in feet, the kind of number reported for the south arm and the north arm. They meet in one decision. The level determines whether the mat is underwater. Read the mound as a living surface, and read the gage as the condition that surface requires.

### what do great salt lake microbialites support?

When the mats are submerged and the salinity is workable, they conservatively contribute one third of the lake's primary production, according to the PLOS Water paper. They are the primary food of brine fly larvae. The mounds are the stable bottom those flies need in order to eat and to pupate. Brine shrimp use the mats as a seasonal food. The birds eat what the mats support. Lose the film and that chain loses its first table.

### what happens to a microbialite when the lake drops?

Falling water dries the mats. That desiccation is the paper's subject. A lower elevation puts more crowns in the air, and the fall dries the mats on those crowns. The fact that matches the mound is whether the stone is still covered, at a salinity the mat can work in.

### who is already doing this work?

The Commissioner's Office, the Great Salt Lake Alliance, and the Great Salt Lake Ecosystem Program already coordinate the lake's condition. Hannah Freeze, Lindsie Smith, and John Luft lead those offices. The public account of the mounds as food and habitat is the PLOS Water paper by Carie Frantz, Bonnie Baxter, and their coauthors. The move that matches their work is to keep water over the reefs, beside the programs already responsible for the elevation.

## sources

[Desiccation of ecosystem-critical microbialites in the shrinking Great Salt Lake, Utah (USA)](https://journals.plos.org/water/article?id=10.1371/journal.pwat.0000100) — PLOS Water, Frantz and colleagues, published 12 September 2023. Photosynthetic mats when submerged at a workable salinity; a conservative one third of primary production; primary food and pupation habitat for brine flies; seasonal food for brine shrimp; birds eat what the mats support; falling level dries the mats.

[Many groups are trying to save the Great Salt Lake. Here's how they can better collaborate](https://www.ksl.com/article/51627764/many-groups-are-trying-to-save-the-great-salt-lake-heres-how-they-can-better-collaborate) — KSL / Great Salt Lake Collaborative, Carter Williams, 25 September 2026. South arm 4,189.7 feet, north arm 4,189.6 feet, the healthy-level comparison, the 2022 comparison, and the collaboration report released that day.

[Great Salt Lake Solutions Exchange report identifies opportunities to strengthen Utah's lake solutions](https://greatsaltlake.utah.gov/updates/great-salt-lake-solutions-exchange-report-identifies-opportunities-to-strengthen-utahs-lake-solutions/) — Commissioner's Office release. Exchange held 22 June 2026; 47 organizations; the report's next steps.

## the series

This is one of six pages on the lake.

- [what the great salt lake actually is](/guide/what-the-great-salt-lake-actually-is?from=guide)
- [what brine shrimp need the lake to be](/guide/what-brine-shrimp-need-the-lake-to-be?from=guide)
- [a microbialite is not a water level](/guide/a-microbialite-is-not-a-water-level?from=guide)
- [great salt lake dust is the lakebed](/guide/great-salt-lake-dust-is-the-lakebed?from=guide)
- [the bear, the weber, and the jordan](/guide/the-bear-the-weber-and-the-jordan?from=guide)
- [who already sends water to the lake](/guide/who-already-sends-water-to-the-lake?from=guide)