Skip to main Content

Mysterious brown algae clouding Alaska's Kachemak Bay, identity unclear

  • Author: Naomi Klouda
  • Updated: May 31, 2016
  • Published October 6, 2013

A brown sludgy plankton bloom slogging into small bays that rim Kachemak Bay is raising concerns about how it may impact the delicate filtration systems of shellfish and other marine life. The plant life is described as four or five feet deep in concentrated areas.

Marion Beck, owner of the Saltry Restaurant in Halibut Cove, said it can appear foamy, accounting for the milky appearance of the water surface.

So far, this plankton from the group Gymnodinium is thought to be more of benefit than a harm, but scientists won't be sure until they can have it analyzed in a National Oceanic and Atmospheric Administration (NOAA) lab in North Carolina. Kris Holdereid, the NOAA manager of the Kasitsna Bay Laboratory on Jakolof Bay, was in the middle of an inquiry about the root-beer-colored plankton bloom before the U.S. federal government shutdown called by sequestation stopped his efforts.

"I am not allowed to work on it, not even to volunteer to keep studying it," Holdereid said. The phenomenon was noticed a week ago during the routine water-monitoring program conducted each summer in the bay. NOAA water monitoring biologist Dominic Hondolero and Holdereid were tracking, collecting samples and photographing them under a microscope in order to document it. The photo samples would then be sent to an Outside lab for identification.

"It turns the water brown, like when we had the red water from the red plankton bloom -- only brownish, indicating an abundance of that particular bloom," Holdereid explained. Fishermen and oyster farmers had called agencies expressing concern. Clem Tillion, an Alaskan icon from Halibut Cove and 60-year resident, said he's never seen such a breakout -- but believes it's not harmful. "Algal blooms gives our oysters and waters nutrients. Clear water has no life," Tillion said. "This isn't necessarily bad, but it's more than we've normally seen. I've never seen this much algae. It's one of the biggest localized blooms."

Tillion counted four toxic red tide events in Halibut Cove waters over the past 60 years. None were caused by a brown plankton. The monitoring program Holdereid has supervised for several summers seeks to discover how environmental conditions, water temperature, salinity and nutrients impact aquatic life. This baseline of data grows each season.

"We're trying to understand the patterns. Does it (plankton) help because you have food for oysters and clams? Plankton can also be toxic," she said. "A warm summer could have impacted it. We're going to try to tease that apart from the other data. We can't say conclusively right now. Between Kachemak Bay Research Reserve and NOAA, we've been monitoring and have more data now. That's kind of fun in helping to piece together an understanding."

The harm to an ecosystem could come when an algal bloom is so plentiful it causes the bundling of too many organics at once. When the plants die, they sink to the sea's bottom and decomposition eats up the oxygen that fish and other marine life require. "That's unlikely in this case, because here we see a lot of tidal circulation," Holdereid said.

The challenge in Kachemak Bay is understanding how all the pieces fit together. Using the sun's energy, small animals like zooplankton absorb lots of food and grow larger. "Small fish like eating those. Everything likes eating the rich phytoplankton. When it blooms it benefits many other things. At the same time, if there's too much, you could have low oxygen in some areas," she added.

As part of the federal government shutdown, NOAA is banned from continuing the plankton inquiry for now. But the Kachemak Bay Research Reserve is still on the job. They conduct routine phytoplankton sampling with residents all around the Bay contributing water samples. KBRR is a hybrid agency made up of the Alaska Department of Fish and Game and NOAA. Because it is administered by a state agency, its employees are not part of the furlough.

Still not identified

Harmful algal bloom program coordinator Catie Bursch, who works for Kachemak Bay Research Reserve, heads up the sea-water monitoring project. She was alerted by her monitors to the problem about the same time Holdereid and Honolero noticed it. The brown tidal plankton is covering a broad area from Bear Cove to Seldovia Harbor. Some species of this plankton group can produce foam, which may account for the milkish films on area waters when spotted from a plane.

"At this point, we can't get it identified to the exact species of plankton. The broad group of Gymnodinium is not on our list of toxin-producing phytoplankton, so at this point we are not concerned that it will affect human health," Bursch said, referring to shellfish that filter feed phytoplankton and then could be harvested by humans. Tillion said he and daughter Marion Beck were nervous when they saw the accumulation of brown stuff spreading.

"It's like fertilizer – too much can be deadly for your roses but a certain amount would be helpful. Once we did our investigation, I didn't feel worried about it," he said. Bursch said five people brought in samples from various bays for examination.

"Most of the calls came from Halibut Cove and Peterson Bay, but the bloom eventually has moved to the Homer side -- Bear Cove, Kasitsna Bay and Seldovia Harbor and probably other areas that we don't sample regularly," she wrote in an update for agencies. She attached a photo of the dinoflagellate responsible for the root beer-colored water. "Dinoflagellates are microscopic single-celled organism with a fast reproductive rate. They can become so numerous that they can change the color of the water," Bursch explains.

Bursch said she couldn't say for sure the plankton won't cause trouble in some way because they're so thick.

Jeff Paternoster with the Plankton Monitoring Network of NOAA was contacted about the bloom before the federal government shut down. He told Bursch not to send the samples yet; no one would be in the office to accept a UPS package. Paternoster looked at the photos and agreed with the broad identification, then was ordered home on furlough. Science has no choice but to wait for the politics to get sorted out.

"We will be sending samples to get identified with an electron microscope down to species when the federal government is back up and running," Bursch said.

Whatever the lumps of algae in Kachemak Bay are, the big hope is the bloom doesn't cause environmental damage in the meantime.

This story first appeared in the Homer Tribune and published here with permission.