Algae studies not just for geeks

[USA] It’s interesting how what passes for geekiness changes over time.

Consider the once unhip phycologist, a biologist specializing in the study of algae.

Just a few years ago, most adults would sooner watch TV in their parents’ basement than be cornered at a party by a tipsy phycologist expounding on the difference between microcystis and microcystin. But no more.

These days, the phrase “algal bloom” is on everyone’s lips, and there are calls from all quarters for additional research into the Great Lakes’ worrisome algal problems.

I’m not a phycologist — if only I were so cool — but I thought it might be interesting to share a few general observations on what biologists mean when they talk about algae.

Let me pick my words carefully here. You will not find a very satisfying definition of the term in Wikipedia, a modern dictionary, or indeed in any current biology textbook.

Here’s an example from the Smithsonian Museum’s website: “Algae are photosynthetic organisms that occur in most habitats. They vary from small, single-celled forms to complex multicellular forms, such as the giant kelps that grow to 65 meters in length.”

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That description covers so much turf that it’s not very useful.

Actually, the idea that there exists a group of organisms you can logically categorize as “the algae” is an antiquated concept, a holdover from the earliest days of biology when taxonomists’ understanding of the diversity of life on the planet was much simpler than we now know it to be.

Back in the day, we used to think that living things could be divided into five kingdoms: Animals, Plants, Fungi, Protists (unicellular organisms) and Bacteria.

The Protists were said to mostly consist of animal-like forms such as amoebas, and plant-like forms called algae that could do photosynthesis.

That sort of worked OK for tiny one-celled units like diatoms, but what about seaweeds and giant kelp that are clearly multicellular yet are still commonly referred to as algae? And then there’s the whole issue of the cyanobacteria, which are widely known as the blue-green algae but are more akin to bacteria than to the “real” algae.

Biologists abandoned the five Kingdoms model of life some years ago as modern genetic methods revealed a much more complex picture.

For one thing, while we used to group all forms consisting of cells without nuclei (and various other structures) into Bacteria, we’ve since learned that these ancient organisms consist of two very different categories of lifeforms, one group we still refer to as Bacteria and the other as Archaea.

Everything else — made of cells that do contain the organelles you learned about in fifth grade — is placed into Eukarya, which is divided into four supergoups whose names I won’t inflict upon you.

As it turns out, the many eukaryotic organisms biologists have traditionally referred to as algae are widely scattered across three of those four supergroups.

Take-home message: Biologists still use “algae” because it’s so entrenched in common speech. But it’s largely a term of convenience; there are worlds of important differences between the various groups that people loosely refer to by that name.

Oh well. So then, what about that microcystis and microcystin thing? The stuff that’s causing most (but not all) of the problems in the western end of Lake Erie, Grand Lake St. Marys and other bodies of water throughout the northeast belongs to the subgroup of the bacteria domain mentioned above — the cyanobacteria, often referred to as the blue-green algae or just the blue-greens.

Three genera of blue-greens cause most of the trouble: microcystis, anabaena and aphanizomenon.

When the lake’s waters get late-summer warm and there’s plenty of nutrients (especially phosphorus and nitrogen) around, long strings of blue-green cells reproduce so well they create shimmering green “algal blooms” dense enough to be seen by satellites.

What turns a bloom into a hazardous algal bloom (HAB) is that, under certain, not well-understood circumstances, some species of blue-greens produce cyanotoxins — poisons such as microcystins, anatoxins and others that pose serious health risks if ingested.

Unfortunately, in part because heavy rains this year washed so much fertilizer into the lake, the National Oceanic and Atmospheric Administration is warning of even worse August HABs in Lake Erie’s Western Basin than occurred in 2014.

On the plus side, a lot of effort has gone into creating a much improved system for monitoring algal and cyanotoxin conditions in the lake since microcystin contaminated Toledo’s drinking water system last year, and cities bordering the basin are continuing to beef up their ability to screen for and remove toxins in their water treatment plants.

 

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