Climate Change and Aquatic Collecting

    Richard L. Howey, Wyoming, USA

 

If you’re a climate change denier or don’t accept the fact that humans are a significant factor in that process, then you should probably stop reading right now. An international report just released (February 28, 2022) paints a very grim picture of what is happening to the climate right now–not 25 years away, not 10 years, not 2 years, but right now! Perhaps the most immediate and pervasive effects are economic ones which are already having direct impacts on approximately 3 billion people and indirect impacts on the remaining 6 billion. These effects are increasing on a daily basis and there is no simple immediate means to reverse or even slow them significantly. In fact, there may be few long term means to even slow these processes now that they have begun. Glaciers melting, sea levels rising, severe droughts, unprecedented wildfires, increased hurricane and tornado activity, the destruction of large sections of marine reefs, severe winter storms which can bring bitter cold, heavy snows, or drenching rains and flooding–and this is just a brief catalog. It doesn’t even begin to take into account the consequences for agriculture, fishing, air pollution, and larger and larger areas of habitat destroyed by humans for “development”.

You can read about all of these things or hear about them on the news. I want to concentrate on a much smaller issue, a personal and selfish one; namely, the effect of climate changes on collecting samples for the microscope from ponds, rivers, lakes, and tidepools. I live in a high plains area at 7,200 feet and surrounded by mountains that reach 12,000 feet. It is very rich in both fauna and flora and when the waters thaw, there is an incredible bounty micro-wise. However, the last 10 to 15 years, I have noticed distinct changes. We have had a prolonged drought and this has meant higher water temperatures. Thermal increases pose a special problem when, in relation to shallow ponds and lakes, one considers that the high altitudes already mean high levels of ultraviolet radiation. Furthermore many of the lakes and ponds out in the high prairie are highly alkaline and increased evaporation from drought and higher temperatures means that the concentration of alkaline salts increases significantly, creating environments in which relatively few protists and other small aquatic fauna and flora can survive. Fertilizer that flows off fields into the bodies of water in the area increases the problem by providing an overly rich nutrient “soup” in which certain kinds of bacteria, algae, and cyanobacteria not only thrive, but produce intense blooms.

For the last 8 or 10 years, several lakes in the high plains here have reported severe cyanobacterial blooms such that warnings were issued regarding potential toxicity to pets, livestock, fish, and wildlife. At least one instance of the death of a dog was recorded.

Two of the major cyanobacterial blooms reported were due to the following organisms:

1) Aphanizomenon flos-aquae (a name to warm the cockles of a taxonomist’s heart). I first encountered this organism during a midsummer bloom at Crystal Lake In Curt Gowdy State Park. I drove down to the site on a rough dirt road from Granite Lake above. Fortunately, at the time, this was not a highly developed recreational area and so it was usually visited only by the occasional fisherman. This meant that pets and children were not as likely to be exposed to this potential danger. However, it had already been recognized that there was some danger both at Granite and Crystal Lakes as they had both been posted with “No Swimming” signs.

I was very surprised at what I saw as I got close to the shoreline of Crystal Lake for, it appeared that the shoreline had been covered with green paint. Then, I noticed that the surface of the water had the same appearance. I quickly took out 3 collecting jars, my long-handled pole to which I had attached a small net for collecting samples. I handled the jars carefully as I already had a suspicion that this was a toxic bloom. Here are 3 images from Google. From this first one you can imagine that a great swath of such green would indeed look like spilled paint.

This next one fits another description which is also quite apposite; several investigators have described it as looking like bits of freshly mown grass.

The third one is a closeup showing the arrangement of the cells along the filament.

2) The second major blooms reported were caused by Dolichospermum lemmermannii (formerly know as Anabaena–the taxonomists strike again!). I’ll show you 2 images (from Google) of this organism. This first one exhibits 2 loose coils connected by a single, clear sphere known as a heterocyst, which fixes nitrogen.

The second image shows a long mass of dense filaments consisting of vegetative cells and also 2 heterocysts.

At the time, I was having camera problems and was unable to get images from my 3 samples. However, after 2 weeks, having solved the camera problem, I ventured back up to Crystal Lake in the hopes that the massive blooms would have subsided leaving some interesting results of their invasion. This turned out indeed to be the case and I was able to get some interesting samples and some images, but they were not quite what I had expected. Apparently, the blooms had caused other filamentous algal forms to exhibit some odd structural alterations. What I noticed first was some filaments which had diatoms attached to them, which was not really so unusual, but the filaments looked odd; packed and not exhibiting any usual cellular structure.

A second view of another clump convinced me that I needed to take a closer look

A closeup revealed that at least some of the filaments contained diatoms within, which I found quite surprising.

An even closer look revealed, in the upper filament, masses of diatoms and, in the lower filament, apparent structural alternation which needed yet closer examination.

So, a closer examination of what appeared to me to be an anomalous filament revealed what you will see below. I am by no means a specialist in algae, but my previous investigations presented filaments which were largely consistent in their replication of cells. These seemed altered and displaced. The first image is Differential Interference Contrast and the second is an inversion of the first.

Anabaena produces several different types of toxins and in low concentrations can produce gastrointestinal problems. High concentrations can cause serious neurological damage.

I have almost ceased to be surprised at what human beings will attempt and there are supplements that contain Aphanizomenon flos-aquae. Toxins are released when the cells die and can cause damage to liver tissue and cause nerve disorder as well. There are reputedly toxic and non-toxic forms of this organism and it is grown in the wild for use as a supplement; however, such aquiculture opens the possibility for contamination. Furthermore, I’m not sure I trust quality control, especially in aquatic environments in China, India, or Oregon; and even though it’s been used for centuries in Africa and South America, call me an old fuddy-duddy, but I’m suspicious of green gorp dragged out of lake, dried, packaged and sold for significant profit.

Changes in climate significantly affect the growth patterns of algae and cyanobacteria. These are remarkable organisms and many of them are highly adaptive and have much better odds of acclimatizing than we do. All around us there are indicators that these global alterations in climate are beginning to occur at levels that will, clearly and distinctly, alter the kinds of lives humans will be able to live in the very near future and these changes will become progressively more dramatic. What we need is a radically new kind of Manhattan project; a cooperative, global effort to unite our best and brightest thinkers to find innovative ways to create a new model of human culture which is in harmony with the environment rather than the present model which is so often destructive and exploitative. The survival of humankind will very likely depend upon whether or not we can mature sufficiently to transform ourselves. This is not mere idealism; it is the necessity for survival.