November 8, 2018
Shinrin yoku is the Japanese term for ‘forest bathing’. The idea is that when a person spends time immersed in a forest, what they experience and sense provides improved physical and mental well-being. The Japanese have embraced shinrin yoku whole heartedly. They have now dedicated 48 “Forest Therapy” trails so that everyone can have access to a forest, and their national forest agency has funded around $4 million into research about forest bathing.
Florence Williams book, The Nature Fix: Why Nature Makes Us Happier, Healthier and More Creative, peaked my interest in shinrin yoku. Then a bit of internet research revealed a growing trend toward forest bathing in the United States. In fact, the Association of Nature and Forest Therapy (Santa Rosa, CA) is currently training practitioners to guide forest therapy programs around the country. More locally there was a practitioner located in Kansas City, Michael Beezhold, and he was already a linkedin contact of mine. The two of us have a common friend in Carbondale, Illinois. Michael was conducting some forest therapy walks over the next few weeks. So, October 28, my wife, Sharon, and I found ourselves on the road to Kansas City to participate in shinrin yoku.
During a forest therapy walk, the participants strive to immerse all five senses (sight, hearing, feeling, taste and smell) into the experience of the forest. By focusing everything on the walk, other concerns and distractions go by the wayside. It might be thought of as a guided meditation. We started our forest therapy by sitting in a small clearing for a few minutes. There were nine of us in all. Michael asked us to just pay attention and note what we experienced. After we sat long enough to clear our minds, we then shared those experiences. My initial response was noting the way gusts of wind moved through the forest. Others noticed sounds, the coolness, the feeling of their bare feet on dirt etc. We spent about 15 minutes on this ‘invitation’. Our next experience was to walk slowly through the forest to a second gathering place. Michael encouraged us to get off the trail, pay attention to smells and tastes, make mental notes of what we saw. It took about another 15 minutes to walk the quarter mile down to the second clearing. There we sat again and share our experiences during the walk.
After another 15-minute walk we stopped at a small stream. It was surprisingly clear and fresh for an urban stream. Michael referred to these stops as ‘invitations’. We were invited to look at the surface of the water, then to look at the streambed, then we felt the surface and finally we pushed down our into the water and finally just listened. Once again, we were invited to share our feelings.
Our last invitation was a traditional forest bath. No, we didn’t remove our clothes and dive in! A forest bath is merely finding a quiet place in the forest to sit and listen, smell, feel, taste or see. We broke up our group and each headed out on their own. The bath lasted possibly half an hour. By now I had totally lost track of time. Then when Michael blew the whistle, we re-emerged from the forest and came together one more time. That time we raised a toast to the forest using an infusion of pine and spruce needles in water. It really didn’t taste all that bad. Most of us hung around a talked a bit, then walked back to our cars. Over the afternoon, the walk may have covered a mile or less.
There is no defined outcome expected form forest therapy. Sharon and I agreed that it was a relaxing afternoon and that we felt refreshed. Research shows that participants in forest therapy as a group have significantly lower blood pressure, a slower pulse rate, less cortisol (a stress hormone) in their system and a decrease in sympathetic nerve activity after the experience compared to prior to the therapy (See Florence Williams book or check out the scientific papers posted on the Association of Nature and Forest Therapy’s website, https://www.natureandforesttherapy.org/about/science). Other research indicates that regular forest therapy alleviates depression, attention deficit hyperactivity disorder and Alzhteimers (https://www.scientificamerican.com/article/why-getting-away-in-nature-is-good-for-your-mental-health/). Why forest therapy works is still a field for study. According to Williams, researchers are looking into an aroma therapy type of response to chemicals in the forest air and soil, a response to the diversity of the microbiome in the forest, a response to the relaxation effect or just to getting away from stress for a while. Hendriksen’s article mentioned above gives several theories related to the improved metal health documented in participants. Those theories include reduction of attention fatigue, evolutionary remnants from our history as a forest species, and what was called ‘soft focus vs. hard focus’. Hard focus is what you experience driving in heavy traffic or playing video games. Soft focus is what you experience gazing at a stream or mountain. During soft focus, your mind has free time to heal itself. Not being a neuroscientist, I can’t claim to know which theory is best. My expectation is that it is some combination of all of the above and it will be very hard to single out a single cause.
Shinrin yoku is a positive step toward maintaining a healthy and reduced stress lifestyle. After participating in Michael’s walk, I realize that I have been practicing shinrin yoku my whole life. I just didn’t have a good name for fooling around in the woods. Hopefully I can keep at it for several more years.
Last weekend in Northwest Arkansas we had our first real taste of fall weather. Temperatures dropped from the low 80’s into the 40’s and even 30’s. Then a misty rain and a breeze came along and provided a perfectly miserable couple of days. This cold snap is a reminder that our trees will soon start turning and then shedding their leaves for the winter. We are all set for three to four weeks of glorious color followed by a blizzard of falling leaves.
At the Morgan house, we can let leaves lay where they fall in the back of our lot. That practice provides cover for insects through the winter and as a result food for over-wintering birds and other small animals. The leaves also return valuable carbon and nutrients into our soil for the next season. However, neighborhood convention is that lawns be cleaned of dead leaves to keep up a neat appearance. So, we go along with the neighbors. The leaves from our lawn are collected and chopped up. The first group is used to fill the compost bin that has become depleted over the summer. The rest are put into wire cages and allowed to age for a couple of seasons. Eventually, Sharon spreads that leaf mulch in her native plant beds. No fertility is allowed to leave the property. If we are lucky, we even get some of our neighbor’s leaves that blow up against our fence.
Beyond providing for a few weeks of color and sightseeing, leaf fall is an important event for both the terrestrial and aquatic ecosystems. Leaf fall is a part of cycling of minerals and nutrients through our ecosystem. An idea of the importance of the event is simply the mass of material that is involved. Take the Ozark National Forest as an example. The forest covers roughly 1.2 million acres (https://www.stateparks.com/ozark.html). To simplify this calculation, I am assuming that the forest can be characterized by Red Oak. That is not a good assumption, but it will provide an order of magnitude estimate. Next assume that 75% of the area in the forest is actually forest. Leaf area index is the ratio of the surface area of the leaves on a tree (one side only) to the surface area of the ground covered by the tree’s spread. Breda (Journal of Experimental Botany, Volume 54, Issue 392, 1 November 2003, Pages 2403–2417,) estimated the leaf area index for a Red Oak in a dense forest as 4 to 4.5. So for every acre of trees, there are 4 to 4 ½ acres of leaves. The weight of Oak leaves according to Jurik (Amer. J. Bot. 73(8): 1083-1092. 1986.) is around 40 grams per square meter. Doing a little math to convert everything to metric and multiplying, it turns out that just shy of 600 million kilograms (1.3 billion pounds) of leaves fall in the Ozark National Forest each autumn. Those leaves may be up to 13% protein (https://www.fs.fed.us/database/feis/plants/tree/querub/all.html). Rounding to 10% protein and multiplying, it is found that 60 million kilograms (130 million pounds) of protein fall within the forest each year.
Given the mass of material falling as leaves, it is not surprising that leaf fall is a significant source of energy in forested ecosystems. For headwater streams (those near the streams source) in forested watersheds, leaf fall may be critical to the energy balance for the entire year with respect to the aquatic community. In those streams the forest canopy covers nearly the entire stream blocking sunlight. With little direct sunlight reaching the stream, there is little photosynthesis taking place within the stream. Leaf fall into the stream makes up the shortage. The leaves provide a source of carbon, nutrients and minerals to the stream system. Vannote et al. (Canadian Journal of Fisheries and Aquatic Sciences, 1980, 37(1): 130-137) noted this relationship in their 1980 paper, the River Continuum Concept). It was pointed out in the paper that stream ecosystems could not be studied simply on a square meter basis like lakes. Streams flow. So it is necessary to consider where along the continuum of the stream the square foot being studied existed. Headwater streams, without photosynthesis were dependent upon material falling into the stream from the watershed, primarily leaves and woody debris, for energy.
When leaves fall into a stream or other body of water, they are quickly colonized by fungi and micro-organisms which start the decomposition process. As the leaves decompose, they become more palatable and soon macroinvertebrates (bugs) start munching. Those bugs are then eaten by larger organisms in the familiar food pyramid. Left over parts from the leaves and waste products from the bugs and fishes drift on downstream helping to support those communities as well. Leaves then are a critical part of the nutrient and carbon cycling in streams.
Good streamside management maintains a healthy forest in the riparian zone. In headwater streams especially, that forest helps to maintain a healthy stream including reinforcing the streambanks and providing for the aquatic community. Healthy streams are better able to process nutrients and provide us all with clean, dependable water.
October 10, 2018 is the date of the fourth annual ‘Imagine a Day Without Water’ campaign. Water is such a given factor in our daily lives that it is hard to imagine going without. Water is also so convenient, most of us never give it a thought, just turn the tap and out the water comes. So here is my attempt to imagine a day without water. I am assuming that this is a day without potable public water. How this happens is unknown, possibly a massive break in the main from the water treatment plant into town and simultaneously all of the storage tanks failed and drained. Whatever the situation, water in my scenario is not delivered to my house, or any house in the city.
It’s 3:15 AM. As usual I have to get up and pee. It’s not a big deal, I walk down the hall, do my business and flush. Everything works like normal. As I wash my hands, I notice that the water pressure is low. It’s no big deal, I can look into it in the morning. So, I go back to bed.
Now it is 5:15 AM, my normal wakeup time. My routine for getting up is to go to the bathroom, then make coffee and during the summer I move out to the porch and watch the sun come up. There is no water in the toilet. Well now, that is a problem. Luckily, we live at the edge of town, I run out behind the quince bush and do my business. In the kitchen I get my coffee pot ready. Nothing comes from the tap. That means no coffee this morning. Maybe when Sharon gets up we can run down to the local coffee shop.
At 5:45 AM, Sharon gets out of bed. She goes into the master bath and uses the toilet. The toilet flushes like normal, but then there is no water for her to wash her hands and the toilet doesn’t refill. I tell her that ‘They’ are likely working on the water line down the street and will have things back to normal soon. We have some cereal with soy milk then head down to the coffee shop for our morning fix. Sharon mentions that there doesn’t seem to be anyone working on the water main. I assure her that it must be just around the corner out of sight. When we get to the coffee shop, there is a sign, “Closed, No Water”. There is another coffee shop across town so we drive over there, same situation. We head back home resolved to get through the morning with no caffeine. Back home, scrolling across the bottom of the TV screen is a list of schools, churches, factories and businesses closed for the day because of the water outage. The newscaster says that it might be several hours until the situation is under control. Since we are both retired, that isn’t a real big deal, at least I can do some work around the house. Sharon wonders how this affects all those people working in the factories. I respond that they likely get the day off with no pay. Then head out to the yard. A couple of tarps and a cat hole creates a makeshift latrine. At least we have some privacy. The grass was getting tall so I decided to mow the yard.
Sometime around 11:30 AM there are sirens blaring. I wonder what is up. It is close to lunch time so I move inside. I am pretty gritty and hot. But there is no chance to take a shower. We have some cheese sandwiches with lettuce. We are taking a chance by using lettuce that is not washed but maybe we won’t be infected with E.coli bacteria. The guy on the TV says that a fire is burning in a house across town. That explains the sirens. Then he goes on to say that when the fire fighters arrived, there was no water. The house burned to the ground.
It has been a while since I washed the car. My plan had been to wash it this afternoon. But with no water, that gets put off a few more days. I spent the afternoon inside reading.
We had supper at home tonight. It was a frozen entrée because there was no water for cooking. Also, there was no iced tea or coffee. We couldn’t wash our hands so we wiped off as best we could. Overall supper wasn’t that bad except we couldn’t brush our teeth. Those teeth felt pretty gritty the rest of the day. I wandered out to the temporary latrine one more time. After working in the yard all day, a shower sure would feel good. But there is no water, I can’t even sponge off. Sleeping will be difficult.
According to Statistica.com, the value of wood and paper shipments from mills in the United States during 2017 was $282 billion. The industry supported 953,000 jobs with a payroll of $53 billion (https://www.statista.com/statistics/252844/us-industry-shipments-value-of-the-forest-products-industry-2012/). That is the economic value of the forestry industry but forests provide much more than wood and paper to our society.
Ecosystem services are the many and varied benefits that humans freely gain from the natural environment and from properly functioning ecosystems. The Millennium Ecosystem Assessment identified ecosystem services provided by forests as: nutrient cycling (returning nutrients to the environment for reuse), climate regulation, raw materials, erosion control, water treatment, recreation, food production, genetic resources, soil formation, water supply, disturbance regulation, water regulation, biological control, and cultural values (http://www.fao.org/docrep/w7714e/w7714e05.htm). During the year 1997 Robert Constanza attempted to put a value or those ecosystem services (nature. Vol. 387. May 15, 1997). He arrived at a value of $969 per hectare per year. Using the CPI inflation calculator for 1996 – 2018, the current value of Constanza’s estimate is $1588 per hectare per year. The total forested area in the United States during 2012 was 766 million acres or roughly 310 million hectares (https://www.fia.fs.fed.us/library/brochures/docs/2012/ForestFacts_1952-2012_English.pdf). So, by multiplication the value of our forest comes out to be 492 billion dollars per year, a little over 2 1/2 % of the US Gross Domestic Product for 2017 (https://tradingeconomics.com/united-states/gdp). These are not actual dollars, but if the forest was lost we would have to find those dollars to replace those free services.
As impressive as these figures are, they still don’t represent the entire value of our forest land. There is a large and increasing body of literature that shows beneficial effects of exposure to forest ecosystems on our health, social, and cognitive well-being. In her new book ‘The Nature Fix’, Florence Williams delves into these aspects of forest’s value (W.W. Norton & Company. New York). Williams interviewed researchers looking into the value of forests and in many cases was able to participate in the research herself. The data show when people are exposed to forests, heart rate drops, blood pressure goes down, stress is reduced, immunity to disease is increased and mood improves. Researchers, according to Williams, are not yet fully sure what drives this correlation. Scientists are looking into several possibilities including: exposure to the immensely diverse microbiological community of the forest; an aroma-therapy type response to chemicals that trees exude; or possible human evolution in a forest environment and natural relaxation when they return. Nevertheless, the effect is real. In fact, Japan and South Korea have started dedicating forest therapy units in their public forests to take advantage of the benefits. Closer to home, a study by Donovan et al in 2013 (available at: https://www.researchgate.net/publication/234697703 looked at death trends from cardiovascular and lower respiratory disease before and after infestation by the emerald ash borer infested the mid-west. According to Donovan, the loss of ash trees in the infected area resulted in approximately 21,000 extra deaths up to 2007. Those 21,000 deaths definitely had both economic and social value in the infected area.
With respect to the cognitive value of forests, we can look at Florence Williams discussion of Kindergarten. Kindergarten is a German term meaning ‘Garden for the Children’. During the year 1837, Freidrich Fröbel established the first Kindergarten. Fröbel’s idea was that the children would learn by absorbing the natural world with all of their senses. Through play in the woods, they would intrinsically learn the laws of geometry, form, physics and design despite themselves. After a few years, The Prussian government shut Fröbel down fearing a generation of free-thinking citizens. Can you imagine the impact a bunch of free-thinking kids could have on an authoritarian government! Nevertheless, the concept has endured. Today, Germany has over a thousand Waldkindergärtens or ‘Forest Kindergartens’. In these schools the students spend most of their day outdoors exploring nature and by extension learning the fundamental laws of science as well as getting along. The benefits are not confined to children. In a 1995 study ( willsull.net/resources/KaplanS1995.pdf) Kaplan found that contact with nature had a restorative effect on adults providing them with improved focused attention and reduced mental fatigue.
Forests do provide a wide variety of benefits including economic return, environmental services as well as providing for health and education. A managed forest need not consider only a single objective. Well managed forests could provide for all of these benefits over time. When looking at the economic value of ecosystem services such as those provided by forest, it is important to consider the values or improved health and cognitive ability.
I first read Out of the Earth during 2007. Sharon, my wife, was taking Soils from Dr. David Miller at the University of Arkansas at the time. Dr. Miller assigned Out of the Earth as required reading for the class. The book looked interesting, so I read it too.
Daniel Hillel was a professor of soil and water science at NASA’s Goddard Institute for Space Studies at Columbia University, New York. Out of the Earth is the story of mankind’s relationship to the soil and how our abuse, or respect, of the soil has ruined, or nurtured civilizations.
The book is written in five parts: For Soil Thou Art; The Nature of Soil and Water; The Lessons of the Past; The Problems of the Present and Unto the Soil Thou Shall Return. One might surmise from the title of the book and the different sections that Dr. Hillel was also a student of the Bible and the near East. You would be correct. Dr. Hillel grew up in Israel where he learned the old stories and how to apply those stories to his science. That background comes through loud and clear in Out of the Earth.
The first section, ‘For the Soil Thou Art’, sets the stage for humankind’s relationship to the soil by invoking the second chapter of Genesis, “God, Yahweh, formed man out of the soil of the earth and blew into his nostrils the breath of life …. God then took man and put him in the Garden of Eden to serve and preserve it.” This made man the steward of the earth. Hillel then relates how man abused God’s trust for short-term profit. Consequentially, man was expelled from the garden and cursed to work the earth.
‘The Nature of Soil and Water’, part 2, is a technical, but very readable primer on soil and water science. Hillel describes soil as:
“our earth’s primary cleansing and recycling medium, in effect a ‘living filter’ wherein pathogens and toxins that might other wise focus our environment are rendered harmless and transmuted into nutrient”
Water is described as, “the Vital Fluid” i.e. the primal constituent of all living organisms”. ‘The Dynamic Cycle’ gives a detailed description of the different components of the hydrologic cycle. Hillel then goes on to discuss how plants capture the energy of the sun and become the base of the earth’s food web in ‘The Primary Producers”. To wrap the section up, ‘The Tenuous Balance’ discusses the science of ecology.
Part 3, ‘The Lessons of the Past’ is the story of the agricultural revolution. Hillel guides the reader from the evolution of man (Homo sapiens sapiens) into man’s domestication of plants and animals and the introduction of agriculture. Then he goes on into the birth of civilizations. Along the way, Hillel goes into the farming methods developed by early farmers both in the Middle East as well as in Mesoamerica. More particularly, he looks into the development of irrigation and how early farmers enhanced fertility. Numerous examples of the ingenious farming systems employed by the ancient farmers are explored. Hillel then turns to the impact of those farming methods on the soil and water resources of the regions where they were employed. Mostly, early farmers understood neither the impact of rising water tables from excess irrigation waterlogging the soil, nor the build up of salt on soil where minerals are brought to the surface from ground water are left behind by evaporation. Eventually, fields then whole regions lost fertility. As a consequence, civilizations hat to reach out further and further for food and other resources. This reaching out lead to empire building. Eventually empires collapsed under the weight of bureaucracy and limited resources.
Part 4, ‘The Problems of the Present’ begins with a depressing statement:
“Each and every one of the insidious man-induced scourges that played a role in the deaths of past civilizations has its mirror image in our contemporary world. Salinization, erosion, denudation of watersheds, degradation of arid lands, depletion and pollution of water resources, abuse of wetlands and population pressure are still with us, but at an even larger scale. Added to the old problems are new ones undreamed of in the past centuries: pesticide and fertilizer residues; domestic and industrial waste including toxic chemicals; air pollution and acid rain; global climate change; and the wholesale extinction of species”.
From that start, Hillel gives examples of each problem with explanation of the processes in play.
Part 4 is the longest section of the book at 123 pages. It is not entirely without hope. Hillel does point out certain systems that have attained sustainability. An interesting example is China’s system of polyculture wetland utilization:
“These systems are based on the husbandry of livestock, flow, and freshwater fish in comp=bination with perennial and seasonally rotated crops…. Pigs and ducks, together with fish, provide each household with annual protein, and a small cash income; while aquatic plants, crop residues, and kitchen leftovers feed the livestock, the manure of which fertilize the fish ponds and promote growth of plankton – the principle food of carp” …. In these systems nutrients and energy are cycled continuously and little waste results”.
Another example is the micro irrigation system that has been implemented in Israel.
The final section, ‘Unto the Soil Shalt Thou Return’ starts with ‘A Global Accounting’. To be blunt, Hillel says we are in trouble bigtime:
“The environmental transformations we are witnessing are driven by a continuous and accelerating increase in population and land exploration. More people exploit more land, so it may then support more people, who must exploit more land, and so ad destructionem”.
Here, as opposed to the rest of the book, Hillel places blame, not on individuals nor even a sector, but on an economy where “development receives first priority and environmental considerations are subordinated components of economic endeavors”.
The book ends with a short chapter expressing conditional optimism. The path forward, he says, is there for us if only we, as a species, chose to follow. Out of the Earth is now 27 years old. Recent work by Hans Rosling (Factfulness) and Steven Pinker (Enlightenment Now) do present data that show trends toward better conditions both socially as well as environmentally. Possibly we have turned the corner.
Dr. Hillel has been one of my heroes for a decade now. I find Out of the Earth’ as relevant today as when it was written in 1991. It should be required reading for anyone who considers themselves educated.
Stream health is a term that is frequently used in the literature about streams. But health is seldom defined. The term makes an analogy to human health. Therefore, it does create a sense of stream condition that people can relate to. But it doesn’t really describe any particular state of the stream.
In the prologue of his very well researched and thought out book, ‘A View of the River’ (Harvard University Press, 2005), Luna Leopold makes it clear that the book is his view of the river, not an exhaustive treatise on the field of potomology (the study of rivers). This post is my very simplified view of stream health.
The World Health Organization describes health as ‘a state of complete physical, mental and social well-being’. That is a good place to start a view of stream health. It is likely streams have neither mental nor social well-being. I can’t really say that they don’t, but to be safe I will substitute physical, biological and chemical well-being. I do have some data on those characteristics.
With respect to physical well-being, streams have two basic functions: they transport water and they transport sediment. The amount of water transported by the stream, the stream’s discharge, is determined by the amount of precipitation in the stream’s watershed and possibly some contribution from groundwater. The amount of sediment is referred to as the stream’s load. Sediment is a product of erosion within the watershed as well as from the streams banks and bed. When a stream’s ability to transport sediment is equal to the amount of sediment provided by the watershed, then the stream is ‘in regime’. If the stream does not have capacity to transport the supply of sediment from the watershed, then deposition of sediment will occur. If the stream’s capacity is greater than the supply, then erosion occurs. When the stream is in regime, the stream flows along neither depositing nor eroding appreciable amounts of sediment. It will be a stable system.
A competent engineer can design a uniform channel that is in regime. That channel would flow along at a steady velocity and depth and sediment would gently bounce along the bottom. Little change would occur over time. The channel would also have few if any fish. Fish and the other members of the aquatic community need deep holes, shallow riffles, runs and glides. Different species occupy different environments. Our uniform channel needs some complexity to make the aquatic community healthy. A few engineers who are versed in fluvial geomorphology can design channels with rocks and other features put in just the right place to build in complexity and improve the aquatic habitat. Undescribed streams build in their own complexity. So, our healthy stream is in regime and also has complexity.
Biologically, my stream now needs a source of food for the aquatic community and a place for the citizens of that community to hide from predation. Where that food comes from depends on the location of the stream in the watershed. In the headwaters, streams are usually allochthonous (from without). The food washes in from the watershed or drops out of streamside vegetation in the form of bugs, worms and vegetative matter. Further downstream, where the stream widens and the canopy opens up such that sunshine hits the water, the food grows in the stream itself (autochthonous) in the form of algae. But nutrients (phosphorous, nitrogen, potassium) are still needed from the watershed to provide for growth. Again, the supply of nutrients needs to match the needs of the community. Too much nutrients and the stream gets fat, too little and it gets emaciated. A fat stream will likely get murky because of the algae content. And emaciated stream may be very clear but not have many fish. It’s a balancing act. However, like humans, streams will be in a better state of health on a lean diet. Then further downstream, the food mostly drifts down from above with the current (once again allochthonous).
The streamside vegetation is an important source of food for streams in the headwaters. Further downstream, the streamside zone also regulates the amount of nutrient reaching the water. So, streamside areas (riparian zones) are also important to well-being of the stream. Refugia from predation comes in the form of woody debris, rocks, cobbles, gravel and overhangs. This is frequently referred to by fishermen as structure.
The final characteristic of stream health is the chemical quality of the water. Water, even in a wilderness is a solution of many minerals and other compounds. In nature, the chemical characteristics of a stream are determined by the make up of the watershed that water flows through on the way to the stream and the chemical quality of the atmosphere that precipitation falls through. Most of the time, the stream will develop an ability to assimilate these minerals and compounds. In fact, a stream of distilled water would not be a healthy stream at all. The minerals and other compounds are necessary. When a chemical or other compound is added to a stream through point or nonpoint source discharges, the stream takes on the characteristics of those additions as well. If the stream cannot assimilate the addition, then it becomes polluted. Our healthy stream then must have a pollutant load less than the assimilative capacity.
In summary, my view of a healthy stream is one that is in regime (neither eroding nor depositing), has channel complexity, supports a diverse aquatic community with and adequate but not excessive nutrient supply, has a good cover of streamside vegetation, contains some structure and does not have an excessive load of chemical or organic pollutants. Such a stream should have a pleasant appearance, little nuisance vegetation, be a reliable source of water, and have good fishing.
June 17, 1793 Seaman John Carter on George Vancouver’s voyage of discovery along the coast of British Columbia died. A few days earlier Seaman Carter and some others ate fresh mussels that they collected in a cove along the coast. Within a few minutes, their lips and fingers became numb. The numbness progressed to paralysis. All but Carter recovered (https://www.leisurepro.com/blog/ocean-news/3-devastating-red-tide-events-world-history/). Years later it was determined that Seaman Carter had become the first recorded European to die from exposure to ‘the Red Tide” in the new world.
The Red Tide is an example of a phenomenon now known as a harmful algae bloom, or HAB for short. Algae are an essential component of the aquatic community. They form the base of the aquatic food chain. Normally algae are not a serious problem in a water body, or at worst, a nuisance. But under certain conditions some algae blooms can produce toxic compounds. Scientists don’t fully understand the conditions that create HABs. But there are lots of factors to be considered.
The National Oceanic and Atmospheric Administration (NOAA) describes a HAB as occurring ‘when colonies of algae — simple plants that live in the sea and freshwater — grow out of control and produce toxic or harmful effects on people, fish, shellfish, marine mammals and birds’ (http://www.noaa.gov/what-is-harmful-algal-bloom). The Red Tide is likely the best known of the HABs. The State of Florida is currently, as I write this in mid-August 2018, experiencing a severe Red Tide along its west coast. This August 13th the Governor of Florida issued an emergency order for the Red Tide. The order covers 7 coastal counties. The local economy as well as wildlife are suffering because of the event.
Florida’s Red Tide is a coastal event. HABs can also occur inland in freshwater. August 2, 2014, the city of Toledo, Ohio issued an advisory warning residents to not use water from the city’s water system (https://weather.com/news/news/toledo-ohio-water-algae-lake-erie-20140802) An algae toxin, microcystin, was found in the city’s water supply in concentration higher than the 1 part per billion that the State’s standards allowed. The microcystin came from a bloom of blue-green algae, or more correctly cyanobacteria, that occurred in the western end of Lake Erie, their source water. The event lasted three days. Imagine three days without tap water!.
Right here in Arkansas that same year swim beaches in Lake Nimrod were closed because of a HAB (https://katv.com/archive/lake-nimrod-closes-after-possibility-of-harmful-algae-discovered). That closure was also a result of Microcystin from a bloom of cyanobacteria. The closure lasted for several days.
Aquatic conditions that promote algae growth include sunlight, temperature, pH, as well as the presence of hydrogen, carbon, oxygen, nitrogen, phosphorus, sulfur, iron, and trace elements (https://www.e-education.psu.edu/egee439/node/694). Most HABs in freshwater systems are the result of cyanobacteria. Cyanobacteria tend to grow best when the temperature is above 25C (77F), with intermittent exposure to intense sunlight, in stable or sluggish water with low turbidity, and when the nutrients nitrogen and phosphorus are present (http://www.cees.iupui.edu/research/algal-toxicology/bloomfactors). Most of these conditions occur naturally and we cannot do much about them. But, increased nutrient loading into a body of water can exacerbate the situation. Extreme storm events may also wash nutrients into the water contributing to the problem, especially if the storm is followed by an extended drought. Stagnant water can then lead to retention of nutrients in the water (https://www.epa.gov/sites/production/files/documents/climatehabs.pdf). Well, that kind of sounds like late summer in Arkansas.
So, what can a person do to help manage HABs or to avoid the negative impacts. Here are a few suggestions:
• When a severe algae bloom is present in a stream or lake, avoid contact with the water,
• Keep pets and livestock away from water with severe algae blooms,
• Learn how to manage fertilizer (nitrogen and phosphorus) to keep it on the land and not washing off of your property,
• Support local watershed management and source water protection efforts.