Making real science accessible and interesting for all people.
Thursday, December 16, 2010
Finished grape juice vinegar experiment
It has been four weeks since I started my batch of grape juice vinegar. (Click here for original post) For some unknown reason this batch is a lot "cleaner" looking then the last batch of cider vinegar I made. Despite the differences in appearance it was still the same process that made this batch of sugary grape juice into a vinegar. This batch started with grape juice and sugar, then when through fermentation where yeasts and molds converted the sugar into ethyl alcohol. Once alcohol levels were high the yeasts and molds were killed off for the most part and Acetobacter sp. bacteria metabolized the alcohol into acetic acid making it vinegar.
This batch of vinegar tasted much better then my previous batch. I believe using the old vinegar as a starter and adding extra sugar was the key. It had an interesting complicated sort of flavor. A sort of sweet, fruity, musty, acidic flavor. It might not win any state fare prizes but I'm satisfied by the fact that it tasted at least somewhat good.
Weed corridors
Seeds move through the landscape in a variety of different ways, the most important are likely wind, water, and animal. When placing a garden, designing a landscape, or trying to manage or understand natural areas this is extremely important to factor in. Understanding how seeds move through the landscape can mean both good and bad things. For example, understanding how a stream floods can aid where willow or cottonwood seeds will be deposited for habitat restoration. Or if you place your garden in a low laying area or a place that catches wind deposited seeds you could have a huge weed problem. Unfortunately, we don't always have control of how we design our landscapes or where we place our gardens, we simply have to deal with the problems that come a long with the site. Also, it is often hard to determine seed corridors until it is too late.
For example, the college garden area below:
Note the large gap between the two walls. This appears to be a major source of weed seeds that are deposited in the garden. Seeds blow in through this gap and are deposited in the garden. The first beds immediately adjacent to this gap can have pretty bad weed problems compared to the rest of the garden area. One solution to this would be to close the gap, but that really isn't a possibility so I'll just have to deal with it. Another solution if we were in the design phase of this garden might be raised beds. Often, far fewer seeds will be deposited in beds slightly elevated above ground. However, in the case for these gardens we wanted sunken beds in order to conserve water, so we'll just have to deal with the weeds.
The dry wash below is another example of a weed corridor:
Any type of waterway, whether it is perrenially wet or dry for most of the year transports huge amounts of seeds. If you want to identify what invasive species will be invading an area in the near future you need to look along waterways. Water transports seeds and provides a moist habitat with higher quality soil in which all kinds of plants can get a foot hold in the landscape. This includes ditches a long roads. Before designing a landscape or placing a garden it is very important for you to know how water flows through the land and where it concentrates. This is much easier then identifying where wind deposits seeds. Simply observe water movements in the landscape during and after large rain events, then adjust your landscape design accordingly. Riparian areas, whether dry most of the year or wet, are also major corridors for the movement of animals which carry sometimes large amounts of seeds.
Tuesday, December 14, 2010
Sprouts
After being asked several times how to sprout seeds I though maybe I should try to figure this out. So I did a little research and found it is extremely easy. So I sprouted some of my own seeds (below) and found that in-fact, it was even easier then I initially though. I'm surprised more people don't do this. The basic process is first, soak seeds 8 to 12 hours. You will need some sort of jar to soak them in where the water can be easily drained off. I used a 1 quart mason canning jars with their bands. The bands were used to hold pantyhose in place.
Then, after soaking the water was drained off through the pantyhose and the jars were left to sit on their sides. The seeds are still wet at this point so they continue to sprout. the sprouting seeds need to be rinsed two or three times a day simply by filling the jar up with water (through the pantyhose) and then immediately draining the water off through the pantyhose. The moisture keeps the seed sprouts growing and rinses a lot of the bacteria. If you set your sprouts in sunlight they will green up. Keep doing this until your sprouts are the size you want to eat them. I started eating my sprouts on day three but continued to rinse them and let them grow until day six. Personally, I thought they tasted better the longer they grew and the greener they got.
sproutpeople.org/.
Sprouting is a great way to improve the nutritional content of seeds. Apparently, all seeds contain anti-nutritional factors called phytic acids. With only a few hours of soaking these anti-nutrients disappear and the seed begins to increase in protein, vitamin, and fiber quantity and quality. The nutrients continue to increase with several days of sprouting.
Then, after soaking the water was drained off through the pantyhose and the jars were left to sit on their sides. The seeds are still wet at this point so they continue to sprout. the sprouting seeds need to be rinsed two or three times a day simply by filling the jar up with water (through the pantyhose) and then immediately draining the water off through the pantyhose. The moisture keeps the seed sprouts growing and rinses a lot of the bacteria. If you set your sprouts in sunlight they will green up. Keep doing this until your sprouts are the size you want to eat them. I started eating my sprouts on day three but continued to rinse them and let them grow until day six. Personally, I thought they tasted better the longer they grew and the greener they got.
Day two. These sprouting seeds have a small root showing after being drained from the initial soaking about 12 hours ago. I left my jars like this in a sunny window, rinsing three times a day. |
sproutpeople.org/.
Sprouting is a great way to improve the nutritional content of seeds. Apparently, all seeds contain anti-nutritional factors called phytic acids. With only a few hours of soaking these anti-nutrients disappear and the seed begins to increase in protein, vitamin, and fiber quantity and quality. The nutrients continue to increase with several days of sprouting.
Check out Wikipedia for more information on this: en.wikipedia.org/wiki/Sprouting
Wednesday, December 8, 2010
Garden economics update
Last months garden on November 8th. |
December 8th garden |
Weather conditions have been near perfect the past few weeks with highs in the 70's and lows in the 40's most of the time. We did have a night or two with frost but they were so lite frost sensitive plants easily recovered. This winter will probably be a dry one being we missed the late November rains we often get and I suspect we will have some more freezing temperatures due to this lack of rain. Problem with pests is also minimal due to the cooler temperatures. We probably won't see a return of many pests until March or so. But that said, everything is growing extremely well.
So here is a garden update for the month of November:
Home College
Hours of work: 2.25 1.25
Calories burned: 715 397
Food produced: .75 lbs. 1 lbs.
Calories produced: 113 85
Production: $11.34 $4.48
Total Cost: $0 $0
Net:
Summary of garden project:
Home Garden
Hours of work: 7.5 5.75
Calories burned: 2049 1540
Food produced: 0.75 lbs. 1 lbs.
Calories produced: 113 85
Production: +$11.34 +$4.48
Total Cost: -$61 -$61
Net: -$49.66 -$56.52
So nothing impressive at this point. At this point I'm a little concerned about even breaking even, but we'll see. Over the next month or so things should really pick up though. A lot more chard, lettuce, and chives should be produced along with some snow peas, carrots, radishes, and turnips. I'll post an update for the garden in about a month.
Mixed romaine lettuce |
Wednesday, December 1, 2010
Sauerkraut final product
This is what our cabbage looked like to start after being shredded up, mixed with sea salt, and weighed down. This apparatus was then left to sit at room temperature for about a month. |
And this is what our final product of sauerkraut looks like after sitting at room temperature for one month. |
So the sauerkraut we started a month ago is finally finished. To review, I simply 1. shredded the cabbage, 2. mixed the shredded cabbage with sea salt to taste in a container with vertical or strait sides, 3. weighed down the cabbage so it was submerged under the liquid, and 4. waited several weeks for lactic acid fermentation to take place. The biological processes that took place to make this sauerkraut are fairly interesting. First, salt removed water from the cabbage through osmosis to form the liquid the fermentation would take place in. Salt also works as a preservative by excluding harmful bacteria by killing them off in a few days time. Leuconostic sp. and Lactobacillus sp. bacteria tolerate salty conditions and and acidify the salty cabbage juice by producing lactic acid. The increasingly acidic conditions also kill off harmful bacteria and encourage Leuconostic sp. and Lactobacillus sp. bacteria. The cabbage is also submerged under the cabbage juice to promote anerobic conditions (conditions without oxygen) which also kills off harmful bacteria and again encourages lactic acid production by Leuconostic and Lactobacillus. The remaining species of bacteria, especially Lactobacillus, at the completion of the sauerkraut are well known probiotics, which are bacteria that aid digestive health.
Here is a good website with additional information: www.wildfermentation.com/
Monday, November 29, 2010
Chili paste ferment
A glass container with fermenting chili puree mixed with water, sea salt and a small amount of sauerkraut juice held under the liquid surface by a water filled flask. |
A few weeks ago I harvested several pounds of various chili peppers from one of our college gardens. There was a variety of tobasco, jalapeneo, and who knows what else (I forgot what they were a long time ago). This was far more chili's than anyone of us wanted to consume. So the stems were removed and the chili's were pureed with some water until I had a fine chili paste. Sea salt was then added to taste. Several ounces of sauerkraut liquid was added in an attempt to speed the fermentation process. Nothing was exact, I just made sure there was enough water to submerge the paste under the flask. The submerged paste was then left at room temperature to ferment for several weeks. Currently, it is still fermenting and hopefully next week sometime I will taste it.
I became interested in fermenting chili's a few years ago when I started growing bumper crops in both the spring and fall. Being we can grow chili plants year round in Phoenix I have several plants that are many years old. A few of these plants have developed into bushes, one of which gets to six feet tall before I have to trim it. That said, I produce pounds and pounds of chili's annually and need something to do with them. I've never actually fermented them before so this is my first attempt and it seems to be going quite well. The process of fermenting chili's should be the same process as making sauerkraut. Salt and anerobic conditions prevent harmful bacteria from growing and encourage healthy fermenting lactic acid bacteria (probiotics). This then preserves the food, preventing spoilage. The only difference between the chili ferment and the sauerkraut is that the fermentation process appears to be much slower for the chili's. It is possible that the capsaicin slows or prevents some bacterial growth. Capsaicin is the substance found in chili's that makes them spicy.
Tobasco chili sauce is fermented in a similar way for three years in oak barrels. See here how Tobasco produces its famous chili sauce: www.tabasco.com/tabasco_history/hot_pepper.cfm. While I don't expect to have results comparable to the Tobasco brand name, hopefully something good will be produced.
Tuesday, November 23, 2010
Growing ginger in a microhabitat
Ginger plant hidden away in a safe greenhouse microclimate where it can grow protected from intense sun, heat, and cold. |
I'll admit, I'm pretty obsessed with figuring out how to grow things. There is so much that can be learned through simply trying to grow new plants. Even if its not something particularly or immediately practical, figuring out how to grow it can teach you about how to grow other more practical things. Ginger is an excellent example of this. Ginger: not practical where it is cold, or where it is hot, or where the sun is intense. Being we are in Phoenix Arizona, the sun is too intense and hot during the summer and too cold during the winter. One of my coworkers tried growing ginger plants from store bought roots (or stolons) several times before he finally figured out how to protect the plant. It turned out to require moist rich soil, and a shaded, cooler, and wetter portion of the greenhouse. Even here though the plant dies back during the hot part of the summer and cold part of the winter but comes back each fall and spring for several months. The goal is to eventually get it to flower, which may require a slightly different set of conditions.
The problem and reason why most people have "brown thumbs" is that they try once, it doesn't work, so they give-up. I have seen people grow things very productively in circumstances where they in no way should grow. The rule is, as with most everything, if at first you fail try again. The key is in growing the ginger... Microhabitat! A microhabitat is a small area in the landscape where conditions are slightly different from the rest of the habitat. For us to grow ginger successfully we had to find the microhabitat of temperature and light intensity different from the surroundings. The same goes for growing just about anything else, you must create or find the ideal light intensity, soil, and temperature for that plant to grow in. The same exact principle holds true in the environment. Why do most all plants grow in the desert? Microhabitat! Without plants like Palo Verde creating a shaded, cooler, moister, and better soil environment under their canopy very few desert plants would grow at all.
While growing ginger is an interesting lesson in microhabitat, ginger itself is a pretty interesting plant. Supposedly it has been found to have anti-viral, anti-bacterail, and anti-cancer compounds in it. If you want to read more about ginger click here: en.wikipedia.org/wiki/Ginger.
If you want to figure out how to grow your own ginger, purchase a ginger root from the local grocery store and plant in potting soil. The ginger root itself is actually a stolon, a sort of underground stem that also functions as a root and stores nutrients for the plant. The stolon will require moist but well drained soil and sunlight. While I don't know exactly, ginger doesn't seem to like temperatures above 100 degrees or below 40 degrees, and prefers humidity and partial shade. You will have to play around with the conditions to create the "perfect" microhabitat.
Cider vinegar final product
So the finished product of our cider vinegar experiment is finally complete after a month of waiting. As you can see from the above picture the finished product is quite gross and you probably wouldn't want to drink it straight. All those microorganisms, though not dangerous in themselves, might not be good for your stomach!
To start this project, all I did was place apple juice in a one gallon jar, cover the opening with panty-hose, and let it sit at room temperature for four weeks.
So during the past four weeks this is what happened: Atmospheric yeasts and molds fall into the apple juice and ferment sugars into alcohol (ethanol). This process of making alcohol is anerobic, meaning without oxygen, and is called fermentation. Once the yeasts and molds converted all of the sugar to alcohol, Acetobacter sp. of bacteria metabolized the alcohol into acetic acid (vinegar) aerobically (with oxygen).
1. Sugar + yeast -->Ethanol
2. Alcohol + Acetobacter sp. --> Acetic acid
If this process is allowed to continue the Acetobacter sp will begin to convert the acetic acid into water. If the process of making vinegar is carried out perfectly, the percent alcohol in the juice will produce the same percent of vinegar. So if 10% alcohol is produced this should make a 10% vinegar.
As you can see from the above picture, the vinegar is loaded with all kinds of gunk, which are bacteria, yeasts, and molds. In order to clean up the vinegar I filtered it though a coffee filter to remove the large chunks as much as possible. Then the filtered solution was pasturized by heating to about 180 degrees to kill the remaining microorganisms.
After this entire process I finally tasted the vinegar. Unfortunately it was quite watery which means I let it set out for too long. The alcohol content probably never got too high because I didn't add any sugar which also led to a low vinegar content. So I am trying vinegar making again. For this next batch I used 1/2 gallon of gape juice, 1 cup of sugar, and mixed it with the slurry left over from the first batch of vinegar. This time I am only going to let it sit for about two weeks or so to see what happens. If this batch doesn't work well, I'll just try again. Trial and error is a rule for science as well as success in life...
My next try at making vinegar. 1/2 a gallon of grape juice, 1 cup of sugar, mixed with about 1 cup of slurry from the last batch of vinegar I made. |
Thursday, November 18, 2010
Growing a coconut tree
Coconut seed planted sideways and half buried in potting soil. |
For more information on the coconut check out Wikipedia: en.wikipedia.org/wiki/Coconut
We planted the above coconut seed about a month ago and a root nub appeared after a few weeks. The nub hasn't grown much since that time but time will tell if its alive or not. From what I've read coconuts grow well in hot humid environments that have no freezing temperatures ever, such as the tropics. Unfortunately for us in Phoenix we get frosts about every three years, so our tree will have to remain in the greenhouse. But at this point we don't even know if we can get the seed to sprout into a tree. We'll report back if and when it actually works.
The three "eyes" on the bottom of the coconut. |
Growing pineapples
To the right are three pineapple plants we started about a year ago in our greenhouse. Anyone can start their own pineapple plant in a warm sunny window, a one gallon pot or larger, some potting soil, and a store bought pineapple. Simply cut off the pineapple top so you have about 1 inch of the pineapple attached to the leaves and let is dry for several days. Then bury the 1 inch remaining portion of the pineapple in the potting soil and water. Make sure the soil stays wet and the pineapple will eventually start to root in a week or two. Not all tops will root and you may have to try this with a few different pineapple tops before it will work. You can pull up your pineapple in the first few weeks to see if any roots are growing, but be gentile as to not break any roots. You will know your pineapple rooting experiment is working if the very central leaf in the top is growing. The top center leaf is the leaf growing from the plants apical meristem, which is growing tissue at the apex or top of the plant. All plants have an apical meristem which adds height or length to the plant. If the apical meristem is growing your plant is healthy. We are going to keep our pineapples growing indefinitely. We have heard that it is possible to produce fruit after about three years, but we'll see.
Growing plants of all types is an important and easy learning/teaching tool, or skill for that matter. All kinds of things can be learned about plants as you grow them, everything from botany to agriculture to history and culture. Growing a pineapple in this way teaches plant propagation as well as about apical meristem growth. Another interesting thing about pineapple fruit is that they contain an abundance of protease, an enzyme that digests protein. Which makes me think... maybe there is some cool protein digestion experiment we can think up of using pineapple.
For more information on the pineapple check out wikipedia: en.wikipedia.org/wiki/Pineapple
Growing plants of all types is an important and easy learning/teaching tool, or skill for that matter. All kinds of things can be learned about plants as you grow them, everything from botany to agriculture to history and culture. Growing a pineapple in this way teaches plant propagation as well as about apical meristem growth. Another interesting thing about pineapple fruit is that they contain an abundance of protease, an enzyme that digests protein. Which makes me think... maybe there is some cool protein digestion experiment we can think up of using pineapple.
For more information on the pineapple check out wikipedia: en.wikipedia.org/wiki/Pineapple
Tuesday, November 16, 2010
Vertical potatoes in a barrel
While I generally do not like growing potatoes in the garden because they take up a lot of space and are a low value crop, I will be trying to grow them vertically this winter in an old barrel. By growing potatoes vertically in the barrel, hopefully we can produce a barrel full of potatoes. Potatoes are remarkably easy to grow and a simple web search yields numerous ways to grow them such as in old tires, bags, straw, cages, and others. We have an old half of a plastic 55 gallon drum on hand which I have tried to grow potatoes in before but have failed. Last winter the potato barrel failed I believe because of too little and bad soil. So this winter I am trying again. To begin, a plastic 55 gallon barrel half with many 1/2 inch holes drilled into the bottom for drainage was filled with 12 inches of a well draining soil mix. The barrel was elevated off of the ground to improve light exposure and drainage (The barrel was elevated above the shadow of a wall). 12 potato "eyes" were then planted in the soil and watered. 12 eyes is way to many but I over did it in case some don't come up or don't grow as vigorously, the extras will be thinned out later. To obtain sprouting eyes you can simply cut a chunk of potato out from around an eye from a store bought potato. Once the chunk is cut out let it dry for about a day. A lot of gardening resources advise against this due to transfer of diseases but I never had a problem (yet!). Unfortunately, for us in Phoenix our potato growing season begins in the fall and ends in May or June and seed companies usually don't sell certified disease free seed potatoes until March. So this is currently the only way I know of planting potatoes for the Phoenix growing season.
Once the potatoes sprout and are about four to six inches tall the plants will be bury with four inches of soil. This will be repeated until the barrel is full of soil. Potatoes are supposed to grow in each layer of soil, thus filling the barrel. Then the potatoes will be left to grow in the barrel until May or June. Hopefully I can get it to work this winter but we'll see. I already think there may be a problem with the barrel shading much of the soil due to the low angle of the the winter sun. Hopefully, the potatoes will still grow partially shaded. Once the potato plants reach the top of the barrel and it is full of soil, shading will no longer be an issue.
Some of the potato eyes I used to start my potato barrel. There are red, russet, and purple potatoes for starting. They were cut from store bought potatoes and dried for one day before planting. |
Once the potatoes sprout and are about four to six inches tall the plants will be bury with four inches of soil. This will be repeated until the barrel is full of soil. Potatoes are supposed to grow in each layer of soil, thus filling the barrel. Then the potatoes will be left to grow in the barrel until May or June. Hopefully I can get it to work this winter but we'll see. I already think there may be a problem with the barrel shading much of the soil due to the low angle of the the winter sun. Hopefully, the potatoes will still grow partially shaded. Once the potato plants reach the top of the barrel and it is full of soil, shading will no longer be an issue.
Monday, November 8, 2010
November Garden update
The gardens have been in for slightly over a month now. All (or nearly) of the hard work of tilling and planting is done and seeds are sprouting. Hopefully in a month or so we will begin to harvest some of our first produce. Now that we are well into November, hot 90 degree plus weather is (hopefully!) behind us so watering and seedling monitoring can be minimized. We did have some problems with predation and a heatwave killing some of our seedlings but now with the cooler weather and the plants established that is (hopefully) behind us.
What we planted: Leeks, green onions, Tohano Odom Multiplier Onions, Snow Peas, Sweet Peas, Carnival Carrots, Dragon Carrots, Easter Egg Radishes, Plum Purple Radishes, Cabbage, Broccoli, Cauliflower, Ruby-red Swiss Chard, Chichiquelite Greens, Black-seed Simpson Lettuce, Freckles Romaine Lettuce, Australian Yellow-leaf Lettuce, Early Wonder Beets, mixed Romaine Lettuce, and several types of Garlic including Sonoran, Chilean Silver, French Mild, Asian Tempest, Californina Early, and Shilla. All are heirloom seeds with the exception of the Cabbage and maybe the Green Onions and the Simpson Lettuce.
Here are the stats for this garden "economics" project for both my home and work garden.
Home College
Hours of work: 5.25 4.5
Calories burned: 1334 1143
Food produced: 0 lbs. 0 lbs.
Calories produced: 0 0
Seed cost: $35 $35
Soil amendments: $10 $10
Nu-ban FG: $16 $16
Total Cost: $61 $61
Calories burned was estimated using caloriesperhour.com. Hopefully we will catch up on calories once we start producing vegetables but since we are not growing high caloric value crops like potatoes or wheat we may not. Also not included in this is the cost of equipment since we already had all the tools on hand. I could estimate that a shovel, hoe, rake, hoses, and hand trowels cost about $60 but we have been using them for many years now. Cost of seeds is way over estimated because of seed saving and exchanging we have done with other gardeners. Seeds actually cost us only $35 but we will assume I bought all of my seeds. The reason my home garden required more time is simply because I have to hand water everything and the school garden has an automatic watering system (also not included in cost). So in all, I have eliminated start-up costs from this budget and have tried to include only what a typical gardener would have to purchase. If I were to try a little harder I could eliminate even more of the seed costs by seed saving, making more compost of my own, or finding a cheaper pest control alternative to Nu-Ban FG. Theoretically I could see costs getting close to $0 with some work.
I will have another update in December sometime. The majority of the time, money, and effort has already been put in so hopefully in December we will see some produce to pay back these costs.
What we planted: Leeks, green onions, Tohano Odom Multiplier Onions, Snow Peas, Sweet Peas, Carnival Carrots, Dragon Carrots, Easter Egg Radishes, Plum Purple Radishes, Cabbage, Broccoli, Cauliflower, Ruby-red Swiss Chard, Chichiquelite Greens, Black-seed Simpson Lettuce, Freckles Romaine Lettuce, Australian Yellow-leaf Lettuce, Early Wonder Beets, mixed Romaine Lettuce, and several types of Garlic including Sonoran, Chilean Silver, French Mild, Asian Tempest, Californina Early, and Shilla. All are heirloom seeds with the exception of the Cabbage and maybe the Green Onions and the Simpson Lettuce.
Here are the stats for this garden "economics" project for both my home and work garden.
Home College
School garden with sprouting garlic in foreground. |
Calories burned: 1334 1143
Food produced: 0 lbs. 0 lbs.
Calories produced: 0 0
Seed cost: $35 $35
Soil amendments: $10 $10
Nu-ban FG: $16 $16
Total Cost: $61 $61
Calories burned was estimated using caloriesperhour.com. Hopefully we will catch up on calories once we start producing vegetables but since we are not growing high caloric value crops like potatoes or wheat we may not. Also not included in this is the cost of equipment since we already had all the tools on hand. I could estimate that a shovel, hoe, rake, hoses, and hand trowels cost about $60 but we have been using them for many years now. Cost of seeds is way over estimated because of seed saving and exchanging we have done with other gardeners. Seeds actually cost us only $35 but we will assume I bought all of my seeds. The reason my home garden required more time is simply because I have to hand water everything and the school garden has an automatic watering system (also not included in cost). So in all, I have eliminated start-up costs from this budget and have tried to include only what a typical gardener would have to purchase. If I were to try a little harder I could eliminate even more of the seed costs by seed saving, making more compost of my own, or finding a cheaper pest control alternative to Nu-Ban FG. Theoretically I could see costs getting close to $0 with some work.
I will have another update in December sometime. The majority of the time, money, and effort has already been put in so hopefully in December we will see some produce to pay back these costs.
Tuesday, November 2, 2010
Make Your Own Sauerkraut
Whether you know it or not, if you are of European or Asian decent, your very presence on this earth may be due, in part to... sauerkraut! Yes, it is a fact, sauerkraut is thousands of years old and has been (or one of its varieties) a European, Asian, and later even a North American staple for much of that time. Sauerkraut is in-fact German for "sour cabbage". Cultures stretching from Europe, through the Middle East, and all the way to Japan have all had their versions of fermented cabbage. Besides German sauerkraut, Korean fermented cabbage and vegetables are probably the most famous and are known as Kimchi. Some of the first records of fermented cabbage come from the ancient Greeks, Romans, and slaves building the Great Wall of China. So yes, depending on your decent, your ancestors probably ate some form of fermented cabbage and owed their well being to it. Unfortunately, sauerkraut has fell out of favor in recent decades in much of the Western world, but for no particularly good reason. So today we are going to discuss how you can make your own sauerkraut, a fascinating biological process that is far cheaper, better tasting, and healthier then any kraut you can buy at the store.
The process is very easy and only requires sea salt and cabbage. You must use sea salt or canning salt, otherwise your cabbage will not ferment. Simply shred your cabbage and them mix with the sea salt in a glass or stoneware container. Avoid plastic or metal containers as they can degrade in the fermentation process. Cabbage and other vegetables are traditionally done in a stoneware crock. I typically use gallon pickle jars or two liter beakers. The key is finding a container that you can place a weight in to keep the cabbage submerged under the liquid. Typically strait edged jars or crocks work best, jars with tops that curve inwards make the cabbage difficult to weigh down. When I mix the cabbage with the salt I usually add a handful of cabbage and then sprinkle it with salt (not too much!), then mix by hand (clean hands!) and repeat until I have filled my container or have no more cabbage left. The amount of salt to add is not an exact science, you can add to taste and usually less is better. You will need just enough salt though to remove enough liquid from the cabbage so it can be submerged. Also, make sure to mix very well so the salt is evenly distributed in the cabbage. Once you have finished mixing you must weigh down you cabbage, which will also help in extracting moisture, and then let it sit. Your weights can be any clean thing that you can find. People use rocks, glassware such as cups filled with water, wood, and even plastic bags filled with water. Check on the ferment everyday or so and press down on the weight, this ensures the cabbage remains submerged and releases carbon dioxide that forms as a result of fermentation. After a week or slightly more, or after the bubbles stop, your sauerkraut is ready to eat.
The process of making sauerkraut is known as lactic acid fermentation. Similar to alcohol fermentation with an input of sugar but different in that the output is lactic acid as opposed to ethyl alcohol. Several species of bacteria are responsible for sauerkraut fermentation. These bacteria are controlled by sugars in the cabbage, salt content, anaerobic conditions (without oxygen) by submerging the cabbage, and pH (acidity). During the first several days of fermentation coliform species of bacteria quickly consume all of the oxygen in the liquid and ferment, producing lots of carbon dioxide bubbles and dropping the pH from about 6 to around 4.5. The salty, anaerobic, and acidic conditions (pH~4.5) kill off coliforms around day four and are Leuconostic sp. bacteria quickly populate the cabbage. Leuconostic bacteria then produce lactic acid, dropping the pH to about 4.2 which kills them off and allows Lactobacillus sp. bacteria to replace them. Lactobacillus sp. continues production of lactic acid, dropping the pH to about 3.9 or so where it will stay for up to several months. It takes slightly more than a week for this process to happen depending on temperature and salt content. The sauerkraut is safe to eat at this point and full of healthy probiotic organisms (Lactobacillus sp.). In a week or two I will report back on the results of this sauerkraut experiment.
My cabbage fermentation container. One head of shredded cabbage mixed with sea salt. This can be done in a much larger container like a crock with many heads of cabbage. Salt pulls the water out of the cabbage and a weight is placed on-top of the cabbage to keep it submerged. After a little over a week, or after it stops bubbling, the sauerkraut is ready to eat. |
The process is very easy and only requires sea salt and cabbage. You must use sea salt or canning salt, otherwise your cabbage will not ferment. Simply shred your cabbage and them mix with the sea salt in a glass or stoneware container. Avoid plastic or metal containers as they can degrade in the fermentation process. Cabbage and other vegetables are traditionally done in a stoneware crock. I typically use gallon pickle jars or two liter beakers. The key is finding a container that you can place a weight in to keep the cabbage submerged under the liquid. Typically strait edged jars or crocks work best, jars with tops that curve inwards make the cabbage difficult to weigh down. When I mix the cabbage with the salt I usually add a handful of cabbage and then sprinkle it with salt (not too much!), then mix by hand (clean hands!) and repeat until I have filled my container or have no more cabbage left. The amount of salt to add is not an exact science, you can add to taste and usually less is better. You will need just enough salt though to remove enough liquid from the cabbage so it can be submerged. Also, make sure to mix very well so the salt is evenly distributed in the cabbage. Once you have finished mixing you must weigh down you cabbage, which will also help in extracting moisture, and then let it sit. Your weights can be any clean thing that you can find. People use rocks, glassware such as cups filled with water, wood, and even plastic bags filled with water. Check on the ferment everyday or so and press down on the weight, this ensures the cabbage remains submerged and releases carbon dioxide that forms as a result of fermentation. After a week or slightly more, or after the bubbles stop, your sauerkraut is ready to eat.
The process of making sauerkraut is known as lactic acid fermentation. Similar to alcohol fermentation with an input of sugar but different in that the output is lactic acid as opposed to ethyl alcohol. Several species of bacteria are responsible for sauerkraut fermentation. These bacteria are controlled by sugars in the cabbage, salt content, anaerobic conditions (without oxygen) by submerging the cabbage, and pH (acidity). During the first several days of fermentation coliform species of bacteria quickly consume all of the oxygen in the liquid and ferment, producing lots of carbon dioxide bubbles and dropping the pH from about 6 to around 4.5. The salty, anaerobic, and acidic conditions (pH~4.5) kill off coliforms around day four and are Leuconostic sp. bacteria quickly populate the cabbage. Leuconostic bacteria then produce lactic acid, dropping the pH to about 4.2 which kills them off and allows Lactobacillus sp. bacteria to replace them. Lactobacillus sp. continues production of lactic acid, dropping the pH to about 3.9 or so where it will stay for up to several months. It takes slightly more than a week for this process to happen depending on temperature and salt content. The sauerkraut is safe to eat at this point and full of healthy probiotic organisms (Lactobacillus sp.). In a week or two I will report back on the results of this sauerkraut experiment.
Monday, November 1, 2010
Growin' 'shrooms
Growing mushrooms is something I have been interested in doing for a long time. It is also kind of something I have been scared of, fearing I might grow some sort of poisonous mushroom by accident. Finally, after reading up on mushroom growing I overcame my probably unfounded fear and purchased Espresso Oyster mushroom spawn from Fungi Perfecti for $26. Mushroom spawn is simply a mass of mushroom mycelium growing in some type of medium. Mycelium is a mass of fungal hyphae which are similar to plant roots but for fungi. Mold is the most common way of referring to mycelium or hyphae.
Fungi, though often associated with plants are in-fact not plants at all. I suppose they are somewhere between a plant and an animal. Plants use sunlight to photosynthesize water and carbon dioxide into sugar for energy to live. Animals must consume food for energy, which is similar to mushrooms. As we know however, animals eat food and digest it internally in our stomachs. Fungi are weird in that they actually digest their food outside of their body first and then consume it. This is exactly what mushroom (fungi) mycelium is doing in dirt, on your bread, in wood, or as in the spawn above.
Supposedly, growing mushrooms is pretty easy. They don't need a lot of light, they just need some sort of growth medium or "food", and some water in a semi-sterile environment. So I chose two growth mediums or "foods" for my spawn, used coffee grounds and toilet paper. According to what I read both are excellent growth mediums for oyster mushrooms. Both mediums need to be sterilized and fortunately used coffee grounds are sterilized in the process of making coffee. Toilet paper on the other had needs to be sterilzed with boiling water. I simply boiled tap water and poured it on top of the role of toilet paper to sterilize it, amazingly it absorbed about half a gallon of water. Once the paper cooled I removed the cardboard cylinder from the middle and filled the hole with spawn. Then the toilet paper role and spawn were closed up in a gallon sized plastic bag with the bag left slightly open to allow for breathing.
As for the used coffee grounds, eight holes were drilled into the bottom of a five gallon bucket and about three gallons of coffee grounds were mixed with about 3/4ths gallon of spawn. The spawn and coffee grounds were already pretty wet so no water was added. Eight holes were also drilled around the surface of the mixture to help drain off carbon dioxide. Lastly, a plastic bag with holes in it was used to cover the bucket to help hold in moisture and prevent contamination.
From what I read mushrooms should be growing in about three weeks from both of these mediums. Hopefully that is the case but you never know. I have botched up my fare share of experiments in my life. Botching is a normal part of the scientific discovery. If it is botched up hopefully I'll discover something awesome. I'll report back on the results in several weeks.
A mass of oyster mushroom spawn growing on sawdust. |
Supposedly, growing mushrooms is pretty easy. They don't need a lot of light, they just need some sort of growth medium or "food", and some water in a semi-sterile environment. So I chose two growth mediums or "foods" for my spawn, used coffee grounds and toilet paper. According to what I read both are excellent growth mediums for oyster mushrooms. Both mediums need to be sterilized and fortunately used coffee grounds are sterilized in the process of making coffee. Toilet paper on the other had needs to be sterilzed with boiling water. I simply boiled tap water and poured it on top of the role of toilet paper to sterilize it, amazingly it absorbed about half a gallon of water. Once the paper cooled I removed the cardboard cylinder from the middle and filled the hole with spawn. Then the toilet paper role and spawn were closed up in a gallon sized plastic bag with the bag left slightly open to allow for breathing.
My sterilized toilet paper roll with spawn filling the middle hole. The brown specks are pieces of saw dust. The core of sawdust spawn appears white in this picture because it has been covered with white mycelium. Normally this gallon size plastic bag would be nearly closed to prevent contamination and to hold in moisture. |
As for the used coffee grounds, eight holes were drilled into the bottom of a five gallon bucket and about three gallons of coffee grounds were mixed with about 3/4ths gallon of spawn. The spawn and coffee grounds were already pretty wet so no water was added. Eight holes were also drilled around the surface of the mixture to help drain off carbon dioxide. Lastly, a plastic bag with holes in it was used to cover the bucket to help hold in moisture and prevent contamination.
Mixture of about three gallons of used coffee grounds and 3/4ths gallon of sawdust spawn. Holes in bucket around surface of mixture were drilled right after this picture was taken. Bucket was then covered with a plastic bag with holes to hold in moisture and prevent contamination. |
Wednesday, October 27, 2010
DIY (mostly) organic pest control
Effective organic, or mostly organic, pest control can be a very difficult process. However, with careful "scientific" observation and research anyone should be able to effectively control pests in the garden and around the house with mostly organic methods. While traditional chemical pesticides are extremely effective they can be a little too effective when they kill beneficial insects. Chemical pesticides definitely have strong negative health side-effects that if we knew the truth about we probably wouldn't be messing around with as much. I became a lot more serious about going organic when I learned that scientists often inject mice with pesticides in order to induce cancer or severe allergies (They are injected with higher concentrations than we deal with but it still makes me want to avoid them). Not that chemical pesticides don't have a place in pest management, I just like to avoid them as much as possible.
So how does a regular person begin doing their own organic pest control? First you must identify what insects you are dealing with. In my garden at home I identified three problem insects: cockroaches, crickets, and green caterpillars. At my work garden I identified cockroaches and crickets. I observed these insects eating my produce both during the day while tending my garden but also by going out and seeing what was happening at night with a flashlight. Going out at night was extremely beneficial in that I found almost "Egyptian plague" numbers of crickets around my house.
Three of my preferred semi-organic pest controls. NiBan-FG uses Orthoboric acid to kill insects when they eat the bait, diatomaceous earth kills insects as they crawl across it, and Semaspore bait infects crickets and grasshoppers that eat it with a parasitic microbe. Be sure to wear a face mask when applying diatomaceous earth and to use 'food grade". Pool filter diatomaceous earth is significantly more dangerous to breath in and should be avoided. These products, and Bacillus thurgingiensis, can be found online just by typing their name into a search engine. |
Second, after identifying the pests I researched online effective organic treatments for these pests. There are a whole host of organic pest controls and I began testing some. With each one I used careful observations were made of what effects they had and if they were effective or not. For example, with chemical pesticides I found slightly decreased growth of my plants but all the insects, including beneficial ones, were dead. Even the lizards were killed by the pesticides. Garlic and chili pepper deterrents were also tested. Both slightly reduced pest problems but not enough. They were very effective against deterring rabbits though. Then soap sprays on the plants were tested, also not very effective. After working though this process of testing and observing I finally came across three products that were effective for my gardens. Bacillus thuringiensis bacteria killed catapillars effectively, Semaspore greatly reduced crickets, and NiBan-FG killed the roaches and crickets. Food grade diatomaceous earth was also found effective at killing all kinds of bugs when placed
A "pet" lacewings. |
Finding this combination took me several years and a lot of trial and error but it has been worth it. Patience and a willingness to try new things is the key. I am still looking for more effective treatments through careful observation or information I come across. Also, this pest control costs about $30 per year compared to the hundreds people often spend on chemical pesticides annually.
DIY mostly organic pest control
1. Identify the pests.
2. Research and locate items that control these specific pests.
3. Apply pest control and observe results.
4. Repeat until you come up with a satisfactory solution for your home/garden.
5. Keep observing and be willing to try new things.
The key is careful observation, researching new solutions, and PATIENCE! Trial and error is the name of the game, you must be willing to accept error! Each region/area/person has a different set of problems and therefore a different set of solutions. Any solutions you find specific to your situation can be of great help to others.
Wednesday, October 20, 2010
Foraging the city: Olives
Olives will be ripening now through December in the Sonoran Desert. So yesterday I took a trip to Encanto Park in downtown Phoenix to see if I could find any olives ready for harvesting. At the park I found several olive trees ready for harvest. Olives develop on the tree green and as they ripen their color changes to a reddish-purple color and then finally to black. They are best to harvest just before they turn black. Olives grow amazingly well in the desert and are a huge food crop that largely goes unnoticed by the general desert dwelling public. Very few people actually do anything but be annoyed by and try to get rid of this abundant food source in Phoenix. So, being that olives are one mans trash, I hope to make that mans trash into a delicious olive treasure. So I picked three pounds of nice plump reddish-purple olives right off the tree. The problem and reason why olives are largely considered annoying trash is that if you were to bite into one right off the tree it would be disgusting. Unprocessed olives contain a bitter compound called oleuropein which makes them unpalatable. It is so disgusting that if you taste an unprocessed olive once you will never do it again. (Yes, I speak from experience.)
In order to make a disgusting olive into a tasty one we must fist brine and ferment it for at least a month. Both interesting biological processes in themselves. First the olives were rinsed off and a small cut made on one side of them. The cut allows for the brine to access the inside of the olive easier and can speed up processing by a few months. Once all the olives were cleaned and cut, they were placed in a one gallon jar and submerged in an 8% sea salt solution to brine and ferment them. A weight must be placed on top of the olives so they will not float to the top (We used a one-gallon ziplock bag filled with water to weigh the olives down). The salt solution will flush the oleuropein out the olives, kill bad bacteria, and allow for lactic acid fermentation to take place. Lactobacillus sp. bacteria carry out this fermentation and process some of the oleuropein into more tasteful substances. Once a week for three to four weeks the salt brine must be replaced with fresh brine. At week three taste an olive, if it don't taste good to you brine it for another week. At week three or four, or when the olives taste good, drain the olives of the brine and replace it with a flavored vinegar brine. We will discuss this process and the final vinegar brine more when this batch of olives is done in about a month.
One of the olive trees I collected three pounds of olives from in Encanto Park.
In order to make a disgusting olive into a tasty one we must fist brine and ferment it for at least a month. Both interesting biological processes in themselves. First the olives were rinsed off and a small cut made on one side of them. The cut allows for the brine to access the inside of the olive easier and can speed up processing by a few months. Once all the olives were cleaned and cut, they were placed in a one gallon jar and submerged in an 8% sea salt solution to brine and ferment them. A weight must be placed on top of the olives so they will not float to the top (We used a one-gallon ziplock bag filled with water to weigh the olives down). The salt solution will flush the oleuropein out the olives, kill bad bacteria, and allow for lactic acid fermentation to take place. Lactobacillus sp. bacteria carry out this fermentation and process some of the oleuropein into more tasteful substances. Once a week for three to four weeks the salt brine must be replaced with fresh brine. At week three taste an olive, if it don't taste good to you brine it for another week. At week three or four, or when the olives taste good, drain the olives of the brine and replace it with a flavored vinegar brine. We will discuss this process and the final vinegar brine more when this batch of olives is done in about a month.
My jar of brining and fermenting olives. Olives were cleaned, cut on one side, then submerged in an 8% sea salt solution. To keep the olives submerged they were weighed down with a water filled zip-lock bag. The opening to the container was covered with plastic wrap to prevent any contamination. |
Monday, October 18, 2010
Plant Breath: Transpiration
Amazingly enough, plants actually breath. They breath very different in comparison to us but yet they still breath. Plant 'breathing' takes place through tiny microscopic pores located on the surface of their leaves called stomata. Through these pores water and oxygen are released but carbon dioxide is absorbed. This process of breathing is called transpiration and actually pulls and moves water through a plant from the roots all the way to the leaves. We have developed a very simple way to measure plant transpiration using a tool called a potometer. Actually, I am sure someone else developed it before we did but we came up with it independently... but anyway.
At right you can see a picture of our potometer complete with a plant cutting. The device is made of a 1ml serological pipette and about 12 inches of small diameter rubber tubing. The smaller the graduated volume marks of the pipette the better. Ours is actually graduated with major marks at the 10ths (100 microliters) and minor marks at the 100ths (10 microliters). The pipettes and small diameter rubber tubing (we use 3mm inner diameter but larger can be used) can easily be found for purchase through an internet search and together should cost less than $10. You could also see if a local school lab would let you have or borrow these materials. Once you have your pipette and tubing simply join them together.
Next you will need the plant cutting that you are going to test on the potometer. Before you place the stem in the tubing you must first make a continuous column of water that goes all the way through the tubing and ends somewhere in the pipette. In order to do this you must submerge your tubing and part of your pipette under water. Make sure there are no air bubbles in the tubing and pipette. Then, by keeping the end of the tubing underwater insert the stem of your test plant into it. The stem cutting must be as fresh as possible! Make sure that only the stem portion of the plant cutting goes underwater. If the leaf portions of the cutting gets wet the plant will not transpire normally. When the plant stem is inserted into the tubing make sure it has a tight fit so nothing can escape or enter, and make sure there is no air bubble between the stem and the water. After all this is done you should have a column of water, with no air bubbles, that touches the stem and ends somewhere in the pipette. Tape this up somewhere like in the photo above and mark the starting point for the water in the pipette (the starting point will be where the water ends in the pipette).
After your potometer is set-up wait an hour or two and see how far down the water has moved the pipette to determine how much water has been transpired. The same volume of water that has been removed from the pipette has been absorbed and transpired out of the plant as it 'breathed'. This basic set-up can be used to make a variety of experiments such as comparing how much a plant transpired in the light vs. dark, different temperatures, comparing different species, and comparing different numbers of leaves. If you are doing a temperature of light comparison it is best to use the same plant species and maybe the same plant cutting. If you don't use the same cutting try to use the same number of leaves. Or if you are comparing different species try to make leaf area as equal as possible for each cutting as much as possible. A whole variety of tests can be used to demonstrate plant water use with this simple device.
At right you can see a picture of our potometer complete with a plant cutting. The device is made of a 1ml serological pipette and about 12 inches of small diameter rubber tubing. The smaller the graduated volume marks of the pipette the better. Ours is actually graduated with major marks at the 10ths (100 microliters) and minor marks at the 100ths (10 microliters). The pipettes and small diameter rubber tubing (we use 3mm inner diameter but larger can be used) can easily be found for purchase through an internet search and together should cost less than $10. You could also see if a local school lab would let you have or borrow these materials. Once you have your pipette and tubing simply join them together.
Next you will need the plant cutting that you are going to test on the potometer. Before you place the stem in the tubing you must first make a continuous column of water that goes all the way through the tubing and ends somewhere in the pipette. In order to do this you must submerge your tubing and part of your pipette under water. Make sure there are no air bubbles in the tubing and pipette. Then, by keeping the end of the tubing underwater insert the stem of your test plant into it. The stem cutting must be as fresh as possible! Make sure that only the stem portion of the plant cutting goes underwater. If the leaf portions of the cutting gets wet the plant will not transpire normally. When the plant stem is inserted into the tubing make sure it has a tight fit so nothing can escape or enter, and make sure there is no air bubble between the stem and the water. After all this is done you should have a column of water, with no air bubbles, that touches the stem and ends somewhere in the pipette. Tape this up somewhere like in the photo above and mark the starting point for the water in the pipette (the starting point will be where the water ends in the pipette).
After your potometer is set-up wait an hour or two and see how far down the water has moved the pipette to determine how much water has been transpired. The same volume of water that has been removed from the pipette has been absorbed and transpired out of the plant as it 'breathed'. This basic set-up can be used to make a variety of experiments such as comparing how much a plant transpired in the light vs. dark, different temperatures, comparing different species, and comparing different numbers of leaves. If you are doing a temperature of light comparison it is best to use the same plant species and maybe the same plant cutting. If you don't use the same cutting try to use the same number of leaves. Or if you are comparing different species try to make leaf area as equal as possible for each cutting as much as possible. A whole variety of tests can be used to demonstrate plant water use with this simple device.
Thursday, October 14, 2010
Gross and easy enzymes: Hydrogen Peroxide and Catalase
Enzyme experiments are often limited to molecular labs with expensive and sophisticated equipment. There are however several enzymes that can be isolated very easily with minimal equipment and materials. Catalase is one such enzyme that anyone can access for experimentation. The process for isolating catalase, though easy, is like so many other cool biological experiments: its kind of gross. But first, what exactly is an enzyme? An enzyme is a protein that carries out a chemical reaction that normally would not take place. Our bodies, along with all other organisms, are loaded with hundreds of different enzymes that control when, where, and what chemical reactions happen. Specific types of enzymes only carry out one type of chemical reaction but can carry out that reaction hundreds of times over. Enzymes are essentially what do the 'work' of breaking down or digesting things such as our food and then building food molecules into cells to form our bodies. The reaction that catalase carries out is converting the potentially harmful hydrogen peroxide molecule into harmless oxygen and water molecules. This is essentially what happens:
Catalase enzyme + hydrogen peroxide --> catalase enzyme + water + oxygen
After the catalase breaks down hydrogen peroxide into water and oxygen, catalase is then available to carry out the same reaction again.
Samples of heart, kidney, and liver blended organs for catalase experiment.
The sediments at the bottom are tiny chunks that settled out.
In order for us to isolate catalase we must first locate some fresh liver. We get all of our liver, or any other organ meats, from the local grocery store. We then take about five to ten grams of liver (slightly smaller than a ping pong-ball) and place it in a blender with 500 ml of distilled or unchlorinated water then blend until homogeneous. Once you have a homogeneous mixture of liver juice, or any other juice for that matter, place several drops in a test tube. Next, add several drops of hydrogen peroxide to your liver juice test tube. If catalase is present in your liver juice, and it should be, foaming should take place. The foam bubbles are full of oxygen that the catalase is producing by breaking down the hydrogen peroxide. So the more foam that is produced the more catalase is present. You can repeat this experiment with kidney juice, or any other type of meat.
In the picture at right I tested heart, kidney, and liver juice for catalase by mixing them with hydrogen peroxide. From left to right we see the results for heart (no foaming), kidney (foaming), and liver (slightly more foaming than kidney). Based on these results we know that heart tissues have no catalase, kidney has catalase, and liver has the most catalase. So why would heart have no catalase while kidney and liver have a lot of catalase? Well the liver and kidneys are filtering and cleaning organs so having catalase present in them would aid the cleaning of blood of harmful hydrogen peroxide molecules. Heart on the other hand is not a cleaning organ so no catalase is present. Other organs and tissues can also be tested in this way but the liver and kidney are the only ones we have found that contain catalase. We have also tested plants but have only found spinach to contain catalase for some strange reason. Why the heck would spinach have catalase? If anyone can figure that out be sure to let me know.
Enzymes being large complicated proteins are very sensitive to temperature and pH. You can do more experiments on catalase by heating or cooling the liver juice to see what effects temperature has on foaming. Try putting it on ice or boiling it. Also, try adding a little baking soda mixed with the juice to see how the enzyme works in a basic pH solution or vinegar for a acidic pH solution. Nearly everything you need to know about basic enzyme function can be accomplished through these simple experiments. There are a few other enzymes that are also easy to handle in a non-lab environment that I will try to post at future dates.
Enzymes being large complicated proteins are very sensitive to temperature and pH. You can do more experiments on catalase by heating or cooling the liver juice to see what effects temperature has on foaming. Try putting it on ice or boiling it. Also, try adding a little baking soda mixed with the juice to see how the enzyme works in a basic pH solution or vinegar for a acidic pH solution. Nearly everything you need to know about basic enzyme function can be accomplished through these simple experiments. There are a few other enzymes that are also easy to handle in a non-lab environment that I will try to post at future dates.
Tuesday, October 12, 2010
Basic aquatic biology
The next time you are at a lake or pond you can quickly assess the aquatic life by simply picking up submerged rocks from the bottom. Depending on the habitat, if you look closely there should be an abundance of life present on and around the rock you pick up. The slimy layer is not simply 'slime', but a cool and complex biofilm made of algae, diatoms, bacteria, protists, and the slimes they excrete. There will also likely be several types of aquatic insects present on the rocks (a magnifying glass may be helpful but not necessary). Caddisflies, mayflies, stoneflies, midges, damselflies, and dragonflies all have immature nymph or larval stages that develop for up to year more underwater. Some of these species, such as mayflies, may only live above water as flying adults for a few hours before death. Other larger and better known species such as fish and crayfish may also be present but are often harder to observe. Picking-up and examining rocks from a body of water is also a trick many fishermen, especially those fly fishing, use to determine what types of things the fish may be eating. Speaking from experience, knowing a little aquatic biology can make you a much better fisherman! Bugs, slime, and potentially better fishing skills? This is biology at its best!
A common Arizona crayfish caught from East Clear Creek.
I tried my hand at examining some of these bugs and slime on a recent trip to East Clear Creek in near the Arizona Mogollon Rim. To start, I picked up many rocks covered with a thick slimy brown-green biofilm. Gross to some but cool to the biologist! On all of these rocks I found a remarkably low number of mayfly nymphs. Why so few aquatic insects? On closer inspection of the stream bottom there were dozens of crayfish scurrying. In Arizona, crayfish are not native and are a nuisance invasive that consumes aquatic insects and plants. This is bad news for many insect, fish, and amphibian species as they themselves are consumed or their habitat or food source is consumed by the crayfish. Fortunately, catching crayfish along with examining rocks can be a fun activity that can be used to teach aquatic biology to anyone. In addition, though I have never done so, crayfish are trapped, eaten, and enjoyed by people throughout the world.
As with some of the best scientific experiments, there is little to no equipment necessary to examine the things living on or around submerged rocks. A magnifying glass may be nice for looking at insects though. A basic aquatic insect field guide is also great if you want to identify species. If you have a microscope available a sample of the biofilm can be scraped off and stored in a vile to examine later. But for the more exiting task of capturing crayfish you will need a trap or container of some type. The container we used on our recent trip was a gallon milk jug with the top quarter cut off and the handle intact. Holes were also cut in the bottom so water can easily move through the container.
In future posts I plan on giving details on how a more thorough investigation of aquatic habitats can be carried out. I also hope to in the future acquire a trap and maybe have a little crayfish boil of my own.
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