Fall Leaves in a Sonoran Desert Riparian Zone

A Sonoran Desert riparian area in fall along Cottonwood Creek.

The desert is most definitely not known for spectacular fall colors.  Fall colors do however, find their place along some of the wetter desert water courses.  If perennial water sources are available, even if it is hidden below ground a short distance, the roots of large deciduous trees will find there way to it.  Sycamores, cottonwoods, and willows are all relatively common along streams and washes with perennial sources of water.  Even Arizona walnut and ash trees can be found in some of the more stable riparian zones.  These trees do not display the brilliant hues of red and orange common to eastern forests but do show off bright yellows that are in stark contrast to the dried out browns and greens of the desert.    Desert fall leaves are quite a rarity and are quite unique.  Typically, perennial water sources are considered perched water tables.  A perched water table simply is water that accumulated above the surrounding water sources, most often a result of bedrock that prevents water from penetrating deeper into the soil and out of reach of plant roots.

A recent hike I took demonstrated this concept extremely well.  The hike was along Cottonwood Creek near Lake Pleasant north west of Phoenix.  The majority of this hike is along Cottonwood Creek, which really isn't much of a creek considering water only flows in this creek a few hours every year.  The rest of the year the wash remains mostly dry, except for a few locations.  Nearly all washes in the desert are called dry washes, and for good reason: they are completely bone dry the majority of the year.  A few washes, such as Cottonwood Creek are fortunate enough to have areas that always remain wet.  Cottonwood Creek owes this moisture to its underlying geology.  First off, the creek bed lays at the base of two small bajadas between two small mountain ranges.  One bajada lays to the north of the creek bed and one to the south.  These bajadas and bedrock of the mountains are relatively steep and provide ample runoff to Cottonwood creek so it will run during periods of heavy rainfall.  Moisture is quickly lost into the deep sediments of the bajada and placed out of reach of deciduous tree roots.  In areas where bedrock are shallow though, moisture cannot penetrate deeply and remains closer to the surface within reach of plant roots.  Bedrock can also push water flowing underground towards the surface.  At these locations large deciduous trees take advantage of the shallow moisture and can in a few places form small but beautiful wooded areas.

Wildlife may not be obvious in these small wooded areas, but if you look at the ground you are sure to see evidence of animals.  Javelina and mule deer heavily utilize these small areas and their hoof prints are normally abundant.  In some area, such as along Cottonwood Creek, wild donkey's are also abundant and heavily utilize these areas.  The abundance of shade, food, water, and cooler conditions during hot dry summers gives great value to these areas for every creature.

Ocean Acidification

Ocean acidification is becoming a serious issue today.  Within the next hundred years it will become extremely serious.  Since the industrial revolution the oceans have been absorbing huge amounts of carbon dioxide due to the burning of fossil fuels.  As the oceans absorb this carbon dioxide it is converted into carbonic acid.  Oceans have already dropped 0.1 in pH and are predicted to drop another 0.3 to 0.5 in pH within the next 100 years.  These drops in pH might not seem like much but in reality are over a 100 percent increase in acidity.  This increase will have extreme consequences for shell forming organisms.  As acidity increases, the calcium in shells increasingly dissolve.  This can kill the organism or cause it to work harder to develop its shell.  Corral reef also will have increasingly difficult times forming as acidity increases.  In-fact, many people predict all corral reefs will be gone by the year 2050, which means a mass extinction of organisms that are completely dependent on corrals.  As shell bearing organisms disappear, organisms higher up the food chain also will disappear along with there food sources.  No one really know what exactly is going to happen, but everyone agrees it will not be good.  Fortunately, the solution to this problem is within reach.  To prevent continued acidification we must stop the mass burning of fossil fuels and switch to sustainable energy sources such as wind and solar.  Only with this switch can we decrease the increase in carbon dioxide and therefore stop global warming as well as ocean acidification.  Below is a documentary that aired on Discovery Planet Green that does an excellent job covering this topic. 

Montezuma Castle National Monument: Montezuma's Well

Montezuma's Well, part of Montezuma Castle National Monument.  This is the well viewed from the cliffs surrounding the pond.

The Montazuma's Well portion of Montezuma Castle National Monument is the lesser known of the two sections of the park.  It has far fewer visitors every year, but I personally find this section far more interesting.  First of all, the "well" itself is pretty interesting.  This "well" is simply a hole in the ground pond, quite an unusual landscape feature and I know of nothing quite like it.  This pond is located on a hill top that caved in as water dissolved away the limestone bedrock forming the hill.  Nearly vertical cliffs line all sides of the pond and there are well over 100 stairs down into this hole along the trail.  Ancient Native American ruins are built into many of the cliff walls around the pond.  If you think about it, this would have been quite a nice place to live 1000 years ago or so.  At least compared to the surrounding desert.  The surrounding Upper Sonoran Desert is similar to what is found at the Montezuma Castle portion of the National Monument, however, it is slightly higher elevation.  This means it is slightly cooler and receives a little more rain, just enough to support Juniper trees in addition to all the other plants found in the desert we discussed in our previous post.  While Junipers do add another food source, a little more shade, and a source of materials, it still doesn't make living out in the open desert possible.  Within the "well" area, the pond moderates extreme temperatures, supports trees that provide shade, and provides water.  All this making for a nice place to live during ancient times.  Every time I have visited the well in the summer though, I still think it would be an unbearably hot place to live.   I have noticed the cliff walls where the ruins are located are considerably cooler though.  Hanging out in the cliff walls during the heat of the day was probably a major way ancient inhabitants avoided the heat. 

Montezuma's Well at the outlet, where the pond flows into one of the surrounding cliffs.

If you aren't at least sort of amazed just by the landscape structure of the well, than hopefully learning about the aquatic biology of the pond itself will amaze you.  The biology of the pond is truly weird, almost sci-fyish.  First of all, because the spring that feeds the pond come out of limestone there is a huge amount of carbon dioxide dissolved in the water.  This does not mean the water is poisonous, but does mean that fish cannot live in the pond.  Which would have been a bummer to me if I was an Native American living there 1000 years ago.  Algae, however, thrive on the abundance of carbon dioxide.  This algae supplies food to loads of amphipods, which are sort of like tiny freshwater shrimp.  At night time, huge numbers of non-blood sucking leaches migrate towards the surface to feed on the amphipods.  It is rather creepy imagining a mass migration of leaches swimming towards the surface. 

Vegetation along the canal the empties into Beaver Creek.

Once outside of the well, the trail also takes you down a cliff opposite the pond cliffs and along Beaver Creek.  This is actually my favorite section of the entire monument.  As mentioned before, water flowing out of the well flows into one of the cliffs surrounding the pond.  On the other side of the cliff, the water flows out of another cliff along the creek.  This water enters Beaver Creek in a truly beautiful desert oasis.  This area is very wet and shady.  Temperatures are far cooler here in the shade and thick vegetation.  Huge Sycamores and Ash trees fill the area.  The area has enough moisture to support beautiful Columbine flowers and even some poison ivy, so watch out.  This verdant green area is quite a refuge from the surrounding harsh desert landscape.  

The Science of Fishing

Bluegill.

Fishing may not seem like an extremely scientific activity, but in reality it can be extremely scientific.  When fishing you have to take into consideration the basic food chain, fish as well as bait behavior, and the local ecology.  For example, I grew up fly fishing for trout and learned a lot about all of the above.  Trout are towards the top of the food chain in a stream and mostly feed on small aquatic insects such as scuds, may flies, and caddis flies.   Every region and every stream has their own specific set of aquatic bugs.  So a basic knowledge of what types of bugs are in a certain stream will automatically give you a huge advantage towards a successful fishing trip.  You can easily identify the aquatic bugs of an area simply by picking-up rocks off the bottom of a lake or stream and seeing what bugs are crawling around on them.  Secondly, certain bugs are only active at certain times of the year and therefore fed on by fish at certain times of the year.  These bugs can be found simply by looking for what bugs are swimming around in the water or floating on top. 

A lot of fish behavior will be determined also by bug behavior as well as habitat.  I have found that in many trout streams bugs are most active during the middle part of the day and therefore trout are also most active during the middle of the day, making it the best time to fish.  Bass and bluegill though seem to be most active early in the morning or late in the evening, making those the best times to fish for these species.  As for habitat, nearly all fish like some sort of cover whether its a pile of rocks, weeds, or an over hanging bank making these the best areas to fish. 

Rainbow Trout.

But whatever you are fishing for, a little background knowledge can go a long ways.  Research and try to find out 1. what is available for the fish to eat at that time of the year (that is what lure or bait to use), 2. how is that food behaving or how can you get the fish to eat it (how to retrieve the bait or lure), 3. where should I place my lure or bait (in the current, next to the current, by a bank over hang, next to weeds...).  Looking at fishing this way make it a little more complex then just casting a worm out there and waiting.  But it can also make the whole experience a lot more educational, interesting and successful.  I definitely enjoy fishing a lot more when I look at the trip in this way.  With more fishing trips and more observations you should become more successful.  There is one additional guideline: whatever works for you use it, even if it breaks the above three guidelines.

Louisiana Wetlands and the Mississippi River Delta Part 2

A floating Louisiana marshland.  This wetland is characterized by thick mats of semi-floating grasses, sedges, rushes, and a few small shrubs and are important to alligators for hibernation   

Also within these areas is the famed alligator of the south.  The abundance of water and bird life of these swamps and marshes feed these gators, allowing them to grow to large sizes.  The wild gator grows about one foot a year until it reaches six feet, then growth slows considerably.  The longest lived gators can survive up to 90 years in extremely rare instances and reach 15 feet in length.  Gators over six feet are uncommon but gators less than this are often found in abundance.   During warm summer months when water temperatures are over 70 degrees gators can be found throughout the swamps and marshes, anywhere there is enough water.  However, in November water temperatures drop below 70 degrees and gators go into hibernation until early spring when the water warms up again.  Typically, water levels in these wetlands fluctuate with ocean tides and floods coming from upstream.  This is a problem for hibernating gators who need to hibernate in wet areas but cannot be submerged with flood waters.  Because of this, gators hibernate in floating grassy marshlands that float up and down with fluctuating water levels.  Gator hunting is a rather common practice in Southern Louisiana.  The game management agency allows one gator to be harvested per twenty acres of wetland.  I've been told this is a major meat source for rural Louisianans.  I personally have eaten gator fried, as jerky, and as sausage.  Fried gator is rather chewy, but the jerky and sausage are great.  I love both of them.  In-fact, I may like gator jerky better than beef jerky.

A Louisiana alligator found in a bayou.  

Underneath all these wetlands in the sediments is an abundance of oil and natural gas.  Over past decades these natural resources have been drilled and mined out of the sediments, resulting in the wetlands sinking and flooding with more water.  This flooding has killed wetland vegetation and caused the disappearance of  this habitat.  According to some sources an entire football field of Louisiana wetland is disappearing as a result of this every 38 minutes.  Historically, the Mississippi has also snaked its way back and forth across southern Louisiana depositing sediments in low laying areas everywhere it went.  Today, the Mississippi is highly channelized and controlled by the Army Corps of Engineers, preventing this nature controlled movement and deposition of the river.  So when wetlands sink, sediments from the river is not available to raise them back up again.  People from all professions and industries are still searching for solutions to this problem.

The red area of the ocean indicates areas of low oxygen known as the dead zone.  This dead zone is a result of  water pollution brought into the gulf by the Mississippi River.  Picture from Wikipedia.

As the muddy waters of the Mississippi pass through the Midwest and the South, some of the richest agricultural land in the world, sediments and fertilizer are washed into and pollute the river.  The vast wetlands of the Mississippi River delta capture much of this pollution.  As wetlands naturally do, they capture and filter out pollutants from water in an amazingly efficient manner.  However, as some of these wetlands disappear, and being the levels of pollution are so extremely high, much of the pollution works its way through the delta and is deposited into the Gulf of Mexico.  This immediately has the effect of "fertilizing" the Gulf, which may seem a good thing at first.  Fertilization of water by pollution is known as eutrophication, and results in large algal blooms.  Once this algae dies however, the decompose and consume all the available oxygen in the water.  As a result of these low oxygen levels, very little ocean life can survive in these areas, giving it the name "dead zone."  The dead zone in the Gulf where the Mississippi ends currently is the size of New Jersey and has had huge effects on sea life, including the fishing industry.

Sediment pollution causing the dead zone (right side) next to oxygenated waters (left side).

Despite the negative, the wetlands of Southern Louisiana are still a vast, amazing, and relatively healthy functioning ecosystem.  Even in their impaired state these wetlands are still intact and functioning as they should.  Of course, they could function better if the Mississippi was allowed to flow as it pleased rather than be controlled.  With the many towns and small settlements in the area, letting the Mississippi flow back and fourth across the delta would likely destroy many of these communities.  Controlling the Mississippi is also important to the shipping industry.  So simply restoring natural flow is not such as simple task.  Still, even in their present state these wetlands absorb and filter much of the pollution that is carried down the Mississippi as well as provide huge areas for wildlife and recreation.  Without these functions the current dead zone in the gulf would be much larger and have enormous impacts on the fishing industry.

While I was only able to spend one day exploring these wetlands, it made me hungry to experience them more.  These wetlands are an amazing place to which so many people, cultures, plants, birds, and animals call home.  All of these different aspects are tied together forming the diversely rich creole culture.  In the near future, I will be talking more about this creole culture with a post about a historic Mississippi river plantation.

Louisiana Wetlands and the Mississippi River Delta Part 1

A Louisiana bayou in the Mississippi River Delta.  

Louisiana boasts an amazing 40 to 45 percent of the continental United States wetlands.  Flying into, and driving through Southern Louisiana gives you a good sense of the vastness of these wetlands, miles and miles of unbroken soggy earth everywhere.  Water is literally everywhere, there is of course lots of open water, and where there isn't open water there are sopping wet grassy marshes, and where there aren't mashes their are soaked forests.  The air is always full of humidity with a faint marshy smell, no matter where you are at.  I have visited many wetlands in my life, but none compare to the expansiveness and diversity of these subtropical wetlands.

A part from the sopping wet nature of southern Louisiana, the next most obvious feature is the perfectly flat nature of this landscape.  This soaked flat landscape is a result of the Mississippi River reaching the Gulf of Mexico and depositing massive amounts of water and sediment as the river slows before dumping into the ocean.  The Mississippi begins as a small clear stream at Lake Itasca in Northern Minnesota, which I have personally walked across in only a few short steps that only went up to my knees.  Growing up, I also fished the Mississippi River in Iowa where it is a mighty and muddy river.  Flowing southward, the river continues to grow in volume and accumulate more muddy sediments making it "The Big Muddy."  All this water and mud however has to end up somewhere and is deposited in a delta entering the Gulf of Mexico in southern Louisiana.  This deposition and delta forming process has been taking place for thousands of years since the end of the last ice age.  The entirety of Southern Louisiana was at one time deposited by the Mississippi, and today, over one mile of sediment covers the underlying bedrock.

Oak trees draped with Spanish Moss along a higher, drier portion on a bayou.

Along the Mississippi and other distributary rivers flowing out of it, heavier sandy sediments are deposited along the bank.  These sediments form a sort of natural levee elevated above the rest of the alluvial plain.  On these natural levees many species of oaks are commonly found including the Southern Live Oak, Water Oak, and Swamp Laurel Oak.  These Oaks can only tolerate temporary flooding and need to be on dry land adjacent to lots of water, such as next to a river or swamp.  A short distance from the river, the natural levee slopes slowly down, away from the river.  As the slope moves downward, away from the river, the ground becomes increasingly wet.  Maples and Ash grow on this wetter back-slope along with some oaks.  Lower on the back-slope the ground becomes increasingly saturated, often with standing water, here Baldcypress and Water Tupelo grow.  These areas are still high enough on the slope so that they are not flooded for extended periods of time.  Cypress trees can grow for over 1000 years on these sites and grow large "buttress" roots around the base of their stump in order to stabilize themselves for these long periods of time in these soggy loose soils.  All of these trees are draped with often thick clumps of Spanish Moss.  This moss, is technically not a moss at all but rather more closely related to a pineapple, very odd considering they look nothing alike.  These draperies of Spanish Moss are normally tan colored, except for after rainfall when they turn green.  Hanging from trees and blowing in the wind the moss gives the narrow bayous a romantic southern feel, as they decorate the majestic oaks and cypress trees.

Baldcypress trees found in wetter portions of the wetland then the oaks.  

A floating marsh wetland characterized by grasses, sedges, and rushes.  These types of marshes are important locations for alligator hibernation.

Away from the natural levee and closer to the mouth of the river where the water is always flooded, floating marshlands exist which are dominated by grasses, rushes, sedges, and cattails.  Historically, these floating marshes were far more common and widespread.  As they were settled, channels were dug through these marshes and the sediments piled adjacent to the channel.  These new channels formed what are known today as bayous with the adjacent piles of sediments forming vegetation similar to the natural levees along rivers.  These marshes and bayous can have brackish water (slightly salty) or freshwater and are filled with an abundance of life.  Brackish waters have crabs, while crayfish are found in fresh, both of which are trapped for the great seafood the area is known for.  Bass, crappies, drum, gar, and catfish are in abundance in these areas.  A guide told me there are so many fish in these wetlands that if you don't catch any fish, you don't tell anyone.  In other words, there are always fish to be caught, and to not catch any is not typical, and embarrassing.  Birds also fill these areas including waterfowl of all types, herons, and ibis.

This concludes part one of the Louisiana Wetlands.  In our next entry we will cover the famous alligator of these wetlands as well as some of the ecological issues they face today.  

Simply Unique Seaweed

Seaweed is one of the simplest, most unique, and interesting plants.  But calling seaweed a plant is a slight misconception.  Technically, seaweed is not like the land plants we commonly encounter, seaweed is actually an algae.  What's the difference between plants and algae?  Land plants are much more complex, they absorb nutrients and water through extensive root systems, and have vascular systems to distribute these through out the plant.  Algae on the other hand have no root system, instead they have a holdfast, which simply anchors them to the ocean floor.  Instead of a stem, algae have a stipe, which is like a stem but does not contain woody vascular tissue.  Lastly, algae may have what looks like leaves but actually are called lamina because they also lack vascular tissue.  Nutrients, instead of being absorbed from the soil, through the roots, and then transported to the leaves through the stem like land plants, algae directly absorb everything they need directly from the ocean.  Nutrients move from the ocean directly into lamina where it feeds the algae.  One major function land plants and algae have in common though is both harvest light using photosynthesis to produce sugar for energy.

All kinds of algae grow throughout the ocean, the largest and most interesting grow in the tidal zone.  These are distributed by elevation within or near the tidal zone.  Some species are located just above the tidal zone gaining nutrients from wave spray or splash.  Other species only like to be covered with with water for a short time each day so are in the highest portion of the tidal zone.  Others like weak waves and others very strong waves.  Each has their specific preference of conditions.  The largest are the furthest out from shore.  Bull Kelp, for example, can grow in water 100 feet deep with their highest lamina floating on the surface.  Kelp grows with amazing speeds of up to 20 inches in one day during the summer.

An underwater kelp forest.

The following video is great, showing how seaweed is harvested and the type of environment it is typically found it.  I have spent a decent amount of time in tidal areas like this and they are truly amazing places.  Typically, places like these are only accessible during low tide.  A few locations where deeper water algae grow may only be accessible during the lowest low tides which only happen a few days a month or a few days a year.  The waves, ocean, rocks, and great abundance of sea life in these areas is both beautiful and amazing.  At the same time these areas are extremely dangerous and only highly skilled and informed people can experience these areas on a relatively safe basis.  I say relatively because the constantly pounding waves, the rocks, and currents can be quite unpredictable, even to the most experienced.  Larch Hanson, the person harvesting the seaweed, is amazing at how he handles this dangerous environment, making it appear quite easy.


The Perennial Plate Episode 76: Seaweed Man from Daniel Klein on Vimeo.

Seaweed is truly remarkable for the number of things it can be used for.  Of course, most people know that sushi is wrapped in seaweed, specifically Porphyra.  Seaweed salads available in Japanese restaurants are typically made from Wakame.  Agar and other gelatinous materials are also produced from a variety of different alga.  It is also an excellent source of many different nutrients that are not typically present in other foods, but especially iodine.  This great diversity of available nutrients also makes it an excellent organic fertilizer.  Research is also being done on how to efficiently use seaweed to produce bio-fuels.  This all makes for a booming but relatively small seaweed agricultural industry that is still in its infancy having only started about 50 or so years ago.

More information on seaweed: Maine Seaweed: the Seaweed Man

Albuquerque Rio Grande Botanical Garden and Aquarium

I recently made a quick trip through Albuquerque and was privileged enough to stop by the Albuquerque New Mexico Rio Grande Botanical Garden and Aquarium (click here for website).  The Aquarium is on the smaller size but has a number of great tanks.  The shark tank was quite impressive and I enjoyed their native fish displays.  I also enjoyed botanical garden, especially the Rio Grande Heritage Farm with their livestock, large gardens, flowers, and orchard.  The orchard was especially impressive to me.  Anyway here are some pictures of the aquarium and garden, well worth a visit is you live in the area or are passing through.  This is an absolutely wonderful place to learn all kinds of things about plants, animals, fish, and farming. 

Prickly Pear Cactus flower

Apache Trout

Purple Cone Flower

Coryopsis

Butterfly garden

Lily pad

Rio Grande Heritage Farm

Rio Grande Heritage Farm

Eastern deciduous forest bottomlands

Pulpit Rock in the foreground and the Upper Iowa River floodplain and bottomlands in the distance.  Northeastern Iowa near Decorah.

Eastern Deciduous Forest bottomlands can be quite the interesting place to visit.  If you were dropped off in the middle of one of these forests during the summer probably the first thing you would notice would be the mosquitoes.  Secondly, you would notice thick vegetation and in most cases the soggy ground.  Some areas would be dry but most areas would be at least moist, if not so muddy that you could never imagine walking through them.  As you tried to hike out of the forest you would find yourself bushwacking through thickets of stinging nettles and poison ivy.  You would also walk through tall grassy areas or cross over nearly barren ground due to the thick tree canopy above or recent flooding that killed ground vegetation.  

These forests are always quite flat except for depressions where small ponds or drainages form.  This flat structure is a result of decades to centuries of river flooding (or more).  The nearby river is what defines the bottomland forest and makes it a quite inhospitable place.  As any river flows it erodes away soil and deposits it elsewhere, especially during floods.  Typically this eroded soil is deposited where the water slows along the river banks.  Year after year, flooding deposits sediments along the river bank resulting in the formation of a floodplain, which is where bottomland forests are found.  A newly formed floodplain will first be colonized by ragweed and grasses.  If it is stable and isn't washed away by river flooding, Willows will begin to colonize it, often forming quite dense stands.  Cottonwoods will shortly follow.  Very few of these trees will ever reach maturity.

A dense stand of Willow and Cottonwood trees.  The earliest stage of bottomland forest succession.  These trees require full sunlight to grow.

If the area is heavily disturbed by flooding year after year the stand of Willows and Cottonwoods may persist.  But if the area is slightly drier and not as strongly disturbed for many years other trees may move in like Ash, Elm, Swamp Oak, Walnut, or Basswood.  If the floodplain remains stable even longer, many decades after these trees are established Maple trees will become the dominate tree.  This progression of tree species is called succession.

Not the greatest picture but shows a dense thicket of Maple trees (left half of photo) growing under the canopy of more mature Ash trees (the larger stump on the right).  Most of these Maple trees will die, but due to their ability to grow in shade, the Maples will one day replace the Ash trees.  One day this Ash tree forest will be a Maple forest.  This is an intermediate stage of Bottomland Forest succession.  This bottomland is located adjacent to the Cedar River in the Wikkiup Hill Natural Area in Eastern Iowa.

A Bottomland Eastern Deciduous Forest composed almost exclusively of Silver Maple with a few Elm, Sugar Maple, and Cottonwood trees.  This is nearly the latest stage of bottomland forest succession.  This bottomland is also at Wikkiup Hill Natural Area in Eastern Iowa.

As you can probably tell from the description, the Bottomland Forest is not somewhere you would want to pitch a tent and camp out for the night due to its in-hospitable nature.  However, this wild in-hospitality is what makes it so interesting and exciting to explore.  Exploring it with a good amount of bug spray, some waterproof boots, a hiking trail, and the ability to identify Poison Ivy and Stinging Nettles makes these areas more accessible.  Not many people brave the mud and bugs of bottomlands so they become tremendous wildlife refuges.  Deer, Turkey, Raccoons, beaver, otters, muskrat, ducks, and a whole host of birds are in abundance in bottomlands.  On recent hiking trips I saw several Whitetail Deer fawns in bottomlands and absolutely none in drier more hospitable upland forests.  

An ephemeral pond in a Bottomland Forest left over after flooding.  Ephemeral ponds are temporary in nature, forming in spring with flooding and drying out later in the summer.  These ponds are home to a wide variety of organisms including, salamanders, frogs, toads, and ducks.  Picture is from Cedar River floodplain located at the Indian Creek Nature Center in Eastern Iowa.

Based on the above description of the bottomlands you can probably tell that these areas form quite diverse habitats.  Annual flooding disturbs some areas more then others and makes some areas wetter then others.  This creates a variety of different forest types in differing stages of succession and a variety is different water habitats.  All kinds of interesting animals can be found in their preferred habitat type (also called a niche) and the greater diversity of habitats, the greater diversity of organisms you will find.  Yet another great reason to explore the bottomlands.  

Accidental aquatic biology in an aquarium

In the biology lab we have had an aquarium for keeping aquatic plants for probably about six years.  All was going well until about two years ago when we purchased some aquatic plants from a new vendor.  These new plants were unfortunately inhabited by a few hidden snails.  Resulting in a snail population explosion in our tank.  The snail population probably peaked somewhere around several hundred snails in our ten gallon tank.  Large bunches of the aquatic plant elodea could be eaten in a matter of days by these snails.  We fought this snail population for about two years by trying to starve them to death, but ultimately it was unsuccessful. 

Snail on the side of our fish tank.

Snail eggs on the side of our fish tank.

 Thinking that maybe snails were coming in on each of our shipments of aquatic plants we tried a new vendor.  Well this third vendor was worse than the previous one.  Snails still proliferated in the tank but apparently mosquito eggs or larva, and some sort of daphnia zooplankton came in with our latest shipment of plants.  This resulted in a rather large swarm of mosquitoes in our tank and huge numbers of daphnia swimming around in the water.  Fortunately, we had a good lid on the tank so the mosquitoes did not escape.

Mosquito larva in our tank.  The tiny dots are either sediment or tiny daphnia swimming around.

As a result of all this we finally had to dump the tank out and start over.  But in the process we got to observe some pretty interesting things: snail and mosquito life cycles, exponential population growth and subsequent crash, control of food on the snail population, and even some microbiology.  A pretty cool accidental aquatic biology experiment if I don't say so myself.  Next time we are going to stick with our first vendor, and if we have the same problem I think we'll introduce a small fish into the tank to see what happens.

Simple aquatic insect sampling

Plastic mesh bags like the one above can be filled with leaves and placed in a pond or stream in order to collect aquatic insect larva and nymphs. 

For a number of years now we have been assessing local aquatic insect populations through a rather simple plastic mesh bag method.  The mesh bag, which is slightly larger then a sandwich bag, is filled with leaves, the openings tied shut, and then sunk in a few feet of water.  The bag can be submerged in any type of body of water, whether moving or still, the important part is that you have the ability to retrieve it.  It doesn't have to be deep to produce good results.  Also, make sure you place adequate weight in the bag (a rock will do) so the bag doesn't flow away.  Once the bag is placed on the bottom of a body of water it becomes habitat for immature insects as they colonize it over a period of a few weeks.  After a few weeks the bag can be opened up and the bugs sorted out out from the leaves.

Directions:
1. Obtain a mesh bag of some type.  Mesh bags that onions come in will work well.
2. Cut the mesh bag down to a more manageable size.  If you end up with multiple openings you can simply tie them shut.
3. Fill the bag with dead leaves.  Be sure not to pack them in too tightly.
4. Place a rock in the bag and tie it shut with string.
5. Submerge the bag in a few feet of water at most.  It is important to have the ability to retrieve it.  If it is too deep you might have to swim to get it.
6. Leave the bag underwater for about two weeks.
7. After about two weeks, retrieve the bags, open them up and carefully sort through the leaves to find small aquatic insects.  When transporting the bags from the body of water to where the leaves will be sorted out be sure to keep the entire pack in water.  If the leaf packs dry out the insects will die.  To avoid this place your leaf pack in a one gallon plastic bag or a bucket that has enough water in it to submerge everything.

These leaves are the contents from one of our leaf packs.  The leaves are taken out of the pack and sorted out carefully in trays or bowls filled with water from where the leaves were submerged.  Using a magnifying  glass, tweezers, spoons, and cheep paint brushed help in sorting through the leaves and looking for insects.

Sorting through the leaves in the bag can be quite interesting.  There should be all sorts of tiny creatures swimming around.  A magnifying glass, tweezers, spoons, and paint brushes help in carefully sorting through the leaves to find insects.  Most of the insects will likely be less then a half inch in length so look closely!

In the ponds around Phoenix we find an abundance of mayfly nymphs, dragon fly nymphs, scuds, and fly larva (diptera or "midges").

Mayfly nymph

Scud

Dragon fly nymph

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.