On Wednesday morning, Josue, Cici and I introduced a group of students involved in the creation of a school mural to the Bronx River Forest and the Bronx River. On our reconnaissance of the area just prior to the walk, we came across an egret foraging while standing on a pile of recently accumulated detritus. The newly expanded island in the s
tream caused eddies and small ponds that offered great hunting grounds for the egret. As we watched, the egret moved its long, muscular neck almost imperceptibly before jabbing it into the water and coming up with a slender fish about 3 inches long ( a tessellated darter?) Egrets and herons differ from storks and flamingos in that their necks are hunting tools. The powerful muscles allow them to thrust down into the water in search of prey. You can best note the difference when in flight as the birds with the stronger muscles coil their necks back while those that just use their necks to reach down and filter the water fly with their necks stretched out straight. We kept as quit as possible and left the egret to finish its fishing somewhat in private.
But what kind of an egret was it? A Snowy Egret? A Great White Egret? The answer is in the beak and the feet. While the Great White Egret is larger than the Snowy Egret, size sometimes depends on perspective. This is a Great White Egret due to the fact the beak is yellow and the legs and feet are black (not the best view of the feet here), while the Snow Egret has a black beak, black leg and yellow feet. They can also be distinguished by hunting style. The Great White is patient, waiting for prey to come into range while the Snowy will actively kick up the bottom in an effort to stir up game. Makes you wonder if there is some connection between the Snowy’s style and the natural selection that gives it its yellow feet.
DG
July 9, 2009
Thinking about beavers does not conjure up images of urban areas. Quite to the contrary, as a matter of fact, and people do not often associate the Bronx with beavers, but we do have one: at least one.
Since the first bite marks were noticed over two years ago, the now named Jose the Beaver has been little seen but his presence has been noticed. In the section of the Bronx River that stretches between the New York Botanical Garden and the Bronx Zoo, trees ave been gnawed and felled, and two lodges and a burrow have been identified has beaver housing. Being largely nocturnal, Jose works while the two establishments are closed and he (she?) is out of sight of the casual passersby. Photographs were taken with trip cameras by WCS, and a writer for Outdoor Magazine claims to have infrared photos but nobody has seen them. A staffer at the Bronx Zoo did see Jose one morning and placed Jose among the biggest beavers he had ever seen. Running between 30 and 70 lbs, the guesstimate weighs him in around 50 lbs.
If you put yourself on the list of those who have not seen Jose The Bronx River Beaver, you may now remove yourself from that list. On the morning of June 12, 2009 Jose put in an appearance at Drew Gardens as the participants in Bronx River Crossing made preparations to launch their watershed representation. Chris Kannon was able 
to take a series of shots as Jose swam leisurely upstream before lumbering out of the water to walk under East Tremont Ave. Some of us noted that he seemed sluggish or even disoriented. Of course, having never seen a beaver, maybe they always look that way. On more than one occasion the same has been said about me. Maybe it was the salty water where he was swimming? Drew gardens is at the top of the estuary and has been found to have levels of salinity up to 8 parts per thousand (oceans are 30-35 ppt and freshwater is usually < 0.5 ppt) When the dying beaver was found last year in the East River on the day of the pope’s visit, it was reported that, while that beaver had already been sick, it was probably the brackish waters of the East River that finally did him in. Could Jose be on his way to a similar fate? Could the stresses of life in the zoo and the garden be such that he is being chased down stream and into a perilous situation?
Jose came up again in a discussion that our Executive Director had with a local fisherman on Saturday in River Park, just south of the last dam on the river and the zoo. When she mentioned the beaver having been seen just to the south, the fisherman nonchalantly replied, “Oh yeah, I see that beaver all the time down here.” Could it be that Jose is putting himself in danger on a regular basis? Why would he chance forays into brackish water unless he has a death wish or is suffering from dementia?
In May of this year, W. Gregory Hood, Ph.D. of the Skagit System Cooperative published a research paper entitled The Overlooked Ecosystem. Dr. Hood had set out to study the distribution of Sweetgale (myrica gale) in the estuarine section of the Skagit River in Seattle. While he did find the sweetgale, he also found that the estuary was frequented by beaver from the fresh water section of the river. Dr. Hood explains that beavers are known to make use of estuarine areas with salinity levels as high as 10 ppt. Being true vegetarians, they are in search of those trees that will fulfill their appetite while providing the needed nutrients. If the trees in question are along the banks of brackish water, the beaver is prepared to go there. Beavers rarely forage more than 100 yards from the stream they call home which makes upstream and downstream travelling the normal event. Jose is probably in search of food and a quiet place. In most land conflict events, beaver will look for new foraging areas. This explains Jose’s “bizarre” behavior. It was our lack of understanding of normal behavior that made his acts seem bizarre.
But Dr. Hood also raises some questions that are pertinent to our river. Hood makes the connection between the salmon that use the river for spawning and the beaver that rework the habitat in the estuary and beyond. Being tidal, some estuary sections can become quite shallow at low tide. While the beaver may be in the area to forage, an effort may also be made to dam up small areas, causing tidal pools that will provide safe harbor when the tide runs out. Perhaps coincidentally, these tidal pools also provide a safe zone for salmonids in the area. Being that the beavers prefer somewhat deeper water, the pools are deeper than the areas where wading birds generally will hunt. By providing for personal needs, the beaver helps a multitude of other organisms. While we do not have salmon on the Bronx River, the return of the alewife herring and the catadromous eels fill a similar niche. Both would benefit from a tidal hideout at low tide.
And just what is Jose feeding on in the estuary? It will mean some kicking about in the area, but while beavers preference is for aspen and poplar, they will go for whatever is available when necessary. In that area there are willow trees which are always a part of the diet, but perhaps this new understanding of the range of the beaver and its possible utility can become a part of th present converstation about the soon-to-begin construction in Starlight Park, just south of the Cross Bronx Expressway. From drew Gardens south, the river is armored on both sides with rip rap, leaving the banks barren and lifeless. Dr. Hoods research found that trees growing along the banks of the river did so above the tidal zone, though they did not grow in soil. Instead the trees were able to take root in the woody debris that washed down from upstream and became lodged on the bank at high tide. Perhaps a consideration in the lower Bronx River would be to provide such woody debris. At the present time most woody debris cannot make it down stream due to the dams that block the river at certain point. In some upstream areas, logs have been cabled to the banks as a form of bank stabilization. The Section of the river between Drew Gardens and the south end of Starlight Park needs little bank stabilization due to the rip rap, but taking the same simple idea may provide a landing zone for seeds that can then provide a food source for beaver and create habitats for other unexpected guests.
DG
Cool links:
http://books.google.com/books?id=-xQalfqP7BcC&pg=PA295&lpg=PA295&dq=beaver+favored+diet&source=bl&ots=XOlaFu5796&sig=kBq_s3ePD5K2dJ2eg1exkObBNUE&h
l=es&ei=IdRKSufeIofCNu7v4KoB&sa=X&oi=book_result&ct=result&resnum=1
http://www.wildlife.state.nh.us/Wildlife/Wildlife_PDFs/Beaver_control.pdf
http://www.skagitwatershed.org/rpapers_overlooked.html
Tagged: beaver, bronx river, estuaries, Hood, Skagit July 6, 2009
On July 18, 2008, the Bronx River Alliance placed more than 350 stormdrain markers (above) in Bronx River sewersheds, HP-007, HP-004, HP-009 and HP-008. Support, in the form of funding and ten energetic volunteers, for this project was provided by Goldman Sachs. Thank you to all of the staff from both the Alliance and Goldman Sachs who braved the extreme heat in the name of stormwater education! The Alliance aims to have a total of 500 markers placed by the end of August. Please visit the Storm Water Infrastructure Matters Discussion Forum to discuss stormdrain marking in more detail.
Tagged: bronx river, stormdrain marker, stormwater July 28, 2008
When my father would tell me that I was dense, I did not take it as a compliment, but I did not quite understand the insult either. It did not occur to me that what he meant to tell me was that I was incapable of learning, stupid, even, because I knew that for my father, to be dense was to be a jackass: stubborn. But density is oh so much more. There is a certain power in density, mass divided by volume, in certain circumstances that my father may have, in some askew manner, been actually keying me in on.
In the world of our river, density comes mostly in to play in the interplay between salt water and fresh. If you just consider the comparison between a glass of fresh water, and a glass of water of the same volume into which a table spoon of salt has been added, it is plain that the added salt would make the water weigh more and, therefore, be more dense than the glass of fresh water. But water is water right? So when salt water meets fresh, they should mix and find some medium between the two, right? This is true, but the mixing is not instantaneous. The variables of density, temperature and flow affect the time that it takes for the solution to find this medium point.
There is a fun way to test this effect. You will need four glasses, two of which are filled with water, blue and yellow food coloring and ½ cup of salt. One glass of water will remain as is, but into the other you should add the ½ cup of salt. Should the salt not dissolve entirely upon stirring, you can heat the water slightly in a microwave, stirring occasionally until dissolved. Add 4 drops of yellow food coloring to the fresh water, and 4 drops of blue to the salty water. Pour half of each color into one of the empty glasses so that you know have a two half glasses of yellow (fresh) water and two half glasses of blue (salty) water at approximately the same temperature. Slowly add the salty water to the fresh and ved versa and compare how the two mix and become another color or find where you can see where the two remain separate. If you have tries the experiment, or perhaps if you have not, you will note that the salty water tends to stay towards the bottom of the glass. The same happens in a tidal estuary such as in the Soundview area and farther upstream, only instead of water being added from above, you have two walls of water moving towards one another. The salt water is carried upstream by the tides and the fresh water is carried downstream by gravity. There is a point where these two meet and it is called the salt wedge. The Denser salt water pushes under the fresh water, settling towards the bottom, as the lighter fresh water floats over the top.
This wedge can stretch for miles as it does in the Hudson, or it can be much more vertical if the flow of the river is equally matched by the rise of the tide. In the case of the Hudson, the salt wedge is carefully watched since Poughkeepsie gets much of its drinking water directly from the Hudson. If the salt wedge runs too far north, the flow is increased to push it back down south. Sampling the water at different depths will show the differing salinities.
Fresh water means less than .5 parts per thousand (ppt) of salt, while brackish water is between .5 ppt and 17ppt, and oceans average 35 ppt. Most estuaries, like the Bronx River Estuary, are brackish. At our last monitoring of Drew Gardens miles above the mouth, Sally found2-3 ppt salinity from a surface sample. As a I walked upstream to get a few pictures of The Phipps Youth Employment Program students that were being introduced to water quality monitoring, I saw a nice size blue crab crawling across the bottom of the river in an area were the flow was quite slow.
I thought that the water would be dangerously low in salt for this creature which thrives 10ppt-25ppt but there could be mitigating factors. One is that the test we had done was surface which means that towards the bottom it could have been a little more salty. There is also an interesting study from 2005(POSEY Martin H. (1) ; ALPHIN Troy D. (1) ; HARWELL Heather (1) ; ALLEN Bryan (1) ) that discusses the tendency for juvenile blue crabs to seek areas of lower salinity(3ppt) in the summer and the fall. The theory put forward by the authors is that they are actually looking for waters safer from predators since salinity and predators were positively related. In any case, it shows the river’s improvement and, should this crab not be atypical, demonstrates the importance of this part of the estuary to all waters down river.
Dad may have been right about my being dense, but now I know that density can also have its advantages.
DG
Tagged: blue crabs, bronx river, salt water, salt wedge July 21, 2008
As a student, the situation appeared quite unfair. I always dreamed of giving the teacher a test and then enjoying marking all of the incorrect answers. As a teacher, I took no joy in the marking of tests or work that was incorrect. Even in a question as straightforward as, “ Four students share a cake equally. What Fraction does each student eat?” I gave credit to Krishad’s answer of “One fifth.” “Simple,” he told me, “They saved a piece just in case another person showed up.” Right and wrong answers can really be a question of perspective.
Last week I spent a day in Washington DC “grading” teachers’ papers with two others. Unfortunately there could be only four correct papers out of the fifty that I had to go over, and no matter what the perspective, that was all that could be right. We were one of eight panels choosing the next 30 teachers that will travel to the Galapagos Islands this November as a part of the Toyota International Teacher Program. There were a record 900 applications from all over the US from classroom teachers from 6th to 12th grade, and teachers of all subjects. It was our charge to decide who would “pass” on to the trip of a lifetime, and who would not. While I felt privileged to be asked to participate in the process, I did not relish the idea of giving what would turn out to be a failing grade to those who would not be visiting Las Islas Encantadas.
The process starts with the staff at iie perusing the entire application for completeness. Not following the basic rules of requirements and word counts, and submitting all the requested information. To be fair to all, the rules must be followed strictly. They then take a slightly closer look to see if anything is just outrageous such as “ I will bring back a Galapagos Tortoise and a Marine Iguana to use in a travelling presentation to bring to the fore the importance of conservation.” But the reviewers at this stage are fairly lenient, leaving most decisions of merit to panelists like myself.
At the panel stage, three people, usually including one teacher, somebody in an environmental field, and somebody from an international organization, are given 50 applications to read and rate. For this particular application, the four sections were: personal statement (why you should go), Impact statement( how you will use what you learn), a lesson plan( how you present environmental issues in a hands on manner in your classroom), and reference letters. The most heavily weighted parts were impact statements and lesson plans, but the personal narrative would often inform how you reviewed the other sections. It was not the writing itself that would make a story compelling, but the heart and relevance that the teacher portrayed. Impact statements had to cover students, school and community and be feasible. Lesson plans had to be hands-on, innovative, even if you admit getting the idea from somewhere else, and extendable into various disciplines. It also helped to write in the future perfect, leaving out the maybe’s and might’s.
Strange as it sounds for a trip to what people consider a science teacher’s dreamland, being a science teacher did not work in your favor. Toyota wants environmental education to be interdisciplinary and requires a diversity in subject matter taught by the teachers that are chosen. Almost sixty percent of the applicants taught science. When you consider that a high estimate would be fifteen science teachers, that means that the science teachers are vying for, at best, a one in forty spot. Teachers in any other discipline are up against the odds of one in twenty. I don’t gamble, not even on a one dollar lottery ticket, but my money would be on the teachers of other disciplines.
What it finally came down to was a fight for somebody that a panelist took on as cause. You said to yourself, “This person not only deserves this trip (All really did), but would be an asset to the other US teachers, the galapagueño teachers, the Toyota program, and their school and community.” Then we had to duke it out, give in a little and hope that others believed your arguments.
When all was said and done, we chose a stellar group to take advantage of the program, but had to let go an equal number that were on a par with them. Bittersweet is one way to describe it but the biggest discussion on the way out the door was the applications were all amazing. There were twenty people that I wanted to contact immediately to share ideas and use as resources. For privacy, however, all materials that I was given were destroyed on site, and I have to hope to find those people by happenstance at a later date.
So I got my wish: To grade teachers papers. Unfortunately I could not listen to the explanations as I could with Krishad. But, for those that were not chosen, there will be another round soon enough, and all that can, should apply.
DG
June 26, 2008
Home Depot might not seem like the place to go in search of an epiphany about the need to serve many communities, but epiphanies don’t like to be pigeon holed. I walked through the aisles of Home Depot, searching for items of comfort for the beginning and the ending of life. These items add safety to the surroundings of my loved ones and some feeling of comfort to me. For my 9 month old daughter, I searched for outlet covers and corner bumpers. For my parents I bought a banister for their steps and support bars to help them get in and out of the shower. 80 years separate my two clients, yet their needs are quite similar, and my desire to aid their respective communities is virtually the same for both of them.
As often happens, a decision made to correct an earlier mistake or to provide access for one group that had been previously ignored can benefit many people. A very clear example is for the benefit offered to parents with strollers, bicyclists, and pullers or pushers of carts every time they mount or dismount a sidewalk. Those little sidewalk cut-ins that make the transition smooth were designed to aid the disabled in ADA of 19–. That decision made many lives better.
Two new parks have been opened in Hunts Point in the last year. Ostensibly, the parks were opened to offer the local population access to the waters that surround them for recreation and relaxation. But it may and should grow into something much more.
All along the Bronx River, we are working towards making the river itself and its adjoining environs more accessible to the thousands of school children that live nearby or have heard about its history. The combined efforts of the Education Program and the Recreation Program offer ideas and opportunities to teachers from the area, ranging from a canoe trip with a dissolved oxygen lab to a simple, “Yes, you can walk around in that area.” The teachers are thankful for the support, and the students express their gratitude with their keen interest. About thirty of those students came together on Thursday, June 5th at Hunts Point Riverside Park for the Bronx River Student Symposium. They showed how they are learning about water quality, the wildlife and restoration of the river. Incredible has it sounds, students came on a day off from school to share what they feel is important about the river; Their Bronx River. The access to the river has turned on something in these students far beyond the science or environmental and social issues that they discussed. The students were the ones teaching those that were present about the river. They showed they own the issue and the place, and they are poised to take over. Nothing could make a teacher happier than to have a student move beyond them, hopefully make them superfluous.
The desire, no; the feeling of responsibility to bring about one change for one person or group that need can often have a greater effect on groups beyond those targeted. The Bronx River Alliance and the groups that we partner with have tried to increase access to the river for teachers and students, and the students will take it on to the world. In the case of the banister that I put up for my octogenarian parents, the first one to use it was nine month old daughter. The first person to grab on to that banister was not the intended user, but that smile of satisfaction that came from the safe feeling of the sturdy oak rail told me that I had done the right thing.
DG
June 8, 2008
On Saturday, May 10th, 2008, I joined 164 paddlers and passengers in the launching of 70 canoes to take part in the 9th Annual Amazing Bronx River Flotilla. Though I’ve been told many times how much fun the Flotilla is, it’s only after undertaking the adventure myself, that I recognize it as one of those things – like democracy itself – that can only REALLY be understood by directly participating.
From the Flotilla’s “put-in” at Shoelace Park, all along its journey through the forests of Bronx Park, coursing onward through the river’s industrialized lower reaches and grand finish at Hunts Point Park, it was a remarkably varied 7.5 mile paddle on a glorious day in the spring of the year! Framed by a rousing start and finish in NYC parks, the Flotilla mixes an inspection of the river’s returning ecological health with the feel of a music festival, alumni reunion, block party, street fair and sprawling, affectionate, all-inclusive family gathering.
If the energies of restoration and renewal along the river are striking, it is the experience of sharing all of that with so many Bronxites of so many generations and neighborhoods – with politicians and poets and planners and people from throughout the city and Albany and beyond – that fills the Flotilla with its ultimate celebratory excitement.
Teenagers from Rocking the Boat, Youth Ministries for Peace and Justice, The Point, Sustainable South Bronx, Mosholu Community Center, Christadora and Urban Divers all took part in the day – some as volunteers partaking in “service learning,” others to strengthen paddling skills or simply enjoy the river. In fact, it would be hard to imagine a better opportunity to expose young people to the river in all its dimensions than the Flotilla, which is also well represented by leaders from NYS-DEC, NYC Department of Parks and Recreation, NYC-DOT and other government agencies.
When two canoes flipped during rapids encountered on this Flotilla, other vessels quickly stopped to help. In addition to the presence of patrol boats positioned along the river, poised to pitch in and aide a struggling paddler, the communal spirit of the day ensures that more experienced canoeists will step in when needed. For among the life lessons that any good canoe trip teaches is the almost invisible axiom – although life’s trails may present you with troubles now and then, with some determination, and perhaps some help along the way, you can invariably right yourself and continue along.
Who can describe the peculiarly urban joy of careening down the Bronx River rapids by canoe, meditating on midges gliding across the surface of the water, plucking a leaf from an overhanging branch for later identification, observing not just egrets, sandpipers and ducks but bison and tigers. On no other river could the pleasure be so keen at coming upon an unanticipated swan or clump of arrowroot by the shore, or in hearing a peacock calling from a distant tree as we pass. Where else can you portage your canoe at an old snuff mill or look up to see the cars of the monorail bridging the river ahead with all the charm of a toy train set crossing in the distance?
Yet, of the many views and myriad perspectives of the river offered by the Flotilla, there was no vantage point more vivid than the view from the bridge as we drove away from Hunts Point Park, and one could see the river stretching out before us, like the future itself, a half dozen of the last canoes eagerly paddling towards the landing where the music was rising…
Lisa Garrison, New York City Environmental Fund,
Hudson River Foundation
May 20, 2008
If I am in my neighborhood but not within sight of my apartment building, and I hear a fire truck wailing, I am sure that I have left the kettle or a pot on the stove and those trucks are now rushing to extinguish the fire I have caused. With that in mind, consider how I felt when I heard about the beaver that was dragged from the East River just before the cutting of its thread of life. Not only did I believe that that beaver was the José from the Bronx River, but as the person that is somewhat responsible for keeping an eye on the health of the river, I felt that I had killed him. “The police pulled him from the East River,” Warren from the Friends of the (Bronx) Zoo (FOZ) said, “but then he died.” What I heard coming from his lips was, “You did not sufficiently administer the Bronx River Stewards; your negligence allowed him to die.” If the beaver leaves or dies on my watch without my being able to show why, then I have failed the river, the Bronx, and the world.
When a body is found, it must be identified. I have never met José (Josefa?) So I could not physically identify the body, but I have seen signs. It seemed rational to me to want to know for sure, so I threw out the suggestion that the beavers incisors should be measured for width and I could compare that width to the evidence I could find along the river, and possibly eliminate José from the list of possible victims. My inquiries, however, went unanswered. I can only imagine that the people and institutions that received my e mails believed that I was just a crackpot, but the exit of the animal whose arrival last year was touted as proof of the river’s revival, should also be seen as raising questions about sustained improvement. Recent finds and anomalies raise just that issue as they do the importance of regular monitoring.
On Monday, May 5, 2008, as I met with the FOZ for their weekly water quality monitoring. I decided to wander upstream. I checked first some of the signs that I had seen early last winter, and found no changes. I’ve come to believe that José is a juvenile, an adolescent, like my son. There is nothing scientific in this just that like my son, José prefers a buffet to a sit down meal. He snacks, sometimes heavily, and then moves on. At the known snack stops, I didn’t notice anything new. Then I saw a few new, white chew areas. And then a few more. Finally I found an area that still had some bits of fresh chips clinging to the tree, chips that would have been washed away in the previous night’s rain. Walking down to the bank of the river, I was also able to find tracks in the mud. There were various small prints, and some that looked like goose tracks. I learned that those “goose tracks” were most likely the back, flipper-like feet of the beaver. The combination of evidence seems to point towards life, not death.
I feel better knowing that I have not had to bear witness to such a tragedy at this stage in my stewardship. José lives. I am still sad for the beaver that did pass away, and feel that it is very important to discover the reason for its mortality. I pledge, before all, to do my duty, to the river and the Bronx, to keep as close an eye on the river as possible, to better serve the amazing stewards that volunteer their time to gather data about the river, and work towards a better river for all.
May 8, 2008
Knowledge is like a virus in that once you learn one thing, it is hard to stop it from stretching into learning another. The simple act of reading or listening can cause a word or an idea to hang in your mind until another comes across and makes the connection permanent. It is as though we are all our own zone of proximal development. On April 23rd I was lucky enough to work with the Friends of the Bronx Zoo to, ostensibly train or re train 7 people in water quality monitoring. The zoo has a history of monitoring several FOZ were interested in getting back into the flow. As I spoke about pH and buffers, I had a fairly clear idea that I knew what I was talking about. As I added water to the pH 4 buffer, I wanted to show how to dilute it and raise the pH. Instead, it actually went down before hovering back around pH 4. “You have just proved that it is a buffer,” Dione, one of the FOZ said. “That is why it is a buffer, and not just a solution with a pH of 4. It is making sure that the pH stays stable.” I thanked my student and then moved on. Dione, as it turns out, has a PhD in chemistry and should have been the one speaking to the group. But, that little thing she pointed out to me sent me off to look for more information.
One of the parameters that the Bronx River Stewards measure is pH. Most people know something about pH and its relationship to acids and bases, but just what does that mean, and why is it important to our river? What does the pH level tell us?
The term pH is derived from the French puissance d’hydrogene, meaning “strength of hydrogen”, referring to the hydrogen ion that affects acidity. The pH scale runs from 0-14 with values less than 7 being acidic and values greater than 7 being basic. At 7, there is equilibrium between the two. The scale is logarithmic, with each level having a difference of a power of ten from the other. So pH 5 is ten times more acidic than pH 6.
pH values of natural water vary, but below 5 or above 9 are detrimental to organisms, and normal values range from 6.5 to 8.5. Most aquatic life, however, has adapted to specific pH and sustained change can cause damage to a population.
To counter these changes, natural water acts as a buffer. A buffer resists change, like the pillows that my wife and I pile up to keep my 8 month old away from of the stereo. She pushes against them, put they bounce back, and Bethania cannot change my radio station (NPR builds vocabulary). The Bronx River Stewards use buffers of set values, 4, 7 or 10, to make sure that the pH meter is working correctly. The pH values of these solutions can only be changed by adding a buffer of a differing value. Natural water should react in the same way; using the natural hydrology to create a buffer against change. The problems occur when either a stronger acid (acid rain, pH 5.6) or a stronger base (concrete washout water>12) enters the system and causes a rapid change to the pH level.
But a pH change can be a secondary effect as well. For example, photosynthesis uses up dissolved carbon dioxide (pH 6.3) effectively raising the pH level. On days when photosynthesis is most likely, such as sunny days during the growing season, the pH level of the river may rise. But what appears to be a natural effect may have very human causes. Fertilizers and human waste, both generally acidic compounds which enter the Bronx River on a regular basis through stormwater runoff (CSOs) and illegal sewage connections (Yonkers), increase plant growth and even the algae blooms recently noted on the river. So the introduction of an acid causes a basic reaction. Organic respiration at night produces CO2 thereby lowering pH levels and dissolved oxygen levels, as does the massive decomposition that follows mortality.
The level of pH in the Bronx needs to be monitored closely, not just for the answer the value itself gives us, but for the chain of possible causes of that value that need to be looked into.
Thanks, Dione.
references: http://waterontheweb.org/under/streamecology/09%5Fph%2Ddraft.html, http://www.seed.slb.com/en/scictr/journal/environment/river/is54nyc.htm, http://www.geocities.com/capecanaveral/hall/9111/DOC.HTML
DG
April 30, 2008
Why do we bother teaching science to students? Do we really believe that we are teaching the next Charles Drew? Do we see in the faces of the youth around us some audacity of imagination that just might happen to advance an end to diabetes? The truth is that it is actually true. When you work with somebody who is learning something new in the world of science, some odd duende appears and you believe that this person may just make an advance in the world that will benefit us all. But that is not why science is important; It is important beyond the science itself because of the dialog that you see between the mind and the world that surrounds us. Last Friday I was lucky enough to speak with some of the interlocutors that have been involved in that dialogue at the Banana Kelly Science Fair.
Nic and Carly at Banana Kelly High School have built their ninth grade science curriculum around the Bronx River and water quality monitoring. They have also given students a window onto their world and some of the students have taken that view very seriously. As I walked between the two rooms where the Science Fair was set up, I was amazed at the amount of information that the students had sorted through and had to make sense of in the form of a presentation. There were discussions about salinity, turbidity, global warming and comparisons of the levels of pollution in the Bronx River, the Hudson River, and the Newtown Creek. Just like with adults, the depth of the discussion varied greatly across the classes, but you could feel that the dominant opinion was that the subject merited discussion.
In the interest of full disclosure, Nic and Carly put me in the difficult position of grading the projects that I viewed, a job that they face everyday. I was given a rubric and had to see where on that scale the students stood. This is necessary because the students, all of us actually, need to know that people are looking critically at everything that we say and do. The unfortunate thing is that I wrote all notes on those rubrics instead of in my notebook, besides the fact that I was a little harsh in my grading.
At any rate, many students showed that they had looked deeply into the data and asked, “Why does the salinity level change?” or “What is the relationship between the amount of precipitation and turbidity?” Then they tried to make sense of these numbers, a task they call mental mastication. The data, mostly just numbers and dates, was obviously much more to these young people; they had collected the data, seen the parts of the world they were talking about, and knew that they were talking about their world. The dialogue that they engaged in was intimate which made the information relevant.
Beyond the actual information, the off-the-cuff remarks of many of the students made me really think about what education is really about and how hard it is to judge the understanding of a student. “Maybe,” Said one, “The Bronx River is cleaner because people have been trying to clean it up. Maybe that’s what the Newtown Creek needs.” To be able to see beyond the first view, beyond the numbers and actually bring in a historical perspective is profound and extremely heartening. It is beyond science and into life itself.
I was glad to have been invited by Banana Kelly to this event, but I must admit that I felt a bit like W.H. Auden: “When I find myself in the company of scientists, I feel like a shabby curate who has strayed by mistake into a room full of dukes.” That goes for the students and their teachers as well. And for these dukes, our natural world is their court.
DG
April 21, 2008
Next Posts
Previous Posts
tream caused eddies and small ponds that offered great hunting grounds for the egret. As we watched, the egret moved its long, muscular neck almost imperceptibly before jabbing it into the water and coming up with a slender fish about 3 inches long ( a tessellated darter?) Egrets and herons differ from storks and flamingos in that their necks are hunting tools. The powerful muscles allow them to thrust down into the water in search of prey. You can best note the difference when in flight as the birds with the stronger muscles coil their necks back while those that just use their necks to reach down and filter the water fly with their necks stretched out straight. We kept as quit as possible and left the egret to finish its fishing somewhat in private.
