Dr. Arsuffi: Hello everyone! I hope everyone's having good weather and that you've had a chance to visit one of your rivers or streams lately.

Dr. Arsuffi: It's very, very serious, in the United States, and I think a lot of it is more serious than most people realize. I mean, some of the data indicate that nearly forty percent of the rivers and streams in the United States are too polluted for fishing and swimming. Another indication of problems with our rivers and streams -- and this is not strictly due to pollution -- is that we can look at having thirty percent of the native freshwater fish species in North America are threatened, endangered, or of special concern.

Dr. Arsuffi: Clean waterways are important in a number of different dimensions. The first thing that most people think about in terms of clean waterways is the water we use for drinking and bathing, so clean water is clearly important in that area. And then maybe the next thing we think about in terms of clean water from our perspective is recreation. I think most everybody has a tremendous appreciation for that, and usually in terms of vacation, water is usually one of the destination spots. So, that's another reason why clean water is important. Then there are secondary types of benefits associated with clean water that we don't really recognize, but we are beginning to. For example, waters, in terms of wetlands, rivers, and streams. We now recognize that those particular ecosystems provide what scientists call ecosystem benefits. Recently, economic ecologists have tried to put a number, a dollar number, on how valuable those ecosystem services are for different aquatic ecosystems. The numbers they have come up with are astounding, and I will give you an example: Wetlands. Wetlands are very often integrated with river and stream systems. In the U.S. alone, in the last two hundred years we've lost over fifty percent of our wetlands. But current ecosystem benefits that wetlands provide are valued at four trillion dollars annually. One of the benefits that wetlands provide is helping to clean up pollution and control floods, before it gets into our rivers and streams. Clean water is a critical component of biodiversity; the unique flora and fauna, the animals and fishes and plants and algae and bugs that live in our rivers and streams.

Dr. Arsuffi: There are a number of ways one can help save endangered species. One way to help save endangered species is locally. Find out whether or not any endangered species occur in your local region, or state. The way to find out this information is to go to the webpage for the U.S. Fish and Wildlife Service. Most states have environmental agencies that track and monitor endangered resources in their state. For example, here in Texas, Texas Parks and Wildlife Department examines endangered species issues. So first find out what your endangered species are, find out why they are threatened or endangered. For most endangered species, Fish and Wildlife Service puts out a document that's called a Recovery Plan. I believe that a lot of these Recovery Plans can be found on the Fish and Wildlife Service webpage. In the Recovery Plan, species are described in terms of their biology, ecology, and natural history, and there's a list of threats, and those threats may be pollution, habitat fragmentation, exotic species, and so on. In those Recovery Plans, there is also a section describing ways to minimize or eliminate threats to the species. In that section is where you can probably find information on that particular species, what is needed to restore the population sizes to non-threatened status. I guess, to help save endangered species -- and this is something that everyone can get involved with -- is public awareness. Most citizens, if they hear the words "endangered species" they either start running, or they start shooting, and in parts of Texas anyway, endangered species is a bad word. This comes from a lack of understanding, and if you can help the public understand that endangered species often are the proverbial "canaries in the coal mine," then that's a first step at helping to save endangered species. Along with this public awareness, lots of people don't understand that from a scientific perspective, a moral perspective, and an ethical perspective, that an endangered bug, or an endangered plant, is every bit as valuable as our American eagle, bears, and other high-profile species that are on the endangered species list.

Dr. Arsuffi: Creatures that I see in the San Marcos River? We have a rich abundance of aquatic plants in the San Marcos River. The San Marcos River is a very unique river system. Originally I'm from Ohio, and as a boy walking around the woods in the hills of Ohio -- I mean, I used to run across springs coming out of hillsides. These were little tiny things, and as my career developed, and I got to to go Montana, and New Mexico, Sapelo Island off the coast of Georgia, before coming to San Marcos, Texas, and I'd heard of the San Marcos River before coming, and they were talking about San Marcos springs. My vision of a spring was that little trickle coming out of the hillside based on my experiences elsewhere, in Ohio, New Mexico and Montana. Well, the San Marcos springs, which starts right across the street from my office, (surprise, surprise!) comes out of the ground with a volume of water the size of a mid-sized river that you might see in other states. In fact, the San Marcos River is the second largest springs system west of the Mississippi. So that water comes out, tremendous volume, and it's crystal clear all year round, is a constant twenty one degree centigrade, and because of this clarity and depth, there are a lot of aquatic plants growing in the river. My class was just in the river last week sampling, and we collected all kinds of aquatic insects and aquatic invertebrates. Here are some of the unique organisms that live in the San Marcos River: we've got six Federally Listed endangered species, including fish, plants, salamanders, insects, and we've got a crustacean in the river called a giant freshwater prawn, and the prawn is as big as a lobster. We've got freshwater eels, the size of an adult man's arm, that live in the San Marcos River, and to get here they had to travel all the way from the Sargasso Sea, so we've got a rich biodiversity of organisms in the San Marcos River.

Dr. Arsuffi: The best way to make your parents interested in clean rivers is to tell them it will save them money in the long run. If we have clean rivers, then we don't have to pay the extra costs of cleaning the rivers up. If we have clean rivers, we have much better aesthetics. A lot of studies have shown that people that live in communities with clean rivers feel that they have a better quality of life. Clean rivers are an inexpensive source of recreation.

Dr. Arsuffi: Nowadays, there's a variety of ways to monitor water quality. Increasingly, we're getting more sophisticated methods of assessing the quality of our rivers and streams. One of the first techniques for measuring water quality that was used throughout the U.S. was basic water chemistry. Things such as dissolved oxygen, Ph, nutrient levels, and so forth. And what aquatic scientists discovered is that while those methods were good, they frequently missed pulse events that polluted waters. So increasingly now, we are looking at biological measures to determine the health of our rivers and streams. Biological measures such as the composition of bottom macroinvertebrate communities, or the composition of fish communities, are good indicators of water quality. The advantage that they have over the chemical methods is that because of the length of their life cycles, they can actually integrate past pollution events that are reflected in community compositions. Now, most state agencies use some sort of a rapid biological assessment, or some sort of index of biological integrity, in addition to water chemistry, to measure water quality. Many states now have water quality standards that are based upon biological communities living in stretches of rivers and streams. The step that needs to be taken, if water quality is found to be deteriorating, is to find the source of the deterioration. And there are two broad categories of pollution that affect rivers and streams. The first type of pollution is called point source pollution. Point source pollution occurs when there is a single discharge point of water entering a river or stream. Classic examples of point source pollution occur from sewage treatment plant discharge. The second type of pollution you can identify affecting rivers and streams is called non-point source pollution. Non-point source pollution means that water that runs over landscapes and enters rivers and streams does so at no single distinguishable location. Non-point source pollution can enter the stream from either side of the river for the entire length of the river. And, examples of where you would find non-point source pollution would be rivers and streams that pass through agricultural regions. Those terrestrial watersheds in landscapes in agricultural situations typically have a lot of fertilizers, pesticides, herbicides, and other chemicals -- and every time it rains, those chemicals are picked up in runoff, and enter rivers and streams in a variety of locations. Now, which is easier to clean up? Almost always point source pollution. If that's the problem, it can usually be addressed much more easily and efficiently than can non-point source pollution.

Dr. Arsuffi: Yes. Periodically I'm asked by various local groups and conservation organizations, to give seminars and talks about water, rivers, and streams, my research, and other topics of ecological nature.

Dr. Arsuffi: That's an EXCELLENT question. And it's a difficult question to answer, because it seems so straightforward to those of us that understand population growth and carrying capacity. We often ask ourselves, why can't other people understand? When I teach ecology, I generally go through the logistic growth equation to describe the population growth patterns that species undergo, as they go from small size to large size. And, I show them that the logistic growth equation shows an exponential phase followed by a slowing of growth until populations level off at carrying capacity. Then I describe carrying capacity as the ability of a container or habitat to provide resources to allow the population to continue to exist at that given population size. I then ask the question, last year the human population on the container Earth, reached 6 billion people, so are we below, at, or above, carrying capacity of the container Earth? A majority of students think that we are below carrying capacity. We then discuss what is evidence for or against being below, at, or above carrying capacity. That leads us to discussions of quality of life and Earth's limited resources. How do you count numbers in terms of determining carrying capacity? Is an individual living in New York City, for example, equal to an individual living in Ethiopia? And, clearly, the answer is no, that in terms of resources used, an average American consumes more than 100 times the resources of somebody in Ethiopia. So that's a factor that goes into determining carrying capacity, not just numbers of individuals. There is resource impact. People have actually done numbers of sustainable population growth of the Earth, and I ask people, here's the world that we live in now, with 6 billion people, what kind of quality of life do you want? What's the world going to be like in the next fifty to sixty years when the world population doubles? I think in terms of getting the point across that very soon now we'll be finding that water resources, locally, regionally, in the United States, and in the world -- that from the perspective of human populations, water is going to be a limiting resource. Water will largely determine carrying capacities of different regions. We're starting to see evidence right now of upcoming water wars between states. California is out of water. They want water from the mountain base of Colorado. Within Texas, there is an abundance of water in East Texas and a scarcity of water in West Texas, so how do you get that water from East Texas to West Texas? It's not going to be free -- it's going to be costly. I think in the next ten to twenty years, more and more, we're going to see conflicts arising within the U.S. and certainly within the world, and those conflicts are going to be based on need for water.

Dr. Arsuffi: I am not an aquatic toxicologist, so I cannot talk about the specific ways that chlorine and oil affect organisms in water other than to say the impacts would be very large, and probably have to do with interfering with the ability of organisms to extract oxygen from the water.

Dr. Arsuffi: It's hard to pinpoint any major achievement in terms of helping to clean up water. A while ago, I served on the Board of Directors of the San Marcos River Foundation, and we protested the city permit applications for their sewage treatment discharge, and using scientific evidence, we were able to show that at the proposed treatment levels, the discharge was having significant impact on water quality of the San Marco River. Because of our efforts, the city adopted one of the most stringent treatment plans in the state of Texas. Now, you can kayak past the sewage discharge and hardly notice that you've passed that point source of pollution. In other ways, in classes that I teach, we talk a lot about water quality, and I really believe that education and understanding of the next generation will play a very important role in terms of their own efforts and understanding of the importance of clean rivers and streams.

Dr. Arsuffi: The answer to that question is "it depends." Phosphorus in aquatic ecosystems is generally the most limiting nutrient for organisms in water. And if you recall, phosphorus is for all living life, a critical element in terms of DNA, RNA, protein, ATP, and so forth. So phosphorus is limiting. So even healthy aquatic systems need a little bit of phosphorus, so we have fisheries, and so forth. As with most things, the problem exists when we have too much phosphorus, and when we have too much phosphorus, that's when we get the wild growth and production of organisms that we don't find tasteful, aesthetic, or compatible with clean water. It's when we have lots of phosphorus that clear clean rivers and streams and lakes and ponds become choked with algae, and foul smelling because of loss of oxygen in the rivers and waters.

Dr. Arsuffi: The answer to that one is also "it depends." I think we need to be careful about separating different aquatic ecosystems, especially rivers and oceans, because they are so inextricably linked. But in terms of sheer volumes of water, rivers are clearly most in danger from water pollution. Historically, population growth centers for humans center around rivers and streams. Many of our major cities in the U.S. are located on the mouths of rivers. Many cities, from the headwater streams all the way down to the mouths of rivers where they empty into bays and estuaries, are dotted with cities and agricultural and industrial landscapes. So, primary impact would be rivers. Next would be bays and estuaries. That's where the polluted river waters first affect ocean environments. Those bays and estuaries tend to be relatively shallow compared to deep ocean water. Now, I don't mean to say that ocean waters are not polluted. Here in Texas, in the Gulf of Mexico, we have a zone in the Gulf that's called a dead zone. This is a vast expanse of water covering hundreds of square miles that is anaerobic, for various times of the year. It's believed that this is caused by a lot of nutrients that are entering the Gulf by discharge from our river systems. Now, the deep oceans, with a much larger area, and high volume of water, are probably somewhat more protected from the effects of pollution.

Dr. Arsuffi: That's a tough question. That's also a question that has answers in a whole lot of different dimension. The answer that I'm going to give you is from my own assessment of the situation. The government is trying to do something, but we're in a conflict in the U.S. now because we have people saying "we don't want the government to tell us what to do," and so there is a move to have the federal government get out of our lives. Well, then the burden passes on to the state government, and the state governments have a lousy record of enforcing environmental regulation. Part of the reason that states have difficulty is that they are close to the source and much more subject to local political pressures. The bottom line, again, is economics and money. For industries, whether it is manufacturing, agricultural, or whatever, dealing with pollution cuts into profits. So if there are environmental regulations, people can say "you are driving me out of business." Nobody wants to be not pro-business. But then, there are other users that wonder why environmental regulations are not more stringent. Again, part of the problem is dealing with a public that has different philosophies, and different short term and long term visions and understandings of environmental problems.

Dr. Arsuffi: One of the most interesting insects that I've seen in Texas? Well, when I first came to Texas, my experience in a lot of other rivers and streams were dealt with very common types of aquatic invertebrates and fish and so forth. So when I came to San Marcos, there was a whole 'nother unique set of bugs that I've encountered. I must say that when I saw my first endangered species, that was a very thrilling moment. Just to reflect on a species which has known worldwide distribution in the San Marcos River and the Comal River. Those invertebrates are the riffle beetle, and some non-insects such as a couple of the anthropods.

Dr. Arsuffi: Part of the reason why there are not uniform water quality standards across the state is because in Texas, water is classified by its uses -- what it is going to be used for. Consequently, it only has to be "cleaned up" for a designated use. Because using water for running power plants, or using water in industry doesn't require high water quality, then those standards are lower than if the water was to be used for drinking. Part of the reason that there's variable water quality standards is also the economics. It costs money to clean water. For example, sewage treatment plans have different standards by which they must clean up water to discharge to public waterways. The more stringent the standards, the greater the costs. That's part of the reason why the city of San Marcos was resistant to upgrading their plant all the way to the highest standards, because of the extra costs. But because of the high quality of the San Marcos River as it came out of the Edwards Aquifer, it was real easy to show that by not upgrading, that there was significant impairment of the river. As rivers go downstream, and are used more and more for irrigation, for industry, for personal use, and for city water supplies, water becomes more and more and more reused and degraded in quality. Once that happens, then downstream communities only have to clean the water up to the level it was before it came to their treatment plants. So that's part of the reasons why there are variable water standards throughout the state.

Dr. Arsuffi: Yes, in fact, that's the first place to start if you are interested in helping to clean up rivers and streams and getting involved -- is to find some sort of river network. Most states have some sort of water quality monitoring volunteer group. That's one place to start. Most communities have some kind of river organization that oversees the protection of rivers and streams. For example in the state of Texas, we have a statewide water quality monitoring group called TexasWatch. In San Marcos we have the San Marcos River Foundation, a conservation group that looks out for rivers and streams in the region. Down the road, we have where Comal Springs comes up in the city of New Braunfels, there is the Friends for Rivers. So, I would recommend that you would go, get on the web with a browser, type in your city name, or go to American Rivers webpage, and I think they have a list by state of environmental organizations. The thing that most people don't realize is that almost every single citizen in the U.S. is within a few miles of a headwater river or stream.

Dr. Arsuffi: If you can get involved, I think you will feel that making a difference in understanding the complexity of the problem and by being informed you will help to make better decisions. I can't think of any more exciting place to be than on a river.