A Study in Stream Ecology

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Detailed Description

In this episode we explore how scientists for the USGS National Water Quality Assessment Program investigate the ecological health of rivers and streams across the United States. Focusing on a recent sampling effort along the Minam River in northeast Oregon, this video highlights USGS sampling methods for fish, macroinvertebrates (bugs), algae, and habitat. Join us, as we show biometric data can be used to assess the health of streams, only in this episode of the USGS CoreCast.


Episode Number: 168

Date Taken:

Location Taken: US


A Study in Stream Ecology

[Intro Music begins]

[Steven Sobieszczyk] Each year USGS scientists systematically 

assess the ecological health and water-quality conditions in 

streams and rivers across the United States. This research 

plays a vital role in land management and natural 

resource decisions around the country. Contrary to 

popular belief, these extensive data collection efforts

 completed by researchers in the USGS National 

Water-Quality Assessment Program involve much 

more than just water quality.

[Kurt Carpenter] Back when the NAWQA program 

first started, the National Water-Quality Assessment

Program, they recognized the need to incorporate biology 

into the sampling. We look at the algae thatís in the different 

streams and rivers and the bugs that eat the algae and then 

also the fish that rely upon the bugs as a food source. 

We also look at the habitat and the water quality 

to see how all these different groups of organisms 

respond to things like nutrients, pesticides,

temperature, and other stressors.

[Ian Waite] What weíve done is weíve developed 

these methods that seem to work well across the nation. 

We have standard methods and standard protocols 

and so that way when we do the sampling hereÖ

and the same methods are used back in the east 

coast or the Midwest or whatever, that weíve 

sampled everything in the same way. So we can

 compare and combine the data sets and 

actually assess things nationally or regionally.

[Kurt Carpenter] The program, in general, is 

looking at watersheds across the nation in 

pretty large river basins. And that has provided 

hundreds and hundreds of sampling locations

in areas of urbanization, agricultural land uses, 

but also in settings like thisÖforested ecosystems 

that havenít been as impacted by anthropogenic activities.

[Ian Waite] One of the things thatís really 

important in what we call ìbiologic assessmentsî 

of streams, so how do weÖcan we understand the 

conditions of streams and make a comparison

between one stream and the next isÖyou have to 

know what is your reference, or minimally 

impacted condition.  If you donít know what your 

benchmark is, you canít then say when are things 

impacted or impaired or how or when are things 

changing. With climate change? Or with land 

use changes? You need to know your benchmark.

[Ian Waite] All the different ecological data, the 

algae, the macroinvertebrates, the fish, they give

us different indications of whatís happening. One of 

the things weíre realizing is that itís important to 

study more than one type of biological organism in 

the stream. Because each one can give you a slightly 

different signal. The other thing that it really gives 

us an indication ofÖis land use affects. Or when 

we look at the affects of agricultural land use on 

streams that we see that the biological is a really 

good response indicator of impacts due to water 

quality, or habitat changes, or sedimentation, or things like that. 

[Kurt Carpenter] When we start to see impacts

from things like water pollution on the biota, 

we see that in a variety of indicator species, a 

lot of the time weíll see the diversity decline. 

Instead of having a food web where nutrients 

and light energy combine to produce a real 

productive stream that we tend to see as having 

a healthy trout population, or at least in these 

mountainous streams in the west. What you 

find is that you donít see very many trout 

and the benthic vertebrate population is greatly 

simplified, you donít see a lot of mayflies 

and stoneflies or other types of food for the fish. 

That can ultimately be traced back to water pollution. 

[Ian Waite] Water quality is important to sample 

but one of the problems is it is expensive and 

it is only a one-time sample. It only grabs the 

water and gives you an assessment of what is 

happening at that one time. Where the biology, 

they live there all year long. So what you find 

when youíre sampling is theyíve been living 

and have been exposed to all the conditions 

that have happened all year long. And thatís 

why biology is a really good indicator of the whole system. 

[Kurt Carpenter] A lot of the management and 

policy decisions that are set are driven by

bio-criteria. And so we look at the health of 

biologic communities, really the full assemblage 

of fish, bugs, and the algae to get a full assessment 

of what the biota look like. But then we also 

collect samples and analyze water samples for 

nutrients and pesticides. Through the monitoring 

that we do and these interdisciplinary studies, 

and multidisciplinary approaches, we use all kinds 

of different modeling, and multivariate statistics 

and tease all this stuff apart, but ultimately we hope 

that the information we generate can be used by 

management agencies that dictate things like 

nutrient levels that are permitted in streams and 

controlling runoff and erosion and all those sort 

of processes. And really, without this kind of 

information where do you really begin.

[Steven Sobieszczyk] To find out more about NAWQA 

sampling efforts in your area or to learn more about how 

the USGS monitors the ecological health of rivers in the 

United States, please visit the USGS online. Historical 

data from Oregon, as well as the rest of the country can 

be found at our National Water Information 

System or at our biodata websites.   

This has been a video production of the Oregon 

Science Podcast, U.S. Geological Survey, Department of the Interior.

[Outro Music ends]