TIDE:  Aquascience: Lecture 2 - Biological monitoring to assess health of freshwater systems, automated transcript
Mar 25, 2021
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Hello, my name is Professor Amanda Bamford. I'm a professor of plant Sciences at
the University of Manchester in the United Kingdom. And I have interests in air
and water pollution. Today, I'm going to talk to you about biological monitoring
of freshwater systems.
My lecture today is going to be all about using organisms to measure the health
of rivers and lakes.
So the outline of my talk... is I'm going to start off with the introduction. We can
briefly consider by monitoring and bioindicators and talk about what they are. And
also why we actually monitor the organisms that I'm going to show you today. I'm
then going to move on to talk about river biomonitoring and how we can use benthic
macro invertebrates to monitor the health of our rivers and I'll explain all these terms to you
later in my lecture.
We're then going to move on to lake biomonitoring.
We're going to be using algae and zooplankton to monitor the health of lakes, and
I'm going to talk to you about how they're useful for doing this.
So lets start!
Firstly, what are we talking about when we're talking about monitoring, biomonitoring
of freshwater's? Well, biomonitoring is generally defined as a method of observing
the impact of external factors on ecosystems and their development over a period
of time... or if determining the differences between one location and another for example
a clean area, a clean lake and
another Lake where you think there might have been a pollution incident. So by monitoring
can be very useful for comparing two different places.
So you can biomonitor species or communities by characterizing their richness.
So that's how many species you find ...and the composition, that means about
the type of species or taxa that you find in your system. And this type of biomonitoring
has been identified as a very sensitive tool for looking at health of fresh waters.
It's very quick and accurate. It can detect changes in aquatic systems very efficiently.
So healthy ecosystems can be considered the same as good water resources...its very important
that we have healthy ecosystems in our waters.
and the EU water framework directive
is based on the principle that healthy ecosystems are the basis for sustainable
water resources. So one depends on the other!
Since 2014 the National Water Resources Committee in Myanmar of adopted the National
Water framework directive the NWFD.
And I'm sure that Cecilia has already talked to you about these in the previous
podcast.
So the EU water framework directive has a number of different elements to it.
They measure five different parameters.
They measure
phytoplankton,
which are microscopic organisms that contain chlorophyll... aquatic macrophytes which
are plants growing in or near the water.
Thirdly, phytobenthos
which are algae living on the bottom of a river (benthos means bottom).
Number 4, benthic macro invertebrates, which are animals living on the bottom of rivers
and number 5 fish. So all these are excellent indicators for ecological status
because they can respond to a variety of different impacts. For example, nutrients
light, temperature, heavy metals, herbicides, turbidity and water
level change.
So all these five are routinely measured, for example by the Environment
Agency in the UK.
So we're talking about bioindicators of water quality.
What's the definition of a bioindicator?.. Well it's a organism, or a community of
organism indeed, that give information on the quality of the environment. And here
we have a picture of a diatom on the left and a macro invertebrate on the right.
So examples of bioindicators.
So these biondicators can be used to buy a biomonitor your system.
In a well-studied ecosystem, the changes in the numbers of organism and types can
give very accurate information about pollutants and other stresses from the environment.
And across the world this type of methodology is used routinely.
Biological assessment and monitoring of aquatic resources have been measured and
used in many parts of the world. For example, Europe, Australia, United States and
indeed my home country of United Kingdom.
Many countries or states or water authorities have indeed  developed their
own biotic indices that reflect the systems in their countries.
One of the references that I've given you the end of these slides is Li, Zheng and
Louis (2010) that give you much more information about all the different assessment
and monitoring systems that go on.
So why do we measure these organisms?
If the number of the species or in other words the richness and abundance change
over time, it might indicate effects of human activity on the stream or lake.
So you can keep biomonitoring every month or every year and look for changes in
your ecosystem ...and such biological monitoring is based on the fact that different
species react to pollution in different ways. So this is the CRUCIAL thing to remember!
That the whole of biomonitoring is based on this.. your different species
react to pollution in different ways.
So why do we survey? Well one type of survey is surveillance, so you can look at
before and after a particular project, a building project or building a dam, or installation
of a sewage system ,so you can survey the different impacts of your activity before
and after.
The other reason for surveying is for compliance. So by routinely, regularly
sampling of toxicity testing. You can ensure compliance with mandatory standards.
So you can check that your system, your river or stream or lake, is meeting the legislative
requirements for your country.
So let's start off by talking about river biomonitoring.
So here's some of my students out in the cold in the UK with their waders on taking
different measurements of our rivers.
The ones on the right are doing kick sampling, which is a way of collecting benthic
invertebrates from the bottom of rivers. And this is one of the things that you'll
be doing or watching doing in our face-to-face activities in Myanmar.
So in order to do about social assessment....
It's a three-step process.
Firstly you need to sample the aquatics organisms, obviously like these two girls
on the right using a kick net,
and then you summarize the data using biological indices and I'm going to show you
some of these later... and then finally you compared to your reference streams or previous
data or previous published information, to see whether there's been any changes or
significant impacts.
So this is quite a complicated river with a food web. So don't really have to worry too
much about it! But what I want to show you on here is that in any freshwater system,
you have a pelagic pathway, which is the area where free-living, free-swimming organisms
are found... like fish.
And then you have the benthic pathway, which is the organisms that are living on
the rocks or the bottom of the river or on the sides of the lake or even on the
plants around the lake. So benthic you see the ones that are attached and not free
swimming around, they tend to be found on the bottom of the system you're looking
at.
So all these organisms in this diagram a potential bioindicators.
But obviously it's no point measuring everything! We haven't got the time and so
one of the first things and most common things that people do look at
Are these types of organisms which are macroinvertebrates.
So now I'm going to talk about using benthic macroinvertebrates as bioindicators.
Benthic macroinvertebrates are organisms that inhabit the bottom substrates for at
least part of their life cycle, as nymphs very often, and are retained by 200 Micron
to 500 Micron mesh.
So very particular size of organism.
And you have two pictures at the bottom of this slide showing you two common benthic
macroinvertebrates.
These macroinvertebrates are key components of a food web.
And they link organic matter because a lot of them eat the organic matter and are actually
nutrient resources for other organisms in the food web.
These macroinvertebrates are affected by the physical, chemical and biological
conditions of the stream to different levels. So different organisms will be affected
differently. As I said earlier, which is an important characteristic of a bioindicator.
Some are very vulnerable and very sensitive pollution. For example, this caseless
caddisfly shown at the bottom of the slide on the right. While others can live and
proliferate in disturbed and really very polluted waters very happily.
So taken together the presence or absence of tolerant and intolerant types provides
an insight into the water bodies overall health.
00Ff we're looking at macroinvertebrates, we have to identify them.
And this slide is reminding you or showing you of the taxonomic sequence where animals
are classified.
We have the kingdom down to the species.
So if the kingdom, for example, you've got Animalia.
And then to phylum for example arthropoda, class insecta.
Order Plecoptera, family Capniidae and genus Capnia and species vernal.
Very often most of us don't have the experience and the expertise to identify something
down to species level. Some of these organisms are very, very difficult to identify.
Luckily most times, you only have to identify it down to order and family. And
in fact in our lab exercise will mostly only go down to order.
So what we'll do is you take your sample, you go out into the river do your kick
sample of benthic invertebrates, bring them back to the lab and identify them down
to major taxa for example order.
And then you look at whether the organisms you found a sensitive or tolerant
to pollution. So here's some examples of some pollution sensitive taxa. We have
stonefly, order Plecoptera (picture at the top)... mayfly nymphs order Ephemeroptera
... here with three tails.
And Free Living caddisfly larvae order Tricoptera...  which have an example of a picture
here the bottom. So if you see in your sample lots of these particular taxa, then
you know, it gives you an indication, that your water quality is quite good.
Because if it was polluted you really wouldn't see these these taxa, these orders at
all.
So it gives you a good indication of the quality of your water.
Some other taxes that are more sensitive, for example case caddisfly larvae, Order
Tricoptera... freshwater shrimps order Amphipoda... and beetle larvae order Coleoptera
, which is these this example at the bottom right of the slide.
So these are called  somewhat sensitive taxa. Some of them like the freshwater
shrimps can actually find in quite polluted waters, but they also found in clean
waters.
And then another group will be your pollution tolerant taxa. Now these, if you find
a lot of these taxa, you know that your water is probably polluted. Obviously, we
don't know by what at this stage, but just the presence of these organisms are
a good indication that your water quality is not very good. So you have things like
Midge larvae order Diptera.
Family Chiromonidae, this these ones here. Black fly larvae order Diptera and
leeches order Hirudinae. So if you see a lot of leeches in your water, you
know, the water quality is very poor!
So you hopefully by now you're getting the idea of how you can use organisms as
bioindicators.
So not just by looking at the species or the taxa that are there, you can actually
do some calculations of metrics to help you analyze your system and there's lots
and lots and lots of these.
Some more popular in for example the US, some of our more popular in Europe and some
are more popular in Asia. I've listed here some of the most common ones.
We have the biological monitoring work in party score. In other words the BMWP.
This was developed in the UK and it is used extensively in UK and in fact around the
world... and this system allocates different taxa a scoring according to how polluted
the organism can stand in the system. So for example,
something very sensitive to pollution will get a score of 10 and something that's
very tolerant pollution might get a score of 1.
We're actually going to look at this BMWP and try it for ourselves in the lab.
The other metric you can look at is total number of taxa. So the total number of
species or genus, or order that you find... so that's richness.
The other thing you could do is look at the number of Ephemeroptera, Plecoptera and Tricoptera
taxa that are present in your sample. And these are the ones that are
very sensitive to pollution. So if you have a lot of these then you know that you've
got quite a good quality water. The other one you can look at the % of the mayfly
which is the Ephemeroptera and look at that as a total number of your taxa... what
percentage
are mayflies? So the number different metrics you can use.
So for example some of the changes in invertebrates show when there's been an impact.
Nutrient enrichment... if you have nutrient enrichment very often you see an increase
in the ratio of aquatic worms to aquatic insects. So that might be something very
straightforward that you could look at. Another metric you could look at was increased
ratio of midges.
In other words chironomids to other aquatic insects.
Low dissolved oxygen... if you have that and system with very low oxygen levels,
you might see an increased ratio of aquatic worms to aquatic insects.
Contamination by heavy metals... you might see an increase ratio of midges to other
aquatic insects.
I'm finally low pH...you might see a loss of snails, daphnids, mayflies and midges
in a system with low pH. And in fact in our workshop, we're going to be looking at
pH and we're gonna be looking at nutrient enrichment to see what impact that has
on the benthic invertebrates.
What the advantages of macroinvertebrates? Well there are lots of advantages of using macro
invertebrates to buy monitor your system. They're found worldwide. I'm sure I'll
see invertebrates that I see in the UK, I'm sure we'll see some of them in Myanmar.
So they found in habitats all around the world and they're very, very similar around
the world.
They're found in areas that might not have fish. So again, that would be very useful
because if you don't have any fish in your system, there's no point using fish
as your bioindicator.  There's a large number of groups. So as I said in the
previous slide, you can look for a wide spectrum of responses and they can tell
you a lot about what's happening in the system. They're sedentary, they're not swimming
around, they tend to stay in one part of your river system. So
you can keep going back to the same area again and again, maybe throughout the
year, over years and look for changes.
Their life cycle is long enough to see changes but quick enough to detect problems
fast ....the advantage of using bioindicators like this is that ...if you try to use chemistry
methods
to detect a pollution incidents, for example. That pollution incident might have
happened a few weeks ago or a month ago. And now the river quality, in terms of that
particular say heavy metal, is now gone... heavy metals disappeared... but it had an incident
a few weeks ago that was quite detrimental. If you just use chemistry methods you
might miss that but the macroinvertebrates have been sitting there and they've
experienced, for example that heavy metal impact, and you'll be able to come along a
few weeks later and see that impact... maybe some of the species have now disappeared,
maybe a lot of them are dead. So you can pick up changes that might have happened
a while ago, but also they react very quickly. So say an incident happened the day
before, you can go to the following day and you probably see impacts already happening
on the organisms that you find in that system.
The sampling analysis is relatively inexpensive. You don't need lots of very complicated
equipment.
And the taxonomy of the many groups are well in known, there's lots of keys out there
to help you identify, some online,  some really good ones online. There's lots
of books to help you identify the different groups. There's lots of methods, data
analysis. There's lots of lots of literature around using this method of
biomonitoring and the response of very common species is well-known. So you could look
up the species that you're finding and finding
their responses to different pollution impacts
However, there's some disadvantages... under natural conditions currents and substrates
some of those might still affect the distribution and abundance.
It might be a natural change that's happened, not on human modified change.
This is seasonal variations in diversity anyway. Natural variations in life cycles
and food webs and so these can create problems if you're not aware of them.
And that is obviously pollution might not always be the one responsible for the
absence. Maybe it's just not found that time of year. Maybe something's happened
to the habitat that's nothing to do with pollution at all.
Sample processing, identification can be costly. If you have to get somebody
else to do it or pay someone else to do it get an expert in... and it can be difficult
identifying the the species. I'm sure as I'm sure we'll find out! And can be
very time-consuming as well if you have lots and lots of organisms in your
sample.
So this is a case study published in 2007... looking at the shifting community composition
related to human water withdrawals along a river in Oregon, United States. So
this is to give you an example of how this type of by monitoring of benthic organisms
can work.
On this graph... We have relative abundance on the left hand. We have water withdrawal
going along the bottom axis and the line is the amount of water that's discharged
from the river.
So first of all, you can see amount of water extraction
from this river
means that by the end of the system, end of the time.
There's very little water left in the river.
So the water withdrawal will have a major impact on the community living in that
river. So the green bar....
the bars along here... the green bars represent the disturbance-intolerant insect
taxa.
That we were talking about before for example, the Ephemeroptera, that are very
sensitive to any disturbance to any pollutants. And you can see here that as the
water is extracted, the relative abundance of these disturbance-intolerant, these pollution
sensitive species, drops dramatically.
However in contrast if you look at the blue columns, which represent the adapted
non insect
organisms, for example leeches, these increase as the water levels drop in the
river.
So you can look at community changes
very, very quickly by monitoring the composition of the species found in your river.
So let's move on now to lake biomonitoring.
Here we have pictures of some diatoms.
And we have one of my students with the net, with the phytoplankton net, which is
the net you use
very often to collect algae in lakes.
So there's a lot of pressures on freshwater lakes.
(As Cecilia discussed in her earlier podcast)
These main pressures include excess nutrients
And organic pollutions that can lead to eutrophication. You can see here in this
picture on the right. And pesticides and herbicides run off all that can impact on
our lake systems.
So instead of using macroinvertebrates, in lakes we can use algae, phytoplankton
as our bioindicator.
These are microscopic organisms
and they contain chlorophyll and require sunlight in order to grow and live. And
they are primary producers in our Lake food web.
And here we have some examples of some algae that you find commonly in lakes.
Phytoplankton have very short life cycles and rapid reproduction. So that means
that they're react very sensitively against any changes, especially nitrogen and
phosphorus.
One thing to look out for, when you're doing your lake sampling, is a sign of bacterial
blooms.
There are naturally occurring cyanobacteria (or blue-green algae) and they can quickly
multiply, multiply and form dense mats. Just covering the whole surface of your Lake.
And they most commonly occur the high temperatures with high nutrients in
the water.
And worryingly some of these bacteria produce cyanotoxins and each genera
can produce multiple types of cyanotoxins.
So if you are doing a lake monitoring system, obviously cyanobacteria are one of
the key organisms that you're going to look out for.
At the bottom of this slide, you can see a picture of Lake Erie and you can see
all this bluey greeny Colour, which is the Microcystis bloom, which is a very common
cyanobacteria.
The bloom is like a greenish, thick paint like material here. You can see here on
the slide at the bottom. Another common sign of cyanobacterial bloom is caused by Anabaena.
And this bloom tends to occur in the summer and it's slimy and you can see it as
large dark dots in the water samples when the levels get really really high.
The third type of cyanobacterial bloom is caused by Planktothrix,
and Oscillaroria. And this is filamentous bacteria that calls horrible, strong, earthy
color, earthy smell in the lake with dense surface scums on the top. So when the
levels of these cyanobacteria get really high you get these blooms.
And this is what they look like under the microscope.
Here we have Anabaena on the top left.
Microcystis and Planktothrix or Oscillatoria.
So we'll be looking at for these when we do our Lake analysis. But even if you have
just a few of these phytoplankton in your sample, it's not yet a bloom, just the
very presence of them will give you cause for concern because you don't know that
maybe later on in the year, or when there's a sudden influx of nutrients, maybe from
a fertilizer, that these cyanabacteria
multiply rapidly, produce sign of toxins and give you a real problem in your
Lake.
They can cause lots of human symptoms, indigestio,n vomiting, diarrhea, abdominal pain,
headaches.
So these different algal toxins.... There's a whole range of them here as you can see
in the table on the left from microsystems,
produced by Microcystis, nodularin and produced by Nodularia
And some of them can produce more than one algal toxin. So these are not things
that who want to build up in your Lake!
The World Health Organization has a recreational water guidance and action level
for cyanobacteria and cyanotoxins. So  some of these are things that are
very routinely monitored worldwide. So you have low levels of these cells you have
low probability of acute health, but if you count numbers of your cells and they're
above 10 million per mil, which they can reach, the probability of actually acute
health effects
is very high. So what do you routinely do in your monitoring is count the number
set cyanobacterial cells in your sample. And if you count your number of cells,
you can estimate the levels of your cyanotoxin in the sample.
There's also drinking water levels...
And again, these are routinely monitored the amount of microcystins in the water
and drinking water, is needs to be monitored. Especially not areas where you've got
algal blooms. You don't want your sign of bacteria levels to be very high.
So that's phytoplankton. So we've now covered macroinvertebrates in your rivers,
in your Lakes you can use
phytoplankton and you need to look out for cyanobacteria.
You can also look at zooplankton as your Lake bioindicator for health. Now, these
are my new aquatic animals that are non motile,
very weak swimmers. They can move around a bit and they drift in the water. That's
what plankton means means drifters.
Very important element of the food chain because a lot of fish eat these zooplankton,
they form fish pray.
And the zooplankton community is composed of highly sensitive organisms that responds
to a large number of environmental changes in a relatively short period of time  ...
you can even be  hours.
So let's have a look at the major zooplankton that we could actually monitor.
Firstly, there's cladocerans or we call them in England water fleas. You see find
them in standing water, ponds, lakes anywhere like that... and they're important food
for fish.
They feed on smaller zooplankton, some species feed on algae and they're very highly
responsive to pollutants.
Second group is called rotifers.
And these are soft-bodied invertebrates with a very short life cycle and they float
around in your water body.
And under favorable conditions, you can get very high quantities of these, very quickly.
So they're very responsive.
Finally, there's copepods... these are organisms with a tough outer skeleton and they can
swim really fast through the water. And they can be very tolerant toward a wide range
of pollutants.
And there are two major groups of these. There's cyclopoids and calanoids and
very easy to tell apart by the size of their antennae.
And because their tolerance of a wide range of pollutants, looking for these in
the in your Lake sample can tell you a lot about your water quality.
So sort of metrics you can use for zooplankton... if you see a lot of zooplankton
this is been related to rise in levels of eutrophication. Lots of
nitrates and phosphates.
And the ratio between the two different types of copepods has also been associated
with disturbance levels, often nutrients into rivers as well. So you can look at
the ratio between these two different organisms to give you a number to assess your
your Lake compared to another Lake for example.
So we have seen three different bioindicators classes... macroinvertebrates. phytoplankton
and zooplankton. So how can choose which one do you do, do all of them? Do you have
enough time? Well, the ideal indicator should be easy to measure and interpret, be
sensitive to that before any severe damage to the whole system takes place. So you
want to pick up any major changes
with these bioindicators before the whole system is affected and maybe all your
fish for example start dying or it affects human populations.
You want your bioindicator to be
sensitive to a range of stresses and levels not just one pollutant.
Applicable across water types, different types of systems.
Ideally distinguish between natural variation and human disturbance and contribute
to the diagnosis of the impact or change. So it will give you a diagnostic level
along with all your nutrient chemistry, pH, oxygen levels. This is an added indicator
for your water quality, on your ecosystem quality.
I've given you here is some very important resources and references that you can
go and look up ...especially the one at the bottom ...which really talks about water quality
criteria for lakes and rivers in Myanmar. It's a preliminary report only been published
in 2017, but it's really useful reading because it will go through a lot of the
things I've been talking about.
So that's the end of this lecture.. lecture 2.. in this series of Aquasciene lectures.
So thank you for listening. So now, you know all about how you can use biological
specimens for monitoring your freshwater systems and the health of rivers and lakes.
Thank you!