TIDE: Aquascience: Lecture 1- Introduction to freshwaters and physical and chemical monitoring, automated transcript
Mar 24, 2021
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Good day, I'm Cecilia Medupin. I'm a lecturer in conservation biology at the University
of Manchester UK and I'll be presenting the talk on freshwater ecosystems.
In today's lecture, I will introduce the components of the freshwater ecosystems...
talking of lakes, ponds, rivers, streams, and then we'll look at the monitoring and
assessment....
The physical and chemical properties and the biological properties. So while I focus
on the physical and chemical aspect Professor Amanda Bamford  will present the biological
assessment of monitoring in freshwater ecosystems.
I will look at the challenges of freshwater ecosystems,
the environmental regulation and protection and that will bring us to the concluding
part of this lecture.
Freshwater ecosystems... all living organisms as we know need water and that's why
water is the medium of life.
It is made up of lakes or ponds, rivers or streams... and these are together called
surface waters. Lakes could be bigger and the ponds are smaller. The rivers are bigger
and the streams could be smaller, too.
As part of the freshwater ecosystems, We also have the groundwater.
water serves diverse purposes ...
and these include domestic which we know for drinking, for bathing, sanitation in
houses cultural purposes, for recreation, you know up there. We also have for festivals,
such as the Myanmar Water Festival, tourism,
industry, agriculture for the irrigation of farmland and aquaculture.
So globally freshwater's is made up of less than 1% in the hydrosphere. And most
of these fresh waters is locked in ice.
So we have Lakes ...
Lakes or ponds are classified as standing water.
This is because the flow is mainly absent and most of the lake waters are derived
from rainfall, surface runoff or from underground sources.
So because the flow is limited, the standing waters are called closed systems. The
systems are closed hence any material that goes in will not be able to come out
and that's why it undergoes decay and decomposition when the pollutants are discharged
in it.
It has plants, it has animals. The plants are called the phytoplankton, the smaller
plants ...and then we have the animals - zooplankton. These communities are influenced
by the materials which they receive and they are abundantly influenced by the presence
of sunlight too.
So we have periods of bright sunshine which are usually found leading to rich growth
of plants community.
And these can also influence other materials that will be found such as nutrients.
So in tropical lakes where seasonality, of course, the rainfall increases the amount
of water the lake receives.
And it also influences the productivity and the amount of phytoplankton bloom.
Now, we talked about rivers... rivers are called running waters.
This is because they move continuously in a unidirectional flow.
Running water is a very tiny percentage of global, total global freshwater. And that's
why it's very important that it needs to be protected.
So because the water is continuously moving the volume of water and other parameters
in it keeps changing.
So that means running water will influence the transfer transport and dilution of
materials and chemicals.
In addition we had the river is located the surrounding area, the catchment area,
influences the materials that will be found in running waters, such as rivers and
streams. So we now have an understanding of the differences between the standing
and running Waters.. now, let's see what's in our fresh waters. What is it that is
there?
We have categories... We have those that are more than one millimeter in size. Those
are called coarse particulate organic matter.
We have those that are less than one millimeter. These are fine particulate organic
matter and then we have those that are less than 0.45 microns. These are dissolved
organic matter.
So examples of coarse particulate organic matter... We have the large woody debris,
the leaves, the leaves, twigs, the bark fragments, the plant and animal detritus, faeces.
All of these are more than one millimeter, even the benthic macro invertebrates,
which are the organisms found at the base of rivers are more than one millimeters.
So these will be termed coarse particulate organic matter.
And then we have those that are smaller. We have the fine particulate organic matter
including microbes. And then if we look at this that are smaller even the 0.45 Micron
sized
materials... these are termed dissolved organic matter and this will include
trace metals, nutrients
from biological components.
So what do we measure?
In this lecture, we will look at the physical and chemical variables.
The physical and chemical variables
are very important as they determine the quality of freshwater ecosystems and the
biodiversity is abundance and distribution.
We measure dissolve oxygen, temperature, light, substrate and assess the riparian vegetation.
For the chemical variables we measure the conductivity, pH, suspended solids, micro
and macro elements.
The macro elements are those that are needed in higher concentrations in freshwater
ecosystems while the micro elements are those that are needed in fresh waters, but
in minute content, in minute quantities.
In the next few slides, we will briefly describe what each of these variables mean.
We have dissolve oxygen. We measure dissolve oxygen, dissolve oxygen is very important
for all aerobic organisms. All organisms that need oxygen... it can increase in streams
or rivers during the day as a result of photosynthetic activity.
And then at night they levels may decrease due to respiratory activities.
Impoundment such as dams can reduce oxygen levels and lead to an increase in carbon
dioxide.
In situations whereby we have organic pollution or low flow...
when there is like drought or high temperature conditions, like in the summer in
temperate regions, we have very low levels of oxygen. So it is important to measure
dissolve oxygen because it influences
the organisms that will be found and the situation of the freshwater ecosystem.
We measure temperature too.
All organisms,
all animals have a temperature range for which they can survive.
Temperature affects the physiological processes such as respiration, digestion, the
length of life cycles or growth.
So some animals have upper and lower tolerance limits... so that if the temperature is
above or below the tolerance level the animals will eventually die.
For example we have
fish, the salmonids fishes,
which are called 'stenothermal' fishes. They have a low range of body temperature.
This one, here, hasa temperature between 24 and 28 degrees. So the fish has
a high metabolic rate rate, a high demand for oxygen and a lethal temperature between
24 and 28 degrees. So if the temperature is less than 24 degrees or more than 28
degrees, the fish is likely to die.
Meanwhile, there are other fish species that's have the wide range of temperature
tolerance, such as the Goldfish or cod.
so temperatures
acts as a controlling factor regulating metabolism and thereby growth and this information
is very important, especially for aquaculture.
And then we measure light.
Light is needed as a component of photosynthesis. It is a major source of energy
in freshwater ecosystems. It is likely to influence plant population.
And based on the amount of energy produced by primary producers light determines
the amount of food present and the relationship determines the basis for the food
chain.
Primary producers are able to produce their own food using light as an energy source.
So in other words without light there will be no oxygen production and therefore
no food for the animals in the freshwater ecosystems.
We also measure substrate, particularly substrate and riparian vegetation, particularly
in running waters. We assess these variables in order to to determine their role
and contribution to the biodiversity of organisms and the amount of particulate
matter entering into the freshwater ecosystems.
For the substrate it provides a natural home for a variety of activities... for resting,
for movement. And when we talk about substrate, we are looking at areas,
areas that organisms can attach themselves. In some cases it could be gravel. It
could be silt. It could be Stones. It could be clay.
So it provides food, the substrate provides food directly or the surfaces by which
the organisms will live and thrive.
Should we be able to go to a river or stream during a workshop, have a look
at the some of the substrate when we collect the organisms for sampling and analysis.
For the riparian vegetation this influences the amount and nature of particulate
organic matter that is entering the streams and rivers.
Organic matter is very important because it provides an important energy source
and serves the base of the food web.
So in circumstances where by vegetation is removed in the catchment either by clear
cutting the forest,
especially on steep slopes or through overgrazing of the uplands... these can lead
to large-scale soil erosion and influx of sediments to freshwater.
We measure pH, too.
pH measure the acidity of water,
the levels of pH, the level of acidity or alkalinity, found in water depends on land
use,
soil and rock geology.
We measure conductivity,
which
provides information on the total ionic component of aquatic systems.
And the suspended solids we measure to ...
Because it informs us of particulate material suspended in water.
Usually suspended solids originated from terrestrial sources such as soil disturbance
or from runoff,
from the catchment area,  soil excavation practices, bank erosion and this can
lead to high concentrations in water.
and modifies the sediments for the organisms that live at the base of the water systems.
We measure microelements.
Micoelements, as we've said earlier, are needed a minute quantities in freshwater
ecosystems.
And these are important and have their biological roles.
In water, they can be found either as gaseous, in gaseous forms and ions or cations.
In terms of their functions, even though they are present in limited quantities,
they perform important roles.
We can see for carbon... as gas it functions in photosynthesis.
And then as anions the hydrogen carbonate or carbonate ions is responsible for the
pH
of the freshwater...
and then for oxygen is responsible for aerobic respiration and oxidation reactions.
For the trace metals is important for ionic balance in cells, calcium performs, in
addition to ionic balance in cells, is responsible for the structural component of
cell walls and exoskeleton.
The same with chloride... but chloride also has a function of osmoregulation and enzyme
activity.
For aluminium the biological function is not so apparent but we understand that
it is taken on by phytoplankton cells as ions or related ionic complexes.
We measure macro elements.
These elements include nitrogen, phosphorus and sulfur... they are needed in large concentrations
by freshwater ecosystems compared to microelements. They also have biological roles.
Similarly, they can function either as gas,
cations or anions.
Nitrogen as gas is a component of amino acid and proteins.
While for ammonia and nitrite they can break down... They can be oxidized to nitrate.
Phosphorus can form anions,  also polyphosphates, and these are components
of DNA, RNA and ATP. These are components of nucleotides, DNA, RNA and ATP.
And then for sulfur... it can form as anions and sulfate or sulfide and these
are components of amino acids cysteine and methionine.
Nutrients are important factors for plant growth and productivity in aquatic habitats
so that when we have abundance of nitrogen and phosphorus, it can influence the
nutrient status of lakes. In other words.... It's called the trophic status of lakes.
So,
in circumstances where we have high nutrient concentration in freshwater ecosystems,
this can lead to a problem or a situation called eutrophication.
So, how do we have, how do we get the nutrients into freshwater ecosystems?
This can occur from external sources.
such as
rainfall for nitrogen, aerial deposition, dust particles or fertilizer application
for phosphorus. It could be through rock weathering, human activities... example pollution
from detergents,
from fertilizer application.
It could also arise from the catchment area. If the area is largely agricultural.
We are likely to have these sources.
If it is not external, it could also be internal such as the nutrient cycling within
the freshwater ecosystems, especially in particular for nitrogen
and phosphorus which is recycled back from the sediments up to the top of the water,
especially when we have opportunities for mixing
of the water system.
The concentrations
vary by location and by seasons... and what do I mean? We are likely to find more nutrients
in the water if the lake or the river is close to an agricultural settlement.
Or from an industry that churns out these elements.
Or from a wastewater treatment works that does not sufficiently treat phosphorus.
And then during rainy season the concentration of nutrient could be diluted.
So at that period you are likely to find the concentrations in the river or streams
lower because of the Continuous flow.
And now, having an understanding of what is in our freshwater's, particularly the
physical and chemical variables....
It is important to know why we need to protect our fresh waters.
The objective
of the United Nations sustainable
development goal 6
wants
to ensure clean water and sanitation.
In unpacking clean water and sanitation.... This means there is a need for accessible
water,
safe water, and
it needs to be effectively managed to ensure environmental sustainability and economic
prosperity.
This imply that the quality of water is as important as the quantity of water in
order to ensure sustainability.
and remember ...
freshwater ecosystem is less than 1% in the hydrosphere. So by all means there is
a need for this resource to be protected
for environmental sustainability.
So talking about quality. We need to protect our water from pollution.
Such as eutrophication, acidification and all forms of contamination.
Because we need the water for our diverse uses.
In terms of quantity, there is a need to regulate the amount of water abstracted
for industrial use or for any other forms of use. Why should it be so?
Globally, as example 2018 United Nations population statistics, there are seven point
six billion people.
And in Myanmar, we have 15 million people who need water resources.
In Myanmar we have the main source of water from reservoirs and rivers with limited
use of groundwater.
Get the full information about the water quantity in Myanmar.
...approximately 90% of rainfall happens between May and October.
And there is more rainfall in the Delta Region compared to the central dry region,
at least we understand from the Integrated Water Resources report, that the Delta
Region receives approximately 5,000 millimeters of water compared to the central
dry region, which receives less than 800 millimeters of water and in 2000 the total
water withdrawal from surface and groundwater was more than 33 million cubic meters
per year.
And out of these 89 percent was used for irrigation and livestock.
10% was used in the municipalities and 1% for Industries while we have 2.8 percent
for each inhabitant for their domestic use. So
overall what we have is that
out of 89% we have 11% that is needed for domestic and industrial activities.
Should we be concerned?
Possibly. Yes.
Because there are local water shortages.
There are also potential projects that require water.
And these projects will impact the level of usage of the project of water and those
projects will impact on water quality and quantity.
So in other words water quality and sanitation could be compromised as a result
of limited water resources... and we have development projects.
Increased hydroelectric power currently in Myanmar we have about 40 hydroelectric
power plants in operation.
and 89 planned ...
as this hydroelectric power plants are being proposed.
It means there will be a lot of constructions for dams.
What are the implication for these activities? It means there is going to be increased
water abstraction.
In some places there is going to be
straightening of river channels... to increase transportation and navigation.
This is likely to impact on the hydromorphology of the river systems.
Other we have mining activities, which are likely to lead to run off from spoil hips
and chemicals are also used for the separation of target minerals.
and then some areas would need to be,
to undergo deforestation.
And deforestation, of course, we know we need to run off of materials during rainy
season into freshwater ecosystems.
And then when we have increased agricultural activities. We are likely to have run off
of fertilizers to freshwater ecosystems.
So what are the implications for water quality from the projects and their pressures?
We are likely to have reduced water quantity,
impact on freshwater biodiversity.
We are likely to find heavy metal contamination from mining, such as arsenic...
Acid mine drainage from mineral extraction,
erosion and sedimentation from logging activities from all activities of deforestation
And from agricultural, from the intensity of agriculture, we could have nutrient enrichment
in lakes.
and then
from dam construction. There are likely to be impacts upstream and downstream. From
the upstream, upstream sites. We have deposit of fine sediments on to the original
substrate.
reduction of flow behind the dam.
and then downstream we have release of huge volumes of water from the dam.
And high sediment concentration will be generated downstream. These deposits.
and the release of huge volumes of water
will impact on the physical, chemical and biological properties of our water.
So what do we do? How do we protect our fresh waters?
It is important that we look at our fresh waters
as collective management!
How can they start, how do we start looking at it? We have environmental regulation
and enforcement... that means
we need to start looking at standards that will help in the regulation of our water.
Which standard should we be looking at in order to ensure that companies, industries
businesses comply... to ensure that concentrations released into freshwater ecosystems
are
controlled and maintained.
It is also important that we have regulations that inform people on what should
be abstracted from waters the quantity that should be abstracted, part industrial
activity.
Well, we are looking at the environmental regulation and enforcement. It is also
important to know
which activity should be classified as 'Major Impact' that needs
some licensing from the environmental regulators.
And while we are looking at regulation compliance and guidelines from the environmental
regulation from the environmental regulators.... it is also important that the standards
are enforced by environmental institutions, and that means non-compliance could
lead to
penalties
to those who breach the regulations.
It also implies that different environmental institutions will work together to
determine what they regulate and how these will be communicated to users.
It is also important that our freshwater ecosystems are monitored and assessed.
for physical, chemical and biological variables.
At the moment in Myanmar, we have heard of the 'National Water framework directive',
as a National Standard.
This is based on the 'European Union's water framework directive' and it helps in
the protection of European Union surface waters and ground waters.
The broad aims of the European Union's water framework directive which is also based
on the standard being employed in Myanmar... is to achieve good ecologically status
for the European, you know, the target is 2021....good ecologically status for
all surface waters by 2021 ...to prevent deterioration and to ensure the conservation
of high water quality where possible.
So their main focus is to assess the status of the biological component,
the physical and chemical elements will also be assessed as supporting elements
for the biological status.
And to determine their impact on rivers and lakes.
And then we have the hydromorphological element, which is also is supporting quality
element which describes water flow conditions and water levels.
So ALL parts of the physical, of the chemical and biological components have to be
GOOD for the water body to comply with the EU water framework directive,
the local National Water framework directive before it can be classified as good
as ecological status.
What does this mean for us?
What it means is that we need in order to be able to classify our freshwater ecosystems.
We need to know what is there in other words...we need to know
what we are monitoring.
Which regulations we are complying to?
And we need continuous data and that's why I recommend that we establish a collaboration
between research institutes, academics and government officials in environmental
monitoring.
On the assessment of water quality, we need effective data collection and storage
because that would help us to determine what the situation is at present and possibly
simulate what the problem could be in the future... and then that would inform policy
changes or policy amendments.
AND we need effective water regulation and protection.
Communication and participation through media workshops educating people
and then cooperation between governments, states and divisional governments.
When this happens, this kind of relationship happens, it means that even our research
and the way we look at water freshwater ecosystems. We not be one-sided. It would
be a holistic form of management.
In conclusion, we have learnt about freshwater ecosystems.
Some challenges to freshwater ecosystems.
The need to regulate our waters.
And the institutions.
We also have learned about monitoring, and assessment in particular
physical chemical variables.
And you will learn about biological parameters.
Thank you!