1. Water Quality and Macroinvertebrates

2. Too Much of A Good Thing
Humans activity and occasionally wild animals can increase available nitrogen and phosphorus in water bodies, with dramatic consequences for aquatic ecosystems
When these inputs occur, high levels of nutrients are considered pollutants, like heavy metals or acid precipitation
Other physical factors, such as temperature, and suspended solids (turbidity) also have significant impacts

3. Nutrients and Pollutants
Water quality is largely a function of the concentration of dissolved substances in the water
In most ecosystems, nutrients such as phosphate and nitrate have limited availability; healthy environments are oligiotrophic

4. Point Source Pollution
Point source pollution is pollution that comes from a single source, such as a factory or a utility. Modern poultry and livestock operations contain thousands to millions of animals, and can be considered point sources. Because of intensive regulation, the Catskill Park has few significant point sources of pollution.

5. Non-Point Source Pollution
Non-point source pollution does not have one specific source.
Agriculture is a major non-point source of nitrates and phosphates
Non-point source pollution comes from the cumulative effect of a region's residents going about their everyday activities, such as fertilizing a lawn, washing clothes, or flushing a toilet
Non-point source pollution is much more difficult to pinpoint and control

6. Consequences of Enhanced Nutrient Levels
Enhanced levels of nitrate and phosphate invariably result in algal blooms
When phytoplankton die off, they fall to the bottom of the water body, increasing turbidity, and reducing the amount of light that penetrates the water
Decomposers consume the dead algae, dramatically reducing dissolved oxygen levels in the process, resulting in “dead zones”

7. Eutrophication

8. Macroinvertebrates and Water Quality
Aquatic macroinvertebrates vary in their sensitivity to enhanced nutrient levels
The presence or absence of certain species is an excellent indicator of the health of a water body
Surveys of macroinvertebrates can be used in addition to or in place of direct chemical methods for measuring water quality.

9. Macoinvertebrates and Water Quality
Macroinvertebrates are rated on a 1-4 scale based on their sensitivity to high nutrient/low dissolved O2 levels
Most sensitive 4 points
Somewhat sensitive 3 points
Tolerant 2 points
Extremely tolerant 1 point

10. A weighted average can be used to determine a water body’s “GPA”

11. Types of Macroinvertebrates
We will look at some common macroinvertebrates, classified into four groups based on their sensitivity to pollutants
There are multiple species of each type of macroinvertebrate, which usually require extensive evaluation
Our class project involved looking at macroinvertebrate populations in a small pond at the Ashokan Center in October.

12. GROUP 1 MACROINVERTEBRATES
They are all intolerant to pollution, require high dissolved oxygen contents and like cold water

13. Stonefly Larvae 3500 species worldwide and counting
Found everywhere except for Antarctica
Intolerant to water pollution
Require high dissolved oxygen concentrations

14. Dobsonfly Larvae Over 220 species worldwide
Found in the Americas, Asia, and South Africa
Reach lengths of up to 5 inches
Intolerant to pollution

15. Alderfly Larvae Approximately 66 species Intolerant to pollution
Less than 1 inch long
Needs high dissolved oxygen concentrations

16. Water Snipe Fly Larvae Grow up to ½ inch Intolerant to pollution
Found around bushes shrubs and tall grasses
Will only inhabit the bottoms of very clean flowing water bodies

17. Benthic Macro-invertebrates Semi-Sensitive to Pollution
Group Two
Benthic Macro-invertebrates
Semi-Sensitive to Pollution

18. Caddisfly Larva
Caddisflies represent a large range of pollution tolerance.
The larvae feed on algae, small bits of plant material and animals.
Some caddisflies build a net or house-like structure in which they catch drifting food.
They are fed upon by several species of fish.

19. Dragonfly Larva
Dragonflies are found in slower moving streams and ponds.
They often reflect waters with lower dissolved oxygen levels.
They feed on other aquatic macro-invertebrates, tadpoles and small fish.
Eggs are deposited on the surface of the water and drift to the bottom.

20. Water Penny
Water penny beetles indicate an ample supply of oxygen and fast flow of water.
They primarily eat plant debris such as algae and diatoms
They are not truly aquatic; they can be found on emergent rocks in riffles.
The adult female water penny deposits her eggs on the underside of stones.

21. Crawfish
Crawfish indicate moderately clean water; they are seldom found in polluted waters.
They are omnivores.
They are preyed upon by larger game fish.
Females carry their eggs in a large mass underneath their tail that resembles a raspberry.

22. Crane Fly Larva
Crane flies indicate moderately clean water; they are seldom found in polluted waters.
They feed upon mostly plants and plant debris.
They are worm-like.
Females deposit eggs on submerged vegetation or other debris.

23. Freshwater Mussels and Clams
Mussels are sensitive to situation and low dissolved oxygen.
Clams can be found in degraded conditions.
They are primarily filter feeders for organic debris and plankton.
They are preyed upon by numerous fish and mammals.

24. Mayfly
Mayflies display a varied tolerance to pollution, but are generally considered cleaner water benthos.
They feed upon small plants and animal debris.
They are preyed upon by fish.
Females deposit eggs on the surface and they then drift to the bottom.

25. Damselfly
Damselflies inhabit slower moving waters, margins of streams, ponds and lakes.
Their indication of pollution in water varies.
They feed upon other aquatic macro-invertebrates.
Females deposit eggs on the surface of water where they drift to the bottom.

26. Riffle Beetle Riffles beetles are found in fast moving waters.
They indicate an ample supply of oxygen.
They primarily feed upon plant materials such as diatoms and algae.
The larvae resembles small torpedoes.

27. Group 3: Semi-tolerant of pollution
Can survive lower levels of dissolved oxygen
Many feed on algae on detritus
Are able to survive higher levels of water contamination

28. Black Fly Larva 1/3 of an inch long
Black Heads (although a minority might be tan or brown)
Segmented Body
Often stuck by attachment discs to rocks in the stream
Tiny, leg-like appendage under the head

29. Midge Fly Larva Up to ½ inch long
One pair of tiny legs under the head and another pair at the back
A thin dark line (digestive track) can be seen in the body
Thin, slightly curved, segmented body
Present in all but the most polluted waters

30. Orb Snail Commonly found among lush growths of algae
Eggs are often found underneath rocks
Has a lung that allows them to live in waters with little dissolved oxygen
Will drop to the bottom of the water at even the slightest distrubance

31. Gilled Snail Rely on oxygen in the water for breathing Have gills
Soft body inside a hard, spiral shaped shell
Plate-like door can be closed by the snail for extra protection
Shells usually open on the right side if the point of the shell is held up
Semi-tolerant to pollution

32. Scud Scuds have a gray body between 5 and 20 mm long
They are found in shallow waters
Scud eat algae and detritus
Scud can live in a wide variety of water qualities and are semi-tolerant to pollution

33. Group 4: Tolerant of pollution
Able to survive the lowest levels of water quality
Do not need much dissolved oxygen in the water
Can survive high levels of pollutant contamination

34. Pouch Snail Has an opening on the left side instead of the right
Does not have a plate-like covering over the entrance to the shell
Normally indicate nutrient rich conditions and poor water quality

35. Aquatic Sowbug Has seven pairs of legs and a set of gills
It is a scavenger living on dead plants found at the bottom of the water body
Can live in very low levels of dissolved oxygen
Commonly found by sewage treatment plants or areas with a lot of farm runoff

36. Bloodworm Midge Larva Can tolerate VERY low dissolved oxygen levels
Often found in the sludge at the bottom of stagnant ponds
The larva eat detritus at the bottom of the pond and are actually useful in breaking down sewage

37. Leech
Leeches are considered indicators of very poor water quality, especially in running waters
Leeches have two suckers, one on each end of the body
They can survive low dissolved oxygen levels and high pollution levels

38. Tubifex Worm
Tubifex worms can exploit all dissolved oxygen by waving hemoglobin rich tails, allowing them to survive very low dissolved oxygen levels
They are able to survive areas heavily polluted with organic matter that no other species can endure
Tubifex worms can form a protective cyst and lower their metabolic rate, allowing them to survive food shortages and droughts

39. Macroinvertebrates in a Pond at Ashokan Field Campus
Pond Specs
Length- 165 feet Width- 107 feet (0.4 acres) Longitude- 74° ” W Latitude- 41° ” N Elevation- 406 feet Algal mats are present in several shoreline locations on the pond

40. Physical Characteristics of the Pond
Comments
Water Temperature °C Dissolved Oxygen- 5.2 mg/L Conductivity- 20 µS/cm pH Turbidity 13 NTU
Typical temperature for October; 3 degrees higher than Esopus Creek Relatively low (9-10 mg/L optimal) Relatively high turbidity

41. Procedure
The bottom of the pond was sampled at four locations with kick nets
Debris is kicked into nets by students in hip waders
The four samples were combined, and transferred to plastic buckets
Macroinvertebrates were picked out of debris and placed in petri dishes

42. Results Group 1 Macroinvertebrates
None of these species were present in our pond
Total found: 0

43. Group 2 Macroinvertebrates
NONE FOUND
NONE FOUND
NONE FOUND 14
NONE FOUND 11
NONE FOUND 10 18
Total found: 40

44. Group 3 Macroinvertebrates
NONE FOUND
NONE FOUND 2 9 23
Total found: 34

45. Group 4 Macroinvertebrates2
NONE FOUND
NONE FOUND
Total found: 2
NONE FOUND
NONE FOUND

46. Possible Sources of Error
Misidentification of macro invertebrates
Unable to see microscopic specimens
Looking in the wrong spots for certain species
Slow moving invertebrates hard to see
Variations in the pond ecosystem
Camouflaged or hidden specimens
Inexperience

47. C+ What is the pond’s GPA? 190 points divided by 77 specimens = 2.48
Class
Number
Points
Total Points
Group 1
x 4
Group 2 40
x 3
120
Group 3 34
x 2 68
Group 4 2
x 1
190 points divided by 77 specimens = 2.48
Water Quality Rating: fair C+

48. Explaining the Results
Who you gonna call?
Migratory birds can have major impacts on water quality

49. Waterfowl Damage in Ponds
It only takes 0.1 ppm of phosphate or 5-7 ppm of nitrate to reduce water quality in a pond
These rates can be reached in a pond with only 4.2 geese per acre of surface area; bird poop was plentiful in the adjoining field
At Ashokan, we saw 5 geese near a 0.4 acre pond
The field has not been farmed in decades

50. DEP Waterfowl Management
A Waterfowl Management Program was developed to evaluate and mitigate pollutant
impacts (fecal coliform bacteria) from migratory and resident waterbirds (waterfowl, gulls and cormorants).

51. What damage do birds do?
Onondaga County had to replace its reservoir with a storage tank due to bird droppings. Cost: $34 million
Kensico Reservoir in the City of New York water supply system has seen increases in fecal coliform bacteria in recent years

52. What has been done: Avian population monitoring
Depredation of waterfowl eggs
Avian harassment (dogs, motorboats, pyrotechnics)
Avian deterrence (nets and wires)

53. Ashokan Reservoir Waterfowl

54. Ashokan Reservoir Waterfowl

55. Ashokan Reservoir Waterfowl