1. Explore the Environment of Seneca Lake
Science on Seneca
Explore the Environment of Seneca Lake

2. Welcome to Hobart and William Smith Colleges
Welcome to Hobart and William Smith Colleges. Hobart and William Smith are two separate colleges: Hobart college for men was founded in 1822 and William Smith for women in The colleges offer a co-ed liberal arts education. The campus sits on 180 acres of land on the east side of Seneca Lake.
As part of your Science on Seneca experience you will be taken on a short tour of the scientific laboratories and other buildings of interest on campus. You will see first-hand how some of the data that is collected during the Science on Seneca field trips are utilized by college students and faculty at Hobart and William Smith to study the ecology of Seneca Lake.

3. Finger Lakes Region Watershed Area – 5000 km²
Drinking Water Supply Rochester, Syracuse, Ithaca, Geneva, Auburn
Tourism & Recreation
22 million tourists visit the region -generates $2.6 billion in revenue
Agriculture
45% Agricultural land use
35% Forested
From the City of Rochester in the West, to Ithaca in the South and Syracuse in the east, there exist eleven Finger Lakes that vary in size and depth. Seneca Lake is the largest and deepest of the lakes. Seneca holds half of the volume of water of all of the lakes combined. Almost all of the Finger Lakes serve as a drinking water supply for cities and towns in the region. They also attract many visitors, every year almost 22 million people come to the Finger Lakes to visit the wineries, state parks, or historic towns and cities in the region. Tax dollars from industries such as farming, tourism, and manufacturing provide a tax base that supports the infrastructure in the region, like roads, sewer treatment plants, and schools.

4. Science on Seneca Field Trip
Purpose: To learn more about the ecology of Seneca Lake while assisting in the collection and interpretation of scientific data on the lake.
Science on Seneca (SOS) is a high school educational outreach program of the Finger Lakes Institute at Hobart and William Smith Colleges. It was established in 1986 by the faculty at Hobart and William Smith Colleges, and is based on the environmental study of Seneca Lake. Science on Seneca has four objectives:
To enhance the teaching of environmental science in area high schools
To introduce students to environmental field studies using Seneca Lake as their laboratory
To expand the Seneca Lake database using long-term monitoring of this Finger Lake
To provide useful science content and standards based curricula for local and regional science teachers and students

5. Boat Etiquette The Boat William Scandling Captain John
A major portion of the visit to Hobart and William Smith will be onboard the William Scandling a 65 foot boat that serves as a floating classroom/laboratory on Seneca Lake.
The captain of the WILLIAM SCANDLING is Mr. John Nichols and the first mate is Mr. John Abbott. They are at your service while aboard the vessel and will be happy to try to answer any questions you might have about Seneca Lake, the ship, or any of its operations.
While aboard the WILLIAM SCANDLING, visitors may, with a few exceptions, go wherever they like. No visitors are allowed in the engine room or allowed on the "roof" of either the laboratory or the pilothouse.
Captain John

6. Data Collection: Physical Parameters
Transmission of Light – Secchi Disk
Wind Speed and Direction
Water Temperature Profile –
CTD
Physical Measurements
While on the boat students collect water samples and take measurements of the physical conditions of the water such as
Secchi Disk readings – the secchi disk reading tells you the clarity of the water which is an approximate measure of productivity in the lake, or how much microscopic plant life is growing. This in turn governs how far light can penetrate into the water column.
You will also record the wind speed and direction as wind can cause the surface of the water to become choppy and impact the depth to which you can see the secchi disk.
An instrument called a CTD will be lowered in the water by the crew. This instrument automatically measures temperature and other parameters throughout the water column. A reading will be printed out on the ship and given to your teacher.

7. Secchi Disk and Productivity
The secchi disk is used to measure the transparency of water. It is a weighted disk, 20 cm in diameter, and painted with two black and two white quadrants. It is slowly lowered into the water until it disappears, and this water depth is noted. The degree that sunlight can pass through water is a factor in a lake’s productivity because it governs the depth to which photosynthesis can take place. There is a correlation between how productive a lake is (i.e. how much photosynthesis is taking place) and secchi disk reading depths. However, variables such as roughness of the water, wind, and cloud cover can also affect water clarity and so those parameters are also noted when taking readings.
In very transparent waters (plankton poor waters) secchi disk depths can be 100 feet (30 m) or more in ultra-oligotrophic (low productivity) systems. In an eutrophic (highly productive) pond on a farm, secchi disk depths can be as shallow as a few centimeters.
Typically, a combination of these indicators, larger nutrient concentrations, larger algal
concentrations, and more shallow secchi disk depths are utilized to document the degree of
eutrophication and degree of water quality degradation in aquatic systems.
Productive Lake – algae bloom.

8. Water Temperature in Lakes
Cold water is more dense than warm water.
Thermocline separates the warm water from the cold water.
Water has a high specific heat index.
The layers of water in deep lakes like Seneca will stratify into three layers at certain times of the year. Water reaches its maximum density at 4 degrees celsius and will sink; any water layers that are warmer will lay on the top. During the summer months, the upper, warmer water layer is called the epilimnion. This layer of water is constantly mixed by wind and wave current. Below that layer is the thermocline, a zone where the temperature dramatically drops. This creates a barrier between the upper layers and the bottom layers of water (the hypoliminion). In the hypoliminion, water temperatures are typically 4-6 degrees Celsius.
The high specific heat index of water helps regulate the rate at which air changes temperature, which is why the temperature change between seasons is gradual rather than sudden. Because Seneca Lake is such a large body of water it is able to maintain the air temperature around the lake. Hence, vineyards in the region benefit from the cool air in the spring (delaying the onset of buds before the last frost) and warmer air in the autumn (extending the growing season and allowing the grapes to flourish).

9. Chemistry pH – pH meter Chloride – titration DO – titration Chemistry
On the boat you will also be measuring concentrations of certain chemicals in water samples from the lake.
pH – Most organisms survive in a pH environment between If the pH falls below 5 the water is too acidic for most aquatic life. Measuring pH is one way of measuring the impacts of acid rain on the lake ecosystem.
Chloride Ion Concentration – Seneca Lake has relatively high concentrations of chloride ion. Seneca Lake is a drinking water supply for towns around the lake. Although the concentrations of chloride are well below regulated standards for drinking water, the higher sodium concentration may pose long-term health impacts for people on restricted sodium diets.
Dissolved Oxygen – DO is essential for all aquatic life. When oxygen drops below 3 ppm there is not enough oxygen for fish to survive.

10. pH pH measures impact of acid rain on the lake.
Hardness is an indicator of the concentration of CaCO3.
Drinking Water Standards for Hardness and pH
Hard water is naturally likely to also have a high pH, because it is also high in carbonates that buffer the pH toward the alkaline side. pH levels can have an impact of aquatic life if they fall below 5. Hardness is considered a nuisance pollutant but is also an indicator of the type of bedrock found in an area.

11. Rain is naturally acidic but Seneca Lake’s underlying bedrock consists of Limestone which naturally neutralizes acid. When rain falls and flows through the streams in the watershed it interacts with the acid neutralizing soils and bedrock so that by the time it reaches the lake the pH values are higher.

12. Chloride in Seneca Lake
Chloride is measured because it serves as a proxy for sodium concentrations, as large sodium ion concentrations are a drinking water concern for certain individuals. One theory for the high levels of chloride sodium in Seneca Lake as compared to the other Finger Lakes is that the glaciers scoured the lake bed deeper in Seneca Lake than other lakes, deep enough that the lake intersects with rock-salt. Groundwater seepage may then transport NaCl into the water column of Seneca Lake more than in the other Finger Lakes.

13. Seneca and Cayuga Lake are so deep that the deepest points of the lakes are below sea level.

14. Factors Affecting Dissolved Oxygen
Water Temperature
Photosynthesis
Respiration
Aeration
Decay – uses up oxygen.
There are a number of factors that affect DO levels in lakes.
Temperature – colder water holds more oxygen so there may be seasonal fluctuations in DO readings, or DO may vary depending on the depth that the water sample was taken.
Photosynthesis – the rate of photosynthesis also affects the levels of Do in the water column. Plants give off Oxygen during photosynthesis.
Respiration – conversely aquatic organisms will affect DO by using up oxygen during respiration- the effect is often concentrated in summer, when aquatic animals require more oxygen to support higher metabolisms.
Aeration – Oxygen gets into the water by diffusion from the surrounding air. Wind and water movement will influence the levels of DO in a waterbody – hence you are likely to find higher levels of DO in a running body of water (stream) versus a still pond.
Decay - Decay of organic wastes consumes oxygen – the more organic wastes in a water body the more Oxygen depletion.

15. Biology
Biological Diversity – plankton nets to collect samples of plankton and zooplankton
Zooplankton (Daphnia)
Phytoplankton (Diatom)
The objective of studying the plankton diversity in Seneca Lake is to provide a basis for analyzing the lake’s ecology. Plankton are free-floating microscopic life that form the foundation of the food chain in a lake system. Phytoplankton are the primary producers, plant-like organisms that photosynthesize. Zooplankton which feed on plankton, are the next step in the food chain. Studying the diversity of these organisms provides an understanding of the quality of aquatic life in the lake. The diversity of organisms - i.e. the number of types of individual organisms and the relative abundance of the organisms – measures ecosystem stability.
Daphnia pulex
Astrerionella

16. Students using plankton net
In this slide you see students using a plankton net to capture a sample of plankton.

17. Plankton Sample
Once the plankton sample is collected you will view it under the microscope on the boat.

18. Sediment dredge
While on the boat the crew will collect samples of sediment from the bottom of the lake using the dredge.

19. Quaggas and Zebra Mussels
Quagga Mussel
Students sift through the sample of mud to look for organisms and test the sediment type. This is when student see first hand the invasive quagga and zebra mussel populations that reside on the lake floor.

20. What Happens to the Food Chain?
Fish and other organisms
Invasive Mussels
Grazers
In the early 1990s the zebra mussel was introduced to the Finger Lakes. The zebra mussels and the more recent invader the quagga mussel are filter feeders and feed on the phytoplankton in the lake. The mussels are not typically eaten by the organisms at the top of the food chain in the Finger Lakes. The invasive mussels have disrupted the food chain. Research is underway to examine the long-term implications.
Nutrients
Producers

21. Zebra Mussels and Seneca Lake Secchi Depths
This chart shows the correlation between the rise in zebra and quagga mussels in the Seneca Lake and water clarity. Once introduced into the lake zebra mussel populations grew rapidly until the population reached a crashing point in the late 1990’s. As the population of zebra mussels rose the secchi disk readings were higher – meaning greater water clarity. The red line shows this trend. What will the trend be now that quaggas are present in Seneca Lake? Scientists at the FLI are studying the densities of quaggas and zebra mussels in Seneca Lake to determine the potential impact these organisms might have on the ecosystem.
Zebra Introduction
Zebra Die Off
Zebra Rebound & Quagga Introduction

22. Geology Sediment Character
Lake sediments contain the record of the materials that have been deposited in the lake over geological time. From the study of lake sediments students gain an understanding of how materials deposit over time on the lake bottom and form layers of sediment that can be examined for an historical view and record of the living and non-living environment.

23. Life in Geological Time
Sediments contain clues as to the type of life that existed over time in the Finger Lakes.
For example students examining sediments during SOS 20 years ago would not have found zebra mussels because they did not inhabit Seneca Lake!

24. Science on Seneca Looking forward to seeing you!
Website:
Credits: Barb Busack, CABOCES; Sheila Myers, FLI; Sarah Meyer, FLI; Jim Makinster, FLI; Eric Primrose, FLI; John Halfman, FLI; plankton pictures by Wim van Egmond; Paleontological Research Institute, Ithaca NY.; Bob Dedrick, Canandaigua Schools.