Section 3: Dynamic Coastal Waters and the Food Web

Focal Questions: What can we predict about critters using observing systems?
What is the link between critter habitat and physical conditions?
Ocean Literacy / NSES:   5b, 5f, 5h, 5i, 7d, 7f

 

Introduction:
Activity: Hatch to Catch

Science Overview:
Striped bass scales and life-history tales: fish and physics in Chesapeake Bay
Dr. Elizabeth North

Classroom Activity:
Where Could the Stripers Be?
Where do the Critters live?

Field Trip / Lab:
Assessing Dynamic Coastal Waters Effect on the Food Web

 

Introduction

Ocean circulation has a direct impact on the organisms that reside in the ocean. Distribution and migration of fish populations, for example, can depend on how wind and residual currents transport eggs and early life stages. Circulation and climate can affect variability in growth, maturity, recruitment and mortality. The distribution of zooplankton plays a role in fish growth, distribution and survival -- all of which may be affected by climate. As scientists gather more information about climate, circulation and their impact on organisms, the goal is to use the information to set medium and long-term management objectives for possible future climate scenarios, and strategies for dealing with the uncertainties these scenarios may bring.

 

Introduction Activity - Hatch to Catch
Annette deCharon and Nicholas Wolff

Objective: Students will be able to list at least three limiting factors for successful life cycles in lobsters.

Background

The activity is meant to serve as a guided exploration of the Web site, http://www.bigelow.org/hatch_to_catch/, with all students following a single scenario under the direction of the teacher.

Some of the needs/limiting factors for successful life cycles of lobsters includes currents, depth, temperature and bottom type. For more information go to http://penbay.net/lobster.htm.

Materials

Computers with Internet access
Student worksheet

Procedure

1. Post the following "rules" in the room, either on a large sheet of paper or board and review with group before starting.

Lobster "rules" to remember:

1) Temperature controls how long the larvae will take to develop through stages.
2) Speed determines how far the larvae will travel before they are ready to settle.
3) Settled lobsters grow more quickly in warmer waters, in general, Gulf of Maine waters are colder at depth.
4) Think about the bottom type lobsters might need for protection. Choose from ledge, sand, cobble, mud or diverse.

2. Play "Hatch to Catch" http://www.bigelow.org/hatch_to_catch/

Scenario 1 - Nova Scotia

3. Read the first screen and click "Continue"
4. Read the second screen and click "I'm Ready to Play"
5. Click "Choose Hatch Area"
6. Click "Go 'ta' Nova Scotia"
7. Click "Offshore" Spot
8. Watch animation run to see which direction the currents are pushing the larvae. Each dot represents 5 days of travel.
9. Click "Data/Settle"
10. Read the stats.
11. Click on "Settle Here"
12. Click on "Settle Now"
13. On the Student Worksheet, record settling depth, water temperature, bottom type and how many original lobsters grew and to what stage did they mature. Would this be a good place for lobster larvae to settle?
14. Click the "back" button on your browser.
15. Click "Delay 3 Days"
16. On the Student Worksheet, record settling depth, water temperature, bottom type and how many original lobsters grew and to what stage did they mature. Would this be a good place for lobster larvae to settle?
17. Click the "back" button on your browser
18. Click "Delay 6 Days"
19. On the Student Worksheet, record settling depth, water temperature, bottom type and how many original lobsters grew and to what stage did they mature. Would this be a good place for lobster larvae to settle?

Worksheet: "Hatch to Catch"

Lobster "rules" to remember:

1) Temperature controls how long the larvae will take to develop through stages.
2) Speed determines how far the larvae will travel before they settle.
3) Settled lobsters grow quicker in warmer waters, in general, Gulf of Maine waters are colder at depth.
4) Think about the bottom type lobsters might need for protection. Choose from ledge, sand, cobble, mud or diverse.

Nova Scotia - Offshore

"Settle Now"
Settling depth:    Water temperature:    Bottom type:

How many original lobsters grew and to what stage did they mature?
Would this be a good place for lobster larvae to settle?

"Delay 3 Days"
Settling depth:    Water temperature:    Bottom type:

How many original lobsters grew and to what stage did they mature?
Would this be a good place for lobster larvae to settle?

"Delay 6 Days"
Settling depth:    Water temperature:    Bottom type:

How many original lobsters grew and to what stage did they mature?
Would this be a good place for lobster larvae to settle?

What are the needs/limiting factors for successful life cycles of lobsters?

Do you think other species might have similar limiting factors?

How might real time data help lobster/fisheries resource managers?

 

Science Overview

Topic: Fish and physics in Chesapeake Bay

This presentation is meant to be a teaching tool that demonstrates the link between striped bass habitat and physical conditions such as currents, water temperature, salinity and dissolved oxygen. Striped bass hatch as tiny larvae that can grow to be 1000 times larger than they started. They are influenced by physical conditions at every stage in their life cycle, from larval drift, to growth and feeding, to adult spawning. Habitat quality for striped bass varies as currents, water temperature, salinity and dissolved oxygen change in different seasons. Monitoring programs and observing systems are important tools that scientists and managers use to better understand how physical conditions influence striped bass and inform fisheries and ecosystem management.

Dr. Elizabeth W. North

Education:
1991   B. A., Swarthmore College, Religion
1996   M. S., Johns Hopkins University School of Continuing Studies, Interdisciplinary Science Studies, concentration in Environmental Science
2001   Ph.D., University of Maryland College Park, Marine-Estuarine-Environmental Science, specialization in Fisheries Science

Position:
Assistant Professor
University of Maryland Center for Environmental Science, Horn Point Laboratory

What I do:
Research Interests: Biological-physical interactions: circulation and particle trajectory modeling, larval fish and zooplankton ecology, fisheries recruitment variability, estuarine and coastal physical oceanography

 

Classroom Activities

Where could the stripers be?

Objective: Students will be able to used real time data to locate striped bass

Background

This is a web-based activity that uses information on striped bass habitat preferences and water temperature and dissolved oxygen to understand where striped bass can be found in Chesapeake Bay. Users are asked to answer a series of questions about the potential location of striped bass by following links to monitoring programs and observing systems for recent information on physical conditions in Chesapeake Bay. This activity is based on the presentation "Striped bass scales and life-history tales: fish and physics in Chesapeake Bay". Both the activity and an abbreviated version of the talk are available on the web at: http://northweb.hpl.umces.edu/education_outreach/education_outreach.htm

Classroom Activities

Where do the critters live?

Objectives : 1) Students will be able to use the computer to find real time data

2) Students will be able to correlate real time data to predict suitable habitats of various aquatic organisms.

Background

Aquatic organisms are greatly affected by various abiotic factors such as temperature, salinity, dissolved oxygen, and depth. Listed below are the optimum tolerance ranges for various species.

1. Blue Crab – mature males winter buried in sediments of estuaries
- mature females winter in the deep water of the bay
- juveniles live in shallow water habitats
- mating takes place in low salinity in upper estuary and low
portions of the water in warm water
- hatching occurs in 19-29 C and 23-33 ppt. salinity
- optimum for adults is 3-15 ppt.

2. Stone Crab – eggs 28 C and 28-36 ppt. and depth subtital
- larvae 28-30 C and 30 ppt.
- juvenile 12-32 C and 20-35 ppt.
- adults 15-35 C and 15 ppt.

3. Horseshoe Crab – spawning on sandy beach above 7 ppt.
- juveniles like shallow water greater than 5 ppt.
- adults less than 30 m deep and 35 C and 20-30 ppt.
- size is related to temperature, the warmer the larger

4. Atlantic Sturgeon – spawning 13-21 C and brackish/fresh water
- eggs need 18-20 C
- larvae/juveniles migrate to brackish water when below
20 C
- adults 5-30 C and 0-35 ppt.

5. Shortnose Sturgeon – spawning 9-15 C in fresh flowing water
- adults 5-30 C and 0-21 ppt.
6. Sea Nettles – 26-30 C and 10-20 ppt.

7. Ctenophores – 7-32 C minimum and 5-18 ppt.

8. Striped Bass – spawn fresh water
- adults 12-14.5 C and 5-10 ppt.

9. Greater Amberjack – adults 31-34 C and 29.8-36.3 ppt.

10. Wild Celery Grass – 33-36 C and 0-5 ppt.

11. Redhead Grass – 25-40 C and 5-18 ppt.

12. Eelgrass – 0-30 C and 18-30 ppt.

13. Turtle Grass – 10-35 C and over 28 ppt.

14. Widgeon Grass – 18-30 C and 0-40 ppt.

Materials

Procedure

  1. Select 7 organisms and include 2 types of grass in your
    selection.
  2. Write down your organisms on the data sheet.
  3. Select 10 buoys and decide which of your organisms can survive at
    that site for this day.
  4. Use http://nautilus.baruch.sc.edu/carocoops_website/index.php or http://tidesandcurrents.noaa.gov/parts.html or
    http://marine.rutgers.edu/cool/projects/oceanrobots.htm or
    http://www.vims.edu/realtime/ or
    http://www.gomoos.org/buoy_data.shtml (use red sites)
    to get your real time data and record your information on the data sheet.
  5. If you need to convert Fahrenheit to Celsius, use (F -32) * 5/9 = C.

 

Field Trip

Assessing Dynamic Coastal Waters Effect on the Food Web
Deidre Gibson

Questions  How does the physical environment affect biology?
Comparison of organisms associated with Estuarine Turbidity Maximum (ETM) zone

Laboratory  Identification of organisms found in the ETM

Objective:  Participants will investigate the affects of physical parameters on the distribution and abundance of organisms.

Background

The life and distribution of marine organisms depend on the ocean's chemical composition and physical characteristics. Any aspect of the physical environment that affects living organisms is called a physical factor. Physical conditions in the ocean are milder and less variable than those in the estuary and on land. The most important physical factors for marine organisms are light, temperature, salinity, dissolved nutrients and gasses, and a few others.

The Estuarine Turbidity Maximum (ETM) is a region located near the head of the salt front and plays a significant role in entrapment of sediments planktonic organisms and fish. It is hypothesized that the ETM entraps sediment particles and planktonic organisms which in turn support enhanced zooplankton production and both growth and survival of young fish.

The purpose of the field trip is to determine if the physical factors in and around the ETM affects production and distribution of organisms.

In the field we will measure temperature, salinity, oxygen and turbidity using a Yellow Springs Instruments (YSI) to determine the location in and around the ETM. We will conduct net tows to collect organisms using a 200 µm mesh plankton net.

In the lab we will use a dissecting microscope to identify and estimate the organisms collected in and around the ETM.

Materials:

Field
2 Boats
2 YSIs
2 Plankton nets
2 Secchi disks
2 buckets
Data sheets

Lab
Microscopes
Petri dishes
Data sheet
Identification books

Field Procedure

Locate the ETM. Using the YSI record the surface temperature, salinity, dissolved oxygen, and turbidity by using the secchi disk, and record information on the data sheet.

Lower the plankton net into the water and tow on the surface for 5 minutes at 1 knot. Dilute the contents of the tow into a bucket of ambient water to assure viability of the organisms.

Lab Procedure

Take small aliquot samples from the bucket, place in a petri dish to observe live organisms.
Use the identification key to identify the organisms. We will do a visual estimate of abundance.

Questions:

Was there a significant difference in the organisms found in and near the ETM?
Explain your answer.

Data Sheet

Field

Station#
Time
Depth
Temp. (C)
Salinity
DO (mg/l)
Turbidity (m)

Lab

List of Organisms:

 

Laura Murray and Deidre Gibson, Editors