Biodiversity and oil spills
Age and growth
Trophic interactions
Grab bag 1
Grab bag 2
100
When did the Deepwater Horizon oil spill occur?
April 20-July 15, 2010
100
What are otoliths and why are they important to fisheries scientists?
Calcium carbonate earstones in teleost fish Important for age and growth studies
100
What are the characteristics of upper versus lower trophic levels?
Upper: few large organisms Lower: many small organisms
100
Pelagic organisms are divided into 2 groups based on locomotion: what are they?
Plankton: drift passively on the horizontal plane Nekton: capable of overcoming horizontal currents by swimming
100
What is an estuary?
Transition between marine and fresh water biomes
200
What variables affect the severity of an oil spill?
Magnitude of spill (volume spilled & surface area covered) • Oil composition • Environmental conditions (temperature, wind, ocean currents, etc.) • Habitat (e.g. rocky shore vs. marshes) • Fauna and flora • Cleanup efforts, use of dispersants, etc. • Synergist effects with other phenomena, e.g. habitat loss, overfishing, hypoxia, etc.
200
Besides age and growth, what can otoliths be used for?
Stock Identification • Natural Tag – Migration history • Reconstruction of environmental history • Pollution • Physiological indicators
200
Why are trophic interactions important to study in ecology?
Linkages and dynamics in aquatic food webs have a direct impact on fisheries and ecosystem productivity
200
What are the 5 seagrasses found in Texas?
Shoal (Halodule wrightii) Manatee (Syringodium filiforme) Turtle (Thalassia testudinum) Star (Halophila englemanii) Widgeon (Ruppia maritima)
200
What are the 2 genera of mangroves most commonly found in the Gulf of Mexico?
Rhizophora (red) and Avicennia (black)
300
Why are dispersants an issue for organisms?
Allows oil to cross biological membranes, making it bioavailable to more organisms
300
Describe 3 approaches are used for age determination of fish
Empirical: Least Used Direct Observation Mark and recapture Statistical: Not Reliable Based on length frequency data Assume length is normally distributed Anatomical Most Used Age with hard parts Time consuming
300
What are 4 types of trophic interactions?
Direct consumptive (lethal) Direct consumptive (sublethal) Direct behavioral (nonlethal) Indirect consumptive
300
What forms can oil+water take?
Oil slick, mousse, tar balls, sandy patties
300
Remotely sensed observations have to distinguish between “Case 1” and “Case 2” waters. Describe the difference between the two:
• Case 1: Ocean color is determined predominately by algal pigments • Case 2: Particulate matter dominates ocean waters.
400
How can crude oil impact organisms?
Hypothermia, endocrine disruption, ingestion of toxic oil, drowning, immune system issues, breeding issues (thin eggs, developmental damage)
400
Besides otoliths, what other hard parts can be used for age determination?
Scales, fin rays and spines, vertebrae
400
What are advantages and disadvantages of direct observation versus tagging / tracking?
Direct: labor intensive, short term, biased by location, time period Tagging/tracking: large animals only, expensive, initially labor intensive
400
What are fronts and meanders? Why are they important?
Horizontal boundaries between water masses with different physical properties are known as fronts – e.g. Loop current in the GoMx • Meanders in fronts can lead to columns of water (warm or cool core rings) being shed – Important mechanism for transoceanic mixing – Impacts strength of tropical storms
400
Describe the match-mismatch hypothesis
Larval fish survival greatest when the period of plankton production overlaps most closely with the period of larval food demand (may reduce starvation)
500
Why is the Deepwater horizon called the "new paradigm" for oil spills
Deep Dispersants at depth Deepwater plumes of oil
500
Besides just counting rings, otoliths are also studied for their microchemistry. What can this tell us?
Distinguish nursery areas • Examine movement patterns • Elements associated with anthropogenic sources are useful • Signatures can vary by year
500
What are different methods for performing a diet analysis?
Gastric lavage Physical removal of stomach contents Stable isotopes manipulative experiments
500
Describe the difference between Eulerian and Lagrangian points of view
Eulerian: clam's eye Lagrangian: fish eye
500
What are regime shifts?
Large, abrupt, persistent changes in the structure and function of a system, between ‘multiple stable states’ • Usually occurs when a smooth change in an internal process or a single disturbance triggers a completely different system behavior
M
e
n
u