Marine Science Field Trips, Lab Activities, and Oceanography Overview

Freshwater Influx and Chemical Oceanography

The course blends chemical oceanography with biology; freshwater influx affects coastal systems and can influence organisms (e.g., dolphins can develop freshwater lesions if exposed too long).
Heavy rainfall in Northern Alabama can take about 5\text{--}7\text{ days} for water from the Delta to reach Mobile Bay, bringing large amounts of freshwater and often muddy/murky water.
When freshwater meets saltwater, density-driven stratification creates visible color differences and a foam line at the interface; this stratification is a key topic for later labs.
The instructor teases integration of physical and biological concepts through field observations and lab work.
Primary producers and consumers mentioned: phytoplankton, zooplankton; invertebrates; planned dissections of invertebrates and vertebrates (fish and a shark).
A broader view includes reptiles and other groups in later activities.

Density, Stratification, and Water Mass Interactions

Two major water masses collide near the coast, creating a sharp density contrast and a visible transition zone in the water column.
Warm water is less dense than cold water; fresh water is less dense than salt water. This leads to a freshwater lens on top of saltier water and to density-driven layering.
The “foam line” and color differences can be used to visually identify stratification; a future lab will explore bathymetry and density effects in more depth.
Conceptual recap: density differences govern vertical structure and mixing in coastal waters.
Notation: to illustrate the density concept, one may consider \rho{\text{fresh}} < \rho{\text{salt}} and the freshwater lens perched above denser seawater.

Field Trips, Scheduling, and Safety

Four field-trip options exist; three are on the island and one is an option that does not require leaving campus.
You must choose exactly one field trip, but the instructor hopes students participate in all activities; the three island trips plus one no-travel option provide flexibility for conflicts (work, sports, family).
Boat trip options: one of the field trips is a boat trip with three different time slots; you pick one slot.
Trip length and conditions: a four-hour trawl trip is used for field observations; trips are weather dependent; safety considerations are emphasized (seasickness precautions, etc.).
The trawl table area is a focal point for collecting specimens; the crew prioritizes safety and rescuing protected species if encountered.
The goal of field trips is to provide exposure to things students wouldn’t otherwise see, with varying levels of student involvement depending on interest.

The Trawl Trip: Equipment, Rules, and Observations

The four-hour trawl trip uses a large net pulled along the ocean floor for roughly thirty minutes per tow; this duration allows time to rescue endangered species if encountered (e.g., dolphins, turtles).
It is illegal to retain dolphins or turtles; the tow duration ensures safe rescue opportunities.
The aboard setup includes an air-conditioned cabin, two small exterior bathrooms, outdoor seating along the bottom, and the option to stand on the top deck if weather permits (watch for seasickness).
The “trawl table” is a back surface where organisms collected are examined; a live well keeps larger specimens temporarily en route to lab study.
Common catches in the trawl include remoras (shark suckers), smooth butterfly rays (which lack a venomous barb and are safe to handle), various rays, and juvenile hammerhead sharks on rare occasions; other catches can include hog chokers, drums, chokers, and flounder.
The field trips are designed to be interactive: students can observe, assist with the trawl table, or take a more passive role depending on interest.
Occasionally unusual catches occur (e.g., a bird picked up during a trawl) demonstrating the ecological richness of the sampling area.

Dune and Shoreline Ecology: Audubon Sanctuary and Dunes

A field stop includes walking through the Audubon Bird Sanctuary, a protected area, leading to coastal dunes.
The dunes provide an attractive, accessible ecosystem for observing coastal processes and wildlife; a potential date-night spot is mentioned for its beauty.
The dunes illustrate how coastal habitats interface with the open water and offer opportunities for qualitative observations.

Plankton, Marine Microscopy, and Early Life Stages

Tiny plankton nets are used to sample water and collect microscopic organisms; the mesh is designed to capture very small organisms.
Plankton is defined as organisms that cannot swim against the current; phytoplankton are photosynthesizers (algae), while zooplankton are animals.
Ichthyoplankton are fish eggs/larvae that start out unable to swim upstream until they develop swimming muscles.
A stained sample of zooplankton is shown for better visualization; students will view similar specimens under the microscope in labs.
Labs include multiple microscopy activities and dissections of various small organisms to illustrate life cycles and anatomy.

Dissections: Invertebrates and Vertebrates

Dissection schedule includes two weeks of dissections after midterms; options exist for students who are uncomfortable with dissections, including a 3D paper model alternative.
Invertebrate dissections planned: clam and sea urchin; sea stars are largely avoided due to sea star wasting syndrome.
Sea star wasting syndrome is discussed: historically unclear causes, but recent work suggests a bacterial agent (not polio-like), and ongoing research continues to elucidate drivers.
Vertebrate dissections include a spiny dogfish shark (smaller size) to study internal anatomy; lab coats are now provided and face masks are optional; preservation smell is noted and mitigated with optional Vicks.
The shark anatomy discussion highlights the absence of a swim bladder and the presence of a large oily liver; this is related to their buoyancy strategy.

Cephalopods: Camouflage, Color, and Behavior

Squid behavior: in male-male fights, coloration can split: one side appears calmer (toward the female) while the other side uses more aggressive colors toward rivals; color changes are rapid and behaviorally driven.
Experiments mentioned include nerve cuts to the color-control pathway; even after nerve section, color change can persist for a few days, suggesting a reflexive or autonomic control mechanism that parallels breathing (metaphor used by instructor).
Cuttlefish and octopus examples: cuttlefish show impressive skin texture and color changes for camouflage; octopuses can resemble rocks or algae and can move across the seabed by using camouflage and motion to avoid detection; ink release as a defensive strategy is demonstrated.
The shallow-water cephalopods provide insights into sensory-mens-born camouflage and predator avoidance; examples emphasize rapid adaptation to surroundings.

Deep-Sea Adaptations and Exploration: Beyond the Reef

The class discusses a vivid illustration of a deep-sea creature and contemplates encountering such animals in situ.
Deep-sea adaptations include protrusible jaws and the ability to extend the mouth forward to capture prey; many deep-sea fishes lack a swim bladder and rely on a large, oily liver and minimal muscle activity to conserve energy; they have big mouths to exploit prey larger than themselves.
A contrast is drawn between shallow-water predators with robust coloration/display and deep-sea creatures with extreme jaws and camouflage strategies.
The instructor emphasizes that while we may never encounter such creatures in person, understanding their biology helps explain energy budgets and feeding strategies in resource-scarce environments.

Oceanography, Feeding, and Contamination: Manatees, Jellies, and Plastics

Jellyfish and related taxa discussed: Moon jellies are common and have stinging cells but generally cannot pierce human skin; Portuguese man-of-war is more dangerous and can cause painful stings; both can wash ashore and pose hazards to beachgoers.
Sea turtles are all endangered across species; females nest on beaches from late May to early June, returning to the same beaches to lay eggs due to natal imprinting; nests are protected by turtle patrol volunteers who monitor tracks and set up roping for nesting sites.
entanglement risk: debris, including chairs, can wash up and injure sea turtles; careless beach activity can lead to entanglement and stress for turtles.
DO (dissolved oxygen) variability: pockets of low DO cause erratic behavior in shrimp, crabs, flatfish, hog chokers, and sometimes juvenile sharks near shore during low-DO events; warm water around shore contributes to DO dynamics.

Sea Turtles and Human Interactions

All sea turtle species are endangered; females lay eggs during nesting season (late May/early June) on Dauphin Island beaches and others along the Gulf coast; hatchlings begin their journey to the open ocean after incubation.
Sea turtles rely on lung respiration and must surface to breathe; increased human activity and entanglement from debris pose significant risks to their populations.
Volunteers for sea turtle patrol monitor tracks and help protect nests; public education discourages touching sea turtles or disturbing nesting sites.

Environmental and Research Notes: Plastics and Marine Debris

Marine debris and plastics are highlighted as a concern; microplastics have been found in fish that humans eat; Dr. Martin's lab is researching this issue; findings suggest widespread plastic contamination.
Students are reminded to bring snacks (lab space is limited for eating); food is not allowed in labs; safety and cleanliness are emphasized.

Canvas, Course Materials, and Access

The instructor directs students to Canvas for course materials, separate lab and lecture pages, and Connect assignments; links should be accessed through Canvas rather than external sites.
EText and syllabus are accessible via Canvas; the syllabus link provides a downloadable document for review.
Weekly updates and reminders are posted on Canvas to help students stay on track and aware of any broken links or changes in the schedule.

Notable Concepts and Takeaways

Field-based learning integrates physical oceanography (density, stratification) with biology (organisms, life cycles) for a holistic understanding of coastal ecosystems.
Practical skills include identifying crab sexes and egg masses, recognizing benthic and pelagic organisms, and understanding the ecological consequences of harvesting vs. protection (e.g., female crabs with eggs).
Camouflage and sensory adaptation are central to cephalopod biology; these organisms showcase sophisticated neural and behavioral control of skin color and texture.
Deep-sea biology highlights energy conservation strategies, specialized anatomy (e.g., large mouths, lack of swim bladders, oily livers), and extreme morphologies that enable survival in dark, high-pressure environments.
Human impacts (do not disturb nesting sea turtles, avoid chasing or handling wildlife) and environmental stewardship (lionfish invasion, plastic pollution) are emphasized throughout.

Formulas and Quantitative References

Freshwater influx period: 5\text{--}7\text{ days} from Delta to Mobile Bay.
Boat/trawl trip duration: T = 4\text{ hours} (four-hour trawl trip).
Trawl tow duration (approximate): t \approx 30\text{ minutes} per tow.
Depth reference: Mariana Trench depth mentioned as d \approx 11{,}000\ \text{km} (note: this value is explicitly stated in the transcript; real-world depth is ~11,000 m).
Density relationships: \rho{\text{fresh}} < \rho{\text{salt}} to explain freshwater lens atop seawater.