Buoyancy and locomotion

These flashcards cover key concepts and terminology related to the functional and behavioral adaptations of marine organisms, focusing on buoyancy, locomotion, and the physical properties of water.

What are the key physical properties of water relevant to marine life?

Water is 800x more dense than air, 60x more viscous, incompressible, and provides three spatial dimensions for organisms.

What is the formula for calculating the sinking rate of marine organisms?

Sinking rate = (W1 - W2) / (R * V) where W1 is density of the organism, W2 is density of water, R is surface of resistance, and V is viscosity of water.

What are some strategies marine organisms use to reduce sinking?

Low density bodies, generation of lift with propulsion and hydrofoils, reduction of heavy structures, and gas bladders.

What defines planktonic organisms?

They are unable to move against flow and have limited motility, needing to remain in appropriate zones like the photic zone.

How do small volume organisms affect sinking rates in plankton?

Smaller organisms have higher surface area to volume ratios, which increases resistance and reduces sinking rates.

What role do gas bladders play in marine organisms?

They allow organisms to regulate buoyancy and maintain their position in the water column.

What distinguishes physostome and physoclist swim bladders in fish?

Physostome bladders connect to the oesophagus and allow gulping of air, whereas physoclist bladders are not connected and have limited filling and emptying.

How do red and white muscle types differ in marine animals?

Red muscle is rich in myoglobin and supports endurance, while white muscle is more suitable for rapid acceleration.

What are the two main types of drag affecting swimming in water?

Pressure drag and friction drag.

How do fish reduce drag while swimming?

By secreting mucus to reduce friction and having hydrodynamic body shapes to reduce pressure drag.

What swimming style is characterized by lateral waves along the entire body?

Anguilliform swimming, typically seen in eels and oarfish.

What is the main characteristic of carangiform swimming?

Body is thrown into shallow waves with larger amplitude at the caudal fin.

What is the role of rete mirabile in deep water fish?

It facilitates gas exchange and helps manage buoyancy by maintaining gas concentration in the swim bladder.

How does pressure change with depth in the marine environment?

Hydrostatic pressure increases linearly with depth, approximately by 1 atmosphere (1 \text{ atm}) for every 10\text{m} of depth.

How do marine organisms use ionic substitution for buoyancy?

Organisms replace heavier ions, like \text{SO}4^{2-} or \text{Mg}^{2+}, in their body fluids with lighter ions, such as \text{NH}4^{+} or \text{Cl}^{-}, to reduce overall density.

What is the difference between holoplankton and meroplankton?

Holoplankton spend their entire life cycle as plankton, whereas meroplankton reside in the plankton only during their larval stages before becoming nekton or benthos.

What is the Reynolds number (Re) and why is it important in marine biology?

The Reynolds number is a dimensionless value representing the ratio of inertial forces to viscous forces (Re = \frac{\rho v L}{\mu}); it determines whether an organism's movement is dominated by friction or momentum.

How do sharks achieve buoyancy without a swim bladder?

Sharks utilize a large liver filled with squalene, a low-density oil, and rely on dynamic lift generated by their heterocercal tails and pectoral fins.

What is the effect of Boyle's Law on fish swim bladders?

Boyle's Law states that volume is inversely proportional to pressure (P \propto 1/V); thus, as a fish descends and pressure increases, the swim bladder gas compresses, requiring more gas to maintain buoyancy.

What are the characteristics of thunniform swimming?

Thunniform swimming is the most efficient high-speed style where lateral movement is strictly limited to the caudal fin and the narrow peduncle, minimizing drag.

What is labriform swimming?

A swimming style where propulsion is generated by the oscillating or rowing motion of the pectoral fins, common in coral reef fishes for high maneuverability.

How does the Bohr effect assist in gas secretion into the swim bladder?

Lactic acid production near the rete mirabile lowers blood pH, which reduces the affinity of hemoglobin for oxygen (Bohr effect) and its carrying capacity (Root effect), forcing oxygen into the bladder.

What is skin friction drag and how is it minimized?

Skin friction drag is caused by the viscosity of water sliding over the body surface; it is minimized by reducing surface area and secreting lubricating mucus.

Why is the aspect ratio of the caudal fin significant?

The aspect ratio (\text{Span}^2 / \text{Area}) determines efficiency; high aspect ratio fins (like those in tuna) provide high thrust with low drag for sustained cruising.