APES Unit 4: Oceans in Action

Fishery

A commercially harvestable fish population in a specific ecological region.

Fishery Collapse

A 90% or more decline in a fish population.

Tragedy of the Commons

A situation where individuals exploit a shared resource, leading to depletion.

Bycatch

The unintentional catch of non-target species while fishing.

Purse Seine Nets

Large nets used to encircle and trap schools of fish.

Bottom Trawl Nets

Nets that drag along the ocean floor, catching fish and damaging habitats.

Midwater Trawl Nets

Nets pulled through the ocean, targeting mid-depth fish.

Gill Nets

Stationary nets with holes that trap fish.

Longlines

Fishing lines with thousands of baited hooks.

Quota System

A fishery management approach where fishers are given a specific allowable catch limit.

Sustainable Fisheries Act (1996)

U.S. legislation prioritizing conservation and species sustainability.

Keystone Species

A species that plays a crucial role in an ecosystem's stability.

Factory Ships

Large vessels that catch, process, and freeze fish at sea.

Seafood Watch App

A consumer guide to sustainable seafood choices.

Island Biogeography

The study of how species are distributed and interact on islands.

Species-area curve

A description of how the number of species on an island increases with island size.

Species richness

The number of different species present in a given area.

Log scale

A scale where values are plotted using logarithms, often turning curved relationships into straight lines.

Colonization

The process by which new species arrive and establish in a habitat.

Extinction risk

The probability of a species dying out in a given area.

Habitat diversity

The variety of different environmental conditions available in an area.

Trophic levels

Different levels in a food chain, including producers, consumers, and predators.

Ecological efficiency

The percentage of energy transferred from one trophic level to another (typically 10%).

Primary consumers

Herbivores that feed on plants.

Secondary and tertiary consumers

Carnivores that feed on other animals.

Predator-prey relationship

The interaction between species where one organism eats another.

Recruitment

The survival of young organisms into a later life stage (e.g., seedlings growing into saplings).

Overgrazing

Excessive feeding by herbivores, leading to habitat degradation.

Immigration Rate

The rate at which new species arrive and establish on an island.

Extinction Rate

The rate at which species go extinct on an island.

Dispersal Ability

The ability of a species to move from one location to another.

Habitat Island

A habitat isolated from similar habitats, functioning like an actual island (e.g., mountaintops).

Equilibrium Theory of Island Biogeography

A model explaining species diversity on islands based on immigration and extinction rates.

Fumigation Experiment

A controlled experiment where an island's species are removed and recolonization is observed.

Specialist species

Species adapted to specific conditions with limited diet and habitat range.

Generalist species

Species that can thrive in a variety of environments and diets.

Invasive species

Non-native species that spread rapidly and negatively impact native species.

Predator defenses

Adaptations that help species avoid predation, which island species often lack.

Avian malaria

A disease that affects birds, introduced to Hawaii by invasive mosquitoes.

Aquatic Biome

A large community of plants and animals that occupies a distinct region defined by its water characteristics.

Freshwater Biome

Ecosystems with low salt concentration, including lakes, rivers, streams, and wetlands.

Marine Biome

Saltwater ecosystems, such as oceans, coral reefs, estuaries, and mangroves.

Estuary

A transitional zone where freshwater from rivers meets and mixes with saltwater from the ocean.

Wetlands

Areas where water saturates the soil, either permanently or seasonally, supporting aquatic plants.

Salinity

The amount of salt in a body of water, influencing species survival and drinking water usability.

Depth

Determines how much sunlight reaches underwater plants for photosynthesis.

Flow

Affects which plants and organisms can survive, as well as oxygen levels in water.

Temperature

Warmer water holds less oxygen, affecting aquatic life.

Rivers

High oxygen due to water flow, carry nutrient-rich sediments.

Lakes

Standing bodies of freshwater, key drinking water sources.

Littoral Zone

Shallow water with emergent plants.

Limnetic Zone

Sunlit surface layer where photosynthesis occurs.

Profundal Zone

Too deep for sunlight, no photosynthesis.

Benthic Zone

Murky bottom with nutrient-rich sediments and invertebrates.

Wetlands

Areas where soil is submerged for part of the year but shallow enough for emergent plants.

Benefits of Wetlands

Reduce flooding, recharge groundwater, filter pollutants, high biodiversity.

Estuaries

Where rivers meet the ocean, mixing freshwater and saltwater.

Salt Marshes

Coastal wetlands in temperate climates, breeding grounds for fish and shellfish.

Mangrove Swamps

Coastal wetlands in tropical climates, home to mangrove trees that stabilize shorelines.

Coral Reefs

Highly diverse ecosystems where coral and algae have a mutualistic relationship.

Intertidal Zones

Coastal areas between high and low tides, home to species adapted to wave action.

Open Ocean Photic Zone

Sunlit layer where photosynthesis occurs.

Open Ocean Aphotic Zone

Deeper, dark layer with little productivity.

Lithosphere

The rigid outer layer of Earth, including the crust and upper mantle.

Asthenosphere

A semi-fluid layer beneath the lithosphere that allows tectonic plates to move.

Plate Tectonics

The scientific theory explaining how Earth's plates move.

Divergent Boundary

Plates move apart, forming new crust (e.g., seafloor spreading).

Convergent Boundary

Plates move toward each other, causing subduction or mountain formation.

Transform Boundary

Plates slide past each other, causing earthquakes.

Aquaculture

The breeding, rearing, and harvesting of aquatic organisms in controlled environments.

Mariculture

The cultivation of marine organisms in the open ocean or enclosed ocean sections.

Polyculture

Farming multiple species together to improve sustainability.

Integrated Multi-Trophic Aquaculture (IMTA)

A system where different trophic levels are farmed together to reuse waste as nutrients.

Carrying Capacity

The maximum number of individuals an environment can support without degradation.

Ecological Footprint

A measure of human impact on Earth's ecosystems, including resource use and waste generation.

Biodiversity Hotspots

Regions with high biodiversity that are under threat from human activity.

Eutrophication

Excess nutrient runoff (often from agriculture) leading to algal blooms and dead zones in aquatic systems.

Trophic Cascade

The impact of predators on lower trophic levels, influencing entire ecosystems.

Anthropogenic Climate Change

Human-caused changes in climate, affecting ocean temperatures and acidity (coral bleaching).

Hypoxia & Dead Zones

Low-oxygen areas in bodies of water caused by pollution and excessive nutrient input.

Overfishing

The excessive harvesting of fish beyond sustainable levels, leading to population declines.

Pollution from Aquaculture

Waste and uneaten food in fish farms can cause water contamination.

Disease Spread in Aquaculture

High fish density in farms can lead to diseases that may spread to wild populations.

Escape Risk in Aquaculture

Farmed fish that escape can disrupt natural ecosystems by outcompeting native species.

Polyculture Systems

Raising multiple species together to mimic natural ecosystems and reduce environmental impact.

Specialist Species

Organisms that thrive in specific conditions but struggle with environmental changes.

Generalist Species

Organisms that can survive in various environments and compete well with specialists.

Invasive Species

Non-native species that spread rapidly, often outcompeting or preying on native species.

Brown Tree Snake (Guam)

An invasive species responsible for the extinction of many native birds.

Rats on Islands

Invasive rodents that eat bird eggs and disrupt ecosystems.

Mosquitoes in Hawaii

Introduced mosquitoes spread avian malaria, leading to the decline of native birds.

High Extinction Risk on Islands

Island species are vulnerable due to small populations, limited genetic diversity, and lack of defenses against predators.

Habitat Destruction & Climate Change on Islands

Rising sea levels and human development threaten island ecosystems.

Eutrophication

Excess nutrients (often from agriculture) cause algal blooms, leading to oxygen depletion and dead zones.

Oil Spills

Contaminate marine environments, killing wildlife and damaging ecosystems.

Plastic Pollution

Microplastics accumulate in marine organisms, harming food chains.

Coral Bleaching

Stress from rising ocean temperatures causes corals to expel algae, leading to their death.

Ocean Acidification

Increased CO₂ absorption lowers ocean pH, harming shell-building organisms like corals and mollusks.

Sea Level Rise

Floods coastal habitats such as salt marshes and mangrove forests.

Bottom Trawling

A destructive fishing method that damages seafloor ecosystems and coral reefs.