Aquatic Biomes Notes

Aquatic Biomes: A Tour of Aquatic Biomes

Learning Objectives

  • Enduring Understanding ER-1: Ecosystems are the result of biotic and abiotic interactions.

  • Learning Objective ER-1.C: Describe the global distribution and principal environmental aspects of aquatic biomes.

Essential Knowledge

  • ERT-1.C.1: Freshwater biomes include streams, rivers, ponds, and lakes. These freshwater biomes are a vital resource for drinking water.

  • ERT-1.C.2: Marine biomes include oceans, coral reefs, marshland, and estuaries. Algae in marine biomes supply a large portion of the Earth's oxygen and take in carbon dioxide from the atmosphere.

  • ERT-1.C.3: The global distribution of nonmineral marine natural resources, such as different types of fish, varies due to salinity, depth, turbidity, nutrient availability, and temperature.

Human Impacts on Ecosystems

Enduring Understanding STB-3

  • Human activities, including the use of resources, have physical, chemical, and biological consequences for ecosystems.

Human Impacts on Wetlands and Mangroves

  • Learning Objective STB-3.B: Describe the impacts of human activities on aquatic ecosystems.

Essential Knowledge

  • STB-3.B.1: Organisms have a range of tolerance for various pollutants; outside of this range, they may experience stress, limited growth, reduced reproduction, and death.

  • STB-3.B.2: Coral reefs suffer damage due to various factors, including increasing ocean temperature, sediment runoff, and destructive fishing practices.

  • STB-3.B.3: Oil spills in marine waters can lead to the death of organisms; oil affects seabirds and marine mammals.

  • STB-3.B.4: Oil washing up on beaches can have economic consequences for fishing and tourism industries.

Impacts of Human Activity on Wetlands and Mangroves

  • Learning Objective STB-3.E: Describe the impacts of human activity on wetlands and mangroves.

Essential Knowledge

  • STB-3.E.1: Wetlands are areas where water covers the soil, either part or all of the time.

  • STB-3.E.2: Wetlands provide numerous ecological services including water purification, flood protection, filtration, and habitat.

  • STB-3.E.3: Threats include commercial development, dam construction, overfishing, and agricultural and industrial pollutants.

Vocabulary

  • Marine, estuaries, oceans, coastal wetlands, intertidal zone, open ocean, benthos, hydrothermal vents, coral reefs, mangrove forests, salt lakes/inland seas, freshwater, ponds and lakes, rivers and streams, inland wetlands, tides, biological carbon pump, marine snow, coral bleaching, ocean acidification, oligotrophic, mesotrophic, eutrophic, peat.

Additional Insights on Aquatic Biomes

  • Aquatic biomes, also referred to as aquatic life zones, are similarly affected by climatic and abiotic factors:

    • Salinity

    • Temperature

    • Sunlight

    • Turbidity (cloudiness)

    • Depth

    • Nutrient availability

    • Currents

Distinctions between Major Aquatic Biomes

  • Freshwater Biomes (salinity < 1%):

    • Ponds and lakes

    • Rivers and streams

    • Inland wetlands

  • Marine Biomes (saltwater, ~3 to 3.5% salinity):

    • Estuaries (typically brackish)

    • Oceans and their bays

    • Open ocean divided into various zones

    • Coastal wetlands (often brackish)

    • Coastal zone (shorelines)

    • Intertidal zone

    • Coral reefs

    • Mangrove forests (often brackish)

    • Salt lakes/inland seas, which may exceed 3.5% salinity

Productivity in Aquatic Ecosystems

  • NPP (Net Primary Productivity) by Biome Type: Performance measured based on the unit area, area covered, and total NPP.

  • NPP varies greatly across biomes, with coral reefs having the highest, followed by wetlands, and decreases in other zones.

Intertidal Zone Characteristics

  • Phenomenon: Area along the coast that exists above water level at low tide and below during high tide. The tidal movement varies daily due to the gravitational pull of the moon and sun.

  • Environmental Variability: Conditions fluctuate significantly due to temperature variations and salinity changes.

Tidal Pools Dynamics

  • Tide pools can experience temperature increases over the low tide period.

  • Nutrient levels are often high in tide pools; however, salinity increases due to evaporation.

  • Dissolved oxygen levels are typically elevated in these environments.

Ecosystem Services of Intertidal Zones

  • Food sources (e.g., fish, shellfish, kelp)

  • Recreational activities (e.g., beaches)

  • Coastal protection from storm surges

  • Coastal stabilization and prevention of erosion

Threats to the Intertidal Zone

  • Development activities (e.g., harbor construction, dredging)

  • Coastal erosion and sea level rise

  • Solutions include regulations, awareness campaigns, and ecological restoration efforts.

The Open Ocean

  • The largest biome on Earth, comprising about two-thirds of the planet's surface.

  • Characterized by very low NPP, due to nutrient scarcity and limited light in deeper zones.

  • Despite low NPP per square meter, total marine productivity is high.

Zones of the Open Ocean

  • The open ocean comprises various zones:

    • Epipelagic: Upper layer where light penetrates allowing photosynthesis.

    • Mesopelagic: Twilight zone with limited light (1% of incident light).

    • Bathypelagic: Ranges from 1000m to 4000m depth with average temperatures of 4°C.

    • Abyssopelagic: Below 4000m depth, very cold and devoid of light.

    • Hadopelagic: Found in oceanic trenches.

    • Benthic Zone: Ocean or lake bottom, featuring diverse biotic life depending on depth.

Biological Carbon Pump

  • A critical process where carbon from CO2 is converted into organic molecules by marine organisms. These molecules subsequently become part of sediments on the ocean floor.

  • Against the background of atmospheric preferences, this process plays a vital role in regulating global ocean chemistry.

Benthos

  • The community residing at the benthic zone includes varied species adapted to specific depth-related abiotic factors.

  • Nutrience levels differ drastically from low in the deep ocean to high in certain ecosystems such as eutrophic lakes.

  • Ecosystem Services: Include fishing and maintaining habitat biodiversity which sequesters carbon.

Hydrothermal Vents

  • Located along tectonic plate boundaries, these vents are unique ecosystems characterized by extreme environmental conditions conducive to chemosynthesis.

  • Chemosynthetic bacteria constitute the base of the food chain, leading to low NPP but a unique array of organisms, often endemic to these ecosystems.

  • High mineral potential for mining: gold, silver, and other metals.

Coral Reefs

  • Found in warm, shallow waters in tropical and subtropical regions, coral reefs are biodiverse and provide critical habitat for marine species.

  • constituted by coral polyps and symbiotic algae (zooxanthellae) that crucially depend on one another for survival.

  • The health of coral reefs is threatened by invasive species, pollution, and climate change.

  • Coral reefs offer numerous ecological services, including fisheries support, coastline protection, and significant cultural and recreational value.

Coastal Wetlands and Mangrove Forests

  • Mangrove forests represent diverse coastal ecosystems that adapt to saltwater environments.

  • Essential for carbon storage, habitat provision, and coastal protection.

  • Threatened by various human activities including deforestation, development for aquaculture, and pollution.

Salt Lakes and Inland Seas

  • Characterized by elevated salt contents, these unique bodies of water have distinct ecological characteristics and strategies to survive high salinity.

  • They provide limited ecosystem services but have been subjected to human-induced threats such as drainage and pollution.

Ponds and Lakes

  • Classified as lentic ecosystems with varying nutrient levels and biodiversity, they provide numerous ecosystem services from water supply to ecosystem maintenance.

Inland Wetlands

  • Important ecosystems that provide water purification, flood mitigation, and significant contributions to biodiversity, but face severe challenges from human exploitation and climate change.