Biological Oceanography

Biological Oceanography

  • Connection between physical, chemical aspects and marine biology.

  • Key Concept: Biological components (like nutrients) are pivotal for marine life.

Nutritional Requirements for Marine Organisms

  • All organisms require food to live; nutrients are essential.

  • Essential nutrients include electrolytes, carbohydrates, fats, and proteins.

    • Electrolytes: Magnesium, calcium, and sulfate from seawater contribute to salinity.

    • Dissolved Organic Carbon (DOC): Includes dissolved amino acids, important for building proteins.

      • Example: Amino acids from biological sources suggest organic processes.

    • Nutrients: Nitrogen and phosphorus serve as fertilizers in marine ecosystems, critical for growth.

      • Nitrogen is a fundamental building block of proteins.

      • Other important minerals: Iron and various trace elements.

Types of Organic Carbon in the Ocean

  • Particulate Organic Carbon (POC): Solid organic matter such as decaying organisms.

    • Distinction between dissolved ions and visible solid particles in water.

  • Nutritional gain for marine animals typically comes from consuming other organisms rather than absorbing directly from water.

Trophic Levels: Nutrient Transfer in Ocean Food Web

  • Phytoplankton: Base of the marine food web; photosynthetic and absorb nutrients directly.

  • Zooplankton: Consume phytoplankton, transferring energy and nutrients upward in the food chain.

  • Largest animals, like whales, rely on small organisms (e.g., krill) as primary food sources.

Role of Krill in Marine Ecosystems

  • Krill as a fundamental link in the food web—feeding on phytoplankton and being prey for larger marine animals.

    • Importance: Essential for nutrient cycling and carbon absorption.

  • Carbon Capture: Krill help draw down atmospheric carbon, potentially mitigating climate change impacts.

    • Example: Blue whales depend almost entirely on krill for nourishment and play a role in carbon sequestration.

Research and Environmental Impact

  • The health of krill populations is essential for global carbon cycling and climate regulation.

  • Climate change poses risks to krill and consequently to the entire marine food web.

    • Research endeavors utilize new technology to monitor krill populations from space.

  • Notable statistic: Total weight of krill approximates 400 million tons, similar to the entire human population's weight.