Ecological and biological background for understanding marine systems

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Ecological and biological background for
understanding marine systems

• Dr. Ouida Meier, Marine Biology

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Overview how marine systems tend to work

• Disturbance (intensity, frequency,
  predictability)
• Organisms interactions with other organisms
• Organisms interactions with abiotic environ.
• Physical environment

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Outline

• Ecological Principles
• Larvae and Larval Ecology
• Comparison of Marine and Terrestrial Systems
• Systems Ecology

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Ecological Principles

• Terms and definitions
• Ecology
• Species
• Population
• Community
• Ecosystem

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Ecological Principles

• Terms and definitions (cont.)
• Trophic structure
• Autotroph
• Heterotroph (herbivore, carnivore)
• Decomposer
• Abiotic source of energy, nutrients, water
• Food chain -gt Food web
• Trophic pyramid
• (standing crop, inverted pyramid)

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Ecological Principles

• Biogeochemical cycles
• N, C, P
• Biotic structure of ecosystems
• Niche
• Habitat
• Species dominance, richness, diversity
• Competition, predation, parasitism

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Ecological Principles

• Control and regulation of ecosystems
• Disturbance
• Intermediate disturbance hypothesis (Connell and
  others)
• Intensity
• Frequency
• Predictability

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Larvae and Larval Ecology

• Larvae are the dispersal form of sessile benthic
  invertebrates
• Pelagic (swimming)
• Planktotrophic larvae (plankton-eating)
• Lecithotrophic larvae (egg-eating)
• Direct development (nonpelagic)

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Larvae and Larval Ecology

• Why a particular strategy?
• Potentially a balance of factors
• Energy allocation
• Dispersal
• Settling space (microhabitat availability)
• Adult longevity and competition
• vs. need to produce large numbers of young

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Larvae and Larval Ecology

• Settlement and metamorphosis
• Cues for species can be bacteria, presence of
  adults, host species, food source, crustose
  coralline algae, many others.
• Specialists vs. Generalists
• (K-selected vs. r-selected)

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Comparison of Terrestrial and Marine Ecosystems

• Seawater vs. Air
• Density, viscosity, temperature, gravity, speed
  of sound, electrical resistivity, oxygen
• Filter feeding DOM

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Comparison of Terrestrial and Marine Ecosystems

• Biodiversity
• Taxon Marine Terrestrial Freshwater
• Phyla 32 12 16
• Classes 73 25 33
• Similar latitudinal gradients

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Comparison of Terrestrial and Marine Ecosystems

• In marine systems
• Microscopic autotrophs
• Small herbivores
• Relatively long-lived animals
• Carnivores the majority
• Efficiency of trophic transfer often higher
• Trophic flexibility often greater

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Systems Ecology

• Boundary
• Components
• Inputs
• Outputs
• Currency
• Direct interactions
• Indirect interactions
• Feedback loops / cycling