Marine Ecology 010. Ecology = the study of the interaction of organisms with their environments

  • View
    215

  • Download
    3

Embed Size (px)

Text of Marine Ecology 010. Ecology = the study of the interaction of organisms with their environments

  • Slide 1
  • Marine Ecology 010
  • Slide 2
  • Ecology = the study of the interaction of organisms with their environments.
  • Slide 3
  • It involves understanding biotic and abiotic factors influencing the distribution and abundance of living things.
  • Slide 4
  • Biotic Factors Competitors Disease Predators Food availability Habitat availability Symbiotic relationships Abiotic Factors pH Temperature Weather conditions Water availability Chemical composition of environment nitrates, phosphates, ammonia, O 2, pollution
  • Slide 5
  • The word "ecology" coined from Greek word "oikos", which means "house" or "place to live.
  • Slide 6
  • population growth competition between species symbiotic relationships trophic (=feeding) relationships origin of biological diversity interaction with the physical environment
  • Slide 7
  • Energy Flow & Nutrient Cycle
  • Slide 8
  • Food Chains Artificial devices to illustrate energy flow from one trophic level to another Trophic Levels: groups of organisms that obtain their energy in a similar manner
  • Slide 9
  • Total number of levels in a food chain depends upon locality and number of species Highest trophic levels occupied by adult animals with no predators of their own Secondary Production: total amount of biomass produced in all higher trophic levels Food Chains
  • Slide 10
  • Nutrients Inorganic nutrients incorporated into cells during photosynthesis - e.g. N, P, C, S Cyclic flow in food chains Decomposers release inorganic forms that become available to autotrophs again
  • Slide 11
  • Energy Non-cyclic, unidirectional flow Losses at each transfer from one trophic level to another -Losses as heat from respiration -Inefficiencies in processing Total energy declines from one transfer to another -Limits number of trophic levels
  • Slide 12
  • Energy Flow
  • Slide 13
  • Primary Producer Primary Consumer Secondary Consumer Tertiary Consumer Food Chain Decomposer zooplanktonlarval fish fish fungi Energy Flow through an Ecosystem heat phytoplankton sun water Nutrients
  • Slide 14
  • Transfer Efficiencies Efficiency of energy transfer called transfer efficiency Units are energy or biomass E t = P t P t-1 P t = annual production at level t P t-1 = annual production at t-1
  • Slide 15
  • Transfer Efficiency Example Net primary production = 150 g C/m 2 /yr Herbivorous copepod production = 25 g C/m 2 /yr Typical transfer efficiency ranges *Level 1-2 ~20% *Levels 2-3, : ~10% E t = P t P t-1 = P copepods P phytoplankton = 25 = 0.17 150
  • Slide 16
  • Primary producers Tertiary consumers Secondary consumers Primary consumers 1,000 J 10% efficiency Deposit feeders, filter feeders, grazers 1,000,000 J sunlight 10,000 J algae, seagrass, cyanobacteria, phytoplankton 100 J 1 st order carnivores 10 J 2 nd order carnivores
  • Slide 17
  • Feces Growth Cellular Respiration
  • Slide 18
  • Food Webs Food chains dont exist in real ecosystems Almost all organisms are eaten by more than one predator Food webs reflect these multiple and shifting interactions
  • Slide 19
  • Antarctic Food Web
  • Slide 20
  • Some Feeding Types Many species dont fit into convenient categories Algal Grazers and Browsers Suspension Feeding Filter Feeding Deposit Feeding Benthic Animal Predators Plankton Pickers Corallivores Piscivores Omnivores Detritivores Scavengers Parasites Cannibals Ontogenetic dietary shifts
  • Slide 21
  • Recycling: The Microbial Loop All organisms leak and excrete dissolved organic carbon (DOC) Bacteria can utilize DOC Bacteria abundant in the euphotic zone (~5 million/ml) Numbers controlled by grazing due to nanoplankton Increases food web efficiency
  • Slide 22
  • Solar Energy Microbial Loop CO 2 nutrients Phytoplankton Herbivores Planktivores Piscivores DOC Bacteria Nanoplankton (protozoans)
  • Slide 23
  • Keystone Species A species whose presence in the community exerts a significant influence on the structure of that community.
  • Slide 24
  • Keystone predator hypothesis - predation by certain keystone predators is important in maintaining community diversity.
  • Slide 25
  • Paines study on Pisaster and blue mussels
  • Slide 26
  • Kelp Forests Keystone Species
  • Slide 27
  • Slide 28
  • Algal turf farming by the Pacific Gregory (Stegastes fasciolatus)
  • Slide 29
  • An Ecological Mystery
  • Slide 30
  • Long-term study of sea otter populations along the Aleutians and Western Alaska 1970s: sea otter populations healthy and expanding 1990s: some populations of sea otters were declining Possibly due to migration rather than mortality 1993: 800km area in Aleutians surveyed -Sea otter population reduced by 50%
  • Slide 31
  • Vanishing Sea Otters 1997: surveys repeated Sea otter populations had declines by 90% - 1970: ~53,000 sea otters in survey area - 1997: ~6,000 sea otters Why? - Reproductive failure? - Starvation, pollution disease?
  • Slide 32
  • Cause of the Decline 1991: one researcher observed an orca eating a sea otter Sea lions and seals are normal prey for orcas Clam Lagoon inaccessible to orcas- no decline Decline in usual prey led to a switch to sea otters As few as 4 orcas feeding on otters could account on the impact - Single orca could consume 1,825 otters/year
  • Slide 33
  • Slide 34
  • Slide 35
  • Ecological Succession The progressive change in the species composition of an ecosystem.
  • Slide 36
  • Ecological Succession Climax Stage New Bare Substrate Colonizing Stage Successionist Stage
  • Slide 37
  • PRIMARY SECONDARY b Growth occurs on newly exposed surfaces where no soil exists b Ex. Surfaces of volcanic eruptions b Growth occurring after a disturbance changes a community without removing the soil 2 types of succession
  • Slide 38
  • For example, new land created by a volcanic eruption is colonized by various living organisms
  • Slide 39
  • Disturbances responsible can include cleared and plowed land, burned woodlands
  • Slide 40
  • Mount St. Helens prior 1980
  • Slide 41
  • Mount St. Helens May 18, 1980 Sep. 24, 1980
  • Slide 42
  • Mount St. Helens Fireweed 1980 after eruption 2004 2012
  • Slide 43
  • Hanauma Bay Tuff Ring (shield volcano) Succession after Volcanic Eruption What organisms would appear first? How do organisms arrive, i.e., methods for dispersal? Volcanic eruption creates sterile environment
  • Slide 44
  • Mechanisms of Succession Facilitation Inhibition Tolerance Early species improve habitat. Ex. Early marine colonists provide a substrate conducive for settling of later arriving species. As resources become scarce due to depletion and competition, species capable of tolerating the lowest resource levels will survive. Competition for space, nutrients and light; allopathic chemicals. First arrivals take precedence.
  • Slide 45
  • r & K Selected Species Pioneer species- 1st species to colonize a newly disturbed area r selected Late successional species K selected low competitive ability short life span high growth rate higher maternal investment per offspring low reproductive output high reproductive output slow growth rate long life span high competitive ability r & K refer to parameters in logistic growth equation
  • Slide 46
  • Ecological Succession on a Coral Reef
  • Slide 47
  • Successional Models and their Impacts b Case 1: No Disturbance (Competitive Exclusion Model) b Case 2: Occasional Strong Disturbance (Intermediate Disturbance Model) b Case 3: Constant Strong Disturbance (Colonial Model)
  • Slide 48
  • Case 1: No Disturbance (Competitive Exclusion Model) As the reef becomes complex, organisms compete for space. Dominant organism outcompetes other species. Occurs in stable environments. Results in low species diversity. Highly protected patch reefs within lagoons or protected bays Deeper water
  • Slide 49
  • Case 2: Occasional Strong Disturbance (Intermediate Disturbance Model) Storms and hurricanes allow for other species to move in Dominant species would not be allowed to reach competitive exclusion After each disturbance have a recovery period Area of high diversity
  • Slide 50
  • Case 3: Constant Strong Disturbance (Colonial Model) Constant exposure to disturbance Shallow environment High turnover of species r-selected species
  • Slide 51
  • Reef Case 3 Case 2 Case 1 Deep reef slope Reef slope beneath reef crest Near reef crest
  • Slide 52
  • Ecological Succession on a Coral Reef The Big Island
  • Slide 53
  • Ecological Succession on a Coral Reef
  • Slide 54
  • Slide 55
  • Slide 56

Related documents