Who, What, When, Where, Why, and How of Marine Ecology

1. Who, What, When, Where, Why, and How of Marine Ecology • Who studies marine-life habitat, populations, and interactions among organisms and the surrounding environment including their abiotic and biotic factors? • What factors contribute to the distribution of marine organisms in their environment? • When do temperature changes affect communities? • Where is the benthic zone? • Why are trophic pyramids important to Marine Ecologists? • How are heterotrophs related to autotrophs?

2. 0 Chapter 2 Fundamentals of Ecology Karleskint Turner Small

3. Marine Ecology • Marine Ecology is the scientific study of marine-life habitat, populations, and interactions among organisms and the surrounding environment including their • abiotic factors - non-living physical and chemical factors that affect the ability of organisms to survive and reproduce and • biotic factors - living things or the materials that directly or indirectly affect an organism in its environment

4. Study of Ecology 0 • Ecology • from the Greek word oikos meaning “home” • Environment • biotic factors (living) • abiotic factors (non-living) • Habitat: where an organisms lives • Ecosystems • composed of living organisms and their non-living environment

6. Study of Ecology 0 • The study of organisms interacting with one another and their environment. This entails: • biological (biotic) factors • environmental (abiotic) factors • the organism’s behavior • Niche: an organism’s environmental role • Its “job” in the environment

7. Homeostasis and Distribution of Marine Organisms 0 • Maintaining homeostasis • changes in external environment • internal adjustments to maintain a stable internal environment • optimal range • For example, we have optimum temperature (98.6), pH, etc. • zones of intolerance

9. Characteristics of the Physical Environment that Affect Organism Distribution 0 • Organisms might be limited as to where there is sunlight: • For photosynthesis • For vision • Organisms might be limited to location by temperature • ectotherms • endotherms

10. Characteristics of the Physical Environment that Affect Organism Distribution 0 • Organisms might be limited to where they can live by salinity • Some can withstand higher salinity than others

12. Characteristics of the Physical Environment that Affect Organism Distribution 0 • Some organisms are limited to location by pressure • 760 mm Hg or 1 atmosphere at sea level • increases 1 atmosphere for every 10 meters below sea level • Deep sea animals are adapted to living at high pressure

13. Characteristics of the Physical Environment that Affect Organism Distribution 0 • Metabolic requirements • nutrients and limiting nutrients • oxygen as a requirement for cell respiration • Anaerobic organisms – don’t need oxygen • aerobic organisms – do need oxygen • Excess nutrients can result in eutrophication and algal bloom • Metabolic wastes • carbon dioxide is a common byproduct of metabolism

14. As a review: • Physical characteristics of the environment will effect organism distribution • Temperature • pH • Salinity • Sunlight • Pressure • Nutrient availability (oxygen, nitrates, phosphates, etc)

15. Individuals • Population – group of individuals of same species • Community – different species living together • Ecosystem – community plus abiotic factors

16. Populations 0 • A group of the same species that occupies a specified area • Geographic range • For example, the lagoon, open ocean, deep sea, etc. • Population size

17. Distribution of Organisms in a Population 0 • Population density (abundance) • Dispersion • clumped • uniform • random

18. Changes in Population Size 0 • Can occur through: • reproduction • immigration • death • emigration • Can be affected by: • survivorship • life history • opportunistic and equilibrium species

19. Population Growth 0 • Many ways a population can increase in size, depending on the carrying capacity of the environment • exponential/logarithmic growth • logistic growth

20. Exponential growth Logistic growth

21. Communities 0 • Composed of populations of different species that occupy one habitat at the same time • Niche: what an organism does in its environment • fundamental niche • What all that species could do in the environment • realized niche • Species are going to be limited by other species in the area that might have similar niches

22. Communities 0 • Biological environment • competition • may be interspecific or intraspecific • may result in competitive exclusion • resource partitioning allows organisms to share a resource • predator-prey relationships • balance of abundance of prey vs. predators • keystone predators

23. Communities 0 • Symbiosis: living together • mutualism – both organisms benefit • commensalism – one organism benefits, the other is nether harmed nor benefited • parasitism – one organism benefits, the other is harmed

24. Ecosystems: Basic Units of the Biosphere • Energy flow through ecosystems • Producers = Autotrophs • auto = self, troph = feed • Convert energy from the sun and harness it into organic molecules that will make their way up the food chain • Photosynthetic producers – some bacteria, algae, plants • Majority of primary producers on the planet • Chemosynthetic producers – some bacteria that live in hydrothermal vents • Do not use energy from sun, instead use energy from inorganic molecules being released from hydrothermal vents at bottom of the ocean

26. Ecosystems: Basic Units of the Biosphere • Consumers = Heterotrophs • hetero = other, troph = feed • Different levels of consumers: • first-order consumers (herbivores) • second- and third-order consumers (omnivores and carnivores) • detrivores • decomposers • Food chains and food webs

29. Ecosystems: Basic Units of the Biosphere • Trophic levels • number of levels is limited because only a fraction of the energy at one level passes to the next level • ecological efficiency • ten percent rule • trophic pyramids • as energy passed on decreases, so does the number of organisms that can be supported

32. Biogeochemical Cycles • Hydrologic cycle • water is lost through evaporation • carried north and south from equator • carried west to east within each hemisphere • returned through precipitation and runoff

34. Biogeochemical Cycles • Carbon cycle • Cellular respiration • carbon released from organisms through respiration and decomposition • That’s why we breathe out CO2 • Photosynthesis • The carbon in CO2 isrecycled by photosynthetic producers • carbon is used in shells, corals and skeletons as part of calcium carbonate • fossil fuels, when burned, release CO2 back into atmosphere

36. Biogeochemical Cycles • Nitrogen cycle • fixation of atmospheric nitrogen by microorganisms that have symbiotic relationship with plants • Producers (plants) use nitrogen to synthesize amino acids to form proteins • Other organisms eat those producers, to form their own proteins, nitrogen makes it’s way up the food chain • bacteria recycle nitrogen from wastes and decomposing, dead organisms

38. Biosphere • Includes all of earth’s communities and ecosystems • Examples of ecosystems: • estuaries • salt marshes • mangrove swamps • rocky and sandy shores • kelp forests • coral reefs • open ocean

39. Distribution of Marine Communities • Pelagic division • Zones according to location to land: • neritic zone (nearshore) and pelagic zone (open ocean) • Zones according to light penetration: • photic zone (light), disphotic zone (little light), and aphotic zone (no light, majority of the ocean) • Majority of the biomass of ocean is in photic zone • Organisms that live in the pelagic: • Plankton (organisms that float) and nekton (organisms that swim) • Benthic division • Bottom sediment area: • shelf zone, bathyal zone, abyssal zone, and hadal zone • Organisms that live in the benthic zone are divided into: • Epifauna (organisms that live on top of sediment) and infauna (organisms that live in the sediment)