Download
1 / 25
250 likes | 386 Views
BIOLOGY 457/657 PHYSIOLOGY OF MARINE & ESTUARINE ANIMALS. January 28, 2004 Introduction to the Course Marine & Estuarine Environments. COMPARATIVE PHYSIOLOGY Comparative physiology is the study of physiological mechanisms used by a diversity of species. Advantages of the comparative approach:
E N D
BIOLOGY 457/657PHYSIOLOGY OF MARINE & ESTUARINE ANIMALS January 28, 2004 Introduction to the Course Marine & Estuarine Environments
COMPARATIVE PHYSIOLOGYComparative physiology is the study of physiological mechanisms used by a diversity of species Advantages of the comparative approach: • Provides insight into common solutions to common problems • Helps solve problems that cannot be dealt with in humans • Provides ideas concerning how animals solve important problems • Can suggest or test new medical treatments • Can work with ecology to explain how communities are structured • Can help find strategies for managing environmental stress • Is fun for its own sake, giving an appreciation of the natural world Since almost all types of animals exist in the oceans, much of comparative physiology involves the study of marine, intertidal, or estuarine animals.
THE MARINE ENVIRONMENT The marine environment is a continuous system, with internal discrete regions (71% of earth’s surface) Includes numerous special phenomena: currents, tides, upwelling, gyres Has benthic and pelagic regions, each with vertical zonation
Benthic Environments Supralittoral (above high water) Littoral (intertidal) Sublittoral (to edge of the continental shelf, ~200 m) Bathyal (to bottom of the continental slope, ~4000 m) Abyssal (on the abyssal plain, to ~5500 m) Hadal (to the bottoms of deep trenches, ~10,000 m)
Pelagic Environments Neritic (overlying the continental shelf) Oceanic (beyond the continental shelf) Epipelagic, or Photic(to ~200 m) Mesopelagic (to ~1000 m) Bathypelagic (to ~4000 m) Abyssopelagic (to ~6000 m) Hadalpelagic (in deep trenches, ~10,000 m)
Abiotic Features of Marine Environments Chemical factors: Seawater is a solution of virtually every element and many chemical compounds. Salinity - 3.5% or 35o/oo. Salt content is biologically critical, as it exerts chemical, ionic, and osmotic effects on organisms. Gases – O2, N2, CO2, H2S Physical factors: Temperature – ranges in the ocean from <–2° to >30°C. Pressure – increases by 1 atm per 10m depth. Tides – most important in littoral and upper sublittoral zones. Light – varies in intensity, spectrum, and duration. Overall, abiotic factors are fairly restricted in range at a given location, but may vary substantially between seasons or between oceanic regions
TIDESHHW“High high water”LHW “Low high water”MSL“Mean sea level”HLW“High low water”LLW “Low low water”MLLW “Mean low low water”MLW “Mean low water”
TIDES Gravitational effects of the sun & moon.The Spring:Neap cycle
THE INTERTIDAL ENVIRONMENT Major Types (“Hard-bottom” vs “Soft-bottom”) • Rocky Intertidal(e.g. coast of California, Maine) • Sandy Beach (e.g. Assateague Island) • Mud-Flat (e.g. salt marshes) General Characteristics • Tendency for extreme variation (T,S, 02, H2O) • Tendency for vertical zonation from ELWS to EHWS • Tendency for stress caused by waves and currents
THE ESTUARINE ENVIRONMENT Estuary: a semi-enclosed coastal body of water that has a full connection with the open sea and within which sea water is measurably diluted with fresh water derived from land drainage (D. Pritchard). Classes of Estuaries: Drowned River Valley – caused by changes in sea level; generally very short-lived (Chesapeake Bay) Tectonically-Produced Estuary – subsidence, faults (San Francisco Bay) Bar-Built Estuary – coastal lagoons, sounds (Pamlico Sound) Fjords – glacial valleys (New Zealand, Alaska, Norway)
ESTUARINE CHARACTERISTICS The environment is highly variable, with extreme variation in salinity and temperature. Oxygen stress is also common. Currents move organisms along the estuary. Sediments are soft and frequently anoxic.
ESTUARINE SPECIALIST SPECIES The biota of estuaries are LOW in species diversity and HIGH in individual abundance. Few species can tolerate estuarine stresses, but those that do flourish.
