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Chapter 8
Temperate Coastal SeasTemperate Coastal Seas
More than 90% of marine animals are benthic, living in close association with the seafloor, at the interface with the overlying water, dependent on the characteristics of each and the exchange of substances between the two.
Seafloor Characteristics
The composition of the sea bottom is determined by: plankton, wastes, and detritus
the activities of organisms that live there
the energy in waves in shallow water
the energy in currents in shallow water
Seafloor Characteristics
Fig. 8.1 In coves and bays, refraction of advancing ocean waves
spreads out the wave crests (and their energies) and concentrates
them on headlands and other projecting coastal features.
Seafloor Characteristics
Fig. 8.2 Particle size ranges for some common sources of marine sediments. Biogenic particles are shown in blue and terrigenous
particles in tan.
Animal–Sediment Relationships
Benthic animals are either:
epifaunal, living on the sediment, or
infaunal, living within the sediment.
Animal–Sediment Relationships
Fig. 8.3 Variations in the average number of species of several
bottom invertebrate groups from equal-sized coastal areas in
different latitudes.
Adapted from G. Thorson. Treatise on Marine Ecology and Paleoecology. Vol. I., Ecology. Geological Society of America, 1957.
Animal–Sediment Relationships
Fig. 8.4 Sandstone erosion pits created by the rasping actions of
small chitons.
Animal–Sediment Relationships
Suspension and filter
feeders obtain their food from passing waters
Fig. 8.5 Barnacle, Balanus, with its feathery filtering appendages extended.
© Sanamyan/Alamy Images
Animal–Sediment Relationships
Fig. 8.6 A phalanx of sea stars, Pisaster, crops a
bed of mussels.
Photo by Dave Cowles, Rosario Marine Invertebrates website http://rosario.wallawalla.edu/inverts
Animal–Sediment Relationships
Fig. 8.7 A large snail grazing on seaweed.
© Christopher Poliquin/ShutterStock, Inc.
Larval Dispersal
About 75% of slow-moving, sedentary, or attached animals extend their geographic range via broadcast spawning of eggs and sperm that will result in larvae that are temporarily planktonic (or meroplanktonic).
Larval Dispersal
Fig. 8.8 Meroplanktonic larval forms (top) and adult forms (bottom) of some common benthic animals: (a) polychaete worm,
(b) sea urchin, (c) crab, and (d) snail.
Larval Dispersal
Fig. 8.9 Typical duration of planktonic existence for four common groups of
marine benthic invertebrates.
Adapted from G. Thorson. Oceanography (1961): 455-474.
Larval Dispersal
Many factors influence meroplanktonic larvae to settle on the seafloor and metamorphose into juveniles:
• bottom type• bottom texture• chemical attractants• current speeds• sounds• light• presence of conspecific adults
Larval Dispersal
Fig. 8.10 Several major environmental factors that influence the
selection of suitable bottom types by planktonic larvae.
Larval Dispersal
Fig. 8.11 Generalized development pattern for planktonic larvae, illustrating available options in response to food, substrate, or other
environmental cues.
Larval Dispersal
Fig. 8.2 A scanning electron micrograph of a sea urchin egg with numerous sperm cells.
© Dr. David Phillips/Visuals Unlimited
Intertidal Communities
Daily fluctuations in tidal heights result in an intertidal, or littoral, zone forming on all shorelines, regardless of slope or texture.
This zone is inhabited by species of marine origin that experience, and somehow tolerate, physiological stress during periods of low tide.
Intertidal Communities
Fig. 8.14 An infrared aerial photograph of a portion of the Oregon coast with protected coves, exposed headlands, sandy beaches, and offshore rocky reefs. Note the complex refraction
of surface waves around the offshore reefs.
Courtesy U.S. Geological Survey
Intertidal Communities
Fig. 8.15 (a) Young red mangroves colonize a tropical shoreline. (b) Their network of prop roots traps sediment and detritus.
© FloridaStock/ShutterStock, Inc.
Courtesy of OAR/National Undersea Research Program
(NURP)/NOAA
Intertidal Communities
Fig. 8.16 The relative force of breaking waves over a range of wave heights for several
different intertidal animals.
Adapted from Denny, M. W. Limnology and Oceanography 30 (1985): 1171-1187.
Intertidal Communities
Rocky Shores Distance from low water is correlated with
variations in physical and biological stresses, resulting in distinct horizontal bands of zonation.
Intertidal Communities
Fig. 8.17 Magnified cross-section of a lichen with algae cells (dark spots) embedded in fungal
filaments.
Fig. 8.18 Snails and limpets grazing on sparsely distributed algae growing along the edge of a tidal
pool.
Rocky Shores
© Wildlife Pictures/age fotostock
Intertidal Communities
Rocky Shores The upper intertidal of rocky shorelines
hosts organisms that suffer from frequent desiccation and punctuated food supplies.
Fig. 8.19 Stunted acorn barnacles, Chthamalus, survive in the shallow depression of carved
letters.
Intertidal Communities
Fig. 8.20 Planktonic and early benthic stages of the barnacle Balanus:
(a) nauplius stage, (b) cypris stage, and (c) early benthic stage.
Rocky Shores
Intertidal Communities
Fig. 8.21 The limiting effects of desiccation and competition on the
vertical distribution of two species of intertidal barnacles, Chthamalus (blue
bars) and Balanus (green bars).
Adapted from Connell, J. H. Ecology 42 (1961): 710-723.
Intertidal Communities
Rocky Shores The middle intertidal is more densely
populated with species more troubled by competition for food and space than physical limitations of the environment.
Intertidal Communities
Rocky Shores
Fig. 8.22 The aggregate sea anemone, Anthopleura elegantissima. Exposed individuals (upper right) have
retracted their tentacles to avoid dessication.
© Danita Delimont/Alamy Images
Intertidal Communities
Fig. 8.23 Close-up view of mussels, Mytilus, attached to rocks in the middle intertidal.
Fig. 8.24 algal species exposed during low tides use thickened cell walls to prevent water loss.
© Carsten Medom Madsen/ShutterStock, Inc.
Intertidal Communities
Fig. 8.25 Tightly packed barnacles compete for space along the intertidal.
Photo by Dave Cowles, Rosario Marine Invertebrates website http://rosario.wallawalla.edu/inverts
Intertidal Communities
Fig. 8.26 Sea stars, Pisaster, aggregating
near the low tide line to avoid dessication.
© Charles A. Blakeslee/age fotostock
Intertidal Communities
Fig. 8.27 General pattern of succession through time on temperate rocky shores. The blue curve indicates a relative biomass.
Intertidal Communities
Rocky Shores The lower intertidal hosts a diversified assemblage
of plants and animals that are exposed to air for only a short period of time each day.
Fig. 8.28 Surf grass covers rocks and helps to keep intertidal organisms moist during low tide.
© Weldon Schloneger/ShutterStock, Inc.
Intertidal Communities
Fig. 8.29 The green anemone,
Anthopleura xanthogrammica.
Fig. 8.30 An eolid nudibranch with long finger-like
cerata projecting from its dorsal surface.
© Weldon Schloneger/ShutterStock, Inc.
© Kerry L. Werry/ShutterStock, Inc.
Intertidal Communities
Fig. 8.31 A scallop flaps its valves (shells) vigorously to jet away from a predatory sea star.
© Marevision/age fotostock
Intertidal Communities
Fig. 8.32 Vertical zonation patterns on a 3-m-high rock on
the coast of Oregon.
Intertidal Communities
Sandy Beaches Sandy beaches and muddy shores are
depositional environments characterized by deposits of unconsolidated sediments and accumulations of detritus.
Intertidal Communities: Sandy Beaches
Fig. 8.33 Sandy beach zonation along the East Coast of the United States. The species change rapidly from the portion permanently under water at left to the dry
part of the beach above high tide at the right.
Sea cucumber: Courtesy of Dr. James P. McVey/NOAA Sea Grant Program; Olive shell: Courtesy of Image*After; Blue crab: © APaterson/ShutterStock, Inc.; Flounder: Courtesy of NW Fisheries Science Center/NOAA; Sand dollar and Cockle: Photodisc; Clam: Courtesy of Dr. Roger Mann, VIMS/NOAA; Bristle worm and Land crab : Courtesy of NOAA; Amphipod: Courtesy of M. Quigley, GLERL/NOAA, Great Lakes Environmental Research Laboratory.
Intertidal Communities: Sandy Beaches
Fig. 8.34 Coiled fecal casting of the lugworm, Arenicola.© Ismael Montero Verdu/ShutterStock, Inc.
Intertidal Communities: Sandy Beaches
Fig. 8.35 A sand crab, Emerita, backing into the sand in preparation for feeding.
© Stan Elems/Visuals Unlimited
Intertidal Communities: Sandy Beaches
Fig. 8.36 A few examples of the interstitial fauna of sandy beaches. Each is of a different phylum, yet all exhibit the small size and worm-shaped body characteristic of meiofauna: (a) polychaete, Psammodrilus; (b) a copepod, Cylindropsyllis; (c) a
gastrotrich, Urodasys; and (d) a hydra Halammohyra.
Adapted from S. K. Eltringham. Life in the Mud and Sand. Crane, Russak, 1972.
Intertidal Communities: Sandy Beaches
Fig. 8.37 Grunion, Leuresthes, spawning in the sands of a southern California beach.
Males coil around females that dig themselves into the sand to
deposit their eggs.
© Visual&Written SL/Alamy Images
Intertidal Communities: Sandy Beaches
Fig. 8.38 Predicted tide heights for a 3-week period at San Diego, California. Spring tides appropriate for grunion spawning occur on days 6, 7, and 8 (pointers at left). Nine and 10 days later, the next set of spring tides (pointers at right) wash the eggs from the sand, and
they hatch. Shaded portions indicate night hours.
Intertidal Communities
Oiled Beaches Because oil is less dense than seawater,
when it is spilled (intentionally or not), most of it ends up in intertidal zones.
Intertidal Communities
Oiled Beaches
Fig. 8.39 An oil-soaked bird struggles to survive after an oil spill.Photo courtesy of the Exxon Valdez Oil Spill Trustee Council
Intertidal Communities
Oiled Beaches
Fig. 8.40 Scores of dead birds litter a beach after an oil spill.Photo courtesy of the Exxon Valdez Oil Spill Trustee Council
Intertidal Communities
Oiled Beaches
Fig. 8.41 Workers use high-pressure hot water to clean an
oiled beach.
Photo courtesy of the Exxon Valdez Oil Spill Trustee Council
Shallow Subtidal Communities
Fig. 8.42 A series of soft-bottom benthic communities found at different depths in Danish seas, including bivalve mollusks (1, 2, 3, 7, 8, 9, 10, 19), polychaete worms (6, 15), scaphopod mollusks (16), ophiuriod
echinoderms (12,13), echinoid echinoderms (14), and arthropod crustaceans (18).
Shallow Subtidal Communities
Fig. 8.43 Diagram showing the close
similarity in composition of soft-bottom communities in the northeast Pacific
and the northeast Atlantic.
Adapted from Adapted from G. Thorson. Treatise on Marine Ecology and Paleoecology. Vol. I., Ecology. Geological Society of America, 1957.
Shallow Subtidal Communities
Fig. 8.44 Several species of kelp-community fishes sheltering near giant kelp, Macrocystis.
© Galina Barskaya/ShutterStock, Inc.
Shallow Subtidal Communities
Below the effects of waves and tides, kelp communities dominate in temperate areas.
Fig. 8.45 General structure of a West Coast kelp forest, with a complex understory of plants beneath the dominant Macrocystis or Nereocystis.
Shallow Subtidal Communities
Fig. 8.46 Trophic relationships of some dominant members of a southern California kelp community.
Shallow Subtidal Communities
Fig. 8.47 Trophic relationships of the common
members of a New England kelp community.
Shallow Subtidal Communities
Fig. 8.48 Extent of areas changed or degraded by four major sewage
outfalls in the California Bight, 1978-1979.
Data from A. J. Mearns. Marine Environmental Pollution. Elsevier, 1981.
Shallow Subtidal Communities
Fig. 8.49 Graphs showing the reduction in discharged total suspended solids (TSS) for the past two decades at the four major sewage outfalls in the California
Bight.Data from Steinberger and Schiff, 2002.