temperate coastal seas

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


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.


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.


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.


Fig. 8.4 Sandstone erosion pits created by the rasping actions of

small chitons.


Suspension and filter

feeders obtain their food from passing waters

Fig. 8.5 Barnacle, Balanus, with its feathery filtering appendages extended.

© Sanamyan/Alamy Images


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


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.


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


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


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.


Rocky Shores Distance from low water is correlated with

variations in physical and biological stresses, resulting in distinct horizontal bands of zonation.


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


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.


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


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.


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.


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


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.


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


Fig. 8.26 Sea stars, Pisaster, aggregating

near the low tide line to avoid dessication.

© Charles A. Blakeslee/age fotostock


Fig. 8.27 General pattern of succession through time on temperate rocky shores. The blue curve indicates a relative biomass.


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.


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.


Fig. 8.31 A scallop flaps its valves (shells) vigorously to jet away from a predatory sea star.

© Marevision/age fotostock


Fig. 8.32 Vertical zonation patterns on a 3-m-high rock on

the coast of Oregon.


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.


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.


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


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.


Oiled Beaches Because oil is less dense than seawater,

when it is spilled (intentionally or not), most of it ends up in intertidal zones.


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


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


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).


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.


Fig. 8.44 Several species of kelp-community fishes sheltering near giant kelp, Macrocystis.

© Galina Barskaya/ShutterStock, Inc.


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.


Fig. 8.46 Trophic relationships of some dominant members of a southern California kelp community.


Fig. 8.47 Trophic relationships of the common

members of a New England kelp community.


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.


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.

temperate coastal seas

Technology

larval dispersalfig

marine animals

meroplanktonic larval

common benthic animals

meroplanktonic larvae

marine ecology

seafloor characteristicsfig

attached animals