14 the tidelands rocky shores soft substratum shores marshes mangroves and estuaries l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
14 -The Tidelands Rocky Shores, Soft-Substratum Shores, Marshes, Mangroves, and Estuaries PowerPoint Presentation
Download Presentation
14 -The Tidelands Rocky Shores, Soft-Substratum Shores, Marshes, Mangroves, and Estuaries

Loading in 2 Seconds...

play fullscreen
1 / 93

14 -The Tidelands Rocky Shores, Soft-Substratum Shores, Marshes, Mangroves, and Estuaries - PowerPoint PPT Presentation


  • 222 Views
  • Uploaded on

14 -The Tidelands Rocky Shores, Soft-Substratum Shores, Marshes, Mangroves, and Estuaries. Notes for Marine Biology: Function, Biodiversity, Ecology By Jeffrey S. Levinton. ©Jeffrey S. Levinton 2001. ZONATION -universal feature of rocky shores,

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about '14 -The Tidelands Rocky Shores, Soft-Substratum Shores, Marshes, Mangroves, and Estuaries' - ostinmannual


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
14 the tidelands rocky shores soft substratum shores marshes mangroves and estuaries

14 -The TidelandsRocky Shores, Soft-Substratum Shores, Marshes, Mangroves, and Estuaries

Notes for Marine Biology: Function, Biodiversity, Ecology

By Jeffrey S. Levinton

©Jeffrey S. Levinton 2001

slide2

ZONATION -universal feature of rocky shores,

also true of soft sediments but not as distinct

(3-dimensional nature, owing to presence of

burrowing organisms and others within the

sediment)

slide3

Example of zonation on rocky shore, along a gradient of

wave exposure on a site in the United Kingdom

2 spatial gradients
2 SPATIAL GRADIENTS:
  • Vertical
  • Horizontal - changing wave exposure
vertical gradient
Vertical gradient
  • Heat Stress, Desiccation
  • Gas Exchange - dissolved oxygen
  • Reduced feeding time
  • Wave shock
  • Biological interactions - competition, predation
heat stress desiccation
Heat Stress/Desiccation
  • Varies on small spatial scales
  • Body size, shape are both important - reduction of surface area/volume reduces heat gain and water loss
  • Evaporative cooling and circulation of body fluids aids in reduction of heat loss
  • Well sealed exoskeletons aid in retarding water loss (acorn barnacles, bivalves)
vertical gradients
Vertical Gradients
  • Higher intertidal organisms more resistant to heat and desiccation stress than lower intertidal organisms
vertical gradients 2
Vertical Gradients 2
  • Higher intertidal organisms more resistant to heat and desiccation stress than lower intertidal organisms
  • Higher intertidal animals have less time to feed. Sessile forms therefore grow more slowly than lower intertidal organisms
vertical gradients 3
Vertical Gradients 3
  • Higher intertidal organisms more resistant to heat and desiccation stress than lower intertidal organisms
  • Higher intertidal animals have less time to feed. Sessile forms therefore grow more slowly than lower intertidal organisms
  • Mobile carnivores can feed only at high tide, usually feed more effectively at lower tide levels, which are immersed a greater proportion of the day
oxygen consumption
Oxygen consumption
  • Intertidal animals usually cannot respire at time of low tide
oxygen consumption 2
Oxygen consumption 2
  • Intertidal animals usually cannot respire at time of low tide
  • Respiratory organs (gills of polychaetes, bivalves) must be moist to acquire oxygen, and therefore are usually withdrawn at low tide
oxygen consumption 3
Oxygen consumption 3
  • Intertidal animals usually cannot respire at time of low tide
  • Respiratory organs (gills of polychaetes, bivalves) must be moist to acquire oxygen, and therefore are usually withdrawn at low tide
  • Some animals greatly reduce metabolic rate at time of low tide
oxygen consumption 4
Oxygen consumption 4
  • Intertidal animals usually cannot respire at time of low tide
  • Respiratory organs (gills of polychaetes, bivalves) must be moist to acquire oxygen, and therefore are usually withdrawn at low tide
  • Some animals greatly reduce metabolic rate at time of low tide
  • Some high intertidal animals can respire from air (e.g., some mussels) even at low tide, as long as air is not too dry
slide14

Pacific sand bubbler crab, Scopimera inflata, has membrane

on each leg (shaded green), which exchanges gas from air

into arterial blood

wave shock 1
Wave shock 1
  • Abrasion - particles in suspension scrape delicate structures
wave shock 2
Wave shock 2
  • Abrasion - particles in suspension scrape delicate structures
  • Pressure - hydrostatic pressure of breaking waves can crush compressible structures
wave shock 3
Wave shock 3
  • Abrasion - particles in suspension scrape delicate structures
  • Pressure - hydrostatic pressure of breaking waves can crush compressible structures
  • Drag - impact of water can exert drag, which can pull organisms from their attachments to surfaces, erode particles from beaches and carry organisms from their burrows or living positions
causes of vertical zonation 1
Causes of Vertical Zonation 1
  • Physiological tolerance of different species at different levels of the shore
causes of vertical zonation 2
Causes of Vertical Zonation 2
  • Physiological tolerance of different species at different levels of the shore
  • Larval and adult preference - larvae may settle at time of high tide at high levels, mobile organisms have a series of behavioral responses that keep them at certain levels of shore
causes of vertical zonation 3
Causes of Vertical Zonation 3
  • Physiological tolerance of different species at different levels of the shore
  • Larval and adult preference - larvae may settle at time of high tide at high levels, mobile organisms have a series of behavioral responses that keep them at certain levels of shore
  • Competition - species may be capable of excluding others from certain levels of the shore
causes of vertical zonation 4
Causes of Vertical Zonation 4
  • Physiological tolerance of different species at different levels of the shore
  • Larval and adult preference - larvae may settle at time of high tide at high levels, mobile organisms have a series of behavioral responses that keep them at certain levels of shore
  • Competition - species may be capable of excluding others from certain levels of the shore
  • Predation - mobile predators more effective usually on the lower shore: affects distributions of vulnerable prey species
slide22

A rocky shore in the U.K. At the time of low tide on hot dry days, the

gastropod Nucella lapillus retreats into the crack where it is moist and

cool. Note the areas cleared of mussels adjacent to the cracks.

beaches and wave action
Beaches and Wave Action
  • Exposed beaches - strong erosion and sediment transport
  • Difficult environment for macrobenthos to survive and maintain living position
  • Swash riding - means of moving up and down with rising and falling tide - maintain position in wet but relatively non-eroded tidal level
slide25

The mole crab, Emerita talpoida, burrowing into

an exposed beach in North Carolina

interspecific interactions and zonation
Interspecific Interactions and Zonation
  • Why are there vertical zones, with dominance often of single sessile species within a zone?
interspecific interactions and zonation 2
Interspecific Interactions and Zonation 2
  • Why are there vertical zones, with dominance often of single sessile species within a zone?
  • Possible explanations: (1) Differences in tolerance of species at different tidal heights (2) Competitive interactions (3) other factors
investigation by field manipulation experiments
Investigation by Field Manipulation Experiments
  • Classic experiments of Joseph Connell
  • Studied factors controlling vertical zonation by selective inclusion and exclusion of hypothesized interacting species
rocky shores of scotland key species in connell s study
Rocky Shores of Scotland - Key Species in Connell’s study
  • Chthamalus stellatus - acorn barnacle, ranging from subtropical latitudes to northern British isles
  • Semibalanus balanoides - acorn barnacle, ranging from Arctic to southern British isles, overlapping in range with C. stellatus
  • Nucella lapillus - carnivorous gastropod, drills and preys on barnacles
connell field experiment
Connell Field Experiment
  • transplant newly settled Chthamalus to all tidal levels
  • caged some transplants, excluded Nucella
  • allow Semibalanus to settle and cleaned Semibalanus cyprids off some rocks
results of connell experiment
Results of Connell Experiment
  • Chthamalus survival poorer in presence of Semibalanus
  • Chthamalus survival decreased where Semibalanus grew the fastest
  • Chthamalus survival increased in high intertidal due to its resistance to desiccation
conclusions from connell experiments
Conclusions from Connell Experiments
  • Predation important in lower intertidal
  • Biological factors control lower limit of species occurrence
  • Physical factors control upper limit
  • Community structure a function of very local processes (larval recruitment not taken into account as a factor)
slide33

Desiccation

Chthamalus

MHW spring

MHW neap

Mean tide

MLW neap

MLW spring

Competition

Chthamalus

Semibalanus

Semibalanus

Wave Shock

Predation

Physical

factors

Interspecific effects

Adult density

Settlement of cyprids

slide35

Dense population of the barnacle

Semibalanus balanoides

soft sediments
Soft Sediments
  • Zonation not as distinct as on rocky shores
  • Competition - demonstrated by experiments
mud flat field experiments by sarah woodin
Mud Flat Field Experiments by Sarah Woodin
  • burrowing Armandia brevis versus tube builders
  • Cage placed on sediment with top screen: tube builders settled on screen, Armandia burrowed through and reached higher densities than when screen was absent and tube builders settled directly in sediment and established tubes
soft sediments vertical stratification
Soft Sediments - Vertical Stratification
  • Dominant species found at different levels below sediment-water interface
  • Experimentally reduce density of deep-dwelling clams, remaining individuals grow faster - demonstrates effect of density
  • Removal of shallow dwelling species of bivalves has no effect on growth of deeper-dwelling species
slide39

Occurrence of various bivalves at different burrowing

depths in a sand flat in southern California

predation and species interactions
Predation and Species Interactions
  • Predators reduce prey density
  • Prey species compete
  • Conclude: predation may promote coexistence of competing prey species
field experiment of robert paine
Field Experiment of Robert Paine
  • Rocky shores of outer coast of Washington State
  • Principle predator - starfish Pisaster ochraceus
  • Pisaster preys on a wide variety of sessile prey species, including barnacles, mussels, brachiopods, gastropods
slide43

Pacific coast starfish Pisaster ochraceus, flipped over

Left: eating a mussel, Right: eating barnacles

paine experiment and results 1
Paine Experiment and Results 1
  • Removal of Pisaster ochraceus
paine experiment and results 2
Paine Experiment and Results 2
  • Removal of Pisaster ochraceus
  • Successful settlement of recruits of mussel Mytilus californianus
paine experiment and results 3
Paine Experiment and Results 3
  • Removal of Pisaster ochraceus
  • Successful settlement of recruits of mussel Mytilus californianus
  • Other species greatly reduced in abundance, Mytilus californianus became dominant
paine experiment and results 4
Paine Experiment and Results 4
  • Removal of Pisaster ochraceus
  • Successful settlement of recruits of mussel Mytilus californianus
  • Other species greatly reduced in abundance, Mytilus californianus became dominant
  • Conclude: Pisaster ochraceus is a keystone species, a species whose presence has strong effects on community organization mediated by factors such as competition and predation
larval recruitment exerts strong effects 1
Larval Recruitment Exerts Strong Effects1
  • Results from manipulative experiments usually depend upon steady recruitment of larvae of competing species
larval recruitment exerts strong effects 2
Larval Recruitment Exerts Strong Effects 2
  • Results from manipulative experiments usually depend upon steady recruitment of larvae of competing species
  • What if recruitment is variable?
larval recruitment exerts strong effects 3
Larval Recruitment Exerts Strong Effects 3
  • Results from manipulative experiments usually depend upon steady recruitment of larvae of competing species
  • What if recruitment is variable?
  • Competitively superior species might not take over, owing to low rates of recruitment
larval recruitment exerts strong effects 4
Larval Recruitment Exerts Strong Effects 4
  • Results from manipulative experiments usually depend upon steady recruitment of larvae of competing species
  • What if recruitment is variable?
  • Competitively superior species might not take over, owing to low rates of recruitment
  • Recruitment might be reduced if currents are not favorable, high water flow results in flushing of larvae from inshore habitates, poor year for phytoplankton results in poor year for success of plankton-feeding larvae
slide53

Higher phytoplankton

Higher suspension feeder

Growth

Higher recruitment

Lower phytoplankton

Lower suspension feeder

Growth

Lower recruitment

Low freshwater flow,

tidal flushing

High freshwater flow,

tidal flushing

The effects of variation of tidal flushing on larval recruitment in

a semi-enclosed coastal area, such as a bay

disturbance as a factor in intertidal community structure 1
Disturbance as a Factor in Intertidal Community Structure 1
  • Disturbances are physical events that influence the distribution and abundance of organisms
disturbance as a factor in intertidal community structure 2
Disturbance as a Factor in Intertidal Community Structure 2
  • Disturbances are physical events that influence the distribution and abundance of organisms
  • Disturbances may reduce abundance of competing species
disturbance as a factor in intertidal community structure 3
Disturbance as a Factor in Intertidal Community Structure 3
  • Disturbances are physical events that influence the distribution and abundance of organisms
  • Disturbances may reduce abundance of competing species
  • Disturbances may therefore allow coexistence of competitively inferior species, or may allow colonization of species adapted to disturbance
slide57

Postelsia palmaeformis, the palm seaweed, invades

rocks that have been severely disturbed by storms, Spores are

released and travel just a few cm fromthe plant, allowing local

spread of a colonizing individual

spatial scale of disturbance is crucial in subsequent colonization events 1
Spatial Scale of Disturbance is Crucial in Subsequent Colonization events 1
  • A very small scale disturbance in a mussel bed might just result in the mussels moving and sealing off the opened patch
spatial scale of disturbance is crucial in subsequent colonization events 2
Spatial Scale of Disturbance is Crucial in Subsequent Colonization events2
  • A very small scale disturbance in a mussel bed might just result in the mussels moving and sealing off the opened patch
  • Larger patches might be colonized by other species and the patch might last many months or even indefinitely
spatial scale of disturbance is crucial in subsequent colonization events 3
Spatial Scale of Disturbance is Crucial in Subsequent Colonization events3
  • A very small scale disturbance in a mussel bed might just result in the mussels moving and sealing off the opened patch
  • Larger patches might be colonized by other species and the patch might last many months or even indefinitely
  • Therefore, spatial scale of disturbance might affect the spatial pattern of dominance of species, creating a mosaic of long-lived patches
slide61

California mussels

California mussels

California mussels

Small

Newly

Opened

Patch

California mussels

California mussels

California mussels

Bay

Mussels

And

Seaweeds

Large

California mussels

California mussels

California mussels

Disturbance and spatial scale: events following the

opening of a small and large patch in a Pacific coast

mussel bed

estuaries
Estuaries
  • Geologically ephemeral but biologically rich
  • Biodiversity declines with decreasing salinity, especially in so-called critical salnity range of 3-8 o/oo
  • Estuarine flow tends to wash species toward ocean - larval vertical migration can retard loss
estuaries 2
Estuaries 2
  • Species in estuaries often have expanded range of resource exploitation, owing to elimination of species from open coast. Usually estuarine species also occur on open coast, although there are some species found only in low salinity estuarine conditions
estuaries biodiversity
Estuaries - Biodiversity
  • Diversity of marine-related estuarine species declines as you move up the estuary, towards areas of declining salinity
estuaries biodiversity 2
Estuaries - Biodiversity 2
  • There is a critical salinity range, ca. 3-8 o/oo, where diversity is at a minimum
estuaries biodiversity 3
Estuaries - Biodiversity 3
  • At lower salinities, biodiversity increases again, and typical freshwater species are encountered
estuaries biodiversity 4
Estuaries - Biodiversity 4
  • It is believed that the critical salinity range is so species-poor because normal marine species cannot survive there very well, nor can freshwater species, which lack adaptations for dealing with salt, can survive well here either.
  • It has been also suggested that the critical salinity range has very unusual ratios of common inorganic elements (e.g., Cl, Na), which creates further physiological difficulties
salt marshes dominated by spartina spp
Salt Marshes dominated by Spartina spp.
  • Salt marshes are accretionary environments
  • Colonization of sediment by salt marsh plants is followed by trapping of fine particles, accretion of sediments
  • Marsh Spartina spp. plants spread by means of a rhizome system - plants are interconnected and often consist of broad stands of the same genotype
slide71

As initial colonization of Spartina alterniflora results in spread and

trapping of sediment, marsh sediment surface rises, creating a higher

intertidal environment, which favors colonization of a shorter form

Of Spartina alterniflora distant from the water (SAS) and higher marsh

Species, Spartina patens (SP).

spartina sediment and adaptations
Spartina sediment and adaptations
  • Sediment is often anoxic
  • Aerenchymal tissue allows Spartina to exchange gases, even when surrounded by anoxic soil
  • Presence of fiddler crab burrows enhances Spartina growth, perhaps owing to aeration of the soil
slide74

The ribbed marsh mussel, Geukensia demissa,

lives semi-infaunally in marsh sediments. Its

presence also enhances Spartina growth, perhaps

owing to deposition of nutrient rich feces and

pseudofeces.

slide75

Wrack on the surface of a salt marsh. The

role of this material in the nutrient dynamics

of salt marsh ecosystems is controversial.

slide76

Cross-section of Spartina below sediment - note

aerenchymal tissue - allows gas exchange

grazing on spartina spp
Grazing on Spartina spp.
  • Grazing by invertebrates appears to be relatively slight
  • This may be a response to the tough leaves, rich in cellulose, which also has silica
  • Grazing on flowers, however, may be far greater, resulting in frequent failures of seed set
grazing on spartina spp 2
Grazing on Spartina spp. 2
  • Recent research suggests that the presence of the snail Littorina irrorata (found in SE USA) does damage to leaves. This species rises onto the leaves at the time of high tide to avoid predation by crabs
salt marsh creeks
Salt Marsh Creeks
  • Older, mature salt marshes consist of meadows with interspersed creeks
  • The creeks have high nutrient input, support large populations of invertebrates and are often nursery grounds for juvenile fishes and crustaceans
slide80

Short S.

alterniflora

Spartina patens

Tall S. alterniflora

MHW

Eroding

creek

edge

Peat

Geukensia

demissa

Peat

Peat

MLW

Ilyanassa

obsoleta

Creek

Fundulus

heteroclitus

Subhabitats of the Spartina salt marsh environment

vertical zonation
Vertical zonation
  • Salt marshes exhibit the intertidal phenomenon of vertical zonation
  • From low to high intertidal one often finds: S. alterniflora, S. patens, Distichlis spicata, and Juncus gerardi
  • The borders between zones are often quite sharp
vertical zonation 2
Vertical zonation 2
  • Lower intertidal species such as Spartina alterniflora, are more salt tolerant than high intertidal forms, but low intertidal forms are not physiologically limited from growing in high intertidal area
  • High intertidal species are competitively superior to lower intertidal forms, but are not able to survive the longer exposure lower down to salt
slide83

The border between the Spartina alterniflora zone

And the Spartina patens zone, in West Meadow Creek,

Long Island, New York

salt pans
Salt Pans
  • Accumulations of wrack on the upper shore may kill salt marsh grass beneath
salt pans 2
Salt Pans 2
  • If wrack is carried away by currents, evaporation may result in high concentrations of salt, which kills seedlings and prevents recolonization of salt marsh grass species
salt pans 3
Salt Pans 3
  • Recolonization quite difficult unless there are heavy rains, dissolving the salt, or an incursion of grass, which creates shade and traps moisture, thus enhancing dissolution of salt
mangrove forests
Mangrove Forests
  • Dominated by species of mangroves, common in subtropical and tropical protected shores around the world
  • Mangroves broadly rooted but only to shallow depth, in quite anoxic soils
  • Underground roots have projections into air that allow gathering of oxygen
slide89

leaves

fruits

Aerial

roots

Pneumatophores

seedling

Anchoring roots

Roots types, leaves, fruits and seedlings of a mangrove

slide90

Salt gland

Mangroves are very salt-rolerant plants, and leaves have

a salt gland (left), which can excrete salt from cell cytosol to the

leaf surfaces (right)

mangrove forests important features
Mangrove Forests: Important Features
  • High primary productivity
  • High supply of particulate organic matter, especially falling leaves, which subsidize animal growth
  • Zonation of mangrove species
  • Roots support a rich assemblage of sessile marine invertebrates