ch14 - 14-The TidelandsRocky Shores, Soft-Substratum...

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 14-The TidelandsRocky Shores, Soft-Substratum Shores,Marshes, Mangroves, and EstuariesNotes for Marine Biology:Function, Biodiversity, EcologyBy Jeffrey S. LevintonJeffrey S. Levinton 2001ZONATION-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 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)2 SPATIAL GRADIENTS: Vertical Horizontal - changing wave exposureVertical gradient Heat Stress, Desiccation Gas Exchange - dissolved oxygen Reduced feeding time Wave shock Biological interactions - competition,predationHeat Stress/Desiccation Varies on small spatial scales Body size, shape are both important -reduction of surface area/volume reducesheat gain and water loss Evaporative cooling and circulation of bodyfluids aids in reduction of heat loss Well sealed exoskeletons aid in retardingwater loss (acorn barnacles, bivalves)Vertical GradientsHigher intertidal organisms - more resistant toheat and desiccation stress than lowerintertidal organismsHigher intertidal - less time to feed. Sessileforms therefore grow more slowly than lowerintertidal organismsMobile carnivores can feed only at high tide,usually feed more effectively at lower tide levels,which are immersed a greater proportion of thedayOxygen consumptionIntertidal animals usually cannot respire attime of low tideRespiratory organs (gills of polychaetes,bivalves) must be moist to acquire oxygen, andtherefore are usually withdrawn at low tideSome animals - reduce metabolic rate at time oflow tideSome high intertidal animals can respirefrom air (e.g., some mussels) even at lowtide, as long as air is not too dryWave shockAbrasion - particles in suspension scrapedelicate structuresPressure - hydrostatic pressure of breakingwaves can crush compressible structuresDrag - impact of water can exert drag, whichcan pull organisms from their attachments tosurfaces, erode particles from beaches andcarry organisms from their burrows or livingpositionsCauses of Vertical ZonationPhysiological tolerance of different species atdifferent levels of the shoreLarval and adult preference - larvaemay settleat time of high tide at high levels, mobilejuveniles/adultshave a series of behavioralresponses that keep them at certain levels ofshoreCompetition - species may be capable ofexcluding others from certain levels of theshorePredation - mobile predators more effectiveusually on the lower shore: affects distributionsof vulnerable prey speciesInterspecific Interactions andZonationWhy are there vertical zones, withdominance often of single sessile specieswithin a zone?Interspecific Interactions andZonation 2 Why are there vertical zones, withdominance often of single sessile specieswithin a zone?within a zone?...
View Full Document

Page1 / 47

ch14 - 14-The TidelandsRocky Shores, Soft-Substratum...

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online