Rocky Shore Ecology
[email protected] Upper Shore
Middle Shore
Low Shore Ecosystems on rocky shores have bands of different species across the intertidal zone. The distribution of different species across the rocky shore is influenced by biotic and abiotic factors from above high tide to the sub-tidal zone. Problems of living on a rocky shore
Abiotic Factors Biotic Factors • Wave action • Predation and competition • Water loss and desiccation • Reproduction • Temperature fluctuations • Salinity fluctuations • O2, CO2, pH fluctuations • Range of illumination • Immersion / emersion cycle • Pollution
Wave Action Tidal Cycles Entrance to Baltimore Harbour
January 2014 Near Oregon Institute of Marine Biology,
USA Lewis’ Classic Zonation Description Highly exposed Semi-exposed
Highly sheltered 1) Seaweed Cover 2) Shore aspect
Ballantine Scale
Against desiccation, wave and salinity
• Retreat to sheltered areas • Protective cover • Internal gill • Strong adhesive power (byssus threads, muscular foot) • Flattened body • Red pigment in algae for deep water illumination Some common seaweeds on rocky shores Predation
Primary Producers/Autrophs - algae, phytoplankton and seaweeds
Primary Consumers - grazers and filter-feeders
Secondary Consumers-carnivores e.g. dogwhelks
Tertiary Consumers e.g. birds Food Web Low shore
Fucus serratus
Kelp - Laminaria Mid-shore
Bladder wrack (Fucus vesiculosus) (Sheltered shores only)
Cladophora (Tufted) (usually near /in rockpools) High Shore
Channel wrack - (Pelvetia canaliculata)
Gut weed -Enteromorpha intestinalis Opportunistic – grows near FW runoff Pink Encrusting Seaweeds Lithophyllum spp. &Lithothamnion spp.
Found across the zones Phytoplankton Common animals on rocky shores Periwinkles Littorina spp
•Periwinkles or sea snails – Littorina spp. mainly •Graze on algal biofilms •Different spp. at different shore heights – look at operculum (opening) shape – not colour!! •Can be very small at high shore Common periwinkle Littorina littorina Thick/toothed Topshell Osilinus Purple/flat Topshell lineatus Gibbula umbilicalis • Pronounced tooth or notch • Small topshell 1.6 cm high, on aperture. 2.2 cm across. • Shell has up to 6 whorls. • Large round umbilicus. • Shell dark green, grey or • Dull greenish grey in colour black with brown or red with reddish-purple broad zigzag markings diagonal stripes. • Underside pearly-white Barnacles
•Filter feed using cirri so need water movement •Only sedentary crustacean – not a mollusc!! •Close up operculum when tide is out •Lifespan of 5 to 10 years •Penis size relative to body Barnacles living in gentle waters have long, thin penises best equipped for maximum reach. But those animals living in rough waters have shorter, stouter penises that are better able to withstand strong waves.
Barnacles exhibit phenotypic plasticity, meaning that they can change their penis size depending on competition and environment.
https://www.youtube.com/watch?v=DT fkSr4GAXo Montagu's stellate barnacle Acorn Barnacle (Chthamalus montagui) (Semibalanus balanoides)
Invasive species Austrominius modestus
Limpets
• Limpets (2 species) – Patella species • Graze on biofilms • Look at foot colour (green or orange) • Shell shape and height – look at apex of shell • Make a home scar to maintain position Some species of limpets return to the same spot on the rock known as a "home scar" just before the tide ebbs. All shore heights Low shore & rock pools only
Patella vulgata Patella ulyssiponensis
A keystone species is a plant or animal that plays a unique and crucial role in the way an ecosystem functions.
A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance.
Without keystone species, the ecosystem would be dramatically different or cease to exist altogether. Keystone species •commensalism: occurs when an individual obtains a benefit from a different species without damaging it.
•mutualism: occurs when an individual obtains a benefit from another species and, at the same time, the second species obtains a benefit from the first one. Mutualism is not obligated, which makes it different from symbiosis.
•symbiosis: species benefiting one another but also depending on one another. If one of the symbiotic individuals dies, the other also dies by losing the source from which it was obtaining a benefit. Mussels Mytilus edulis
•Bivalves •Filter feeders – use siphons to suck in water •Close up when tide is out •Form dense beds attached by byssus threads
•Predator on barnacles and mussels •Different shell shapes depending on factors
In evolutionary biology, an evolutionary arms race is a struggle between competing sets of co-evolving genes, traits, or species, that develop adaptations and counter- adaptations against each other, resembling an arms race. These are often described as examples of positive feedback. Guild, in ecology, a group of species that exploits the same kinds of resources in comparable ways. Beadlet Anenome Actinia equina
• They are able to move • 92 tentacles are arranged in six circles • Brood their young (viviparous reproduction) • Very aggressive Bits and Bobs Empty egg cases of the Dog Whelk Mermaid purse
Skate Rabbitfish Sharks Gooseneck Barnacles By the wind sailor - Velella velella Sea Potato Echinocardium cordatum Portuguese man of war
Is a siphonophore, an animal made up of a colony of organisms working together. Whale vomit - Floating Gold
Ambergris
Used in the manufacture of perfume