The Rocky Intertidal Zone Flashcards
What can rocky shores be?
Either platforms, boulder fields, cliffs or exposed rock formation. Generally steeper approach to the shore. Sediments surrounding the intertidal are coarser
What are the green algae (Chlorophyta)?
Ulva lactuca
What are the red algae (rhodophyta)?
Chondus crispus
What are the brown algae (Phaeophyta)?
Fucus vesiculosus, Laminaria digitata, Fucus serratus
What are algae?
Usually found in refuges - areas hard to graze (but also refuges to desiccation or exposure. Defence - Fucus vesiculosus - galactolipid, Laurencia - phenolic compounds, Corallina - calcification. Most macroalgae are eaten as detritus locally or exported, or eaten as juveniles. Microalgae - highly productive
What are Grazers?
Dominated by gastropods. Limpets: Patella vulgata, P. ulyssiponensis, P. depressa. Protandrous hermaphrodites. Feed using a radula, home scar. Snails - Nucella lapillus, Stermophala umbilicalis, S. cineraria
What are the two types of suspension feeders?
Passive and Active.
What are passive suspension feeders?
Barnacles, Bryozoans, Cnidaria
What are active suspension feeders?
Mussels, clams
What are some predators (UK)?
Lipophrys pholis, Necora puber, Asterias rubens, Pagurus bernhardus, Homarus gammarus, Arenaria interpres, Nucella lapillus, Carcinus maenas, Eulalia clavigera, Octopus vulgaris.
Shore levels and zones - MHWS?
Mean high water spring
Shore levels and zones - MHWN?
Mean High Water Neap
Shore levels and zones - MTL?
Mid tide level
Shore levels and zones - MLWN?
Mean low water neap
Shore levels and zones - MLWS?
Mean low water spring
What are the physical characteristics?
Shore topography, slope, exposure to wave action & ‘fetch’
What do the physical characteristics affect on rocky shore structure?
Cracks & crevices, pools, distribution of microhabitats
What are the physical stress?
Temperature - spawning, photosynthesis, oxygen levels.
Desiccation - fucus
Wave action - Limpets and barnacles
What is zonation & exposure?
Low exposure - shore dominated by brown algae. High exposure - shore dominated by mussels and barnacles. Zones expand on exposed shores.
What are the physical factors in zonation?
Regional scale - sea temperature, air temperature. Local scale - substrate, salinity, wave exposure, topography, water currents (nutrient supply & larval distribution). Upper shore - lichen & littorinid snails, mid shore - barnacles, limpets & fucoids, lower shore - tunicates & kelps. Abiotic factors determine upper limit for many species.
What is macroalgae desiccation tolerance?
Critical desiccation level. Pelvetia canaliculata ~ 95% water loss, Ulva lactuca ~ 97% water loss, Fucus spiralis ~ 80% water loss, Fucus vesiculosus ~ 70% water loss, Fucus serratus ~ 60% water loss, Laminaria digitata ~ 50% water loss.
What are the biological factors of zonation?
Competition - Chtamalus stellatus (higher, more resistant to desiccation) vs Semibalanus balanoides (lower, grows faster). Pelvetia canaliculata outcompeted by faster growing Fucus spiralis. Predation - Mytilus eaten by Nucella lapillus (UK) and Pisaster ochraceus (NE Pacific coasts)
What are the conditions in rock pools?
Fluctuations in temperature, salinity, and pH can be extreme. Especially in high shore rock pool - Photosynthesis, osmoregulation.
