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Beachcombing. Maia McGuire, PhD Sea Grant Extension Agent. Beach zones. Dune Berm/backshore Wrack line/strand line Foreshore Swash zone Nearshore/breaker zone Offshore. High tide I I Low tide Subtidal. Backshore. Ghost crabs. Wrack line.
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Beachcombing Maia McGuire, PhD Sea Grant Extension Agent
Beach zones • Dune • Berm/backshore • Wrack line/strand line • Foreshore • Swash zone • Nearshore/breaker zone • Offshore High tide I I Low tide Subtidal
Backshore • Ghost crabs
Wrack line • Often created during storm events • Seaweed, debris • Amphipods (beach hoppers) • Sea beans, seashells • Other “treasures”
Sea beans • www.seabean.com • Any of a number of seeds that are adapted to germinate even after spending a period of time floating in water • Mostly from tropical plants, many from vines
Seashells • Phylum Mollusca • Class Gastropoda • Classes Monoplacophora, Polyplacophora (primitive) • Class Bivalvia • Class Scaphopoda (tusk shells) • Class Cephalopoda
Mollusks • Generally have muscular foot, calcareous shell secreted by the mantle, feeding organ called radula • Larvae are often planktonic veligers www.pbs.org www.seaslugforum.net
Gastropods • “Snails” • Head with eyes on tentacles • Usually relatively active/mobile • Usually coiled shell into which animal can retreat • Includes sea slugs • Grazers or predators
Egg collar Moon snail (“shark’s eye”) Operculum (“trap door”)
Bivalves • Shell has 2 (hinged) valves • Adapted to burrow in soft sediments • Most are filter-feeders • May be attached (cement, byssal threads), burrowers/borers or free swimming
Cephalopods • Octopus, Squid, Cuttlefish, Nautilus, Spirula www.manandmollusc.net
Crab shells • Moult or dead? (i.e. will it stink when I get it home?) • Male or female?
Margined Sea Star Astropectenarticulatus Sea Stars Common Sea Star Asterias forbesi?
Jellyfish www.enature.com • Portuguese man-o-war • Don’t touch! • Associated companions—”By-the-wind sailor”, “blue buttons”, purple sea snail, man-o-war slug, man-o-war fish www.amonline.net.au
Cannonball jellyfish www.jaxshells.org
Moon jellyfish www.jaxshells.org
Live critters • Coquinas • Augers • Mole crabs www.jaxshells.com
Marine Debris • PLASTICS!!!
Sand To see a world in a grain of sandand a heaven in a wildflower,hold infinity in the palm of your handand eternity in an hour.William Blake
Where does sand come from? • Erosion of rocks (on land) • NE Florida sand is silica-based; comes mostly from mountains of NC • Formed by marine plants/animals • Shells, sea urchins, etc. • Corals • Calcareous algae (macro- and microscopic)
Sand colors http://www.paccd.cc.ca.us/instadmn/physcidv/geol_dp/dndougla/SAND/SANDHP.htm