NR 150 1st Edition Lecture 15 Outline of Last Lecture I Mammals including marine mammals II Marine birds Outline of Current Lecture III Classification of Benthic marine environments by location IV The importance of competition V Benthic organisms live on or in the seafloor Current Lecture I Classification of Benthic marine environments by location a Littoral zone intertidal b Sublittoral zone beyond the littoral zone c Bathyl zone slopes to great depths d Abyssal zone below the bathyl zone e Hadal zone deepest II The importance of competition a Organisms in a community compete with members of the same species and with members of other species for i Food ii Light iii Space iv Other resources III Benthic organisms live on or in the seafloor a Diversity of benthic habitats i Kelp forests These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 1 Seaweeds and marine plants are diverse and effective primary producers 2 2 5 of primary production by multicellular algae seaweeds 3 True marine plants mangroves and sea grasses a Mangroves i Root system traps and holds sediment 1 Subaerial roots of mangrove tree allow it to withstand rise and fall of tides ii Stabilizing effect and expansion of delta and coastal wetlands iii Root system serves as a safe haven for organisms 1 Prop roots serve as sanctuary iv Forests are facing a lot of destruction by humans 4 Seaweeds a Great variety in shape and sizes b More than 7000 species c Nonvascular plants because they don t have to fight gravity i Four requirements of CO2 water nutrients and sunlight to produce carbohydrates are simultaneously present in their bodies d Are held down by a holdfast not a true root e Lightweight structure f Can use nearly all energy for photosynthesis highly efficient g Chlorophytes green dye to the presence of chlorophyll and the lack of accessory pigments i Accessory pigments assist with absorption of light and the transfer of its energy tot chlorophyll aka masking pigments h Phaeophytes brown i Contain chlorophyll and secondary pigment fucoxanthin ii Live in deep depth than chlorophytes iii Include the species of kelps iv Sargassum weeds 1 Spherical air bladders that keep small leaflike blades afloat near the surface 2 Can also grow on rock 3 Can float in hug patches offshore 4 Sargossa sea named after sargassum 5 Provides shelter and food for many organisms v Rockweed 1 Thick and leathery talli 2 Can stand exposure to air 3 Occurs in intertidal zones 4 Provides a Shelter for periwinkle snails and small crustaceans during low tide b Feeding ground for small fish during high tide vi Structure of a kelp 1 Thallus body of a typical multicellular algae 2 Blades leaves used for photosynthesis absorb gases 3 Stipes stem are strong can also be used for photosynthesis shock absorbent 4 Holdfast root anchors but doesn t take up water or nutrients 5 Gas bladder assist seaweed in staying near the surface for sunlight and photosynthesis vii Kelp 1 Largest of brown algae 2 Found below tide level in temperate and sub polar latitudes 3 Provides food and shelter for many organisms 4 Some kelp harvested for food 5 Macrcystis is the largest kelp about 100m330ft 6 Kelp forests are a biodiversity hotspot a Forest structures serve as a source of cover and food b Reduce current velocities which allow for greater nutrient uptake c Primary productivity in healthy forests is high enough to support more than 800 species 7 Giant kelp sea urchins and sea otters are connected together in a food chain a In 18th century trappers began to hunt sea otters b Have very thick fur c By 1911 there were less than 2000 otters left in the world d Sea otters don t have fat layer unlike other marine mammals e No sea otters causes bald patches in the kelp forest i When otter population goes down kelp forest disappears ii Sea urchins eat kelp iii Sea otters live on diet of sea urchin have purple stained teeth and skeletons 8 Protect coastlines by absorbing wave shock a Storms or swells can uproot entire plants and break away fronds b Warm water and storms strong wave energy caused high mortality in the southern California kelp forests 9 Coastal development a Sewage industrial disposal and coastal runoff might contribute to kelp forest degradation b High sedimentation from coastal run off may bury new plant shoots c Reduce growth rates and reproductive success in more toxic water and sediments d Studies on microscopic stages of kelp suggest that kelp is sensitive to sewage industrial waste discharges and other causes of poor water and sediment quality i Rhodophytes i Get their red color from their accessory pigments ii Can live at a depth where human eyes cannot sea light j Economic importance of seaweed i As a food source ii Produce gelatinous chemicals phycocolloids used in food processing 1 Align some uses a Emulsifier in dairy products ice cream cheese b Prevents frosting from drying out c Thickener and emulsifier in tooth paste and shampoos d Used in paper paint and cosmetics e Printing paste in textile industry for sharper prints iii Marine algae s being considered for biofuels 1 Fast growing 2 Renewable 3 Efficient primary producers 4 Doesn t need fresh water to grow ii Rocky intertidal zones 1 Between highest high tide and lowest low tide 2 Sessile and motile organisms 3 Problems a Wave shock b Rapid temperature change c Desiccation 4 Opportunities a Many habitats and niches b Many food sources c Nutrient rich iii Sand beaches 1 Communities exist in one of the Earth s most rigorous habitats a Smaller organisms few have adapted i Problems 1 Sand sharp point abrasive 2 Burrowing is difficult in swirling sand 3 Exposed to predators 4 Tides ii Have adapted 1 Sand crab 2 Fast burrowing clams 3 Sturdy polychete worms 4 Interstitial animals 2 Cobble beaches even more uninviting iv Salt marshes 1 Salt water mixes with freshwater runoff from land a Advantages i Generally no wave shock ii High availability of nutrients b Disadvantages i Varying salinities ii Strong currents associated with tides v Areas around deep vents and seeps vi Coral reefs