Division Anthophyta

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION CHAPTER OUTLINE 4.1 Division Anthophyta 4.3 Geographic Distribution 4.5 Global Marine Primary Submerged Seagrasses Production © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Mammalian Grazers of Seagrasses Seasonal Patterns of NOT FOR SALE OR DISTRIBUTION4.4 NOT FOR SALE OR DISTRIBUTION Emergent Flowering Plants Marine Primary Production Temperate Seas 4.2 The Seaweeds Warm Seas Structural Features of Seaweeds Coastal Upwelling © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Photosynthetic Pigments Polar Seas NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Reproduction and Growth Kelp Forests

1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Marine Plants © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION enthic marine plants are probably more familiar to even casual seashore observers than are phytoplankton because © Jones &B Bartlettthey are Learning, conspicuous, LLC coastal, macroscopic,© Jones multicellular & Bartlett Learning, LLC NOT FORorganisms SALE OR typically DISTRIBUTION large enough to pick up NOTand examine. FOR SALE They OR DISTRIBUTION all belong to a single kingdom, the Plantae (Fig. 4.1). Like phytoplankton, these plants need sunlight for photosynthesis and are confined to the© Jones photic & zone, Bartlett but Learning, the additional LLC need for a © Jones & Bartlett Learning, LLC hard substrate onNOT which FOR to SALE attach OR limits DISTRIBUTION the distribution of NOT FOR SALE OR DISTRIBUTION benthic plants to that narrow fringe around the periphery of the oceans where the sea bottom is within the photic zone (the inner© shelfJones of & Fig. Bartlett 1.45). Learning, Some benthic LLC plants inhabit intertidal© Jones & Bartlett Learning, LLC areasNOT and FOR must SALE confront OR DISTRIBUTION the many tide-induced stressesNOT that FOR SALE OR DISTRIBUTION affect their animal neighbors (discussed in Chapter 9). Their restricted near-shore distribution limits the global importance of benthic plants as primary producers in the marine environ- © Jones &ment. Bartlett Yet Learning,within the LLC near-shore communities© Jones in which & Bartlett they Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION live, they play major roles as first-trophic-level organisms. The abundant plant groups so familiar on land—ferns, mosses, and seed plants—are poorly represented or totally absent from the sea.© Instead,Jones & most Bartlett marine Learning, plants LLC belong to two © Jones & Bartlett Learning, LLC divisions, PhaeophytaNOT FOR and Rhodophyta,SALE OR DISTRIBUTION that are almost com- NOT FOR SALE OR DISTRIBUTION pletely limited to the sea. Two other divisions, Chlorophyta and Anthophyta, are found most commonly in fresh water and on land,© Jones yet & they Bartlett are importantLearning, LLCmembers of some shallow© Jones & Bartlett Learning, LLC coastalNOT marine FOR SALE communities. OR DISTRIBUTION The characteristics of theseNOT di- FOR SALE OR DISTRIBUTION visions are summarized in Table 4.1. We begin our examination of marine plants with a familiar group, the Anthrophyta or © Jones &flowering Bartlett Learning,plants, and LLC then proceed to the seaweeds.© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 97 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC MONERA © JonesPROTISTA & Bartlett Learning,PLANTAE LLC Rhodophyta NOT FOR SALE OR DISTRIBUTION “Bacteria” NOT FOR SALE OR DISTRIBUTION 3 Divisions “Phytoplankton” Phaeophyta introduced 2 Divisions Chlorophyta in Chapter 2 introduced Anthophyta in Chapter 3 Earliest FUNGI © JonesLife & Bartlett Learning, LLC 1 Kingdom© Jones & Bartlett Learning, LLC Forms introduced in NOT FOR SALE OR DISTRIBUTION“Protozoa” ChapterNOT 5 FOR SALE OR DISTRIBUTION 3 Phyla introduced ANIMALIA in Chapter 5 25 Phyla introduced in © Jones & Bartlett Learning, LLC © JonesChapters & Bartlett 5–7 Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Figure 4.1

The phylogenetic tree introduced in Figure 2.7,emphasizing the four divisions of kingdom Plantae described in this chapter.

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Major Divisions of Marine Plants and Their General Characteristics NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Approximate Percentage Division number of of species General size Photosynthetic Storage (common name) living species marine and structure pigments products Habitat Phaeophyta 1500 99.7 Multicellular, Chlorophyll a,c Laminarin Mostly benthic

Table 4.1 Table © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC (brown algae) macroscopic Xanthophylls and others NOT FOR SALE OR DISTRIBUTION Carotenes NOT FOR SALE OR DISTRIBUTION Rhodophyta 4000 98 Unicellular and Chlorophyll a Starch and Benthic (red algae) multicellular, Carotenes others mostly macroscopic Phycobilins © JonesChlorophyta & Bartlett Learning,7000 13LLC Unicellular and © JonesChlorophyll & a,b BartlettStarch Learning, Mostly LLCbenthic (green algae) multicellular, Carotenes NOT FOR SALE OR DISTRIBUTION microscopic to NOT FOR SALE OR DISTRIBUTION macroscopic Anthophyta 250,000 0.018 Multicellular, Chlorophyll a,b Starch Benthic (flowering plants) macroscopic Carotenes

© Jones & BartlettAdapted Learning, from Segal et al.,1980;Dawson,1981;and LLC Kaufman et al.,1989. © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Submerged Seagrasses Twelve genera of seagrasses (classified in four families), Division Anthophyta © Jones & Bartlett Learning, LLCincluding about 60 species,© are Jones dispersed & aroundBartlett coastal Learning, LLC 4.1 Marine flowering plants are abundant in lo- waters of the world. Half of these species are restricted NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION calized areas along some seashores and in backwater to the tropics and subtropics and are seldom found bays and sloughs. Seagrasses are exposed to air only deeper than 10 m. The four common genera found in during very low tides, whereas salt marsh plants and the United States are Thalassia, Zostera, Phyllospadix, mangroves are emergent and are seldom completely and Halodule. Thalassia, or turtle grass (Fig. 4.2a), is inundated© Jones by & seawater.Bartlett These Learning, plants representLLC a sec- common© in Jones quiet waters & Bartlett along most Learning, of the Gulf LLC Coast ondaryNOT FOR adaptation SALE to OR the DISTRIBUTIONmarine environment by a from FloridaNOT to FOR Texas. SALE Zostera, ORor eelgrass DISTRIBUTION (Fig. 4.2b), few species of a predominantly terrestrial plant group, is widely distributed along both the Atlantic and Pa- the flowering plants (division Anthophyta). Flower- cific coasts of North America. Zostera normally inhab- ing plants are characterized by leaves, stems, and roots, its relatively quiet shallow waters but occasionally is © Jones & Bartlettwith water- Learning, and nutrient-conducting LLC structures run-© Jonesfound & Bartlettas deep as 50Learning, m in clear water.LLC Surf grass, Phyllo- NOT FOR SALEning throughOR DISTRIBUTION all three of these basic structures. NOT FORspadix SALE(Fig. 4.2c), OR DISTRIBUTIONis found on both sides of the North 98 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. another plant (also covered with a surface film of slime), © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC the two slime layers combine to produce a firm bond NOT FOR SALE OR DISTRIBUTION NOTbetween FOR theSALE pollen OR grain DISTRIBUTION and the stigma, and fertilization follows. This two-component adhesive acts like epoxy glue to produce a strong bond after the separate components are mixed. It also provides a mech- © Jones & Bartlett Learning,anism LLC for selecting between ©compatible Jones & and Bartlett foreign Learning, LLC NOT FOR SALE OR DISTRIBUTIONtypes of pollen grains. Only onNOT contact FOR with SALE pollen OR of DISTRIBUTION the same species will the stigma–pollen bond be formed. Foreign pollen grains do not adhere and are washed away, possibly to try again on another plant. Mature seeds of each type of seagrass are adapted © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC to their preferred habitat. Eelgrass seeds drop into NOT FOR SALE OR DISTRIBUTION the mud andNOT take root FOR near SALE the parent OR plant,DISTRIBUTION whereas (a) (b) (c) the fruits of Thalassia may float for long distances Figure 4.2 before releasing their seeds in the surf. The fruits Three common seagrasses from different marine climatic regions:(a) turtle surrounding individual seeds of Phyllospadix are © Jones &grass, BartlettThalassia; (b) Learning, eelgrass,Zostera; andLLC (c) surf grass,Phyllospadix. © Jonesequipped & Bartlettwith bristly Learning, projections. LLC When shed into NOT FOR SALE OR DISTRIBUTION NOTthe FOR surf, SALEthese bristles OR DISTRIBUTION snag branches of small seaweeds, and the seeds germinate in place. Pacific and inhabits lower intertidal and shallow sub- Like reef-forming corals and tropical mangroves, tidal rocks that are subjected to considerable wave and countless seagrass blades growing in all tropical la- surge action. Halodule prefers sandy areas with lower goons provide a prodigious surface area on which other © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC salinity. organisms (epibionts) can attach and grow. In St. Ann’s Most seagrasses NOTproduce FOR horizontal SALE OR stems, DISTRIBUTION or Bay, Jamaica, Silvia Maciá determinedNOT FOR that, SALE on each OR DISTRIBUTION rhizomes, that anchor the plants in soft sediments square meter of seafloor, seagrass blades provide an or attach them to rocks (Fig. 4.2). From the buried average of nearly 300 m2 of surface on which epibionts rhizomes, many erect leaves develop to form thick can attach. This vast expanse of surface area does not green© lawns Jones of vegetation.& Bartlett These Learning, plants are LLC a staple go unnoticed© by Jones local organisms. & Bartlett About Learning, 175 species LLC of foodNOT for near-shore FOR SALE marine OR animals DISTRIBUTION and migratory plants and animalsNOT haveFOR been SALE observed OR livingDISTRIBUTION attached birds. Densely matted rhizomes and roots also accu- to blades of turtle grass in the Caribbean region, in- mulate sediments and organic debris to alter further cluding various algae, sponges, hydroids, sea anemones, the living conditions of the area. amphipods, ectoprocts, tunicates, annelids, and snails. Seagrasses reproduce either vegetatively by These same seagrass beds support the foraging activ- © Jones &sprouting Bartlett additional Learning, vertical LLC leaves from the length- © Jonesities of a& few Bartlett species ofLearning, unusual marine LLC tetrapods that NOT FORening SALE horizontal OR DISTRIBUTION rhizomes or from seeds produced NOTare FOR unusual SALE simply OR because DISTRIBUTION they are herbivores (see in simple flowers. The purpose of most showy flow- later here). ers on land plants is to attract insects or birds so that If you were to visit a tropical seagrass meadow pollen grains are transferred from one flower to an- with a mask and snorkel, your first impression would other and cross-fertilization© Jones occurs. & Bartlett Pollen Learning,grains likely LLC be that there is very little© Jones life in seagrass & Bartlett beds Learning, LLC contain the plant’s spermNOT cells, FOR but SALE submerged OR DISTRIBUTION sea- (Fig. 4.3). This is because, otherNOT than FOR the SALEepibionts, OR DISTRIBUTION grasses use water currents for pollen transport. In all which simply appear as a whitish fuzz on older blades, seagrasses, pollination occurs underwater. you would encounter very few animals. The primary Some seagrasses, including Zostera, produce reason for the paucity of animals among seagrass is threadlike pollen grains about 3 mm long (about 500 that this habitat experiences a great deal of sedimen- times© longer Jones than & theirBartlett cargo, Learning, the microscopic LLC chro- tation. Waves© arriveJones from & theBartlett open sea Learning, and break LLCon mosome-carryingNOT FOR SALEsperm cells). OR AfterDISTRIBUTION release, the pollen the reef flat,NOT creating FOR sediment-laden SALE OR DISTRIBUTION currents that grains of Zostera become ensnared on the stigma, the stream into the lagoon. In the lagoon, the currents pollen-receptive structure of the female flower, and slow as they are forced to meander through millions fertilization occurs. Thalassia produces small round of seagrass blades. This decreased current velocity is © Jones &pollen Bartlett grains Learning,released in a thread LLC of sticky slime. When © Jonesinsufficient & Bartlett to transport Learning, larger sediment LLC particles, NOT FORthe SALE slime ORthread DISTRIBUTION lands on the appropriate stigma of NOTand FOR they SALEbegin to OR settle DISTRIBUTION onto the sea floor among the Division Anthophyta 99 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. dendron, Syringodium, and Zostera. Algae also are eaten © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC but only in limited amounts if seagrasses are abun- NOT FOR SALE OR DISTRIBUTION NOT FORdant. SALE At the ORvery DISTRIBUTION southern extent of their range, dugongs in subtropical Moreton Bay, Australia also consume sessile benthic invertebrates including sea squirts and polychaete worms, presumably to augment © Jones & Bartlett Learning, LLCthe protein content of their© otherwiseJones & low-protein Bartlett dietLearning, LLC NOT FOR SALE OR DISTRIBUTIONof seagrasses. NOT FOR SALE OR DISTRIBUTION The strongly down-turned snout of the dugong causes its mouth to open almost straight downward, and it is virtually an obligate bottom feeder subsist- ing on seagrasses less than 20 cm high. Manatees, in © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Figure 4.3 contrast, have only a relatively slight deflection and NOT FOR SALE OR DISTRIBUTION are generalists,NOT FOR feeding SALE at any OR level DISTRIBUTION in the water col- A typical view of a seagrass-covered lagoon floor. umn from bottom to surface, and are able to take floating vegetation easily. Manatees graze on a large seagrass. Many organisms cannot endure this high rate variety of coastal and freshwater vegetation, includ- © Jones & Bartlettof sedimentation Learning, because LLC it interferes with feeding,© it Jonesing &several Bartlett species Learning, of submerged LLC seagrasses, floating NOT FOR SALEhinders OR respiration DISTRIBUTION by clogging gills, it easily abradesNOT FORfreshwater SALE plants OR (DISTRIBUTIONHydrilla and water hyacinths), and soft tissues, and it buries smaller organisms in an even the leaves and shoots of emergent mangroves. avalanche of particles; however, the high sedimenta- Sirenians are the only marine mammals that have tion rates that repel many potential seagrass residents a prehensile snout. The short muscular snout of man- is actually attractive to deposit-feeding sea cucumbers atees is covered with modified vibrissae that have a © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC and mojarras, silvery fishes that make a living by strain- prehensile function to bring vegetation to the mouth ing mouthfuls of sedimentNOT FOR through SALE their OR gill DISTRIBUTION rakers in (Fig. 4.4). During feeding, NOTdugongs FOR gouge SALE visible OR tracks DISTRIBUTION search of organic morsels. into seagrass stands and bottom sediments while Macroalgae such as Halimeda, Penicillus, Acetab- grubbing seagrasses from the bottom. Each track fol- ularia, and Caulerpa are often very common in trop- lows a serpentine course and appears to represent the ical© Joneslagoons, &and Bartlett because someLearning, of these LLCalso precipitate continuous© Jones feeding & effort Bartlett of a single Learning, dive. Like LLC ter- CaCONOT3 FORthat they SALE have OR extracted DISTRIBUTION from seawater (like restrial mammalianNOT FOR herbivores,SALE OR theDISTRIBUTION cheek teeth of corals), they contribute additional carbonate sedi- both manatees and dugongs are adapted for grind- ment to the sea floor after they die. About 85% of the ing cellulose-rich vegetation.

biomass of the Caribbean’s Halimeda is CaCO3, and Even though seagrass meadows are very produc- this genus alone can contribute three kilograms of tive, green sea turtles, manatees, and dugongs are the © Jones & Bartlettcarbonate Learning, sand per square LLC meter in just 1 year. © Jonesonly & large Bartlett herbivores Learning, to graze onLLC them commonly. The NOT FOR SALEThe OR expansive DISTRIBUTION meadow of seagrass and macroal-NOT FOR SALE OR DISTRIBUTION gae that grows in most tropical lagoons is an irre- sistible source of food to several common herbivores. In addition to high concentrations of herbivorous parrotfishes and ©surgeonfishes Jones & Bartlett that leave Learning, the safety LLC © Jones & Bartlett Learning, LLC of the adjacent reefNOT at FORnight SALEto forage OR in DISTRIBUTIONseagrass, NOT FOR SALE OR DISTRIBUTION green sea turtles and a few species of large marine mammals rely extensively on tropical seagrass beds and are important components of seagrass communities. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC MammalianNOT FOR Grazers SALE of OR Seagrasses DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Manatees and dugongs (order Sirenia) are the only marine mammals that are herbivores (see Chapter 7). Manatees and dugongs consume a wide variety of trop- Figure 4.4 © Jones & Bartlettical and Learning,subtropical seagrasses,LLC including Enhalus,© JonesA Caribbean & Bartlett manatee manipulatingLearning, plant foodLLC with its vibrassae snout NOT FOR SALEHalophila, OR DISTRIBUTIONHalodule, Cymodocea, Thalassia, Thalasso-NOT FORand flippers. SALE OR DISTRIBUTION 100 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. low energy value and protein content of a seagrass diet not provide optimal growth conditions for Spartina, © Jones & Bartlett Learning, LLC © Jones for& Bartlett manatees andLearning, dugongs LLChas been suggested as con- even though the salt marsh is its natural habitat. Com- NOT FORtributing SALE factorsOR DISTRIBUTION to their slow and sluggish behavior, NOTpetition FOR withSALE other OR land DISTRIBUTION and freshwater plants may low metabolic rates relative to other marine mammals, have forced Spartina and other salt-tolerant species and the consequent need for these endotherms to re- into the more restricted areas of the salt marshes. main in tropical and warm subtropical waters. Several Salt marsh plants contribute heavily to detritus other species of marine© mammals Jones & (described Bartlett in Learning, Chap- production LLC in their protected© environmentsJones & Bartlett as well Learning, LLC ter 7) also occupy tropicalNOT waters, FOR butSALE none OR is as DISTRIBUTION com- as in nearby bays and estuaries.NOT Some FOR feature SALE exten- OR DISTRIBUTION pletely restricted to warm and shallow waters as these sive stands containing several species of emergent large, slow, herbivorous sirenians. grasses, especially various species of Spartina. At slightly higher elevations, these grasses give way to succulents (Salicornia and Suaeda), a variety of reeds Emergent© Jones Flowering & Bartlett Plants Learning, LLC © Jones & Bartlett Learning, LLC and rushes, and the brush and smaller trees of the lo- SeveralNOT other FOR species SALE of flowering OR DISTRIBUTION plants often exist cal woodland.NOT These FOR lush SALEpastures OR are extremelyDISTRIBUTION pro- partially submerged on bottom muds of coastal salt ductive and harbor a unique assemblage of organisms, marshes protected from strong ocean wave action. including commercially important shellfish and fin- These plants are usually situated so that their roots fishes. Yet as large urban centers develop near them, © Jones &are Bartlett periodically, Learning, but not constantly, LLC exposed to tidal © Jonesthey have & Bartlettbecome popular Learning, sites for LLC waste dumping, NOT FORflooding. SALE TheyOR DISTRIBUTION are terrestrial plants that have evolved NOTrecreation, FOR SALE dredging OR and DISTRIBUTION filling, and other detrimen- various degrees of tolerance to excess salts from sea tal uses. The degradation of salt marshes is a serious spray and seawater. Some even have special struc- and worldwide problem that becomes more severe tural adaptations for their semi-marine existence. as human populations expand and place more pres- The cordgrass, Spartina (see Fig. 8.9a), for example, sure on these fragile habitats. The issues surround- © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC actively excretes excess salt through special two- ing modification and degradation of salt marshes are celled salt glands on itsNOT leaves. FOR Even SALE so, several OR species DISTRIBUTIONdiscussed further in ChapterNOT 8. FOR SALE OR DISTRIBUTION of Spartina have higher experimental growth and sur- Several species of shrubby to treelike plants, the vival rates in freshwater than in seawater. This mangroves, create dense thickets of tidal woodlands difference strongly suggests that the salt marsh does known as mangals (Fig. 4.5). Mangals dominate large © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Figure 4.5 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR DenseSALE mangal OR thicket DISTRIBUTION lining a tidal channel. NOT FOR SALE OR DISTRIBUTION Division Anthophyta 101 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONin progress NOT FOR SALE OR DISTRIBUTION marshes are the most important communities, eco- © Jones & Bartlettnomically Learning, and eco- LLC © Jones & Bartlett Learning, LLC Can an ArmyNOT of FOR SALE logically,OR DISTRIBUTION along the NOT FOR SALE OR DISTRIBUTION eastern seaboard Snails Destroy a and Gulf of Mexico Salt Marsh? because they serve as shoreline © Jones & Bartlett Learning, buffers,LLC sediment © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONstabilizers, nutrient NOT FOR SALE OR DISTRIBUTION and sediment fil- Shoreline communities are the most ters, and essential popular communities in America. The habitat for juvenile Figure B4.1 Marsh periwinkles in unusually high densities on cordgrass U.S. Census Bureau estimates that 53% and adult fishes in Louisiana. © Jones & Bartlettof Americans Learning, reside within LLC our 673 and seabirds;© thus, Jones & Bartlett Learning, LLC NOT FOR SALEcoastal OR counties, DISTRIBUTION even though they determining theNOT FOR SALE OR DISTRIBUTION constitute just 17% of the total land cause of this cordgrass Enter Dr. Brian Silliman, an ecolo- area in America (excluding Alaska). die-off is crucial. gist in the Department of Zoology at the This high density of shoreline-dwelling Much like subtidal eel grass in New University of Florida in Gainesville. Dr. humans (300 people per square mile in England, red mangroves along the Silliman knew that the most abundant U.S. coastal counties© vs.Jones a national & Bartlett av- world’s Learning, tropical coasts, LLC and giant kelp herbivore© inJones coastal &communities Bartlett of Learning, LLC erage of less than 100NOT persons FOR per SALE offOR America’s DISTRIBUTION west coast, cordgrass the easternNOT United FOR States SALE was theOR DISTRIBUTION square mile) has transformed coastal (Spartina alterniflora) is the dominant, marsh periwinkle, Littoraria irrorata, a areas into extremely valuable real es- habitat-forming, soft-shoreline plant gastropod grazer (Fig. B4.1) that dam- tate, with $150 billion per year being from Newfoundland to Florida and aged healthy cordgrass while grazing generated by near-shore communities throughout the Gulf of Mexico. For on their fungal food (pathogenic fungi via© tourism,Jones aquaculture, & Bartlett and Learning, fisheries. moreLLC than half a century, salt marsh© Jonesexhibit & Bartlett enhanced Learning, growth when LLC grow- NOTSuch FOR fondness SALE for the OR coast DISTRIBUTION is not ecologists have been dogmaticallyNOT FORing inSALE periwinkle-created OR DISTRIBUTION grazer unique to Americans, and coastal pop- constrained by the paradigm that cord- wounds on cordgrass). Thus, these ulation explosions worldwide are of- grass health was primarily under the snails kill cordgrass not through direct ten blamed for global degradation of control of soil-related stresses (such as consumption of the plant, but indi- seagrass beds, mangrove swamps, salinity or pH) or nutrient availability, rectly via facilitating the growth of © Jones & Bartlettcoral reefs, Learning, salt marshes, LLC oyster reefs, so-called bottom-up© Jones factors. & Thus,Bartlett Learning,pathogenic fungi LLC during their fungal- NOT FOR SALEand kelp OR forests DISTRIBUTION via anthropogenic much of the investigationNOT FOR into SALE the re- OR farmingDISTRIBUTION activities. He also knew that habitat destruction, eutrophification, cent cordgrass die-off in the south- southeastern populations of blue or alteration of food webs. One such eastern United States has centered crabs, Callinectes sapidus, a major die-off has occurred in recent years around edaphic, or soil-related, stress- predator of periwinkles, had declined along the southeastern and gulf ors, especially because a severe 40% to 85% in recent years because of coasts of America, ©where Jones greater & thanBartlettdrought Learning, in the southern LLC United States overfishing.© Jones Moreover, & heBartlett had ob- Learning, LLC 100,000 hectares (250,000NOT acres)FOR of SALE salt fromOR 1999 DISTRIBUTION to 2001 resulted in increases served thatNOT snail FOR densities SALE in die-off OR DISTRIBUTION marsh have been lost along more than in salinity and decreased moisture and sites reached 2000 individuals per m2, 1500 km of coastline. These salt pH of marsh soils. that snails were essentially absent on

© Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTIONin progress exposed mudflats, that snail density fronts and that the presence of snail peaked in “snail fronts” along the die- fronts results in an increase in the die- off/healthy border, and that snail den- off area of 15% to 185%. Second, to test sity decreased markedly© within Jones stands & Bartlettwhether theLearning, drought and LLC the snails © Jones & Bartlett Learning, LLC of healthy cordgrass. Thus,NOT he hypoth-FOR SALEcould OR have DISTRIBUTION interacted together to Can anNOT Army FOR of SALE OR DISTRIBUTION esized that fungal-farming snails at cause the initial marsh die-off and lo- Snails Destroy a high density could destroy the marsh calized disturbances, he manipulated canopy in a “top-down” manner and snail densities and soil salinities at 12 Salt Marsh? wondered whether drought-related field sites in Georgia and Louisiana. stress© could Jones act synergistically & Bartlett with Learning,When LLC grazing snails were removed, © Jones & Bartlett Learning, LLC the periwinklesNOT FOR to worsen SALE the OR die-off. DISTRIBUTIONcordgrass biomass increased by moreNOT FOR SALE OR DISTRIBUTION In short, he sought to determine than three orders of magnitude, a whether drought-induced elevations strong indication that top-down control in soil salinity, recent increases in of growth by snails is significant. When abled snail populations to increase snail abundance because of crab de- Dr. Silliman increased soil salinity to dramatically. Next, snail density was © Jones &creases, Bartlett or a synergisticLearning, interaction LLC 56‰ (to simulate drought© Jones conditions), & Bartlettfurther Learning, increased LLCby the loss of cord- NOT FORbetween SALE both OR factors DISTRIBUTION was responsible Spartina growth wasNOT reduced FOR by SALE45%, ORgrass DISTRIBUTION because the snails were forced for the loss of cordgrass. demonstrating that bottom-up factors to clump on whatever vegetation To test his hypothesis, Dr. Silliman also could contribute to a cordgrass remained. Finally, runaway grazing by conducted two experiments, and his die-off. Finally, when Spartina was snails in density-dependent, marching results were quite unexpected. First, to exposed to both increased soil salinity fronts persisted for more than 1 year af- determine whether snail© fronts Jones alone & Bartlettand dense Learning, populations ofLLC grazing peri- ter the drought© ended,Jones resulting & Bartlett in even Learning, LLC contribute to marsh die back,NOT he FOR ex- SALEwinkles, OR the DISTRIBUTION biomass of cordgrass de- greater loss ofNOT wetland FOR vegetation. SALE OR DISTRIBUTION cluded snails from the marsh borders creased by 84%. Hence, Dr. Silliman These exciting results challenge and watched the cordgrass grow was able to conclude that environmen- traditional views of salt marsh ecol- (Fig. B4.2). This experiment showed that tal stress (a drought) had a significantly ogy and the relative importance of marsh periwinkles leave exposed mud- greater negative effect on cordgrass top-down versus bottom-up causal flats in© their Jones wakes & as Bartlett they pass in Learning,growth LLC and survival when coupled with© Jonesfactors. & When Bartlett coupled Learning, with similar LLC NOT FOR SALE OR DISTRIBUTION unusually high den-NOTobservations FOR SALE of grazingOR DISTRIBUTION fronts mow- sities of grazing ing their way through other marine snails. A likely sce- habitats (e.g., sea urchins in kelp nario that Dr. Silli- forests, crown-of-thorns sea stars man has proposed on coral reefs, and snow geese in © Jones & Bartlett Learning, LLC ©to Jonesexplain this & ex-Bartlettarctic Learning, salt marshes), LLC Dr. Silliman NOT FOR SALE OR DISTRIBUTION NOTtreme FORdie-off in-SALE ORwas DISTRIBUTIONled to the sobering conclusion cludes several that rapid and extensive marine habi- stages. First, an in- tat loss is usually coupled with an- tense multiyear thropogenic alterations of food webs drought initiated the or nutrient cycling. Could such large- © Jones & Bartlett Learning,Spartina LLCdie-off scale die-offs© ofJones marine communities& Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONwhile a concomitant become moreNOT common FOR if globalSALE OR DISTRIBUTION Figure B4.2 Snail-exclusion cages permit exuberant cordgrass growth in the reduction in blue warming continues at predicted center of a snail-ravaged mudflat. crab predators en- rates?

© Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. expanses of muddy shores in warmer climates and Members of these mangal communities are sup- © Jones & Bartlett Learning, LLC © Jones & Bartlettare excellent Learning, examples LLC of emergent plant-based com- ported on their muddy substrate by numerous prop NOT FOR SALEmunities. OR MangrovesDISTRIBUTION range in size from small shrubsNOT FORroots SALE that grow OR down DISTRIBUTION from branches above the wa- to 10-m-tall trees whose roots are tolerant to sea- ter. The pattern of mangrove development illustrates water submergence and are capable of anchoring in well a series of adaptations needed to exist on muddy soft muds. Collectively, mangrove plants, the major tropical shores (Fig. 4.7). Red mangroves (Rhizophora) component of mangal© Jones communities, & Bartlett line Learning, about two LLCproduce seeds that germinate© Jones while still & Bartlett hanging from Learning, LLC thirds of the tropicalNOT coastlines FOR SALE of the world OR DISTRIBUTION (Fig. 4.6). the branches of the parentNOT tree. FOR As SALE the seedlings OR DISTRIBUTION

Distribution of salt marshes (orange) and mangals (maroon).

Figure 4.7 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALEGermination OR cycleDISTRIBUTION of a mangrove seedling. NOT FOR SALE OR DISTRIBUTION 104 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. develop and grow longer, their bottom ends become losses to seafood production for Louisiana and about © Jones & Bartlett Learning, LLC © Jones heavier.& Bartlett When Learning, the seedlings LLC eventually drop from $200 million in losses to Alabama and Mississippi, NOT FORthe SALE parent OR plant DISTRIBUTION into the surrounding water, they float NOTrespectively. FOR SALE Moreover, OR DISTRIBUTION these initial losses to seafood upright, bobbing at the water’s surface, are dispersed production may persist because benthic communities by winds or tides, and finally implant in muddy sed- along this coastline experienced significant reductions iments along shallow shorelines. There, the seedlings in biodiversity as well as shifts in the composition and promptly develop small© Jones roots to & anchor Bartlett themselves Learning,ranking LLC of dominant taxa. © Jones & Bartlett Learning, LLC and continue to mature.NOT The FOR resulting SALE tangle OR of grow-DISTRIBUTION NOT FOR SALE OR DISTRIBUTION ing roots traps additional sediments and increases SUMMARY POINTS the structural complexity of mangal communities. Birds, insects, snails, and other terrestrial animals oc- Division Anthophyta cupy the upper leafy canopy of the mangroves, and • Multicellular plants in the sea are dominated © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC a variety of fishes, crustaceans, and mollusks live on by brown and red algae, with green algae and or amongNOT the FOR root SALE complex OR growing DISTRIBUTION down into the some floweringNOT FOR plants SALE also playingOR DISTRIBUTION important mud. Because the leafy portions of these plants are roles. above the water level, few marine animals graze di- • About 60 species of seagrasses thrive through- rectly on mangrove plants. Instead, leaves falling from out the world along subtidal soft-bottom shore- © Jones &these Bartlett plants intoLearning, the quiet LLC waters surrounding their © Joneslines. & Bartlett Most seagrasses Learning, reproduce LLC vegetatively NOT FORroots SALE provide OR DISTRIBUTION an important energy source for the NOT FORvia horizontalSALE OR rhizomes DISTRIBUTION or sexually via under- detritus-based food webs of these communities. water pollination of tiny flowers followed by In the United States, the distribution of mangals fruit production. reflects their need for warm waters protected from • Additional flowering plants, such as marsh wave action; they are found only along portions of grasses and mangals, grow on soft bottoms in © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC the Gulf of Mexico and the Atlantic coast of Florida. the intertidal zone. All types of marine flower- The south coast of FloridaNOT is FOR dominated SALE by OR extensive DISTRIBUTIONing plants host a unique communityNOT FOR of organisms SALE OR DISTRIBUTION interconnected shallow bays, waterways, and man- within the habitat that they create. gals. These mangals form a nearly continuous narrow • Manatees and dugongs are the only herbivo- band along the coast, with smaller fingers extending rous marine mammals. They use their prehensile inland© alongJones creeks. & Bartlett Inland, Learning, toward the freshwaterLLC snouts ©to grazeJones on a& variety Bartlett of sea Learning, grasses and LLC Everglades,NOT FORthe mangroves SALE ORare not DISTRIBUTION high, but tree height the occasionalNOT FOR macroalga. SALE OR DISTRIBUTION of red, black, and white mangroves (the three most common species in the southeast United States) increases to as much as 10 m at the coast. It is these taller coastal members of mangal communities that © Jones &are Bartlett especially Learning, prone to hurricane LLC damage. In 1992, © Jones &The Bartlett Seaweeds Learning, LLC NOT FORHurricane SALE OR Andrew DISTRIBUTION cut a swath of destruction across NOT4.2 FOR SALEBy far, most OR largeDISTRIBUTION conspicuous forms of at- south Florida with sustained winds up to 242 km/hr. tached marine plants are seaweeds. The term seaweed The accompanying storm surge lifted the sea surface is used here in a restricted sense, referring only to more than 5 m above normal levels. Some of the more macroscopic members of the plant divisions Chloro- exposed coastal mangal© Jones communities & Bartlett experienced Learning,phyta LLC (green algae), Phaeophyta© Jones (brown & algae), Bartlett and Learning, LLC greater than 80% mortality,NOT dueFOR mostly SALE to wind OR effectsDISTRIBUTIONRhodophyta (red algae) (TableNOT 4.1). FOR These SALE are mul- OR DISTRIBUTION and lingering problems of coastal erosion. ticellular plants that do not produce seeds or flow- On August 29, 2005, Hurricane Katrina struck the ers, yet meet all the criteria for kingdom Plantae as coasts of Louisiana, Mississippi, and Alabama. This summarized in section 2.2. important coastline houses 15 major fishing ports, Seaweeds are abundant on hard substrates in in- nearly© 200 Jones seafood & processingBartlett plants,Learning, and nearly LLC 15,000 tertidal zones© Jonesand commonly & Bartlett extend Learning, to depths LLC of state-NOT and federallyFOR SALE permitted OR DISTRIBUTIONfishing vessels, which 30 to 40 m.NOT In clear FOR tropical SALE seas, OR some DISTRIBUTION species of together produce 10% of the shrimp and 40% of the red algae thrive at depths as great as 200 m, and one oysters consumed in the United States. Two months species has been reported as deep as 268 m in the after Katrina made landfall, her effects on seafood pro- Bahamas. Many seaweeds tolerate or even require © Jones &duction, Bartlett and Learning,coastal fauna LLCand habitats were assessed. © Jonesextreme & surf Bartlett action onLearning, exposed rocky LLC intertidal out- NOT FORIt SALE is estimated OR DISTRIBUTION that Katrina caused $1.1 billion in NOTcrops, FOR where SALE they OR are DISTRIBUTION securely fixed to the solid The Seaweeds 105 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. substrate. Where they are abundant, seaweeds can arrangement. Several larger species of brown algae © Jones & Bartlett Learning, LLC © Jones & Bartlettgreatly influence Learning, local LLC environmental conditions for produce distinctive blade shapes and blade arrange- NOT FOR SALEother ORtypes DISTRIBUTION of shallow-water marine life by protect-NOT FORments SALE (Fig. 4.9 OR), yet DISTRIBUTION each begins as a young plant with ing them from waves and providing food, shade, and a single, unbranched, flat blade nearly identical to sometimes a substrate on which to attach and grow. other young kelp plants. The blades house photosynthetically active cells, Structural Features© of Jones Seaweeds & Bartlett Learning, LLCbut photosynthesis typically© Jones occurs &in Bartlettthe stipes andLearning, LLC Seaweeds are notNOT as complex FOR asSALE the flowering OR DISTRIBUTION plants. holdfasts as well. In cross-section,NOT FOR seaweed SALE ORblades DISTRIBUTION Seaweeds lack roots, flowers, seeds, and true leaves. (Fig. 4.10a) are structurally unlike the leaves of ter- Nevertheless, within these structural limitations, sea- restrial plants (Fig. 4.10b). The cells nearer the sur- weeds exhibit an unbridled diversity of shapes, sizes, face of the blade are capable of absorbing more light and© Jones structural & Bartlettcomplexity. Learning, Microscopic LLC filaments of and are photosynthetically© Jones & Bartlett more Learning, active than LLC those cells near the center of the blade. “Veins” of conduc- greenNOT and FOR brown SALE algae OR can DISTRIBUTION be found growing side by NOT FOR SALE OR DISTRIBUTION side with encrusting forms of red algae and flat sheet- tive tissue and distinctions between the upper and like members of all three divisions. The more obvi- lower surfaces are lacking in the blades of seaweeds. ous members of all three seaweed divisions typically Because the flexible blades either droop in the wa- develop into similar general forms, consisting of a ter, float erect, or are continuously tossed by turbu- © Jones & Bartlettblade, a stipe,Learning,and a holdfast LLC composed of many small© Joneslence, & Bartlett there is no Learning, defined upper LLC or lower surface. NOT FOR SALEfingerlike OR DISTRIBUTIONhaptera (Fig. 4.8). NOT FORThe twoSALE surfaces OR DISTRIBUTIONof the seaweed blade are usually exposed equally to sunlight, nutrients, and water The Blade and are therefore equally capable of carrying out The flattened, usually broad, leaflike structures of photosynthesis. Unlike seaweeds, flowering plants seaweeds are known© Jones as blades. & BartlettSeaweed blades Learning, often LLC(including seagrasses) exhibit© Jones an obvious & Bartlett asymme- Learning, LLC try of leaf structure, with a dense concentration of exhibit a complexNOT level FOR of branching SALE OR and DISTRIBUTION cellular NOT FOR SALE OR DISTRIBUTION photosynthetically active cells crowded near the upper surface (Fig. 4.10b). Below the upper epidermis and palisade mesophyll is a spongy layer of cells sep- arated by large spaces to enhance the exchange of © Jones & Bartlett Learning, LLC carbon dioxide,© Jones which & Bartlett is often 100Learning, times less LLC con- NOT FOR SALE OR DISTRIBUTIONBlade centratedNOT in air FOR than SALEin seawater. OR DISTRIBUTION Pneumatocysts Several large kelp species have gas-filled floats, or pneumatocysts, to buoy the blades toward the sun- © Jones & Bartlett Learning, LLC © Joneslight & at Bartlett the surface. Learning, Pneumatocysts LLC are filled with the

NOT FOR SALE OR DISTRIBUTION NOT FORgases SALE most abundant OR DISTRIBUTION in air, N2, O2, and CO2, although some kelp pneumatocysts also contain a few percent of carbon monoxide, CO. Again, there is a large diversity in size and structure. The largest pneumato- © Jones & Bartlett Learning, LLCcysts belong to Pelagophycus,© Jonesthe elkhorn & Bartlett kelp (Fig. Learning, LLC NOT FOR SALE OR DISTRIBUTION4.9). Each Pelagophycus plantNOT is FOR equipped SALE with OR a sin- DISTRIBUTION gle pneumatocyst, sometimes as large as a basketball, Stipe to support six to eight immense drooping blades, each of which may be 1 to 2 m wide and 7 to 10 m long. In strong contrast to Pelagophycus, Sargassum has Holdfast © Jones & Bartlett Learning, LLC numerous© smallJones pneumatocysts & Bartlett (Fig. Learning, 4.11). A few LLC species NOT FOR SALE OR DISTRIBUTION of SargassumNOTlead FOR a pelagic SALE life OR afloat DISTRIBUTION in the middle of the North Atlantic Ocean (the “Sargasso Sea”). In the Haptera Sargasso Sea, Sargassum creates large patches of float- Figure 4.8 ing plants that are the basis of a complex floating com- © Jones & BartlettThe northern Learning, sea palm Postelsia LLC(Phaeophyta) is equipped with a relatively© Jonesmunity & Bartlett of crabs, Learning, fishes, shrimp, LLC and other animals NOT FOR SALElarge stipeOR and DISTRIBUTION a massive holdfast. NOT FORuniquely SALE adapted OR toDISTRIBUTION living among the Sargassum. Large 106 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Egregia

Alaria

Some large kelp plants of temperate coasts.Each mature plant develops from a young plant with a single flat blade.

Cross-sections of a blade of a typical marine alga,Nereocystis (a),and a typical flowering plant leaf (b).Note the contrasting symmetry patterns.

© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION The Seaweeds 107 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. The Holdfast © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Holdfasts of the larger seaweeds often superficially NOT FOR SALE OR DISTRIBUTION NOT FORresemble SALE root OR systems DISTRIBUTION of terrestrial plants; however, the basic function of the holdfast is to attach the plant to the substrate. The holdfast seldom absorbs nutrients for the plant as do true roots. Holdfasts are adapted © Jones & Bartlett Learning, LLCfor getting a grip on the ©substrate Jones and & Bartlett resisting vio-Learning, LLC NOT FOR SALE OR DISTRIBUTIONlent wave shock and theNOT steady FOR tug of SALE tidal currents OR DISTRIBUTION and wave surges. The holdfast of Postelsia (Fig. 4.8), composed of many short, sturdy, rootlike haptera, illustrates one of several types found on solid rock. Other holdfasts are better suited for loose sub- © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC strates. The holdfast of Macrocystis has a large dif- NOT FOR SALE OR DISTRIBUTION fuse massNOT of haptera FOR SALE to penetrate OR DISTRIBUTION muddy or sandy Figure 4.11 bottoms and stabilize a mass of sediment for anchor- A portion of the floating brown alga,Sargassum, containing numerous small age (Fig. 4.12). Holdfasts of many smaller species do pneumatocysts,becomes a temporary home for a baby sea turtle. the same thing on a much smaller scale, with many © Jones & Bartlett Learning, LLC © Jonesfine & filaments Bartlett embedded Learning, in sand LLC or mud on the sea NOT FOR SALE OR DISTRIBUTION NOT FORbottom. SALE OR DISTRIBUTION masses of this plant community sometimes float ashore A variety of small red algae are epiphytes and on the U.S. East and Gulf Coasts, creating odor prob- demonstrate special adaptations for attaching them- lems for beachgoers as the dying plants decompose. selves to other marine plants. Figure 4.13 illustrates two common red algal epiphytes attached to a strand In the Sea of Japan,© other Jones species & Bartlett of attached Learning, intertidal LLC © Jones & Bartlett Learning, LLC of surf grass. Using other marine plants as substrates Sargassum break offNOT and FOR also become SALE free-floating OR DISTRIBUTION for NOT FOR SALE OR DISTRIBUTION extended periods of time. for attachment is a common habit of many smaller forms of red algae. The Stipe A flexible stemlike stipe connects the wave-tossed blades Photosynthetic Pigments of© seaweeds Jones &to theirBartlett securely Learning, anchored holdfastsLLC at the © Jones & Bartlett Learning, LLC bottom.NOT FOR An excellent SALE example OR DISTRIBUTION is Postelsia, the sea palm Each seaweedNOT FORdivision SALE is characterized OR DISTRIBUTION by specific (Fig. 4.8), which grows attached to rocks only in the combinations of photosynthetic pigments that are re- most exposed surf-swept portions of the intertidal zone. flected in their color and in the common name of each Its hollow resilient stipe is remarkably well suited for division (Table 4.1). The bright grass-green color of yielding to the waves without breaking. © Jones & BartlettThe bladesLearning, of some LLC seaweeds blend into the hold-© Jones & Bartlett Learning, LLC NOT FOR SALEfast without OR DISTRIBUTION forming a distinct stipe. In others, theNOT FOR SALE OR DISTRIBUTION stipe is very conspicuous and occasionally extremely long. The single long stipes of Nereocystis, Chorda, and Pelagophycus (Fig. 4.9) provide a kind of slack- line anchoring system© Jones and commonly & Bartlett exceed Learning, 30 m in LLC © Jones & Bartlett Learning, LLC length. The complexNOT multiple FOR stipesSALE of MacrocystisOR DISTRIBUTIONare NOT FOR SALE OR DISTRIBUTION often even longer. Special cells within the stipes of Macrocystis and a limited number of other brown and red algal species form conductive tissues strikingly similar in form to© thoseJones present & Bartlett in stems Learning, of terrestrial LLC plants. Radio- © Jones & Bartlett Learning, LLC activeNOT FORtracer SALE studies OR have DISTRIBUTION shown that these cells NOT FOR SALE OR DISTRIBUTION transport the products of photosynthesis from the blades to other parts of the plant. In smaller seaweeds, the necessity for rapid efficient transport Figure 4.12 © Jones & Bartlettthrough theLearning, stipe is minimal, LLC and such internal trans-© JonesComplex & Bartlett interlocking mass Learning, of haptera that makeLLC up the holdfast of NOT FOR SALEport isOR lacking. DISTRIBUTION NOT FORMacrocystis. SALE OR DISTRIBUTION 108 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Two red algal epiphytes:(a) Smithora and (b) Chondria attached to a leaf of Phyllospadix. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION green algae is due to the predominance of chlorophylls from the Gulf of California occasionally grows to 8 m over accessory pigments. Green algae vary in struc- in length. When compared with brown and red algae, ture from simple filaments to flat sheets (Fig. 4.14) and the Chlorophyta have fewer marine species, yet in diverse complex branching forms. They are usually some locations their limited diversity is compensated less than half a meter ©long, Jones but one & speciesBartlett of CodiumLearning,with LLC dense populations of individuals© Jones &from Bartlett one or Learning, LLC NOT FOR SALE OR DISTRIBUTIONtwo species. NOT FOR SALE OR DISTRIBUTION The photosynthetic pigments of the Phaeophyta sometimes appear as a greenish hue, but more often, the green of the chlorophyll is partially masked by the © Jones & Bartlett Learning, LLC golden xanthophyll© Jones pigments, & Bartlett especially Learning, fucoxanthin, LLC NOT FOR SALE OR DISTRIBUTION characteristicNOT of this FOR division. SALE This OR blend DISTRIBUTION of green and brown pigments usually results in a drab olive-green color (Fig. 4.15). Many of the larger and more familiar algae of temperate seas belong to this division. A number of species are quite large and are sometimes © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Figure 4.14 Figure 4.15 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR ASALE healthy growth OR of DISTRIBUTION the green alga Ulva lies on the sand during low tide. NOTThe FOR brown algaSALE Fucus growing OR on DISTRIBUTION a rocky intertidal shoreline. The Seaweeds 109 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. collectively referred to as kelp (Fig. 4.9). In temper- ble wavelengths. In addition, most green plants © Jones & Bartlett Learning, LLC © Jones & Bartlettate and high Learning, latitudes, LLCthese species usually dominate have chlorophyll b as well as chlorophyll a. Chloro- NOT FOR SALEthe marine OR DISTRIBUTION benthic vegetation. Numerous smaller,NOT FORphyll SALE b has a strongOR DISTRIBUTION light-absorbing peak in the blue less obvious brown algae are also common in temper- region of the visible spectrum and can collect a good ate and cold waters, as well as in tropical areas. fraction of the deep-penetrating blue light avail- Red algae, with red and blue phycobilin pigments, able in tropical waters. Still, red and brown algae, as well as chlorophyll,© Jones exhibit & Bartlett a wide range Learning, of col- LLCwith their abundant xanthophyll© Jones &and Bartlett phycobilin Learning, LLC ors. Some are brightNOT green, FOR such SALE as Porphyra OR DISTRIBUTION, the pop- pigments working in concertNOT with FOR chlorophyll, SALE OR gen- DISTRIBUTION ular seaweed known as nori that is used in sushi rolls, erally have a slight competitive advantage in occu- and others are sometimes confused with brown algae; pying the deeper portions of the photic zone in however, most red algae living below low tide range turbid coastal waters and function at no disadvan- tage in shallow waters or intertidal zones. in© color Jones from & softBartlett pinks toLearning, various shades LLC of purple © Jones & Bartlett Learning, LLC or red (Fig. 4.16). Red algae are as diverse in structure NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION and habitat as they are in coloration, and they seldom Reproduction and Growth exceed a meter in length. The adaptive significance of accessory photo- Reproduction in seaweeds, as well as in most other synthetic pigments for phytoplankton was described plants, can be either sexual, involving the fusion of © Jones & Bartlettin Chapter Learning, 3. At first glance,LLC it might appear that the© Jonessperm & Bartlett and eggs, Learning, or asexual, LLC relying on vegetative NOT FOR SALEgreen OR algae DISTRIBUTION and seagrasses, with their preponder-NOT FORgrowth SALE of new OR individuals. DISTRIBUTION Some seaweeds repro- ance of chlorophyll pigments, do not fare well at duce both ways, but a few are limited to vegetative moderate depths because of their limited ability to reproduction only. The pelagic species of Sargassum, absorb the deeper-penetrating green wavelengths for instance, maintain their populations by an irreg- of sunlight, but plants can adapt to low- or limited- ular vegetative growth followed by fragmentation © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC wavelength light conditions in other ways; for ex- into smaller clumps. The dispersed fragments of Sar- ample, because someNOT greenFOR algaeSALE have OR dense DISTRIBUTION con- gassum are capable of continuedNOT FOR growth SALE and ORregen- DISTRIBUTION centrations of chlorophyll that appear almost black, eration for decades. Sexual reproduction is lacking they are able to absorb light at essentially all visi- in the pelagic species of Sargassum but not in the attached benthic forms of the same genus. © Jones & Bartlett Learning, LLC Much© ofJones the structural & Bartlett variety Learning, observed LLCin sea- NOT FOR SALE OR DISTRIBUTION weeds isNOT derived FOR from SALE complex OR patterns DISTRIBUTION of sexual reproduction, patterns that define the life cycles of seaweeds. For our purposes, these complex life cycles can be simplified to three fundamental patterns. The sexual reproduction examples of the first two © Jones & Bartlett Learning, LLC © Jonestypes & describedBartlett Learning,here are not meantLLC to cover the en- NOT FOR SALE OR DISTRIBUTION NOT FORtire spectrum SALE OR of seaweed DISTRIBUTION life cycles but are used to illustrate the basic patterns that underlie the complexity and variation involved in sexual reproduction of seaweeds. © Jones & Bartlett Learning, LLC In the life cycle of most© Jones of the larger& Bartlett seaweeds, Learning, LLC NOT FOR SALE OR DISTRIBUTIONan alternation of sporophyteNOT and FOR gametophyte SALE OR gen- DISTRIBUTION erations occurs. The green alga Ulva represents one of the simplest patterns of alternating generations (Fig. 4.17). This basic life cycle is a hallmark of the kingdom Plantae. The cells of the macroscopic Ulva © Jones & Bartlett Learning, LLC sporophyte© Jones are diploid; & Bartlett that is, each Learning, cell contains LLC two NOT FOR SALE OR DISTRIBUTION of each NOTtype of FOR chromosome SALE OR characteristic DISTRIBUTION of that species. Some cells of the Ulva sporophyte undergo meiosis to produce single-celled flagellated spores. As a result of meiosis, these spores contain only one Figure 4.16 © Jones & Bartlett Learning, LLC © Joneschromosome & Bartlett of eachLearning, pair present LLC in the diploid sporo- NOT FOR SALECalcareous OR red DISTRIBUTION alga,Jania, in a small tide pool. NOT FORphyte SALE and are OR said DISTRIBUTION to be haploid. 110 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. There they immediately germinate by a series of mi- © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC totic cell divisions to produce a large, multicellular, sis NOT FOR SALE ORei oDISTRIBUTION NOT FOR SALE OR DISTRIBUTION M Haploid gametophyte generation that still is haploid. Cells of spores the gametophyte in turn produce haploid gametes, Germination each with two flagella, that are released into the water. When two gametes from different gametophyte © Jones & Bartlett Learning,individuals LLC meet, they fuse© to Jones produce & Bartletta diploid Learning, LLC NOT FOR SALE OR DISTRIBUTIONsingle-celled zygote. By repeatedNOT mitotic FOR divisions, SALE theOR DISTRIBUTION Diploid Haploid sporophyte gametophyte zygote germinates and completes the cycle by produc- plant plants ing a large, multicellular, diploid sporophyte once

G again. In Ulva, the sporophyte and gametophyte gen- e

r d m erations are identical in appearance. The only struc- e i v ©n Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC e a l t tural difference between the two forms is the number o io p n mNOT FOR SALE OR DISTRIBUTIONHaploid NOT FOR SALE OR DISTRIBUTION a of chromosomes in each cell; diploid sporophyte cells e n n d gametes t have double the chromosome number of haploid ga- Diploid metophyte cells. zygote The life cycles of numerous other seaweeds are © Jones & Bartlett Learning, LLC © Jonescharacterized & Bartlett by a suppression Learning, of LLCeither the gameto- NOT FOR SALE OR DISTRIBUTIONFusion NOTphyte FOR or theSALE sporophyte OR DISTRIBUTION generation. In the green alga Figure 4.17 Codium and the brown alga Fucus, the multicellular The life cycle of the green alga,Ulva, alternating between diploid sporophyte haploid generation is completely absent. The only hap- and haploid gametophyte generations.(Adapted from E.Y.Dawson. Marine loid stages are the gametes. In other large brown al- Botany of Marine Plants. Holt,Rinehart and Winston,1966.) gae, the gametophyte stage is reduced. The life cycle © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC of Laminaria is similar to that of most other large kelp NOT FOR SALE OR DISTRIBUTIONplants and serves as an excellentNOT generalized FOR SALE example OR DISTRIBUTION The spores of Ulva and other green algae each of seaweeds with a massive sporophyte that alternates have four flagella, whereas each gamete has two fla- with a diminutive gametophyte (Fig. 4.18). Special cells gella that are equal in length and project from one (called sporangia) on the blades of the diploid sporo- end of© theJones cell. Spores& Bartlett produced Learning, by Ulva areLLC capable phyte undergo© Jonesmeiosis to& produceBartlett several Learning, flagellated LLC of limitedNOT swimmingFOR SALE and OR then DISTRIBUTION settle to the bottom. microscopic NOTspores. FOR These SALE haploid OR spores DISTRIBUTION swim to the

Microscopic haploid male gametophyte Haploid spores © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Meiosis

Haploid sperm

L©arge Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC diploidNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION sporophyte n io s Fu G erm Egg inat ion a © Jones & Bartlett Learning, LLC nd development © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOTMicro FORscopic SALE OR DISTRIBUTION haploid female gametophyte

Figure 4.18 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR TheSALE life cycle OR of Laminaria DISTRIBUTION(similar to the cycles of other large kelps) alternates betweenNOT large FOR diploid sporophyteSALE andOR microscopic DISTRIBUTION haploid gametophyte generations. The Seaweeds 111 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. bottom and quickly attach themselves. They soon ger- division is commonly restricted to a few specific sites © Jones & Bartlett Learning, LLC © Jones & Bartlettminate into Learning, very small, LLCyet multicellular, gametophytes. within the plant that contain meristematic tissue NOT FOR SALEThe female OR DISTRIBUTION gametophyte produces large, nonflagel-NOT FORcapable SALE of further OR DISTRIBUTIONcell division. These meristems fre- lated eggs. The egg cells are fertilized in place on the quently occur at the upper growing tip of the plant. female gametophyte by flagellated male gametes, the In kelp plants and some other seaweeds, additional sperm cells produced by the male gametophyte. Af- meristems situated in the upper and lower portions ter fusion of the gametes,© Jones the & resulting Bartlett zygote Learning, germi- LLCof the stipe provide additional© Jones cells & to Bartlett elongate Learning,the LLC nates to form anotherNOT large FOR sporophyte. SALE ORThe flagellatedDISTRIBUTIONstipe and blades. The meristematicNOT FOR activity SALE of OR a cell DISTRIBUTION reproductive cells of brown algae always have two fla- layer near the outer stipe surface of some kelp species gella of unequal lengths, and they insert on the sides provides lateral growth to increase the thickness of of the cells rather than at the ends. the stipe. The stipes of a few perennial species of kelp, Red algae lack flagellated reproductive cells and including Pterygophora and Laminaria, retain evidence © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC are dependent on water currents to transport the male of this secondary lateral growth as concentric rings gametesNOT FOR to the SALE female OR reproductive DISTRIBUTION cells. The most that resembleNOT the FOR annual SALE growth OR rings DISTRIBUTION of trees. common life cycle of red algae has three distinct gen- In the spring, during periods of rapid growth, the erations, somewhat reminiscent of the reproductive rate of stipe elongation in large Nereocystis, Pelago- cycle outlined for Ulva (Fig. 4.17). A diploid sporo- phycus, and Macrocystis plants often exceeds 30 cm/day. © Jones & Bartlettphyte produces Learning, haploid LLC spores that germinate into© JonesMany & Bartlettkelp species Learning, produce kelpLLC blades resembling NOT FOR SALEhaploid OR gametophytes. DISTRIBUTION Instead of producing a newNOT FORmoving SALE belts ORof plant DISTRIBUTION tissue (Fig. 4.19), growing at the sporophyte, however, the gametes from the gameto- base and eroding or being eaten away at the tips. At phytes fuse and develop into a third phase unique to any one time, the visible plant itself (the standing red algae, the carposporophyte.The carposporophyte crop) may represent as little as 10% of the total then produces carpospores that develop into sporo- material it produced during a year. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC phytes, and the cycle is completed. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION The development of a large, multicellular seaweed Kelp Forests from a single microscopic cell (either a haploid spore or a diploid zygote) is essentially a process of repeated Most kelp plants are perennial. Although they may be mitotic cell divisions. Subsequent growth and differ- battered down to their holdfasts by winter waves, their entiation© Jones of &these Bartlett cells produce Learning, a complex LLC plant with stipes will© regrow Jones from & Bartlettthe holdfast Learning, for several succes-LLC manyNOT typesFOR of SALE cells, eachOR DISTRIBUTIONspecialized for particular sive seasons.NOT Thus, FOR the SALE extent OR of the DISTRIBUTION kelp canopy and functions. After the plant is developed, additional cell the overall three-dimensional structure of the kelp fordivision and growth occur to replace tissue lost to est are quite variable over annual cycles. Occasionally, animal grazing or wave erosion; however, such cell herbivore grazing or the pull of strong waves frees the © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Figure 4.19 © Jones & BartlettGeneralized Learning, growth pattern of aLLC kelp.Punched holes and dashed lines indicate© Jones the pattern of& blade Bartlett elongation.(Adapted Learning, from K.H.Mann, LLCMarine Biology NOT FOR SALE14(1973):199–209.) OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 112 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. holdfast and causes the plant to wash ashore. More of New England states and neighboring Canadian © Jones & Bartlett Learning, LLC © Jones commonly,& Bartlett small Learning, fragments LLC of blades and stipes are Maritime Provinces were scoured to bare rock (in NOT FORcontinually SALE OR eroded DISTRIBUTION away to decompose into food for NOTplaces FOR to SALEseveral hundredOR DISTRIBUTION meters below sea level) by detritus feeders. several episodes of continental glaciation. Only since Along most of the North American west coast, the retreat of the most recent glacial episode 8000 to subtidal rocky outcrops are cloaked with massive 10,000 years ago have these shores been recolonized, growths of several species© Jones of brown & Bartlettalgae, dominated Learning,and LLC that recolonization is not© yet Jones complete. & Bartlett Learning, LLC by either MacrocystisNOTor Nereocystis FOR SALE (Fig. 4.20OR). DISTRIBUTION West The lower species diversityNOT of northwesternFOR SALE At-OR DISTRIBUTION coast kelp forests occur as an offshore band parallel- lantic kelp beds leads to somewhat simpler trophic ing the coastline because wave action tears these interactions than those occurring in U.S. west coast plants out nearer to shore and light does not pene- kelp forests; still, similar species occupy the same trate to the sea floor farther offshore. In the dimmer major trophic roles (Fig. 4.22). The macroscopic © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC light below the canopy of these large kelps exists a primary producers are dominated by the kelp, shorterNOT understory FOR SALE of mixed OR brownDISTRIBUTION and red algae. Laminaria, withNOT an understoryFOR SALE of mixed OR DISTRIBUTIONred and brown Together, these large and small kelp plants accom- foliose algae. In clear patches below about 10 m, plish very high rates of primary production and sup- encrusting coralline red algae cover rock surfaces

port a complex community of grazers, suspension with a bright pink pavement of CaCO3. These coralline © Jones &feeders, Bartlett scavengers, Learning, and predatorsLLC (Fig. 4.21). From © Jonescrusts are & maintainedBartlett Learning, indirectly by LLC the constant graz- NOT FORCentral SALE California OR DISTRIBUTION northward, kelp abundance varies NOTing FOR actions SALE of sea OR urchins DISTRIBUTION on the larger kelp plants. seasonally, and the fishes are dominated by several On this coast, the lower limit of growth for Laminaria species of rockfishes in the genus Sebastes. In con- and other large kelps is controlled not by low light trast, southern California kelp forest abundance varies intensity as it is on the west coast but by the pres- irregularly and is especially vulnerable to the influence of grazing urchins. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ences of El Niño–Southern Oscillation events. Here, On the U.S. West coast, too, kelp beds exist in a the dominant fishesNOT are notFOR rockfishes; SALE OR instead, DISTRIBUTIONdelicate balance with their majorNOT grazers, FOR sea SALE urchins. OR DISTRIBUTION perches, damselfishes, and wrasses abound, reflect- Since World War II, kelp beds on both coasts have ing the more tropical affinities of these fishes. been devastated by dense aggregations of sea urchins Compared with the richness of species observed grazing on the holdfasts, causing the remainder of in western© Jones North & American Bartlett kelp Learning, forests, the LLC kelp beds the plant to break© Jones free and & washBartlett onto theLearning, shore. These LLC of theNOT northwestern FOR SALE Atlantic OR CoastDISTRIBUTION exhibit low di- large urchin NOTpopulations, FOR SALEcapable ORof completely DISTRIBUTION elim- versity in most taxonomic groups. Unlike the U.S. inating local kelp beds, seem free of the usual popula- west coast, the rocky intertidal and subtidal shores tion regulatory mechanisms—predation and starvation.

Feather Understory Laminaria boa kelp Shorter stipes, (Egregia) often close to © Jones & Bartlett Learning, LLC Pterygophora © Jones & Bartlett Learning, LLC bottom NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Bullwhip kelp (Nereocystis) Substrate Encrusting, clumping, or filamentous Giant kelp algae© Jones & Bartlett Learning,(Macrocystis) LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Elkhorn kelp (Pelagophycus) Offshore Inshore Figure 4.20 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR GeneralSALE structure OR of DISTRIBUTIONa U.S.west coast kelp forest,with a complex understory of plantsNOT beneath FOR the dominant SALE Macrocystis OR DISTRIBUTIONor Nereocystis. The Seaweeds 113 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC Octopus Sea otter© Jones Sea& Bartlett star Learning,Sheephead LLC Predators NOT FOR SALE OR DISTRIBUTION (Octopus) (Enhydra)NOT FOR(Pisaster) SALE OR(Semicossyphus) DISTRIBUTION

Lobster Whelk Scavengers (Panulirus) (Kelletia) © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Suspension Sea squirt Mussel feeders (Styela) (Mytilus)

Detritus pool © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Brown and red algae Figure 4.21

Trophic relationships of some dominant members of a southern California kelp community. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Predators and Lobster Eelpout Sea star Crab scavengers (Homarus) (Macrozoarces) (Asterias) (Cancer) © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Suspension Tunicate Mussel feeders (Molgula) (Modiolus)

Snail Limpet Sea urchin © Jones & Bartlett Learning, LLCGrazers (Littoraria) © Jones(Acmaea) & Bartlett(Strongylocentrotus) Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Detritus pool © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONFoliose brown and coralline red algae NOT FOR SALE OR DISTRIBUTION

Figure 4.22

Trophic relationships of the common members of a New England kelp community. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION A major predator of West Coast kelp bed urchins is the perienced major population reductions in the past sea otter (Enhydra, see Fig. 7.13). East Coast sea urchins 2 centuries. are similarly preyed on by the lobster (Homarus); how- Available evidence indicates that the effects of © Jones & Bartlettever, both Learning, of these predators LLC have been subjected© Jonesthis & reduced Bartlett predation Learning, have LLC been magnified by NOT FOR SALEto intensive OR DISTRIBUTION commercial harvesting and have ex-NOT FORincreased SALE concentrations OR DISTRIBUTION of dissolved and suspended 114 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. organic materials in coastal waters (mostly from ur- States. Standard secondary treatment of sewage is in- © Jones & Bartlett Learning, LLC © Jones ban& Bartlett sewage outfalls). Learning, The LLCU.S. Office of Technology tended to separate solids and to reduce the amount NOT FORAssessment SALE OR has DISTRIBUTION identified over 1300 major indus- NOTof organicFOR SALE matter OR (which DISTRIBUTION contributes to biochemical tries and 600 municipal wastewater treatment plants oxygen demand), nutrients, pathogenic bacteria, toxic that discharge into the coastal waters of the United pollutants, detergents, oils, and grease in wastewater. In the United States, most ocean discharges of © Jones & Bartlett Learning,wastewater LLC are supposed to© meet Jones those & secondary Bartlett Learning, LLC 100 NOT FOR SALE OR DISTRIBUTIONtreatment standards, but manyNOT still FORdo not, SALE including OR DISTRIBUTION some that discharge into southern California coastal Changed habitat waters. Until the mid 1980s, treated sewage contain-

Degraded habitat ing about a quarter of a million tons of suspended 75 solids was discharged from 4 large and 15 small pub- © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC licly owned sewage treatment plants each day. These NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

2 solids are similar to detritus from natural marine 50 sources in its general composition and nutritional value for zooplankton and benthic detritus feeders.

Area, km Measurable changes in species diversity and biomass © Jones & Bartlett Learning, LLC © Jonesof benthic & Bartlett infauna and Learning, kelp beds LLC can be found, but NOT FOR SALE25 OR DISTRIBUTION NOTthese FOR changes SALE depend OR onDISTRIBUTION the rate of discharge and the degree of treatment before release. Increased abundance of fishes and benthic invertebrates have been noted in the vicinity of some outfalls; at others, ben- 0 thic communities have been noticeably degraded. Of Los Angeles© Los Jones Angeles &Orange BartlettSan Learning,Diego LLC © Jones & Bartlett Learning, LLC County County the four major sewer outfalls emptying into the South- Figure 4.23 NOT FOR SALE OR DISTRIBUTIONern California Bight, two hadNOT caused FOR obvious SALE degra- OR DISTRIBUTION Extent of areas changed or degraded by four major sewage outfalls in the dation in several square kilometers around the outfall California Bight,1978–1979.(Data from A.J.Mearns.Marine Environmental site (Fig. 4.23). Collectively, the four outfalls signifi- Pollution, Elsevier,1981.) cantly changed or degraded nearly 200 km2 of seafloor © Jones & Bartlett Learning, LLC during the 1970s© Jones and 1980s. & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION These energy-richNOT FOR substances SALE fromOR DISTRIBUTIONtreated sewage enabled urchin populations to evade the usual conse- quences that befall animal populations when they over- graze their plant food sources. These alternative sources of energy ensured that large numbers of urchins sur- © Jones & Bartlett Learning,150 LLC Los Angeles © Jonesvived long& Bartlett enough afterLearning, decimating LLC one kelp bed to NOT FOR SALE OR DISTRIBUTION100 NOT FORmove SALE to another. OR DISTRIBUTIONIn central California kelp beds

TSS 50 Los Angeles County 0 Orange County that sea otters have recolonized since 1950, 80 85 90 95 00 Total suspended solids, Year urchin populations are now kept low, and 1000 metric tons/day kelp forests have recovered throughout most of the otters’ geographic range. The © Jones &150 Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR100 SALE OR DISTRIBUTION kelp beds just NOToff San FOR Diego, SALE however, OR DISTRIBUTION TSS 50 have made a dramatic recovery since 0 80 85 90 95 00 San Diego 1960 without sea otters. The recov- Year ery there was more likely due to im- proved urban sewage treatment, © Jones & Bartlett Learning, LLC © Jonesespecially & Bartlett reducing Learning, the amounts LLC of NOT FOR SALE OR DISTRIBUTION NOT FORdischarged SALE solids OR (DISTRIBUTIONFig. 4.24). The activities of other predators, particularly sea stars and the California Figure 4.24 sheephead, also played important © Jones &Graphs Bartlett showing theLearning, reduction in discharged LLC total suspended solids (TSS) for the© past Jones two decades & at theBartlettroles. Learning, In an unusual LLC turnabout, NOT FOR fourSALE major sewage OR outfallsDISTRIBUTION in the California Bight.(Data from Steinberger and Schiff,2002.)NOT FOR SALE ORthese DISTRIBUTION recovered urchin populations, The Seaweeds 115 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. so recently considered pests in need of eradication, are Africa, and the western side of Central America, sea- © Jones & Bartlett Learning, LLC © Jones & Bartlettnow themselves Learning, targets LLC of a rapidly expanding com- weeds thrive in profusion along the coasts of south- NOT FOR SALEmercial OR fishery DISTRIBUTION to supply urchin roe to local and inter-NOT FORern Australia SALE OR and DISTRIBUTIONSouth Africa, on both sides of the national sushi markets. North Pacific, and in the Mediterranean Sea. The U.S. West Coast is somewhat richer in seaweed diversity than is the East Coast. From Cape Cod northward, © Jones &SUMMARY Bartlett Learning,POINTS LLCthe East Coast is populated© Joneswith subarctic & Bartlett seaweeds. Learning, LLC NOT FOR SALE OR DISTRIBUTIONSouth of Cape Cod, theNOT effects FOR of the SALE warm OR Gulf DISTRIBUTION The Seaweeds Stream become more evident, until a completely trop- • Most large conspicuous plants in the sea are ical flora is encountered in southern Florida. macroalgae (seaweeds and kelps), growing Red algae are not rare in cold-water regions but from rocky or sandy substrates with their char- are more abundant and conspicuous in the tropics © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC acteristic blades, stipes, holdfasts, and pneu- and subtropics. Calcareous forms of red algae (and NOTmatocysts FOR SALE (in some OR species). DISTRIBUTION some brownsNOT and FOR greens SALE as well) OR are DISTRIBUTION characterized by

• The common names of seaweeds often are extensive deposits of calcium carbonate (CaCO3) motivated by their colors, which in turn reflect within their cell walls. The use of calcium carbonate the various photosynthetic pigments that they as a skeletal component by warm-water marine algae © Jones & Bartlettcontain. Learning, Just as in LLC phytoplankton, there is adap-© Jonesis apparently & Bartlett related Learning, to the decreasedLLC solubility of

NOT FOR SALE tiveOR significance DISTRIBUTION for all accessory photopigmentsNOT FORCaCO SALE3 in water OR at DISTRIBUTION higher temperatures. In the trop- possessed by seaweeds. ics, plants expend less energy to extract CaCO3 from • Reproduction in seaweeds can be either veg- the water, and here, coralline red algae contribute etative and asexual or complex and sexual. to the formation and maintenance of coral reefs. Sexual reproduction tends to follow three fun- Encrusting coralline algae grow over coral rubble, ce- © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC damental patterns, all variations of alternating menting and binding it into larger masses that better sporophyte,NOT gametophyte, FOR SALE and/or ORcarposporo- DISTRIBUTIONresist the pounding of heavyNOT surf. FOR Some SALE Indian OR Ocean DISTRIBUTION phyte generations. “coral” reefs completely lack coral animals and are • Luxurious kelp communities dominate in tem- constructed and maintained entirely by coralline al- perate areas, with North America’s west coast gae. The few calcareous forms of green algae that ex- © Joneshosting & a Bartlett more complex Learning, and extensive LLC kelp ist are also© limitedJones to & tropical Bartlett latitudes Learning, and play LLC a large NOTcommunity FOR SALE than ORNew DISTRIBUTION England. role in theNOT production FOR SALE of CaCO OR3 sediments. DISTRIBUTION The small green alga Halimeda is one of the few

green algae to also secrete a CaCO3 skeleton, giving it a stony feel. Halimeda is a member of a remarkable group of Chlorophytes known as siphonous green © Jones & Bartlett Learning,Geographic LLC Distribution © Jonesalgae. & BartlettAlthough Learning,some siphonous LLC green algae reach NOT FOR SALE4.3 ORThe DISTRIBUTION interplay of a multitude of physical,NOT FORseveral SALE meters OR in DISTRIBUTION size, each plant consists of an chemical, and biological variables influences and con- enormously long, tubular, single cell containing trols the distribution of marine plants on a local scale. millions of nuclei by uncoupling the process of nuclear For instance, on an exposed rock in the lower inter- division from that of cell division. Two other members tidal zone on the ©Oregon Jones coast, & Bartlett Postelsia mayLearning, thrive, LLCof this group, Caulerpa taxifolia© Jonesand Codium & Bartlett fragile, Learning,re- LLC but 10 m away, theNOT conditions FOR SALE of light, OR temperature, DISTRIBUTIONcently have become notoriousNOT FORfor their SALE explosively OR DISTRIBUTION nutrients, tides, surf action, and substrate may be rapid invasions as introduced exotics, Caulerpa in the such that Postelsia cannot survive. Nevertheless, on Mediterranean Sea (Fig. 4.25) and Codium in shallow an ocean-wide scale, only a few factors seem to con- coastal waters of New Zealand and the U.S. Northeast. trol the presence or absence of major groups of sea- These invasions have been enhanced by the ability of weeds.© Jones Significant & Bartlett among Learning, these are LLCwater and air these plants© Jones to fragment & Bartlett in storms Learning, and quickly LLCregrow temperature,NOT FOR SALE tidal amplitude, OR DISTRIBUTION and the quality and from theNOT wave-scattered FOR SALE pieces. OR DISTRIBUTION quantity of light. With these factors in mind, we can A few of the larger species of benthic marine plants make a few generalizations concerning the geographic flourish in such profusion that they dominate the gen- distribution of benthic plants. eral biological character of their communities. Such © Jones & BartlettIn marked Learning, contrast LLC to the impoverished seaweed© Jonescommunity & Bartlett domination Learning, by plants LLC is common on land NOT FOR SALEflora ORof the DISTRIBUTION Red Sea, the tropical western coastNOT of FORbut is SALE exceptional OR inDISTRIBUTION the sea. Away from the near-shore 116 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

A dense growth of Caulerpa has invaded the Mediterranean Sea. A kelp forest off the California coast,dominated by Macrocystis, a brown alga.

habitats© Jones occupied & byBartlett benthic Learning,plants, the microscopic LLC sea surface, ©create Jones substantial & Bartlett drag againstLearning, currents LLC phytoplanktonNOT FOR prevail SALE as the OR major DISTRIBUTION primary producers and swells andNOT are FOR susceptible SALE to OR storm DISTRIBUTION damage by of the sea, and it is their larger animal consumers that waves and surge. Cast on the shore, these decaying define the visual character of their pelagic communi- plants are a major food source for beach scavengers. ties. In the near-shore fringe, however, mangals, salt marshes, seagrasses, and kelp beds thrive where the ap- © Jones &propriate Bartlett bottom Learning, conditions, LLC light, and nutrients exist. © Jones & Bartlett Learning,SUMMARY LLC POINTS NOT FOR SALEKelp ORare temperate DISTRIBUTION to cold-water species, with NOT GeographicFOR SALE Distribution OR DISTRIBUTION few tropical representatives. Large kelps are especially abundant in the North Pacific. Kelp beds abound with • A complex interplay of a multitude of physical, chemical, geological, and biological factors de- herbivores that graze directly on these plants and in termines the distribution of marine plants on turn become prey for higher trophic levels. The cool- © Jones & Bartlett Learning, LLCboth small and large scales.© Jones & Bartlett Learning, LLC water kelp plants form extensive layered forests of NOT FOR SALE OR DISTRIBUTION• A knowledge of these variablesNOT FOR helps SALE one un- OR DISTRIBUTION mixed species in both the Atlantic and Pacific Oceans. derstand why opposite sides of an intertidal The blades of the larger Macrocystis, Laminaria, or rock or an entire continent may host different Nereocystis form the upper canopy and the basic struc- species of plants. ture of these plant communities. Shorter members of other© brown Jones algal & Bartlettand red algal Learning, species provide LLC sec- © Jones & Bartlett Learning, LLC ondaryNOT understory FOR SALE layers andOR createDISTRIBUTION a complex three- NOT FOR SALE OR DISTRIBUTION dimensional habitat with a large variety of available Seasonal Patterns of Marine niches (Fig. 4.26). The maximum depth of these kelp Primary Production beds, usually 20 to 30 m, is limited by the light avail- 4.4 In Chapter 3, the influence of sunlight, nu- © Jones &able Bartlett for the youngLearning, growing LLC sporophyte. The larger © Jonestrients, &and Bartlett grazers onLearning, marine primary LLC productivity NOT FORkelp SALE plants, OR with DISTRIBUTION their broad blades streaming at the NOTwas FOR considered. SALE Here OR weDISTRIBUTION put it all together to develop Seasonal Patterns of Marine Primary Production 117 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. a dynamic coherent picture of how marine primary outlines the major links between factors involved in © Jones & Bartlett Learning, LLC © Jones & Bartlettproductivity Learning, patterns change LLC over seasonal time scales defining the actual pattern of net primary produc- NOT FOR SALEand oceanic OR DISTRIBUTION distances. The numbers needed NOTfor FORtion (NPP)SALE through OR DISTRIBUTION time. With these in mind, we can this summary are difficult to come by and are chang- develop some general pictures of the seasonal pat- ing as new techniques for measuring marine primary tern of primary production for several different ma- productivity are developed. Since the first edition of rine production systems. this text was written,© Jones estimates & Bartlett of global marineLearning, pri- LLC © Jones & Bartlett Learning, LLC mary productivityNOT have approximately FOR SALE doubled, OR DISTRIBUTION thanks Temperate Seas NOT FOR SALE OR DISTRIBUTION in large part to satellite monitoring systems such as Figure 4.28 the sea-viewing wide field-of-view sensor (SeaWiFS) depicts a somewhat idealized graphic sum- described in Chapter 3. Globally, the marine plants mary of major physical, chemical, and biological events in temperate oceanic areas well away from the described in this chapter account for only about 2% © Jones & Bartlett Learning, LLC influences© Jonesof coastlines. & Bartlett These areasLearning, include LLC broad of each year’s total marine primary productivity; phy- swaths of midlatitude open ocean as well as locally toplanktonNOT FOR take SALE care ofOR the DISTRIBUTION rest. Thus, again, the em- NOT FOR SALE OR DISTRIBUTION defined areas such as the Grand Banks of the North phasis of the following discussion is on phytoplankton. Atlantic Ocean. These temperate oceanic systems The spatial patchiness of marine primary pro- are characterized by wintertime convective mixing duction described in Chapter 3 is related on large between surface and deep layers. scales to areas of nutrient abundance and on much © Jones & Bartlett Learning, LLC © Jones &A Bartlettprominent Learning, feature in the LLC production cycle of smaller scales to the local influences of grazers, near- NOT FOR SALE OR DISTRIBUTION NOT FORtemperate SALE seas OR is aDISTRIBUTION spring diatom population explo- surface turbulence, and nutrient patches. Seasonal sion, or diatom bloom. Diatom blooms are the result variations, or patchiness in time, occur in response of combined seasonal variations of water tempera- to changes in light intensity, nutrient abundance, and ture, light and nutrient availability, and grazing in- grazing pressure. The underlying pulse for these time © Jones & Bartlett Learning, LLCtensity. In early spring, water© Jonestemperature & Bartlett and available Learning, LLC changes is the predictable seasonal variation in the in- NOT FOR SALE OR DISTRIBUTIONlight increase, nutrients areNOT abundant FOR SALEin near-surface OR DISTRIBUTION tensity of sunlight reaching the sea surface. Figure 4.27 waters, and grazing pressure is diminished. As soon as the minimum threshold level of sunlight needed Abiotic factors Biotic factors for photosynthesis is achieved, conditions are ideal for rapid and abundant growth of primary producers. Sea surface © Jones light& Bartlett intensity Learning, LLC If the bottom© Jones of the & mixed Bartlett layer Learning, extends below LLC the NOT FOR SALE OR DISTRIBUTION compensationNOT FORdepth SALE(determined OR DISTRIBUTION by light penetra-

Heat Light tion, see Fig. 3.20), near-surface turbulence will dis- tribute the phytoplankton cells randomly throughout Water Photosynthetic temperature rates the mixed layer, and primary production will remain low. Cells in the deeper portions of the mixed layer © Jones & Bartlett Learning, LLC © Jonesreceive & Bartlett insufficient Learning, light, and LLCno net production will NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Water occur. The spring bloom will commence only after density the thermocline thins the mixed layer to a level above

Phytoplankton the compensation depth. In general, bloom condi- production tions in the open ocean occur as a broad band of pri- Vertical © Jones & Bartlett Learning, LLCmary production sweeping© poleward Jones from & Bartlett midlatitudes Learning, LLC mixing NOT FOR SALE OR DISTRIBUTIONin both hemispheres withNOT the FORonset SALEof spring. OR The DISTRIBUTION standing crop of diatoms increases quickly to the largest of the year and begins to deplete nutrient con- Nutrient Herbivore centrations. The grazers respond to the additional for- availability production age by increasing their numbers. © Jones & Bartlett Learning, LLC As spring© Jones warms & into Bartlett summer, Learning, sunlight becomes LLC NOT FOR SALE OR DISTRIBUTION more plentiful,NOT FOR but the SALE now stronglyOR DISTRIBUTION developed sea- Figure 4.27 sonal thermocline effectively blocks nutrient return The seasonal variation of light intensity at the sea surface sets in motion a from deeper water. The now warmer waters are “older” cascading series of changes in the photic zone.Eventually,these factors surface waters, with most of their dissolved nutrients © Jones & Bartlettinfluence primary Learning, production,either LLC directly (solid arrows) or through © Jonesdepleted. & Bartlett Coupled Learning, with increased LLC grazing, the diatom NOT FOR SALEfeedback OR links DISTRIBUTION (dashed arrows). NOT FORpopulation SALE peaks OR andDISTRIBUTION then declines and remains low 118 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION SeaNOT surface FOR SALE OR DISTRIBUTION Sea surface temperature light intensity

Depth of mixed layer

Zooplankton © Jones & Bartlettstanding Learning, crop LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Net photosynthesis

Seasonal fluctuations in the major features of a primary production system in temperature latitudes of the sea.

© Jones &throughout Bartlett theLearning, summer. WithLLC food more scarce, the © Jonesdeeper in& theBartlett photic zoneLearning, may supplement LLC their mea- NOT FORsummer SALE zooplanktonOR DISTRIBUTION population also drops. Unlike NOTger FOR nutrient SALE supply OR by DISTRIBUTION migrating downward a few diatoms, dinoflagellate populations increase slowly meters during night hours to soak up additional nu- during the spring, remain healthy throughout the trients from slightly deeper water. summer (although not as abundant as diatoms are in Cooler autumn air temperatures begin to break spring), and decline in© autumn Jones because & Bartlett of diminished Learning,down LLC the summer thermocline© andJones allow & convection Bartlett Learning, LLC light intensity. NOT FOR SALE OR DISTRIBUTIONto renew nutrients in the photicNOT zone. FOR The phytoplank- SALE OR DISTRIBUTION This replacement of diatoms by dinoflagellates ton respond with another bloom, which, although not is a form of seasonal succession resulting from some as remarkable as the spring bloom, is often sufficient basic ecological differences between the two princi- to initiate another upswing of the zooplankton pop- pal groups of phytoplankton. Recall that diatoms lack ulation. As winter approaches, the autumn bloom is flagella,© Jones cannot &swim, Bartlett are more Learning, readily inhibited LLC in cut short by© decreasing Jones & light Bartlett and reduced Learning, tempera- LLC high-lightNOT intensities,FOR SALE perform OR DISTRIBUTION better in low-light in- tures. As productionNOT FOR goes SALE down, OR resistant DISTRIBUTION overwin- tensities, and have a nutrient need for silicate. These tering stages of both phytoplankton and zooplankton features give diatoms a competitive advantage in less- become more abundant. Convective mixing contin- well-lit, colder, denser, nutrient-rich waters and di- ues to recharge the nutrient load of the surface waters © Jones &noflagellates Bartlett theLearning, advantage LLC in warmer better-lit waters © Jonesin readiness & Bartlett for a repeat Learning, of the entire LLC performance the NOT FORthat SALE may beOR deficient DISTRIBUTION in silicate. Some dinoflagellates NOTfollowing FOR SALE spring. ORIt is nowDISTRIBUTION estimated that, on average, Seasonal Patterns of Marine Primary Production 119 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. about 206 g C/m2 per year is produced in oceanic Coastal Upwelling © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC temperate and subpolar areas, with most of that total NOT FORCoastal SALE upwelling OR DISTRIBUTION in temperate seas alters the NOT FOR SALEoccurring OR DISTRIBUTIONduring the spring diatom bloom. generalized picture presented in Figure 4.28 by Warm Seas replenishing nutrients during the summer, when they would otherwise be depleted. As long as light is suffi- The production characteristics of tropical and sub- cient and upwelling continues, high phytoplankton © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC tropical oceanic waters closely resemble those of con- production occurs and is reflected in abundant local tinuous summer NOTin temperate FOR SALEregions, OR as outlined DISTRIBUTION in animal populations (Fig. NOT4.30). InFOR some SALE areas, theOR du- DISTRIBUTION Figure 4.28. Sunlight is available in abundance, yet ration and intensity of coastal upwelling fluctuate with NPP is low (about 55 g C/m2 per year) because a variations in atmospheric circulation. Along the Wash- strong permanent pycnocline blocks vertical mixing ington and Oregon coasts, the variability of spring and of© nutrients Jones &from Bartlett below. TheLearning, low rate LLCof nutrient re- summer ©wind Jones patterns & Bartlett produces Learning,sporadic upwelling LLC turnNOT is FORpartially SALE compensated OR DISTRIBUTION for by a year-round interspersedNOT with FOR short SALE periods OR of DISTRIBUTIONno upwelling and growing season and a deep photic zone. Even so, NPP lower NPP. Coastal upwelling zones have average NPP and standing crops are low (Fig. 4.29), and dinofla- rates approaching 1050 g C/m2 per year (Fig. 4.31). In gellates are usually more abundant than diatoms. the Peru Current, upwelling is massive year round Regions of upwelling in the equatorial Pacific and, and is interrupted only by major disturbances such © Jones & Bartlettto a lesser Learning, extent, the equatorial LLC Atlantic are more pro-© Jonesas El & Niño Bartlett events. Learning, LLC NOT FOR SALEductive OR than DISTRIBUTION tropical open ocean areas, but they NOTare FOREl SALE Niño is OR a phenomenon DISTRIBUTION that represents a strong very limited in geographic extent (see Fig. 3.37). So departure from the more typical current patterns in too are coral reef communities, with annual NPP rates the central Pacific Ocean (see Fig. 1.37) that drive up to 5000 g C/m2 per year. Upwelling is described coastal and equatorial upwellings. El Niño is char- in the next section,© andJones the reasons & Bartlett for exceptionally Learning, LLCacterized by a prominent© warming Jones of& theBartlett equatorial Learning, LLC high productivity rates on coral reefs are discussed in Pacific surface waters. El Niño occurs irregularly Chapter 10. NOT FOR SALE OR DISTRIBUTIONevery few years, and eachNOT occurrence FOR SALE lasts OR from DISTRIBUTION

Figure 4.29 © Jones & BartlettSeaWiFS image Learning, of chlorophyll aLLCconcentrations in the area off the U.S.East© Coast,taken Jones on May& 11,2002.TheBartlett color Learning, bar is the same as LLC those shown in other SeaWiFS NOT FOR SALEimages OR in Chapter DISTRIBUTION 3. Note the increase in net primary production (NPP) withNOT latitude. FOR SALE OR DISTRIBUTION 120 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Increasing productivity

Tropical Temperate coastal upwelling Subpolar Temperate Figure 4.30 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR ComparisonSALE ofOR the generalDISTRIBUTION patterns of seasonal variations in primary productivityNOT for four differentFOR marineSALE production OR systems. DISTRIBUTION

Figure 4.31

SeaWiFS image of chlorophyll a concentrations in the upwelling area of the California Current (left) and the Benguela Current off South Africa and Namibia (right). Note the pulse of high phytoplankton© Jones production & off Bartlett California being Learning, transported well offshore.The LLC color designation is the same as© that Jones in other SeaWiFS & Bartlett images in Learning, LLC this chapter and Chapter 3. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

several months to well over a year. The El Niño phe- water westward, the water is warmed, and the ther- nomenon is associated with the Southern Oscilla- mocline is depressed from about 50 m below the sur- tion,© a trans-PacificJones & Bartlett linkage ofLearning, atmospheric LLC pressure face on the ©east Jones side of & the Bartlett Pacific toLearning, about 200 LLC m systems,NOT and FOR the SALEclimatic OR anomaly DISTRIBUTION has come to be deep on the NOTwest side. FOR ENSOs SALE occur, OR forDISTRIBUTION reasons not known collectively as El Niño/Southern Oscillation, yet understood, when this pressure difference across or ENSO. Normally, the trade winds blow around the tropical Pacific relaxes and both surface winds the South Pacific high pressure center located near and ocean currents either cease to flow westward © Jones &Easter Bartlett Island Learning, and then blow LLC westward to a large In- © Jonesor actually & Bartlett reverse themselves. Learning, Although LLC the effects NOT FORdonesian SALE ORlow-pressure DISTRIBUTION center. As these winds move NOTof anFOR ENSO SALE event OR are DISTRIBUTION somewhat variable, they are Seasonal Patterns of Marine Primary Production 121 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. usually global in extent and occasionally severe in (2009–2010) is gaining strength and very well may © Jones & Bartlett Learning, LLC © Jones & Bartlettimpact. Learning, LLC replace the 2002–2004 episode on the top 10 list of NOT FOR SALEThe OR 1982–1983 DISTRIBUTION ENSO event, for example, wasNOT FORENSO SALE events OR during DISTRIBUTION the last half century. associated with heavy flooding on the West Coast of the United States, intensification of the drought Polar Seas in sub-Saharan Africa and Australia, and severe hurricane-force storms© Jones in Polynesia. & Bartlett Surface Learning, ocean LLCThe two polar ends of the© Jones Earth share & Bartlett several Learning,en- LLC water temperaturesNOT from FOR Peru SALE to California OR DISTRIBUTION soared vironmental characteristicsNOT that FOR distinguish SALE OR them DISTRIBUTION to as much as 8°C above normal. The 1997–1998 from other marine environments. Both experience ENSO event caused similar disruptions but was long winter nights without sunlight. Low levels of even more severe (Fig. 4.32). These strong El Niño sunlight keep sea surface temperatures hovering events© Jones and &the Bartlett associated Learning, buildup ofLLC warm, less- around 0°C,© Jones even in& summer.Bartlett LargeLearning, parts of LLC both denseNOT waterFOR blocksSALE upwelling OR DISTRIBUTION of nutrient-rich wa- polar marineNOT environments FOR SALE remain OR DISTRIBUTION perpetually cov- ters, and coastal marine populations decline. Dur- ered by permanent sea ice known as fast ice. Even ing severe El Niño years, some fishes and fish-eating larger areas freeze over in winter to form pack ice seabird populations almost completely disappear. that thaws and disappears each summer. Polar seas Eventually, the area of warm tropical water dissipates, are defined as those areas of the ocean character- © Jones & Bartlettand El Niño Learning, conditions LLC are replaced by cooler east-© Jonesized & by Bartlett a cover ofLearning, either permanent LLC fast ice or sea- NOT FOR SALEern tropical OR DISTRIBUTION Pacific surface temperatures, low rain-NOT FORsonal SALE pack ice. OR The DISTRIBUTION approximate geographic extent fall, and well-developed coastal upwelling along of fast and pack ice is shown in Figure 4.33. Sea ice Peru and northern Chile. is a solid physical structure encountered in no other Unfortunately, ENSO events continue to recur. marine ecosystem. It acts as a barrier to insulate sea- The 2002–2004 ©episode Jones is ranked& Bartlett in the Learning, top 10 El LLCwater from continued chilling© Jones effects & Bartlettof the atmos- Learning, LLC Niño events of theNOT last FOR 50 years. SALE A similar OR DISTRIBUTION El Niño phere in winter, and thus,NOT sea FORice never SALE more OR than DISTRIBUTION event appeared in 2006 but it had an unusually short a few meters thick forms in even the most extreme duration, collapsing in early 2007. As this edition is winter temperature regimes. Sea ice also provides a being prepared, the most current El Niño event stable and nearly predator-free platform on which © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 0 20N 0

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–2 –1.5 –1 –0.5 0.5 1 1.5 2 3 45 Figure 4.32 © Jones & BartlettObserved sea Learning, surface temperature LLC anomaly,in degrees Celsius,in the Equatorial© Jones Pacific Ocean & based Bartlett on a 7-day Learning,average in mid-September LLC 1997.Notice the tongue NOT FOR SALEof unusually OR warmDISTRIBUTION water extending westward from the coasts of Ecuador andNOT Peru. FOR SALE OR DISTRIBUTION 122 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. Winter (January) North Polar Region Summer (July) © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Summer (January) South Polar Region Winter (July) © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

Figure© Jones 4.33 & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Approximate distribution of fast ice (summer) and pack ice (winter) in the north and south polar regions.

some birds and mammals can raise their young (see the complete cycle of production consists of a sin- © Jones &Chapter Bartlett 7), yetLearning, it also effectively LLC bars many of those © Jonesgle short & periodBartlett of phytoplankton Learning, LLC growth, equiva- NOT FORsame SALE animals OR DISTRIBUTIONfrom moving easily from the ice sur- NOTlent FOR to a typicalSALE spring OR DISTRIBUTION bloom immediately followed face to forage the water below. The thermocline, if by an autumn bloom and decline that alternates with one exists at all, is poorly established and its asso- an extended winter of reduced net production. In ciated pycnocline is not an effective barrier to ver- both the Arctic Ocean and around the Antarctic con- tical movements of water and nutrient regeneration tinent, the seasonal formation and melting of sea © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC in the photic zone. Light, or more correctly the lack ice play a central role in shaping patterns of primary of it, is the major limitingNOT FORfactor SALE for plant OR or DISTRIBUTION phy- productivity. As ice melts in theNOT spring, FOR the SALE low salin- OR DISTRIBUTION toplankton growth in polar seas. Sufficient light to ity meltwater forms a low-density layer near the sea sustain high phytoplankton growth rates lasts for surface. This increases vertical stability, which encour- only a few months during the summer. Even so, ages phytoplankton to grow near the sunlit surface. photosynthesis© Jones &can Bartlett continue Learning, around the LLCclock dur- The melting© ice Jones also releases & Bartlett temporarily Learning, frozen phy- LLC ing thoseNOT few FOR months SALE to produceOR DISTRIBUTION huge phytoplank- toplankton NOTcells, orFOR ice algae,SALE into OR the DISTRIBUTION water to ini- ton populations quickly. As the light intensity and tiate the bloom. The individual phytoplankton cells day length decline, the short summer diatom bloom produced in these summer blooms tend to be much declines rapidly. Winter conditions closely resem- larger than those in lower latitudes. These in turn feed © Jones &ble Bartlett those of Learning,temperate regions, LLC except that in po- © Jonesrelatively & Bartlettlarge planktonic Learning, copepods LLC and benthic NOT FORlar SALE seas the OR conditions DISTRIBUTION endure much longer. There, NOTconsumers, FOR SALE particularly OR DISTRIBUTION amphipod crustaceans and Seasonal Patterns of Marine Primary Production 123 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & BartlettComparison Learning, of Arctic LLC and Antarctic Oceanographic© Jones Features & Bartlett Learning, LLC NOT FOR SALE FeatureOR DISTRIBUTION Arctic NOT FOR SALE OR DISTRIBUTIONAntarctic Shelf Broad,two narrow openings Narrow,open to all oceans River input Several None Nutrients in photic zone Seasonally depleted High throughout year Table 4.2 Table Icebergs © Jones & Bartlett Learning,Small,irregular,not LLC in arctic basin ©Abundant,large,tabular Jones & Bartlett Learning, LLC Pack ice NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Maximum area (×106 km2)13 22 Age Mostly multiyear Mostly 1 year Thickness 3.5 m 1.5 m

© JonesAdapted from & Hempel,1991. Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION bivalve mollusks. As the sea ice continues to melt whether terrestrial or marine, depends on marine toward the poles in early summer, the zone of high food webs supported by this massive upwelling. phytoplankton productivity follows, and the stage Comparable latitudes in the Arctic are interrupted © Jones & Bartlettis then set Learning, for short foodLLC chains supporting a very© Jonesby land& Bartlett masses Learning,to form the smallLLC regional Bering, NOT FOR SALEproductive, OR DISTRIBUTION seasonal, migrating ice-edge commu-NOT FORBaffin, SALE Greenland, OR DISTRIBUTION and Norwegian Seas. Some impor- nity of diatoms, krill, birds, seals, fishes, and whales. tant features of the two polar regions are compared Animals that do exploit this production system must in Table 4.2. be prepared to endure long winter months of little primary production.© Jones Common & Bartlettresponses Learning, of homeo- LLC © Jones & Bartlett Learning, LLC therms to cope withNOT the FOR seasonal SALE variability OR DISTRIBUTION in their NOTSUMMARY FOR SALE POINTS OR DISTRIBUTION food supplies include extended fasting periods and long migratory excursions to lower-latitude waters Seasonal Patterns of Marine Primary Production in winter (see Chapter 7). • Spatial and temporal variations in available sun- In addition to these similarities, some strong light, nutrients, and grazers cause significant © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC contrasts exist between north and south polar marine seasonal and global differences in marine pro- environments,NOT FOR SALE and so OR do someDISTRIBUTION of their productivity duction.NOT A FOR diatom SALE bloom ORduring DISTRIBUTION the spring, fol- patterns. The Arctic is a frozen ocean surrounded lowed by the successional appearance of by continents; the Antarctic is a frozen continent less-numerous dinoflagellates during the sum- surrounded by ocean. Much of the Arctic Ocean is mer, is the prominent scenario of production in © Jones & Bartlettpermanently Learning, covered LLC by fast ice, and because© so Jones &temperate Bartlett seas.Learning, LLC NOT FOR SALEmuch OR of theDISTRIBUTION year passes in darkness with almostNOT FOR• SALE Tropical OR and DISTRIBUTIONsubtropical waters exist in eter- no phytoplankton growth, the annual average pro- nal stratification, with low rates of production ductivity rate there is low (about 25 g C/m2 per yr). and year-round plankton communities that re- Around the Antarctic continent, however, upwelling semble those of temperate regions during sum- of deep nutrient-rich water supports very high summer months. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC mertime NPP rates and annual average rates of about • Rates of net primary production in areas of 150 g C/m2 per year.NOT In theseFOR regions, SALE water OR DISTRIBUTIONthat sank coastal upwelling areNOT among FOR the highestSALE inOR the DISTRIBUTION in the Northern Hemisphere returns to the surface sea; however, they are very limited in geographic in an uninterrupted zone of upwelling that extends extent, and some of the most important ones around the entire continent to support a band of are interrupted by El Niño events. high© Jones phytoplankton & Bartlett productivity Learning, from LLC the ice edge • The© seasonal Jones formation& Bartlett and Learning, melting of sea LLC ice northNOT toFOR the AntarcticSALE OR Convergence DISTRIBUTION between 60° S andNOT tremendous FOR SALEvariations OR in availabilityDISTRIBUTION of sun- and 70° S latitude (see Fig. 3.40), bringing with it a light greatly influences production in polar seas, thousand-year accumulation of dissolved nutrients. yet photosynthesis can continue around the The extraordinary fertility of the Antarctic seas stands clock during a few summer months to create dense populations of phytoplankton. © Jones & Bartlettin sharp Learning,contrast to theLLC barrenness of the adjacent© Jones & Bartlett Learning, LLC NOT FOR SALEcontinent. OR DISTRIBUTION Consequently, almost all Antarctic life,NOT FOR SALE OR DISTRIBUTION 124 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & BartlettGlobal Learning, Marine LLC © Jonesdaily carbon & Bartlett fixation Learning, within the LLC water column is NOT FOR SALE PrimaryOR DISTRIBUTION Production NOTestimated FOR SALE (by using OR the DISTRIBUTION relationship between tem- 4.5 Obtaining accurate estimates of primary perature and maximum phytoplankton-specific productivity from the ocean on a global scale is no growth rates) or assigned a constant value. Since easy task, even with the help of satellite technology 1994, the Ocean Primary Productivity Working Group, a NASA-sponsored team of oceanographers, as described in Chapter© Jones 3. Perhaps & Bartlett the most Learning, diffi- LLC © Jones & Bartlett Learning, LLC cult aspect of production estimation is the develop- has been comparing the performance of various NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION ment of a model that will transpose satellite-imagery productivity algorithms in an attempt to establish data into reliable estimates of marine productivity. a NASA-resident “consensus model” for routine esti- Proposed algorithms typically attempt to integrate mation of marine production. We view these data- many data sets simultaneously, such as surface wind bases, production models, and “consensus algorithms” stresses,© Jones vertical & profiles Bartlett of 14Learning,C-based carbon LLC fixa- as continuously© Jones evolving & entities Bartlett that Learning, become better LLC tion,NOT precipitation, FOR SALE variable OR fluor DISTRIBUTIONescence data col- refined eachNOT year, andFOR we SALE present OR current DISTRIBUTION best esti- lected using a Fast-Repetition-Rate fluorometer, sea mates of ocean primary productivity in the follow- level pressure, depth-integrated carbon fixation, sea ing paragraphs. surface temperature, relative humidity, wavelength- Mid- and high-latitude regions, shallow coastal © Jones &integrated Bartlett surface Learning, photosynthetically LLC active radiation © Jonesareas, and & Bartlettzones of upwelling Learning, generally LLC support large NOT FOR(or SALE PAR), OR ice cover,DISTRIBUTION surface chlorophyll concentra- NOTpopulations FOR SALE of marine OR DISTRIBUTION primary producers, but most tion, aerosol optical depths, daily photoperiod, depth of this production is accomplished during the warm of the photic zone, and the vertical distribution of summer months when light is not a growth-limiting chlorophyll. As if this is not complicated enough, factor. Open-ocean regions, especially in the tropics model-generated estimates of marine production and subtropics, where a strong thermocline and pyc- using these data sets© are Jones greatly & influenced Bartlett Learning, by as- nocline LLC are permanent features,© Jones and in & polar Bartlett seas, Learning, LLC sumptions and data correctionsNOT FOR made SALE by researchers; OR DISTRIBUTIONwhere light is limited throughNOT much FOR of the SALE year, have OR DISTRIBUTION for example, scientists at Rutgers University have low rates of NPP (55 g C/m2 per year). estimated annual global ocean production to be be- Table 4.3 lists and compares the annual rates of ma- tween 40.6 and 50.4 billion metric tons of carbon rine NPP in several different regions (see Fig. 4.34 for a per year.© Jones The variation & Bartlett in these Learning, estimates LLC is due to visual representation).© Jones Total& Bartlett NPP estimates Learning, included LLC iterationsNOT ofFOR their SALE model OR when DISTRIBUTION surface irradiance in synthesesNOT such asFOR this SALEhave been OR revised DISTRIBUTION upward is corrected for cloudiness or not, when surface nearly 75% with the use of satellite-derived observa- photoinhibition of photosynthesis is assumed to tions. About 76% of the total NPP occurs in the open be present or absent, or when the optimal rate of ocean, spread thinly over 92% of the ocean’s area. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Rates of Net Primary Production for Several Ocean Regions Area Percentage Average Total NPP (Region (؋106 km2) of Ocean (g C/m2/yr) (109 tonnes C/yr Open ocean © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Tropics and subtropics 190 51 55 10.45 Table 4.3 Table Temperate and subpolarNOT FOR SALE OR100 DISTRIBUTION27 206 NOT FOR SALE20.60 OR DISTRIBUTION (including Antarctic upwelling) Polar 52 14 27 1.40 Continental shelf © JonesNonupwelling & Bartlett Learning, LLC26.6 7.2 © Jones &290 Bartlett Learning,7.71 LLC NOTCoastal FOR upwelling SALE OR DISTRIBUTION0.4 0.1 NOT FOR1050 SALE OR DISTRIBUTION0.42 Estuaries and salt marshes 1.8 0.05 975 1.76 Coral reefs 0.1 — 1410 0.14 Seagrass beds 0.02 — 937 0.02 42.50 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALEData from OR Longhurst DISTRIBUTION et al.,1995;Pauly and Christensen,1995;Field et al.,1998;and GreggNOT et al.,2003. FOR SALE OR DISTRIBUTION Global Marine Primary Production 125 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION

The geographic variation of marine primary production,composed from over 3 years of observations by the satellite-borne coastal zone color scanner.Primary production is low (less than 50 g C/m2/yr) in the central gyres (magenta to deep blue),moderate (50–100 g C/m2/yr) in the light blue to green areas,and high 2 (greater than 100 g C/m©/yr) Jones in coastal zones & andBartlett upwelling areasLearning, (yellow,orange,and LLC red). © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION The more productive regions are very limited in ge- turnover rates. About 25% of ice-free land areas ographic extent. Collectively, estuaries, coastal up- supports NPP rates over 500 g C/m2 per year; in the welling regions, and coral reefs produce only about ocean, this value is less than 2%. 2.3© Jonesbillion of & the Bartlett 42.5 billion Learning, tonnes ofLLC carbon pro- The ©entire Jones human & Bartlettpopulation Learning, on Earth currently LLC ducedNOT eachFOR year. SALE OR DISTRIBUTION requiresNOT about FOR 5 billion SALE tonnes OR of DISTRIBUTION food annually to The productivity numbers of Table 4.3 indicate sustain itself, about 12% of the total annual marine that a total of nearly 42.5 billion tonnes of carbon are NPP. Yet for several reasons to be discussed in Chap- synthesized each year in the world ocean, and all but ter 13, this abundant profusion of marine primary 1.92 billion tonnes (95.5%) are from phytoplankton. producers will probably never be used on a scale suf- © Jones & BartlettThat number Learning, is equivalent LLC to a bit more than 90 bil-© Jonesficient & Bartlett to alleviate Learning, the serious LLC nutritional problems NOT FOR SALElion tonnes OR DISTRIBUTION of photosynthetically produced dry bio-NOT FORalready SALE rampant OR in DISTRIBUTION much of our population. Instead, mass, or about 15 tonnes of phytoplankton dry biomass this vast amount of organic material will continue for each person on Earth. to do what it has always done: fuel the metabolic When compared with land-based primary pro- requirements of the consumers occupying higher duction systems,© NPPJones on land& Bartlett is slightly Learning, higher LLCmarine trophic levels. © Jones & Bartlett Learning, LLC × 9 (about 56.4 10 NOTtonnes FOR C/yr), SALE even thoughOR DISTRIBUTION oceans NOT FOR SALE OR DISTRIBUTION cover more than twice as much of the Earth’s surface as does land. The reason for this is that terrestrial areas do not suffer a significant loss of SUMMARY POINTS nutrients as does the photic zone, and thus, land Global Marine Primary Production production© Jones & is Bartlett426 g C/m Learning,2 per year (notLLC including © Jones & Bartlett Learning, LLC permanentlyNOT FOR SALE iced areas). OR DISTRIBUTION In contrast, marine pro- • SpatialNOT variations FOR SALE in primary OR DISTRIBUTION production are duction is 140 g C/m2 per year. Although marine pri- common, with mid- and high-latitude regions, mary producers account for almost half of the total shallow coastal areas, and upwelling zones be- global NPP each year, at any one time phytoplank- ing the most prolific, but only during warm summer months when sufficient sunlight is available. © Jones & Bartlettton represent Learning, only about LLC 0.2% of the standing stock© Jones & Bartlett Learning, LLC NOT FOR SALEof primary OR DISTRIBUTION producers because of their very rapidNOT FOR SALE OR DISTRIBUTION 126 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION. © Jones &STUDY Bartlett GUIDE Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Marine Biology Online 8. Draw a generic graph of diatom concentrations in a temperate sea during the course of a single year, Connect to this book’s Companion Web Site at and then explain the factors that cause the ob- http://biology.jbpub.com/marinelife/10e© Jones & Bartlett .Learning, The LLCserved peaks and valleys ©in Jonesthis annual & Bartlett cycle. Learning, LLC site provides an onlineNOT FORreview SALE area, featuring OR DISTRIBUTION9. What is the El Niño phenomenon,NOT FOR and SALE how does OR DISTRIBUTION chapter outlines, study quizzes, an interactive it interrupt the massive upwelling of the Peru

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r / links to help you explore the b a ice affect primary production in the Arctic and i o m © Jones & Bartlett Learning, LLC/ © Jones & Bartlett Learning, LLC lo g m world of marine biology on y co Antarctic. NOT FOR SALE OR DISTRIBUTION.jbpub. NOT FOR SALE OR DISTRIBUTION your own. 11. Why are tropical waters usually as clear as gin, Any copy of Introduction to the Biology of whereas the temperate ocean often seems as Marine Life, Tenth Edition, that was purchased cloudy as soup? new in North America should include a free, © Jones & Bartlettbound-in Learning, access code LLC for the Companion Web © JonesSuggestions & Bartlett for Further Learning, Reading LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Site. To redeem your code or to purchase access Alongi, D. M. 2002. Present state and future of the separately, please visit http://www.jblearning.com. world’s mangrove forests. Environmental Conser- vation 29:331–349. Blaber, S. J. M. 2007. Mangroves and fishes: issues Topics for Discussion and© JonesReview & Bartlett Learning, LLCof diversity, dependence,© and Jones dogma. & BulletinBartlett of Learning, LLC NOT FOR SALE OR DISTRIBUTIONMarine Science 80:457–472.NOT FOR SALE OR DISTRIBUTION 1. Terrestrial flowers are pollinated by a variety of Bortone, S. A. 1999. Seagrasses: Monitoring, Ecology, insects, birds, and bats. How are the flowers of Physiology, and Management. CRC Press, Boca subtidal seagrasses pollinated? Raton, FL. 2. Why are manatees and dugongs restricted to trop- Bosire, J. O., F. Dahdouh-Quebas, M. Walton, B. I. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ical and subtropical waters even though their pre- Crona, R. R. Lewis III, C. Field, J. G. Kairo, and ferredNOT foodFOR (seagrass) SALE OR occurs DISTRIBUTION commonly at most N. Koedam.NOT 2008. FOR Functionality SALE OR of DISTRIBUTION restored man- latitudes? groves: A review. Aquatic Botany 89:251–259. 3. 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Journal photosynthetic changes, dispersal and survival of the World Mariculture Society 14:345–359. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 128 CHAPTER 4 Marine Plants 1ST REVISE © Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION.