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Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937 (1937)

Chapter: An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch

« Previous: Paleoecology of the Foraminifera - J. A. Cushman
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
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Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
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Page 12
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 13
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 14
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 15
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 16
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 17
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 18
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 19
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 20
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 21
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 22
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 23
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 24
Suggested Citation:"An Ecological Cross-Section of the Lower Part of Florida Based Largely upon its Molluscan Fauna - Paul Bartsch." National Research Council. 1937. Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937. Washington, DC: The National Academies Press. doi: 10.17226/18657.
×
Page 25

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- n - -••;.. *«rjr :'AN, ECOLOGICAL .CROSS-SECTION OF THE LOUER PART OF FLORIDA ..; ,. 'B.ASED .LARGELY UPON ITS MOUUSCAN FAUNA Paul Barsch* :. ' •'•' ••• -• •. •i• . . ' . , ••.•.-• . ,. . . PajLeoecology, probably more than any other phase of earth his- tory-^r. ^hall. I aay science-»-ife an intriguing subject. It is not only that but fascinating, since it off era a challenge to all minds whether these be simple, complex or profound. 'Here each searcher can find a subjectjt-hat vd.ll-expand and keep pace with the growth^, width and breadth of-his paleobiological knowledge, For-this reason there is probably no field of human endeavor, unless it be theisms, in which - more thobbirig^is indulged in than in Paleoecology, •:•*.' The factors that govern the distribution of existing lif& ais not completely known, We have only the 'broader phases within'-our grasp? The infinite details which .determine the to be or not to be of this or that 'vary frequently even.with the extremes in the distributional range of a single species and often very widely so when one considers the-mem- bers of. a single genus, . '-'i-f'.'.* • "„' I have always felt that paleontologists, before entering this specialized branch of science, should have a thorough basic training in Botany and Zoology, and in the latter field stress not the histo-physio- logical phase, but the field studie.s, Ecology, the adjustment of organ- isms to their fellow creatures as well'as, physical environment,, •• . It would be interesting to know how many of America's paleontolo- '•'•' gists would qualify under the above requiremtns/ which to me appear as an absolutely necessary prerequisite, to Paleoecology. :; -i.•:.-••, To one so versed, a tray of Tertiary fossils, fresh from the field, .unassorted, brings to mind visions of habitats where similar associations hold forth today, and his mind's eye quickly pictures conditions paral- leling those in which he found the living forms. His'assumption :of a definite range of depth, temperature, salinity, bottom characteristics, turbidity,: light, current or wave action, and food supply, will probably be almost:correct, certainly more so than it would be if this yardstick had-not 'been applied,...., ''•''{• *• In sections of certain silt deposits of bygone lakes, it has been possible to pin out the annual incx-uiaonttj as definitely and easily as the counting of tree rings. This, unfortunately, is never the case in shallow seas free from river freight of silt and teeming with life-. Here there is a constant intermingling of the living with the dead; the quick seek- * Published with permission of the Secretary of the Smithsonian Institution. 1» Proving preconceived notions.

- 12 - ing shelter among the bones of things gone by mix todays with yester- days to an extent that forces us to abandon days, years, decades and centuries and employ geologic reckoning, Recent, Pleistocene with the Glacial and Interglacial signposts—and these as ill defined as the symptoms of most maladies. I am hoping that when the Everglades National Park will have become a reality, which is soon to be, that some arrangement will be made for a summer course, parallel t6 the Woods Hole seasons, when qualified students under qualified guidance may have an bpporturiity to become acquainted with living marine organisms in their native habitat, and see the many wonderful peculiar, synchronous associations which this region affords. Such an ecologic study on the part of Paleontologists translated into their fossil assemblages, should, I believe, reduce many things assigned different vertical distributional positions on account of the diversity in faunal assemblages to a horizontal field, in which space rather than time constitutes the dominant factor. Once again let me present a cross section of this region, let us say from the center of the Everglades eastward to the Florida Strait. In presenting this picture I shall people my field largely with the creatures that have been my favorite subject for study, the Mollusks; they still play a dominant role in paleontology. Everglades The glades, immense stretches of shallow water with good stands of saw grass that makes wading from point to point a somewhat painful, or at all events, a not altogether delightful enterprise. The uninitiated can picture it by conceiving a partially submerged, luscious meadow, miles upon miles in extent, played upon by the varying breezes and the lights and shades produced by the passing clouds. Here in season we may see in places, Sandhill Cranes, a dozen spe- cies of Herons, Ibises in flocks, the Limpkin, and tilting overhead, or combing the field, Turkey Buzzards, and in spots even now, Everglade and Swallow-tailed Kites. -•- ' . : Paleontologically considered, the glades proper with their feet of muck composed of vegetable detritus and such animal remains as can be preserved in such places, should prove of interest to the Paleontologist. Here we find a peculiar molluscan assemblage: ..' i' •••••'' '* Stagnicola cubensis (Pfr.) , . Heligoma trivolvis intertextum (Sby,) . , , .;• Helisoma scalare (Jay) Helisoma duryi seminole Pils.

-•33- Helisoma duryi intercalare (Pils.) HeLisoma duryi preglabra'tum -(Marshall) Helisoma duryi eudi sous (Pils.)- lV-;' Menetus dilatatus (Gld.) Gyraulus parvus (Say) Physella heterostropha peninsulas (Pils,,) Ferrissia peninsulae (Pils.) v.^.Husoulium parbumeium (Say) :>i:i:'- .•' Eupera cubensis {Prime) •'•'' '•"••-' Leads and Channele in the Everfiplades- •• -''•'• _•-.;.. " v. ~~ " "" • . . . . , Should one fly over the region he would see 'an endless number of slender liquid threads, usually combining into larger leads, which eventually form channels of canoeable size, but the land is so flat that often as not they are mere slender openings in the shallow fields without current or flow. -';Whe?e'itidal"influence Is felt, as well as in .the more elevated reaches 'of- 7theairea, we do have pulsating or more or •'less steadily flowing streams. The edges of "these are particularly fav- 1 orable habitats of the Apple Snail, Pomac ea - depr e ssa , the sole food of the Everglades Kite and to a great extent that of the Ljjnpkin. Here, too, -we find fish of many kinds and sizes, Ttfhieh will at least contribute their scales, and bones, where these are not destroyed in the acid peat, to future paleontologic records . I': . Peopling these deeper reaches we may find the following fresh- water mollusks: ' -'»••« •• •'•• ' - >JM* *•*•- ' ,'-.'±:." .:.:•.-. Pomaeeai <lepressa '(Say) - •' :•' ::-'Ji ;;-'i: -• Stagnicola cubensis (Pfr.) .iT'yc'; .-• ...V. :'+. -L. Helisoma trivolvis intertextum (Sby.) Helisoma scalare (Jay) ...... ..-.-:'... iA_i.-i?. " ^:. '.': '•'.;.- Helisoaa duryi seminole Pils. •..;'o ."..•.:•: , HeliaciMi .duryi intercalare (Pi J.s0) • . •• •> - f; '..'•- Uniomerus obesus paludicolus (Old^) •- •.•'.'•'• Micromya papyraceus (Gould) • '-'••' -^^ '••••' Cyrenella floridana (Dall) Lakes in the Everglades Here and th*re in these large strstches' of submerged meadows we find open bodies-of water, lakes *>f shallow depth where the same mollus- can association'-listed for'the channels holds forth, but here also the Mafcate'e still maintains its precarious e,j&s;&eripex.aj«i so do Alligators.

-14 - Cat-tail Association In places great stretches of these plants (Typha angustifolia) form almost pure dense stands, harboring an associated avian and batra- chian fauna, v. Cypress Swamps Bordering the glades we may have immense stands of Bald Cypress. These are also wading in the shallow waters with their breathing knees lifted above the surface, shedding pollen, leaf and cone year by year, to form a field for the Paleobotanist. Nor is this all, for here the Crocodilians, the Turtles and Snakes, as well as a host of Batrachians, find a suitable home in which they may enjoy life, little disturbed even by man. Bear, Panthers and Raccoons aplenty, as well as many birds, make this their home, and in passing add their bones to the geologic contri- butions of today, .. V. * .' . 4- • Flying over lower Florida brings plainly into view, how the land graudally slopes southward, how barring the hurricane rampart at the southern edge of the mainland, we see to the northward a continuation of the keys that characterize the "Bay of Florida," but gradually lift- ing above the water. Once clear of water we cease to call them keys; they now become "hammocks," which, botanically considered, must be sepa- rated into several associations. ' : , " . ' "l , Palmetto Association This consists of dense stands of Palmettos with small shrubs and grasses as a ground cover. Here some forms of Liguus and Chondropoma dent at urn may be found. Palmetto-Deciduous Association In this the deciduous trees usually predominate, with only a sprink- ling of the former. This will contain the mollusks common to the Decidu- ous Tree Association. The Deciduous Tree Association This frequently forms dense tangles interlaced with vines and - shrubs to form almost impenetrable thickets. The branches of the trees are frequently covered with mats of Orchids, Bromeliads, or Ferns. Here on the trunks of the tall trees we may find some of the members of the 17 named forms of Liguus fasciatus. or of the 9 subspecies of Liguus crenatus, as well as Oxystyla undata (Bruguiere) or Oxystyla floridensis Pilsbry, or Drymaeus multilineaus (Say), Drymaeus dormani (W.G.B.) or Drymaeus domini- cus (Rue.lTWhile occupying a less elevated position, we may see Cepolis

•;*"• • varians (Menke), Cnoridrorioma dentatum (Say) or Hejlicina orbiculata clappi Pils ... and still lower in the shrubbery Bothriopupa variolosa (GldT) and PJJgigoma dioscoricc'la (Ads»), while on the ground, tucked away among the rocky nooks and crannies, or when-showers have moistened the ground, crawling over the vegetable detritus we may find a whole mollusoan faunula as the following list will proclaim; Chondroppma dentatum (Say) ,."..''. .••.'..' .' Helicina orbiculata- clappi Pils, : '• '''• ..' Polygyra uvulifara (Shuttl.) v"-s: .. ; Pra^icqllela jejuna (Say) •''i ^ Lobosciyium pustula (Fer.) •:.'... -..., * :'., . Thysanophora plagioptycha granOm (Streb.) ' •'• • . .' Thysanophora - selenina (Gld.'X-—- ' 1«L. .. Opeas octonoides (Ad,) '- • ' Opeas gracl.ni ma (Pf r. ) Euglandina rosea minor .Pils* .• ...j.^;./ .,, ., .. v ., Holpspira poeyana (Orb.) ...... ".'',.,...'.';. H6i6spii*a jejuna (Gld.) •:..-"•-.. ' ., ...'..' Hacroceramus pontificus -(Gldo)• ''•''•• • Macroceraimis floridanus Pils- . -" • ' . . ... . .',. , .Gastt'bcopta contracta peninsularis'Pdls.' Gastrocopta pent odor-. (Say) :; •: '*'• Gastrocopta rupico3.a (Say) !'••*• • 'Gastrocopta pellucida hordeacella (Pil.s,) Pupoides modicus (Gld.) Sterki.a yhoadsi (Pils.) ;. '.v;^i.. :•' .;-.. ->.-.--i .. P. • Strobilops hubbardi (Brovm) .- ,, . Retinella dalliana (Simpson) ", . .. Retinella indentata paucilirata: (Morelet) ..."-.• .. Euconulus chersinus (Say) • *-r .... . ; Guppya gundlachi (Pfr,).; •'- Guppya miamiensis (Pils.) Hawa3.ia miraiscula alachuana (Dall) i •'. • Zonitoides arbdi'eus {Say) ... ... .. .'"'••••'.*.' Vaginulus flori.danus (Binn.) Carychium exiguum (Say) ;,. -,'.„,]-.. Prairies ," /..'/.";' "''.," '' ' ••' These .^ri^ tne'low-flat dry treeless reaches covered by short grass, .'. ..'U the favorite haunts 6'f th«3 meadow lark, where at times we may find the ground fairly swarming withs •''•''"•' '•' •' ••:• ' Succinea floridana Pils. Polygyra septemvolva volvoxis (Pfr,) Polygyra cereolus (Mtihlf,) PoJygyra carpenteriana (B1d,)

-16 - Pines To the east we find some of the wavelike north and south ridges covered with a stand of scattered pines, or pines and mixed deciduous trees and shrubs, and grass, but with pine dominance. This is poor pick- ing ground for the mollusk. student, for pines proclaim acid soil, which is not conducive to shell life. Here Cerion incannm Binney may frequent the open spaces. Mangrove Flats . ., To the southeast, the Everglades pass by imperceptible stages into the mangrove flats; here low bushes of scraggly mangroves try in vain to gain a foothold. Bayward they gradually grow more luxuriant and form large clumps, lifting their main trunks above the water by their outreach- ing roots or root stems that anchor them in the ground below the water. Here Littorina angulifera and Ostrea floridensis enjoy an airing with each ebbing tide, or the former may prefer the air for a longer period. The Mainland Hurricane Rampart At the southern end of the peninsula, stretching westward from Flamingo City through East, Middle and West Cape Sable, we have a huge sand dune varying in width from a dozen yards to the length of a city block. This represents the wave combings from the shallow floor of the Bay of Florida piled high and dry by Hurricanes and other winds. It con- sists of ground-mp bits of the Bay's life, embodying the skeletons of about everything that has withstood the wave-grinding process. Lagoons and Swales behind the Hurricane Rampart On the landward side of the hurricane rampart we are sure to find a depressed area filled with brackish water, usually in communication by narrow channels with the Bay. Places like these are usually bordered by trees or shrubs, in which Oxy_stvla and Ljguus hold forth, and in the but- ton bushes at the water's edge, Florida Red-winged Blackbirds and Boat- tailed Grackles makes their nests, while among the decaying leaves in the pools Hamlnoea elegans Gray finds a favorable home, Salt Pans In the northern edge of the Bay of Florida are some keys struggling hard to rise from the sea, or more probably to return to it at present. These frequently are barren rings with a slight central depression. These pans are sufficiently submerged at each high tide to admit a new influx of salt water through narrow channels to the shallow basin. Warm breezes and the sun's rays evaporate a great part of the water during the emergence

- 17 - of the rim with the result that the contents of these pans Become hyper- saline, and not infrequently deposit layers of salt. In such salt pans we find a curious faunal assembly of Brine-^Shrimps. anif. •>.:..i;'•' .•'. . • ;. . (^. Cerithidea scalariformis Say • "-':'.- .. . Cerithium minjjnum Gmel. • a • : ,j.4 Anomalocardia cuneimeris Conr. Cyrenella flbridaria Dall Mulinia lateralis Say Pteria atlantica Lam. Mytilus exustus L. Tellina Black Mangrove Association ....... :.__..: "•'•' •'• '. '"'• '•' •':•.•• • • . r '.-'•: ..: K- . Bordering the southern end of Biscayne Bay> on the mainland, we :..:..:'..havejquite a stand of B^ack Mangrove trees", south of, and here and there among these, stretches of fine sharp sand mixed with vegetable detritus and the combing of the waves; here under old decaying logs :or boards when these are turned over, we are sure to find caches of thousands of speci- mens of the beautiful, small, Truncatolla caribaeus Rve, and T^imcateLLa •jV pilabiatus Pfr, and Melampus fjoridanus Shuttl. and ^fela^u^ j^eatus Say. Next we must consider the Bays, for lying off the mainland we have a series of shallow expanses of water kriown as Biscayne Bay, Barnes Sound^ Card Sound and Little Card Sound, which occupy the trough between-the mainland and the string of keys offshore. Later we shall speak of a second trough between these keys and the edge of the outlying reef known as Hawk Channel. ,;. Brackish Water. Channels In the bays and sounds we have numerous flats and shoals> some laid . bare at low tide,, cJLeft by harrow or wider channels to give access to the 'i -"ipulsating sea. ..".' '..* - --..... - '..:•• ; ..••; *.'v- • Where these channels communicate wi.th the rivers suoh> for example, as Miami-River, we. get mingling of salt and fresh water, produc-ing a brackish condition where Cerithidea gcalarif_qrmis Say and Cerithidea iostoma Pfr, are at. home with Cyrenella florj.dana Dall and Congeria leucophaeata Oonr. Pilings and Docks. ... On. the JJiiteS in the harbor region and the stakes throughout the bays where these have not "been protected by heavy creosoting, we may find a heavy incrusting with Barnacles," Ascidians, Bryozoa and. Modiolus demissus_ (Dillwyn) and Pinctada radiata (Leach),, while the wood where not protected

- 18 - or sufficiently protected, may be riddled with Teredo floridana Bartsch and Bankia gouldi Barsch, or chewed away by Sphaeroma destructor Deep Channels Leading to Sea These now are dredged places as straight as ,the configuration of the bay will permit, but in the days gone- by they were not laid out by rule and compass, but sinuous natural passages winging their way to sea through low flats, usually steep-sided. Here Oysters and Pholads found a desirable habitat. * Ostrea virginica Gmelin Barnea costata Linnaeus Halimeda Association Some of the shallow water flats are covered by an almost pure stand of the calcareous alga Halimeda. which crunches under foot as one walks across, The segments of this form dense patches of considerable thickness. •'. • • . *- ' •''-•' • .*••,'•* Porites Association Under conditions apparently the same as those under which Halimeda occurs, frequently only separated by a lead of a few feet in width from this, other flats are characterized by a dominance of Porites furcata, the small branched coral easily held in the palm of a hand. \. . i <:' • KEYS * *',*•'• > • : "' I The 1-Iangrove Fringe of the Keys on the Bay Side, under water Cn the bay side of the keys we usually have a moderately deep channel fringed by mangroves whose sprawling, outreaching roots repel all approach to the key from this side. Cn these roots below low tide we find clusters of Melina alata (Gmel.), while a little higher in the inter-tidal reaches Ostrea floridensis Sby. forms dense masses that com- pletely cover the roots and at low tide, when out of water, furnish plain proof the oysters here grow on trees. Here, too, we can find specimens of the beautiful Cowry, Cypraea exanthema L., under water. The Mangrove Fringe of the Keys. out of water Cn the mangrove roots, sometimes a yard or more above high tide level, Littorina angulifera Lam. is found abundantly, while on the beach among the drifted flotsam and jetsam Melampus coffeur (L.) and Auricula peHueens Mke. may be found in abundance, and Strobilops hubbardi steven- soni Pils. occurs under the bark of dead limbs.

-19 - Interior of Keys Here where avaricious man has not destroyed the native forests we still find heavy stands of Gumbo limbo, Mahogany, Poison Tree, Wild Tama- rind, West Indian Birch, Darling and Coco plums and many others freighted with epiphetic orchids, Ferns and Bromeliads. On their boles and branches a sprinkling of Liguus can be found, and not infrequently their center harbors a little prairie with an abundance of Cerion incanum Binney, and Succineas. Cuts. Ripraps The harbor improvements of Miami have wrought many changes in Biscayne Bay; mud flats have been changed into islands by pumping the dredged material upon them, and in many places where Halimeda or Porites .reefs held forth we now find luxurious homes surrounded by or buried in . a mass of floral glory. Here the landscape architect has had an opportu- .-;;.. nity and he has used it in bringing here things beautiful from everywhere. The shallow cuts which in days of old made you wait for a high tide to slip across the bar, even in a moderate-draft boat, have been widened and deepened to admit shipping of all kinds, and that these chan- nels may not be filled by the ever southward shifting sharp sands of the outer beaches, long ripraps with stone facing have been placed on the north side of the cuts to shunt the sands eastward into deep waters. These jetties or sea walls are not only favorite places for the disciples of Izaak Walton, but have made a paradise for certain mollusks, which in the past found it difficult to locate a suitable place of at- tachment. Here we now find abundantly: • i Tectarius muricatus (L0) Ceratozona rugosa (Sby. ) Siphonaria lineolata (d'Orb.) NerLta peloranta L. Nerita versicolor Gmelin Thais floridana (Gonr.) Fissurella alternata Say The Sea Side of the Keys This presents another hurricane rampart where wind and waves, combing Hawk Channel, pile the product of their'labors high and dry. This may present long stretches of loose, more or less shifting sand, . - where Cenchrus t ribuloides , the devilish sandspur, makes walking a misery, ';.-. or equal reaches of loose sand held down by the long runners of the Goats- foot Morning Glory, Ipomaea pes-caprae and Ipomaea bona~nox (Lx.). Still

- 20 - other places where the long stolons ..of-the gracefully swaying Bermuda Grass are more or less successful-in checking the wind-blown sand. On the. inner edges the funereal- -Tournefortia holds sways and forming the outer edge 'of the'-woods,-the sea grape with its leathery, shining, kid- ney-shaped leavs&.and.pe&dant racemes of fruit, makes a characteristic - setting enjoyed by Cerion incanum Binney. . ' .:.ul.- ..;•• _ ,,/_.. Shallow-water Sandy Stretches beyond the Keys When these are-'present they enable the burrowing mollusks to dig in, while the predatory members! of, the phylum hunt them out and devour them. Where the wind-swept waves,, roll up on such beaches we frequently .see myriads of the'-lively Coquina slams swept on the beach by each /on- coming wave, .right themselves, and .dig in before the wave recedes. While small, they are so abundant that they-/furnish an element of commerce. To the knowing one, Coquina broth brings pleasant memories to the palate. Their abundance in'the region in -the,- past is vouchsafed by Coquina Rock, • of which Donax contributes the chief element. . Here also we will finds » ., '•'• 'DonaSc vfcriabilis ,Say . •':7' •'OiiVella floralia JXio.1.08 .- .* ."' :--•-i-- Olivella Mutica .Say-s:, .,.'.' Marginella apicina Menke • : Terebra dislocata Say «• Terebra protexta Conrad .,-" MLtrella lunata (Say) Epitonium angulatum (Say); . '. . Laevicardium mortoni (Conrad) Polinices duplicata (Say)....,. . Tellina altemata Say ,..('. Dosinia discus Reeve Busycon perversa (L.) ^ . Alectrion vibex (Say) ;'- • ''— • .. . ^. Strigilla flexuosa Say ... ghallow water (Hard iaan) beyond, the Keys ' ,'.'. ' t •"•• :• ,. • ••• "... . , ..: . r . Off the keys "oh the sea side we have streaks-of. hard, pan where Corallines, Foramirii'f era .and Algae encrust the bottom. Here Chama sarda Reeve and Glycimeris americana Defrarice'arid the following find a suitable habitat: Anachis avara (Say) Cantharus tincta (Conr.) Leucozonia cingulifera (Lam.)

- 21 - i • * * , ** Clathrodrilla ostrearum (Stearns). .." Thais haemastoma (L. )•''' . , ftLssiiraUa alternata (Say) Phos parvus Co 3. Ad, . •• .:> ; '. Tritonalia celluibsa Conrad -:...-. ••: . ischnochitonrlimaclfbrmis. Sby. • - :••. Biirex pomum (fcnelin ' ' ..'.'... '-'• ' '•- •". . •'• '.. •:':.'•.-•:. : Shallow waters (Mad flats) beyord tha Keys ... . • *""""' ** ~ - • '• ...... Here and there in Hawk Channel we find mud flats In shallow water where among other creatures the following mollusks are at homes Acteocina'canaliculatus (Say) .. : Mangelia cerina K. & S. Epitonium lineatum (Say) • ' ... Cerithium ferruginexun Say : ••• '*'*• Cerithium muscarum Say ' Tageius gibbus (Spengler) Cardita floridana Conrad Pyramidella crenulata Holmes . . • Coral Reef Walls Offshore, beyond Hawk Channel, which stretches outside of the keys from Miami south to Key West, is another submerged ridge, which at inter- vals bears a series of lighthouses. This ridge supports a thriving coral reef, which extends even farther south past the Marquesas and the Tortugas. Here we find walls of corals exposed to the surf, with leads between them, or at times just coral patches. These massive builders, embracing Orbji^^lla. amula^ris (Dana), Porites astrerides Lamai-ok, Sidgragtrila sjiderea., JfeandrT.a strigosa (Dana) and~Hjan?ra labyrinthif orrnis ^L-'jnnaeu.jj produce veritable, walls of coral limestone, which contain an endless number of grottoes, caves and caverns in and among which dozens of species of fish seek shelter, fish ranging from the huge Sea Bass wa.ighi.ng at times several hundred pounds to the tiny exquisite Iridio. Here brj-lliant leisurely Angel and Butterfly Fishes search for food, while schools of hundreds of Gray Snappers stay put and sway all day long under sheltering ledges, in the pulsating surge., waiting for the close of day :to .begin their foraging „• Schools of hundreds of Yellow Tails and. Caranglds will 'pass in review as they cover their beat, while the Banded Schoolmasters play about the summit of the blocks, enjoy- ing the varying lights anii shadows occasioned by the wave lens, surface of the sea, or swift ind dangerous Bara^uda move leisurely about*. singly op in pairs, To here list the whole' fish ass^ioblage would take more space than is allotted to me^ and to adequately record the scene requires not

- 22 - pen or pencil or even brush, but a diving helmet and water-tight moving picture camera, using color film to do justice to the view. Tucked away here among the nooks and crannies, we find all the nestling and burrowing mollusks. Gorgeous Lima scabra Born tucked away in small crevices displays its bright tentacles, while sombre Chama congregata Conrad and Vermetus nigricans Dall are fixed to the solid rock. Sandy Stretches between the Coral Walls • ., * i*' ...*•"..' ** • -,', -. .•. . c • • Between the solid walls of coral are flat stretches of white sandf comminuted bits of coral and shell with small lumps of detached corals usually furnishing attachment for the purple and yellow fan coral and various other species of Gorgonians. Here the Hog fish and various species of garishly colored Parrot Fish and Slippery Dicks and the burrowing Gnathops and the Stingaree and sometimes Manta birostris find a suitable habitat, and the long-spined Black Sea Urchin, Centrechinus antillarum Phil., whose contact one should avoid, nay live singly or in bunches of several dozens. At home here also are: Dosinia elegans Conrad Anodontia alba Link Oliva sayana Ravenel Polinices duplicata Say Natica canrena L. Sinum perspectivum Say Tonna galea L. Stag-Horn Coral Association : . Even among corals we have associations, as exemplified.by the stag- horn coral, Acropora cervieomis, which in places forms dense stands.cover- ing considerable space. To a somewhat lesser extent this is also true of the Palmate Coral. Acropora palmata. i • Gorgonian Field •i •• j. . •• • • . . • In the flats inside of the other reef we find extensive fields of Gorgonians, forming the so-called "Sea Gardens," composed chiefly of va- rious species of Plexaura, Xiphigorgia. Gorgonia, Muricea. Eunicea and Pterogorgia. Museum specimens give little idea of the real beauty of these so-called "Sea Garden" denizens where the half-inch investment of slender zooids that characterizes them in life is shrunken into a thin animal film. Wading among them with a diving helmet, or viewing them through a water glass from above, certainly justifies the novices' name "Sea Garden" for they sway and bend to currents, the surge of waves or the pulsation of the sea as do plants on shore which their forms resemble.

.•-- 23 - These colonial animals contribute largely to the reef deposits by adding their spicules upon their demise. Among them, on the sea fans our molluscan friends, Simmia uniplicata (Sowerby) and Cyphoma gibbosa. (L.), find their favorite habitat. Grassy Patches ——••—•— • • g • • (-• Betwixt the Coral walls and the Gorgonian fields we may have long stretches of grass covered sand bottom, composed of the Sea Grass, Thalassiaj among which the trunklike Cowfish, Pipe Fishes, and the Sea Horses dwell* This, too, is the favorite habitat of the red Giant Star Fish, Oreaster reticulata L., and Tripneustes esculentus Lo, and the Giant Horse Conoh, FascjiQlaria gigantea Kiener, the largest Gastropod of the Atlantic, and Fasciolaria tulipa L., as well as the King and Queen Conchs, Caggig madagascarensis Lam., Cassis tuberosa L., and above all the Pink Conch, Strombus gigas L., whose delicious flesh has gained the name "Conch" for those devoted to this fish. Mixed in with these are Holothurians, while among the lesser folk may be listed the soft Sea Hare, Aplysia willcoxl Heilprin, Conus pealii Green and Nassarius ambiguus Monts. The Continental Shelf. 5-100 fms. Passing the reef area we come to a gradually sloping submarine plain of varying width, the so*-called Continental Shelf, which we may say ranges down to 100 fathoms0 This is a rich molluscan field; here among many others the following'species hold forth? Tellina lintea Conrad Acteon punctostriatus C9 B. Ad. Drillia ebur Reeve Maculopeplum junonia Hwass^ Xenophora conchyliophora Born PMinices uberina d'Orb-." Epitonum hellenica Forbes Eulima carolii Da3JL Niso interrupta Sby. •.s ... . Pyramidella cai;di.da MOrch. Calliostpma euglypbum An Ad. >T Calliostoma ju.jubinum Gmel, ' .,.,'..•-,• Cadulus quadridentatus Dall Pourtales Plateau, 90-300 fathoms By far the? richest niarine molliisk field is the Pourtales Plateau to the east of the Continental Shelf, whose varied bottom ttiems with all sorts of life. .;

- 24 - '*-'•'• As a modest,representative selection of the fauna we. may mention: Area glomerula Dall '.; •'•" Euciroa elegantissima Dall Acteon exilis Jeffreys Protocardia peramabilis Dall •'Modibla Polita Verrill & Staith Leucosyrinx verrillii Dall Leucasyrinx subgrandifera Dall '... •• '"•> Ancistrosyrinx elegans Dall • i '•: ,..: .• Ancistrosyrinx radiata Dall • -1 Genota. viabrunnea Dall" . .. i - Mangilia cerina Dall • • • Mangilia comatotropis Dall "••'•'' --•' Marginella succinea Conrad ... '.' .!,:.•;:.' . \Aurinia dubia Brod. ... j-v:/:v- Aurinia gouldiana Dall , Fusinus- benthalis Dall ,. v . '.; Phos candei d*0rb.~ Murex beaui Fisch. & Bern. Coralliophila deburghiae Rve. -v ••••'..' Padicularia decussata Gould .. t'is' Omalaxis nobilis Verrill ..' • Amalthea benthophila na1l Xenophora conchyliophora Born Pyramidella Candida Mbrch Microgaza rotella Dall . -.-., Calliostoma bairdii Dall •','•.,.,' . Solariella ottoi Phil. . ,-:' * Liotia bairdii Dall Haliotis pcurtalesii Dall ... ; Dentalium antillarum d'Orb. . Dentalium laqueatum Verrill Bed of Florida Straits Still further east-than the Pourtales Plateau come the Florida Straits, ranging from 350 to 800 fathoms in depth„• from which we may list: Glyphostoma gratula Dall Mangilia serga Dall: '•.'-.'< .•-.-..--, Pleurotomella chariessa Dall '; '•;'. Fusinus benthalis Dall ... Leptothyra induta albida Dall Margarita (Bathymophila) euspira Dall Solariella ottoi Phil. Dentalium perlongum Dall Dentalium callithrix Dall Daphnella lunacina Dall

Plankton This presents still another phase of life that we have so far com- pletely ignored, but which is of immense importance to the marine animal world, The Phytoplankton, the microscopic free-swimming plants have been aptly called the grazing grounds of the sea, The large protozoan admix- ture, as well as eggs and larval stages of animals, and the pelagic crea- tures that prey upon them found in this liquid habitat, constitute an im- mense element of marine life. Among mollusks, we may mention the Squids, Spirula, the Pteropods and Heteropods; among the shelled Protozoa, Foraminifera on dying, drop enough skeletons to form an ooze known by this name, while others, like the Peridinae, at times are present in such countless numbers as to smother life in the region invested, requiring a restocking of the fauna of the place. This killing off occasionally is also due to the presence of Pseudomonas, likewise a flagellate protozoan .whose contribution of ammonia to the sea causes enough disbalance to pro- duce sufficient chemically precipitated ooze, suspended in the :water and on the bottom also, to choke all life, . :.,:-• •'.':e In this brief account I have purpbsely avoided mentioning the nu- merous minute species of the families Epitoniidae, Melaneliidae, Pyrami— dellidae, Caecidae, Rissoidae, Tripheridae, Cerithiopsidae, Vitrinellidae and others, since these are not the obvious things of the fauna0 I have selected those mollusks which force their attention upon the observer in each habitat; they, therefore, represent'the striking element of each as- sociation. Inclosing, may I express the hope that this brief account will arouse the interest of students of Ecology in this, the most marvelous field for such studies known to me. Uno, National Museum, Washington, D, C•

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Report of the Committee on Paleoecology, 1936-1937; Presented at the Annual Meeting of the Division of Geology and Geography, National Research Council, May 1, 1937 Get This Book
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