1. Estuaries Semi-enclosed areas where fresh water from rivers mixes with salt water from the ocean

2. Figure 10.22

3. Figure 12.01 Bar built Estuary off Of Cape Hatteras

4. Estuaries Dramatic fluctuations in salinity –Salinity increases with depth –Salinity decreases upstream –Salinity varies with tides

7. Fnft

8. Organisms Must Cope with Salinity Changes Most are euryhaline –Can tolerate a wide range of salinity Or have restricted ranges

10. Organisms Must Cope with Salinity Changes Osmoconformers –Salt concentration varies with salinity Osmoregulators –Maintain constant salt concentration in their bodies

12. estuarine “communities” Open Water Mud (or Salt) Flats Salt Marsh Mangroves

13. Open Water Community Marine plankton comes in and out with tides Many fish use estuaries as nurseries

14. Figure 12.09

16. Mud Flats Where the bottom of estuary becomes exposed at low tide Many infaunal deposit feeders

17. Shoal/Mud Flat

19. Snails, clams, shrimp, & worms

20. Figure 12.12

22. Figure 12.13b

23. What lives In the Bottom? Benthic Community! Infaunal Organisms Sediment Matters! Can be “muddy” (like the mud flat) or “sandy” (like the sand flat)

24. (Bottom) “Intertidal” “Intertidal” zones, between high and low tide, are predominantly related to ROCKY bottoms on the NORTH SHORE (LIS)…but are made of either SAND or MUD (i.e. “soft bottom” habitats) in bays/ponds etc.

25. Figure 11.34

26. Soft Bottom Intertidal Communities Soft=organisms can burrow Sandy beaches, mud flats

27. Soft Bottom Intertidal Communities Unstable, sediments move due to currents, waves and tides Can’t hold on –Not many seaweeds –Animals must burrow = infauna Clams use foot Crustaceans dig Sea cucumbers eat

28. A “foot” in action

29. Figure 11.31a

30. Figure 11.31b

31. Figure 11.31c

32. Figure 11.31d

33. Figure 11.32

34. Soft Bottom Intertidal Communities Grain size of sediment is important

35. Sand = coarse; Clay = fine; BOTH = MUD

36. Fig. 13-23, p.321 Diff. grain size = diff. organismal sizes!

37. What else lives there? SMALL invertebrates Clams Sand Crabs Meiofauna: Tardigrades

38. Donax, fnft

39. Fig. nft

41. “Water Bear” (fnft)

42. Grain Size of sediment indicates water movement –Calm areas = muddy bottoms –Wave and currents = coarser sediment

43. Grain Size of sediment Determines ability to stay wet –Coarse sediments drain fast –Fine sediments drain slower –Mixture – blocks water drainage

44. Figure 11.28a

45. Figure 11.28b

46. Figure 11.28c

47. Problems of living in sediment Dessication is NOT as much of a problem –But it is in coarse sediments

48. Problems of living in sediment Food availability –Most infauna are deposit feeders or suspension feeders –More organic matter (detritus) in fine sediments

49. Problems of living in sediment Oxygen availability –Used up by animals and bacteria –Replenished by water flowing though sediment –Problem in muddy bottoms

50. Problems of living in sediment Oxygen availability –Anoxic = no oxygen –Animals may pump water from the sediment surface or adapt to low oxygen

51. Figure 11.27 Anoxic Mud Line (thus Anaerobic Bacteria Are replacing It w/ Hydrogen Sulfide

52. What if?? That “mud/sand” mixture has “GRASS” or vegetation growing in it? Then it gets a different name – a “Salt Marsh” (like Flax Pond)

53. Salt Marshes Common in temperate regions Extend landward from the mudflats

54. Salt Marshes Dominated by salt tolerant land grasses –Spartina = cord grass (alterniflora and patens) and other grasses (spike grass, switch grass etc.) –Bushes/Shrubs = Groundsel bush, Iva –Some invasives too…

55. Figure 12.14

56. Salt Marsh - HT

57. LOW TIDE!

59. Figure 12.07

60. Pickleweed - Salicornia

63. Local… Now a few slides of your “local” salt marsh, mud flat community and the species that live there…

64. Looking from “wetland” to “upland”

65. Transition Zone: Upland to Wetland (with Phragmites and Baccharis)

66. Spartina alterniflora: Intertidal Marsh

67. <-- Iva frutescens (Marsh Elder) <-- Distichlis spicata (Spike Grass) (low vigor) S. alterniflora (IM)

68. <-- Baccharis halimifolia “Groundsel Bush”

69. “A Salt Panne” w. IM fringe

70. Figure 12.08

71. High Marsh to Low Marsh to Shoal/Mud Flat Littoral Zone

72. Intertidal Mussel Bank

73. Geukensia (Modiolus) demissa: Atlantic Ribbed Mussel

74. High Marsh Low Marsh Shoal/Mud Flat

75. Great Egret Casmerodius albus

76. Egret in marsh

77. Egret Roost

78. Tropical Version We live in the NE, colder climate, so we have salt marshes… In the South, warmer climates prevail, and they get MANGROVES growing in the same “intertidal zone.”

79. Mangrove Forests Common in tropical regions Provide a home to many other marine animals

80. Puerto Rico - Mangroves

82. Figure 12.19

83. Figure 12.21

87. “BRIEF WRAP UP” Food “web” and locations Salt Marsh Open Water Mangrove

88. Locations of these 3 communities