freshwater flashcards bruh

1. What is a wetland?

An ecosystem where water is present long enough to create hydrophytic vegetation, hydric soils, and wetland hydrology.

2. What is hydrophytic vegetation?

Plants adapted to saturated, low-oxygen soils.

3. What are hydric soils?

Anaerobic soils with gleyed colors, redox mottles, and high organic content formed under saturation.

4. What is wetland hydrology?

Indicators of water presence such as saturation, water marks, standing water, and sediment deposits.

5. What are the three wetland delineation characteristics?

Hydrophytic vegetation, hydric soils, and wetland hydrology.

6. Define emergent macrophytes

Plants rooted underwater with stems/leaves above the water surface.

7. Define floating macrophytes

Plants that float on the water surface; can be rooted (water lilies) or free-floating (duckweed).

8. Define submerged macrophytes

Plants that grow entirely underwater.

9. Define obligate wetland plant (OBL)

Species found in wetlands >99% of the time.

10. Define facultative wetland plants (FAC, FACW, FACU)

Plants occurring in both wetlands and uplands with different wetness preferences.

11. Difference between a marsh and swamp?

Marsh = herbaceous vegetation; Swamp = woody vegetation.

12. Difference between seasonal and permanent wetlands?

Seasonal = water part of year; permanent = water all year.

13. Difference between freshwater and marine wetlands?

Freshwater = no salt influence; marine = tidal and saline influence.

14. How are macrophytes arranged by depth?

Emergent → floating-leaved → submerged as depth increases.

15. What are lacunae/aerenchyma?

Air-filled spaces that transport oxygen to roots in anoxic soils.

16. What are buttresses?

Widened tree bases for stability in soft soils.

17. What are pneumatophores?

Upward-growing “knees” that allow gas exchange above water.

18. What are adventitious roots?

Roots growing above anoxic layers to access oxygen.

19. What is the boundary layer?

Thin layer of slow-moving water around submerged surfaces where diffusion is limited.

20. How does velocity affect boundary layer thickness?

Low velocity → thick boundary layer; high velocity → thin boundary layer.

21. How do dissected leaves help with diffusion?

Reduce boundary layer thickness and increase CO₂ uptake.

22. Why are wetland plants slow-growing?

They invest energy into structural adaptations and grow in poor, anoxic soils.

23. What does low nitrogen content mean for wetland food webs?

Plants are poor food; detritus and algae dominate energy flow.

24. Primary food sources in wetlands?

Detritus, epiphytic algae, and bacteria.

25. Benefits of wetlands?

Flood control, water purification, denitrification, sediment trapping, habitat, carbon storage.

26. Major threats to wetlands?

Draining, filling, agriculture, invasive species, hydrologic modification, pollution, deforestation.

27. Why do wetland plants outcompete upland plants in saturated soils?

They have adaptations for anaerobic conditions.

28. Why do upland plants outcompete wetland species in dry soil?

Wetland plants allocate energy to non-competitive traits like gas structures.

29. Why are wetland waters often nutrient-poor?

Slow breakdown of organic matter under anoxic conditions.

30. How does hydrology determine wetland type?

Duration, depth, and source of water drive vegetation and soil formation.

31. What is sediment trapping?

Wetland vegetation slows flow, causing particles to settle.

32. How do wetlands remove nitrogen?

Microbial denitrification converting nitrate to N₂.

33. How do wetlands store carbon?

Peat accumulation under anoxic conditions.

34. Why are wetlands biodiversity hotspots?

High habitat complexity and energy inputs.

35. What does facultative upland mean?

A plant usually found in uplands but tolerating occasional wet conditions.

36. Why are littoral zones important?

They support most macrophytes and benthic productivity.

37. What causes zonation in wetlands?

Light, oxygen levels, nutrient availability, and water depth.

38. Why are wetlands vulnerable to drought?

Their hydrology and vegetation depend on saturation regimes.

39. What defines streams hydrologically?

Unidirectional flow driven by gravity.

40. What is discharge?

Volume of water per time = width × depth × velocity.

41. What factors affect discharge?

Rainfall, snowmelt, tributaries, slope, channel shape.

42. What increases downstream?

Discharge, width, depth.

43. What decreases downstream?

Slope, substrate size.

44. What happens to velocity downstream?

Often stays same or increases due to reduced friction.

45. What is the hyporheic zone?

Mixing zone of groundwater and streamwater under/along the streambed.

46. Runoff vs groundwater flow?

Runoff = flashy/turbid; groundwater = steady/cool.

47. What is a hydrograph?

Plot of discharge over time showing storm response.

48. Define pools

Deep, slow-moving sections of a stream.

49. Define riffles

Shallow, fast sections of a stream.

50. What are microhabitats?

Leaf packs, gravel beds, undercut banks.

51. What is stream order?

Classification increasing when two streams of same order join.

52. What is a meander?

Stream bend with erosion on outer bank and deposition on inner bank.

53. Frequency of meanders?

Every 7–10 stream widths.

54. What is load?

Mass transported per time = concentration × discharge.

55. How does rain affect load?

Can dilute concentration but increase total load.

56. Relationship between velocity and substrate size?

Higher velocity moves larger particles.

57. What is CPOM?

Coarse particulate organic matter >1 mm.

58. What is FPOM?

Fine particulate organic matter 0.5 μm–1 mm.

59. What is DOM?

Dissolved organic matter <0.5 μm.

60. What breaks CPOM into FPOM?

Shredders, microbes, and mechanical abrasion.

61. Major stream primary producers?

Periphyton and algae.

62. Organisms in periphyton?

Diatoms, green algae, cyanobacteria, bacteria, fungi.

63. Autochthonous production?

Organic matter produced within the stream.

64. Allochthonous production?

Material entering from land (leaves, soil).

65. What is nutrient spiraling?

Cycling + downstream transport of nutrients.

66. What shortens spiraling length?

High biological uptake and retention.

67. What lengthens spiraling length?

High discharge and impaired biota.

68. Why does long spiraling increase eutrophication risk?

More nutrients exported downstream.

69. Major consumers in streams?

Insects, crustaceans, fish.

70. Shredders eat what?

CPOM.

71. Scrapers eat what?

Periphyton.

72. Collectors eat what?

FPOM.

73. Predators eat what?

Other animals.

74. RCC headwaters

narrow shallow shaded low light allochthonous material dominates for energy input

75. RCC mid

Wider shallower slope autochthonous material dominates more light more production

76. RCC large rivers

turbid reduced light rely on carbon input material from upstream

77. What does RCC fail to explain?

Dams and floodplain processes.

78. Serial Discontinuity Concept?

Dams disrupt natural gradients.

79. Flood Pulse Concept?

Floodplain inundation drives productivity.

80. Flow adaptations?

Flattened bodies, hooks, suction discs, fusiform shapes.

81. What is invertebrate drift?

Downstream movement of organisms.

82. When is drift highest?

At night.

83. How do populations stay upstream?

Adult insect flight, crawling upstream.

84. What causes drift?

Predation, competition, dislodgement, behavioral release.

85. Why are headwaters heterotrophic?

Low light, high leaf input.

86. Why are mid-reaches autotrophic?

Increased light and algal growth.

87. Why are large rivers turbid?

FPOM accumulation and sediment inputs.

88. What are dead zones (in streams)?

Areas behind rocks with low velocity.

89. Why is periphyton important?

Primary energy source and indicator of water quality.

90. How does substrate size affect periphyton?

Larger substrates = more stable habitat.

91. What is a stream reach?

A discrete study section of stream.

92. What is groundwater upwelling?

Groundwater entering stream from below.

93. What is downwelling?

Streamwater entering hyporheic zone.

94. Why does turbidity reduce photosynthesis?

It blocks light.

95. What defines a flashy stream?

Rapid changes in discharge after rainfall.

96. How do sediments threaten ecosystems?

Increase turbidity, carry nutrients, smother habitat.

97. How does sediment reduce visibility?

Suspended solids scatter light.

98. How does sediment change flow?

Shallowing and channel widening.

99. Examples of pollutants?

Metals, PFAS, pesticides, herbicides, road salts, nutrients, cyanotoxins.

100. What are PFAS?

Synthetic persistent chemicals (“forever chemicals”).