Benthic foraminifera from the Ría de Vigo and the adjacent continental shelf

Study Extent

The Ría de Vigo is an elongate, funnel-shaped embayment located in the NW of the Iberian Peninsula. It is connected to the open ocean through a northern channel that is 2.5 km wide with a maximum depth of 25 m and a southern channel that is 5 km wide with a maximum depth of 67 m. The shallowest and the innermost part of the ría behaves as an estuary dominated by tides. The subaqueous sediments are composed of silt and clay with small amounts of sand and minor amounts of gravel. The rest of the Ría de Vigo is under the oceanic influence. Around the central ría axis, in the deepest areas, surface sediments consist mainly of organic-rich mud, whereas near the ría margins and in the outermost parts, sand and gravel occur. The ría is under the influence of shelf winds which modify the typical two-layer residual circulation pattern characteristic of partially mixed estuaries. Upwelling-favourable northerly winds that predominate from March–April to September–October enlarge the positive residual circulation and increase primary production in the rias. During the rest of the year downwelling favourable southerly winds prevail and the primary production is significantly lower. Sediment samples for the study of benthic foraminifera have been collected along the central axis and northern margins of the Ría. In the outermost part, samples include coarse-grained sediments from the northern and southern channels and a few stations in Baiona Bay. The continental shelf samples extend from the mouth of the Ría to the continental shelf at the mouth of the Miño estuary.

Sampling

Sampling was carried out in 1989 (Baiona bay, 8 stations), 1991/1994 (shelf, 17 stations) and 1998 (Ría de Vigo, 27 stations). Shelf and Baiona bay samples were collected using a Shipek drag and the first 0-1 or 0-2 cm of the sediment was selected for foraminiferal analysis. Samples from the Ria de Vigo were collected using a box corer during two contrasting environmental conditions (upwelling and downwelling). Each box core was sectioned into 1 cm thick slices of approximately 50cc, down to 9 cm sediment depth. The examined sediment thickness varied between stations. In the cases of the shelf and Ria de Vigo, samples were Rose-Bengal stained, which allowed to distinguish between considered living (stained) foraminifera and dead (unstained) foraminifera.

Method steps

1. In the laboratory the sediment was wet sieved and the residue dry weighted and examined for the quantification of benthic foraminiferal species. The thickness of the sediment studied, the laboratory methodology and size fraction in which benthic foraminifera were studied are indicated in the column "dynamicProperties".

N/A

1. Reophacidae
   rank: family
2. Monothalamea
   rank: class
3. Rosalinidae
   rank: family
4. Cornuspiridae
   rank: family
5. Mississippinidae
   rank: family
6. Vaginulinidae
   rank: family
7. Melonidae
   rank: family
8. Planulinidae
   rank: family
9. Robertinida
   rank: order
10. Chromista
    rank: kingdom
11. Astrononionidae
    rank: family
12. Buliminidae
    rank: family
13. Lacustrinellidae
    rank: family
14. Globothalamea
    rank: class
15. Gavelinellidae
    rank: family
16. Bolivinitidae
    rank: family
17. Stainforthiidae
    rank: family
18. Elphidiidae
    rank: family
19. Planorbulinidae
    rank: family
20. Buliminellidae
    rank: family
21. Tubothalamea
    rank: class
22. Robertinidae
    rank: family
23. Cibicididae
    rank: family
24. Haynesinidae
    rank: family
25. Chilostomellidae
    rank: family
26. Virgulinellidae
    rank: family
27. Ophthalmidiidae
    rank: family
28. Glabratellidae
    rank: family
29. Textulariidae
    rank: family
30. Asterigerinatidae
    rank: family
31. Globobuliminidae
    rank: family
32. Ellipsolagenidae
    rank: family
33. Nouriidae
    rank: family
34. Eponididae
    rank: family
35. Remaneicidae
    rank: family
36. Rotaliida
    rank: order
37. Lagenidae
    rank: family
38. Patellinidae
    rank: family
39. Haplophragmoididae
    rank: family
40. Pseudoparrellidae
    rank: family
41. Ceratobuliminidae
    rank: family
42. Vaginulinida
    rank: order
43. Prolixoplectidae
    rank: family
44. Ammoniidae
    rank: family
45. Siphogenerinoididae
    rank: family
46. Polymorphinida
    rank: order
47. Nodosariidae
    rank: family
48. Miliolidae
    rank: family
49. Discorbinellidae
    rank: family
50. Trochamminidae
    rank: family
51. Rotaliellidae
    rank: family
52. Polymorphinidae
    rank: family
53. Cancrisidae
    rank: family
54. Spiroplectamminidae
    rank: family
55. Ammosphaeroidinidae
    rank: family
56. Spiroloculinidae
    rank: family
57. Ammodiscidae
    rank: family
58. Eggerellidae
    rank: family
59. Nodosariida
    rank: order
60. Sphaeroidinidae
    rank: family
61. Uvigerinidae
    rank: family
62. Saccamminidae
    rank: family
63. Nodosariata
    rank: class
64. Foraminifera
    rank: phylum
65. Spirillinidae
    rank: family
66. Acervulinidae
    rank: family
67. Cassidulinidae
    rank: family
68. Rhabdamminidae
    rank: family
69. Spirillinida
    rank: order
70. Textulariida
    rank: order
71. Pseudobolivinidae
    rank: family
72. Hauerinidae
    rank: family
73. Siphoninidae
    rank: family
74. Astrorhizida
    rank: order
75. Cribrolinoididae
    rank: family
76. Discorbidae
    rank: family
77. Nubeculariidae
    rank: family
78. Alabaminidae
    rank: family
79. Epistominidae
    rank: family
80. Miliolida
    rank: order
81. Lituolida
    rank: order
82. Nonionidae
    rank: family
83. Discamminidae
    rank: family
84. Annulopatellinidae
    rank: family

Ría de Vigo (NW Iberian margin) and the adjacent continental shelf.