Abstract:

Twenty plots (2.1 m x 2.1 m) were established in April 2014 in northern Barataria Bay Louisiana along a saltmarsh shoreline (29.44105oN, -89.93337oW) that was heavily oiled by the Deepwater Horizon oil spill but for which vegetative recovery had not occurred. Five rectangular blocks (~12 m - 30 m) were established within ~3 m of the shore, and treatments were initiated within each block. The two factors considered here were vegetative planting, with or without Spartina alterniflora, and fertilization, with or without slow-release fertilizer. Treatments were (1) unmanipulated (no transplants and no fertilizer) to serve as controls, (2) transplants only, (3) fertilizer only and (4) a combination of transplants and fertilizer. Spartina plants were transplanted at a density of 3-5 stems/plug, spaced 30 cm apart and planted 10 cm deep. Slow-release fertilizer (15% N, 8% P2O5 and 11% K2O) was applied twice a year at a rate of 326 kg N/ha/yr, 76 kg P/ha/yr and 198 kg K/ha/yr. Biological samples were collected at various times after the plots were initiated. Microalgae: A hand-held corer (inner diameter = 1.2 cm) was used to take two sediment cores to a depth of 3 mm within the sampling quadrat. The two cores were combined in a single sample container and immediately frozen on dry ice. Photosynthetic pigments were extracted from entire sediment samples with 4 ml of 100% acetone. High pressure liquid chromatography was used to examine photosynthetic pigment concentration and composition. Chlorophyll a is used here as a proxy for microalgal biomass. Infauna: A hand-held corer was used to take two sediment cores to a depth of 2 cm from each plot. Both cores were combined into a single sample cup and fixed in 4% formalin in the field. Cups were shaken to break up soil clumps and to mix with formalin. In the laboratory, samples were sieved through a 500 µm sieve stacked on top of a 63 µm sieve. All material, including roots, rhizomes and macrofauna, retained on both sieves was preserved for analysis of macroinfauna and meiofauna.

Suggested Citation:

John Fleeger, Maria Rita Riggio, David Johnson. 2017. Macroinfauna and meiofauna abundance and diversity following restoration efforts, Barataria Bay, April 2014 - May 2016. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7X928BF

Publications:

Johnson, D. S., Fleeger, J. W., Riggio, M. R., Mendelssohn, I. A., Lin, Q., Graham, S. A., … Hou, A. (2018). Saltmarsh plants, but not fertilizer, facilitate invertebrate recolonization after an oil spill. Ecosphere, 9(1), e02082. doi:10.1002/ecs2.2082

Purpose:

To examine techniques in restoration after oil spills. Fertilization and plantings (of Spartina and Juncus) were conducted in a crossed experimental design.

Data Parameters and Units:

Replicate core samples were taken in experimental plots. Data include meiofauna (density data per core and standardized to per 10 cm2), macroinfauna (density data per core and standardized to per m2) and chlorophyll a concentration (ug per cm2). Columns are names of various taxa and include one copepod species (Nannopus palustris) and on polychaete species in the genus Capitella. Cruise, Treatment number, Block, Treatment (J+ = addition of Juncus, S+ = addition of Spartina), Spartina (S+ planted; S- not planted) Juncus (J+ planted; J- not planted), Nutrients N+ nutrients added, N- no nutrients added), Sample, Sieve fraction (mm, meio or macro), Species (ind/core or ind/10 cm^2 or ind/m^2), Mean, Standard error, Number of copepod spp, Chlorophyll a (ug/cm^2), Sample, Total macrofauna (ind/m^2)

Methods:

Twenty restoration plots (2.1 m x 2.1 m) were established in April 2014 in northern Barataria Bay Louisiana along a saltmarsh shoreline (29.44105oN, -89.93337oW) that extended over a linear distance of ~100 m. Five rectangular blocks (~12 m - 30 m) were established within ~3 m of the shore, and six restoration treatments were initiated within each block. The treatments were (1) unmanipulated (no transplants and no fertilizer) to serve as controls, (2) transplants only, (3) fertilizer only and (4) a combination of transplants and fertilizer. Treatments with Juncus were also planted, with and without nutrients. Spartina (up to 90 cm tall) plants were transplanted in designated plots at a density of 3-5 stems/plug, spaced 30 cm apart and planted 10 cm deep with a total of 64 plugs for each plot. Slow-release fertilizer (Osmocote Plus with 15% N, 8% P2O5 and 11% K2O) was applied twice a year (April and September) to designated plots at a rate of 326 kg N/ha/yr, 76 kg P/ha/yr and 198 kg K/ha/yr A hand-held corer (inner diameter = 3.5 cm) was used to take two sediment cores to a depth of 2 cm at haphazardly selected locations at each plot or station to sample the fauna. Both cores were combined into a single sample cup Samples were sieved through a 0.5 mm and 63 um screen, and fauna retained on the 63 screen are meiofauna while those retained on the 0.5 mm sieve are macrofauna . Counts refer to direct counts of a taxon; standardized is density (ind 10cm-2) for meiofauna and ind m-2 for macrofauna. Treatment codes are: J+ = addition of Juncus, S+ = addition of Spartina, N+ = fertilization.

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