Role of macrofauna and the impacts of natural and anthropogenic disturbance on sediment biogeochemical processes (Module 3)

Transcription

1 Biogeochemistry, macronutrient and carbon cycling in the benthic layer (BMCC) WP2 Role of macrofauna and the impacts of natural and anthropogenic disturbance on sediment biogeochemical processes (Module 3) Jan Geert Hiddink, Marija Sciberras Ruth Parker, Jasmin Godbold, John Aldridge & others

2 Over-arching aims WP2 Role of microbialmacrofaunal coupling in affecting sediment biogeochemical processes in cohesive and noncohesive sediments (Aim 3.1) Determine how anthropogenic drivers affect the microbialmacrofaunal couple and quantify the implications for C- and nutrient cycling (Aim 3.2)

3 Role of microbial-macrofaunal coupling in affecting sediment biogeochemical processes in cohesive and non-cohesive sediments (Aim 3.1) WP2

4 Task 3.1.1: To quantify macrofaunal activity in mediating microbial biogeochemical cycling 3. Biogeochemical processes C (DIC, DOC) and N (NO 2, NO 3, NH 3 /NH 4, PO 4, SiO 2 ) exchange rates (μmol m -2 h -1 ) Intact sediment cores from 4 regions (5 reps/region): mud sandy mud muddy sand sand Shipboard incubations: 6 days/region 1. Quantify macrofaunal assemblage structure and activity (sediment reworking & bioirrigation) 2. Microbial abundance and activity

5 Task 3.1.2: Determine the significance of functional traits for biogeochemical cycling in cohesive and non-cohesive sediments Existing North Sea datasets; new Celtic Sea sampling (March / April 2014; stations) Linking key variables and exploring relationships of state and functioning across substrates and regions Site A Linking structural and functional traits of the community LANDER 1 to Celtic Deep biogeochemical functions Site B B LANDER 2 S of Celtic Deep A LANDER 3 S of N of Haig Fras D C

6 e.g. large mollusc TRAITS Large-bodied Slow-growing Long-lived Low fecund Linking faunal traits and biogeochemistry: Which traits? Which biogeochemical variables? Regional scales and habitats? e.g. small worm TRAITS Small-bodied Fast-growing Short-lived High fecund Secondary production Large indiv biomass High indiv production Low turnover (productivity) Low P:B (y -1 ) Variable C and N storage within sediments Varies with habitat/sediment type Secondary production Low indiv biomass Low indiv production High turnover (productivity) HighP:B (y -1 )

7 Task 3.1.3: 1D ERSEM modelling WP2 Explore hypotheses concerning bioturbation/irrigation influence on geochemistry (e.g. oxic and denitrification depth) Help assess to what extent faunal community information can be used as a predictor for rates of nutrient and C recycling Carbon input, phytoplankton/detritus Compare predictions with output from Tasks and Org C Link back to developments in WP4 Recycle and consumption Benthic Community structure influence on anoxic boundary. After Pearson and Rosenberg, 1978

8 Determine how anthropogenic drivers affect the microbial-macrofaunal couple and quantify the implications for C- and nutrient cycling (Aim 3.2) WP2

9 Bottom trawling Climate change (OA and temperature)

10 Coupled denitrification Dn (µmol N/m2/h Task 3.2.1: Quantify chronic effects of trawling on benthic assemblage structure and biogeochemical cycling WP y = e x R 2 = Trawling pressure (satellite) Data collection: Irish Sea on RV Prince Madog 27 th June 6 th July 2014 North Sea 2015 (tbc) Ecosystem measures estimated: Sediment, carbon, O 2, redox and biological mixing (SPI), nutrients Rates DOU, nutrient fluxes, other (tbc)

11 Task 3.2.1: Quantify chronic effects of trawling on benthic assemblage structure and biogeochemical cycling WP2 Measures of benthic biodiversity Measures of ecosystem functioning Environmental parameters Box core samples Infauna community structure (diversity, abundance, biomass) Sediment reworking: luminophores Organic carbon, Chl-a content Other measurements of additional consortium members Porosity Sediment particle size O 2 profiles Pore-water nutrient profiles SPI-camera replicates Depth of arpd, burrowing depth

12 WP2

13 Task 3.2.2: Importance of the removal/addition of functionally important fauna on biogeochemical cycling as a result of trawling WP2 Prince Madog cruise (Summer 2015, tbc) & mesocosm experiments Cohesive sediments / Non-cohesive sediments Fishing effort: None High 5 box core (0.1m 2 ) samples 10 box core (0.1m 2 ) samples Mesocosm experiments Reference for biogeochemical processes in undisturbed sediments Treatment: Faunally depleted + add dominant missing fauna Control: Faunally depleted / Heavily trawled n = 5

14 Task 3.2.3: To determine vulnerability (sensitivity) of macromicrofauna coupled biogeochemical cycling to anticipated future environmental conditions 1. Quantify chronic effects of trawling on benthic assemblage structure and biogeochemical cycling 2. Determine vulnerability under anticipated future environmental conditions Intact sediment cores from 4 regions in Celtic Sea (Task 3.1.1) and trawled/untrawled regions in Irish Sea (Task 3.2.1) Laboratory incubations at present and anticipated future (2050) climatic conditio (temperature, CO 2.) 6 month incubations Macrofaunal assemblage structure and activity Microbial abundance and activity Biogeochemical processes

15 Task Modelling of the impact of faunal assemblage alteration by trawling and climate change on shelf sea sediment C- and nutrient-cycles Modelling to scale up locally observed effects of trawling pressure to regional effects on the ecosystems (assemblage/biogeochemical relationships) Change scenarios of assemblage shifts (ranked by sensitivity to trawling by traits or observations) GIS modelling methodologies: mapping functional change given differing fleet distributions

16 Carbon fraction changes (2 North Sea sites and species loss) Species left