Organic matter fluxes to the nectobenthonic communities of the Majorca continental slope (Western Mediterranean):

influence of the environment on the spatio-temporal variability

Pasqual, C., Calafat, A., Monserrat, S., Flexas, M.M., Amores, A., López-Fernández, P., Pusceddu, A., López-Jurado J. L., Balbín, R.

INTERNATIONAL WORKSHOP ON ENVIRONMENT, ECOSYSTEMS, DEMERSAL RESOURCES AND FISHERIES

AUDITORIUM PARC BIT, PALMA, MALLORCA (SPAIN), 14-16 NOVEMBER 2012

Introduction

• Vertical particle flux (marine snow) is an important source of OM to the deep-sea ecosystems

• The transference of OM / (biological pump) is driven by physical processes that enhance the particle production and settling along the water column

Introduction

• Vertical particle flux (marine snow) is an important source of OM to the deep-sea ecosystems

• The transference of OM / (biological pump) is driven by physical processes that enhance the particle production and settling along the water column

• At continental margins, the lateral transference of material via nepheloid layers becomes also an important source of particles and OM (continental shelf pump)

Introduction

• Vertical particle flux (marine snow) is an important source of OM to the deep-sea ecosystems

• The transference of OM / (biological pump) is driven by physical processes that enhance the particle production and settling along the water column

• At continental margins, the lateral transference of material via nepheloid layers becomes also an important source of particles and OM (continental shelf pump)

OBJECTIVES

• Describe particle flux and, concretely, the organic matter flux and quality at Sóller and Cabrera

• Identify the environmental factors that control its dynamics

Methodology

Mooring line:Currentmeters

CDT

Sediment traps

Methodology

Mooring line:Currentmeters

CDT

Sediment trapsNovember 2009 to February 2011 10 day sampling resolution

Methodology

• Total mass fluxes (TMF) and major components composition >>> quantitative and qualitative information of material flux to the nectobenthonic communities

Swimmersremoval

Freeze-dry

TMF

Opal CaCO3LITHOGE

NICSOM

Major components:

Methodology

• Total mass fluxes (TMF) and major components composition >>> quantitative and qualitative information of material flux to the nectobenthonic communities

• The biochemical composition of the OM is used to gain information about the origin and quality of that OM:Proteins

Carbohydrates

Lipids

chlorophyll-a and phaeopigments

δ15N and δ13C

Swimmersremoval

Freeze-dry

TMF

Opal

Proteins

Carbohydrates

Lipids

Chloropigments

δ15N and δ13C

CaCO3LITHOGE

NICSOM

Major components:

TMF and Environmental factors

TMF and Environmental factors

Total mass flux was higher at Sóller than Cabrera (317.95 ± 146.69 mg m-2 d-1 and 161.80 ± 97.06 mg m-2 d-1 respectively).

Sediment entering the sediment traps shows temporal variability suggesting that the fluxes of material arriving to the nekton-benthonic communities are under the infuence of different environmental factors

TMF and Environmental factors

• Correlation (Pearson correlation) between total mass fluxes and atmospheric, oceanographic and biological variables

Oceanographic f.:Fronts / Eddies

Atmospheric f.:Wind

Water column destabilizationUpwelling

Sediment resuspension

Input of nutrients

Increase PP, grazing activity...(BIOLOGICAL PUMP)

IncreaseTMF

TMF and Environmental factors

• Correlation (Pearson correlation) between total mass fluxes and atmospheric, oceanographic and biological variables

• Atmospheric variables considered are wind speed and wind direction (from Dragonera Buoy)

• Oceanographic variables considered are water temperature, salinity (form CTD) water velocity at 500 and 900 m water depths, derived Kinetic energy (KE) and turbidity (from current meters )

• Surface Chl a concentrations as a biological variable indicating the primary productivity (obtained from Giovanni Ocean Color Radiometry NASA)

Oceanographic f.:Fronts / Eddies

Atmospheric f.:Wind

Water column destabilizationUpwelling

Sediment resuspension

Input of nutrients

Increase PP, grazing activity...(BIOLOGICAL PUMP)

IncreaseTMF

Pearson Correlation

Correlation is significant at the 0.01 level (2-tailed)/ 0.05 level (2-tailed)

Sóller

Sóller

Anticyclonic structure: November until the end of February 2010 (Balbín et al., 2012)

Maximum of SSH was over the Sóller mooring position from middle January to nearly the end of February

Sóller

Anticyclonic structure: November until the end of February 2010 (Balbín et al., 2012)

Maximum of SSH was over the Sóller mooring position from middle January to nearly the end of February

• 6/12/09: Intensification of the along slope current.

• 16/2/10 across slope component

Sóller

PVD Sóller 500

PVD Sóller 900

Sóller

PVD Sóller 500

PVD Sóller 900

Sóller

Reversal of the current at 500 m whereas at 900 m it is characterized by current fluctuations across and along slope.

PVD Sóller 500

PVD Sóller 900

Sóller

Reversal of the current at 500 m whereas at 900 m it is characterized by current fluctuations across and along slope.

The same effect on particle fluxes may be established also for the anticyclonic eddy that took place during November-December 2010 and June-July 2010

PVD Sóller 500

PVD Sóller 900

Sóller

Peaks in mass fluxes are associated with anticyclonic eddy

Sóller

Peaks in mass fluxes are associated with anticyclonic eddy

The increase in particle fluxes may be associated to two origins:

1. The mesoescale features may increasing the primary productivity

and /or

2. Favor the sediment resuspension and formation of nepheloid layers. The downwelling waters (as indicate (vKE)) transport resuspended upslope material down to Sóller station (900 m)

Sóller

Pearson Correlation

Correlation is significant at the 0.01 level (2-tailed)/ 0.05 level (2-tailed)

Cabrera

Major correlation has been found between Chl a and TMF (0.72). Chlorophyll a is strongly positively correlated with wind vector (0.682)

Cabrera

Major correlation has been found between Chl a and TMF (0.72). Chlorophyll a is strongly positively correlated with wind vector (0.682)

TMF at Cabrera stations seem to be triggered by wind episodes that enhance primary production and thus the settling of a pelagic sediment

Cabrera

TMF and Environmental factors

CONCLUSIONS

• At Sóller the mesoescale variability of the Balearic current enhance the settling of material

• Eddie/fronts may affect the material arriving to the necto-benthic slope environment / deep sedimentation in by increasing the primary productivity and/or favoring the sediment resuspension and formation of nepheloid layers that ultimately increase TMF

• TMF at Cabrera stations seem to be triggered by wind events that enhance primary production and thus the pelagic settling

TMF and Environmental factors

CONCLUSIONS

• At Sóller the mesoescale variability of the Balearic current enhance the settling of material

• Eddie/fronts may affect the material arriving to the necto-benthic slope environment / deep sedimentation in by increasing the primary productivity and/or favoring the sediment resuspension and formation of nepheloid layers that ultimately increase TMF

• TMF at Cabrera stations seem to be triggered by wind events that enhance primary production and thus the pelagic settling

QUESTIONS

• What are the effects on OM flux and quality of those different environments?

Major components and OM flux and composition

Major components

Major components

At Sóller are characterized by higher lithogenic fraction content than Cabrera

At Cabrera fluxes has higher percentage of OM and opal than at Sóller

Major components

At Sóller are characterized by higher lithogenic fraction content than Cabrera

At Cabrera fluxes has higher percentage of OM and opal than at Sóller

The composition of the samples reinforce the hypothesis of a resuspended origin of the material due to the high lithogenic content at Sóller vs a more “pelagic” origin of the material at Cabrera

OM Biochemistry

Terrigenous plants and marine organisms present different C/N, δ13C and δ15N values that are commonly analyzed in order to identify the origin of OM

Marine Terrigenous

N/C ~0,14 < 0.11

δ15N 5‰ // 0‰ 0‰

δ13C -22 to -19‰ -26‰ // -14‰

OM Biochemistry

Terrigenous plants and marine organisms present different C/N, δ13C and δ15N values that are commonly analyzed in order to identify the origin of OM

Isotopic data and N/C suggest thatOM is mostly from a marine origin

Marine Terrigenous

N/C ~0,14 < 0.11

δ15N 5‰ // 0‰ 0‰

δ13C -22 to -19‰ -26‰ // -14‰

OM Biochemistry

Chlorophyll a is produced by phytoplankton in the surface waters, and is quickly degraded

Its concentration may be indicative of inputs of fresh marine organic matter

Seasonal pattern

OM Biochemistry

Chlorophyll a is produced by phytoplankton in the surface waters, and is quickly degraded

Its concentration may be indicative of inputs of fresh marine organic matter

Seasonal pattern

Thus, data indicate a fresh marine organic matter inputs during phytoplankton blooms

Biochemistry of the OM

The biopolymeric fraction of organic carbon (BPC, sum of protein, carbohydrate and lipid carbon equivalents) is considered to be the fraction of OC potentially available to the benthic consumers

Higher nutritional value of OM after TMF peaks due to anticyclonic eddyes and associated with fresh marine organic matter inputs during phytoplancton blooms

Proteins are among the most labile biochemical compounds of OM in marine environments their concentrations relative to OC and other more recalcitrant organic constituents have been used as tracer of the degradation state of OM

Lower values at Cabrera than Sóller suggesting that at Cabrera ground is arriving OM with lower nutritional value

In Sóller: more energetic environment > higher setlling velocity of particles > lower degradation

OM Biochemistry

Mediterranean context

Samples from sediment traps have been compared with sediment trap data from studies located at the Mediterranean Basin

Mediterranean context

Mediterranean context

Lithogenic and OC% in the range of basin (or Island environment) values

Conclusions

Particle fluxes and composition values arround Mallorca Island are in the range of valuesdetected in basin or islands (Creta) environments of the Mediterranean

TMF and its composition have allowed detect the major physical drivers of particle fluxes at each site (mesoscale variability at Sóller and primary production at Cabrera) and thus explain more accurately the temporal variability of each environment

Conclusions

Particle fluxes and composition values arround Mallorca Island are in the range of valuesdetected in basin or islands (Creta) environments of the Mediterranean

TMF and its composition have allowed detect the major physical drivers of particle fluxes at each site (mesoscale variability at Sóller and primary production at Cabrera) and thus explain more accurately the temporal variability of each environment

• Eddies/fronts may affect the material arriving to the necto-benthic slope environment by increasing the primary productivity and/or favoring the sediment resuspension and formation of nepheloid layers that ultimately increase TMF

• TMF at Cabrera station seem to be triggered by wind episodes that enhance primary production and thus the pelagic settling

• Higher nutritional value of OM associated with fresh marine organic matter inputs during phytoplankton blooms at both Sóller and Cabrera

• At Sóller, the more energetic environment may induce higher setlling velocity of particles and thus lower degradation of OM. What about plankton at both sites?

Outputs

PUBLICATIONS:

• Organic carbon fluxes to the nekton-benthic communities of the Mallorca continental slope. Comparison within a Mediterranean context. Pasqual, C., Calafat, A., López-Fernández, P., Monserrat, S., Pusecddu, A., Amores, A., Flexas, M.M.

• Influence of eddies on the spatio-temporal variability of mass fluxes on the Mallorca continental slope (Western Mediterranean). Pasqual, C., Amores, A., Monserrat, S., Flexas, M.M., Calafat, A.