Impact of dust on biogeochemical processes in the East Mediterranean - PowerPoint PPT Presentation

Impact of dust on biogeochemical processes in the East Mediterranean Sea, case studies and gaps of knowledge Barak Herut Israel Oceanographic & Limnological Research Driving Force

The Levantine basin – Most Sensitive System Natural • Most Extreme S, T, Chl, Nut • LIW formation • Long term changes (S,T,O2,Nut) • Changes in circulation intensity Anthropogenic • Change in Nile floods and Damming • Suez Canal, shipping Levantine Basin • Marine Infrastructures • Climate change Nile Suez Delta Canal SSS SST SSS PP 2003/06/17

organic History of eutrophic/anoxic rich periods sapropel Sensitive system to Environmental Change

The Nile’s dams Suez canal • A series of dams were built on the Nile since the early 20 th century with the 1 st built in 1902. High Aswan • Since 1965 the Aswan High Dam Dam started to operate. Since than all sediments are accumulating in Lake Nasser. Suez canal, 1869 The opening of the Suez Canal 140 years ago opened the gates to a major one-way faunal invasion from the Red Sea to the SE Mediterranean and a major transfer of relatively more saline and nutrient-poor seawater.

Shifting sediment properties following Nile damming S N % >63  m size fraction The sedimentary regime is 0 20 40 60 80 0 20 40 60 80 0 20 40 60 80 Year 2000 undergoing major changes 1990 and consequently might 1980 1970 affect the living 1965 1960 1950 ecosystem. Aswan 1940 Damming 1930 1920 1910 1900 G / 33 m E / 40 m B / 40 m Pre–High 35 o 1890 Haifa Almogi-Labin & Herut At present Aswan Dam 32.8 33 o 0 20 מ ק 32.7 תוחילמ - יווש םיווק , םיה ינפב ( ) % % הפיח 32.6 1956 רבמטפס 0 Taninim 32.5 1956 2008 river 32.4 Nile floods and shifting 32.3 Netanya 32.2 SSS of the Israeli shelf 32.1 Tel Aviv ביבא לת 32 32 o 32 o 31.9 31.8 Hecht, 1992 Salinity <33 psu 39.85 psu 31.7 August 2008 Ashqelon ןולקשא (Hecht, 1956) 31.6 34.5 34.6 34.7 34.8 34.9 35

Shifting sediment properties following Nile damming  13 Corg (‰) % >63  m size fraction % Silt Mode % CaCO 3 TOC(wt.%) 0 20 40 60 0 20 40 60 0 50 100 0 10 20 -24 -22 -20 0 0.5 Year 2000 1990 1980 1970 1960 1950 1940 1930 1920 1910 1900 1890 2 4 6 8 10 Almogi-Labin, Herut % Al - Rapid sediment coarsening reflect sharp reduction in silt flux - Moderate and a delayed increase in CaCO 3 result from decrease in sediment dilution - The two step decrease in organic carbon and the gradual decrease in  13 Corg reflect significant depletion in nutrients and a change in the organic carbon source

Alien species in the Mediterranean: A Region at High Risk B. Galil

B. Galil

Israel coastal waters – activities in the new millennium Ports expansion Artificial islands constructions ימי רוטינב ךרוצהלארשיב Desalination plants Marine outfalls for brines Mariculture development Gas drilling Increase in marine transportation Power plants Red Sea – Dead Sea Water Conveyance Program

Impact of dust on biogeochemical processes in the East Mediterranean Sea, case studies and gaps of knowledge Barak Herut Israel Oceanographic & Limnological Research Driving Force

Atmospheric input of Nitrogen is high and increasing Global Emission to Atmosphere million ton Nitrogen/yr 80 70 60 50 40 30 20 10 0 2000 2030 Year

Measurements of short and long-term records of dry atmospheric deposition for the Eastern Mediterranean Sea (EMS) indicates a significant role of Mediterranean aerosols as a major supplier of macro and micro nutrients (N, P, Fe and other trace metals) to the Low Nutrient Low Chlorophyll EMS.

Haifa Erdemly Atmospheric Fluxes Heraklion

Atmospheric Nutrient Supply Assessment for East Mediterranean Fluxes in mmol m -2 yr -1 Nutrient Dry Wet Bioavailable 50 20 ~70 N P 1 0.3 ~0.7 The soluble dry fraction is dominant Sources : Herut et al., 1999, 2002, 2005; Krom et al. 2004; Kouvarakis et al. 2001; Markaki et al., 2003; Carbo et al., 2005;

Kocak et al., 2010

Krom et al., 2010

Leachability is dependent on aerosol sources Release of IN: Dust events << European aerosols IP solubility: Dust events << European aerosols Leachable N/P: Dust events << European aerosols West Mediterranean Dust Storm, 20 October 2001, R/V Meteor

Average N/P ratio of 500 bioavailable atmospheric y = -86 ln(x) + 900 R = 0.72 inputs is 80-120 400 LIN  LIP in m 3 air 300 200 500 100 Storm 400 Background Redfield LIN:LIP molar ratio 0 300 100 1000 10000 100000 ng Al in m 3 air 200 Herut et al., 2002 100 0 100 1000 10000 100000 Al ng m -3 air Carbo et al., 2005

Krishnamurthy et al., 2010 JGR requirement Biological The average elemental N/P requirement for many plankton species and for bulk organic matter in the oceans has been found to be relatively constant at 16 (mol/mol) [i.e., Redfield, 1934, 1958]

Anthropogenic Pb Angelidis et al., 2011, MPB

Kocak et al., 2012

Toxic Cu - # months Saharan aerosol Paytan et al., 2009 PNAS

• Trichodesmium accelerates the rate of iron dissolution from oxides and dust, through as yet unspecified cell-surface processes, and thereby increases cellular iron uptake rates. • Natural puff (ball-shaped) colonies of Trichodesmium are particularly effective at dissolving dust and oxides, attributed to efficient dust trapping in their intricate colony morphology, followed by active shuttling and packaging of the dust within the colony core. • Colony formation in Trichodesmium is an adaptive strategy that enhances iron acquisition from particulate sources such as dust.

Recent experimental studies have applied dust enrichments to bottle or mesocosm incubations of seawater from different oceanic regions to explore its biogeochemical impact. In the Mediterranean few on-board dust microcosm and a mesocosm experiment were performed with dust applied to surface seawater in the low-nutrient-low-Chlorophyll waters of the western Mediterranean (Corsica, www.obs-vlfr.fr/LOV/DUNE).

Dust Microscosm Experiment on board R.V. Aegaeo, May 2002 Bottle Dust Loading No (mg/L) 1 -- no dust control 2 -- no dust control Natural Dust 3 4.88 4 4.88 5 2.0 6 0.7 7 0.2 Pre-leached dust 8 4.94 9 4.75 10 1.95 11 0.69 12 0.21 Herut et al., 2005 DSR

250 0.6 Primary production (mgC/m 3 /h) y = 0.1011x + 0.0595 200 0.5 y = 31.106x + 38.923 2 = 0.9971 R 2 = 0.9979 R Chl a (ng/L) 0.4 150 FD FD 0.3 LD LD 100 Control Control T0 0.2 50 0.1 0 0.0 0 1 2 3 4 5 6 Dust concentration (mg/L) 0 1 2 3 4 5 6 Dust concentration (mg/L) 70 FD 19’-hexa LD 19’-hexa 60 5-fold increase in Chl-a and PP, Control 19'-hexa 50 Pigment (ng/L) linearly related to fresh dust gradient Control Zeax FD Zeax 40 LD Zeax 30 20 10 0 0 1 2 3 4 5 6 Herut et al., 2005 DSR Dust concentration (mg/L)

Dust Microscosm Experiment on board R.V. Aegaeo, May 2002 Parameters Response to fresh dust addition Dissolved Inorganic Nutrients Increase Dissolved Organic P (UVL) No change 33P turnover Increase Bacterial activity Increase Bacterial density No change Flow cytometry Variable Chl-a Increase Phytoplankton Variable Primary Production Increase Phytobiomass (HPLC) Increase Ciliates Variable Flagellates HNF-decrease, ANF-increase

Does a single dust storm have a fast impact? R.V. Aegaeo, May 2001

0.004 0.10 0.08 0.003 -1 -1 -2 d -2 d 0.06 LIN mmol m LIP mmol m 0.002 250 0.04 200 y = 31.106x + 38.923 0.001 2 = 0.9979 R 0.02 LIP Chl a (ng/L) 150 LIN FD LD 0.000 0.00 100 Control T0 129-31 131-33 133-34 134 134-36 136-37 ~0.08 mg dust/L 50 Julian day (8-16 May 2001) 10m mixed layer 0 0.020 100 0 1 2 3 4 5 6 Dust concentration (mg/L) 0.016 80 -1 -2 d -1 -2 d 0.012 60 TIP mmol m Al mg m 0.008 40 TIP 0.004 20 Al 0.000 0 129-31 131-33 133-34 134 134-36 136-37 Julian day (8-16 May 2001)

In-situ response : *Small detectable change in Chla Average Chla in top 15 m 0.045 *Release of P dust storm Probably grazed away 0.040 immediately by the *No detectable change in ‘hungry starved lions’ 0.035 Chla ug/l Bact. abundance. 0.030 *Maybe small increase 0.025 in Bact. activity. 0.020 *Sharp decline of 0.015 prochlorophytes. 1 1 1 1 1 1 1 1 0 1 2 3 4 5 6 7 - - - - - - - - M M M M M M M M a a a a a a a a y y y y y y y y - - - - - - - - Evidences of 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 micrograzing

BOUM Cruise - SESAME Ternon et al., 2011

Response to dust addition – microcosm experiments with surface seawater Red – significant increase, Green – insignificant change, Purple – significant decrease

Primary productivity response to dust addition – Med Sea Increase No change Decrease

Sohm et al., 2011 Nature Reviews

To better understand the interactions between natural and anthropogenic atmospheric deposition, community structure and biogeochemical cycling in LNLC areas a better quantification of key processes in surface waters is needed