STATEMENT OF EVIDENCE OF LINCOLN MACKENZIE FOR OMV NEW ZEALAND LIMITED PRIMARY PRODUCTIVITY, PLANKTON, TOXIC ALGAE AND NUTRIENT PATHWAYS

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1 STATEMENT OF EVIDENCE OF LINCOLN MACKENZIE FOR OMV NEW ZEALAND LIMITED PRIMARY PRODUCTIVITY, PLANKTON, TOXIC ALGAE AND NUTRIENT PATHWAYS

2 The South Taranaki Bight is one of the most productive regions of New Zealand s coastal seas (from Knight & Jiang 2009)

3 The South Taranaki Bight/Western Cook Strait water-column ecosystem is dynamic and biologically productive

any small changes due to the discharge of drilling

4 15 Oct 2014 The high temporal and spatial variability in plankton biomass and productivity, are likely to make any small changes due to the discharge of drilling effluents insignificant on a local and regional scale 22 Oct 2014

5 Variability of phytoplankton biomass (chlorophyll a) in the South Taranaki Bight

6 Schematic diagram of the Kahurangi upwelling. From Kibblewhite et al Maui Development Environmental Study Report on Phase Two

plume matures, resulting in an increased biomass of

7 The Kahurangi plume food chain Successional changes in plankton communities take place as the Kahurangi plume matures, resulting in an increased biomass of krill ( Nyctiphanes australis) in eastern regions.

8 Composite satellite image of chlorophyll a concentrations in the south Taranaki Bight, Jan-Feb From Torres et al. (2014)

9 Satellite images of sea surface temperature showing the intermittent nature of the cold water plume associated with Kahurangi upwelling

10 Phytoplankton productivity at the Maari platform Temperature stratification and the depth of mixing in the surface layer controls the availability of light and nutrients to phytoplankton There will be seasonal cycles of stratification and productivity in the water column at the Maari field. Spring bloom; summer low nutrients; autumn productivity peak; winter high nutrients (nitrate) low biomass. Changing weather and oceanographic conditions (e.g. influence of the Kahurangi upwelling) will affect timing and magnitude of seasonal production cycles Against this background any small perturbations from the drilling discharge (e.g. turbidity) is unlikely to have a detectable effect on productivity

11 Toxicity of drilling wastes to phytoplankton and zooplankton Neff (1987) : water column organisms are not exposed to drilling fluids at sufficiently high enough concentrations to elicit acute or sub-lethal responses. Neff et al (2000): The effects of SBF cuttings on pelagic organisms are expected to be even less than those of WBFs. due to low inherent toxicity and rapid clumping and settling. Neff (2005): Because of the rapid dilution of the drilling muds and cuttings plume in the water column, harm to communities of water column plants and animals is unlikely and has never been demonstrated

12 Toxicity of drilling wastes to phytoplankton and zooplankton US Environmental Protection Agency study (ODCE, 2012): Offshore field studies have shown that drilling fluids discharged to open ocean waters generally are diluted to low concentrations at which they are not expected to produce adverse effects in water column organisms. Experimental studies (e.g. Vik et al. 1996) have shown that SBM base chemicals are not very toxic to phytoplankton and zoo plankton assay species identical or very similar to those present in the South Taranaki Bight. Potentially toxic metals are unlikely to present a hazard to planktonic organisms (Neff 2010).

13 Effects on plankton productivity by oil drilling discharges Large literature on the impact of oil spills on productivity of plankton communities. In many cases it has been difficult to distinguish natural variability from oil spill effects. Much less literature on impact of drilling discharges, presumably because of lesser effects. Alldredge et al. (1986) most quoted experimental study testing drilling mud ingredients on phytoplankton productivity: concluded that drilling discharges did not significantly affect primary production of phytoplankton where rapid dilution occurred. WBMs similar though SBMs used in their experiments were cruder mixes than currently used (i.e. Saraline 185V) Fucik & El-Sayed (1979) Field study found no detectable effect on phytoplankton production and standing crop in the Gulf of Mexico oil field regions after 40 years of activity.

14 Turbidity of the discharge plume Turbidity has the potential to effect phytoplankton productivity through light reduction The total discharge volume of muds and cuttings is very small in comparison to water flows beneath the rig. There is rapid settling of most coarse cuttings and rapid dispersion of fines in the plume in this high energy open-ocean environment Turbidity effects will be small and insignificant in comparison to natural sources of turbidity in the wider environment.

15 Summary The South Taranaki Bight is a highly dynamic and productive region. The Kahurangi upwelling has an important effect on the water column nutrient pathways and plankton communities in the vicinity of the Maari field. The international evidence suggests that the inherent toxicity of currently used WBM and SBM constituents to phytoplankton and zooplankton is low. Their effects are further minimised by their rapid flocculation, dilution and dispersal in open ocean situations. The turbidity of the discharge plume is expected to be of very little or no significance with respect to phytoplankton productivity. There is no evidence to suggest that past oil drilling or production in the Maui or Maari fields are in any way associated with toxic algal blooms on the North Island west coast. In my opinion the effect of the Maari drilling discharge on primary production, plankton, toxic algae and nutrient pathways will be no more than minor.

Long-term Marine Monitoring in Willapa Bay. WA State Department of Ecology Marine Monitoring Program

Long-term Marine Monitoring in Willapa Bay WA State Department of Ecology Marine Monitoring Program Ecology s Marine Waters Monitoring Program Goal: establish and maintain baseline environmental data Characterize