2016 SoE Marine Chapter - State and Trends - Primary productivity

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "The state and trends of ecological processes – primary productivity". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record.----------------------------------------DESCRIPTION OF ECOLOGICAL PROCESS FOR EXPERT ASSESSMENTSatellite data for ocean colour provides the most comprehensive assessment of phytoplankton biomass (PB) and primary production (PP). The method works very well in oceanic waters but PB and PP can be overestimated in regions where runoff or resuspension affects water colour (near land, especially near large tropical rivers). In general phytoplankton biomass and primary production (PP) are low around Australia. Typically both BP and PP are greatest near the coast tending to decline with distance from shore. Offshore oceanic waters north of ~30°S generally have low rates of PP, < 0.2g C m-3 d-1. From 1997 to 2015 the greatest rates of PP have been found near shore, in the marginal Arafura Sea and southern Tasman Sea. The biomass and productivity of the oceans is dependent upon the magnitude and timing of nutrient supply. The more tropical oceans of northern Australia tend to be strongly stratified restricting nutrient resupply from depth (Chavez et al. 2011). Australia is one of the driest continents with very low and highly erratic runoff (McMahon, 1982) so nutrient supply from the land is also low.DATA STREAM(S) USED IN EXPERT ASSESSMENTData used in this assessment are computed from the level 3 (L3) daily global products using one merging method. PP was computed from merged monthly L3 products using the algorithms developed by Antoine and Morel (1996). Details can be found at http://www.globcolour.info/products_description.html----------------------------------------2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details]• 2016 •Assessment grade: GoodAssessment trend: ImprovingConfidence grade: Adequate high quality evidence and high level of consensusConfidence trend: Adequate high quality evidence and high level of consensusComparability: Grade and trend are comparable to the 2011 assessment• 2011 •Assessment grade: Very goodAssessment trend: StableConfidence grade: Limited evidence or limited consensusConfidence trend: Limited evidence or limited consensus----------------------------------------CHANGES SINCE 2011 SOE ASSESSMENTThis assessment uses observations from a range of spatial and temporal scales that allows a much better assessment of current state and trends to be made.