Upper Ocean Nutrient Limitation: processes, patterns and potential for change

Studies conducted during the past few decades have demonstrated that the productivity of the upper oceans is limited by the availability of a range of nutrients including nitrogen, iron and phosphorus. This, in turn, affects the storage of carbon in the oceans. However, several aspects remain to be fully understood. These include, for example, the nutrients that limit nitrogen fixation in the modern oceans and the role of trace elements other than iron. There is also a need to bring clarity to the term “limitation” itself: multiple uses of the term have resulted in confusion within the observational literature, and have hindered effective communication between researchers in different disciplines. With this in mind, this joint IGBP-SCOR (Scientific Committee on Oceanic Research) fast-track initiative aims to survey our current understanding of nutrient limitation in the upper oceans, identify gaps in knowledge and evaluate methodologies used to assess nutrient limitation. All potentially limiting nutrients (macronutrients such as nitrogen, micronutrients such as iron and organic nutrients such as vitamin B12) will be considered.

Coordinators

Mark Moore (National Oceanography Centre, Southampton), Matt Mills (Stanford University), Doug Wallace (SOLAS) and Emily Breviere (SOLAS)

Specific goals

1. To synthesise the current state of knowledge concerning patterns of upper ocean nutrient limitation, including identification of current observational gaps

2. Based on this synthesis, to recommend future avenues of research, taking specific account of the potential for past and future global change and linkages to the carbon cycle

3. To recommend a rigorous definitional framework for describing upper ocean nutrient limitation, with specific reference to multiple timescales and cross-disciplinary boundaries

4. To critically evaluate the techniques and methods currently used to assess upper ocean nutrient limitation

Products envisaged

1. Review article in the peer-reviewed literature (e.g. Science or Global Change Biology), presenting a broad synthesis

2. More detailed review articles on specific sub-topics, such as critical future changes in limiting nutrients

3. Report on the large-scale observational and/or modelling programmes. 

Meetings

·      A special session at AGU/ASLO Ocean Sciences meeting in Oregon (February 2010).

·      Workshop in November 2010 in the UK

* This initiative is also receiving support from the US Ocean Carbon and Biogeochemistry program (http://www.us-ocb.org/)