Past and current climate change has affected the food sources in the surface waters in the North Pacific Ocean.
(From Phys.com) — New research by Lawrence Livermore National Laboratory and colleagues at the University of California, Santa Cruz, University of Colorado and Universität zu Kiel in Germany, have found that there are distinct differences in how plankton respond to climate over the last 1,000 years.
The North Pacific Subtropical Gyre, the largest continuous ecosystem on Earth, has undergone major shifts in phytoplankton community composition associated with large-scale regional climate change. These findings have major implications for understanding past and future changes in open ocean productivity and food web dynamics, the efficacy of the biological pump and ocean biogeochemical cycling. A major finding is that the current North Pacific Subtropical Gyre plankton regime, characterized by enhanced nitrogen-fixing cyanobacterial production (a process in which algae and diatoms turn gaseous nitrogen into a food source), appears to have started around the end of the Little Ice Age and the beginning of the Industrial Era, and is likely unprecedented in the past 1,000 years.
By using samples of Hawaiian gold corals (Kulamanamana haumeaae), which are extraordinarily long-lived, and useful paleo-environmental archives, the team used a new technique to analyze compound-specific individual amino acids found in the coral’s organic skeleton. “To reconstruct past plankton community composition dynamics, we applied a cutting-edge compound-specific stable isotope fingerprinting approach to deep-sea corals,” said lead author Kelton McMahon.
Read the full article here: http://phys.org/news/2015-12-scientists-shifts-climate-sensitive-plankton-millennium.html