Photokinetic adaptation of sea-ice algae

Metadata record for data from ASAC Project 2702
See the link below for public details on this project.

Sea-ice algae are the basis of the Antarctic food web and are essential for healthy functioning of the Antarctic ecosystem. These algae exploit a unique niche within this extreme environment. Using advanced photosynthetic analysis we will examine the mechanisms which influence the productivity of sea-ice algae.

The objective of this project is to understand the processes of light acclimation and photo-protection employed by sea-ice algae under extremely low temperature conditions. Several new hypotheses have been proposed in a recent review of low temperature acclimation of higher plants (Oquist and Huner, 2003). To further understand the remarkable tolerance of sea-ice algae to photoinhibition, we propose to test several of these hypotheses. Sea-ice algae fix inorganic carbon that forms the basis of the Southern Ocean food web. Sea ice covers up to 20 million km2 of the Southern Ocean each year. Global climate change will decrease the sea-ice thickness and distribution (IPCC, 2001); however subtle changes in temperature and light penetration will also have profound negative impacts on the photosynthetic efficiency of the sea-ice microalgae before any macroscale changes take place. Sea-ice algae are essentially the only food source for invertebrates and fish for up to nine months of the year. During winter and spring, krill (Euphausia sp.) have been observed feeding directly on sea-ice algae. Further, changes in sea-ice productivity will have a cascade effect further up the food web. Therefore, understanding how physical driving forces (temperature and light) affect sea-ice algae productivity will be critical to our ability to predict the effects of climate change and sustainably manage this unique and vulnerable ecosystem.

Our primary objective is: To understand the processes of light acclimation and photo-protection employed by sea-ice algae under extremely low temperature conditions, with an aim to better understanding the potential implications of global climate change on the Antarctic sea-ice ecosystem.

ASAC项目2702数据集元数据记录，请点击下方链接查看该项目的公开详情。

海冰藻类（sea-ice algae）是南极食物网（Antarctic food web）的基础，对南极生态系统（Antarctic ecosystem）的健康运转至关重要。这类藻类在该极端环境中占据独特生态位。本研究将采用先进光合分析技术，探究影响海冰藻类生产力的调控机制。

本项目旨在阐明极端低温条件下海冰藻类所采用的光适应（light acclimation）与光保护（photo-protection）过程。近期一篇关于高等植物低温适应的综述（Oquist与Huner，2003）中提出了若干新假说。为进一步理解海冰藻类对光抑制（photoinhibition）的卓越耐受能力，我们计划验证其中部分假说。海冰藻类可固定无机碳，该过程构成了南大洋（Southern Ocean）食物网的基础。南大洋每年有多达2000万平方千米的区域被海冰覆盖。全球气候变化将导致海冰厚度与分布范围缩减（政府间气候变化专门委员会，Intergovernmental Panel on Climate Change, IPCC，2001）；但在出现任何宏观尺度变化之前，温度与光穿透性的细微变化，就会对海冰微藻的光合效率产生显著负面影响。在每年长达九个月的时间里，海冰藻类几乎是无脊椎动物与鱼类的唯一食物来源。观测发现，冬季与春季期间，磷虾（Euphausia sp.）会直接以海冰藻类为食。此外，海冰藻类生产力的变化，会在食物网中产生级联效应。因此，阐明温度与光照这两类物理驱动因子如何影响海冰藻类的生产力，对于我们预测气候变化影响、可持续管理这片独特且脆弱的生态系统至关重要。

本项目的核心目标为：阐明极端低温条件下海冰藻类所采用的光适应与光保护机制，以期更好地理解全球气候变化对南极海冰生态系统的潜在影响。