Data: The roles of sea-ice, light and sedimentation in structuring shallow Antarctic benthic communities

Data repository for the paper:

"The roles of sea-ice, light and sedimentation in structuring shallow Antarctic benthic communities"
Graeme F. Clark, Jonathan S. Stark, Anne S. Palmer, Martin J. Riddle, Emma L. Johnston.
PLoS ONE

Data are boulder communities (epifauna), annual light budgets, and sediment traps. See the paper for more details.

ABSTRACT
On polar coasts, seasonal sea-ice duration strongly influences shallow marine environments by affecting environmental conditions, such as light, sedimentation, and physical disturbance. Sea-ice dynamics are changing in response to climate, but there is limited understanding of how this might affect shallow marine environments and benthos. Here we present a unique set of physical and biological data from a single region of Antarctic coast, and use it to gain insights into factors shaping polar benthic communities. At sites encompassing a gradient of sea-ice duration, we measured temporal and spatial variation in light and sedimentation and hard-substrate communities at different depths and substrate orientations. Biological trends were highly correlated with sea-ice duration, and appear to be driven by opposing gradients in light and sedimentation. As sea-ice duration decreased, there was increased light and reduced sedimentation, and concurrent shifts in community structure from invertebrate to algal dominance. Trends were strongest on shallower, horizontal surfaces, which are most exposed to light and sedimentation. Depth and substrate orientation appear to mediate exposure of benthos to these factors, thereby tempering effects of sea-ice and increasing biological heterogeneity. However, while light and sedimentation both varied spatially with sea-ice, their dynamics differed temporally. Light was sensitive to the site-specific date of sea-ice breakout, whereas sedimentation fluctuated at a regional scale coincident with the summer phytoplankton bloom. Sea-ice duration is clearly the overarching force structuring these shallow Antarctic benthic communities, but direct effects are imposed via light and sedimentation, and mediated by habitat characteristics.

Data files:

Boulder_community_data.csv
- Percentage cover data for sessile organisms (invertebrates and algae) growing on boulder surfaces.
- Columns 1 to 5 are sample attributes, columns 6 to 57 are measured variables (species or bare space).

Light_budget_data.csv
- Annual light budgets at each site, recorded by light metres.
- Columns are site name and annual light budget (mol photons m-2 year-1)

Sediment_trap_data.csv
- Total sediment collected in sediment traps
- Columns are site label, position in bay, replicate, dates deployed and retrieved, and the calculated sediment flux (g m-2 d-1)

本数据集关联以下学术论文：
《海冰、光照与沉积作用对南极浅海底栖群落（benthic communities）结构的调控作用》
作者：格雷姆·F·克拉克、乔纳森·S·斯塔克、安妮·S·帕尔默、马丁·J·里德尔、艾玛·L·约翰斯顿
发表期刊：PLoS ONE

数据集包含巨砾群落（底表附着生物群，epifauna）、年度光照预算以及沉积捕集器数据，详细信息请参阅原文。

摘要
在极地海岸，季节性海冰持续时长通过改变光照、沉积作用与物理扰动等环境条件，对浅海生态系统产生强烈影响。当前，海冰动力学因气候变化发生改变，但学界对其如何影响浅海环境与底栖生物（benthos）的认知仍较为有限。本研究依托南极某海岸区域获取的独特物理与生物数据集，深入解析调控极地底栖群落结构的关键因素。研究在覆盖海冰持续时长梯度的多个样地中，测定了不同水深与基底朝向的样地内光照、沉积作用以及硬质基底群落的时空变化特征。结果显示，生物群落的变化趋势与海冰持续时长高度相关，且受光照与沉积作用的反向梯度驱动。随着海冰持续时长缩短，光照强度上升而沉积作用减弱，群落结构随之发生从无脊椎动物占优到藻类占优的转变。该趋势在较浅的水平基底表面最为显著，此类基底最易受到光照与沉积作用的影响。水深与基底朝向似乎会调节底栖生物暴露于上述环境因子的程度，进而缓和海冰的影响并提升生物群落的异质性。不过，尽管光照与沉积作用均随海冰持续时长呈现空间异质性，二者的时间动态却存在差异：光照对样地专属的海冰消退日期敏感，而沉积作用则在区域尺度上随夏季浮游植物水华发生波动。研究表明，海冰持续时长无疑是调控南极浅海底栖群落结构的核心驱动力，但其直接影响通过光照与沉积作用介导，并受生境特征的调节。

数据集文件：
1. Boulder_community_data.csv
- 记录巨砾表面固着生物（无脊椎动物与藻类）的盖度百分比数据。
- 第1至5列为样本属性字段，第6至57列为实测变量（物种或裸空间占比）。
2. Light_budget_data.csv
- 各采样点的年度光照预算数据，由光照记录仪测定。
- 字段包括样地名称与年度光照预算（单位：mol photons m⁻² year⁻¹）。
3. Sediment_trap_data.csv
- 沉积捕集器收集的总沉积物量数据。
- 字段包括样地编号、海湾内位置、重复样本编号、布设与回收日期，以及计算得到的沉积物通量（单位：g m⁻² d⁻¹）。