2016 SoE Marine Chapter - State and Trends - Algal blooms, jellyfish blooms

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 – algal blooms, jellyfish blooms". 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.

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DESCRIPTION OF ECOLOGICAL PROCESS FOR EXPERT ASSESSMENT
--Algal Blooms--
Phytoplankton produce half the oxygen we breathe and sustain our fisheries. However, some species produce toxins when they proliferate, and can discolour the water resulting in obvious blooms. These Harmful Algal Blooms (HABs) can have serious economic, health and environmental impacts. In summer 2015/2016, there was a bloom of Alexandrium tamarense along the east coast of Tasmania – the most toxic bloom in 40 years. It contaminated mussels, oysters, scallops and ultimately rock lobsters – and led to closures lasting 4 months. This followed a HAB bloom in Tasmania in 2013 that cost $23 million. Because of their impact on the environment they are the most studied of algal species that bloom, and as a result this assessment focuses on this group of algae.

There is strong scientific consensus that eutrophication is the primary factor stimulating HABs. In addition, new toxic species can be introduced through ballast water exchange and tropical species are moving poleward into new areas in Australia.

--Jellyfish Blooms--
Jellyfish are important and often conspicuous components of ecosystems. Although dense jellyfish blooms are natural in healthy systems and there is debate about whether jellyfish populations are increasing globally, persistent blooms are known to be sensitive indicators of degraded systems. Jellyfish outbreaks can cause a number of deleterious effects including losses in tourist revenue through beach closures and even death of bathers (through stings); power outages following the blockage of cooling intakes at coastal power plants; burst fishing nets and contaminated catches; killing of farmed fish; and reduction in commercial fish abundance through competition and predation.

The two primary human pressures that exacerbate jellyfish blooms are:
1. Overfishing, particularly of small pelagic species such as anchovy and sardine, which releases predation pressure on young jellyfish; and
2. Eutrophication, where increased nutrients lead to more plankton food for jellyfish.

Problematic jellyfish blooms primarily occur in bays and harbours, areas covered under the coasts chapter. This assessment will concentrate on those data available from nearshore and shelf waters for which there are currently data available.

DATA STREAM(S) USED IN EXPERT ASSESSMENT
IMOS plankton data – both from the National Reference Stations and the Australian Continuous Plankton Recorder survey.

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2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details]

• 2016 •
Assessment grade: Very good
Assessment trend: Stable
Confidence grade: Limited evidence or limited consensus
Confidence trend: Limited evidence or limited consensus
Comparability: Grade and trend somewhat comparable to the 2011 assessment
• 2011 •
Assessment grade: Very good
Assessment trend: Stable
Confidence grade: Limited evidence or limited consensus
Confidence trend: Limited evidence or limited consensus

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CHANGES SINCE 2011 SOE ASSESSMENT
Not previously assessed.

2016年《环境状况（State of the Environment, SoE）》报告海洋章节整合了多套基于海洋数据流构建的专家模板。本元数据记录对应专家评估报告《生态过程现状与趋势——藻华、水母潮》。完整的专家评估报告（含附图及附表，如已提供）已附于本记录中。若可获取，生成该专家评估所用的数据流可通过本记录的"在线资源"板块查阅。

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专家评估所用生态过程说明
--藻华--
浮游植物（Phytoplankton）贡献了人类呼吸所需的一半氧气，同时支撑着渔业发展。但部分浮游植物物种在增殖过程中会产生毒素，使水体变色并形成肉眼可见的藻华，这类有害藻华（Harmful Algal Blooms, HABs）会对经济、人类健康与生态环境造成严重负面影响。2015/2016年夏季，塔斯马尼亚东海岸爆发了链状亚历山大藻（Alexandrium tamarense）藻华——这是40年来毒性最强的一次藻华。此次藻华污染了贻贝、牡蛎、扇贝乃至岩龙虾，导致相关产业关停长达4个月。此前2013年塔斯马尼亚也曾爆发有害藻华，造成2300万澳元的经济损失。鉴于其对生态环境的显著影响，这类藻华物种是浮游植物中研究最为深入的类群，因此本评估聚焦该类藻类。

学界已形成广泛科学共识：富营养化（Eutrophication）是诱发有害藻华的核心驱动因素。此外，新型有毒藻华物种可通过船舶压载水交换传入本地海域，同时热带藻华物种正逐步向极地迁移，在澳大利亚境内开拓新的栖息区域。

--水母潮--
水母是生态系统中重要且通常较为显眼的组成部分。尽管在健康的生态系统中，高密度水母潮属于自然现象，且全球水母种群数量是否出现增长仍存在争议，但持续爆发的水母潮已被证实是生态系统退化的敏感指示物。水母大规模爆发可引发诸多负面影响：海滩关停导致旅游收入损失，甚至造成游泳者被蛰伤致死；沿海电厂冷却取水口被堵塞引发断电；渔网破损、渔获物被污染；养殖鱼类大量死亡；以及通过竞争与捕食作用降低商业鱼类种群丰度。

加剧水母潮爆发的两大主要人为压力源为：
1. 过度捕捞，尤其是鳀鱼、沙丁鱼等小型中上层鱼类的捕捞，这会降低对幼水母的捕食压力；
2. 富营养化，即营养盐输入增加为水母提供了更多浮游饵料。

具有负面影响的水母潮主要爆发于海湾与港口区域，该类区域已纳入海岸章节的评估范畴。本评估将聚焦当前可获取数据的近岸与陆架海域数据集。

专家评估所用数据流
澳大利亚海洋观测系统（Integrated Marine Observing System, IMOS）浮游生物数据，涵盖国家基准站与澳大利亚连续浮游生物记录仪（Australian Continuous Plankton Recorder）调查获取的数据集。

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2016年《环境状况》评估摘要（完整细节请参阅附件中的专家评估报告）
• 2016年 •
评估等级：优秀
评估趋势：稳定
置信等级：证据有限或共识不足
置信趋势：证据有限或共识不足
可比性：评估等级与趋势与2011年评估基本可比
• 2011年 •
评估等级：优秀
评估趋势：稳定
置信等级：证据有限或共识不足
置信趋势：证据有限或共识不足

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2011年《环境状况》评估以来的变化
本内容此前未进行过评估。