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.----------------------------------------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 ASSESSMENTIMOS plankton data – both from the National Reference Stations and the Australian Continuous Plankton Recorder survey.----------------------------------------2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details]• 2016 •Assessment grade: Very goodAssessment trend: StableConfidence grade: Limited evidence or limited consensusConfidence trend: Limited evidence or limited consensusComparability: Grade and trend somewhat comparable to the 2011 assessment• 2011 •Assessment grade: Very goodAssessment trend: StableConfidence grade: Limited evidence or limited consensusConfidence trend: Limited evidence or limited consensus----------------------------------------CHANGES SINCE 2011 SOE ASSESSMENTNot 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开发的专家模板。本元数据记录所描述的专家评估主题为《生态过程的现状与趋势——藻华、水母潮》。本记录已附带完整的专家评估文件（含所提供的图表与表格）。若有可用数据，用于生成本次专家评估的数据流可通过本记录的“在线资源”板块获取。

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专家评估生态过程说明——藻华——
浮游植物（Phytoplankton）贡献了人类呼吸所需的半数氧气，并支撑了全球渔业发展。然而部分浮游植物物种在增殖过程中会产生毒素，同时导致水体变色，形成肉眼可见的藻华。此类有害藻华（Harmful Algal Blooms, HABs）会造成严重的经济、健康与环境损害。2015/2016年夏季，塔斯马尼亚东海岸暴发了塔玛亚历山大藻（Alexandrium tamarense）藻华——这是40年来毒性最强的一次藻华事件。该藻华污染了贻贝、牡蛎、扇贝，最终波及岩龙虾产业，导致相关捕捞与养殖活动关停长达4个月。此前2013年塔斯马尼亚发生的有害藻华事件已造成2300万澳元的经济损失。由于该类藻华物种对环境影响显著，它们是所有藻华类物种中研究最为深入的类群，因此本次评估将聚焦于此类藻类。

科学界已形成广泛共识，富营养化是驱动有害藻华暴发的首要因素。此外，新型有毒藻类可通过压舱水交换引入新海域，同时澳大利亚的热带藻类物种正逐步向高纬度海域扩散。

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。尽管密集的水母潮在健康的生态系统中属于自然现象，且全球水母种群数量是否上升仍存在学术争议，但持续暴发的水母潮已被证实是生态系统退化的敏感指示因子。水母暴发会引发诸多负面影响：包括因海滩关停导致的旅游收入损失、游泳者蛰伤致死；沿海发电厂冷却取水口被堵塞引发的停电事故；渔网破损、渔获物被污染；养殖鱼类大规模死亡；以及通过捕食与资源竞争导致商业鱼类种群数量下降。

加剧水母潮暴发的两大核心人为压力为：1. 过度捕捞，尤其是鳀鱼、沙丁鱼等小型中上层鱼类的捕捞，此举会降低对幼水母的捕食压力；2. 富营养化，营养盐输入增加会为水母提供更充足的浮游生物食物来源。

问题性水母潮主要发生在海湾与港口区域，此类海域属于海岸章节的覆盖范畴。本次评估将聚焦于当前可获取的近岸与陆架海域相关数据。

本次专家评估使用的数据流
澳大利亚海洋科学研究所（IMOS）浮游生物数据——涵盖国家基准站监测数据与澳大利亚连续浮游生物记录仪调查数据。

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2016年环境状况报告评估摘要（完整细节见附件专家评估文件）
• 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年评估大致可比
• 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年环境状况报告以来的评估变更
此前未针对该主题开展过评估。