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Does turbidity induced by Carassius carassius limit phytoplankton growth? A mesocosm study

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Hu He at Chinese Academy of Sciences
Hu He
En Hu
En Hu
En Hu
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Jinlei Yu at Chinese Academy of Sciences
Jinlei Yu
Xuguang Luo
Xuguang Luo
Xuguang Luo
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Sustainable development, while simultaneously sustaining the ability of natural systems to provide ecosystem services on which the economy and society depend, is one of the most important development goals. In this review, the theories of five sustainable development pathways are presented, followed by a discussion on the influences of involuntary and voluntary practices. Specifically, this paper reviews the literature on limits to growth and on planetary boundaries, examines the critique of green growth, and outlines the debate between degrowth and a-growth. Then, the importance of economic recession as an involuntary instrument and working time reduction policies as a voluntary instrument in mitigating environmental pressure is examined. Policy implications are highlighted in the final section.
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RESEARCH ARTICLE
Does turbidity induced by Carassius carassius limit
phytoplankton growth? A mesocosm study
Hu He
1
&En Hu
1
&Jinlei Yu
1
&Xuguang Luo
2
&Kuanyi Li
1
&Erik Jeppesen
1,3,4
&
Zhengwen Liu
1,4,5
Received: 17 March 2016 /Accepted: 11 December 2016 / Published online: 20 December 2016
#Springer-Verlag Berlin Heidelberg 2016
Abstract It is well established that benthivorous fish in shal-
low lakes can create turbid conditions that influence phyto-
plankton growth both positively, as a result of elevated nutri-
ent concentration in the water column, and negatively, due to
increased attenuation of light. The net effect depends upon the
degree of turbidity induced by the benthivores. Stocked
Carassius carassius dominate the benthivorous fish fauna in
many nutrient-rich Chinese subtropical and tropical shallow
lakes, but the role of the species as a potential limiting factor in
phytoplankton growth is ambiguous. Clarification of this re-
lationship will help determine the management strategy and
cost of restoring eutrophic lakes in China and elsewhere. Our
outdoor mesocosm experiment simulating the effect of high
density of crucian carp on phytoplankton growth and commu-
nity structure in eutrophic shallow lakes suggests that stocking
with this species causes resuspension of sediment, thereby
increasing light attenuation and elevating nutrient concentra-
tions. However, the effect of light attenuation was insufficient
to offset the impact of nutrient enhancement on phytoplankton
growth, and significant increases in both phytoplankton bio-
mass and chlorophyll aconcentrations were recorded. Crucian
carp stocking favored the dominance of diatoms and led to
lower percentages (but not biomass) of buoyant
cyanobacteria. The dominance of diatoms may be attributed
to a competitive advantage of algal cells with high sedimen-
tation velocity in an environment subjected to frequent crucian
carp-induced resuspension and entrainment of benthic algae
caused by the fish foraging activities. Our study demonstrates
that turbidity induced by stocked crucian carp does not limit
phytoplankton growth in eutrophic waters. Thus, removal of
this species (and presumably other similar taxa) from subtrop-
ical or tropical shallow lakes, or suspension of aquaculture, is
unlikely to boost phytoplankton growth, despite the resulting
improvements in light availability.
Keywords Crucian carp .Nutrients .Resuspension .
Suspended solids .Phytoplankton community .Shallow
lakes .China
Introduction
In most shallow lakes, benthivorous fish such as common carp
(Cyprinus carpio) are important factors determining water
clarity (Weber and Brown 2009;Bernesetal.2013; Villizzi
et al. 2015). Benthivorous fish select food by sucking in sed-
iment and ejecting all but the retained food particles back into
the water column. The process often causes sediment resus-
pension, resulting in non-algal turbidity (hereafter referred to
as Bturbidity^) in the water column (Richardson et al. 1995).
Communicated by: Thomas Hein
Electronic supplementary material The online version of this article
(doi:10.1007/s11356-016-8247-z) contains supplementary material,
which is available to authorized users.
*Hu He
hehu@niglas.ac.cn
1
State Key Laboratory of Lake Science and Environment, Nanjing
Institute of Geography and Limnology, Chinese Academy of
Sciences, 73 East Beijing Road, Nanjing 210008, China
2
College of Animal Science, Inner Mongolia Agricultural University,
Hohhot 010018, China
3
Department of Bioscience, Aarhus University, Aarhus, Denmark
4
Sino-Danish Centre for Education and Research, Beijing 100049,
China
5
Department of Ecology and Institute of Hydrobiology, Jinan
University, Guangzhou 510632, China
Environ Sci Pollut Res (2017) 24:5012–5018
DOI 10.1007/s11356-016-8247-z
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
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Article
  • Jan 2007
通过食物组成分析和渔获物组成调查, 并结合历年渔获量统计和环境监测资料, 研究了太湖鲫鱼数量变化的规律、机制及与环境间的相互关系。渔获物调查和渔获量统计资料均表明:近年鲫鱼数量不断增加, 已成为太湖仅次于鲚鱼的重要鱼类。2004年渔获物调查中, 鲫鱼占鱼类总重量的8.40％±2.69％, 占鲤、鲫鱼渔获量的65.08％±15.47％;历年渔获量统计显示, 1952-1998年鲤、鲫鱼渔获量相对稳定在1010.1±367.2t、占鱼类总量8.89％±5.33％, 1999年上升达到2547.4t、占9.45％, 2000年达到3708.7t, 占12.18％;年龄组成分析表明, 鲫鱼低龄化趋势在加剧。食性分析表明:在7-12月, 微囊藻占鲫鱼食物体积的83.65％-93.99％。分析认为:太湖鲫鱼以微囊藻为主要食物;富营养化加重为其提供了充足饵料, 实施禁渔期、禁渔区等措施使其繁殖得到保障, 捕捞强度过高导致其年龄组成低龄化、个体小型化。而太湖鲫鱼以蓝藻为主要食物, 可能对蓝藻有抑制作用。Based on the analysis of food content and the survey of the composition in fish catches and the data of fish catches in Lake Taihu, the amount changes of catches of Carassius auratus Linnaeus and Their Mutual Relationship with Environment were studied.The results of the survey of fish composition in 2004 and the statistics data of fish catches from 1952 to 2004 showed that:Within recent years, the catches of Carassius auratus Linnaeus had been increasing and had become the second dominant fishes following Coilia ectenes taihuensis Yen et Lin.The a-nalysis of age structure showed that the percentage of 0⁺ fishes increased and the average fish body size decreased.For example, the percentage of 0⁺Carassius auratus Linnaeus had been increasing according to the trend of y=19.154e0.0566x(y means the percentage of 0⁺fishes %, x means time a).And the average body length had been decreasing according to the trend of y=115.45e-0.0312x(y means body size cm, x means time a).The results of food content analysis showed that:the percentage of blue-algae accounted for about 83.65%-93.99% of food volume of Carassius auratus Linnaeus.Under the conditions of eutrophication in Lake Taihu, Carassius auratus Linnaeus mainly fed on blue-algae;eutrophication resulted in the increasing of blue-algae which could be eaten by the fish.The measures of protecting fishes were carried out to ensure the fish propagating.In addition, the trend of percentage of low age fishes increasing and the trend of body size of the fishes decreasing were caused by over-fishing.Carassius auratus Linnaeus might restrain blue-algae increasing because it mainly fed on blue-algae.
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Successful restoration of a tropical shallow eutrophic lake: strong bottom-up but weak top-down effects recorded
Conference Paper
  • Oct 2014
Fish manipulation has been used to restore lakes in the temperate zone. Often strong shortterm cascading effects have been obtained, but the long term-perspectives are less clear. Fish manipulation methods are far less advanced for warm lakes, and it is debatable whether it is, in fact, possible to create a trophic cascade in warm lakes due to the dominance and high densities of fast-reproducing omnivorous fish. However, other important aims of fish manipulation, for instance, the removal of benthic feeding fish, are to reduce disturbance of the sediment, which not only affects the nutrient level but also the concentration of suspended organic and inorganic matter with reduced clarity as a result, and hampers growth of submerged macrophytes. We conducted a biomanipulation experiment in two basins of Chinese Huizhou West Lake that has remained highly turbid after extensive nutrient loading reduction. A third basin was used as control (controltreatment pairing design). Removal of a substantial amount of plankti-benthivorous fish was followed by planting of submerged macrophytes and stocking of piscivorous fish. We found strong and relatively long-lasting effects of the restoration initiative in the form of substantial improvements in water clarity and major reductions in nutrient concentrations, particularly total phosphorus, phytoplankton and turbidity, while only minor effects were detected for crustacean zooplankton grazers occurring in low densities before, as well as after the restoration. Our results add importantly to the existing knowledge of restoration of warm lakes and are strongly relevant, not least in Asia where natural lakes frequently are used extensively for fish production, often involving massive stocking of benthivorous fish. With a growing economy and development of more efficient fish production systems, the interest in restoring lakes is increasing world-wide. We found convincing evidence that fish removal and piscivores stocking combined with transplantation of submerged macrophytes may have a substantial role in conservation and management of warm water lakes.
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