Muawanah. 2012. Pasang Merah Muncul di Teluk Lampung. Koran Lampung Post. 25

Oktober 2012

Risuana, IGS., IG Hendrawan, dan Y Suteja. 2017. Distribusi Spasial Total Padatan

Tersuspensi Puncak Musim Hujan Di Permukaan Perairan Teluk Benoa, Bali. Journal of

Marine and Aquatic Sciences 3(2), 223-232.

Suteja, Y.., AIS Purwiyanto. 2018. Nitrate and phosphate from rivers as mitigation of

eutrophication in Benoa bay, Bali-Indonesia. IOP Conf. Series: Earth and Environmental

Science 162 , 012021

Suteja, Y., IGNP Dirgayusa. 2017. Deteksi Awal Eutrofikasi Teluk Benoa Sebagai Upaya

Mitigasi Harmful Alga Blooms (HABs). Laporan Akhir HUPS.

Wardiatno Y., A. Damar dan B. Sumartono. 2004. A Short Review on the Recent Problem

of Red Tide in Jakarta Bay: Effect of Red Tide on Fish and Human. Jurnal Ilmu-Ilmu

Perairan dan Perikanan Indonesia. Vol 11(1):67-71

Introduction Eutrophication defined as an increase the amount of organic material (especially plankton and or

chlorophyll) in an aquatic ecosystem caused by the increasing of nutrients by human activities.

The most dangerous eutrophication effect is Harmful Alga Blooms (HABs). HABs are an increase

in the abundance of individual plankton in aquatic ecosystems which can cause anoxia or

hypoxia or the production of poisons that can cause the death for organisms . HABs started by

eutrophic condition have occurred in Lampung and Jakarta Bay (Wardianto et al., 2004

Muawanah, 2012). Previous research showed that Benoa Bay in hypereutrophic base on

nutrient. This can initiate the growth of chlorophyll and phytoplankton for HABs. This study aims

to identify the types and abundance of potentially HABs phytoplankton, and determine the trophic

level based on chlorophyll and phytoplankton in Benoa Bay

CHLOROPHYLL AND PHYTOPLANKTON ANALYSIS FOR INITIAL DETECTION

OF EUTROFICATION AND HARMFUL ALGA BLOOMS (HABs) IN BENOA BAY Y. Suteja1*, I G. N. P. Dirgayusa1

1Marine Science Department, Faculty of Marine and Fisheries, Udayana University. Jalan Raya Kampus Kampus Bukit Jimbaran, Universitas Udayana

*Corresponding author: yuliantosuteja@unud.ac.id

Research Methods

Results and Discussion Conclusion This study found that there were 6 genera that had the potential of HABs. The

abundance of phytoplankton and chlorophyll shows an increase concentration near the

land and river estuary. The Coscinodiscus is a genus with the highest abundance.

Trophic level in Benoa Bay based on phytoplankton abundance and chlorophyll

concentration are oligotrophic. Even though Benoa Bay dominated in oligotrophic

category, the alertness of HABs must be considered because there is 1 genus that has

the potential to produce toxins and 5 genuses that can cause damage if algae blooms

occur.

Thank You Note The author give thanks to Udayana University for fully supporting this research through

Hibah Unggulan Program Studi. We also thanks to Anna Ida for her friendly constructive

suggestion and discussion.

Bibliography

Data Collection

INSITU (pH, Temperature, Salinity, DO, Turbidity)

EXSITU (Chlorophyll and phytoplankton abundance)

Spatial Mapping

Trophic Level

Figure 2. Abundance of HABs (red) and non-HABs (Green) plankton in Benoa Bay

Figure 1. research methods

Figure 3. Percentage of HABs (red) and

non-HABs (Green) plankton abundance in

Benoa Bay

From the identified phytoplankton, there were 6

genera that were potentially HABs. From the 6

genera, only one genera can be found which

can produce toxins (Nitzicia), while the other

genera (Coscinodiscus, Skeletonema,

Chaetoceros, Odontella, and Rhizosolenia) are

genera that cannot produce toxins but can

cause damaging effects if the population

blooming.

This study also show that the Benoa Bay was

dominated (75%) by plankton that have

potential of HABs (Figure 3).

Figure 4. Spatial distribution of plankton (left) and chlorophyll (right) in Benoa Bay

Figure 5. Trophic Level of plankton (left) and chlorophyll (right) in Benoa Bay

This study show that the plankton abundance and chlorophyll concentration increase

near the land and estuary (Figure 4). This is allegedly caused by an increase in nutrients.

Previous research by Suteja and Dirgayusa (2017) and Rahayu et al. (2018) shows an

increase of nutrient concentrations near land and estuary. Suteja and Purwiyanto (2018)

also explained that the nutrient load from the river to the Benoa Bay was very large.

Based on plankton abundance and chlorophyll concentration, Benoa Bay is in

oligotrophic condition (Figure 5). This is presumably due to the high turbidity and Total

Suspended Solid (TSS) which reducing the sunlight penetration. Risuana et al (2017)

explained that TSS concentrations in Benoa Bay had exceeded the quality standards set

by the government.